ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Nitrogen fixation
  • Springer  (315)
  • National Academy of Sciences
  • Periodicals Archive Online (PAO)
  • 1995-1999  (57)
  • 1985-1989  (142)
  • 1980-1984  (116)
  • 1955-1959
Collection
Keywords
Publisher
  • Springer  (315)
  • National Academy of Sciences
  • Periodicals Archive Online (PAO)
  • Wiley-Blackwell  (1)
Years
Year
  • 1
    Electronic Resource
    Electronic Resource
    Effect of soil treatment with cereal straw and method of crop establishment on field pea (Pisum sativum L.) N2 fixation (1997)
    Springer
    Biology and fertility of soils 24 (1997), S. 87-95 
    Details
    ISSN: 1432-0789
    Keywords: Crop rotation ; Field pea ; Mineral N ; Nitrogen fixation ; immobilisation ; Pisum sativum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effects of soil incorporation with cereal straw (nil, 2.5, 5 and 10 t straw ha−1) and direct drilling on the proportion and amount of pea N derived from biological N fixation were investigated in three field experiments. Fixed N was determined by15N dilution using barley as a reference plant. The three sites were on acidic, red clay-loams in the cropping zone of southeastern Australia. Seasonal plant available soil N, as determined by the N accumulated in barley, was 31, 56 and 158 kg N ha−1, for the three sites. Incorporated straw reduced soil nitrate at sowing by 10–50 kg N ha−1 (0–30 cm), and 5 or 10 t straw ha−1 reduced barley uptake of N by 10–38 kg N ha−1. However, reducing plant available soil N was generally ineffective for increasing the N fixed by pea. Fixed N increased only at the site with the least plant-available N, and only one-third of the increase could be attributed to lower soil N uptake by pea. There was no evidence that direct drilling pea increased fixed N by decreasing crop uptake of soil N. It is proposed that a lower requirement for soil N by pea as compared to barley, and availability of mineral N beneath the soil layer treated with straw, minimise the effectiveness of straw incorporation for increasing the N fixed by pea.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01420226
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Effect of soil treatment with cereal straw and method of crop establishment on field pea (Pisum sativum L.) N2 fixation (1996)
    Springer
    Biology and fertility of soils 24 (1996), S. 87-95 
    Details
    ISSN: 1432-0789
    Keywords: Key words Crop rotation ; Field pea ; Mineral N ; Nitrogen fixation ; immobilisation ; Pisum sativum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effects of soil incorporation with cereal straw (nil, 2.5, 5 and 10 t straw ha–1) and direct drilling on the proportion and amount of pea N derived from biological N fixation were investigated in three field experiments. Fixed N was determined by 15N dilution using barley as a reference plant. The three sites were on acidic, red clay-loams in the cropping zone of southeastern Australia. Seasonal plant available soil N, as determined by the N accumulated in barley, was 31, 56 and 158 kg N ha–1, for the three sites. Incorporated straw reduced soil nitrate at sowing by 10–50 kg N ha–1 (0–30 cm), and 5 or 10 t straw ha–1 reduced barley uptake of N by 10–38 kg N ha–1. However, reducing plant available soil N was generally ineffective for increasing the N fixed by pea. Fixed N increased only at the site with the least plant-available N, and only one-third of the increase could be attributed to lower soil N uptake by pea. There was no evidence that direct drilling pea increased fixed N by decreasing crop uptake of soil N. It is proposed that a lower requirement for soil N by pea as compared to barley, and availability of mineral N beneath the soil layer treated with straw, minimise the effectiveness of straw incorporation for increasing the N fixed by pea.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01420226
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Nitrogen-fixing stem nodules on Aeschynomene afraspera (1987)
    Springer
    Biology and fertility of soils 4 (1987), S. 61-66 
    Details
    ISSN: 1432-0789
    Keywords: Stem nodulation ; Aeschynomene afraspera ; Legume ; Nitrogen fixation ; Acetylene reduction assay (ARA)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Aeschynomene afraspera is a wild annual legume growing in periodically waterlogged soils in western Africa. This legume is characterized by a profuse stem nodulation. Nodules are formed on the stem at the emergence of lateral root primordia, called nodulation sites. These sites are irregularly distributed on vertical rows all along the stem and branches. Stem nodules are hemispherically shaped. Their outside is dark green and they contain a red-pigmented central zone. Stem nodules exhibit a high nitrogen-fixing potential. Acetylene reduction assays result in stem nodule activity of 309 μmol C2H4 g−1 dry nodule h−1. Field-grown stem nodulated Aeschynomene accumulated more N (51 g N m−2 in 10 weeks) than the root nodulated one. Because of this nitrogenfixing potential and its ability to grow in waterlogged conditions, A. afraspera could probably be introduced into tropical rice cropping systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00280352
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Azospirillum — plant root associations: A review (1989)
    Springer
    Biology and fertility of soils 8 (1989), S. 356-368 
    Details
    ISSN: 1432-0789
    Keywords: Plant-root associations ; Azospirillum spp ; Rhizosphere ; Nitrogen fixation ; Acetylene reduction assay (ARA) ; Phytohormones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Bacteria of the genus Azospirillum are extensively studied for their plant-growth promoting effect following inoculation. Physiological and biochemical studies of these diazotrophic bacteria are now benefiting from recent breakthroughs in the development of genetic tools for Azospirilum. Moreover, the identification and cloning of Azospirillum genes involved in N2 fixation, plant interaction, and phytohormone production have given new life to many research projects on Azospirillum. The finding that Azospirillum genes can complement specific mutations in other intensively studied rhizosphere bacteria like Rhizobia will certainly trigger the exploration of new areas in rhizosphere biology. Therefore a review of the Azospirillum-plant interactions is particularly timely.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00263169
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Influence of phosphorus or phosphorus-potassium fertilization on biomass and dinitrogen fixation of the stem-nodulating green-manure legume Sesbania rostrata in different marginally productive wetland rice soils (1995)
    Springer
    Biology and fertility of soils 20 (1995), S. 107-112 
    Details
    ISSN: 1432-0789
    Keywords: Wetland rice soils ; Nitrogen fixation ; Sesbania rostrata ; PK fertilization ; Soil Mn ; Acetylene reduction assay ; ARA ; Green manure ; N dilution method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The performance of Sesbania rostrata varies widely from site to site. This makes it difficult to predict the N yield and biomass of this plant in marginally productive soils, and to arouse the interest of farmers in green manure technology. Three consecutive pot experiments were conducted in a greenhouse at the International Rice Research Institute (IRRI) to evaluate growth, nodulation, N2 fixation (C2H2 reduction assay and 15N dilution method), and N yield of 6-week-old S. rostrata on 13 physicochemically different wetland rice soils of the Philippines and on three artificial substrates. The performance of S. rostrata on the unfertilized controls was compared with two fertilizer treatments containing either P (100 mg P kg-1 dry soil) or P+K (100 mg P kg-1 and 200 mg K kg-1 dry soil). In the control soils and substrates, the N yield of S. rostrata varied between 20 and 470 mg N per pot, with the N rate from N2 fixation ranging between 0 and 95%. In three of the nutritionally poor soils even Mn toxicity symptoms apparently occurred with S. rostrata. P application alleviated these symptoms and increased the overall N yield considerably, mainly through increased biological N2 fixation. An additional increase in N yield was obtained by the PK treatment. Multiple regression analysis between soil characteristics and the N yield of S. rostrata showed that the original level of P (Olsen-extracted) and Mn in the soil accounted for 73% of the variance in biomass production by S. rostrata among the unfertilized soils and substrates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00336588
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    The role of potassium fertilizer in nodulation and nitrogen fixation of faba bean (Vicia faba L.) plants under drought stress (1995)
    Springer
    Biology and fertility of soils 20 (1995), S. 147-150 
    Details
    ISSN: 1432-0789
    Keywords: Faba bean ; Water stress ; Nodulation ; Nitrogen fixation ; Leghaemoglobin ; Invertase ; Protease ; K fertilizer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Three-week-old nodulated faba bean plants were subjected to different levels of drought stress (onehalf, one-quarter, or one-eighth field capacity) for 5 weeks. Half the stressed plants were treated with KCl at 10 mg kg-1 soil or 150 mg kg-1 soil at the beginning of the drought stress. Nodulation and nitrogenase activity were significantly decreased by increasing drought stress. Leghaemoglobin and protein contents of nodule cytosol were also severely inhibited by drought sttess. This decline was attributed to the induction of protease activity. However, carbohydrate contents of the nodule cytosol increased significantly. This accumulation was attributed to a sharp decline in invertase activity and low use of sugar by the bacteroids We conclude that harmful effects of water deficits can be alleviated by increasing K+ supplementation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00336594
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Dynamics of nodulation, nitrogen fixation, nitrogen use and biomass yield over time in pot-grown Leucaena leucocephala (Lam.) de Wit (1995)
    Springer
    Biology and fertility of soils 20 (1995), S. 163-168 
    Details
    ISSN: 1432-0789
    Keywords: Leucaena ; Nodulation ; Nitrogen fixation ; Nitrogen use ; 15N ; Time course
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The dynamics of nodulation, N2-fixation and N use in Leucaena leucocephala cv. K28 over time was investigated in a screenhouse at 4, 8, 12 and 16 months after planting (MAP) using the 15N-labelling method. Leucaena had a consistently increasing pattern of nodulation, dry biomass and nitrogen yield. A sharp rise in nodulation was observed between 12 and 16 MAP, whereas for biomass, N accumulation and N2-fixation, and N2-fixation, an upward surge occurred between 4 and 12 months. Nodulation, N accumulation, N2-fixation and biomass yield all peaked at 16 MAP. Along with the steady increase in N2-fixation throughout the 16-month growth period, the % N derived from the atmosphere rose from 17.9% to 61.5%, 70.1% and 74%, equivalent to 191, 1623, 2395 and 3385 mg N2 fixed plant-1 at 4, 8, 12 and 16 MAP, respectively. Nitrogen assimilation from soil and fertilizer decreased inversely to the increase in symbiotic nitrogen fixation with time.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00336553
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Comparison of symbiotic effectiveness of Rhizobium sp. with positive hydrogen-uptake activity compared with negative mutants in relation to nitrogen fixation in mungbean (Vigna radiata L.) (1995)
    Springer
    Biology and fertility of soils 20 (1995), S. 270-274 
    Details
    ISSN: 1432-0789
    Keywords: Mungbean ; Vigna radiata ; Nitrogen fixation ; Hydrogen uptake ; Mutation ; Nitrosoguanidine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract H2 uptake activity was well distributed in Rhizobium sp. strains isolated from nodules of mung-bean (Vigna radiata L.). Two effective strains, RMP1 und RMP2, exhibiting significantly higher H2 uptake activity were subjected to mutagenesis with nitrosoguanidine. The respective mutation frequencies were 0.18 and 0.19%. Three Hup- mutants each of RMP1 und RMP2 were compared with the wild-type parent strains under pot culture experiments to evaluate the significance of the H2 uptake system in biological N2 fixation. Nodulation capabilities, plant growth characteristics, and the chlorophyll content of the leaves were significantly reduced in the plants treated with Hup- mutants. Nitrogenase activity in Hup- nodules was reduced by 8–41%. Similarly, N accumulation was also reduced singificantly.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00336089
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Occurrence of the endophytic diazotrophs Herbaspirillum spp. in roots, stems, and leaves, predominantly of Gramineae (1996)
    Springer
    Biology and fertility of soils 21 (1996), S. 197-200 
    Details
    ISSN: 1432-0789
    Keywords: Herbaspirillum ; Endophytes of Gramineae ; Diazotrophs ; Survival in soil ; Nitrogen fixation ; sugarcane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Since the first description of Herbaspirillum seropedicae in 1986, few data have been published on this diazotroph, possibly due to difficulties in isolating it from soil. In the present study we found that this bacterium seems to be an obligate endophyte which has been isolated from roots, stems, and leaves of a large number of samples of more than 10 different species of the Gramineae family, but only exceptionally from other plants. H. rubrisubalbicans, previously misnamed as “Pseudomonas” rubrisubalbicans, and known as a mild pathogen of sugarcane causing mottled stripe disease, confirms the endophytie habitat of this genus. This species occurs in roots, stems, and leaves of sugarcane and seems to be restricted to this crop. Inoculation of strains from both species into soil in high numbers resulted in a rapid decline in their numbers. In only 30 days the population of Herbaspirillum spp. in soil decreased below detection limits (〈100 cells g-1). When sorghum was planted in this soil, the bacteria reappeared and multiplied within the plant tissues.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00335935
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Short- and long-term effects of ammonium on photodependent nitrogen fixation in wetland rice fields of Spain (1997)
    Springer
    Biology and fertility of soils 24 (1997), S. 353-357 
    Details
    ISSN: 1432-0789
    Keywords: Key words Acetylene reduction assay ; Anabaena sp. ; Ammonium ; Cyanobacteria ; Nitrogen fixation ; Wetland rice fields ; Nitrogenase activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Short- and long-term experiments were conducted in the rice fields of Valencia, Spain, to determine the ecological significance of ammonium on nitrogen fixation. A significant inhibition of nitrogenase activity by ammonium, at concentrations higher than 0.5mM, was observed after 8h of incubation in short-term experiments done with a bloom of the N2-fixing cyanobacterium Anabaena sp. In a second set of short-term experiments for in situ assays of nitrogenase activity in the field, a significant correlation between nitrogenase activity and the number of N2-fixing cyanobacteria in soil was found. No significant inhibition of nitrogenase activity by ammonium at concentrations up to 2mM was observed in these assays after 24h of incubation. This lack of inhibition was probably due to the rapid decrease in ammonium content in the flood water. Only 5% of the ammonium initially added remained in the water 24h later. In the long-term experiments, nitrogenase activity was assayed in plots fertilized with 0, 70 and 140kgNha–1, over the cultivation cycle, for 5 years. A partial inhibition of nitrogenase activity by deep-placed N fertilizers was observed. Differences were only significant in 2 years. Mean results from 5 years only showed significant differences between plots fertilized with 0 and 140kgNha–1. The partial inhibition of nitrogenase activity by ammonium increased over the cultivation cycle. Inhibition was only significant in September, at the end of the cultivation cycle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003740050257
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 11
    Electronic Resource
    Electronic Resource
    Phenotypic grouping of Brazilian Bradyrhizobium strains which nodulate soybean (1997)
    Springer
    Biology and fertility of soils 25 (1997), S. 407-415 
    Details
    ISSN: 1432-0789
    Keywords: Key wordsBradyrhizobium japonicum ; Bradyrhizobium elkanii ; Genetic variability ; Glycine max ; Nitrogen fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Several years of research have shown that there is a high genetic and physiological variability among Bradyrhizobium japonicum strains, culminating in a subdivision into two bacterial genotypes, and the description of the new species B. elkanii. In Brazil, large-scale soybean inoculation started in 1960 and today 15 million doses of inoculants are sold per year for an estimated area of 12 million ha. Efforts have been made to find strains able to fix high amounts of N2 under Brazilian soil conditions, but few laboratories cover basic studies on N2 fixation, such as strain classification into the two Bradyrhizobium species. In this study several characteristics of 40 soybean Bradyrhizobium strains, including 4 reference strains of B. japonicum (genotype I) species, 3 of B. elkanii (genotype II) and 1 of a mixed genotype were evaluated. The parameters analysed in vitro were: colony morphology, serological grouping, intrinsic resistance to antibiotics, synthesis of indole acetic acid, expression of hydrogenase activity and growth in a medium enriched with asparagine. In vivo, analyses performed included the nodulation of Rj 4 soybean cultivar Hill and the detection of symptoms caused by rhizobitoxine. These evaluations allowed a phenotypic grouping which positioned most of the strains utilized in Brazilian inoculants and studies, as well as some new strains isolated from the Cerrado region, within the species B. elkanii. However, environmental stresses and adaptation of Bradyrhizobium strains to the soil caused a large physiological and genetic variability in some isolates from the Cerrado soils in relation to the putative parental strain introduced 15 years ago, placing these isolates in an intermediate position between the two Bradyrhizobium species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003740050333
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    Nodulation pattern and acetylene reduction (nitrogen fixation) activity of some highland and lowland Acacia species of Ethiopia (1998)
    Springer
    Biology and fertility of soils 27 (1998), S. 60-64 
    Details
    ISSN: 1432-0789
    Keywords: Key words Acacia spp. ; Bradyrhizobium ; Rhizobium ; Nitrogen fixation ; Nitrogen accumulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  Endosymbionts from the Ethiopian highland acacia species Acacia abyssinica, A. negrii and A. etbaica, and the lowland species A. nilotica, A. prasinata, A.senegal, A. seyal, A. tortilis and Faidherbia (Acacia) albida were isolated and characterized. Seven tree species were found to be nodulated by species of both Rhizobium and Bradyrhizobium. F. (Acacia) albida and A. senegal were nodulated by only Bradyrhizobium or Rhizobium, respectively. In A. abyssinica, both genera were isolated from the same nodule, whereas in A. nilotica and A. tortilis, both strains were isolated from different nodules of the same plant. The nitrogen fixation (acetylene reduction) activities varied considerably and showed no correlation with the nitrogen content of the plant. Highland species were as effective as lowland plants, thus demonstrating good potential for soil reclamation. The endosymbionts isolated proved rather promiscuous, efficiently nodulating other Acacia spp. and some tropical grain legumes, but did not nodulate temperate legumes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003740050400
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    Nitrogen fixation capacity and nodule occupancy by Bradyrhizobium japonicum and B. elkanii strains (1998)
    Springer
    Biology and fertility of soils 27 (1998), S. 393-399 
    Details
    ISSN: 1432-0789
    Keywords: Key words Bradyrhizobium japonicum ; Bradyrhizobium elkanii ; Competitiveness ; Nitrogen fixation ; Soybean
