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  • Gas chromatography  (39)
  • wheat  (39)
  • Escherichia coli  (33)
  • Springer  (111)
  • Cell Press
  • 2005-2009
  • 1985-1989  (111)
  • 1980-1984
  • 1988  (111)
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  • 2005-2009
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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Journal of industrial microbiology and biotechnology 3 (1988), S. 21-28 
    ISSN: 1476-5535
    Schlagwort(e): Diaper ; Staphylococcus aureus ; Escherichia coli ; Candida albicans
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Summary Methods were developed to study the effects of absorbent materials from diapers on microbial survival, growth and toxic shock syndrome toxin-1 (TSST-1) production under specified in vitro conditions. Growth of representative skin and fecal flora organisms was equivalent in cultures in which materials from cotton cloth diapers, disposable diapers or disposable diapers containing absorbent gelling material were added as the sole carbon source. In urine used as an enrichment medium, growth of the test organisms in media containing material from the three diaper types was equivalent and no contribution to growth from the diaper material was detected. TSST-1 was not produced byStaphylococcus aureus under conditions in which urine was added to the diaper materials. Pathogenic strains of organisms purposefully introduced onto diapers failed to survive and the few microbial cells normally found in diaper material did not multiply when stored under conditions favorable to microbial growth. The data indicate that all three diaper types tested were the same with respect to growth and survival of representative skin and fecal organisms.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Cellular and molecular life sciences 44 (1988), S. 848-853 
    ISSN: 1420-9071
    Schlagwort(e): DNA probes ; cytotoxin and enterotoxin genes ; Escherichia coli ; Shigella spp
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary DNA probes to identify the genes encoding toxins in enteric bacteria have been developed. Use of these probes reduces the number of animals required for toxicity testing, as suspect bacteria can be directly tested for the presence of toxin. We have augmented the gene probes available by developing probes against theEscherichia coli enterotoxin LTII and shiga toxin fromShigella dysenteriae 1. The LTII gene fromE. coli 357900 was identified and characterised and a suitable internal probe was obtained. The LTII gene was found not to be common among enterobacteriae from various geographical locations. Isolates predominately of animal origin from Nigeria and Thailand hybridized with the probe. The shiga toxin gene was isolated fromS. dysenteriae 1 by a combination of in vivo and in vitro methods. An internal probe was identified and used against different serogroups ofShigella andE. coli isolated. The probe was found to hybridize withS. dysenteriae 1 isolates and also someS. flexneri andS. sonnei strains. Representatives were tested for toxin production and found to produce toxin at low levels.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 46 (1988), S. 47-54 
    ISSN: 1570-7458
    Schlagwort(e): Coleoptera ; Curculionidae ; Sitophilus ; S. oryzae ; S. zeamais ; rice weevil ; maize weevil ; geographical strains ; digestion ; amylase ; diet ; barley ; corn ; maize ; rice ; wheat ; amylase inhibitors
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé La transformation de rang des valeur d'activité spécifique de l'α-amylase de 4 souches de S. oryzae et de 4 souches de S. zeamais montre que les niveaux les plus élevés de ces enzymes prédominantes s'observent chez les adultes nourris d'orge mondé ou de riz brun á grains longs. Des niveaux intermédiaires d'activité ont été obtenus chez les insectes élevés sur maïs jaune, et les niveaux les plus faibles chez ceux élevés sur blé. Bien que les extraits préparés à partir d'orge présentent une activité inhibitrice de deux isoamylases purifiées de S. oryzae, les niveaux des inhibiteurs naturels α-amylase de ces deux enzymes sont environ respectivement 2,2 et 6,1 fois plus concentrés dans le blé. L'ingestion de ces inhibiteurs d'amylase et la formation d'un complexe enzyme inactive/inhibiteur avec l'amylase secrétée antérieurement, peut rendre compte de la plus faible activité de l'amylase chez les charançons consommant du blé. Le niveau d'amylase de S. oryzae est 2 fois plus élevé que celui de S. zeamais pour toutes les souches élevées sur un régime donné. Des niveaux d'activité significativement différents ont été trouvés suivant les souches pour chacune des deux espèces. Puisque l'amylase est la principale hydrolase digestive de ces espèces, l'intensité de la modification des teneurs en amylase par la consommation de céréales peut indiquer leur adéquation comme hôtes potentiels.
    Notizen: Abstract Rank transformation of specific activity values of α-amylase across four strains of Sitophilus oryzae (L.) and four strains of S. zeamais Motschulsky indicates that levels of these predominant enzymes are highest in adults feeding on hulled barley or long-grain brown rice. Intermediate activity levels are found in weevils feeding on yellow corn (maize) and lowest levels are found in wheat-fed weevils. Although extracts prepared from barley contain inhibitory activity against two purified isoamylases from S. oryzae, levels of the naturally-occurring α-amylase inhibitors against these two enzymes are about 2.2-fold and 6.1-fold, respectively, more concentrated in wheat. Ingestion of these amylase inhibitors and formation of an inactive enzyme:inhibitor complex with previously secreted amylase may account for the lower activity of amylase in weevils of both species feeding on wheat. Amylase levels across all strains feeding on a given diet are about 2-fold higher in S. oryzae than in S. zeamais. Significant differences in activity levels were also found between strains in both species. Since α-amylase is a predominant digestive hydrolase in these species, the degree to which cereal diets affect amylase levels may indicate their suitability as potential hosts.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    ISSN: 1573-0832
    Schlagwort(e): odors ; volatiles ; microflora ; fungi ; wheat ; seasonality
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The fungal odor compounds 3-methyl-l-butanol, l-octen-3-ol and 3-octanone were monitored in nine experimental bins in Winnipeg, Manitoba containing a hard red spring wheat during the autumn, winter and summer seasons of 1984–85. Quality changes were associated with seed-borne microflora and moisture content in both ventilated and non-ventilated bins containing wheat of 15.6 and 18.2% initial moisture content. All three odor compounds occurred in considerably greater amounts in bulk wheat in non-ventilated than in ventilated bins, particularly in those with wheat having 18.2% moisture content. The presence of these compounds usually coincided with infection of the seeds by the fungi Alternaria alternata (Fr.) Keissler, Aspergillus repens DeBarry, A. versicolor (Vuill.) Tiraboschi, Penicillium crustosum Thom, P. oxalicum Currie and Thom, P. aurantiogriseum Dierckx, and P. citrinum Thom. High production of all three odor compounds in damp wheat stored in non-ventilated bins was associated with heavy fungal infection of the seeds and reduction in seed germinability. High initial moisture content of the harvested grain accelerated the production of all three fungal volatiles in non-ventilated bins.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Nutrient cycling in agroecosystems 17 (1988), S. 147-151 
    ISSN: 1573-0867
    Schlagwort(e): time of zinc application ; wheat ; zinc sulphate ; zinc oxide ; zinc uptake
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Field experiments with wheat were conducted for two years on flood plain alluvial soils to study the effectiveness of soil application of zinc sulphate and zinc oxide at 0, 15, 45, 60, 75 and 90 days after sowing. Yield and zinc uptake of wheat increased significantly with the application of zinc. Delaying the application of both zinc sulphate and zinc oxide up to 45 days of sowing did not adversly affect the zinc nutrition of wheat. However, delaying the application for 75 or 90 days after sowing eliminated the response. Zinc sulphate, when applied within 60 days of sowing performed better than zinc oxide. In a laboratory study, zinc sulphate maintained a higher level of zinc in the soil solution than zinc oxide at least over a 3-week period.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Nutrient cycling in agroecosystems 17 (1988), S. 137-146 
    ISSN: 1573-0867
    Schlagwort(e): Ammonium-nitrate-potassium interaction ; accumulation of reduced nitrogen ; wheat ; nitrification inhibitor ; grain ; stover
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A greenhouse experiment with wheat in 3L pots filled with a sandy loam soil in a factorial design was conducted to determine the effect of potassium on nitrogen utilization. Nitrogen was applied in three NH4-N/NO3-N ratios, 0/100, 25/75 and 50/50, at three levels: 0.75, 1.50 and 3.00gN/pot, and potassium was applied at three levels: 0, 0.5 and 1.0gK/pot. The higher levels of nitrate nitrogen with or without potassium reduced dry matter yields drastically, while the same levels of a NH4-N/NO3-N mixture of 50/50 with applied potassium reduced yields only slightly. Highest grain yield and total yield were obtained with a 25/75 mixture of ammonium/nitrate nitrogen with added potassium. Potassium addition to soil increased the utilization of nitrogen fertilizers, particularly when the ratio of ammonium to nitrate was increased. The highest uptake of reduced nitrogen was at the highest level of the ammonium to nitrate nitrogen ratio (50/50) when potassium was applied. Tillering was enhanced by an increased ammonium ratio in the nitrogen mixture, and by potassium.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    ISSN: 1573-0867
    Schlagwort(e): farmyard manure ; maize ; nitrogen ; phosphorus ; rice ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Field experiments with rice-wheat rotation were conducted during five consecutive years on a coarse-textured low organic matter soil. By amending the soil with 12t FYM ha−1, the yield of wetland rice in the absence of fertilizers was increased by 32 per cent. Application of 80 kg N ha−1 as urea could increase the grain yield of rice equivalent to 120 kg N ha−1 on the unamended soil. Although the soil under test was low in Olsen's P, rice did not respond to the application of phosphorus on both amended and unamended soils. For producing equivalent grain yield, fertilizer requirement of maize grown on soils amended with 6 and 12 t FYM ha−1 could be reduced, respectively to 50 and 25 per cent of the dose recommended for unamended soil (120 kg N + 26.2 kg P + 25 kg K ha−1). Grain yield of wheat grown after rice on soils amended with FYM was significantly higher than that obtained on unamended soil. In contrast, grain yield of wheat which followed maize did not differ significantly on amended or unamended soils.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Nutrient cycling in agroecosystems 17 (1988), S. 165-176 
    ISSN: 1573-0867
    Schlagwort(e): Low-grade phosphate rock ; acid extracts ; P fertiliser ; available P ; wheat ; soil pH
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Low grade phosphate rock (PR), containing high amounts of oxides of iron and aluminium is neither suitable for fertiliser production nor useful for direct application to annual crops. The fertiliser effectiveness of P extracted by H2SO4 from a low-grade phosphate rock, PR (Christmas Island C-grade PR) was evaluated for wheat (Triticum aestivum L.) on a calcareous loam (pH 8.4) and a non-calcareous loam (pH 6.9) in field and glasshouse experiments. Superphosphate was used to compare the performance of the acid extracts of PR. In the non-calcareous loam soil, crop establishment and yield were significantly reduced by the acid extracts of PR due to increased acidity. In the calcareous soil, however, the acid extracts of PR performed as well as superphosphate; similar or even higher crop yields were obtained with the former, especially when applied near the seed. The acid extracts of low-grade PR may, therefore, have a role in calcareous soils, where the extract can be applied directly or added in the irrigation waters to supply P to crops.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Nutrient cycling in agroecosystems 16 (1988), S. 137-155 
    ISSN: 1573-0867
    Schlagwort(e): Superphosphate ; rock phosphate ; wheat ; oats ; barley ; field experiment
