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  • 1
    Electronic Resource
    Electronic Resource
    Growth of bacteria at 100°C and beyond (1981)
    Springer
    Archives of microbiology 129 (1981), S. 127-128 
    Details
    ISSN: 1432-072X
    Keywords: Continuous culture ; Adaptation ; Simulation of hot springs ; Boiling point ; Caldoactive bacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Bacillus caldolyticus, a caldoactive bacterium originating from a hot spring at Yellowstone Park, was grown in a defined medium, whose composition resembled that of the pool water. Using a chemostat culture, which simulated the natural conditions, the organism could be adapted to grow at 100°C at a reasonable rate. Under increased pressure growth occurred also at 105° C.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00455347
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  • 2
    Electronic Resource
    Electronic Resource
    Properties of enzymes from bacteria grown in the 70–100°C range (1981)
    Springer
    Archives of microbiology 130 (1981), S. 159-164 
    Details
    ISSN: 1432-072X
    Keywords: Adaptation ; Boiling point ; Caldoactive enzymes ; Stabilization ; Thermostability ; Thermal characteristics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In chemostat cultures of Bacillus caldolyticus, adaptation in a single step from 70–100°C was followed under aerobic and oxygen-limited conditions and was found to proceed more smoothly under the latter circumstances. Variations of the medium (e.g. yeast extract or silicate concentrations) showed that growth at 100°C is in all respects similar to that of cultures at moderate temperatures. Enzyme preparations derived from cultures at 5°C intervals between 70 and 100°C were used to determine the temperature range. For all nine enzymes tested, the optimum temperature was found to be 67°C; the latter was independent of the growth temperature. Differences were found, however, with respect to the maximum temperature of individual enzymes, and three groups, with maxima between 70 and 80°C, 80 and 90°C and 90 and 100°C can be distinguished. Again, there was no correlation with the growth temperature. Stability experiments also revealed that enzymes from the same organism can have different thermal properties: Some were found to be quite thermolabile (e.g. the pyruvate kinase), while others (e.g. hexokinase and glutamate-pyruvate transaminase) exhibited a high thermostability. These properties were not related to the growth temperature within the 70–100°C range, too. Six of the enzymes tested could be stabilized by their respective substrates, but the degree of protection varied for individual enzymes. Three enzymes (acetate kinase, glutamate dehydrogenase and myokinase) could not be stabilized by their substrates. Comparative experiments with the hexokinase suggested, that the thermal integrity of the enzymes is better protected within the cell as compared to the stability of the enzyme preparations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00411071
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  • 3
    Electronic Resource
    Electronic Resource
    Effects of sodium chloride on the plasma membrane of halotolerant Dunaliella primolecta: an electron spin resonance study (1982)
    Springer
    Archives of microbiology 131 (1982), S. 184-190 
    Details
    ISSN: 1432-072X
    Keywords: Dunaliella primolecta ; Malotolerant ; Adaptation ; Plasma membrane ; ESR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Electron spin resonance spectroscopy was used to monitor the in vivo microviscosity of the plasma membrane and lipid extracts of the salt tolerant alga, Dunaliella primolecta. The fluidity of the plasma membrane decreased as the algae were adapted to and suspended in higher sodium chloride concentrations [2–24% (w/v)]. Both biochemical modification and a physical interaction between Na+ and lipids were implicated. When the microviscosity of the plasma membrane and that of lipid extracts were determined as a function of temperature, two or three lipid phase transformations were observed. There were always transformations at 9–14° C and 39–43° C. These were interpreted as the onset and completion of the lipid phase transition of at least a major lipid component of the membrane, possibly the entire membrane. These transformation temperatures were independent of the salt concentration to which the algae were adapted or suspended. This suggests that D. primolecta exists with some of its membrane in the solid-fluid mixed lipid state. With a NaCl concentration of 8% (w/v) or greater in the growth medium, a third transformation occurred around 20–22° C. It was the result of a lipid-lipid interaction and was not related to adaptation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00405876