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  In a previous study soybean Bradyrhizobium strains, used in Brazilian studies and inoculants over the last 30 years, and strains adapted to the Brazilian Cerrados, a region frequently submitted to environmental and nutritional stresses, were analyzed for 32 morphological and physiological parameters in vivo and in vitro. A cluster analysis allowed the subdivision of these strains into species Bradyrhizobium japonicum, Bradyrhizobium elkanii and a mixed genotype. In this study, the bacteria were analyzed for nodulation, N2 fixation capacity, nodule occupancy and the ability to increase yield. The goal was to find a relationship between the strain groups and the symbiotic performance. Two strains of Brazilian B. japonicum showed higher rates of N2 fixation and nodule efficiency (mg of N mg–1 of nodules) under axenic conditions. These strains also showed greater yield increases in field experiments when compared to B. elkanii strains. However, no differences were detected between B. japonicum and B. elkanii strains when comparing nodule occupancy capacity. The adapted strains belonging to the serogroup B. elkanii SEMIA 566, most clustered in a mixed genotype, were more competitive than the parental strain, and some showed a higher capacity of N2 fixation. Some of the adapted strains, such as S-370 and S-372, have shown similar N2 fixation rates and nodulation competitiveness to two Brazilian strains of B. japonicum. This similarity demonstrates the possibility of enhancing N2 fixing ability, after local adaptation, even within B. elkanii species. Differences in the DNA profiles were also detected between the parental SEMIA 566 and the adapted strains by analyses with the ERIC and REP-PCR techniques. Consequently, genetic, morphological and physiological changes can be a result of adaptation of rhizobia to the soil. This variability can be used to select strains capable of increasing the contribution of N2 fixation to soybean nutrition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003740050449
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    Effect of inoculum rate on the performance of chickpea (Cicer arietinum L.) Rhizobium strains in the field (1987)
    Springer
    Biology and fertility of soils 5 (1987), S. 83-87 
    Details
    ISSN: 1432-0789
    Keywords: Inoculation ; Inoculum dose ; Nitrogen fixation ; Chickpea ; Rhizobium spp. ; Cicer arietinum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The influence of three inoculum rates on the performance of three chickpea (Cicer arietinum L.) Rhizobium strains was examined in the field on a Mollisol soil. Increasing amounts of inoculum improved the performance of the strains. A normal dose (104 cells per seed) applied at different intervals gave non-significant increases in nodulation, nitrogenase activity (acetylene reduction assay), nitrogen uptake and grain yield. A ten-fold increase in inoculum increased nodule number, shoot dry weight, nitrogenase activity (ARA) and grain yield, but increases over the control were significant only for nodule dry weight and nitrogen uptake by shoot and grain. The highest level of inoculum (100 × normal) significantly increased nodule dry weight, grain yield, total nitrogenase activity (ARA) and nitrogen uptake by shoot and grain. Strain TAL 620 was more effective than the other two. Combined nitrogen (60 kg N ha−1) suppressed nodulation and nitrogenase activity (ARA).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00264351
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 15
    Electronic Resource
    Electronic Resource
    Presence and dispersal of infective Frankia in peat and meadow soils in Sweden (1988)
    Springer
    Biology and fertility of soils 6 (1988), S. 39-44 
    Details
    ISSN: 1432-0789
    Keywords: Alnus ; Energy forestry ; Frankia ; Meadow soil ; Nitrogen fixation ; Nodulation ; Peat soil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Use of the N2-fixing grey alder, Alnus incana (L.) Moench, as a short-rotation crop for energy production is currently being explored. To evaluate the need for inoculation of alders, the distribution of infective propagules of Frankia in the soil at potential sites for alder plantations was examined. Uninoculated grey alder seedlings were grown in three types of soil. Frequent nodulation was found in a meadow soil which had been free from actinorhizal plants for nearly 60 years, but the alder seedlings failed to nodulate in peat soil from two different bog sites. One of these bogs had been exploited for peat and the surface layer of the peat had been removed, so that the soil samples were taken from deep layers of the peat. At the other site, an area of cultivated peat, there were no infective propagules of Frankia in plots without alders; the infective Frankia was present in plots only where it had been introduced by inoculated alders. There was no detectable air-borne dispersal of Frankia. Instead, water movement might account for the dispersal of Frankia in peat. Although the apparent absence of Frankia in these peat soils necessitates inoculation of alder seedlings before planting out, this makes it possible to introduce and maintain Frankia strains with selected beneficial characteristics, since there is no competition from an indigenous Frankia flora.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00257918
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 16
    Electronic Resource
    Electronic Resource
    Renodulation and characterization of Rhizobium isolates from cicer milkvetch (Astragalus cicer L.) (1997)
    Springer
    Biology and fertility of soils 25 (1997), S. 169-174 
    Details
    ISSN: 1432-0789
    Keywords: Key wordsAstragalus cicer ; Nodulation ; DNA ; Milkvetch ; Nitrogen fixation ; Forage legume ; Rhizobium spp.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In 1993 and 1994, 12 bacterial isolates were isolated from root nodules of cicer milkvetch (Astragalus cicer). In the tests for nodulation of A. cicer by these bacterial isolates, five were found to form hypertrophic structures, while only two formed true nodules. These true nodules were formed in a sterilized soil system. This system might be able to act as a DNA donor to provide residual DNA to other microbes in the soil. The rhizobial isolates were thought to have lost genetic material crucial to nodulation during the isolation process. This hypothesis was supported by an experiment in which isolate B2 was able to nodulate A. cicer in vermiculite culture after being mixed with heat-killed rhizobia, Rhizobium leguminosarum bv. trifolii and R. loti. The nodulation would not occur in vermiculite culture system without the heat-killed rhizobia. Based on the biochemical data, the B2 and 9462L, which formed true nodules with A. cicer, were closely related. The rhizobia type cultures that nodulate A. cicer include Bradyrhizobium japonicum, Rhizobium leguminosarum bv. trifolii, R. leguminosarum bv. viceae, and R. loti. All of these rhizobia were from different cross-inoculation groups. The B2 and 9462L isolates could only nodulate Medicago sativa, Phaseolus vulgaris, and Melilotus officinalis, but not these species within the genus from which they were isolated: Astragalus. The traditional cross-inoculation group concept obviously does not fit well in the classification of rhizobia associated with Astragalus. The rhizobia isolated from A. cicer can be quite different, and the rhizobia able to renodulate A. cicer also quite diverse.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003740050299
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 17
    Electronic Resource
    Electronic Resource
    Impact of nodule damage by Rivellia angulata on N2-fixation, growth, and yield of pigeonpea (Cajanus cajan L. Millsp.) grown in a Vertisol (1989)
    Springer
    Biology and fertility of soils 7 (1989), S. 95-100 
    Details
    ISSN: 1432-0789
    Keywords: Nodule damage ; Rivellia angulata ; Nitrogen fixation ; Cajanus cajan ; Pigeonpea ; Vertisol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Damage caused by Rivellia angulata larvae to pigeonpea root nodules at the ICRISAT center in India was greater in the crop grown on Vertisols (up to 86%) compared to that on Alfisols (20%). Attempts to quantify the field effects of nodule damage on growth and yield of pigeonpea in a Vertisol, involving many heavy applications of soil insecticides (aldrin and hexachlorocyclohexane) failed because the insecticides did not control the pest and adversely affected the growth of the pigeonpea and the subsequent crop of sorghum (Sorgorum bicolor L. Moench). The impact of nodule damage on pigeonpea growth, yield and nutrient uptake was successfully studied in greenhouse-grown plants at three N levels. In this pot study, artificial inoculation with Rivellia sp. led to substantial nodule damage (70%). The results of this damage were a significant overall reduction in nodule dry weight (46%), acetylene reduction activity (31%), total leaf area (36%), chlorophyll content of leaves (39%) and shoot dry weight (23%) 68 days after sowing. At maturity, Rivellia sp. infestation caused significant reductions in top dry weight (22%), root and nodule dry weight (27%), seed dry weight (14%), and total N (29%) and P uptake (19%). The problems and prospects of manipulating nodule damage so as to reduce N losses in pigeonpea are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00292565
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 18
    Electronic Resource
    Electronic Resource
    Yield response of spring wheat cultivars (Triticum aestivum and T. turgidum) to inoculation with Azospirillum brasilense under field conditions (1987)
    Springer
    Biology and fertility of soils 4 (1987), S. 27-35 
    Details
    ISSN: 1432-0789
    Keywords: Triticum aestivum ; T. turgidum ; Nitrogen fixation ; Field inoculation ; Acetylene reduction assay (ARA)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Eight commercial Israeli spring wheat cultivars (six Triticum aestivum and two T. turgidum) grown with 40 and 120 kg N/ha were tested for responses to inoculation with Azospirillum brasilense. At the low level of N fertilization (40 kg/ha), five cultivars showed significant increases in plant dry weight measured at the milky ripe stage; however, by maturation only the cultivar “Miriam” showed a significant increase in grain yield. Two cultivars, which had shown a positive inoculation effect at the earlier stages, had a significant decrease in grain yield. No significant effect of inoculation was found at the high N level. To confirm those results, four wheat (T. aestivum) cultivars were tested separately over 4 years in 4 different locations under varying N levels. Only Miriam showed a consistently positive effect of Azospirillum inoculation on grain yield. Inoculation increased the number of roots per plant on Miriam compared with uninoculated plants. This effect was found at all N levels. Nutrient (N, P and K) accumulation and number of fertile tillers per unit area were also enhanced by Azospirillum, but these parameters were greatly affected by the level of applied N. It is suggested that the positive response of the spring wheat cultivar “Miriam” to Azospirillum inoculation is due to its capacity to escape water stresses at the end of the growth season.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00280347
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 19
    Electronic Resource
    Electronic Resource
    Nitrogen fixation and balance studies of rice soil (1987)
    Springer
    Biology and fertility of soils 4 (1987), S. 15-19 
    Details
    ISSN: 1432-0789
    Keywords: Nitrogen fixation ; N-balance studies ; Azolla ; Blue-green algae ; Chemical N fertilization ; Rice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A nitrogen balance study conducted in ceramic pots under net house conditions for four seasons showed that flooded rice soil leaves a positive nitrogen balance (N increase) in soil after rice cropping in both fertilized and unfertilized soil. Recovery of nitrogen from rice soil was more than its input in unfertilized soil, but it was reverse in fertilized soil. Incorporation of Azolla or BGA twice as basal and 20 days after transplanting (DAT) alone or in combination showed higher nitrogen balance and N2-fixation (N gain) in soil than in that where it was applied once either as basal or 20 DAT. Planted soil showed more N2-fixation than that of fallow rice, and flooded soil fixed more nitrogen in comparison to non-flooded soil in light but less in dark. Soil exposed to light fixed more nitrogen than that of unexposed soil in both flooded and non-flooded conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00280345
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 20
    Electronic Resource
    Electronic Resource
    Stimulation of root exudation of rice seedlings by Azospirillum strains: carbon budget under gnotobiotic conditions (1987)
    Springer
    Biology and fertility of soils 4 (1987), S. 9-14 
    Details
    ISSN: 1432-0789
    Keywords: Rhizosphere ; Nitrogen fixation ; Root exudates ; Soil bacteria ; Carbon budget ; Rice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The association of rice seedlings (cv. Delta) with different strains of Azospirillum was studied under monoxenic conditions in the dark. Axenic 3-day-old seedlings were obtained on a C- and N-free medium and inoculated with 6 · 107 bacteria per plant in a closed vial. Seven days later, different components of a carbon budget were evaluated on them and on sterile controls: respired CO2, carbon of shoot and roots, bacterial and soluble carbon in the medium. Two strains (A. lipoferum 4B and A. brasilense A95) isolated from the rhizosphere of rice caused an increase in exudation, + 36% and + 17% respectively compared with sterile control. Shoot carbon incorporation and respiration were reduced by inoculation. A third strain (A. brasilense R07) caused no significant change in exudation. A. lipoferum B7C isolated from maize did not stimulate rice exudation either. We further investigated a possible effect of nitrogen fixation on this phenomenon: inhibition of nitrogen fixation by 10% C2H2 did not modify the extent of C exudation by rice associated with A. lipoferum 4B or with the non-motile A. lipoferum 4T.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00280344
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 21
    Electronic Resource
    Electronic Resource
    Dual inoculation with strains of Bradyrhizobium japonicum and Azospirillum brasilense to improve growth and biological nitrogen fixation of soybean (Glycine max L.) (1997)
    Springer
    Biology and fertility of soils 24 (1997), S. 317-322 
    Details
    ISSN: 1432-0789
    Keywords: Key words Soybean ; Isotope dilution ; Nitrogen fixation ; Bradyrhizobium japonicum ; Soil sterilization ; 15N ; Azospirillum brasilense ; Bacterial inoculation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effects of inoculation with Bradyrhizobium japonicum and Azospirillum brasilense strains on the growth of soybean were evaluated with regard to the estimation of N2 fixation using the 15N isotope dilution technique. Inoculation, in general, increased the dry mass of soybean as well as nitrogen content. Dual inoculation with a mixture of B. japonicum and A. brasilense strains was superior over single inoculation with B. japonicum. Nitrogen fixed (Ndfa) varied according to inoculant and soil conditions. Percentages of nitrogen derived from air (% Ndfa) using a non-nodulating isoline were 72% and 76% for B. japonicum and B. japonicum plus A. brasilense, respectively, in non-sterile soil. A similar but higher trend was recorded in sterilized soil, in which the percentages of N2 fixed were 81% and 86% for single and dual inoculation, respectively. The correlation coefficient between N2 fixed and N uptake (r=0.94) and dry mass (r=0.89) was significant. Application of special bacterial inoculants in agricultural systems of Egypt seems to be a promising technology and could be used for improving soybean growth as well as soil fertility, thus minimizing environmental pollution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003740050250
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 22
    Electronic Resource
    Electronic Resource
    Influence of long-term conservation tillage on soil and rhizosphere microorganisms (1999)
    Springer
    Biology and fertility of soils 29 (1999), S. 81-86 
    Details
    ISSN: 1432-0789
    Keywords: Key words Soil tillage ; Rhizosphere microorganisms ; Cereals ; Nitrogen fixation ; Gaeumanomyces graminis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  In long-term field experiments on sandy loam and loamy sand soils, the influence of conservation and conventional tillage on soil and rhizosphere microorganisms was studied. Conservation tillage stimulated rhizosphere bacteria on winter wheat, winter barley, winter rye and maize in different soil layers. Particularly the populations of Agrobacterium spp. and Pseudomonas spp. were increased. On the sandy loam, N2 fixation and nodulation of pea plants were significantly increased. No influence of different soil tillage was determined on the colonization of the rhizosphere by mycorrhiza and saprophytic fungi. Stubble residues infected with Gaeumanomyces graminis were infectious for a longer time on the soil surface than after incorporation into the soil.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003740050528
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 23
    Electronic Resource
    Electronic Resource
    Fate of blue-green algae in the food web of flooded rice-field ecosystems (1999)
    Springer
    Biology and fertility of soils 29 (1999), S. 141-145 
    Details
    ISSN: 1432-0789
    Keywords: Key words Blue-green algae ; Nitrogen fixation ; Rice ecosystem ; Zooplankton ; Benthos
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  As part of an integrated pest management project to study the role blue-green algae (BGA) may play in the food web of rice-field ecosystems, 14C-labelled filamentous and monocellular BGA were used as food for fish, zooplankton and benthic fauna in artificial rice fields in the form of three aquaria. 14C present in the organisms was then traced by liquid scintillation to follow the manner in which the labelled BGA were consumed by different organisms. In this study the grazing rate of fish (mud carp) was compared to that of benthic organisms and zooplankton. It was found that fish consumed the BGA at the fastest rates and in the largest amounts, followed by the benthic species and zooplankton. It was also found that filamentous BGA were consumed in higher amounts than monocellular BGA. The importance of grazing in nutrient recycling is emphasized.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003740050536
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 24
    Electronic Resource
    Electronic Resource
    Diurnal and seasonal patterns of nitrogenase activity of red alder in comparison with white clover in silvopastoral agroforestry systems (1999)
    Springer
    Biology and fertility of soils 28 (1999), S. 267-270 
    Details
    ISSN: 1432-0789
    Keywords: Key words Red alder ; White clover ; Nitrogenase activity ; Acetylene reduction assay ; Nitrogen fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  Simultaneous measurements were made to assess the diurnal and seasonal patterns of nitrogenase activity of red alder (Alnus rubra Bong.) and white clover (Trifolium repens L.) growing together in a silvopastoral agroforestry system using the acetylene reduction assay. Diurnal measurements were made in the summer and autumn at 3-h intervals whereas seasonal nitrogenase activity was assessed based on observations made at midday in July, September and January to represent the summer, autumn and winter seasons, respectively. No obvious diurnal patterns of nitrogenase activity were found in either red alder or white clover in summer and no significant variations in nitrogenase activity were observed between day and night. However, in autumn, pronounced diurnal patterns were observed in both species. Significantly higher rates of nitrogenase activity per unit dry weigh (dwt) of nodules were detected at 1500 hours in red alder, whereas, in white clover, significantly higher rates were obtained at 2100 hours. There was no significant correlation between diurnal nitrogenase activity and air temperature, photosynthetically active radiation and soil temperature at 10 cm depth in either red alder or white clover. Seasonal rates of nitrogenase activity showed significantly higher activity in summer, which subsequently decreased in autumn, to reach very low levels in the winter. The rates of nitrogenase activity of white clover were consistently higher than those of red alder both diurnally and seasonally. In the three seasons sampled, the average nitrogenase activity for white clover was 66.42 μmol C2H4 g dwt–1 h–1, which was 3.5 times higher than the 18.67 μmol C2H4 g dwt–1 h–1 obtained for red alder.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003740050492
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 25
    Electronic Resource
    Electronic Resource
    Relationships between soil aggregation and mycorrhizae as influenced by soil biota and nitrogen nutrition (1999)
    Springer
    Biology and fertility of soils 28 (1999), S. 356-363 
    Details
    ISSN: 1432-0789