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Nine soil tests for phosphate were evaluated for predicting the yield and P content of wheat, barley and oats grown on a sandy soil in Western Australia: Olsen, modified Olsen 1 (soil:solution ratio 1:5), modified Olsen 2 (soil:solution ratio 1:50), Colwell, Bray 1, Bray 2, modified Bray 2T (shaking time 10 minutes), modified Bray 2C (pH 3.7) and lactate. The soil had been fertilized 5 years previously with 20 levels each of superphosphate (OSP, range 0 to 400 kg P ha−1) and Queensland rock phosphate (QRP, range 0 to 20 000 kg P ha−1). For each species and fertilizer taken separately, all the tests, except for lactate, gave a good prediction of yield. When data for OSP and QRP were pooled, Bray 2 and modified Bray 2T tests were unsatisfactory predictors of both yield and P content. A linear relationship (P 〈 0.05) between mean soil tests value (χ) and the standard deviation (σ χ ) of the test value was observed for each soil test. For QRP, the results for lactate were the most variable (i.e.σχ/χ was greatest) followed by modified Olsen 2 〉 Bray 1 〉 Bray 2 〉 Olsen 〉 modified Bray 2C 〉 modified Olsen 1 〉 modified Bray 2T 〉 Colwell. The order for OSP fertilized soil was Bray 1 〉 modified Bray 2T 〉 Bray 2 〉 Olsen 〉 Colwell 〉 modified Bray 2C 〉 modified Olsen 1 〉 lactate 〉 modified Olsen 2. For combined OSP and QRP data, the results of the Olsen 1 and Colwell extractions were the least variable. Errors in the prediction of yield (σ Y ) for all crops resulting from an error in soil test values (σχ) were calculated. For OSP-fertilized soil variability in values for the Bray-1 test provided the highest error (about 16%) in the prediction of the yield, followed by Bray 2 (12%) 〉 Bray 2T (10%) 〉 Olsen (8%) 〉 Colwell (7%) 〉 modified Bray 2C (6%) 〉 lactate (4%). Maximum error was at yields of about 65% of maximum yield. For soil fertilized with QRP, lactate provided the highest error (about 10%) in the prediction of yield, followed by the other tests (〈 6%). Maximum error was at yields of about 35% of maximum yield. The Colwell soil test gave the most accurate overall prediction of yield for both fertilizers.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 149 (1988), S. 232-239 
    ISSN: 1432-072X
    Schlagwort(e): Turgor ; Glycine betaine ; K+ ; Escherichia coli
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The accumulation of glycine betaine to a high internal concentration by Escherichia coli cells in high osmolarity medium restores, within 1 h, a subnormal growth rate. The experimental results support the view that cell adaptation to high osmolarity involves a decrease in the initiation frequency of DNA replication via a stringent response; in contrast, glycine betaine transport and accumulation could suppress the stringent response within 1–2 min and restore a higher initiation frequency. High osmolarity also triggers the cells to lengthen, perhaps via an inhibition of cellular division; glycine betaine also reverses this process. It is inferred that turgor could control DNA replication and cell division in two separate ways. Glycine betaine action is not mediated by K+ ions as the internal level of K+ ions is not modified significantly following glycine betaine accumulation.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 11
    ISSN: 1432-072X
    Schlagwort(e): Clostridium thermoaceticum ; Formyltetrahydrofolate synthetase ; Cloning ; Escherichia coli ; Thermostable protein ; Expression ; Acetogen
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Formyltetrahydrofolate synthetase (FTHFS) (EC 6.3.4.3), a thermostable protein of four identical subunits from Clostridium thermoaceticum was cloned into Escherichia coli SK1592. The clone (CRL47) contained a 9.5 kb EcoRI fragment of C. thermoaceticum DNA ligated into pBR322. It produced catalytically active, thermostable FTHFS, that was not found in E. coli SK1592 containing native pBR322. The identity of the expressed enzyme was confirmed by specific binding of rabbit polyclonal anti-FTHFS serum produced against C. thermoaceticum FTHFS. The specific activities (μmol·min-1·mg-1) of FTHFS in cell free extracts of CRL47 were 28–89 when assayed at 50°C and pH8. This was from 3–10-fold higher than in C. thermoaceticum extracts. FTHFS was purified to homogeneity from CRL47. The purified enzyme behaved during electrophoresis and gel chromatography and it had similar specific activity and thermostability as the enzyme purified from C. thermoaceticum.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 12
    Digitale Medien
    Digitale Medien
    Springer
    Archives of microbiology 150 (1988), S. 499-503 
    ISSN: 1432-072X
    Schlagwort(e): Menaquinone ; Demethylmenaquinone ; Anaerobic respiration ; fnr gene ; Escherichia coli
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Escherichia coli grown with glucose in the absence of added electron acceptors contained 3–4 times more naphthoquinones (menaquinone plus demethylmenaquinone) than in the presence of O2. Presence of electron acceptors resulted in a slight additional increase of the naphthoquinone content. A strain defective in the fnr gene, which encodes the transcriptional activator of anaerobic respiration, showed the same response. With fumarate or dimethyl sulfoxide present, 94% of the naphthoquinones consisted of menaquinone, while with nitrate up to 78% was demethylmenaquinone. With trimethylamine N-oxid as the acceptor the proportion was intermediate. From the donor substrates of anaerobic respiration only glycerol had a significant influence on the ratio of the contents of the 2 quinones. It is concluded that FNR, the gene product of the fnr gene, is not required for anaerobic derepression of naphthoquinone viosynthesis. Menaquinone appears to be involved specifically in the respiration with fumarate or dimethyl sulfoxide, and demethylmenaquinone in nitrate respiration. Both naphthoquinones appear to serve in trimethylamine N-oxide respiration.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 13
    ISSN: 1432-072X
    Schlagwort(e): d-Cysteine desulfhydrase ; Cytosolic location ; 3-chloro-d-alanine sensitive ; 3-chloro-d-alanine dehydrochlorinase ; Escherichia coli
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract d-Cysteine desulfhydrase of Escherichia coli W3110 ΔtrpED102/F′ ΔtrpED102 was physiologically characterized. It was found to be located in the cytosolic fraction, as 3-chloro-d-alanine dehydrochlorinase is. d-Cysteine desulfhydrase catalyzed not only the α,β-elimination reaction of O-acetyl-d-serine to form pyruvate, acetic acid and ammonia, but also the β-replacement reaction of O-acetyl-d-serine with sulfide to form d-cysteine. However, these reactions appeared not to proceed in vivo. No other activity of d-cysteine synthesis from O-acetyl-d-serine and sulfide was detected in a crude cell extract of E. coli which was immunotitrated with antibodies raised against the purified d-cysteine desulfhydrase. Although d-cysteine desulfhydrase catalyzes the degradation (α,β-elimination reaction) of 3-chloro-d-alanine, which is an effective antibacterial agent, E. coli W3110 ΔtrpED102/F′ ΔtrpED102 did not show resistance against 3-chloro-d-alanine. Therefore, d-cysteine desulfhydrase does not contribute to 3-chloro-d-alanine detoxification in vivo.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 14
    ISSN: 1432-072X
    Schlagwort(e): Osmoadaptation ; Potassium uptake ; Glutamate synthesis ; Trehalose synthesis ; Internal pH ; Membrane potential ; Protonmotive force ; Proline uptake ; ProP system ; acr A-mutant ; Escherichia coli
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The sequence of events following the addition of 0.5 M NaCl to cells of Escherichia coli growing in a minimal mineral medium was investigated. Immediately after upshock the cells took up a large amount of K+ and synthesized approximately half the equivalent amount of glutamate concomitantly. After 30 min the cells started to synthesize trehalose, and after 2 h they had replaced most of their initial osmoprotectants by the carbohydrate. Cell trehalose was rapidly replaced by proline, taken up from the medium when added to the osmoadapting cells. The initial rate of this proline uptake was extremely rapid, and with rates observed of up to 0.6 mmolxmin-1xg-1 of cell protein it was approximately ten times faster than that reported in the literature for non-growing cells. These results indicate that for osmoadaptation of growing cells of E. coli the uptake of proline has priority over the synthesis of trehalose, which in its turn is preferred above K+ and glutamate as osmoprotectants. We observed that two mutants with unknown lesions, but which are known to be impaired in osmoadaptation, were inhibited in replacing K+ and glutamate by trehalose, indicating that this is the basis for their defect in osmoadaptation. Further experiments revealed that neither internal pH nor the membrane potential nor the transmembrane protonmotive force are likely to be involved in osmoadaptation in E. coli. However, during osmoadaptation a high internal potassium concentration appeared to stimulate the derepression of proline-uptake systems (mainly system ProP).
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 15
    ISSN: 1573-4919
    Schlagwort(e): Cytochrome P-450BM-3 ; Bacillus megaterium ; Escherichia coli ; protein charachterization ; recombinant DNA ; monoxygenase
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Summary In two previous reports (Narhi LO, Fulco AJ, J. Biol. Chem. 261: 7160–7169, 1986; Ibid., 262: 6683–6690, 1987) we described the characterization of a catalytically self-sufficient 119000-dalton P-450 cytochrome that was induced by barbiturates in Bacillus megaterium. In the presence of NADPH and O2, this polypeptide (cytochrome P-450BM-3) catalyzed the hydroxylation of long-chain fatty acids without the aid of any other protein. The gene encoding this unique monooxygenase was cloned into Escherichia coli and the clone harboring the recombinant plasmid produced a protein that behaved electrophoretically and immunochemically like the B. megaterium enzyme (Wen LP, Fulco AJ, J. Biol. Chem. 262: 6676–6682, 1987). We have now compared authentic P-450BM-3 from B. megaterium and putative P-450BM-3 isolated from transformed E. coli and have found them to be indistinguishable with respect to chromatographic and electrophoretic behavior, reaction with specific antibody, prosthetic group (heme, FAD and FMN) analyses, spectra, enzymology, limited trypsin proteolysis and partial amino acid sequencing. We thus conclude that the P-450 cytochrome expressed by the transformed E. coli is essentially identical to native P-450BM-3 induced by barbiturates in B. megaterium. The evidence furthermore suggests that the primary amino acid sequence of this complex protein is alone sufficient to direct the proper integration of the three prosthetic groups and to specify folding of the polypeptide into the correct tertiary structure.
    Materialart: Digitale Medien
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  • 16
    Digitale Medien
    Digitale Medien
    Springer
    Biochemical genetics 26 (1988), S. 693-703 
    ISSN: 1573-4927
    Schlagwort(e): wheat ; gliadins ; gel electrophoresis ; evolution ; genetic analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The gliadin composition of 78 spring durum wheat varieties has been studied by one-dimensional (Al-lactate,pH 3.1) and two-dimensional (first dimension, Al-lactate,pH 3.1; second dimension, sodium dodecyl sulfate-polyacrylamide gel) electrophoresis. Analysis of hybrids has shown that all components of the α zone of gliadin spectra are inherited together as blocks and are, probably, coded for by a cluster of tightly linked genes located on chromosome 6A. Fourteen variants of gliadin blocks have been identified, which can be classified into five families on the basis of component composition. All families but one have analogues among chromosome 6A-controlled blocks of bread wheat. The results indicate that some of the genome A diploid genotypes that were ancestors of durum wheats were also ancestors of bread wheats and that polyploid wheats were produced by repeated allopolyploidization events, as has been suggested earlier.
    Materialart: Digitale Medien
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  • 17
    Digitale Medien
    Digitale Medien
    Springer
    Biochemical genetics 26 (1988), S. 693-703 
    ISSN: 1573-4927
    Schlagwort(e): wheat ; gliadins ; gel electrophoresis ; evolution ; genetic analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The gliadin composition of 78 spring durum wheat varieties has been studied by one-dimensional (Al-lactate,pH 3.1) and two-dimensional (first dimension, Al-lactate,pH 3.1; second dimension, sodium dodecyl sulfate-polyacrylamide gel) electrophoresis. Analysis of hybrids has shown that all components of the α zone of gliadin spectra are inherited together as blocks and are, probably, coded for by a cluster of tightly linked genes located on chromosome 6A. Fourteen variants of gliadin blocks have been identified, which can be classified into five families on the basis of component composition. All families but one have analogues among chromosome 6A-controlled blocks of bread wheat. The results indicate that some of the genome A diploid genotypes that were ancestors of durum wheats were also ancestors of bread wheats and that polyploid wheats were produced by repeated allopolyploidization events, as has been suggested earlier.
    Materialart: Digitale Medien
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  • 18
    ISSN: 1573-5028
    Schlagwort(e): chloroplast ; cross-reaction ; Escherichia coli ; immunoblotting ; ribosome ; ribosomal protein S1
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Antibodies directed against E. coli ribosomal protein S1 were used in immunoblotting assays to search for an S1-like protein in the ribosome of spinach chloroplast. An immunological cross-reaction was reproducibly detected on the blots and inhibition experiments have demonstrated its specificity. The chloroplastic ribosomal protein which has epitopes common to antigenic determinants of the E. coli protein S1 was identified as being protein S2/S3.