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  • 4
    Electronic Resource
    Electronic Resource
    Ultra-violet mutagenesis of Synechocystis sp. 6701: mutations in chromatic adaptation and phycobilisome assembly (1984)
    Springer
    Archives of microbiology 138 (1984), S. 237-243 
    Details
    ISSN: 1432-072X
    Keywords: Cyanobacteria ; Synechocystis 6701 ; Phycobilisomes ; Ultra-violet ; Mutagenesis ; Assembly ; Chromatic ; Adaptation ; Rods ; Cores
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Mutations affecting pigmentation of the cyanobacterium Synechocystis sp. 6701 were induced with ultraviolet light. Two mutants with phycobilisome structural changes were selected for structural studies. One mutant, UV08, was defective in chromatic adaptation and incorporated phycoerythrin into phycobilisomes in white or red light at a level typical of growth in green light. The other mutant, UV16, was defective in phycobilisome assembly: little phycocyanin was made and none was attached to the phycobilisome cores. The cores were completely free of any rod substructures and contained the major core peptides plus the 27,000 Mr linker peptide that attaches rods to the core. Micrographs of the core particles established their structural details. Phycoerythrin in UV 16 was assembled into rod structures that were not associated with core material or phycocyanin. The 30,500 Mr and 31,500 Mr linker peptides were present in the phycoerythrin rods with the 30,500 Mr protein as the major component. Phycobilisome assembly in vivo is discussed in light of this unusual mutant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00402128
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  • 5
    Electronic Resource
    Electronic Resource
    Photosensory transduction in the flagellated alga, Euglena gracilis (1983)
    Springer
    Archives of microbiology 134 (1983), S. 204-207 
    Details
    ISSN: 1432-072X
    Keywords: Photosensory ; Cations ; pH ; Flagellated ; Algae ; Adaptation ; Euglena gracilis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Euglena were cultured under 3 W m-2 constant white light. In culture medium, cells show immediate and long lasting step-down photophobic responses and photoaccumulation behavior to blue light if dim red light-adapted for 30 min. However, if cells are suspended in buffered, saltcontaining solutions (adaptation buffers), strong step-down photobehavior and photoaccumulation responses are not observed for several hours. These behaviors gradually increase in strength to reach a maximum after 6–12 h; after which a stable response is maintained. The relative rates of appearance and the relative strengths of the responses are influenced by the concentrations of Ca2+ and K+, but not H+ or Na+ ions, in the adaptation buffers. Expression of the stepdown photobehavior thus requires that the cells adapt to the chemical environment in which they are suspended.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00407758
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  • 6
    Electronic Resource
    Electronic Resource
    Theoretical considerations on growth kinetics and physiological adaptation of nutrient-limited phytoplankton (1984)
    Springer
    Archives of microbiology 140 (1984), S. 96-100 
    Details
    ISSN: 1432-072X
    Keywords: Physiology ; Adaptation ; Growth ; Droop ; Monod
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In many experimental ecological studies on phytoplankton species the growth response of an organism to the prevailing environmental conditions have been studied. Curves relating specific growth rate (μ) to the external nutrient concentration (S) have been constructed to compare nutrient-limited growth of different species under steady state conditions. Microorganisms adapt their physiology to a certain limitation in order to optimize growth. Therefore the shape of the μ/S curve is closely related to the way a micoorganism adapts its physiology. To see how physiological adaptation and growth rate are interconnected to each other, both can be related to the internal concentration of the growth-limiting nutrient. How the growth rate is related to the internal nutrient concentration is presented in a mathematical equation. Many phytoplankton species during growth under different nutrient limitations show a linear relationship between μ and the reciprocal value of the internal nutrient content (= Yield). This was originally observed by Droop. The model presented here gives a theoretical explanation of this phenomenon.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00409779