    Keywords: Key words Arbuscular mycorrhiza ; Collembola ; Nitrogen fertilization ; Nitrogen fixation ; Soil aggregation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  The effect of the form of N nutrition on soil stability is an important consideration for the management of sustainable agricultural systems. We grew soybean [Glycine max (L.) Merr.] plants in pot cultures in unsterilized soil, and treated them by (1) inoculating them with Bradyrhizobium japonicum, fertilizing with (2) nitrate or (3) ammonia, or (4) by providing only minimum N amendment for the controls. The soils were sampled at 3-week intervals to determine changes in water-stable soil aggregates (WSA), soil pH, the development of roots, arbuscular mycorrhizal (AM) soil and root colonization, and selected functional groups of soil bacteria. The soil fauna was assayed at the end of the experiment (9 weeks). WSA was correlated positively with root and AM soil mycelium development, but negatively with total bacterial counts. Soil arthropod (Collembola) numbers were negatively correlated with AM hyphal length. Soils of nodulated and ammonia-fertilized plants had the highest levels of WSA and the lowest pH at week 9. Sparse root development in the soils of the N-deficient, control plants indicated that WSA formation was primarily influenced by AM hyphae. The ratio of bacterial counts in the water-stable versus water-unstable soil fractions increased for the first 6 weeks and then declined, while counts of anaerobic bacteria increased with increasing WSA. The numbers of soil invertebrates (nematodes) and protozoans did not correlate with bacterial counts or AM soil-hyphal lengths. Soil pH did not affect mycorrhiza development, but actinomycete counts declined with decreasing soil pH. AM fungi and roots interacted as the factors that affect soil aggregation, regardless of N nutrition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003740050504
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 26
    Electronic Resource
    Electronic Resource
    Adaptation of green manure legumes to adverse conditions in rice lowlands (1996)
    Springer
    Biology and fertility of soils 23 (1996), S. 243-248 
    Details
    ISSN: 1432-0789
    Keywords: Key words Adverse soil conditons ; Aeschynomene ; Green manure ; Lowland rice ; Nitrogen fixation ; Sesbania ; Forming system development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Poor adoption of sustainable pre-rice green manure technology by lowland farmers is frequently associated with unreliable legume performance under adverse environmental conditions such as marginal soils, short photoperiod, and unfavorable hydrology. A series of field and microplot experiments were conducted at the International Rice Research Institute (IRRI) in 1991 and 1992 to screen and evaluate 12 promising flood-tolerant legumes for adaptation (N accumulation and biological N2 fixation) to a range of environmental stresses, frequently encountered in rice lowlands. Legumes belonging to the genera Sesbania and Aeschynomene were grown for 8 weeks at 10×10 cm spacing: (1) in a fertile control soil and in four marginally productive irrigated lowland rice soils (sandy Entisol, P-deficient Inceptisol, acid Ultisol, and saline Mollisol); (2) during short- (11.7 h) and long-day (12.3 h) seasons in a favorable irrigated lowland soil; and (3) in an aerobic soil (drought-prone rain-fed lowland) and a deep-flood-prone lowland soil (1 week seedling submergence). A large variability in N accumulation was observed among legume species and across different environments, ranging from less than 1 to over 70 mg N plant–1. The nitrogen derived from the atmosphere (Ndfa) accounted on average for 82% of total N accumulation. Sesbania virgata was least affected by unfavorable soil conditions but its Ndfa was the lowest among the tested species (less than 60%). Stem nodule formation did not convey a significant advantage to legumes grown under adverse soil conditions. However, flooding reduced N2 fixation less in stem-nodulating than in solely root-nodulating species. Most species drastically reduced N accumulation under short-day conditions. Aeschynomene afraspera and S. speciosa were least affected by photoperiod. The considerable genetic variability in the germplasm screened allows the selection of potentially appropriate legumes to most conditions studied, thus increasing N accumulation in green manures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00335951
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 27
    Electronic Resource
    Electronic Resource
    Soil surface disturbances in cold deserts: effects on nitrogenase activity in cyanobacterial-lichen soil crusts (1996)
    Springer
    Biology and fertility of soils 23 (1996), S. 362-367 
    Details
    ISSN: 1432-0789
    Keywords: Cryptobiotic ; Cryptogamic ; Microphytic ; Microbiotic ; Deserts ; Nitrogen fixation ; Nutrient cycling ; Lichens ; Microcoleus vaginatus ; Collema tenax ; Heterocysts ; Acetylene reduction assay ; ARA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Cyanobacterial-lichen soil crusts can be a dominant source of nitrogen for cold-desert ecosystems. Effects of surface disturbance from footprints, bike and vehicle tracks on the nitrogenase activity in these crusts was investigated. Surface disturbances reduced nitrogenase activity by 30–100%. Crusts dominated by the cyanobacterium Microcoleus vaginatus on sandy soils were the most susceptible to disruption; crusts on gypsiferous soils were the least susceptible. Crusts where the soil lichen Collema tenax was present showed less immediate effects; however, nitrogenase activity still declined over time. Levels of nitrogenase activity reduction were affected by the degree of soil disruption and whether sites were dominated by cyanobacteria with or without heterocysts. Consequently, anthropogenic surface disturbances may have serious implications for nitrogen budgets in these ecosystems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00335908
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 28
    Electronic Resource
    Electronic Resource
    Soil surface disturbances in cold deserts: effects on nitrogenase activity in cyanobacterial-lichen soil crusts (1996)
    Springer
    Biology and fertility of soils 23 (1996), S. 362-367 
    Details
    ISSN: 1432-0789
    Keywords: Key words Cryptobiotic ; Cryptogamic ; Microphytic ; Microbiotic ; Deserts ; Nitrogen fixation ; Nutrient ; cycling ; Lichens ; Microcoleus vaginatus ; Collema tenax ; Heterocysts ; Acetylene reduction assay ; ARA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Cyanobacterial-lichen soil crusts can be a dominant source of nitrogen for cold-desert ecosystems. Effects of surface disturbance from footprints, bike and vehicle tracks on the nitrogenase activity in these crusts was investigated. Surface disturbances reduced nitrogenase activity by 30–100%. Crusts dominated by the cyanobacterium Microcoleus vaginatus on sandy soils were the most susceptible to disruption; crusts on gypsiferous soils were the least susceptible. Crusts where the soil lichen Collema tenax was present showed less immediate effects; however, nitrogenase activity still declined over time. Levels of nitrogenase activity reduction were affected by the degree of soil disruption and whether sites were dominated by cyanobacteria with or without heterocysts. Consequently, anthropogenic surface disturbances may have serious implications for nitrogen budgets in these ecosystems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003740050184
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 29
    Electronic Resource
    Electronic Resource
    Survival and symbiotic properties of Bradyrhizobium japonicum in the presence of thiram: isolation of fungicide resistant strains (1997)
    Springer
    Biology and fertility of soils 26 (1997), S. 141-145 
    Details
    ISSN: 1432-0789
    Keywords: Key wordsBradyrhizobium japonicum ; Nodulation ; Nitrogen fixation ; Soybean ; Thiram
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The fungicide thiram, widely used as a chemical seed protectant, induces a strong inhibition of primary nodulation in the crown zone of soybean roots. The present work reports on the isolation of Bradyrhizobium japonicum strains resistant to thiram, some of which (T3B, A86 and A2) maintained their capacity for nodulation and were still efficient symbionts, but some (A1, C1 and C6) lost the ability to stimulate nodulation. Characterization tests such as growth at different pH, denitrifying ability, salt tolerance, production of siderophores and phosphate solubilization were performed on the resistant strains. Inoculants produced from these strains could be appropriate for use with thiram-treated seeds, without causing a loss of bacteria viability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003740050357
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 30
    Electronic Resource
    Electronic Resource
    Natural abundance of 15N in sweet potato, pumpkin, sorghum and castor bean: possible input of N2-derived nitrogen in sweet potato (1997)
    Springer
    Biology and fertility of soils 26 (1997), S. 152-154 
    Details
    ISSN: 1432-0789
    Keywords: Key wordsCucurbita moschata ; Ipomoea batatas ; Nitrogen fixation ; δ15N method ; Sorghum bicolor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Two combinations of plant species, sweet potato (three cultivars) and pumpkin, and sweet sorghum (three cultivars) and castor bean were grown separately in three plots of alluvial soil from June to September 1996. The shoots (leaves plus stems) of sweet potato and pumpkin, and the whole tops (leaves plus stems and grains) of sweet sorghum and castor bean were harvested twice, once in August and once in September in order to analyze their natural abundance of 15N (δ15N). The δ15N values of two of the varieties of sweet potato harvested in September were significantly lower than those of pumpkin, while δ15N values of sweet potato and pumpkin harvested in August, as well as those of sweet sorghum and castor bean harvested in August and September, did not significantly differ. The lower δ15N values observed in the September-harvested sweet potato may indicate that as much as 40% of the N intake of this species is derived from dinitrogen. This species is known to have a high ability to take up N from undefined sources.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003740050359
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 31
    Electronic Resource
    Electronic Resource
    Adaptation of green manure legumes to adverse conditions in rice lowlands (1996)
    Springer
    Biology and fertility of soils 23 (1996), S. 243-248 
    Details
    ISSN: 1432-0789
    Keywords: Adverse soil conditons ; Aeschynomene ; Green manure ; Lowland rice ; Nitrogen fixation ; Sesbania ; Forming system development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Poor adoption of sustainable pre-rice green manure technology by lowland farmers is frequently associated with unreliable legume performance under adverse environmental conditions such as marginal soils, short photoperiod, and unfavorable hydrology. A series of field and microplot experiments were conducted at the International Rice Research Institute (IRRI) in 1991 and 1992 to screen and evaluate 12 promising flood-tolerant legumes for adaptation (N accumulation and biological N2 fixation) to a range of environmental stresses, frequently encountered in rice lowlands. Legumes belonging to the genera Sesbania and Aeschynomene were grown for 8 weeks at 10×10 cm spacing: (1) in a fertile control soil and in four marginally productive irrigated lowland rice soils (sandy Entisol, P-deficient Inceptisol, acid Ultisol, and saline Mollisol); (2) during short- (11.7h) and long-day (12.3 h) seasons in a favorable irrigated lowland soil; and (3) in an aerobic soil (drought-prone rain-fed lowland) and a deep-flood-prone lowland soil (1 week seedling submergence). A large variability in N accumulation was obsersed among legume species and across different environments, ranging from less than 1 to over 70 mg N plant-1. The nitrogen derived from the atmosphere (Ndfa) accounted on average for 82% of total N accumulation. Sesbania virgata was least affected by unfavorable soil conditions but its Ndfa was the lowest among the tested species (less than 60%). Stem nodule formation did not convey a significant advantage to legumes grown under adverse soil conditions. However, flooding reduced N2 fixation less in stem-nodulating than in solely root-nodulating species. Most species drastically reduced N accumulation under short-day conditions. Aeschynomene afraspera and S. speciosa were least affected by photoperiod. The considerable genetic variability in the germplasm screened allows the selection of potentially appropriate legumes to most conditions studied, thus increasing N accumulation in green manures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00335951
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 32
    Electronic Resource
    Electronic Resource
    Nitrogen use in maize-grain legume cropping systems in semi-arid Kenya (1995)
    Springer
    Biology and fertility of soils 20 (1995), S. 57-62 
    Details
    ISSN: 1432-0789
    Keywords: Nitrogen use ; Nitrogen fertilizer recovery ; Zea mays ; Phaseolus vulgaris ; Vigna unguiculata ; Nitrogen fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Locally suitable cultivars of maize, beans, and cowpeas were grown in field experiments for four seasons in semi-arid Kenya. For three seasons, the dry matter production and grain yield of maize and beans were not increased by N fertilizer additions up to 120 kg N ha-1. Fertilizer recoveries measured by 15N isotope dilution techniques were low, less than 20%. Inoculated and uninoculated beans failed to fix N2. By contrast the cowpea derived 50% of its N from fixation, equivalent to 197 kg N ha-1. The N content of the grain generally exceeded 40 kg N ha-1, and the N content of the seeds from the grain legumes were greater than those from the cereals. Large inputs of N fertilizer or N by fixation are required if maize-grain legume cropping system in semiarid Kenya are to be sustained in the long term.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307842
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 33
    Electronic Resource
    Electronic Resource
    Nodulation of African yam bean (Sphenostylis stenocarpa) by Bradyrhizobium sp. isolated from Erythrina brucei (1997)
    Springer
    Biology and fertility of soils 25 (1997), S. 209-210 
    Details
    ISSN: 1432-0789
    Keywords: Key wordsBradyrhizobium ; Sphenostylis stenocarpa ; Nitrogen fixation ; Soil reclamation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract African yam bean (Sphenostylis stenocarpa), which is widely cultivated in Africa because of its growth capability on marginal soils, was nodulated by an endosymbiont (characterized and designed Bradyrhizobium sp. AUEB20) isolated from the Ethiopian tree Erythrina brucei with the formation of a small number of large, indeterminate N2-fixing nodules. In contrast, 24 other isolates from Ethiopian woody legumes were ineffective. Strain AUEB20 promiscuously nodulated a number of tropical legumes, but none out of five European crop plants tested.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003740050305
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 34
    Electronic Resource
    Electronic Resource
    Diversity, adaptation and activity of the bacterial flora in saline environments (1997)
    Springer
    Biology and fertility of soils 25 (1997), S. 211-223 
    Details
    ISSN: 1432-0789
    Keywords: Key words Bacterial flora ; Salt-affected soils ; Salt marshes ; Osmotic adjustment ; Microbial activity ; Nitrogen fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Saline environments have a natural bacterial flora, which may play a significant role in the economy of these habitats. The natural saline environments (usually containing salinity equivalent to 4–30% NaCl) are aquatic (e.g. salt marshes) or terrestrial (e.g. saline lands). Saline environments include an increasing area of salt-affected cultivated soils throughout the world. These environments contain various ions which may interfere with uptake of water and which may be toxic to a large number of organisms. Saline environments harbour taxonomically diverse bacterial groups, which exhibit modified physiological and structural characteristics under the prevailing saline conditions. The majority of these bacteria can osmoregulate by synthesizing specific compatible organic osmolytes such as glutamine, proline and glycine betaine and a few of them accumulate inorganic solutes such as Na+, K+ and Mg2+. The morphology of the bacteria is usually modified, cells are usually elongated, swollen and showing shrinkage, in addition to changes in the cell and cytoplasmic volume. The chemical composition of membranes may also occasionally be modified, and the synthesis pattern of proteins, lipids, fatty acids and polysaccharides may change with a moderate increase in salinity. However, ultrastructural alterations in cells of halophilic bacteria have not been reported, and profound changes in cellular properties of these bacteria only occur at concentrations above 2MNaCl. Evidence has accumulated that the bacteria are essential elements in the saline environment because of their activity such as degradation of plant remains, nitrogen fixation and production of active metabolites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003740050306
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 35
    Electronic Resource
    Electronic Resource
    Variation in nitrogen fixation among populations ofFrankia sp. andCeanothus sp. in actinorhizal association (1989)
    Springer
    Biology and fertility of soils 7 (1989), S. 269-274 
    Details
    ISSN: 1432-0789
    Keywords: Nitrogen fixation ; Frankia-Ceanothus spp. association ; Acetylene reduction assay (ARA) ; Microsymbiont population ; Nodules ; Actinomycetes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Wildland shrub improvement is needed for sound range and disturbed land revegetation practice. The possibility of selecting superior N2-fixingFrankia-Ceanothus spp. actinorhizal associations was examined. Greenhouse tests were used to expose various soil-borne microsymbiont andCeanothus sp. population accessions in reciprocal combination. The acetylene reduction rate was used as a measure of N2-fixation capacity. There was no significant interaction between host and microsymbiont regardless of source for all variables measured. The acetylene reduction rate, nodule number and mass, plant biomass, and root: shoot ratio were significantly different among soil sources. The acetylene reduction rate was not significantly different amongCeanothus sp. accessions. Neither was it strongly correlated with other variables. It was concluded that the N2-fixation rate is more a function ofFrankia sp. than the hostCeanothus sp. in actinorhizal associations. It appears possible to select soil sources with superior N2-fixing microsymbiont populations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00709660
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 36
    Electronic Resource
    Electronic Resource
    Seeding vs. vegetative propagations of the stem-nodulating green manure Sesbania rostrata (1988)
    Springer
    Biology and fertility of soils 6 (1988), S. 279-281 
    Details
    ISSN: 1432-0789
    Keywords: Sesbania rostrata ; Green manure ; Biofertilizer ; Nitrogen fixation ; Stem nodule
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Ratooning and stem cutting were compared with seeding in order to reduce the amount of seeds of Sesbania rostrata for green-manure growth. Both methods increased the biofertilizer yield highly significantly within a 6-week growth period.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00261012
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 37
    Electronic Resource
    Electronic Resource
    The evolution of a plant globin gene family (1984)
    Springer
    Journal of molecular evolution 21 (1984), S. 19-32 
    Details
    ISSN: 1432-1432
    Keywords: Leghemoglobin ; Gene duplication ; Gene linkage ; Concerted evolution ; Nitrogen fixation ; Soybean
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have analyzed the sequences of soybean leghemoglobin genes as an initial step toward understanding their mode of evolution. Alignment of the sequences of plant globin genes with those of animals reveals that (i) based on the proportion of nucleotide substitutions that have occurred at the first, second, and third codon positions, the time of divergence of plant and animal globin gene families appears to be extremely remote (between 900 million and 1.4 billion years ago, if one assumes constancy of evolutionary rate in both the plant and animal lineages) and (ii) in addition to the normal regulatory sequences on the 5′ end, an approximately 30-base-pair sequence, specific to globin genes, that surrounds the cap site is conserved between the plant and animal globin genes. Comparison of the leghemoglobin sequences with one another shows that (i) the relative amount of sequence divergence in various coding and noncoding regions is roughly similar to that found for animal globin genes and (ii) as in animal globin genes, the positions of insertions and deletions in the intervening sequences often coincide with the locations of direct repeats. Thus, the mode of evolution of the plant globin genes appears to resemble, in many ways, that of their animal counterparts. We contrast the overall intergenic organization of the plant globin genes with that of animal genes, and discuss the possibility of the concerted evolution of the leghemoglobin genes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02100624