    Materialart: Digitale Medien
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  • 19
    Digitale Medien
    Digitale Medien
    Springer
    Plant molecular biology 10 (1988), S. 303-310 
    ISSN: 1573-5028
    Schlagwort(e): chloroplast gene ; monocot ; psbA ; transcription ; wheat ; 5′ end
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We have mapped and cloned the wheat chloroplast gene (psbA) that encodes the 32 kd polypeptide of Photosystem II. The psbA gene is located in the large single copy region adjacent to one inverted repeat and is transcribed toward the latter. The sequence of the 5′ end of the wheat gene is homologous with dicot psbA genes. We have located the 5′ terminus of the wheat psbA RNA to a position 83 nt upstream of its coding region. The same psbA RNA species was capped in vitro by guanylyltransferase, establishing that its 5′ end is a transcription start site. Regions which resemble procaryotic -10 and -35 promoter elements are located immediately upstream of the wheat psbA transcription initiation site.
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  • 20
    Digitale Medien
    Digitale Medien
    Springer
    Plant molecular biology 11 (1988), S. 633-639 
    ISSN: 1573-5028
    Schlagwort(e): wheat ; triplet protein (triticin) ; legumin ; amino acid sequence homology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We have obtained several amino acid sequences from purified polypeptides of a wheat endosperm storage globulin previously described as ‘triplet’ protein. The amino acid sequence data supported by immunochemical analysis using anti-oat 12S globulin antibodies, provide definitive evidence that the triplet protein is homologous to pea legumin and related seed storage proteins of oats, rice and several dicotyledonous species. Thus, it is now proposed that the triplet protein of wheat be renamed ‘triticin’. The oat globulin antibodies also cross-reacted strongly with the high-molecular-weight (HMW) glutenin subunits which have been implicated in bread-making quality.
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  • 21
    Digitale Medien
    Digitale Medien
    Springer
    Plant molecular biology 11 (1988), S. 833-843 
    ISSN: 1573-5028
    Schlagwort(e): mitochondrial DNA ; transfer RNA genes ; rearrangement ; recombination ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In the course of isolating tRNA genes from wheat mtDNA, we have found the same tRNAPro gene in two different Hind III restriction fragments, H-P1 (0.7 kbp) and H-P2 (1.7 kbp). Sequences immediately flanking these duplicate genes are closely related, although not identical; sequence comparisons suggest that multiple rearrangements have occurred in the vicinity of the H-P2 tRNAPro gene, relative to the H-P1 version. The chimeric nature of H-P2 is emphasized by the presence of sequences that are also found upstream of the wheat mitochondrial 26S rRNA gene, as well as sequences derived from chloroplast DNA. Comparison of H-P2 with H-P1 plus upstream sequences provides some insight into possible molecular events that might have generated H-P2. In particular, such comparisons suggest a model in which the homologous sequences in H-P2 are seen to be derived from H-P1 plus upstream sequences as a result of an intragenomic, site-specific rearrangement event, followed by amplification of the product, its fixation in the mitochondrial genome, and subsequent sequence divergence (single base changes as well as insertions/deletions of up to 50 nucleotides). The results reported here implicate particular primary sequence motifs in certain of the rearrangements that characterize H-P2.
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  • 22
    Digitale Medien
    Digitale Medien
    Springer
    Plant molecular biology 10 (1988), S. 251-262 
    ISSN: 1573-5028
    Schlagwort(e): mitochondria ; mitochondrial DNA ; transfer RNA ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We have begun a systematic search for potential tRNA genes in wheat mtDNA, and present here the sequences of regions of the wheat mitochondrial genome that encode genes for tRNAAsp (anticodon GUC), tRNAPro (UGG), tRNATyr (GUA), and two tRNAsSer (UGA and GCU). These genes are all solitary, not immediately adjacent to other tRNA or known protein coding genes. Each of the encoded tRNAs can assume a secondary structure that conforms to the standard cloverleaf model, and that displays none of the structural aberrations peculiar to some of the corresponding mitochondrial tRNAs from other eukaryotes. The wheat mitochondrial tRNA sequences are, on average, substantially more similar to their eubacterial and chloroplast counterparts than to their homologues in fungal and animal mitochondria. However, an analysis of regions ∼ 150 nucleotides upstream and ∼ 100 nucleotides downstream of the tRNA coding regions has revealed no obvious conserved sequences that resemble the promoter and terminator motifs that regulate the expression of eubacterial and some chloroplast tRNA genes. When restriction digests of wheat mtDNA are probed with 32P-labelled wheat mitochondrial tRNAs, 〈20 hybridizing bands are detected, whether enzymes with 4 bp or 6 bp recognition sites are used. This suggests that the wheat mitochondrial genome, despite its large size, may carry a relatively small number of tRNA genes.
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  • 23
    Digitale Medien
    Digitale Medien
    Springer
    The journal of membrane biology 106 (1988), S. 183-202 
    ISSN: 1432-1424
    Schlagwort(e): proline transport ; proline utilization ; osmotolerance ; stress responses ; Escherichia coli ; Salmonella typhimurium
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Materialart: Digitale Medien
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  • 24
    Digitale Medien
    Digitale Medien
    Springer
    Theoretical and applied genetics 76 (1988), S. 933-940 
    ISSN: 1432-2242
    Schlagwort(e): Gliadin ; Two-dimensional electrophoresis ; F1 monosomic analysis ; chromosomal assignment ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The gliadin components from four bread wheat cultivars: Chinese Spring, Capelle Desprez, Holdfast and Pane-247 and their monosomic F1s for the chromosomes of homoeologous groups 1 and 6 have been analyzed by two-dimensional (2-pH) polyacrylamide gel electrophoresis. Chromosomal location of gliadin genes and the allelic differences were well established by analyzing the different F1 monosomic hybrids, electrophoretical patterns and differences in relative staining intensity. A new gliadin encoded by a gene located on chromosome 6B in Chinese Spring is described. The two-dimensional patterns of gliadin in the other three varieties and the chromosomal location of their genes are reported for the first time. Relationships between gliadins in the two-dimensional patterns and the traditional system for their nomenclature are discussed.
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  • 25
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 211 (1988), S. 176-182 
    ISSN: 1617-4623
    Schlagwort(e): Escherichia coli ; Colicin B immunity gene cbi
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Cells of Escherichia coli containing the cbi locus on plasmids are immune to colicin B which kills cells by dissipating the membrane potential through pore formation in the cytoplasmic membrane. The nucleotide sequence of the cbi region was determined. It contains an open reading frame for a polypeptide consisting of 175 amino acids. The amino acid sequence is homologous to the primary structure of the colicin A immunity protein. This, and the strong homology between the pore-forming domains of colicins A and B suggests a common evolutionary origin for both colicins. The immunity protein could be identified following strong overexpression of cbi. The electrophoretically determined molecular weight of 20 000 was close to the calculated molecular weight of 20 185. The protein contains four large hydrophobic regions. The immunity protein was localized in the membrane fraction and was mainly contained in the cytoplasmic membrane. It is proposed that the immunity protein inactivates the colicin in the cytoplasmic membrane.
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  • 26
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 212 (1988), S. 378-381 
    ISSN: 1617-4623
    Schlagwort(e): Inducible mutagenesis ; Regionally targeted UV mutagenesis ; Escherichia coli ; Phage M13
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Mutant forms of the glyU (glycyl tRNA) gene cloned in M13mp8 were subjected to uninduced targeted UV mutagenesis; i.e. phage particles were irradiated and used to infect unirradiated umuC + or irradiated umuC mutant cells. The irradiated phage carried GAG at the anticodon triplet and transitions to GAA were scored. The uninduced targeted mutation rate was reduced by altering the sequence of the gene in the vicinity of the target purine (Pu) residue. In particular a triplet of pyrimidines (PyPyPy) 5′ to the target G was changed to PyPuPy in order to prevent formation of cyclcobutane and 6-4 pyrimidine dimers close to the target. On this basis we suggest a mechanism for one type of uninduced regionally targeted UV mutagenesis.
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  • 27
    ISSN: 1617-4623
    Schlagwort(e): l-azetidine-2-carboxylate resistance ; Escherichia coli ; γ-glutamyl kinase ; Proline ; Saccharomyces cerevisiae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary We constructed plasmids carrying the Escherichia coli proB gene that encodes γ-glutamyl kinase, under the control of the yeast GAL1 promoter. This construction was carried out with both the wild-type proB + gene and a mutant allele, proB74, that specifies an enzyme resistant to feedback inhibition by proline. Yeast pro1 mutants harboring these plasmids are proline prototrophs. We conclude that the pro1 mutation results in a deficiency in the γ-glutamyl kinase activity in Saccharomyces cerevisiae. Expression of the proB74 allele in yeast resulted in enhanced resistance to the proline analogue l-azetidine-2-carboxylate and in a 2.4-fold elevation of the intracellular free proline levels. This result suggests that γ-glutamyl kinase is the rate limiting step in proline biosynthesis in yeast.
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  • 28
    ISSN: 1617-4623
    Schlagwort(e): Escherichia coli ; Dictyostelium ; DNA gyrase ; Deletion ; Plasmid
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary We constructed a recombinant plasmid containing the 2.1 kb HindIII fragment of plasmid pDG1, isolated from the cellular slime mold (Dictyostelium sp. strain GA11), and using pAG60 as cloning vector. We found that deletions of the recombinant plasmid took place frequently in Escherichia coli wild-type cells. However, the deletion was not observed when the plasmid was introduced into a strain that was an isogenic temperature-sensitive mutant of the gyrA gene. These results suggest that E. coli DNA gyrase is involved in the mechanisms of the deletion formation. It was shown that the 1.0 kb deletant derived from the 2.1 kb HindIII insert was produced by elimination of a 1.1 kb region. Sequence analysis of the deletants showed that cutting and rejoining took place between two out of the six nearly perfect direct repeats [21 bp palindromic sequences; AAAAAA(T/C)GGC(G/C)GCC(A/G)TTTTTT], located near the distal ends of the inverted repeats, preserving one copy of the repeats. These sequences consist of local short inverted repeats, where cutting and rejoining occur at one of the two regions.
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  • 29
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 213 (1988), S. 379-387 
    ISSN: 1617-4623
    Schlagwort(e): Stringent control ; RNA polymerase ; Escherichia coli
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Previous studies on two Escherichia coli rpoB mutants, carrying single amino acid substitutions at approximate amino acid positions 736 and 906 in the β subunit, showed that these alterations in the RNA polymerase resulted in an apparent reduced response to valine-induced amino acid starvation in vivo and prevented ppGpp-mediated inhibition of transcriptional initiation at stable RNA promoters in vitro. These observations suggested that the mutations had altered either the ppGpp binding site or the promoter selectivity of the enzyme. The in vivo analysis presented here indicates that these mutants encode an RNA polymerase that responds normally to changes in the level of ppGpp; their apparent relaxedness is due to a reduced accumulation of ppGpp during isoleucine starvation. Thus, there is no indication that the mutations have altered ppGpp binding sites. These observations and the difference between in vitro and in vivo results can be explained by the assumption that the mutations produce an extended ppGpp-dependent pausing of RNA polymerase during the transcription of unstable RNA. Comparison of the vivo and in vitro effects of ppGpp on rrn transcription further suggests that these reflect different phenomena, although in both cases ppGpp inhibits rrn transcription.
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  • 30
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 214 (1988), S. 62-67 
    ISSN: 1617-4623
    Schlagwort(e): Mutagenesis ; Inosine ; Escherichia coli
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Two complementary 24 base single stranded oligonucleotides containing randomly located inosine residues were synthesized in vitro. Once annealed, the two oligonucleotides were cloned into derivatives of ColE1 and transformed into Escherichia coli. Sequence analysis of 157 clones yielded 305 mutations. The pattern of the mutations revealed the following: (1) The frequency of inosine induced mutations was significantly less than predicted from its content in the oligonucleotides; (2) Inosine incorporation resulted almost exclusively in base changes to guanine; (3) The mutation distribution is biased towards A/T to G/C substitutions; (4) There were reproducible position biases; and (5) There was a reproducible strand bias which was independent of the cassette orientation with respect to the plasmid origin of replication.