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  • 7
    Electronic Resource
    Electronic Resource
    Can strains give adequate information for adaptive bone remodeling? (1984)
    Springer
    Calcified tissue international 36 (1984), S. S118 
    Details
    ISSN: 1432-0827
    Keywords: Bone ; Strain ; Remodeling ; Adaptation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary For bone to remodel adaptively, the cells responsible should follow some algorithm. Nine different loading situations and structures are discussed. It seems that either algorithm must be extremely complex, or cells in different structures must follow different algorithms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02406144
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  • 8
    Electronic Resource
    Electronic Resource
    The correlation of the receptor potential with the light induced transient increase in intracellular calcium-concentration measured by absorption change of arsenazo III injected into Limulus ventral nerve photoreceptor cell (1980)
    Springer
    European biophysics journal 6 (1980), S. 191-208 
    Details
    ISSN: 1432-1017
    Keywords: Receptor potential ; Intracellular and extracellular calcium concentration ; Intensity dependence ; Adaptation ; Sensitivity control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract The light-induced membrane voltage response (receptor potential, ReP) and the absorption change of the intracellularly injected calcium indicator arsenazo III (arsenazo response) were recorded simultaneously in Limulus ventral nerve photoreceptor cells. A double pulse technique was applied for stimulation. After pressure injection of the indicator into the cell absorption changes were measured at 646 nm to obtain a measure of the changes of the intracellular calcium ion concentration. 1. The size of the arsenazo response increases with increasing intensity of the light stimulus. The intensity dependence of the size of the arsenazo response δAmax shows almost no correlate with the peak amplitude of the ReP, but correlates rather well with the time integral of the ReP. 2. Decreasing light adaptation (caused by prolongation of the repetition time of the pulse pairs) leads to an increase in size of the arsenazo response. Also here δAmax correlates better with the time integral of the ReP than with its peak amplitude. 3. Lowering the calcium concentration in the superfusate (from 10 mmol/l to ca. 40 Μmol/l) causes after ca. 10 min a drastical diminution of the arsenazo response to values below the noise level, and a less marked reduction in size of the ReP. The falling phase of the ReP is slower. After return to normal calcium concentration the arsenazo response recovers partly in ca. 50 min, while the ReP recovers faster. The results show two opposite correlations between ReP and arsenazo response: Increase in size and duration of the ReP causes a greater transient increase of the intracellular calcium ion concentration. This in turn tends to reduce and shorten the ReP. Which effect dominates obviously depends on the conditions of the experiment: when the calcium concentration in the superfusate is reduced to ca. 40 Μmol/l a slow decrease of the ReP is accompanied by a small increase of the intracellular calcium ion concentration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00537293
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  • 9
    Electronic Resource
    Electronic Resource
    Adaptation properties of the ERG in the grasshopper, Romalea microptera (1981)
    Springer
    European biophysics journal 7 (1981), S. 205-208 
    Details
    ISSN: 1432-1017
    Keywords: Grasshopper ; Electroretinogram ; Adaptation ; Spectral sensitivity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract The grasshopper ERG displays a rapid recovery of responsivity following the onset of a background light. Although observed earlier in skate and frog, this phenomenon has not previously been seen in an invertebrate. Furthermore, a period of hyperresponsivity exists in early dark adaptation and resembles that found in skate and frog. Thus, recovery in the light and hyperresponsivity in the dark seem to be corollaries of each other. Finally, spectral sensitivity of the ERG is determined and two peaks are found: one at 510 nm and the other at 360 nm. The former appears to be a rhodopsin-mediated sensitivity but the latter does not and they are not clearly separated by chromatic adaptation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00539180