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 38
    Electronic Resource
    Electronic Resource
    Free-radical-induced mutation vs redox regulation: Costs and benefits of genes in organelles (1996)
    Springer
    Journal of molecular evolution 42 (1996), S. 482-492 
    Details
    ISSN: 1432-1432
    Keywords: Aging ; Chloroplasts ; Mitochondria ; Cell evolution ; Cytoplasmic genomes ; Gene transfer ; Redox regulation ; Free radical mutagenesis ; Nitrogen fixation ; Endosymbiosis ; Mutation frequency ; Uniparental inheritance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The prokaryotic endosymbionts that became plastids and mitochondria contained genes destined for one of three fates. Genes required for free-living existence were lost. Most genes useful to the symbiosis were transferred to the nucleus of the host. Some genes, a small minority, were retained within the organelle. Here we suggest that a selective advantage of movement of genes to the nucleus is decreased mutation: plastids and mitochondria have high volume-specific rates of redox reactions, producing oxygen free radicals that chemically modify DNA. These mutations lead to synthesis of modified electron carriers that in turn generate more mutagenic free radicals—the “vicious circle” theory of aging. Transfer of genes to the nucleus is also advantageous in facilitating sexual recombination and DNA repair. For genes encoding certain key components of photosynthesis and respiration, direct control of gene expression by redox state of electron carriers may be required to minimize free radical production, providing a selective advantage of organelle location which outweighs that of location in the nucleus. A previous proposal for transfer of genes to the nucleus is an economy of resources in having a single genome and a single apparatus for gene expression, but this argument fails if any organellar gene is retained. A previous proposal for the retention of genes within organelles is that certain proteins are organelle-encoded because they cannot be imported, but there is now evidence against this view. Decreased free radical mutagenesis and increased sexual recombination upon transfer to the nucleus together with redox control of gene expression in organelles may now account for the slightly different gene distributions among nuclei, plastids, and mitochondria found in major eukaryote taxa. This analysis suggests a novel reason for uniparental inheritance of organelles and the evolution of anisogametic sex, and may also account for the occurrence of nitrogen fixation in symbionts rather than in nitrogen-fixing organelles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02352278
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 39
    Electronic Resource
    Electronic Resource
    Plant growth, leaf water potential, nitrogenase activity and nodule anatomy in Leucaena leucocephala as affected by water stress and nitrogen availability (1997)
    Springer
    Trees 12 (1997), S. 42-48 
    Details
    ISSN: 0931-1890
    Keywords: Key words Drought stress ; Fertilization ; Irrigation ; Nitrogen fixation ; Nodule structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  The effects of water stress and nitrogen availability on leaf water potential, nitrogenase activity, and growth was studied in a pot experiment with Leucaena leucocephala seedlings. Water stress was imposed on fertilized and unfertilized plants after inoculation with Rhizobium. Non-inoculated seedlings were used as control plants. Water stress lowered leaf water potential in all seedlings after 14 days of treatment. In inoculated seedlings, fertilized plants were more sensitive to water stress than unfertilized plants, as shown by a higher leaf water potential in plants of the latter treatment. Uninoculated and fertilized seedlings were most affected by water stress. This indicates that Rhizobium might increase stress tolerance in unfertilized seedlings at moderate water stress levels. The combined effects of water stress and applied fertilizers resulted in cessation of nitrogen fixation. Nitrogen fixation came to a complete stop after 22 days of water stress in fertilized seedlings. The different treatments were accompanied by anatomical changes of nodule structure. It is hypothesised that the leaf water potential may be used as an indicator to predict changes in nitrogen fixation in legume tree/shrub species during periods of water stress.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00009695
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 40
    Electronic Resource
    Electronic Resource
    Microclimatic parameters influencing nitrogen fixation in the phyllosphere in a Costa Rican premontane rain forest (1998)
    Springer
    Oecologia 117 (1998), S. 9-18 
    Details
    ISSN: 1432-1939
    Keywords: Key words Costa Rica ; Cyanobacteria ; Microclimate ; Nitrogen fixation ; Phyllosphere
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The acetylene reduction method was used to measure nitrogen fixation in the phyllosphere of attached leaves of different phorophytes under natural conditions in a premontane rain forest in Costa Rica. Maximum rates of nitrogen fixation (26 ng N · cm−2 leaf area · h−1) – mainly due to the activity of two species of Scytonema (Cyanobacteria) – were measured in the rainy season in bright sunlight. Rates of nitrogen fixation were correlated with the leaf area covered by Scytonema. In periods without precipitation the fixation activity decreased to zero within 2–3 days. As long as the epiphylls were sufficiently supplied with water, other microclimatic factors like temperature and light intensity also influenced nitrogen fixation rates, but to a lesser extent. Relative humidity and species of phorophyte showed no direct influence. It was concluded that the most important factor for nitrogen fixation in the phyllosphere was the availability of liquid water. Linking these results to meteorological data, the input of nitrogen by biological nitrogen fixation in the phyllosphere in the investigation area was estimated to be as much as 1.6 ± 0.8 kg N · ha−1 · year−1 per unit of leaf area index (LAI). For an LAI of 2 for the understory the nitrogen input would vary between 2 and 5 kg N · ha−1 · year−1. This work also demonstrates the importance of detailed knowledge of variation in microclimate throughout the year as a basis for extrapolation of the annual nitrogen input.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004420050625
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 41
    Electronic Resource
    Electronic Resource
    Ammonium effects on function and structure of nitrogen-fixing root nodules of Alnus incana (L.) Moench (1982)
    Springer
    Planta 156 (1982), S. 332-340 
    Details
    ISSN: 1432-2048
    Keywords: Alnus ; Ammonium ; Carbon translocation ; Endophyte damage ; Nitrogen fixation ; Root nodule
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cloned plants of Alnus incana (L.) Moench were inoculated and grown without combined nitrogen for seven weeks. The effects of ammonium on the function and structure of the root nodules were studied by adding 20 mM NH4Cl (20 mM KCl=control) for four days. Nitrogenase activity decreased to ca. 50% after one day and to less than 10% after two days in ammonium treated plants, but was unaffected in control plants. The results were similar at photon flux densities of 200 and 50 μmol m-2 s-1. At the higher light level the effect was concentration dependent between 2 and 20 mM NH4Cl. The recovery was slow, and more than 11 d were needed for plants treated with 20 mM ammonium to reach initial activity. The distribution of 14C to the root nodules after assimilation of 14CO2 by the plants was not changed by the ammonium treatment. Microscopical studies of root nodules showed high frequencies of endophyte vesicles being visually damaged in nodules from ammonium-treated plants, but not in nodules from control plants. When nitrogenase activity was restored, visually damaged vesicles were again few, whereas young developing vesicles were numerous. The slow recovery, the 14C-translocation pattern, and the structural changes of the endophyte indicate a more complex mechanism of ammonium influence than simply a short-term reduction in supply of carbon compounds to the nodules.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00397471
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 42
    Electronic Resource
    Electronic Resource
    Nitrogen nutrition and the development of biochemical functions associated with nitrogen fixation and ammonia assimilation of nodules on cowpea seedlings (1984)
    Springer
    Planta 162 (1984), S. 327-333 
    Details
    ISSN: 1432-2048
    Keywords: Ammonia ; Nitrogen fixation ; Nodule ; Senescence (root nodules) ; Ureide ; Vigna
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract During early development (up to 18 d after sowing) of nodules of an “effective” cowpea symbiosis (Vigna unguiculata (L.) Walp cv. Vita 3: Rhizobium strain CB756), rapidly increasing nitrogenase (EC 1.7.99.2) activity and leghaemoglobin content were accompanied by rapid increases in activities of glutamine synthetase (EC 6.3.1.2), glutamate synthase (EC 2.6.1.53), enzymes of denovo purine synthesis (forming inosine monophosphate) xanthine oxidoreductase (EC 1.2.3.2), urate oxidase (EC 1.7.3.3), phosphoenolpyruvate carboxylase (EC 4.1.1.31) and led to increased export of ureides (allantoin and allantoic acid) to the shoot of the host plant in the xylem. Culturing plants with the nodulated root systems maintained in the absence of N2 (in 80 Ar: 20 O2, v/v) had little effect on the rates of induction and increase in nitrogenase activity and leghaemoglobin content but, in the absence of N2 fixation and consequent ammonia production by bacteroids, there was no stimulation of activity of enzymes of ammonia assimilation or of the synthesis of purines or ureides. Addition of NO 3 - (0.1–0.2 mM) relieved host-plant nitrogen deficiency caused by the Ar: O2 treatment but failed to increase levels of enzymes of N metabolism in either the bacteroid or the plant-cell fractions of the nodule. Premature senescence in Ar: O2-grown nodules occurred at 18–20 d after sowing, and resulted in reduced levels of nitrogenase activity and leghaemoglobin but increased the activity of hydroxybutyrate oxidoreductase (EC 1.1.1.30).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00396744
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 43
    Electronic Resource
    Electronic Resource
    Production of gibberellins and indole-3-acetic acid by Rhizobium phaseoli in relation to nodulation of Phaseolus vulgaris roots (1988)
    Springer
    Planta 175 (1988), S. 532-538 
    Details
    ISSN: 1432-2048
    Keywords: Auxin (IAA), production by Rhizobium ; Gibberellin production by Rhizobium ; Mutant (Rhizobium) ; Nitrogen fixation ; Phaseolus (nodulation) ; Rhizobium (mutants) ; Root nodule
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Similar ranges of gibberellins (GAs) were detected by high-performance liquid chromatography (HPLC)-immunoassay procedures in ten cultures of wild-type and mutant strains of Rhizobium phaseoli. The major GAs excreted into the culture medium were GA1 and GA4. These identifications were confirmed by combined gas chromatographymass spectrometry. The HPLC-immunoassays also detected smaller amounts of GA9- as well as GA20-like compounds, the latter being present in some but not all cultures. In addition to GAs, all strains excreted indole-3-acetic acid (IAA) but there was no obvious relationship between the amounts of GA and IAA that accumulated. The Rhizobium strains studied included nod − and fix − mutants, making it unlikely that the IAA- and GA-biosynthesis genes are closely linked to the genes for nodulation and nitrogen fixation. The HPLC-immunoassay analyses showed also that nodules and non-nodulated roots of Phaseolus vulgaris L. contained similar spectra of GAs to R. phaseoli culture media. The GA pools in roots and nodules were of similar size, indicating that Rhizobium does not make a major contribution to the GA content of the infected tissue.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00393076
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 44
    Electronic Resource
    Electronic Resource
    The unique root-nodule symbiosis between Rhizobium and the aquatic legume, Neptunia natans (L. f.) Druce (1995)
    Springer
    Planta 196 (1995), S. 311-320 
    Details
    ISSN: 1432-2048
    Keywords: Infection ; Neptunia (root nodules) ; Nitrogen fixation ; Nodulation ; Rhizobium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We examined the development of the aquatic N2-fixing symbiosis between Rhizobium sp. (itNeptunia) and roots of Neptunia natans L. f. (Druce) (previously N. oleracea Lour.) under natural and laboratory conditions. When grown in its native marsh habitat, this unusual aquatic legume does not develop root hairs, the primary sites of rhizobial infection for most temperate legumes. Under natural conditions, the aquatic plant floats and develops nitrogen-fixing nodules at emergence of lateral roots on the primary root and on adventitious roots at stem nodes, but not from the stem itself. Cytological studies using various microscopies revealed that the mode of root infection involved an intercellular route of entry followed by an intracellular route of dissemination within nodule cells. After colonizing the root surface, the bacteria entered the primary root cortex through natural wounds caused by splitting of the epidermis and emergence of young lateral roots, and then stimulated early development of nodules at the base of such roots. The bacteria entered the nodule through pockets between separated host cells, then spread deeper in the nodule through a narrower intercellular route, and eventually evoked the formation of infection threads that penetrated host cells and spread throughout the nodule tissue. Bacteria were released from infection droplets at unwalled ends of infection threads, became enveloped by peribacteroid membranes, and transformed into enlarged bacteroids within symbiosomes. In older nodules, the bacteria within symbiosomes were embedded in an unusual, extensive fibrillar matrix. Cross-inoculation tests of 18 isolates of rhizobia from nodules of N. natans revealed a host specificity enabling effective nodulation of this aquatic legume, with lesser affinity for Medicago sativa and Ornithopus sp., and an inability to nodulate several other crop legume species. Acetylene reduction (N2 fixation) activity was detected in nodules of N. natans growing in aquatic habitats under natural conditions in Southern India. These studies indicate that a specific group of Rhizobium sp. (Neptunia) occupies a unique ecological niche in aquatic environments by entering into a N2-fixing root-nodule symbiosis with Neptunia natans.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00201390
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 45
    Electronic Resource
    Electronic Resource
    Subcellular organization of ureide biogenesis from glycolytic intermediates and ammonium in nitrogen-fixing soybean nodules (1982)
    Springer
    Planta 155 (1982), S. 45-51 
    Details
    ISSN: 1432-2048
    Keywords: Ammonium assimilation ; Glycine ; Nitrogen fixation ; Proplastid ; Purine synthesis ; Root nodule ; Ureide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Subcellular organelle fractionation of nitrogen-fixing nodules of soybean (Glycine max (L.) Merr.) indicates that a number of enzymes involved in the assimilation of ammonia into amino acids and purines are located in the proplastids. These include asparagine synthetase (EC 6.3.1.1), phosphoribosyl amidotransferase (EC 2.4.2.14), phosphoglycerate dehydrogenase (EC 1.1.1.95), serine hydroxymethylase (EC 2.1.2.1), and methylene-tetrahydrofolate dehydrogenase (EC 1.5.1.5). Of the two isoenzymes of asparate aminotransferase (EC 2.6.1.1) in the nodule, only one was located in the proplastid fraction. Both glutamate synthase (EC 1.4.1.14) and triosephosphate isomerase (EC 5.3.1.1) were associated at least in part with the proplastids. Glutamine synthetase (EC 6.3.1.2) and xanthine dehydrogenase (EC 1.2.1.37) were found in significant quantities only in the soluble fraction. Phosphoribosylpyrophosphate synthetase (EC 2.7.6.1) was found mostly in the soluble fraction, although small amounts of it were detected in other organelle fractions. These results together with recent organelle fractionation and electron microscopic studies form the basis for a model of the subcellular distribution of ammonium assimilation, amide synthesis and uredie biogenesis in the nodule.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00402930
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 46
    Electronic Resource
    Electronic Resource
    Pathways of assimilation and transfer of fixed nitrogen in coralloid roots of cycad-Nostoc symbioses (1988)
    Springer
    Planta 176 (1988), S. 461-471 
    Details
    ISSN: 1432-2048
    Keywords: Carbon dioxide fixation ; Citrulline ; Coralloid roots ; Cycads (nitrogen fixation) ; Nitrogen fixation ; Nitrogen transport ; Nostoc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Freshly detached coralloid roots of several cycad species were found to bleed spontaneously from xylem, permitting identification of products of nitrogen transfer from symbiotic organ to host. Structural features relevant to the export of fixed N were described for Macrozamia riedlei (Fisch. ex Gaud.) Gardn. the principal species studied. Citrulline (Cit), glutamine (Gln) and glutamic acid (Glu), the latter usually in a lesser amount, were the principal translocated solutes in Macrozamia (5 spp.), Encephalartos (4 spp.) and Lepidozamia (1 sp.), while Gln and a smaller amount of Glu, but no Cit were present in xylem sap of Bowenia (1 sp.),and Cycas (2 spp.). Time-course studies of 15N enrichment of the different tissue zones and the xylem sap of 15N2-pulse-fed coralloid roots of M. riedlei showed earlier 15N incorporation into Gln than into Cit, and a subsequent net decline in the 15N of Gln of the coralloid-root tissues, whereas Cit labeling continued to increase in inner cortex and stele and in the xylem sap. Hydrolysis of the 15N-labeled Cit and Gln consistently demonstrated much more intense labeling of the respective carbamyl and amide groups than of the other N-atoms. Coralloid roots of M. riedlei pulse-fed 14CO2 in darkness showed 14C labeling of aspartic acid (Asp) and Cit in all tissue zones and of Cit of xylem bleeding sap. Lateral roots and uninfected apogeotropic roots of M. riedlei and M. moorei also incorporated 14CO2 into Cit. The 14C of Cit was restricted to the carbamyl-C. Comparable 15N2 and CO2-feeding studies on corallid roots of Cycas revoluta showed Gln to be the dominant product of N2 fixation, with Asp and alanine as other major 14C-labeled amino compounds, but a total absence of Cit in labeled or unlabeled form.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00397652
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 47
    Electronic Resource
    Electronic Resource
    Effects of combined nitrogen on anapleurotic carbon assimilation and bleeding sap composition in Phaseolus vulgaris L. (1980)
    Springer
    Planta 148 (1980), S. 338-345 
    Details
    ISSN: 1432-2048
    Keywords: Allantoin ; Amino acids ; Bleeding sap ; Nitrogen fixation ; Phaseolus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Dwarf french beans, Phaseolus vulgaris L., were grown with or without inoculation with rhizobia (strain 3644), and with or without a combined nitrogen source (nitrate or ammonium ions). The distribution of radioactivity into products of dark 14CO2 assimilation was studied in roots or nodules from these plants. A detailed study was also made of the distribution and rates of excretion of nitrogen in xylem bleeding sap in 28 day old plants grown on the various sources of nitrogen. Whereas detached nodules accumulated radioactive glycine, serine and glutamate when incubated with 14CO2, bleeding sap from plants root fed 14CO2 contained low levels of radioactivity in these compounds but higher levels in allantoin. Chemical analysis showed allantoin to be the major compound transported in the xylem of nodulated plants, whether or not they were fed on combined nitrogen. In contrast uninoculated plants accumulated mainly amino acids in the bleeding sap, the amount and chemical composition of which depended on the combined nitrogen source.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00388121
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 48
    Electronic Resource
    Electronic Resource
    Effect of chemical inhibitors of photorespiration on nitrogenase activity in nodulated alfalfa plants (1980)
    Springer
    Planta 150 (1980), S. 299-302 
    Details
    ISSN: 1432-2048
    Keywords: Glyoxylate ; Isonicotinic acid hydracide ; Medicago ; Nitrogen fixation ; Photorespiration ; Rhizobium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Nitrogen fixation (measured as acetylene reduction) by whole nodulated alfalfa plants was stimulated when the plants were treated with isonicotinic acid hydracide (INH) and glyoxylate, both inhibitors of the glycolate pathway of carbohydrate metabolism, at concentrations of 300 and 100 mM, respectively. Reducing energetic loses caused by photorespiration results in an increase in the symbiotic nitrogen fixation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00384659