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  • 31
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 214 (1988), S. 460-466 
    ISSN: 1617-4623
    Schlagwort(e): N-ethyl-N′-nitro-N-nitrosoguanidine ; 1-(2-hydroxyethyl)-1-nitrosourea ; Mutations ; Escherichia coli ; DNA sequencing
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary DNA sequencing was used to determine the specific types of DNA base changes induced following in vivo exposure of Escherichia coli to the ethylating agent N-ethyl-N′-nitro-N-nitrosoguanidine (ENNG) and the hydroxyethylating agent 1-(2-hydroxyethyl)-1-nitrosourea (HENU) using the xanthine guanine phosphoribosyltransferase (gpt) gene as the genetic target. We observed that 22/30 of the ENNG-induced mutations were GC→AT transitions, 4/30 were AT→GC transitions, 3/30 were AT→TA transversions, and 1/30 was an AT→CG transversion. We observed that 37/40 HENU-induced mutations were GC→AT transitions and that the remaining 3/40 were AT→GC transitions. A majority of the GC→AT transitions induced by ENNG and HENU (68% and 73%, respectively) occurred at the second guanine of the sequence 5′-GG(A or T)-3′; this sequence specificity was similar to that previously seen with the alkylating agents N-methyl- and N-ethyl-N-nitrosourea (MNU and ENU) and N-methyl-N′-nitro-N-nitrosoguanidine (MNNG). A DNA strand preference for the G→A changes (antisense strand), previously noted for MNU, ENU, and MNNG, was observed following exposure to HENU and ENNG. The AT→GC transitions induced by ENNG, HENU, and ENU also exhibit a sequence specificity with 13/13 mutations occurring at the T of the sequence 5′-NTC-3′. A strand preference was not apparent for these mutations.
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  • 32
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 213 (1988), S. 99-104 
    ISSN: 1617-4623
    Schlagwort(e): Promoters ; Escherichia coli ; Proteus vulgaris ; Hemolysin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The hemolytic activity of Escherichia coli and Proteus vulgaris is determined by common contiguous genes encoding synthesis (hly C, hly A) and specific secretion (hly B, hly D) of active hemolysin. Nevertheless, the hlyC-proximal DNA sequences directing production of the homologous hemolysins by the recombinant DNAs P. vulgaris pVU763-709 and E. coli pANN202-312 showed no extensive homology. Primer extension and S1 nuclease protection were used to define in the two sequences the 5′ termini of hly transcripts synthesized in vivo and thus to infer the active hly promoters sequences. The E. coli hly C upstream region contained three separate promotors directing in vivo hly transcription, while the corresponding transcription of the P. vulgaris hly operon originated from a single distinct promotor, the-35 and-10 sequences of which formed part of an inverted repeat sequence. Elevated hemolytic activity caused by upstream Tn5 insertions in pVU763-709 resulted from increased transcription from this promotor.
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  • 33
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 214 (1988), S. 148-152 
    ISSN: 1617-4623
    Schlagwort(e): RNA polymerase ; Transcription ; Positive regulation ; Escherichia coli
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The specificity of the transcription defect caused by the rpoA341 (phs) allele has been investigated. Three apparently unlinked genetic systems have been found to be impaired in their transcription by this mutant allele of the alpha subunit of RNA polymerase. These three systems, the melAB operon the cysA locus and the ara regulon, are apparently unrelated other than by their requirement for a regulon-specific positive regulator for the initiation of transcription. Expression of the gene for the positive regulator does not appear to be significantly affected in any of the three systems. However, mutations that render expression of the araBAD operon independent of the regulatory protein also confer insensitivity to the rpoA341 allele. The siginificance of these observations is discussed in the context of models of positive regulation.
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  • 34
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 215 (1988), S. 156-160 
    ISSN: 1617-4623
    Schlagwort(e): Ionising radiation ; Gene cloning ; DNA repair ; Escherichia coli ; Mitomycin C
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A segment of the Escherichia coli genome which complements the ionising radiation sensitivity of the rorB mutation was cloned into pBR322. This DNA segment also complements the mitomycin C sensitivity of the rorB mutation. The gene was subcloned until defined in a fragment of 1.05 kb. Only one gene product, a protein of approximately 16.5 kDa, was found on maxicell analysis of the various subclones. Iso-electric focusing of this gene product suggests it may function in a complex.
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  • 35
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 211 (1988), S. 1-7 
    ISSN: 1617-4623
    Schlagwort(e): Nalidixic acid resistance ; Quinolones ; gyrA ; Nucleotide sequence ; Escherichia coli
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary DNA fragments of 8.5 kb containing the gyrA gene were cloned from Escherichia coli KL-16 and from four spontaneous gyrA mutants which showed various levels of resistance to quinolones. The gyrA gene was situated at about 4 kb in front of the nrdA gene and transcribed counterclockwise on the E. coli chromosome. It encoded a polypeptide of 875 amino acids with a molecular weight of about 97000. The four gyrA mutations were located strikingly close to one another within a small region near the N-terminus of the gyrA polypeptide, i.e., nucleotide changes from C to T, from C to G, from G to T and from G to T at nucleotides 248, 248, 318 and 199, respectively, resulting in amino acid changes from Ser to Leu, from Ser to Trp, from Gln to His and from Ala to Ser at amino acids 83, 83, 106 and 67, respectively. These mutations were situated in the relatively hydrophilic regions of the GyrA polypeptide and close to Tyr at amino acid 122 which has been shown to be the site covalently bound to DNA.
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  • 36
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 211 (1988), S. 459-464 
    ISSN: 1617-4623
    Schlagwort(e): Chloroplast ; DNA-dependent RNA polymerase ; Initiation factor ; Transcription ; Escherichia coli
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The 80 000 x g supernatants of spinach leaf homogenates contain polypeptides that are immunologically related to the ββ′, α and σ subunits of Escherichia coli RNA polymerase. The σ-like (90 kDa and 33 kDa) and α-like (38 kDa) polypeptides are separated from ββ′-like ones by chromatography on Heparin-Sepharose or Servacel-PEI. If a protein fraction containing the α- and σ-like polypeptides is added to transcriptionally active purified chloroplast polymerase (consisting of the ββ′-like 150/145 kDa and 80 kDa polypeptides and the 110/102 kDa polypeptides the latter two being not homologous to polypeptides of E. coli polymerase) a correct initiation and transcription of the spinach chloroplast rbcL gene is obtained. Chloroplast protein fractions containing the σ-like polypeptide(s) also enhance correct transcription initiation when they are combined with E. coli RNA polymerase.
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  • 37
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 212 (1988), S. 1-5 
    ISSN: 1617-4623
    Schlagwort(e): Cytochrome b 561 ; Diheme b-type cytochrome ; cybB gene ; Escherichia coli ; DNA sequence
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The complete nucleotide sequence of the Escherichia coli cybB gene for diheme cytochrome b 561 and its flanking region was determined. The cybB gene comprises 525 nucleotides and encodes a 175 amino acid polypeptide with a molecular weight of 20160. From its deduced amino acid sequence, cytochrome b 561 is predicted to be very hydrophobic (polarity 33.7%) and to have three membrane spanning regions. Histidines, canonical ligand residues for protohemes, are localized in these regions, and the heme pockets are thought to be in the cytoplasmic membrane. No significant homology of the primary structure of cytochrome b 561 with those of other bacterial b-type cytochromes was observed.
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  • 38
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 211 (1988), S. 320-325 
    ISSN: 1617-4623
    Schlagwort(e): Tn21 integrase ; Site-specific recombination ; Transposon evolution ; Escherichia coli
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The IncW plasmid R388 and the DNA region of Tn21 containing the Smr and the Sur genes are capable of RecA-independent recombination. This recombination occurs at a relatively high frequency (up to 10-4 recombinants per recipient molecule) and results in integration of the two plasmids. No detectable repeats are formed in the process. The crossover points have been confined to a 0.4-kb homologous segment in both plasmids which contains a 59-bp DNA sequence presumably involved in the acquisition of new genes by Tn21 and its relatives (Cameron et al. 1986). It is likely that the recombination occurs precisely at this point. At least one trans-acting function (an integrase) is required for the site-specific recombination. It has been localized to a 1456-bp BstEII-BamHI fragment of Tn21 and can efficiently complement the integration of plasmids containing the integration site.
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  • 39
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 214 (1988), S. 379-388 
    ISSN: 1617-4623
    Schlagwort(e): putP ; putA ; putC ; Escherichia coli ; Promoter regions of putA and putP
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The effects of regulatory proteins on the expression of putP and putA were studied using put-lacZ fusion genes. The expression of the putP-lacZ gene was activated by the glnG gene product and the catabolite gene activator protein (CAP). The putA gene product inhibited activation of putP-lacZ gene expression by CAP or the glnG gene product and its inhibition was greater in the absence of proline. The expression of the putA-lacZ gene was activated by CAP and repressed by the glnG gene product. The putA gene product acted as a repressor in the absence of proline, but not in its presence. Studies using put-lacZ fusion genes with upstream deletions showed that the region required for the activation of putP by CAP was within 234 bp upstream of the translational initiation site and that that for the activation of putP was within 107 bp upstream of the translational initiation site of the putA gene. This supported the suggested locations of CAP binding sites. The region required for induction of putP and putA expression by proline was located at the Hpal site 182 bp upstream of the translational starting site of putA, suggesting that a sequence of dyad symmetry located 1 bp to the left of the HpaI site is a candidate for the binding site of the putA gene product.
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  • 40
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Simultaneous distillation-extraction ; Cheese volatiles
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A simultaneous distillation-extraction apparatus proposed by Godefroot has been used for the GC study of volatile components of cheese. 5–10 g of cheese provide a fraction that can be directly injected into a GC or a GC/MS. Two capillary columns (SE-30 and SP-1000) were evaluated, the second one being adequate for quantitative determinations. Camphor was used as internal standard. The coefficients of variation ranged from 1.4 to 11.8. The technique can be used as a fast method for the characterization of cheeses from their volatile component concentrations.
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  • 41
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 1087-1088 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Log plot ; Homologous series
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The slope of the log plot of the adjusted retention time of a homologous series usually varies from that of the n-alkane series by no more than 2%, though with unusual interactions between the functional group and the stationary phase the difference may be as high as 7%.
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  • 42
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Preparative scale separations ; Plate model
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Two close-boiling materials, diethyl ether (DEE) and dichloromethane (DCM), were separated to investigate the effects of the pure components and the mixture on elution in preparative gas-liquid chromatography. Nitrogen was used as the carrier gas, and the chromatographic column (1 cm I.D. and 0.75m length) was packed with Chromosorb A with different quantities of dinonyl phthalate stationary phase and particle sizes. Below ca. 7% (by wt.) of feed concentration, the experimental elution curves of pure DEE and DCM were almost the same as those of the mixture, and the theoretical plate model can be used successfully to predict the elution curves.
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  • 43
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 404-408 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Silica surface modification ; Hexamethylcyclotrisilazane ; Hexamethyldisilazane ; Support materials
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The paper is concerned with the structure of an organic layer bonded to the silica surface modified with silazanes. The changes of the retention volumes of hydrocarbons is studied for the silicas modified with hexamethylcyclotrisilazane, hexamethyldisilazane and their mixtures. It is shown that most of the carbon in the layer after hexamethylcyclotrisilazane modification is bonded to the surface by Si−O−Si bonds. This fact supports the assumption of a fragmentation of the cyclosilane used for modification.