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  • 10
    Electronic Resource
    Electronic Resource
    The contribution of pigment transitions to sensitivity changes in the barnacle photoreceptor and the correlation with the prolonged depolarizing afterpotential (1982)
    Springer
    European biophysics journal 8 (1982), S. 161-172 
    Details
    ISSN: 1432-1017
    Keywords: Photoreceptor ; Visual pigment ; Adaptation ; Facilitation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract A conditioning light can cause a decrease (adaptation) or an increase (facilitation) in the sensitivity of barnacle photoreceptors, as measured by the amplitude of the late receptor potential (LRP). We show that a net transfer of visual pigment from the rhodopsin (R) to the metarhodopsin (M) state induces a large facilitation whereas the reverse transfer results in a much smaller facilitation or even an adaptation. These effects were not due to the response to the conditioning light but to the pigment reactions. When the conditioning light did not alter the pigment population (i.e., M → M, R → R) it was followed by an intermediate degree of facilitation. These conclusions are correct for cells which have relatively low sensitivity. In sensitive cells, all pigment transitions produce adaptation. LRP facilitation and the prolonged depolarizing afterpotential (PDA) show several common characteristics with respect to pigment transitions: 1.Their magnitude increases with the amount of pigment transferred from R to M. 2. Both are depressed by the M → R transition. 3. Their production is impeded by the M → R transition. 4. The PDA itself is facilitated by the R → M transition and this facilitation decays with a time course comparable to that of LRP facilitation. These results suggest that there may be an underlying process common to LRP facilitation and PDA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00535457
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  • 11
    Electronic Resource
    Electronic Resource
    Sensitivity changes of photoreceptor cells of Hirudo medicinalis caused by changes in extracellular calcium concentration (1982)
    Springer
    European biophysics journal 8 (1982), S. 173-187 
    Details
    ISSN: 1432-1017
    Keywords: Leech photoreceptors ; Extracellular calcium ; Excitation ; Adaptation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract Extracellular recordings from the vacoule of photoreceptor cells of Hirudo medicinalis L. were performed using microelectrodes. The cells were adapted by white light flashes given at constant intervals (20 s). Response height versus relative intensity curves obtained from the same cell in physiological saline (PS) and in bathing solutions of either a) lowered calcium contents (2 ΜM/1 or less) or b) raised calcium contents (15 mM/1) were compared. The cells' adaptation state in PS was operationally defined by the ratio Q=h A /h S where h A is the response height evoked by the adapting flashes, and h S is the corresponding saturation response height. Sensitivity changes were measured by the half saturation intensity shift. Lowering extracellular calcium resulted in: 1. The response height increased and the shape of the response became more rounded and prolonged. 2. The total resistance between the vacuole and outside decreased from 8.2±1.4 MΩ (n=6) in PS to 4.6±0.4 MΩ (n=5). The resistance was independent of the cells' adaptation state. 3. A change of the cells' sensitivity occured either in direction to light adaptation or in direction to dark adaptation. It depended functionally on the ratio Q: a) if Q was less or equal to about 0.6 the cells' sensitivity increased. b) if Q was greater than 0.6 the cells' sensitivity diminished. Raising extracellular calcium decreased the sensitivity of all cells tested independent of their adaptation states in PS. The results can be interpreted under the assumptions that 1. the sensitivity of leech photoreceptor cells is inversely proportional to the intracellular free calcium concentration and Z. intracellular calcium can interact with extracellular calcium in relatively dark adapted cells whereas in relatively light adapted cells the raise of intracellular free calcium is mainly effected by a release from intracellular stores. It is assumed that a Q value of about 0.6 separates relatively light adapted cells from relatively dark adapted cells.