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 49
    Electronic Resource
    Electronic Resource
    15N2 Incorporation and metabolism in the lichen Peltigera aphthosa Willd (1981)
    Springer
    Planta 152 (1981), S. 544-552 
    Details
    ISSN: 1432-2048
    Keywords: Ammonium assimilation ; Lichens ; Nitrogen fixation ; Peltigera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The Nostoc in the cephalodia of the lichen Peltigera aphthosa Willd. fixed 15N2 and the bulk of the nitrogen fixed was continuously transferred from it to its eukaryotic partners (a fungus and a green alga, Coccomyxa sp.). Kinetic studies carried out over the first 30 min, after exposure of isolated cephalodia to 15N2, showed that highest initial 15N2-labelling was into NH 4 + . After 12 min little further increase in the NH 4 + label occurred while that in the amide group of glutamine and in glutamate continued to increase. The 15N-labelling of the amino group of glutamine and of aspartate increased more slowly, followed by an increase in the labelling of alanine. When total incorporation of 15N-label was calculated, the overall pattern was found to be rather similar except that, throughout the experiment, the total 15N incorporated into glutamate was about six times greater than that into the amide group of glutamine. Pulse chase experiments, in which 14N2 was added to cephalodia previously exposed to 15N2, showed that the NH 4 + pool rapidly became depleted of 15N-label, followed by decreases in the labelling of glutamate, the amide group of glutamine and aspartate. The 15N-labelling of alanine, however, continued to increase for a period. When isolated cephalodia were treated with L-methionine-SR-sulphoximine, an inhibitor of glutamine synthetase (EC 6.3.1.2), and azaserine, an inhibitor of glutamate synthase (EC 2.6.1.53), there was no detectable labelling in glutamine although the 15N-labelling of glutamate increased unimpaired. On treating the cephalodia with amino-oxyacetate, an inhibitor of aminotransferase activity, the alanine pool decreased. Evidence was obtained that glutamine synthetase and glutamate synthase were located in the Nostoc, and that glutamate dehydrogenase (EC 1.4.1.4) and various amino-transferases were located in the cephalodial fungus. Possible implications of these findings are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00380825
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 50
    Electronic Resource
    Electronic Resource
    Nitrogen fixation in the lichen Lobaria pulmonaria in elevated atmospheric carbon dioxide (1989)
    Springer
    Oecologia 79 (1989), S. 566-568 
    Details
    ISSN: 1432-1939
    Keywords: Carbon dioxide ; Lichen ; Lobaria ; Nitrogen fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Thalli of Lobaria pulmonaria (L.) Hoffm., a nitrogen-fixing epiphyte common in mesic temperate forests, were collected in a Douglas-fir (Pseudotsuga menziesii Franco) forest near Corvallis, Oregon, and maintained for 20 to 40 days in controlled-environment chambers with atmospheric CO2 concentrations of 374 and 700 μll-1. Nitrogenase activity, which was assayed by the acetylene reduction method, was approximately doubled in the lichen maintained in elevated CO2. Increases in nitrogen fixation by lichens may be an important part of the integrated ecosystem response to rising CO2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00378677
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 51
    Electronic Resource
    Electronic Resource
    The effects of nitrogen fixation, soil nitrate, and defoliation on the growth, alkaloids, and nitrogen levels of Lupinus succulentus (Fabaceae) (1987)
    Springer
    Oecologia 74 (1987), S. 425-431 
    Details
    ISSN: 1432-1939
    Keywords: Lupinus succulentus ; Fabaceae ; Lupine ; Quinolizidine alkaloids ; Nitrogen fixation ; Defoliation ; Plant-herbivore interactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We examined the effects of nitrogen nutrition and defoliation on the alkaloids, nitrogen levels, and growth of Lupinus succulentus by growing plants under five nitrogen/defoliation treatments: 1) fertilization with a high-nitrate nutrient solution, 2) fertilization with a low-nitrate solution, 3) inoculation with N-fixing bacteria but without available soil nitrogen, 4) high-nitrate solution plus periodic partial defoliation, and 5) low-nitrate plus defoliation. In the absence of defoliation, plants from both the N-fixing and high-N treatments had higher concentrations of alkaloids and nitrogen, and higher growth rates than the low-N plants. Periodic defoliation had little effect on the high-N plants, but defoliated N-fixing plants were severely stunted and had lower alkaloid and nitrogen levels. The experimental treatments also affected the relative concentrations of the alkaloids. Our results indicate that 1) alkaloid composition and concentration in L. succulentus are determined by both nitrogen availability and developmental state, 2) plants relying solely on N-fixation respond quite differently to defoliation than those with adequate soil nitrogen, and 3) the food value of the plant tissue can be affected by an interaction between the effects of defoliation and nitrogen status.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00378940
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 52
    Electronic Resource
    Electronic Resource
    Enhanced denitrification in plots of N2-fixing faba beans compared to plots of a non-fixing legume and non-legumes (1996)
    Springer
    Biology and fertility of soils 21 (1996), S. 77-83 
    Details
    ISSN: 1432-0789
    Keywords: Denitrification ; Field experiment ; Acetylene inhibition technique ; Nitrate ; Soil moisture ; Vicia faba ; Nitrogen fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Denitrification rates were studied using the C2H2 inhibition technique in a 2-year field experiment within plots of nodulated and non-nodulated faba beans, ryegrass, and cabbage. Denitrification rates ranged from 14.40 to 0.02 ng N2O−N g−1 soil dry weight h−1. Mean denitrification increased fourfold in plots of N2−fixing Vicia faba compared to non-nodulated V. faba mutant F48, Lolium perenne, and Brassica oleracea. The results with and without C2H2 treatment indicate that in the field the major part of this enhanced denitrification led to the endproduct N2 rather than to the ozone-degrading N2O. Higher denitrification rates of plots with N2−fixing plants in September seemed to be caused by an increase in soil NO inf3 sup- of about 20 kg ha−1 found between July and August. Soil NO inf3 sup- and soil moisture explained 67% of the variation in denitrification rates of the different soil samples over the growing seasons in the 2 years. Soil moisture explained 44% of the variation for soil planted with N2−fixing plants and 62% for soil planted with non-fixing plants. Positive exponential relationships were obtained between denitrification rates and soil nitrate (r=0.71) and soil moisture (r=0.82).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00335996
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 53
    Electronic Resource
    Electronic Resource
    Endophytic establishment of Azorhizobium caulinodans through auxin-induced root tumors of rice (Oryza sativa L.) (1996)
    Springer
    Biology and fertility of soils 21 (1996), S. 293-302 
    Details
    ISSN: 1432-0789
    Keywords: Key words Ammonium excretion ; Azorhizobium caulinodans ; Auxine ; 2 ; 4-Dichlor-phenoxy-acetic acid ; Nitrogen fixation ; Paranodulation ; Rice ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Rice seedlings developed nodule-like tumors (para-nodules) along primary and secondary roots when treated with the auxin 2,4-dichlor-phenoxy-acetic acid (2,4-D). Histologically, these tumors appeared as cancerous out-grown lateral-root primordes and were thus comparable with stem nodules of the legume Sesbania rostrata. Azorhizobium caulinodans (a diazotroph known as a specific endophyte of Sesbania rostrata) was introduced and became established inside rice para-nodules and in root tissues around tumor bases. The infection with A. caulinodans followed a typical “crack-entry” invasion at places where para-nodule tumors had emerged through the root cortex and epidermis. The bacteria settled with high cell densities in intercellular spaces of the induced tumors and betwen root cortical cells. Infection of plant cells took place both in the epidermis and in cortical tissue. Intracellularly established A. caulinodans was found inside the cytoplasm, surrounded by membrane-like structures. N2 fixation by tumor-inhabiting Azorhizobium sp. was increased at low O2 tensions (1.5–3 kPa) compared with an untreated control. Only a little activity remained at O2 tensions of 5 kPa and above. The present results confirm that root-tumor induction offers a suitable method of establishing diazotrophs endophytically in the roots of gramineous crops.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00334906
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 54
    Electronic Resource
    Electronic Resource
    Tree fallows: A comparison between five tropical tree species (1996)
    Springer
    Biology and fertility of soils 23 (1996), S. 50-56 
    Details
    ISSN: 1432-0789
    Keywords: Agroforestry ; 15N ; Nitrogen fixation ; Phenolics ; 13C ; Tree fallows
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The natural abundance of 15N and 13C, conventional soil analyses, and biomass production by maize were used to study the influence of five tropical tree species on soils and their fertility. The experiment was conducted in Morogoro, Tanzania, to compare Cassia (Senna) siamea, Eucalyptus camaldulensis, E. tereticornis (all non-N2-fixing), Leucaena leucocephala, Prosopis chilensis (both N2-fixing), and a grass fallow. Maize biomass production, which was correlated with N uptake (P=0.001), was higher on soils from plots with 5-year-old Leucaena and Prosopis spp. compared to the grass fallow, while other tree species had less favourable effects on maize growth. The per cent N was higher in soil and δ15N of soil total N was lower under Prosopis sp. compared to soil under other tree species, which suggests an input from N2 fixation by Prosopis sp. A transfer of fixed N to maize or to understorey grass species was, however, not indicated by the 15N natural abundance. Prosopis sp. contributed more C to the soil than the other four tree species; the difference in δ13C between soils from Prosopis sp. plots and from grass fallow plots showed that the tree contributed 11% to the total C of the soil over a period of 8 years. The leaves of the N2-fixing species had a low ratio of lignin+phenols to N, and maize growth was negatively correlated with this parameter. The Eucalyptus spp. had leaves with a high lignin+phenols to N ratio, contributed very little C to the soil, and lowered the soil pH.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00335818
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 55
    Electronic Resource
    Electronic Resource
    Occurrence of the endophytic diazotrophs Herbaspirillum spp. in roots, stems, and leaves, predominantly of Gramineae (1996)
    Springer
    Biology and fertility of soils 21 (1996), S. 197-200 
    Details
    ISSN: 1432-0789
    Keywords: Key words Herbaspirillum ; Endophytes of Gramineae ; Diazotrophs ; Survival in soil ; Nitrogen fixation ; Sugarcane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Since the first description of Herbaspirillum seropedicae in 1986, few data have been published on this diazotroph, possibly due to difficulties in isolating it from soil. In the present study we found that this bacterium seems to be an obligate endophyte which has been isolated from roots, stems, and leaves of a large number of samples of more than 10 different species of the Gramineae family, but only exceptionally from other plants. H. rubrisubalbicans, previously misnamed as “Pseudomonas” rubrisubalbicans, and known as a mild pathogen of sugarcane causing mottled stripe disease, confirms the endophytic habitat of this genus. This species occurs in roots, stems, and leaves of sugarcane and seems to be restricted to this crop. Inoculation of strains from both species into soil in high numbers resulted in a rapid decline in their numbers. In only 30 days the population of Herbaspirillum spp. in soil decreased below detection limits (〈100 cells g–1). When sorghum was planted in this soil, the bacteria reappeared and multiplied within the plant tissues.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00335935
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 56
    Electronic Resource
    Electronic Resource
    Endophytic establishment of Azorhizobium caulinodans through auxin-induced root tumors of rice (Oryza sativa L.) (1996)
    Springer
    Biology and fertility of soils 21 (1996), S. 293-302 
    Details
    ISSN: 1432-0789
    Keywords: Ammonium excretion ; Azorhizobium caulinodans ; Auxine 2.4-Dichlor-phenoxy-acetic acid ; Nitrogen fixation ; Paranodulation ; Rice ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Rice seedlings developed nodule-like tumors (para-nodules) along primary and secondary roots when treated with the auxin 2,4-dichlor-phenoxy-acetic acid (2,4-D). Histologically, these tumors appeared as cancerous out-grown lateral-root primordes and were thus comparable with stem nodules of the legume Sesbania rostrata. Azorhizobium caulinodans (a diazotroph known as a specific endophyte of Sesbania rostrata) was introduced and became established inside rice para-nodules and in root tissues around tumor bases. The infection with A. caulinodans followed a typical “crack-entry” invasion at places where paranodule tumors had emerged through the root cortex and epidermis. The bacteria settled with high cell densities in intercellular spaces of the induced tumors and between root cortical cells. Infection of plant cells took place both in the epidermis and in cortical tissue. Intracellularly established A. caulinodans was found inside the cytoplasm, surrounded by membrane-like structures. N2 fixation by tumor-inhabiting Azorhizobium sp. was increased at low O2 tensions (1.5–3 kPa) compared with an untreated control. Only a little activity remained at O2 tensions of 5 kPa and above. The present results confirm that root-tumor induction offers a suitable method of establishing diazotrophs endophytically in the roots of gramineous crops.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00334906
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 57
    Electronic Resource
    Electronic Resource
    Tree fallows: A comparison between five tropical tree species (1996)
    Springer
    Biology and fertility of soils 23 (1996), S. 50-56 
    Details
    ISSN: 1432-0789
    Keywords: Key words Agroforestry ; 15N ; Nitrogen fixation ; Phenolics ; 13C ; Tree fallows
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The natural abundance of 15N and 13C, conventional soil analyses, and biomass production by maize were used to study the influence of five tropical tree species on soils and their fertility. The experiment was conducted in Morogoro, Tanzania, to compare Cassia (Senna) siamea, Eucalyptus camaldulensis, E. tereticornis (all non-N2-fixing), Leucaena leucocephala, Prosopis chilensis (both N2-fixing), and a grass fallow. Maize biomass production, which was correlated with N uptake (P=0.001), was higher on soils from plots with 5-year-old Leucaena and Prosopis spp. compared to the grass fallow, while other tree species had less favourable effects on maize growth. The per cent N was higher in soil and δ15N of soil total N was lower under Prosopis sp. compared to soil under other tree species, which suggests an input from N2 fixation by Prosopis sp. A transfer of fixed N to maize or to understorey grass species was, however, not indicated by the 15N natural abundance. Prosopis sp. contributed more C to the soil than the other four tree species; the difference in δ13C between soils from Prosopis sp. plots and from grass fallow plots showed that the tree contributed 11% to the total C of the soil over a period of 8 years. The leaves of the N2-fixing species had a low ratio of lignin+phenols to N, and maize growth was negatively correlated with this parameter. The Eucalyptus spp. had leaves with a high lignin+phenols to N ratio, contributed very little C to the soil, and lowered the soil pH.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00335818
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 58
    Electronic Resource
    Electronic Resource
    Agricultural nitrogen model: A tool for regional environmental management (1983)
    Springer
    Environmental management 7 (1983), S. 177-187 
    Details
    ISSN: 1432-1009
    Keywords: Nitrogen ; Model ; Agriculture ; Mass balance ; Ground-water ; Denitrification ; Immobilization ; Dry deposition ; Nitrogen fixation ; Nitrate ; Florida
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract A detailed nitrogen budget was devised for agricultural activities in the Florida peninsula, based on routine data published by state agricultural agencies. The model demonstrates that important unmonitored fluxes of nitrogen can often be calculated by mass balance on individual model compartments, and that the reasonability of poorly quantified fluxes can be assessed. The results of such models can be very useful in designing and assessing the results of field experiments and in prioritizing environmental monitoring programs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01867279
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 59
    Electronic Resource
    Electronic Resource
    Relative levels of guanosine 5′-diphosphate 3′-diphosphate (ppGpp) in some N2 fixing bacteria during derepression and repression of nitrogenase (1981)
    Springer
    Archives of microbiology 128 (1981), S. 341-342 
    Details
    ISSN: 1432-072X
    Keywords: Nitrogen fixation ; Regulation ; Guanosine 5′-diphosphate 3′-diphosphate (ppGpp)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Addition of ammonium to N2 fixing cultures of Azotobacter vinelandii, Klebsiella pneumoniae and Clostridium pasteurianum rapidly reduced the intracellular levels of guanosine 5′-diphosphate 3′-diphosphate (ppGpp) by 70–90%. This change might reflect a regulatory role of ppGpp in nitrogen metabolism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00422542
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 60
    Electronic Resource
    Electronic Resource
    Hydrogen uptake deficient mutants of Rhodopseudomonas capsulata (1983)
    Springer
    Archives of microbiology 136 (1983), S. 20-25 
    Details
    ISSN: 1432-072X
    Keywords: Hydrogen production ; Nitrogen fixation ; Hydrogen recycling ; Hydrogenase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Mutants of Rhodopseudomonas capsulata lacking uptake hydrogenase activity have been isolated among those unable to grow photoautotrophically. Studies with these mutants showed increases in nitrogenase mediated H2 production from all substrates tested. In addition, photosynthetic synthetic growth on N2 with malate as carbon source was not affeced by the block in H2 uptake even under low light. Under these growth conditions hydrogen was observed to accumulate in mutant but not in wild-type cultures. This finding suggested that H2 was evolved by nitrogenase during N2 fixation by this photosynthetic bacterium and was efficiently recycled in the wild type.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00415604
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 61
    Electronic Resource
    Electronic Resource
    Effect of oxygen concentration on dark nitrogen fixation and respiration in cyanobacteria (1983)
    Springer
    Archives of microbiology 135 (1983), S. 287-292 
    Details
    ISSN: 1432-072X
    Keywords: Cyanobacteria ; Respiration ; Nitrogen fixation ; Heterocysts ; K m for O2 ; Anabaena variabilis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Simultaneous measurements of acetylene reduction by Anabaena variabilis and the concentration of dissolved oxygen in the suspension were made using a specially designed vessel which allowed measurements under steady-state conditions. The rate of acetylene reduction in the dark increased with increasing oxygen concentrations until a maximum value was reached at 300 μM O2 (corresponding to 30% O2 in the gas phase at 35°C). This presumably results from a requirement for energy provided by respiration. Measurements of the dependence of respiration rate on dissolved oxygen concentration were made under comparable conditions using an open system to allow conditions close to steady-state to be obtained. The respiration rate of diazotrophically grown Anabaena variabilis had a dependence on oxygen concentration corresponding to the sum of two activities. These had K m values of 1.0 μM and 69 μM and values of V max of similar magnitude. Only the high affinity activity was observed in nitrate-grown cyanobacteria lacking heterocysts, and this presumably represent activity in the vegetative cells. The oxygen concentration dependence of the low affinity activity resembled that for the stimulation of acetylene reduction. We interpret this as the result of oxygen uptake by the heterocysts. The results are consistent with the idea that in intact filaments of cyanobacteria O2 enters heterocysts much more slowly than it enters the vegetative cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00413483