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  • 44
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 389-392 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Statistical criteria ; Non-linear models ; Constants for n-alkane retention curve ; Multiparametric least-squares adjustment
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Multiparametric, least-squares, regression treatment of G.C. data is extended to describe deviations from the usual linear model. Through statistical evaluation of results, four parameters models are generally found adequate and the use of higher degree empirical models is discouraged.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 45
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 539-542 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Temperature programming ; Retention index
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A method is presented for the calculation of retention indices at an assigned temperature from temperature-programmed data. If the retention times at two different program rates for the solutes and the n-alkanes are known, the retention indices at an assigned temperature can be calculated directly.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 46
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 26 (1988), S. 125-132 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Non-equilibrium frontal chromatography ; Nonlinear isotherms ; Variable velocity ; Multicomponent mixtures
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The paper presents a classification of various theoretical models for multicomponent gas chromatography at u=var for high concentrations of the mixture components with consideration of the major distinctive features of the interphase mass exchange inside the porous grains of the adsorbent and outside them within the porous medium of the chromatographic column. It has been shown that the conditions determining a given front behaviour of multicomponent gas mixture at u=var depend on: theoretical models for the kinetics and dynamics of adsorption; the values of mass exchange parameters inside the porous grains and in the porous medium. Formulae have been derived for calculating the values of the quantities characterising the frontal behaviour in the stage of adsorption and desorption of multicomponent mixture at u=var.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 47
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 211 (1988), S. 138-142 
    ISSN: 1617-4623
    Schlagwort(e): Escherichia coli ; DnaA ; Replication initiation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Overexpression of DnaA protein from a multicopy plasmid accompanied by a shift to 42°C causes initiation of one extra round of replication in a dnaA + strain grown in glycerol minimal medium. This extra round of replication does not lead to an extra cell division, such that cells contain twice the normal number of chromosomes.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 48
    ISSN: 1617-4623
    Schlagwort(e): Escherichia coli ; Recombination ; DNA repair ; recD
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary DNA repair and recombination were investigated in a recD mutant of Escherichia coli which lacked the nuclease activity of the RecBCD enzyme. The resistance of this mutant to ultraviolet (UV) light was shown to be a function of recJ. A recD recJ double mutant was found to be more sensitive to UV radiation than a recB mutant, whereas recD and recJ single mutants were resistant. Recombination in conjugational crosses with Hfr donors was also reduced in recD recJ strains, but the effect was modest in comparison with the sensitivity to UV. Within certain limits, mutations in recF, recN, recO, lexA and ruv did not affect sensitivity to UV and recombination in a recD mutant any more than in a recD + strain. The possibility that recD and recJ provide overlapping activities, either of which can promote DNA repair and recombination in the absence of the other, is discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 49
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 215 (1988), S. 165-172 
    ISSN: 1617-4623
    Schlagwort(e): Escherichia coli ; Repetitive protein ; Heterologous gene expression ; Protein engineering ; inaZ gene
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The ice nucleation gene inaZ, from Pseudomonas syringae S203, was manipulated to produce a series of defined rearrangements in its coding sequence without changing the reading frame. The effects of these mutations on the ice nucleation phenotype were determined in a heterologous host, Escherichia coli K12. Deletions which disrupted the periodicity of 16 codons, in a repetitive region of inaZ, caused the frequencies of ice nuclei in the bacterial population to be significantly depressed; the nuclei with thresholds at warmer temperatures were most affected. In contrast, when the periodicity was left intact, deletions and duplications in the same region had only slight effects on nucleation activity. Deletions removing part or all of one of the nonrepetitive regions (that encoding the amino-terminal domain of the InaZ protein) did not abolish nucleation activity, but caused it to be limited to cooler threshold temperatures. In contrast, the non-repetitive carboxy-terminal domain of the InaZ protein was shown to be essential for ice nucleation at all temperatures. The differential requirements (for periodicity, and for the amino-terminus) in forming nuclei with different thresholds may be significant for understanding what determines the threshold temperature of an ice nucleus.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 50
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 215 (1988), S. 69-75 
    ISSN: 1617-4623
    Schlagwort(e): FhuA receptor protein ; Export ; Assembly ; Outer membrane ; Escherichia coli
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The FhuA protein (formerly TonA) is located in the outer membrane of Escherichia coli K12. Fusions between fhuA and phoA genes were constructed. They determined proteins containing a truncated but still active alkaline phosphatase of constant size and a variable FhuA portion which ranged from 11%–90% of the mature FhuA protein. The fusion sites were nearly randomly distributed along the FhuA protein. The FhuA segments directed the secretion of the truncated alkaline phosphatase across the cytoplasmic membrane. The fusion proteins were proteolytically degraded up to the size of alkaline phosphatase and no longer reacted with anti-FhuA antibodies. The fusion proteins were more stable in lon and pep mutants lacking cytoplasmic protease and peptidases, respectively. The larger fusion proteins above a molecular weight of 64000 dalton were predominantly found in the outer membrane fraction. They were degraded by trypsin when cells were converted to spheroplasts so that trypsin gained access to the periplasm. In contrast, FhuA protein in the outer membrane was largely resistant to trypsin. It is concluded that the larger FhuA‘-’PhoA fusion proteins were associated with, but not properly integrated into, the outer membrane.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 51
    Digitale Medien
    Digitale Medien
    Springer
    Molecular genetics and genomics 215 (1988), S. 161-164 
    ISSN: 1617-4623
    Schlagwort(e): Escherichia coli ; Ionising radiation ; Mutation ; DNA repair
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Escherichia coli K803 cells were mutagenized and screened for the presence of clones sensitive to ψ-rays but not to ultraviolet light. One new mutant of this type, named rorB, was isolated. This mutant is both cross-sensitive to mitomycin C and shows reduced conjugal recombination frequencies, but to a lesser extent than the phenotypically similar mutant recN. Unlike previously reported mutants of E. coli or yeast with an enhanced sensitivity to ionising radiations, rorB appears to be near wild type in ability to rejoin DNA double-strand breaks. The rorB gene maps close to ilvGEDAC at 84.5 min of the E. coli chromosome.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 52
    ISSN: 1573-5036
    Schlagwort(e): black gram ; boron deficiency ; borax rates ; green gram ; hollow heart ; hot-water-soluble boron ; kernel boron ; leaf boron ; peanut ; rice ; soybean ; sunflower ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The effect of boron (B) on peanut and soybean was examined in two omission and one B fertilizer rate trial on a Typic Tropaqualf in Northern Thailand. The B rate trial was combined with a comparison of the response of sunflower, green gram, black gram, wheat, and rice in addition to peanut and soybean grown in irrigated rice-based cropping sequences over two years. Omitting B induced the hollow heart symptom in 10% of peanut kernels with the incidence of hollow hearts closely related to B concentration in the kernels. Omission of B had no effect on the appearance of soybean seed or on the grain yield of either soybean or peanut. In the B rate experiment, omitting B depressed grain yield by 50% in sunflower and by 40% to 80% in black gram, induced B deficiency symptoms in green gram and the hollow heart symptom in peanut kernels, but had not significant effect on the grain yield of soybean, peanuts, rice, or wheat. B deficiency apparently depressed grain yield in black and green gram by delaying or inhibiting reproductive development thus reducing pod set.
    Materialart: Digitale Medien
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  • 53
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 39 (1988), S. 137-144 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; Hordeum vulgare ; barley ; boron toxicity ; variation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The growth and yield of seven wheat and two barley cultivars or lines, previously found to show different degrees of boron tolerance under field conditions, were compared in a pot experiment at a range of soil boron treatments. Soil treatments ranged up to 150 mg/kg applied B. Extractable B in soils ranged up to 103 mg/kg. At the highest B treatment seedling emergence was delayed, but the percentage emergence was not reduced. The degree of boron toxicity symptom expression varied between the wheat cultivars and lines, with the two most tolerant, Halberd and (Wq*KP)*WmH)/6/12, displaying the least symptoms. The concentration of boron applied to the soil which produced a significant depression of growth and yield varied between cultivars. For example, the yield of (Wq*KP)*WmH)/6/12 was not affected at the 100 mg/kg applied boron treatment, while the grain yield for (Wl*MMC)/W1/10 was significantly reduced at the 25 mg/kg treatment. There was a linear increase in boron concentration in tillers at the boot-stage with increasing concentration of boron in the soil. The most boron tolerant genotypes had the lowest tissue boron concentrations in each of the treatments. Halberd and (Wq*KP)*WmH)/6/12 had approximately half the boron concentrations of the more sensitive genotypes at the 25 and 50 mg/kg treatments. Differential tolerance of boron within the tissue was also observed. Both Stirling and (Wl*MMC)/W1/10 had significantly reduced total dry matter and grain yields at the 25 mg/kg treatment, while the concentrations of boron in boot stage tillers at this treatment were 118 and 100 mg/kg, respectively. On the other hand, Halberd and (Wq*KP)*WmH)/6/12 had tissue boron concentrations of 144 and 131 mg/kg, respectively, at the 50 mg/kg treatment but yield was unaffected. The relative responses in the pot experiment, for wheat, were in close agreement with field results. Halberd and (Wq*KP)*WmH)/6/12 had the highest grain yields, with the lowest concentrations of boron in the grain when grown under high boron conditions in the field. In pots these two genotypes proved to be the most tolerant of boron. For barley the advantage in grain yield in the field, expressed by WI-2584 compared with Stirling, was not repeated in pots. WI-2584 was, however, more tolerant than Stirling on the basis of total dry matter production. The results show that useful variation in boron tolerance exists among wheat, and that breeding should be able to provide cultivars tolerant to high levels of boron.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 54
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 110 (1988), S. 140-142 
    ISSN: 1573-5036
    Schlagwort(e): Gaeumannomyces graminis ; roots ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A root assessment tray was designed for the meticulous assessment of take-all on wheat seedling roots from soil bioassays. Subsequently, the detection of lateral root infections (in addition to the more obvious infections on main axes of seminal roots) resulted in increased estimates of propagule numbers of the take-all fungus (Gaeumannomyces graminis var.tritici) for 196 of the 368 soil samples bioassayed in a field study conducted in Western Australia between 1984 and 1986.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 55
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 105 (1988), S. 169-178 
    ISSN: 1573-5036
    Schlagwort(e): development ; fibrous root growth ; geotropism ; root deflection ; root model ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A model is described which simulates the growth of fibrous root systems. The root growth is specified in terms of growing time, numbers of axes, initiation times of axes, growth rates and branching characteristics of the roots, and characteristics governing the direction of root growth. The model generates a representation of the root system in which the locations of all branches and root tips are recorded in three-dimensional coordinates, and updates this representation in discrete time steps until the specified growing time is reached. Data are presented from a simulation of wheat root growth by the model. The simulated root system is represented pictorially and also graphically in the form of root length and root tip number profiles which are stratified by branching order class. The pictorial representations produced by the model are much more realistic than any which have been produced by past root growth models, and the graphical representations show trends in root length and root tip numbers which are the same as those commonly observed in real roots.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 56
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 109 (1988), S. 128-130 
    ISSN: 1573-5036
    Schlagwort(e): nitrogen ; root pruning ; shoot ; root ratio ; Thornley's model ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract In two experiments, wheat plants growing in solutions of different nitrogen concentration were subjected to root pruning. In higher concentrations of nitrogen the growth rate was higher, and the proportional allocation of growth to shoot higher, but pruning did not affect the allocation of growth at either level of nitrogen. This result gives no support to Thornley's source-sink model of the control of shoot: root ratio.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 57
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 109 (1988), S. 195-198 