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    URL: http://dx.doi.org/10.1007/BF00535458
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  • 12
    Electronic Resource
    Electronic Resource
    Analysis of the rye chromosome constitution and the amount of telomeric heterochromatin in the widely and narrowly adapted hexaploid triticales (1981)
    Springer
    Theoretical and applied genetics 60 (1981), S. 145-149 
    Details
    ISSN: 1432-2242
    Keywords: Triticale ; Rye ; Hexaploids ; Adaptation ; Chromosomal substitutions ; Modified chromosomes ; Telomeric heterochromatin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Investigations were made on the rye chromosome constitution and on the presence of telomeric heterochromatin in rye chromosomes of the 26 most widely and 24 most narrowly adapted triticale strains. Among widely adapted lines, 22 (85%) had a complete rye genome and four triticales only had chromosomal R-D genome substitutions. Twenty-three (96%) of the 24 most narrowly adapted triticales had substitutions between the chromosomes of the R and D genomes. The most widely adapted triticales accumulated fewer modified rye chromosomes in comparison to narrowly adapted lines. They had from one to three rye chromosomes with heterochromatic deletions: 46% of widely adapted lines had two modified rye chromosomes; 34% had three modified rye chromosomes, and 19% had a single modified rye chromosome. In widely adapted strains, the 1R, 4R, 5R and 6R modified chromosomes were observed; they were present in 80%, 73%, 50% and 11% of the cases, respectively. The most narrowly adapted triticales had from two to four modified rye chromosomes: 58% of the strains had three modified rye chromosomes; 29% had four modified rye chromosomes and 12% had two modified rye chromosomes. The modified 4R and 5R chromosomes were present in all of these lines. The 1R (modified), 6R (modified) and 7R (modified) were found in 83%, 25% and 16%, respectively, of the narrowly adapted strains. Results support the previous observations (Pilch 1980b) that a wide adaptation of hexaploid triticales is associated with the presence of the full potential of rye genome, and that it is independent of the amount of telomeric heterochromatin possessed by rye chromosomes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00264517
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  • 13
    Electronic Resource
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    Genotype X environment interaction for bunch yield and its components in the oil palm (Elaeis guineensis, Jacq.) (1983)
    Springer
    Theoretical and applied genetics 64 (1983), S. 133-136 
    Details
    ISSN: 1432-2242
    Keywords: Stability ; Adaptation ; Fitness trait ; Bunch yield ; Oil palm ; Elaeis guineensis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary There were significant differences between hybrids for number of bunches (NB), mean bunch weight (MBW) and fresh fruit bunch yield (FFB). For the hybrid population as a whole, significant hybrid X year (environment) effects were also observed for the two yield components and for yield per se. The linear component of the hybrid X year effect was also significant. There were highly significant and positive correlations between FFB, NB and MBW hybrid means and the regression co-efficients of the hybrid means on the environmental index. There were no significant associations between these means and mean square deviations from regression (s2d) for these traits.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00272720
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  • 14
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    Genotype x environment interaction in dairy cattle and its role in breeding programmes (1983)
    Springer
    Theoretical and applied genetics 66 (1983), S. 93-99 
    Details
    ISSN: 1432-2242
    Keywords: Lactation ; Milk yield ; Herd production ; Adaptation ; Dairy cattle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Eighty thousand, one hundred and eleven records of the Israeli dairy herdbook for the period of 1973–1977 were studied and examined to determine the existence of Genotype x Environment Interaction (GxE) as affecting milk yield in kg per day between calvings. Various quantitative measures of environment were used while the genotypes were evaluated as the average performance of each sire's daughters in a whole range of environments. When the environment was evaluated as level of production, the relative importance of the interaction was found to be very low. Furthermore, the linear dependence on the interaction of the individual sires with the environments was found to be inconsistent with time, meaning that no justification was found for using specific adaptation patterns of genotypes to these environments. When lactation number and given time periods were used as environments, significant interactions