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 62
    Electronic Resource
    Electronic Resource
    The relationship between the state of adenylylation of glutamine synthetase I and the export of ammonium in free-living, N2-fixing Rhizobium (1984)
    Springer
    Archives of microbiology 138 (1984), S. 26-30 
    Details
    ISSN: 1432-072X
    Keywords: Ammonium export ; Ammonium assimilation ; Glutamine synthetase ; Nitrogen fixation ; Rhizobium sp. 32H1
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The relationship between ammonium assimilation and ammonium export has been studied in free-living, N2-fixing Rhizobium sp. 32H1. After 55 to 67 h of microaerobic growth under a gas phase of 0.2% O2 – 1.0% CO2 – 98.8% Ar high levels of nitrogenase were observed concomitant with a slightly adenylylated glutamine synthetase (GSI) and some glutamine synthetase (GSII) activity. However, after growth of 89 h, or longer, GSI became adenylylated and the level of GSII had decreased. When the gas phase was shifted to 0.2% O2 – 1.0% CO2 – 98.8% N2, a lag was observed before ammonium export could be detected in the 55 to 67 h cultures. No lag in ammonium export was observed in the cultures previously grown for 89 h. The onset of ammonium export in the 55 to 67 h cultures was found to correlate with the adenylylation state of GSI. There appeared to be no correlation between the level of GSII and the export of ammonium. Neither an increase in the adenylylation level of GSI nor ammonium export was observed when the 55 to 67 h cultures were maintained under the Ar gas mixture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00425402
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 63
    Electronic Resource
    Electronic Resource
    Evidence for adenylylation/deadenylylation control of the glutamine synthetases of Rhodospirillum tenue and Rhodocyclus purpureus (1985)
    Springer
    Archives of microbiology 142 (1985), S. 103-108 
    Details
    ISSN: 1432-072X
    Keywords: Phototrophic bacteria ; Rhodospirillaceae ; Glutamine synthetase ; Nitrogen metabolism ; Nitrogen fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The phylogenetically related phototrophic bacteria Rhodospirillum tenue and Rhodocyclus purpureus modulate activity of their glutamine synthetases by adenylylation/deadenylylation. Evidence for covalent modification includes the inhibitory effect of Mg2+ on the activity of glutamine synthetase extracted from cells of either species grown on excess ammonia, and the lack of Mg2+ inhibition of activity of the enzyme isolated from N2-(R. tenue) or glutamine (R. purpureus)-grown cells. In addition, snake venom phosphodiesterase treatment of glutamine synthetase from either species grown on excess ammonia relieved Mg2+ inhibition of the enzyme (as measured via the γ-glutamyl transferase assay), and changed the cation specificity from Mn2+ to Mg2+ (in the biosynthetic assay).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00447051
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 64
    Electronic Resource
    Electronic Resource
    Assimilation of exogenous and dinitrogen-derived13NH 4 + byAnabaena azollae separated fromAzolla caroliniana Willd (1985)
    Springer
    Archives of microbiology 142 (1985), S. 229-233 
    Details
    ISSN: 1432-072X
    Keywords: Ammonium assimilation ; Excretion ; Anabaena azollae ; Azolla caroliniana ; Cyanobacteria ; Glutamine ; Glutamate formation ; Nitrogen fixation ; Symbiosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Anabaena azollae was isolated fromAzolla caroliniana by the “gentle roller” method and differential centrifugation. Incubation of suchAnabaena preparations for 10 min with [13N]N2 resulted in the formation of four radioactive compounds; ammonium, glutamine, glutamate and alanine. Ammonium accounted for 66% of the total radioactivity recovered and 58% of the ammonium was in an extracellular fraction. Since essentially no extracellular13N-labeled organic compounds were found, it appears that ammonium is the compound most probably made available toAzolla during dinitrogen-dependent growth of the association. The kinetics of incorporation of exogenous13NH 4 + into glutamine and glutamate were characteristic of a precursor (glutamine)-product (glutamate) relationship and consistent with assimilation by the glutamine synthetase-glutamate synthase pathway. The results of experiments using the glutamine synthetase inhibitor, methionine sulfoximine, the glutamate synthase inhibitor, diazo-oxonorleucine, and increasing the ammonium concentration to greater than 1 mM, provided evidence for assimilation primarily by the glutamine synthetase-glutamate synthase pathway with little or no contribution from biosynthetic glutamate dehydrogenase. While showing that N2 fixation and NH 4 + assimilation were not tightly coupled metabolic processes in symbioticAnabaena, these results reflect a composite picture and do not indicate the extent to which ammonium assimilatory enzymes might be regulated in filaments associated with specific stages in theAzolla-Anabaena developmental profile.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00693395
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 65
    Electronic Resource
    Electronic Resource
    Oxygen protection of nitrogenase in the aerobically nitrogen fixing, non-heterocystous cyanobacterium Oscillatoria sp. (1985)
    Springer
    Archives of microbiology 143 (1985), S. 72-76 
    Details
    ISSN: 1432-072X
    Keywords: Oscillatoria ; Cyanobacteria ; Nitrogen fixation ; Oxygen protection of N2-ase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Oscillatoria sp. strain 23 is a filamentous, non-heterocystous cyanobacterium that fixes nitrogen aerobically. Although, in this organism nitrogenase is inactivated by oxygen a high tolerance is observed. Up to a pO2 of 0.15 atm, oxygen does not have any measurable effects on acetylene reduction. Higher concentrations of oxygen inhibited the activity to a relatively high degree. Evidence for two mechanisms of oxygen protection of nitrogenase in this cyanobacterium was obtained. A high rate of synthesis of nitrogenase may allow the organism to maintain a certain amount of active enzyme under aerobic conditions. Secondly, a switch off/on mechanism may reversibly convert the active enzyme into a non-active form which is insensitive to oxygen inactivation after a sudden and short-term exposure to high oxygen concentrations. It is conceived that these mechanisms in addition to a temporal separation of nitrogen fixation from oxygenic photosynthesis sufficiently explain the regulation process of aerobic nitrogen fixation in this organism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00414771
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 66
    Electronic Resource
    Electronic Resource
    Nitrogenase activity in the non-heterocystous cyanobacterium Oscillatoria sp. grown under alternating light-dark cycles (1985)
    Springer
    Archives of microbiology 143 (1985), S. 67-71 
    Details
    ISSN: 1432-072X
    Keywords: Oscillatoria ; Cyanobacteria ; Nitrogen fixation ; Light-dark cycles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The non-heterocystous cyanobacterium Oscillatoria sp. strain 23 fixes nitrogen under aerobic conditions. If nitrate-grown cultures were transferred to a medium free of combined nitrogen, nitrogenase was induced within about 1 day. The acetylene reduction showed a diurnal variation under conditions of continuous light. Maximum rates of acetylene reduction steadily increased during 8 successive days. When grown under alternating light-dark cycles, Oscillatoria sp. fixes nitrogen preferably in the dark period. For dark periods longer than 8 h, nitrogenase activity is only present during the dark period. For dark periods of 8 h and less, however, nitrogenase activity appears before the beginning of the dark period. This is most pronounced in cultures grown in a 20 h light – 4 h dark cycle. In that case, nitrogenase activity appears 3–4 h before the beginning of the dark period. According to the light-dark regime applied, nitrogenase activity was observed during 8–11 h. Oscillatoria sp. grown under 16 h light and 8 h dark cycle, also induced nitrogenase at the usual point of time, when suddenly transferred to conditions of continuous light. The activity appeared exactly at the point of time where the dark period used to begin. No nitrogenase activity was observed when chloramphenicol was added to the cultures 3 h before the onset of the dark period. This observation indicated that for each cycle, de novo nitrogenase synthesis is necessary.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00414770
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 67
    Electronic Resource
    Electronic Resource
    Indigenous plasmids and cultural characteristics of rhizobia nodulating chickpeas (Cicer arietinum L.) (1986)
    Springer
    Archives of microbiology 146 (1986), S. 239-244 
    Details
    ISSN: 1432-072X
    Keywords: Cicer arietinum ; nif Genes ; Plasmids ; Rhizobia ; DNA/DNA hybridization ; Nitrogen fixation ; Chickpeas
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We examined 27 strains of chickpea rhizobia from different geographic origins for indigenous plasmids, location and organization of nitrogen fixation (nif) genes, and cultural properties currently used to separate fast- and slow-growing groups of rhizobia. By using an in-well lysis and electrophoresis procedure one to three plasmids of molecular weights ranging from 35 to higher than 380 Mdal were demonstrated in each of 19 strains, whereas no plasmids were detected in the eight remaining strains. Nitrogenase structural genes homologous to Rhizobium meliloti nifHD, were not detected in plasmids of 26 out of the 27 strains tested. Hybridization of EcoRI digested total DNA from these 26 strains to the nif probe from R. meliloti indicated that the organization of nifHD genes was highly conserved in chickpea rhizobia. The only exception was strain IC-72 M which harboured a plasmid of 140 Mdal with homology to the R. meliloti nif DNA and exhibited also a unique organization of nifHD genes. The chickpea rhizobia strains showed a wide variation of growth rates (generation times ranged from 4.0 to 14.5 h) in yeast extract-mannitol medium but appear to be relatively homogeneous in terms of acid production in this medium and acid reaction in litmus milk. Although strains with fast and slow growth rates were identified, DNA/DNA hybridization experiments using a nifHD-specific probe, and the cultural properties examined so far do not support the separation of chickpea rhizobia into two distinct groups of the classical fast- and slow-growing types of rhizobia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00403223
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 68
    Electronic Resource
    Electronic Resource
    Melanin production encoded by a cryptic plasmid in a Rhizobium leguminosarum strain (1988)
    Springer
    Archives of microbiology 150 (1988), S. 326-332 
    Details
    ISSN: 1432-072X
    Keywords: Rhizobium leguminosarum ; Plasmids ; Melanin ; Nodulation ; Nitrogen fixation ; Plasmid curing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Rhizobium leguminosarum strain VF39, isolated from nodules of field-grown faba beans in the Federal Republic of Germany, was shown to contain six plasmids ranging in molecular weight from 90 to 400 Md. Hybridisation to nif gene probes, plasmid curing, and mobilisation to other strains of Rhizobium and to Agrobacterium showed that the third largest plasmid, pRleVF39d (220 Md), carried genes for nodulation and nitrogen fixation. This plasmid was incompatible with pRL10JI, the Sym plasmid of R. leguminosarum strain JB300. Of the other plasmids, the two smallest (pRleVF39a and pRleVF39b, 90 and 160 Md respectively) were shown to be self-transmissible at a low frequency. Although melanin production is as yet unreported in strains of R. leguminosarum biovar viceae, strain VF39 produced a dark pigment, which, since it was not produced on minimal media and its production was greatly enhanced by the presence of tyrosine in the media, is probably melanin-like. Derivatives of VF39 cured of pRleVF39a no longer produced this pigment, but regained the ability to produce it when this plasmid was transferred into them. Strains of Agrobacterium tumefaciens, R. meliloti, and some strains of R. leguminosarum carrying pRleVF39a did not produce this pigment, indicating perhaps that some genes elsewhere on the VF39 genome are also involved in pigment production. Plasmid pRleVF39a appeared to be incompatible with the cryptic Rhizobium plasmids pRle336b and pRL8JI (both ca. 100 Md), but was compatible with the R. leguminosarum biovar phaseoli Sym plasmids pRP1JI, pRP2JI and pRph51a, all of which also code for melanin production. The absence of pRleVF39a in cured derivatives of VF39 had no effect on the symbiotic performance or competitive ability of this strain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00408302
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 69
    Electronic Resource
    Electronic Resource
    New types of acetate-oxidizing, sulfate-reducing Desulfobacter species, D. hydrogenophilus sp. nov., D. latus sp. nov., and D. curvatus sp. nov. (1987)
    Springer
    Archives of microbiology 148 (1987), S. 286-291 
    Details
    ISSN: 1432-072X
    Keywords: Sulfate-reducing bacteria ; Desulfobacter species ; Acetate ; Hydrogen ; Autotrophic growth ; Nitrogen fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Sulfate-reducing bacteria with oval to rod-shaped cells (strains AcRS1, AcRS2) and vibrio-shaped cells (strains AcRM3, AcRM4, AcRM5) differing by size were isolated from anaerobic marine sediment with acetate as the only electron donor. A vibrio-shaped type (strain AcKo) was also isolated from freshwater sediment. Two strains (AcRS1, AcRM3) used ethanol and pyruvate in addition to acetate, and one strain (AcRS1) grew autotrophically with H2, sulfate and CO2. Higher fatty acids or lactate were never utilized. All isolates were able to grow in ammonia-free medium in the presence of N2. Nitrogenase activity under such conditions was demonstrated by the acetylene reduction test. The facultatively lithoautotrophic strain (AcRS1), a strain (AcRS2) with unusually large cells (2×5 μm), and a vibrio-shaped strain (AcRM3) are described as new Desulfobacter species, D. hydrogenophilus, D. latus, and D. curvatus, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00456706
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 70
    Electronic Resource
    Electronic Resource
    The calcium requirement for functional vesicle development and nitrogen fixation by Frankia strains EAN1pec and CpI1 (1987)
    Springer
    Archives of microbiology 149 (1987), S. 24-29 
    Details
    ISSN: 1432-072X
    Keywords: Frankia ; Nitrogen fixation ; Calcium ; Vesicle development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A calcium requirement was shown for both vesicle development and nitrogenase activity by Frankia strains EAN1pec and CpI1. Washing cells with EGTA or EDTA inhibited both vesicle development and nitrogenase activity. The inhibition of both was reversed by the addition of calcium. A variety of agents known to affect calcium-dependent biological processes, such as a Ca-ATPase inhibitor, Ca-channel blockers, Ca-ionophores, calmodulin antagonists and the local anaesthetics, tetracaine and dibucaine, inhibited nitrogenase activity. Respiratory studies showed that a CN-insensitive respiration process occurred only under nitrogen derepressing conditions. Respiration by NH4Cl-grown cells was completely inhibited by KCN while N2-grown cells were inhibited by only 70%. Removal of calcium ions by EGTA or by the addition of dibucaine or tetracaine blocked the CN-insensitive respiration. This CN-insensitive respiration may be involved in protecting nitrogenase inside the vesicles from oxygen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00423131
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 71
    Electronic Resource
    Electronic Resource
    The occurrence of coryneform bacteria in the leaf cavity of Azolla (1980)
    Springer
    Archives of microbiology 127 (1980), S. 163-165 
    Details
    ISSN: 1432-072X
    Keywords: Nitrogen fixation ; Arthrobacter ; Corynebacterium ; Anabaena azollae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Coryneform bacteria were found associated with the nitrogen fixing blue-green alga, Anabaena azollae in the leaf cavity of Azolla caroliniana. Plate counts indicated ca. 7,400±1,900 bacterial cells per mature leaf cavity or approximately 1 bacterial cell for every algal cell. No other type of bacterium was found in these cavities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00428020
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 72
    Electronic Resource
    Electronic Resource
    Antigenic differences between Anabaena azollae fresh from the Azolla fern leaf cavity and free-living cyanobacteria (1980)
    Springer
    Archives of microbiology 128 (1980), S. 126-129 
    Details
    ISSN: 1432-072X
    Keywords: Fluorescent antibody staining ; Nitrogen fixation ; Symbiosis ; Anabaena azollae ; Azolla caroliniana
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Fluorescent antibody staining indicated differences in surface antigenicity in Anabaena azollae cells fresh from the leaf cavities of the fern, Azolla caroliniana, and algae which were isolated and subcultured from this fern. Such results suggest that either changes in antigenicity occur in this phycobiont during culturing or that isolation selects for an antigenically different mutant strain capable of in vitro growth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00422316
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 73
    Electronic Resource
    Electronic Resource
    The uptake and hydrolysis of disaccharides by fast-and slow-growing species of Rhizobium (1981)
    Springer
    Archives of microbiology 129 (1981), S. 238-239 
    Details
    ISSN: 1432-072X
    Keywords: Rhizobium ; Disaccharide ; Bacteroid ; Transport ; Nitrogen fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Slow growing strains of rhizobia appear to lack both uptake systems and catabolic enzymes for disaccharides. In the fast-growing strains of rhizobia there are uptake mechanisms and catabolic enzymes for disaccharide metabolism. In Rhizobium leguminosarum WU 163 and WU235 and R. trifolii WU290, sucrose and maltose uptake appears to be constitutive whereas in R. meliloti WU60 and in cowpea Rhizobium NGR234 uptake of these disaccharides is inducible. There is evidence that there are at least two distinct disaccharide uptake systems in fast-growing rhizobia, one transporting sucrose, maltose and trehalose and the other, lactose. Disaccharide uptake is via an active process since uptake is inhibited by azide, dinitrophenol and carbonyl cyanide m-chlorophenylhydrazone but not by arsenate. Bacteroids of R. leguminosarum WU235 and R. lupini WU8 are unable to accumulate disaccharides.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00425257
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 74
    Electronic Resource
    Electronic Resource
    Regulation of nitrogenase messenger RNA synthesis and stability in Klebsiella pneumoniae (1981)
    Springer
    Archives of microbiology 130 (1981), S. 38-43 
    Details
    ISSN: 1432-072X
    Keywords: Nitrogen fixation ; Gene expression ; Regulation ; Messenger RNA ; Transcription ; Klebsiella pneumoniae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Nitrogenase messenger RNA synthesis in Klebsiella pneumoniae was determined by labelling cells with (3H)uracil and isolating total RnA, which was then hybridized to filterbound recombinant plasmid pSA30 DNA carrying the nitrogenase structural genes nifH, D, and K. Derepression of nitrogenase mRNA starts 1.5 h before the onset of nitrogenase activity (as measured by acetylene reduction). Exposure of nif-derepressed cultures to either NH 4 + , air, or high temperatures (39° C) results in a rapid decrease of the synthesis rates both of nitrogenase mRNA and nitrogenase polypeptides. Nitrogenase mRNA is remarkably stable. After blocking transcription with rifampicin, hybridizable and actively translatable nitrogenase mRNA survives with an average half-life of 18 min. Half-lives are considerably shorter when rifampicin-inhibited cultures are simultaneously shifted to conditions which are non-permissive for nitrogenase synthesis, pointing to some posttranscriptional influence on nitrogenase mRNA stability. In all experiments performed there was no evidence for uncoupling of nitrogenase mRNA synthesis from nitrogenase mRNA translation, indicating that nitrogenase synthesis is regulated solely by transcriptional control.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00527069