    ISSN: 1573-5036
    Schlagwort(e): Anguina tritici ; Corynebacterium tritici ; disease complex ; inoculation methods ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Wheat,Triticum aestivum L. cv. Mexipak was artificially inoculated withAnguina tritici (Steinb.) under field conditions. Nematode inocula: 0, 0.1, 0.2 and 0.3 g of seed galls/50 seeds or, germinated seeds of wheat (sown in a 1-m long row) were either added as intact seed galls or as a suspension of 2nd stage juveniles. Inoculation of ungerminated seeds with juveniles produced the highest incidence of ear-cockle disease. Whereas, intact seed galls inocula produced the highest incidence of tundu disease. Ear-cockle incidence was always greater than that of tundu at all treatments. The highest reduction in grain yield was associated with the treatments that caused the highest incidence of tundu disease.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 58
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 112 (1988), S. 261-266 
    ISSN: 1573-5036
    Schlagwort(e): crown rot ; Fusarium graminearum ; interactions ; wheat ; zinc deficiency
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Wheat plants were grown at three levels of zinc nutrition in potted soil under controlled conditions. The surface soil in half of the pots was inoculated with a thin layer of milled chaff colonized byFusarium graminearum Group 1. Forty days after sowing, the plants were assessed for dry matter production and the extent of colonization by the pathogen. The concentration of zinc in the plant tissues was also determined. The zinc status of the plants ranged from severe deficiency through subclinical deficiency to sufficiency. The extent of colonization above the point of infection was decreased significantly by increasing the level of zinc supply. However, colonization of the seminal or secondary roots was not affected by zinc supply, nor was the incidence of infected plants. The unidirectional effect on resistance suggests that zinc has modified the contribution of the xylem flux to the upward spread of the pathogen.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 59
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 111 (1988), S. 171-175 
    ISSN: 1573-5036
    Schlagwort(e): hormones ; potassium status ; potassium transport ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 60
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 112 (1988), S. 45-52 
    ISSN: 1573-5036
    Schlagwort(e): barley ; boron toxicity ; genotypic variation ; mineral nutrition ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The mechanism of resistance toB toxicity in barley and wheat was studied in a solution culture experiment using several cultivars displaying a large range of sensitivity to excessB supply. Plants were cultured for 35 d atB concentrations ranging from normal to excessive (15 to 5000 μM, respectively) then examined for dry matter production and theB distribution between roots and shoots. In both species, increasedB supply was accompanied by increased tissueB concentrations, development ofB toxicity symptoms and depressed growth. At each level ofB supply, however, resistant cultivars accumulated considerably lessB than did sensitive cultivars, in both roots and shoots. Even at the lowestB supply, at which noB toxicity symptoms developed and growth was not affected, resistant cultivars maintained relatively low tissueB concentrations. No cultivar displayed an ability to tolerate high tissueB concentrations. These results indicate that sensitivity toB toxicity in barley and wheat is governed by the ability of cultivars to excludeB. If theB concentrations of tissues is used to indicate resistance toB toxicity, then cultivars have the same ranking whether cultured at a normal or excessB supply.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 61
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 110 (1988), S. 101-109 
    ISSN: 1573-5036
    Schlagwort(e): bean ; influx rate ; onion ; phosphorus efficiency ; rape ; ratio ; root-shoot ; ryegrass ; spinach ; tomato ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Plant species differ in their P efficiency,i.e. the P content in soil needed to reach their maximum yield. The differences in external P requirements can be atributed to either a lower internal P requirement for optimum growth or higher uptake efficiency of the plant. The objective of this research was to investigate the reasons for different P efficiencies of seven plant species. Onion, ryerass, wheat, rape, spinach, tomato and bean were grown in a P-deficient subsoil fertilized with 0, 2, 5, 10, 20, 40 and 80 mg P 100 g−1. All species showed a strong yield increase due to P fertilization. To reach 80% of maximum yield onion and tomato needed 17 and 11 mg P 100 g−1 respectively, corresponding to a soil solution concentrations of 6.9 and 5.7 μmol P l−1, whereas ryegrass, wheat and rape needed about 5 mg P 100g−1 corresponding to only 1.4 μmol P l−1 in soil solution. These differences in external P requirement cannot be explained by differences in their internal P requirement since onion, with the highest external P requirement, only contained 0.14% P in the shoot at 80% of maximum yield, while wheat, as the most P efficient species, contained 0.28%. P efficiency was related to the uptake efficiency of the plant which is determined by both root-shoot ratio and absorption rate per unit of root (influx). Species of low efficiency such as onion, tomato and bean had low influx rates and low root-shoot ratios, whereas species of medium to high efficiency had either high influx rates (rape and spinach) or high root-shoot ratios (ryegrass and wheat). The combination of both high influx rate and high root-shoot ratio was not found in any of the species studied.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 62
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 111 (1988), S. 25-35 
    ISSN: 1573-5036
    Schlagwort(e): carbohydrate accumulation ; chloride ; salinity-phosphorus interaction ; sodium ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Foliar inorganic ion and carbohydrate concentrations were determined in wheat plants treated with factorial combinations of phosphorus fertilizer and NaCl in a glasshouse experiment. Growth reductions and visual symptoms of salt toxicity were minimized when phosphorus nutrition was adequate, and were intensified by phosphorus deficiency. Foliar sodium and chloride accumulated up to 4.0–5.5% d.w. with salinity treatment. However, ionic concentrations within corresponding leaves or distributions between leaves of plants with different phosphorus treatments were not influenced by phosphorus treatment and had no relationship to the severity of salt toxicity symptoms. This suggests that phosphorus deficiency reduced the cellular tolerance for ion accumulation. A combination of phosphorus deficiency and salinity induced an accumulation of foliar starch and sucrose despite substantial reductions in net CO2 assimilation rates. This accumulation did not occur if phosphorus nutrition was adequate, which is consistent with the roles of phosphorus in carbohydrate metabolism. It is proposed that adequate phosphorus nutrition is essential for effective ion compartmentation by contributing to efficient carbohydrate utilization in salt-stressed wheat.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 63
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 107 (1988), S. 19-23 
    ISSN: 1573-5036
    Schlagwort(e): Gaeumannomyces graminis ; pectolytic enzymes ; Phialophora graminicola ; Phialophora sp. ; virulence ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Gaeumannmyces graminis var.tritici (Ggt), Phialophora sp. (lobed hyphopodia) andPhialophora graminicola vere grown in a liquid medium with pectin and on autoclaved wheat roots (root media) and the activity of pectolytic enzymes in culture filtrates was measured. Most strains of the fungi exhibited polygalacturonate trans-eliminase activity but no pectin methylesterase activity was detected.Ggt polygalacturonase was found in culture filtrates from all the media used whilePhialophora sp. did not exhibit activity of this enzyme in the unbuffered root media. No polygalacturonase activity was demonstrated forP. graminicola. A correlation was found (r=0.548) betweenin vitro polygalacturonase activity and the pathogenicity ofGgt to wheat seedlings.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 64
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 107 (1988), S. 137-143 
    ISSN: 1573-5036
    Schlagwort(e): mineral composition ; short-term flooding ; sodic soil ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract In sodic soils of the Indo-Gangetic alluvial plains of Northern India, flooding for short periods often occurs during the growing season of wheat, leading to low yields. A field study was therefore conducted to evaluate the effects of short-term flooding on growth, yield and mineral composition of wheat (Triticum aestivum Linn. emend. Fiori and Paol) in a sodic soil (pH 8.9, exchangeable sodium percentage 25). Flooding wheat for 2,4 and 6 days at the time of first irrigation (25-day old plants), significantly reduced tillering, plant height, delayed head emergence and resulted in 17.6, 29.0 and 46.7% reduction in grain yield, respectively, Flooding decreased oxygen diffusion rate (ODR) values, restricted root grwoth and reduced ion uptake, especially of N, P, K, Ca, Mg and Zn and led to higher absorption of Na, Fe and Mn. Under the conditions of this experiment, the reduced growth and yield of wheat resulting from short-term flooding was not due to Mn, Fe and Na toxicity but may be due to reduced uptake of nutrients resulting from O2 deficiency in the soil.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 65
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 12 (1988), S. 97-110 
    ISSN: 1573-5044
    Schlagwort(e): wheat ; somatic embryogenesis ; embryogenic callus ; 3,6-dichloro-o-anisic acid ; 2,4-dichlorophenoxyacetic acid ; 6-furfurylaminopurine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Nine experiments were conducted to determine effects of various culture medium addenda on induction of embryogenic calli from immature embryos of a responsiveTriticum aestivum L. genotype (PCYT 10). Effects were quatified by counting somatic embryos (embryoids) per callus. Optimal auxin concentrations to induce and maintain somatic embryogenesis were 3.62 μM 2,4-dichlorophenoxyacetic acid (2,4-D) or 9.05 μM 3,6-dichloro-o-anisic acid (dicamba). In general, dicamba permitted formation of significantly more embryoids than 2,4-D. Kinetin (6-furfurylaminopurine) at 2.56 μM or 4.65 μM significantly increased percentage scutellar callus when added to 2,4-D or dicamba-containing medium, respectively. Kinetin at 4.65 μM signficantly increased the numbers of embryoids formed when added to medium containing either synthetic auxin. Significantly fewer embryoids formed when cultures were incubated under diffuse light (16-h photoperiod). Casein hydrolysate (200 mgl-1) or L-arginine (0.23 mM) had no effect on numbers of embryoids formed, whereas L-tryptophan (0.20 mM) enhanced such formation with 2,4-D and decreased such formation with dicamba. Two additional experiments generally demonstrated that response to auxin source in the genotypes ND 7532, PCYT 20, Yaqui 50, and Oasis was similar to that in PCYT 10. The higher molar concentration of dicamba required to induce embryogenic callus coupled with more evident embryoid precocious germination and a more rapid rate of tissue necrosis upon extended incubation without subculture suggests that dicamba is metabolized more rapidly than 2,4-D inT. aestivum callus cultures.
    Materialart: Digitale Medien
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  • 66
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 12 (1988), S. 299-304 
    ISSN: 1573-5044
    Schlagwort(e): callus ; plant regeneration ; isozymes ; wheat ; barley
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Callus cultures fron non-organogenic, young and one-year old, and morphogenic calli were used to assess the value of isozymes analysis for the prediction of morphogenic capacity by studying esterase, peroxidase and acid phosphatase. Basic isozyme patterns of each enzyme for the callus were retained in all the callus stages and in the callus which has differentiated into shoots. With the development of shoot and/or root some conspicuous isozymes appeared for esterase and acid phosphatase and some disappeared for peroxidase. As the isozyme changes became apparent only after shoot or root initiation these enzymes could not be used as markers to distinguish between morphogenic and non-morphogenic calli.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 67
    Digitale Medien
    Digitale Medien
    Springer
    Journal of bioenergetics and biomembranes 20 (1988), S. 41-58 
    ISSN: 1573-6881
    Schlagwort(e): F1-ATPase ; H+-ATPase ; Escherichia coli ; uni-site catalysis ; unc operon ; chemical modification ; ATP synthase ; ATP
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie , Physik
    Notizen: Abstract We have reviewed recent molecular biological studies on F1-ATPase ofEscherichia coli and emphasized the advantages of using the bacterium in studies on this important enzyme. All subunits had homologies of varied degrees with those from other organisms. Mutations of F1 subunits caused defects in catalysis and assembly. Defects of the mutant enzymes were studied extensively together with the determination of the amino acid substitutions. Extensive molecular biological studies may help greatly in understanding the normal mechanism and assembly of the complex.
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  • 68
    Digitale Medien
    Digitale Medien
    Springer
    Nutrient cycling in agroecosystems 15 (1988), S. 123-136 
    ISSN: 1573-0867
    Schlagwort(e): corn ; soybean ; wheat ; maximum yield ; optimum yield ; Bray P1 ; exchangeable K
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Data from 32 years of a rotation-fertility experiment were analyzed to determine the average P and K application rates required for maximum yield and for optimum yield. A four-year rotation of corn, soybean, wheat, hay was used for the first 10 years and then changed to corn-1, soybean, wheat, corn-2. Rates of P application per 4-year rotation ranged from 0 to 196 kg ha−1 and for K from 0 to 558 kg ha−1. Multiple regression equations were fitted to the mean yields per 4-year rotation for the response of each crop to P and K applications. The range in P application rates in kg of P per 4-year rotation required to get maximum yields of corn was 118 to 172, for soybeans was 134 to 150, and for wheat was 116 to 138. The range in K application rates in kg K per 4-year rotation to get maximum yields of corn was 378 to 411, for soybeans was 324 and 476, and for wheat was 11 to 323. For rates of application where P and K added exceeded crop removals, soil test P and K increased linearly with the cumulative positive balance of P and K. Where crop removal exceeded application rate, no relation was found between crop removal and soil test.