were found between genotypes and environments. Results of the analyses of Genotype x Lactation interaction imply that the interaction values, to a certain degree, confused the differences between the sires when based on first lactation records. We therefore conclude that the need exists to expand the basis of sire evaluation, including the addition of data on successive lactation periods beyond the first one. We maintain that the genetic characteristic for this phenomenon is the “lactations development” of a sire, i.e., the performance of its daughters during the different lactations. The “maturing rhythm” of a sire may be regarded as a dynamic expression of the genetic makeup controlling lactation development. Furthermore, the prospect of selecting sires of bulls for early or late maturing could provide a new tool for the dairy cattle breeder.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00265180
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  • 15
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    Early ontogeny of white sucker,Catostomus commersoni, with steps of saltatory development (1980)
    Springer
    Environmental biology of fishes 5 (1980), S. 191-224 
    Details
    ISSN: 1573-5133
    Keywords: Adaptation ; Benzidine stain ; Catostomid ; Discontinuity theory ; Ecomorphology ; Embryology ; Fish ; Haemoglobin stain ; Hatching ; Peroxidase ; Thresholds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Frequent and detailed observations of arbitrary stages revealed a saltatory pattern of development in the early ontogeny of fluvial spawning white sucker. Considered as adaptations for respiration were: i) expansion of the surface area of the yolk through a change in yolk shape, ii) the presence of carotenoid pigment in the yolk, iii) a large caudal vein sinus, iv) coverage of the yolk surface with capillaries of bilaterally paired vitelline plexi, and v) a large pair of vitelline veins. The ability to swim developed slowly and well after hatching. Young suckers would therefore spend most of the eleutheroembryonic phase in the interstices of the rock substrate of the spawning ground. The change from a benthic to pelagic mode of existence occurred with swimbladder inflation and before the start of exogenous feeding.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00005355
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  • 16
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    Nitrate production in the rhizosphere of Plantago species (1981)
    Springer
    Plant and soil 61 (1981), S. 43-52 
    Details
    ISSN: 1573-5036
    Keywords: Adaptation ; Allelopathy ; Ecophysiology ; Grassland ; Plantago ; Nitrate production ; Nitrate reductase ; Nitrate uptake ; Nitrification ; Nitrifying bacteria ; Rhizosphere ; Root environment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The production of nitrate in an old established dune grassland soil and its uptake by plants was studied by comparing amounts of mineral nitrogen and numbers of nitrifying bacteria in the rhizosphere on the one hand, and on the other accumulated nitrate and levels of nitrate reductase (NaR) of individual plants of three Plantago species,i. e., P. major, P. lanceolata andP. coronopus. For these three Plantago species andP. media basal levels of NaR in the absence of nitrate were determined in plants grown in culture solutions. The basal NaR levels ofP. major andP. media (species occurring on nutrient-rich soils) were significantly higher than those ofP. lanceolata andP. coronopus (species found on nutrient-poor soils). NaR activity increased in the presence of nitrate and was suppressed by ammonium. From the numbers of nitrifying bacteria in the rhizosphere and NaR activity in the leaves it was concluded that nitrate was produced in the root environments of the three Plantago species and that the compound was taken up by the plants. NaR activities and numbers of nitrifying bacteria were higher for individuals ofP. major than for those ofP. lanceolata andP. coronopus. No correlation was found between the ammonium levels and the numbers of nitrifying bacteria in the soil, and no indications of inhibition of nitrifying bacteria in the rhizosphere were obtained. For individuals ofP. lanceolata a correlation was found between the numbers of nitrifying bacteria in the soil and NaR activity in the leaves. The results are discussed in relation to the ecological habitats of the three species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02277361
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  • 17
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    Obtention d'un mutant deRhizobium meliloti adapté aux cultures de luzerne en terres acides (1981)
    Springer
    Plant and soil 60 (1981), S. 99-110 
    Details
    ISSN: 1573-5036