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 75
    Electronic Resource
    Electronic Resource
    Regulation of nitrogenase activity by covalent modification in Chromatium vinosum (1985)
    Springer
    Archives of microbiology 141 (1985), S. 40-43 
    Details
    ISSN: 1432-072X
    Keywords: Nitrogenase ; Nitrogen fixation ; Regulation ; Photosynthetic bacteria ; Chromatium ; Ammonia switch off
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Nitrogenase in Chromatium vinosum was rapidly, but reversibly inhibited by NH 4 + . Activity of the Fe protin component of nitrogenase required both Mn2+ and activating enzyme. Activating enzyme from Rhodospirillum rubrum could replace Chromatium chromatophores in activating the Chromatium Fe protein, and conversely, a protein fraction prepared from Chromatium chromatophores was effective in activating R. rubrum Fe protein. Inactive Chromatium Fe protein contained a peptide covalently modified by a phosphate-containing molecule, which migrated the same in SDS-polyacrylamide gels as the modified subunit of R. rubrum Fe protein. In sum, these observations suggest that Chromatium nitrogenase activity is regulated by a covalent modification of the Fe protein in a manner similar to that of R. rubrum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00446737
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 76
    Electronic Resource
    Electronic Resource
    Organisation of nodulation and nitrogen fixation genes on a Rhizobium trifolii symbiotic plasmid (1984)
    Springer
    Archives of microbiology 139 (1984), S. 151-157 
    Details
    ISSN: 1432-072X
    Keywords: Rhizobium trifolii ; Symbiosis ; Nodulation ; Nitrogen fixation ; Symbiotic genes ; Reiterated sequences ; Plasmid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A Rhizobium trifolii symbiotic plasmid specific gene library was constructed and the physical organisation of regions homologous to nifHDK, nifA and nod genes was determined. These symbiotic gene regions were localised to u 25 kb region on the sym-plasmid, pPN1. In addition four copies of a reiterated sequence were identified on this plasmid, with one copy adjacent to nifH. No rearrangement of these reiterated sequences was observed between R. trifolii bacterial and bacteroid DNA. Analysis of a deletion derivative of pPN1 showed that these sequences were spread over a 110 kb region to the left of nifA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00401991
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 77
    Electronic Resource
    Electronic Resource
    Interactions between cyanobacterium and fungus during 15N2-incorporation and metabolism in the lichen Peltigera canina (1983)
    Springer
    Archives of microbiology 134 (1983), S. 136-142 
    Details
    ISSN: 1432-072X
    Keywords: Ammonia assimilation ; Lichen symbioses ; Nitrogen fixation ; 15N kinetics ; Peltigera canina
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract On following N2-incorporation and subsequent metabolism in the lichen Peltigera canina using 15N as tracer, it was found, over a 30 min period, that greatest initial labelling was into NH 4 + followed by glutamate and the amide-N of glutamine. Labelling of the amino-N of glutamine, aspartate and alanine increased slowly. Pulse-chase experiments using 15N confirmed this pattern. On inhibiting the GS-GOGAT pathway using l-methionine-dl-sulphoximine and azaserine, 15N enrichment of glutamate, alanine and aspartate continued although labelling of glutamine was undetectable. From this and enzymic data, NH 4 + assimilation in the P. canina thallus appears to proceed via GS-GOGAT in the cyanobacterium and via GDH in the fungus; aminotransferases were present in both partners. The cyanobacterium assimilated 44% of the 15N2 fixed; the remainder was liberated almost exclusively as NH 4 + and then assimilated by fungal GDH.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00407946
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 78
    Electronic Resource
    Electronic Resource
    RNA polymerase from Rhizobium japonicum (1983)
    Springer
    Archives of microbiology 135 (1983), S. 103-109 
    Details
    ISSN: 1432-072X
    Keywords: RNA polymerase ; Transcription ; Nitrogen fixation ; Symbiosis ; Rhizobium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract DNA-dependend RNA polymerase (EC 2.7.7.6) from Rhizobium japonicum was purified. The subunit structure was found to be ββ′α2σ, with the following apparent molecular weights determined by electrophoresis: M r (β and β') 150,000 each, M r (σ) 96,000, M r (α) 40,000, M r (holoenzyme) 490,000, M r (core enzyme) 380,000. The recovery of σ was 28%. RNA polymerase from aerobically grown R. japonicum cells and from nitrogen-fixing cells have the same electrophoretic properties suggesting that no chemical modification of the enzyme occurs when cells undergo this metabolic differentiation. The enzyme is Mg2+-dependent, rifampicin-sensitive, and has optimal activity at alkaline pH (8–10) and at 35–40° C. It binds strongly to bacteriophage T7 promoters, weakly to antibiotic resistance genes, and not at all to cloned R. japonicum nif DNA. Preliminary in vitro transcription experiments, including nif DNA as template, revealed that additional factors may be required for selective transcription from promoters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00408017
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 79
    Electronic Resource
    Electronic Resource
    Nitrogen metabolism in Xanthobacter H4-14 (1983)
    Springer
    Archives of microbiology 136 (1983), S. 219-221 
    Details
    ISSN: 1432-072X
    Keywords: Xanthobacter ; Nitrogen fixation ; Oxygen sensitivity ; Nitrogen metabolism ; Glutamine synthetase ; Glutamate synthase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract N2-fixation was investigated in the chemoautotrophic hydrogen bacterium Xanthobacter H4-14. N2-fixing batch cultures of this organism could only be grown at pO2 values of around 0.02 bar, and in continuous culture dissolved oxygen tensions above 16 μM were found to inhibit N2-fixation. Xanthobacter H4-14 utilized a variety of amino acids, nitrate and ammonia as nitrogen sources. Cell-free extracts from steady-state continuous cultures of ammonia grown, nitrate grown and N2-fixing Xanthobacter were assayed for the presence of ammonia assimilation enzymes. No alanine dehydrogenase or glutamate dehydrogenase activity was detected. Ammonia was assimilated exclusively via the glutamine synthetase/glutamate synthase pathway, irrespective of the extracellular concentration of ammonia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00409848
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 80
    Electronic Resource
    Electronic Resource
    Electron donation to nitrogenase in heterocysts of cyanobacteria (1985)
    Springer
    Archives of microbiology 143 (1985), S. 185-191 
    Details
    ISSN: 1432-072X
    Keywords: Heterocyst ; Pyruvate: ferredoxin oxidoreductase ; Nitrogen fixation ; Electron transport to nitrogenase ; Ferredoxin ; Cyanobacteria ; Anabaena cylindrica ; Anabaena variabilis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Various electron donors were found to stimulate C2H2 reduction (N2 fixation) by isolated heterocysts from Anabaena variabilis and Anabaena cylindrica. Intermediates of glycolysis and the tricarboxylic acid cycle as well as unphosphorylated sugars like glucose, fructose and erythrose were among these electron donors. The transfer of electrons from donors like H2, NADH, glyoxylate and glycollate was strictly light-dependent, whereas others like NADPH or pyruvate plus coenzyme A supported C2H2 reduction also in the dark. In all cases, the overall activity was enhanced by light. The stimulation by light was more distinct with heterocysts from A. variabilis than with heterocysts from A. cylindrica. The present communication establishes that pyruvate supports C2H2 reduction by heterocysts from either A. variabilis or A. cylindrica with rates comparable to those with other electron donors. Pyruvate could, however, support C2H2 reduction only in the presence of coenzyme A, and the concentrations of both coenzyme A and pyruvate were crucial. A pyruvate-dependent reduction of ferredoxin by extracts from heterocysts was recorded spectrophotometrically. Glyoxylate, which is an inhibitor of thiamine pyrophosphate-dependent decarboxylations, inhibited pyruvate-dependent C2H2 reduction. This result supports the conclusion that pyruvate is metabolised by pyruvate: ferredoxin oxidoreductase in heterocysts. High concentrations of pyruvate and other electron donors inhibited C2H2 reduction which suggests that nitrogenase activity in heterocysts may be controlled by the availability of electron donors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00411045
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 81
    Electronic Resource
    Electronic Resource
    Aspects of nitrogen fixation in Chlorobium (1986)
    Springer
    Archives of microbiology 143 (1986), S. 330-336 
    Details
    ISSN: 1432-072X
    Keywords: Phototrophic bacteria ; Green sulfur bacteria ; Chtorobium ; Nitrogen fixation ; Nitrogenase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Four strains of the green sulfur bacterium Chlorobium were studied in respect to nitrogen nutrition and nitrogen fixation. All strains grew on ammonia, N2, or glutamine as sole nitrogen sources; certain strains also grew on other amino acids. Acetylene-reducing activity was detectable in all strains grown on N2 or on amino acids (except for glutamine). In N2 grown Chlorobium thiosulfatophilum strain 8327 1 mM ammonia served to “switch-off” nitrogenase activity, but the effect of ammonia was much less dramatic in glutamate or limiting ammonia grown cells. The glutamine synthetase inhibitor methionine sulfoximine inhibited ammonia “switch-off” in all but one strain. Cell extracts of glutamate grown strain 8327 reduced acetylene and required Mg2+ and dithionite, but not Mn2+, for activity. Partially purified preparations of Rhodospirillum rubrum nitrogenase reductase (iron protein) activating enzyme slightly stimulated acetylene reduction in extracts of strain 8327, but no evidence for an indigenous Chlorobium activating enzyme was obtained. The results suggest that certain Chlorobium strains are fairly versatile in their nitrogen nutrition and that at least in vivo, nitrogenase activity in green bacteria is controlled by ammonia in a fashion similar to that described in nonsulfur purple bacteria and in Chromatium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00412798
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 82
    Electronic Resource
    Electronic Resource
    Symbiotically defective histidine auxotrophs of Bradyrhizobium japonicum (1986)
    Springer
    Archives of microbiology 144 (1986), S. 334-339 
    Details
    ISSN: 1432-072X
    Keywords: Transposon mutagenesis ; Soybean ; Nitrogen fixation ; Root nodules ; Auxotrophy ; Bradyrhizobium japonicum ; Glycine ; Rhizobium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Four histidine auxotrophs of Bradyrhizobium japonicum strain USDA 122 were isolated by random transposon Tn5 mutagenesis. These mutants arose from different, single transposition events as shown by the comparison of EcoRI and XhoI-generated Tn5 flanking sequences of genomic DNA. The mutants grew on minimal medium supplemented with l-histidine or l-histidinol but failed to grow with l-histidinol phosphate. While two of the muants were symbiotically defective and did not form nodules on Glycine max cvs. Lee and Peking and on Glycine soja, the other two mutants were symbiotically competent. Reversion to prototrophy occurred at a frequency of about 10-7 on growth medium without added antibiotics, but prototrophs could not be isolated from growth medium containing 200 μg/ml kanamycin and streptomycin. The prototrophic revertants formed nodules on all the soybean cultivars examined. When histidine was supplied to the plant growth medium, both nodulation deficient mutants formed effective symbioses. On histidine unamended plants, nodules were observed infrequently. Three classes of bacterial colonies were isolated from such infrequent nodules: class 1 were kanamycin resistant-auxotrophs; class 2 were kanamycin sensitive-prototrophs; and class 3 were kanamycin-sensitive auxotrophs. Our results suggest that two Tn5 insertion mutations in B. japonicum leading to histidine auxotrophy, affect nodulation in some way. These mutations are in regions that show no homology to the Rhizobium meliloti common nodulation genes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00409881
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 83
    Electronic Resource
    Electronic Resource
    Nitrogen fixation in strains ofAzotobacter chroococcum bearing deletions of a cluster of genes coding for nitrogenase (1986)
    Springer
    Archives of microbiology 146 (1986), S. 74-79 
    Details
    ISSN: 1432-072X
    Keywords: Azotobacter chroococcum ; Nitrogen fixation ; Nitrogenase genes ; Nif gene reiteration ; Deletion mutagenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Strains of the obligately aerobic nitrogen fixing organismAzotobacter chroococcum were constructed which contained defined chromosomal deletions in which the nitrogenase structural genenifHDK cluster (nifH for the polypeptide of the Fe-protein component of nitrogenase andnifD andnifK for the alpha and beta subunits respectively of the MoFe-protein component of the enzyme) was replaced by a kanamycin resistance gene. N2 fixation was nevertheless observed in deletion strains though only in a molybdenum-deficient medium or in spontaneously arising tungstate-resistant derivatives. In comparison with the parent strain growing in molybdenum-sufficient medium, diazotrophic growth was slow and the nitrogenase activity in vivo was characterised by disproportionately low rates of C2H2-reduction compared to H2-evolution and relative insensitivity of H2-evolution to inhibition by C2H2. The findings show reiteration of functional structural genes for nitrogenase inA. chroococcum consistent with our previous observation of twonifH genes in this organism and detection in this work of a secondnifK-like sequence in the genomes of both parent and deletion strains whenA. chroococcum nifK DNA was used as a probe.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00690162
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 84
    Electronic Resource
    Electronic Resource
    Some properties of arctic rhizobia (1986)
    Springer
    Archives of microbiology 146 (1986), S. 12-18 
    Details
    ISSN: 1432-072X
    Keywords: Arctic rhizobia ; Arctic legumes ; Nitrogen fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Forty-eight strains of Rhizobium isolated from the root nodules of three species of legumes indigenous to the high tundra (Astragalus alpinus, Oxytropis maydelliana andOxytropis arctobia) are phenotypically heterogenous with respect to intrinsic antibiotic resistance, expression of nitrogenase activityex planta and plasmid content. All of the strains possess a 250–300 kb plasmid and are homologous to each other on the genomic DNA level but have little DNA homology with selected reference strains of well characterized species of rhizobia. The arctic rhizobia have an optimum growth temperature of 23°C and can grow slowly at 5°C. The DNA from four of the isolates, which were selected for detailed investigation, have sequences homologous tonif andnod genes fromRhizobium trifolii.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00690151
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 85
    Electronic Resource
    Electronic Resource
    Comparative physiology of nitrogenase activity and vesicle development for Frankia strains CpI1, ACN1 ag , EAN1pec and EUN1f (1987)
    Springer
    Archives of microbiology 147 (1987), S. 383-388 
    Details
    ISSN: 1432-072X
    Keywords: Frankia ; Nitrogen fixation ; Vesicle development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The relationship between nitrogen fixation and development of a specialized cell structure, called the vesicle, was studied using four Frankia isolates. Nitrogenase activity was repressed in all four strains during growth with ammonia. Strain CpI1 formed no vesicles during NH4 growth. Strains ACN1 ag , EAN1pec and EUN1f produced low numbers of vesicles in the presence of ammonia. Following transfer to nitrogen-free media, a parallel increase in nitrogenase activity and vesicle numbers occurred with all four isolates. Appearance of nitrogenase activity was more rapid in those strains that possessed some vesicles at the time of shift to N2 as a nitrogen source. The ratio of vesicle numbers to level of nitrogenase activity varied widely among the four strains and in response to different growth conditions and culture age of the individual strains. Optimum conditions of temperature, carbon and energy source, nitrogen source and availability of iron and molybdenum were different for each of the four strains. Those conditions that significantly reduced nitrogenase activity were always associated with decreased numbers of vesicles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00406137
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 86
    Electronic Resource
    Electronic Resource
    Occurrence of nitrogen fixation among Vibrio spp. (1988)
    Springer
    Archives of microbiology 150 (1988), S. 224-229 
    Details
    ISSN: 1432-072X
    Keywords: Vibrio ; V. diazotrophicus ; V. natriegens ; V. pelagius ; V. cincinnatiensis ; Nitrogenase ; Nitrogen fixation ; Oxygen sensitivity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Virtually all Vibrio spp. known and available in culture collections and several newly isolated Vibrio sp. were tested for their ability to fix molecular nitrogen, using the acetylene reduction technique, the fixation of the heavy isotope 15N, and by growth on media devoid of combined nitrogen. Among the 27 species tested, four, including V. diazotrophicus, proved to be nitrogenase-positive. The potential of nitrogen fixation was now also discovered in V. natriegens, V. pelagius and V. cincinnatiensis. Among the 9 newly isolated strains, 4 were nitrogenase-positive. These strains were classified as V. diazotrophicus on the basis of DNA homology studies. Nitrogenase was only induced during growth under anaerobic conditions. Dissolved oxygen as low as 1 μM inhibited nitrogenase completely. This inhibition at low oxygen concentration, however, was reversible. 50–100 μM dissolved oxygen inhibited nitrogenase irreversibly.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00407784
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 87
    Electronic Resource
    Electronic Resource
    Isolation and characterization of hydrogenase-negative mutants of Azorhizobium caulinodans ORS571 (1988)
    Springer
    Archives of microbiology 150 (1988), S. 595-599 
    Details
    ISSN: 1432-072X
    Keywords: Azorhizobium caulinodans ORS571 ; Hydrogenase ; Nitrogen fixation ; Chemostat cultures ; H2/N2 ratio ; ATP/2e value
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Hydrogenase-negative (Hup-) mutants of Azorhizobium caulinodans ORS571 were isolated by means of Tn5 mutagenesis. The colony test used for screening for Hup- strains was based on the absence of reduction of triphenyltetrazolium chloride with hydrogen. Suspensions from cultures of the mutant strains grown under derepressing conditions did not use hydrogen with methylene blue or oxygen as the hydrogen acceptor. The mutants were shown to carry single Tn5 insertions at different locations in the A. caulinodans genome. Molar growth yields (corrected for poly-β-hydroxybutyrate formation) in chemostat cultures of the mutants were similar to those of the wild type. Molar growth yields of the mutants were not increased by passing additional hydrogen through chemostat cultures, which is in agreement with the hydrogenase-negative phenotype of the mutants. H2/N2 ratios (mol H2 formed per mol N2 fixed) were calculated from the hydrogen content of the effluent gas and the N-content of the bacterial dry weight. Low H2/N2 ratios (between 1.2 and 1.9) were found in both energy-limited (oxygen or succinate) cultures and in cultures limited by the supply of an anabolic substrate (Mg2+). ATP/2e values (mol ATP used at the transport of 2e to nitrogen or H+) were calculated from the H2/N2 ratios and the molar growth yields of nitrogen-fixing and ammonia-assimilating cultures. ATP/2e values were between 7 and 11. It was concluded that the calculated ATP/2e values comprise not only 4 mol ATP used at the transport of 2e through nitrogenase but also energy equivalents needed for reversed electron flow from NADH to the low-potential hydrogen donor used by nitrogenase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00408256
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 88
    Electronic Resource
    Electronic Resource
    The potential for diazotrophy in iron- and sulfur-oxidizing acidophilic bacteria (1995)
    Springer
    Archives of microbiology 164 (1995), S. 294-300 
    Details
    ISSN: 1432-072X