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  • 69
    Digitale Medien
    Digitale Medien
    Springer
    Antonie van Leeuwenhoek 54 (1988), S. 285-299 
    ISSN: 1572-9699
    Schlagwort(e): fimbriae biogenesis ; genetic organization ; gene clusters ; protein translocation ; Escherichia coli ; adhesion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The genetic organization of the determinants of type 1, K88ab, K99 fimbriae and P(pap)pili of Escherichia coli is presented. The functions of the various gene products are described and a model for the process of fimbriae biogenesis is presented and discussed.
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  • 70
    ISSN: 1572-9699
    Schlagwort(e): Escherichia coli ; urinary tract infection ; dogs ; fimbriae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A number of Escherichia coli strains have been isolated from dogs with urinary tract infections. These strains have been characterised with respect to their O, K, H, and fimbrial antigens, colicin production, antibiotic resistance, plasmid content and their ability to haemagglutinate erythrocytes from various species. Crossed immunoelectrophoresis of fimbrial extracts, as well as the reaction of partly purified fimbriae of a number of these strains with monoclonal antibodies revealed homology or a strong crossereaction with an F12 fimbrial subunit protein of human uropathogenic E. coli strains. Unlike human F12 fimbriae producing strains, the dog isolates did agglutinate dog erythrocytes in the presence of D-mannose but not human erythrocytes, indicating that the adhesin carried by these strains is different from the adhesin on fimbriae of human uropathogenic E. coli. Similar indications were obtained from experiments with latex beads coated with the receptor for P-fimbriae. These beads were agglutinated by Escherichia coli strains from human urinary tract infections, but not by the dog isolates described here. Preliminary adhesion experiments of human and dog Escherichia coli to human bladder epithelial and canine kidney epithelial cells also showed differences in adhesion depending on the origin of the strain tested.
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  • 71
    Digitale Medien
    Digitale Medien
    Springer
    Plant growth regulation 7 (1988), S. 3-17 
    ISSN: 1573-5087
    Schlagwort(e): Abscisic acid (ABA) content ; barley ; genetic variation ; grain weight ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Two genetically related wheat lines growing in cabinets were given different temperatures during grain filling, and abscisic acid (ABA) was measured in whole grains by gas chromatography with an electron-capture detector. Three genetically related barley lines grown in the field were assayed for ABA content in endosperm and embryo fractions separately by radiommunoassay. Maximum grain growth rate and final weight per grain of the two wheat lines differed by 50–60% at low temperature and 30–40% at high temperature. During grain development two peaks in ABA level were observed at low temperature but only one at high temperature. At times when differences in grain growth rate between genotypes and between temperature treatments were large, the corresponding differences in ABA concentration were small. In barley, one line (Iabo 14) had 30% heavier grains than the other two (Onice and Opale). Endosperm ABA concentrations showed no clear differences between genotypes until grain filling was nearly complete. Embryo ABA levels were up to 10-times greater than those in the endosperm, with Opale having significantly less ABA in the embryo than the other two cultivars. Our experiments did not provide evidence for a causal relationship between ABA levels during grain filling and grain growth rate or final weight.
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  • 72
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 38 (1988), S. 93-100 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; breeding ; preharvest sprouting ; heritability ; variation ; α-amylase ; falling number
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Preharvest sprouting resistance is a major breeding criterion in many regions where white wheat (Triticum aestivum L.) is produced. Availability of genetic sources of sprouting resistance should significantly advance this goal. Objectives of the present investigation were to determine heritabilities and genetic variation of sprouting resistance in progeny of six susceptible genotypes and Clark's Cream, a cultivar with excellent sprouting resistance. Sixty-five randomly selected F2:F3 lines from the six parental combinations were evaluated in blocks-within-replication designs at two locations during 1984–85. Falling number, α-amylase activity, and sprouting percentage in simulated rain were usually more favorable in F2:F4 grain than in grain of the susceptible parents and frequently equalled levels in grain of the resistant parent. Broad sense heritability estimates were moderate to high for falling number and α-amylase activity, low to moderate for visual sprouting, and inconsistent for embryo germination in ABA. Phenotypic correlations with sprouting were significant most often for falling number and least often for the agronomic traits, days to heading and kernel weight. We concluded that increased preharvest sprouting resistance is an attainable objective when genetic sources of strong resistance and appropriate selection criteria, such as sprouting after simulated rain, are used.
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  • 73
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 39 (1988), S. 161-166 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; dormancy ; gibberellic acid ; pre-harvest sprouting
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Gibberellic acid, cold (4°C) and a combination of these two treatments were tested for use in breaking dormancy in 27 lines of white-grained wheat with varying levels of resistance to pre-harvest sprouting. Germination increased in all lines treated with gibberellic acid. Dormancy could be broken with 1 μM gibberellic acid. Response to cold varied. A combination of gibberellic acid and cold treatment was the most effective. This technique has been found useful in treating seed in a breeding program aimed at producing wheats with resistance to pre-harvest sprouting.
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  • 74
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 39 (1988), S. 7-25 
    ISSN: 1573-5060
    Schlagwort(e): Hordeum vulgare ; barley ; Triticum aestivum ; wheat ; cytogenetics ; chromosome identification ; gene localisation ; interspecific gene transfer ; chromosome elimination
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Achievements and limitations regarding three aspects of cytogenetic research in barley and common wheat are illustrated and discussed. Unambiguous chromosome identification has become possible through the application of chromosome banding techniques, mainly C-banding, N-banding and Ag-banding. Gene localisation studies have yielded a vast amount of information regarding the genetic architecture of barley and wheat. Many genes have been allocated to specific chromosomes, and linkage studies have been carried out with some of these genes. There is growing evidence for a considerable discrepancy between distances on the genetic linkage maps and the physical maps of barley and wheat chromosomes. Although barley can be hybridised with most species of the genus Hordeum and with several species of related genera, interspecific gene transfer is very rare and barley breeding can presently make use of the gene pool of only one wild species, viz. H. vulgare ssp. spontaneum. For wheat breeding, the gene pools of species of the genus Triticum and species of related genera are accessible. Several methods have been developed to achieve gene transfer. Genome interactions in interspecific hybrids result in spatial separation of the parental genomes, in nucleolar competition, and sometimes in chromosome elimination and the formation of haploids.
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  • 75
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 38 (1988), S. 85-92 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; preharvest sprouting ; dormancy ; α-amylase ; falling number ; inhibitors ; embryo response
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Resistance to preharvest sprouting has been observed in several white wheat (Triticum aestivum L.) genotypes, but the mode of resistance has not been determined. Studies were conducted to characterize the strong preharvest sprouting resistance in Clark's Cream genotype to facilitate breeding for the trait. Clark's Cream and five other hard red and white wheat genotypes were grown in the glasshouse and field and effects of simulated rain, embryo maturity, inhibitors in floral parts and GA, endogenous inhibitors, and ABA and GA combinations on sprouting were measured. The six genotypes differed significantly in sprouting after simulated rain, α-amylase activity, and response to GA and ABA. Embryo maturity and inhibition levels in floral parts and caryopses were nearly similar for all genotypes. Clark's Cream appeared to differ most in high embryo sensitivity, which was fairly nonspecific for ABA, GA, and endogenous inhibitor, and in low α-amylase production during sprouting. Breeding procedures that lead to the preharvest sprouting resistance of Clark's Cream are discussed.
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  • 76
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 38 (1988), S. 105-111 
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; tillering ; heritability ; gene effects ; epistasis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Effective utilization of uniculm wheat (Triticum aestivum L.) germplasm in breeding programs requires an understanding of the inheritance of the uniculm character. The parents, F1, F2, and first generation backcrosses (B1 and B2) of two crosses, each utilizing a uniculm spring wheat line and a locally adapted winter wheat cultivar, were space planted in an experiment to acquire information regarding the genetic control of culm number. Significant F1 deviations from midparent values revealed the presence of substantial non-additive gene effects. The scaling tests of Mather and the joint scaling test detected the presence of epistasis. Hayman's six-parameter model revealed that a negative dominance effect provided the major contribution to variation in culm number, while additive x additive and dominance x dominance gene effects were of considerable importance.
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  • 77
    ISSN: 1573-5060
    Schlagwort(e): Triticum aestivum ; wheat ; grain yield ; selection ; simple mass selection ; gridded mass selection ; rhombic grid selection
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary An experiment was conducted in Winnipeg, Manitoba, Canada to: (1) ascertain the efficiency of gridded mass selection; (2) to determine if additional selection efficiency can be achieved through refinement of the gridded mass selection procedure; and (3) to determine if the degree of homozygosity has an effect on response to single-plant selection. Three selection methods [simple mass selection (SMS); gridded mass selection (GMS); and a new rhombic grid selection (RGS)] were applied to four populations [a conventional F2 (CON-F2); an intermated F2 (INT-F2); and 2 partial backcrossed populations] developed from a biparental cross involving the Canadian spring wheat cultivars, ‘Glenlea’ and ‘Sinton’. Averaged over the 4 populations, a single cycle of RGS (10% selection intensity) increased yield by about 9.5%, whereas GMS and SMS increased yield by approximately 4.5% and 3.1%, respectively. The degree of homozygosity of individual plants that make up the population appeared to have an effect on the efficiency of selection. In general, selection was more efficient in the two partial backcrossed populations, and least efficient in the CON-F2 and INT-F2 populations. The largest response to selection (15.9%) was attained when RGS was applied in the backcross to Glenlea population, and the lowest response (1.2%) when SMS was enforced in the CON-F2 population. This paper represents the first report on the efficiency of rhombic grid selection for yield improvement in cereal crops.
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  • 78
    ISSN: 1573-5036
    Schlagwort(e): Gaeumannomyces graminis var.tritici ; rye grass ; Trichoderma hamatum ; T. harzianum ; T. koningii ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Trichoderma hamatum, T. harzianum andT. koningii were isolated from wheat and rye-grass roots from a field in Western Australia. Frequency of occurrence ofTrichoderma spp. was higher on roots subjected to washing only, for both wheat and rye-grass than the roots which were surface-sterilized with 0.6% or 1.25% NaOCl.Trichoderma spp. were recovered at a higher frequency on PDA amended with lactic acid (pH 4.5) than on PDA alone (pH 5.6) or PDA with streptomycin. In general,Trichoderma spp. were isolated at a higher frequency from roots of wheat than that of rye-grass.T. hamatum occurred at a higher frequency in rye-grass roots than in wheat, whereasT. harzianum was more common in roots of wheat than in rye-grass, especially in seedling and milky ripe stages.T. koningii was recovered at a higher frequency from roots at seedling stage of rye-grass than wheat, the reverse being true at tillering stage.T. koningii was not recovered from roots of either host in any sampling when they were surface sterilized with 1.25% NaOCl. The take-all fungus was isolated from wheat and rye-grass roots more frequently at tillering and stem extension stages than others. It was severely pathogenic to both hosts in sterilized and non-sterilized soil. Addition of lactic acid, HCl or streptomycin to PDA did not affect the growth of theTrichoderma spp. tested, but the growth was slower on Martin's medium than on other media. In generalT. harzianum andT. koningii grow faster thanT. hamatum. The growth of the three species were not different at 20 and 25°C, but at 15°c growing of all species was significantly reduced. Incorporation of lactic acid into PDA prevented the bacterial growth in all treatments. Streptomycin too reduced but to a lesser degree than lactic acid. Surface sterilization with NaOCl decreased the recovery of both bacteria and fungi. T. hamatum andT. koningii reduced the mortality of wheat and rye-grass plants inoculated with the take-all fungus in sterilized and non-sterilized soil, whereT. harzianum did not protect wheat or rye-grass from infection by the take-all fungus.