    Keywords: Adaptation ; Luzerne ; Mutant ; Rhizobium meliloti ; Terres acides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Resume Un mutant acido-tolérant deR. meliloti a été isolé. Le caractère de résistance en milieu acide n'a pas été obtenu par adaptation sur des milieux de plus en plus acides mais par mutagenèses successives provoquées par la N-méthyl-N'nitroso-N-nitrosoguanidine (NTG) et sélection sur milieu acide de façon à rendre stable le caractère acido-tolérant. Ce mutant acide présente la propriété de se développer plus lentement que la souche sauvage sur milieu pauvre. Ceci ne l'empêche pas de présenter sensiblement la même efficience que cette dernière à pH voisin de la neutralité en milieu synthétique. L'étude comparative de l'efficience de la souche parentale et de la souche mutée sur la luzerne cultivée en terre acide est rendue difficile du fait de la présence de nitrates qui réduit la nodulation et inhibe l'action de la nitrogénase: par épuisement, en effectuant une culture dense de luzerne sur cette terre, il est possible de mettre en évidence ensuite l'activité symbiotique importante à pH 5,9 du mutant par rapport à la souche sauvage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02377115
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  • 18
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    Water relations, ethylene production, and morphological adaptation ofFraxinus pennsylvanica seedlings to flooding (1984)
    Springer
    Plant and soil 77 (1984), S. 183-192 
    Details
    ISSN: 1573-5036
    Keywords: Adaptation ; Adventitious roots ; Ethylene ; Flooding ; Fraxinus pennsylvanica ; Lenticels ; Turgidity ; Water potential ; Water relations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Fraxinus pennsylvanica Marsh. seedlings that were 150 days old adapted well to flooding of soil with stagnant water for 28 days. Early stomatal closure, followed by reopening as well as hypertrophy of lenticels and formation of adventitious roots on submerged portions of stems appeared to be important adaptations for flood tolerance. Leaf water potential (ψ1) was consistently higher in flooded than in unflooded seedlings, indicating higher leaf turgidity in the former. This was the result of (1) early reduction in transpiration associated with stomatal closure, and (2) subsequently increased absorption of water by the newly-formed adventitious roots as stomata reopened and transpiration increased. Waterlogging of soil was followed by large increases in ethylene content of stems, both below and above the level of submersion. Formation of hypertrophied lenticels and adventitious roots on flooded plants was correlated with increased ethylene production. However, the involvement of various compounds other than ethylene in inducing morphological changes in flooded plants is also emphasized.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02182922
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  • 19
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    Physiological, morphological, and growth responses ofPlatanus occidentalis seedlings to flooding (1982)
    Springer
    Plant and soil 66 (1982), S. 243-255 
    Details
    ISSN: 1573-5036
    Keywords: Adaptation ; Adventitious roots ; Ethylene ; Flooding ; Growth of seedlings ; Lenticels ; Platanus occidentalis ; Stomatal aperture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Flooding ofPlatanus occidentalis L. seedlings for up to 40 days induced several changes including early stomatal closure, greatly accelerated ethylene production by stems, formation of hypertrophied lenticels and adventitious roots on submerged portions of stems, and marked growth inhibition. Poor adaptation ofPlatanus occidentalis seedlings to soil inundation was shown in stomatal closure during the entire flooding period, inhibition of root elongation and branching, and death of roots. Some adaptation to flooding was indicated by (1) production of hypertrophied lenticels which may assist in exchange of dissolved gases in flood water and in release of toxic compounds, and (2) production of adventitious roots on stems which may increase absorption of water. These adaptations appeared to be associated with greatly stimulated ethylene production in stems of flooded plants. The greater reduction of root growth over shoot growth in flooded seedlings will result in decreased drought tolerance after the flood waters recede. The generally low tolerance to flooding of seedlings of species that are widely rated as highly flood tolerant is emphasized.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02183983
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  • 20
    Electronic Resource
    Electronic Resource
    Patterns of trait variation in the diploid wheats (Triticum, Aegilops) and the tetraploid speciesTriticum diccocoides (1983)
    Springer
    Plant systematics and evolution 143 (1983), S. 257-275 
    Details
    ISSN: 1615-6110