    Keywords: Key words Acetylene reduction ; Nitrogen fixation ; Leptospirillum ferrooxidans ; Thiobacillus ferrooxidans
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Acetylene reduction was observed with ferrous-iron-oxidizing Thiobacillus ferrooxidans, as expected from previous studies with this bacterium. Acetylene reduction was also found during the growth of T. ferrooxidans on tetrathionate. Only Leptospirillum ferrooxidans, one of several other phylogenetically diverse, ferrous-iron- and/or sulfur-oxidizing acidophilic microorganisms, also reduced acetylene. A reduction of the oxygen concentration in the culture atmosphere was necessary to alleviate inhibition of nitrogenase activity. DNA sequences homologous to nif structural genes were found in both organisms. Diazotrophic growth of L. ferrooxidans was inferred from an increase in iron oxidation in ammonium-free medium when the oxygen concentration was limited and from apparent inhibition by acetylene under these conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002030050267
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 89
    Electronic Resource
    Electronic Resource
    GroEL chaperonins are required for the formation of a functional nitrogenase in Bradyrhizobium japonicum (1999)
    Springer
    Archives of microbiology 171 (1999), S. 279-289 
    Details
    ISSN: 1432-072X
    Keywords: Key words Cpn60 ; groESL ; Heat shock protein ; Hsp60 ; NifA ; Nitrogen fixation ; Symbiosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract At least five highly conserved, but disparately regulated groESL operons are present in Bradyrhizobium japonicum. Expression of groESL 3 is coregulated with symbiotic nitrogen fixation genes, implying a role of GroESL chaperonins in the nitrogen fixation process. Null mutants of individual groEL genes, however, were not impaired in symbiotic nitrogen fixation activity. By contrast, the groEL 3-plus-groEL 4 double mutant strain D4, which is mutated in those groEL genes that contribute most to the GroEL pool under symbiotic conditions, exhibited less than 5% Fix activity as compared to the wild-type. Expression of lacZ fusions made to several representative nif and fix genes was not, or only marginally, reduced in mutant D4, indicating that the requirement of chaperonins for nitrogen fixation does not occur at the level of RegSR-NifA-σ54- or FixLJ-FixK2-dependent gene regulation. Instead, immunoblot analyses revealed that the level of NifH and NifDK nitrogenase proteins was drastically decreased in extracts prepared from D4 bacteroids and from free-living cells grown anaerobically. Transcriptional fusions of the anaerobically induced groESL 3 promoter (P3) to all five B. japonicum groESL operons and also to groESL from Escherichia coli were integrated into the chromosome of mutant D4. Strains harboring P3 fused to groESL 1, groESL 2, groESL 5, or E. coli groESL partially complemented the symbiotic defect of mutant D4, whereas the wild-type phenotype was completely restored in strains complemented with P3 fused to groESL 3 (control) or groESL 4. Likewise, the growth defect of an E. coli groEL mutant could be corrected at least partially by individual B. japonicum groESL operons. In conclusion, both series of complementation analyses were not indicative of a strict substrate specificity of any of the B. japonicum groESL gene products, which is in good agreement with their high degree of sequence conservation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002030050711
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 90
    Electronic Resource
    Electronic Resource
    Nitrogen fixation associated with a hotspring green alga (1980)
    Springer
    Archives of microbiology 124 (1980), S. 161-167 
    Details
    ISSN: 1432-072X
    Keywords: Nitrogen fixation ; Photosynthesis ; Green alga ; Chl a and b ; DCMU ; Light and O2 dependency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A unicellular alga which can grow in the light without a combined nitrogen source was isolated from a hot spring. The cells were almost spherical, usually 5–10 μm in diameter. Absorption spectra of the watersoluble pigments and of the acetone-extracted ones revealed the existence of chlorophyll a and b and the absence of phycobilins. Thin sections examined by electron microscopy revealed an eukaryotic organization with features typical of the coccoid green algae (the Chlorococcales). Cells divided by internal cytokinesis and subsequent liberation of daughter cells from the parental wall, in a way similar to Chlorella. The alga reduced acetylene to ethylene and incorporated 15N2 into cell protoplasm when incubated in a low oxygen atmosphere. Nitrogenase activity was light-dependent, microaerophilic and thermophilic. Although the association of symbiotic nitrogen fixing prokaryotes with the cells may still be possible, any such organisms have not so far been detected.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00427722
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 91
    Electronic Resource
    Electronic Resource
    Expression of klebsiella his and nif genes in serratia marcescens, Erwinia herbicola and Proteus mirabilis (1980)
    Springer
    Archives of microbiology 127 (1980), S. 115-118 
    Details
    ISSN: 1432-072X
    Keywords: Proteus mirabilis ; Serratia marcescens ; Erwinia herbicola ; Nitrogen fixation ; nif genes ; his genes ; Plasmids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Plasmid pRD1, an R plasmid of the P incompatibility group which carries his and nif genes from Klebsiella pneumoniae in addition to drug resistance markers derived from RP4, was transferred to His- mutants of Serratia marcescens, Erwinia herbicola and Proteus mirabilis. His+ transconjugants were obtained at low but different frequencies according to recipient genus. Transconjugants all acquired the drug resistance, and were Nif+ in S. marcescens and E. herbicola, having acetylene-reducing activities of the same order of magnitude as the parent K. pneumoniae and fixing 15N2. No evidence for nif expression in P. mirabilis transconjugants was obtained though the nif genes were present.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00428014
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 92
    Electronic Resource
    Electronic Resource
    Mutants of Rhizobium japonicum defective in nodulation (1982)
    Springer
    Archives of microbiology 132 (1982), S. 219-224 
    Details
    ISSN: 1432-072X
    Keywords: Rhizobium ; Nitrogen fixation ; Nodules ; Soybean
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Several mutants defective in nodulation were isolated from Rhizobium japonicum strains 3I1b110 and 61A 76. Mutants of class I do not form nodules after incubation with soybean [Glycine max (L.) Merrill] for 17 days, but will do so by 28 days. When host plants other than G. max are infected with several of these strains, there is no detectable difference in the time of nodulation or size of nodules as compared to the wild type. Two mutants of class I (i. e., SM1 and SM2) have been shown previously to be altered in the lipopolysaccharide portion of their cell wall. Mutants of class II are not slow to nodulate but form fewer nodules than the wild type on all the host plants tested. Mutants of class III are unable to form nodules. Some bacteriophage-resistant mutants, altered in cell surface structure, fall into this class. Two mutants of class III do not bind to soybean roots.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00407954
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 93
    Electronic Resource
    Electronic Resource
    Nitrogen fixation and nitrate utilization by marine and freshwater Beggiatoa (1982)
    Springer
    Archives of microbiology 133 (1982), S. 172-177 
    Details
    ISSN: 1432-072X
    Keywords: Beggiatoa ; Nitrogen fixation ; Acetylene reduction ; Nitrate assimilation ; Microaerobic ; Isolation of marine strains
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Four newly isolated marine strains of Beggiatoa and five freshwater strains were tested for nitrogen fixation in slush agar medium. All strains reduced acetylene when grown microaerobically in media containing a reduced sulfur source and lacking added combined nitrogen. The addition of 2 mmol N, as nitrate or ammonium salts, completely inhibited this reduction. Although not optimized for temperature or cell density, acetylene reduction rates ranged from 3.2 to 12 nmol·mg prot-1 min-1. Two freshwater strains did not grow well or reduce acetylene in medium lacking combined nitrogen if sulfide was replaced by thiosulfate. Two other strains grew well in liquid media lacking both combined nitrogen and reduced sulfur compounds but only under lowered concentrations of air. All freshwater strains grew well in medium containing nitrate as the combined nitrogen source. Since they did not reduce acetylene under these conditions, we infer that they can assimilate nitrate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00414997
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 94
    Electronic Resource
    Electronic Resource
    The role of formate metabolism in nitrogen fixation in Rhizobium Spp. (1982)
    Springer
    Archives of microbiology 133 (1982), S. 312-317 
    Details
    ISSN: 1432-072X
    Keywords: Rhizobium japonicum ; Rhizobium leguminosarum ; Formate metabolism ; Formate dehydrogenase ; Nitrogen fixation ; Nitrogenase ; Bacteroids ; Symbiosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Formate metabolism supported nitrogen-fixation activity in free-living cultures of Rhizobium japonicum. However, formate0dependent nitrogense activity was observed only in the presence of carbon sources such as glutamate, ribose or aspartate which by themselves were unable to support nitrogenase activity. Formate-dependent nitrogenase activity was not detected in the presence of carbon sources such as malate, gluconate or glycerol which by themselves supported nitrogenase activity. A mutant strain of R. japonicum was isolated that was unable to utilise formate and was shown to lack formate dehydrogenase activity. This mutant strain exhibited no formate-dependent nitrogenase activity. Both the wild-type and mutant strains nodulated soybean plants effectively and there were no significant differences in the plant dry weight or total nitrogen content of the respective plants. Furthermore pea bacteroids lacked formate dehydrogenase activity and exogenously added formate had no stimulatory effect on the endogenous oxygen uptake rate. The role of formate metabolism in symbiotic nitrogen fixation is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00521297
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 95
    Electronic Resource
    Electronic Resource
    L-Methionine-SR-sulfoximine as a probe for the role of glutamine synthetase in nitrogenase switch-off by ammonia and glutamine in Rhodopseudomonas palustris (1983)
    Springer
    Archives of microbiology 134 (1983), S. 17-22 
    Details
    ISSN: 1432-072X
    Keywords: Nitrogen fixation ; Nitrogenase regulation ; Glutamine synthetase ; Methionine suofoximine ; Rhodospirillaceae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Methionine sulfoximine (MSX), an irreversible inhibitor of glutamine synthetase of Rhodopseudomonas palustris restored nitrogenase activity to cells in which nitrogenase had been completely inhibited by ammonia switch-off. After addition of MSX, there was a lag period before nitrogenase activity was fully restored. During this lag, glutamine synthetase activity progressively decreased, and near the time of its complete inhibition, nitrogenase activity resumed. Nitrogenase switch-off by ammonia thus required active glutamine synthetase. Glutamine itself caused nitrogenase inhibition whose reversal by MSX depended on the relative ratio of MSX to glutamine. Unlike ammonia, glutamine inhibited nitrogenase under conditions where glutamine synthetase activity was absent. This indicates that glutamine is the effector molecule in nitrogenase switch-off, for instance by interacting with the enzymatic system for Fe protein inactivation. The effects of glutamine and MSX were also dependent on the culture age. Possible explanation for this and for the competitive effects are a common binding site within the regulatory apparatus for nitrogenase, or, in part, within a common transport system. Some observations with MSX were extended to Rhodopseudomonas capsulata and agreed with those in R. palustris.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00429400
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 96
    Electronic Resource
    Electronic Resource
    Whole cell respiration and nitrogenase activities in Azotobacter vinelandii growing in oxygen controlled continuous culture (1983)
    Springer
    Archives of microbiology 134 (1983), S. 68-72 
    Details
    ISSN: 1432-072X
    Keywords: Azotobacter vinelandii ; Continuous culture ; Oxygen control ; Nitrogen fixation ; Respiratory protection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Azotobacter vinelandii strain OP was grown in continuous culture at various dissolved oxygen concentrations of air (100% air saturation of the medium=225 ±14 μM O2). Sucrose was added as carbon source and either dinitrogen or ammonia as nitrogen sources. Irrespective of the nitrogen source steady state cultures showed the following general responses with dissolved oxygen concentrations increasing from about 1% to 30% air saturation: (i) cell protein levels, (ii) the amount of cell protein formed per sucrose consumed as well as (iii) nitrogenase activity decreased by at least a factor of two while (iv) cellular respiration increased. At higher oxygen concentrations the parameters changed only slightly, if at all. Increasing the sucrose concentration in the inflowing medium (s R) from 3 g/l to 15 g/l increased the total level of cellular respiration with nitrogen-fixing cultures but was more pronounced with ammonium-assimilating cultures. With nitrogen-fixing cultures cell protein levels increased five-fold while the ratio of protein formed per sucrose consumed as well as cellular nitrogenase activity remained unaffected. With ammonium-assimilating cultures the cell protein level was only doubled and the level of cell protein formed per sucrose consumed was decreased at the higher s R. Increasing the dilution rate at a constant oxygen concentration of 45% air saturation resulted in an almost parallel increase of both cellular respiratory and nitrogenase activity at low and moderate dilution rates. At high dilution rates nitrogenase activity increased steeply over the respiratory activity. Nitrogen-fixing cultures adapted to various oxygen concentrations were subjected to oxygen stress by increasing the oxygen concentration for 7 min. In all cases, this resulted in a complete inhibition (‘switch-off’) of nitrogenase activity. Upon restoration of the original oxygen concentration nitrogenase activity returned to a decreased level. The discussion arrives at the conclusion that some of the results are incompatible with the concept of respiratory protection of nitrogenase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00429410
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 97
    Electronic Resource
    Electronic Resource
    Involvement of ammonium metabolism in the nitrate inhibition of nitrogen fixation in Anabaena sp. strain ATCC 33047 (1983)
    Springer
    Archives of microbiology 136 (1983), S. 81-83 
    Details
    ISSN: 1432-072X
    Keywords: Ammonia production ; Anabaena ; Cyanobacteria ; Nitrate reductase ; Nitrogen fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In the filamentous heterocystous cyanobacterium Anabaena sp. strain ATCC 33047 dinitrogen fixation and nitrate reduction are mutually exclusive processes. Nitrate promotes nitrate reductase synthesis and represses nitrogenase formation. Inhibition of ammonium assimilation by l-methionine-d,l-sulfoximine (MSX) alleviates the repressive effect of nitrate on nitrogenase synthesis, thus indicating that the nitrate effect is indirect through metabolites generated from the ammonium derived from nitrate reduction. In MSX-treated cells both nitrate reduction and dinitrogen fixation take place simultaneously, although at different sites of the filament, without any apparent competition for the required reducing power. The MSX-treated Anabaena cells generate ammonium from both nitrate and dinitrogen, simultaneously.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00404777
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 98
    Electronic Resource
    Electronic Resource
    Denitrification by Azospirillum brasilense Sp 7 (1984)
    Springer
    Archives of microbiology 138 (1984), S. 212-216 
    Details
    ISSN: 1432-072X
    Keywords: Denitrification ; Nitrate respiration ; Nitrous oxide reduction ; Nitrogen fixation ; Azospirillum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Nitrous oxide reduction can consistently be demonstrated with high activities in cells of Azospirillum brasilense Sp 7 which are grown anaerobically in the presence of low amounts of nitrite. Azospirillum can even grow anaerobically with nitrous oxide in the absence of any other respiratory electron acceptor. Nitrous oxide reduction by Azospirillum is inhibited by acetylene, amytal and weakly by carbon monoxide. Azospirillum converts nitrous oxide to molecular nitrogen without the formation of ammonia. The cells must, therefore, be supplied with ammonia from nitrogen fixation during anaerobic growth with nitrous oxide. When no other nitrogen compound besides nitrous oxide is available in the medium, the bacteria synthesize nitrogenase from protein reserves in about 2 h. Nitrogenase synthesis is blocked by chloramphenicol under these conditions. In contrast, the addition of nitrate or nitrite to the medium represses the synthesis of nitrogenase. Nitrous oxide reduction by Azospirillum and other microorganisms is possibly of ecological significance, because the reaction performed by the bacteria may remove nitrous oxide from soils.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00402122
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 99
    Electronic Resource
    Electronic Resource
    Transformations of inorganic nitrogen by Azospirillum spp. (1981)
    Springer
    Archives of microbiology 130 (1981), S. 96-100 
    Details
    ISSN: 1432-072X
    Keywords: Nitrogen fixation ; Nitrate respiration ; Denitrification ; Assimilatory nitrate reduction ; Dissimilatory nitrate reduction ; Acetylene reduction ; Azospirillum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Azospirillum spp. participate in all steps of the nitrogen cycle except nitrification. They can fix molecular nitrogen and perform assimilatory nitrate reduction and nitrate respiration. Culture conditions have been defined under which nitrate is used both as terminal respiratory electron acceptor and as nitrogen source for growth. Nitrate and, possibly to a very limited extent, nitrite, but not sulfate, iron or fumarate support anaerobic respiration. Under anaerobic conditions, nitrate can also supply energy for nitrogen fixation but without supporting growth. Nitrate-dependent nitrogenase activity lasts only for 3–4 h until the enzymes of assimilatory nitrate reduction are synthesized. Nitrite accumulates during this period and inhibits nitrogenase activity at concentrations of about 1 mM.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00411058
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 100
    Electronic Resource
    Electronic Resource
    Derivatives of Rhizobium meliloti strains carrying a plasmid of Rhizobium leguminosarum specifying hydrogen uptake and pea-specific symbiotic functions (1985)
    Springer
    Archives of microbiology 140 (1985), S. 352-357 
    Details
    ISSN: 1432-072X
    Keywords: Alfalfa ; Conjugation ; Cross inoculation ; Host specificity ; Hydrogen uptake ; Nodulation ; Nitrogen fixation ; Rhizobium ; Plasmids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract pIJ1008, a Rhizobium leguminosarum plasmid which determines hydrogen uptake ability and symbiotic functions in pea was transferable to three of seven natural isolates of R. meliloti tested. In these three strains, pIJ1008 was maintained stably with the respective sym megaplasmid indigenous to each R. meliloti strain. These strains carrying both plasmids nodulated alfalfa but not pea. By reisolation and examination of the strains from alfalfa nodule tissue, it was shown that pIJ1008 continued to be maintained but that pea-nodulation ability was suppressed. In one strain of R. meliloti which carries a 200 kb cryptic plasmid (in addition to a megaplasmid), the transfer and selection for pIJ1008 resulted in the loss of the cryptic plasmid. In three separate plant growth experiments, alfalfa nodules induced by each of the R. meliloti strain carrying both sym plasmids were assayed for hydrogen uptake activity. The average activity was 40-, 3.5-and 2-fold higher than with the respective pIJ1008-free strains. However, this higher activity was not accompanied by an increase in plant biomass or nitrogen content of shoots.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00446977
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...