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  • 79
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 109 (1988), S. 263-269 
    ISSN: 1573-5036
    Schlagwort(e): peas ; plant genetics ; plant growth ; Pseudomonas ; rhizosphere bacteria ; Serratia ; symptoms ; wheat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Spring wheat (Triticum aestivum L.) and pea (Pisum spp.) genotypes were tested for reaction to root inoculation with rhizosphere bacteria affecting plant growth. Plant response was studied in greenhouse experiments after treatment of seedlings with bacteria suspended in nutrient broth. Significant genotype variation was found in both wheat and pea in terms of shoot dry weight and severity of bacteria-induced leaf symptoms. For most bacterial isolates tested, there was good correlation between ratings of leaf symptoms 7 to 14 days after inoculation and growth inhibition measured after four weeks. Interactions between isolates and plant genotypes were significant in both wheat and pea (P=0.0024 and 0.0001, respectively), but genotypes with sensitivity or tolerance to most isolates could be distinguished. In an outdoor pot experiment, two of the bacterial isolates caused delayed plant development and differential decreases in grain yield of wheat genotypes. The hypothesis that the reaction of wheat genotypes to the tested becteria was related to their influence on bacterial establishment in the rhizosphere could not be substantiated.
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  • 80
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 21-24 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Sample concentration ; Chromatographic evaporation ; Solvent effect
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Several micro-techniques for the removal of solvent from dilute solutions of volatile compounds have been compared. Large solute losses were experienced when the conventional blow-down technique was applied. Better yields could be obtained with static evaporation procedures, as long as an effective reflux was maintained. However, careful optimization of the vessel design and operating conditions is necessary. The most efficient volume reduction technique was shown to be chromatographic evaporation. Quantitative recoveries were obtained for the compounds tested and the process was significantly faster than static concentration. Moreover, operating conditions (gas flow, temperature) are less critical. With modifications, the principle can be used for the concentration of large sample volumes down to a few microliters.
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  • 81
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Stationary phase polarity ; Polarity parameters ; Structure-retention relationships
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The new stationary phase polarity parameters BN and BS evaluated from the concept of the electric intermolecular interactions are used to describe the polarity of polyoxyethylene glycol dialkyl ethers and their sulphur analogs. Relations between the discussed parameters and accepted measures of surfactants' polarity are presented and discussed. The considered parameters are correlated with the compound structures. Structural increments for characteristic fragments of the molecule are calculated and use to predict BN and BS values.
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  • 82
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 134-138 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Sulfur ; n-Octane adsorption
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary From the adsorption isotherms of n-octane on the surface of sulfur at 29.8°C and 40.6°C some thermodynamic functions were determined. On the basis of these data the structure of the adsorbed layer of n-octane is postulated. The molecular interactions and adsorption mechanism are also discussed. It is stated that both quasi-liquid and quasi-sold layers may be formed on the surface of sulfur depending on the surface coverage with n-octane.
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  • 83
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 313-318 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Retention index ; Slope of log plot ; Homologous series ; Partition coefficient
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The slope of the n-alkane log plot dt′R/dnc (t′R=adjusted retention time; nc=carbon number) for a stationary phase can be used to obtain the retention index of an unidentified substance in a chromatogram containing only one peak with a known retention index, or to predict the retention time of a substance from that of a different homolog in the same series. It can also be used to translate retention indices into relative retention time, partition coefficient or specific retention volume. Published values of the slope are collected and critically evaluated. Equations are deduced that predict its approximate value at a specified temperature given the value at only one other temperature.
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  • 84
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 393-396 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Separation of optical isomers ; Chirasil-Val capillary columns ; Amino acid esters
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary D,L-amino acids were derivatized with (+), (±)-2-butanol or N-trifluoroacetyl-L-prolyl chloride (L-TPC) and then chromatographed. Four optical isomers were separated on a Chirasil-Val capillary column. By this method, the concentration of optical impurities arising from the commercial optically active reagents can be determined. The observed abnormal elution orders of enantiomeric amino acid esters may be caused by a selective intermolecular force.
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  • 85
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Essential oils ; Evaporation rate ; Perfume composition
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A simple method was developed for the determination of the evaporation rate of essential oils and perfumery composition using gas chromatography with temperature programming. The volatility of 19 essential oils and 17 perfumery composition was evaluated. The method is useful for different comparative measurements.
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  • 86
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 598-602 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Capillary columns ; Steroid profiles
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Steroid conjugates are hydrolysed enzymatically using β-glucuronidase after extraction from urine using a solid phase extraction cartridge. After hydrolysis the free steroids are removed from the matrix, again utilising solid phase extraction. Derivatisation of the free hydroxyl groups using Hydrox-Sil AQ produces the respective TMS ethers which are extracted into hexane, in which solvent they are stable for many days. Capillary GC analysis with flame ionisation detection produces a profile of the steroids present in the sample. This technique is suitable for following changes in the urinary excretion profiles of patients undergoing investigation for a variety of steroid production-related diseases.
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  • 87
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 609-612 
    ISSN: 1612-1112
    Schlagwort(e): Column liquid chromatography ; Gas chromatography ; Triglyceride composition of grapes ; Identification system
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The triglyceride composition of the Tempranillo grape (Vitis vinifera) has been examined by a combination of HPLC and GLC. To identify the triglycerides, equations were applied relating log k′ with the molecular variables: equivalent carbon number, chain length and number of double bonds in each of the fatty acids in the glycerides. Ten triglycerides were found, the principal ones being trilinolein (35.75%), dilinoleyl-olein (21.03%) and dilinoleyl-palmitin (17.02%).
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  • 88
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 655-658 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Structure-retention relationships ; Connectivity indices, topological indices ; Alkenes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Retention indices of different alkenes are correlated with connectivity and topological parameters. The appropriate statistically valid relations hips are derived and discussed.
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  • 89
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 735-736 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; α,ω-diiodoperfluoroalkanes ; Separation ; identification
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The separation of α,ω-diiodoperfluoralkanes on a glass capillary column coated with OV-101 methylsilicone was investigated. Retention indices were determined at three temperatures (140, 150 and 160°C). The correlation between the retention indices and the boiling points of the investigated compounds was studied.
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  • 90
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 731-734 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Retention Index (l) ; Temperature dependence of Retention Index
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A linear dependence of (T−T1)/[1(T)−1(T1)] on temperature (considering the retention index 1(T1) at temperature T1 as a standard value) is derived. Both ther retention index at an assigned temperature and the temperature dependence of the retention index can be calculated from retention data measured at two temperature-programing rates.
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  • 91
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 26 (1988), S. 171-177 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; GC/MS analysis ; Polycyclic aromatic hydrocarbons ; Bituminous coal ; Brown coal ; Plant waxes ; Thermodesorption
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Polycyclic aromatic hydrocarbons (PAH) today are ubiquitous detectable constituents of recent sediments. The compounds are adsorbed on particulate emissions and are thus transferred to the environment. To date the analysis of PAH in sediments, dust samples and plant material is based mainly on the application of solvent-extraction methods followed by liquid chromatography and/or gas chromatographic separation of the extracts. An alternative approach for the analysis of PAH in solid samples such as coal, sediments, dust samples and plant waxes is shown in this contribution. A commercially available device for the analysis of volatile compounds present in solid matter is connected on-line to a GC/MS system. The device enables the thermal desorption of hydrocarbons at a temperature of 320°C. Subsequently, the hydrocarbons trapped on the initial part of the capillary column are analyzed by GC/MS. The application of mass chromatography provides the possibility of detection and quantitation of PAH in complex mixtures even when they coelute with other compounds. The sample amount required varies between 1 and 10 mg depending on the hydrocarbon content.
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  • 92
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 26 (1988), S. 229-233 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Glass capillaries ; Chirasil-Val ; Immobilisation ; Enantiomeric separation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Immobilisation methods of the chiral silicone stationary phase Chirasil-L-Val have been studied. In addition to the standard techniques of radical-induced immobilisation with dicumyl peroxide and azo tert-butane, immobilisation was solely achieved by thermal treatment: conditioning at low flow-rates or under stop-flow conditions led to unexpectedly high immobilisation despite mild temperatures. The presence of water vapor in the carrier gas accelerated the immobilisation process. While up to 75% immobilisation was attainable with both ATB and thermal methods, immobilisation with DCUP did not exceed 50%, despite relatively high DCUP concentrations. Whilst all immobilisation methods were accompanied by varying degrees of racemisation at the chiral centre, it was possible to establish conditions that yielded a high immobilisation (in excess of 70%) with a negligible loss in enantiomeric selctivity. The immobilisation reactions also slightly affected the polarity of the stationary phase, reflected in a shift of the Kovats-Indices of amino acid derivatives and in the accompanying “Squalane-Effect”. With respect to immobilisation, racemisation and polarity shift, thermal immobilisation with water-saturated carrier gas proved to be the optimum method.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 93
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; (S)-(+)-Naproxen ; Amino acid methyl esters ; Resolution of diasteroisomers
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A GC method has been elaborated for the separation of enantiomers of some amino acid methyl esters after derivatization with activated (S)-(+)-naproxen. Nine amino acid ester paris were completely resolvede in a single run on a fused silica capillary column.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 94
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 993-998 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; HPLC system ; Micropacked column ; Organic mobile phase ; UV detection
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Retention behaviours of aromatic hydrocarbons were examined by using the vapour of an organic substance as the mobile phase and silica gel as the stationary phase. Gas chromatographic separation of aromatic hydrocarbons was demonstrated by using a system comprising a liquid chromatographic (LC) pump, a micropacked column for LC, a column oven and a UV detector.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 95
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Retention index ; Hydrocarbons
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The retention of hydrocarbons present in the C5 pyrolysis fraction of gasolines on the stationary phases squalane and methylsilicone oil JXR at 30, 40 and 50°C was investigated by capillary gas chromatography. The unified retention indices of the hydrocarbons were also calculated on squalane. The retention indices obtained on these two phases were interrelated and the quantitative relationship with the structure of the solutes was studied. Equations based on the unified retention indices calculated on squalane and some selected structural elements of the solutes permit the calculation of their retention on methylsilicone with sufficient accuracy.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 96
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 589-592 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Hold-up time determination
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary New versions are suggested for the gas hold-up time calculation in gas chromatography. The results are compared with those obtained by using other methods. The advantages of the suggested ways of calculation are pointed out.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 97
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 621-626 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Pre-column photolysis ; Halogenated hydrocarbons ; Identification of photolysis products ; Reaction mechanisms
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Photodecomposition of chloro- and bromoderivatives of saturated, unsaturated and aromatic hydrocarbons has been studied under flow conditions using reaction gas chromatography. The photodegradation products were separated on a column coated with squalane and identified by comparing the measured retention data with those of standards and published retention indices, The results can be used to clarify the decomposition of such compounds.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 98
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 725-730 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Structure-retention correlation ; Kováts retention index ; Alkylaromatics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Relative retention data and Kováts retention indices were measured for several hydrocarbons (mainly for alkylbenzenes) on dinonylphtalate and polyethylenelycol 4000 stationary phase. Correlations were searched between these retention data and the following physical (boiling point, molrefraction, molvolume) and topological (connectiviity index and general index of molecular complexity) properties of solutes. The best fitting equations was choosen among more than 150 equations involving linear, quadratic, exponential, two variables linear and quadratic dependence of retention data and the properties mentioned as well as their inverses.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 99
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 25 (1988), S. 817-821 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Water analysis ; Macroreticular polymeric adsorbent resins ; Herbicides
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A method is described for the determination of 3-phenyl-4-hydroxy-6-chloropyridazine in potable water. The method is based on isolation and enrichment by passing the water sample through a column of macroreticular polymeric adsorbent resin, concentration, derivatisation with pentafluorobenzoyl chloride and GC measurement with a N-specific detector. The individual experiments for establishing the working conditions, especially the adsorption characteristics of different types of resin, are described. The highest enrichment efficiency is obtained with the methacrylate-type resin XAD7. In field-sampling experiments a 10cm column yields 57% recovery at 100mLmin−1 flow rate, 0.3 ppb concentration level and 1 L sample volume. The method is completely documented; performance data are a detection limit of 0.07 μg L−1 and a mean recovery of 75% at the 0.3 ppb level.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 100
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Liquid crystals ; Thermodynamic properties
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Thermodynamic properties of 22 solutes at infinite dilution have been determined in the smectic, nematic and isotropic mesophases of 4,4′-bis(heptyloxy)azoxybenzone. The thermodynamic properties are discussed in relation to the solute-solvent (liquid crystal) interactions as conditioned by the degree of order in the liquid crystal.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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