    Keywords: Angiosperms ; Poaceae ; Aegilops ; Triticum ; T. diccocoides ; wheat ; Adaptation ; trait variation ; factor analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Eighteen earliness and morphological traits were examined in from 2 to 14 lines each of 10 diploid members of the wheat complex,Triticum-Aegilops, and 15 lines of the tetraploid speciesTriticum diccocoides. In general, earliness traits have the greatest relative between line vs. within line variation of all the traits examined. Within species, earliness traits are the principle set of characters around which evolve between line trait differences, one of the most important oich is leaf dimensions. At the genus level, earliness traits are independent of leaf dimensions and plant height characters. Thus, the pattern of evolution at the genus level is different from that exhibited in each of the species. Biological and evolutionary implications of these findings are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00986608
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    Electronic Resource
    Electronic Resource
    Effects of nickel on the rates of endocytosis, motility, and proliferation inTetrahymena and determinations on the cell content of the metal (1983)
    Springer
    Protoplasma 118 (1983), S. 140-147 
    Details
    ISSN: 1615-6102
    Keywords: Nickel ; Endocytosis ; Motility ; Proliferation ; Cellular nickel content ; Adaptation ; Tetrahymena pyriformis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary At concentrations above 1 mM, nickel has a dose-dependent effect on the rate of food vacuole formation in cells in the growth medium, proteose peptone (PP); total inhibition of endocytosis occurs within 10 minutes in 6mM nickel. However, only a 10 times lower concentration of nickel is tolerated by starved cells in an inorganic salt medium, a difference which may be ascribed to the high binding property of nickel to organic material. In the PP medium, nickel affects cell motility by increasing the rate of movement at a concentration of 1 mM, and by causing immobilization after 30 minutes in 6mM nickel; a spontaneous, partial recovery of cell motility is seen after 3 hours in 6 mM nickel. The effects of nickel on endocytosis and cell motility are reversible after removal of nickel. Cell proliferation continues at a reduced rate in 1 mM nickel, while only 1 1/2 cell doublings are achieved in 3 mM nickel during a 72-hour exposure, and no proliferation occurs in 6mM nickel, where an increasing cell mortality is observed after 12 hours. The cell content of nickel relates initially to the external concentration of the metal; however, cells in 1 mM nickel are capable of maintaining a constant content of the metal, whereas in 3 mM, the rate of accumulation is reduced after 3 hours, and cells in 6mM nickel accumulate the metal at a constant rate. All nickel-treated cells contain small refractive granules, previously proposed as representing an ion-regulating system, and the apparent adaption ofTetrahymena to the effects of nickel may be ascribed to such a regulation of the intracellular concentration of the metal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01293071
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  • 22
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    Electronic Resource
    Adaptational changes of plastids in the leaves ofLigustrum ovalifolium Hassk. var.aureum at different light intensities (1984)
    Springer
    Protoplasma 122 (1984), S. 132-137 
    Details
    ISSN: 1615-6102
    Keywords: Adaptation ; Light intensity ; Ligustrum ; Plastids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The capacity of adaptation and the range of adjustment to different light conditions in fully expanded mutant leaves were studied on an aurea variety of privet (Ligustrum ovalifolium Hassk. var.aureum). Whenever the light conditions are altered leaves respond immediately. Although adaptational changes in leaf thickness are not possible, the change in colour, as well as changes in pigment concentrations take place within several days. With increasing light intensity there is a marked decline in chlorophyll concentration and the carotenoid yield becomes much higher. Under low light conditions the chlorophyll content is high, while the carotenoid concentration drops significantly. The mutant chloroplasts from green leaves always have a well developed thylakoid system. The only difference between young green leaves (DG1) and older regreened ones (DG2) is in the number of thylakoids per granum (grana in older leaves consist of more thylakoids), while the stacking degree of thylakoids remains about the same (74 and 77% respectively). Depending on the previous light conditions fine structure of plastids in yellow leaves differs considerably. Young yellow leaves (Y0) contain plastids with longitudinal arrays of dilated thylakoids and prothylakoid bodies occasionally. Plastids from primarily green leaves which turned yellow afterwards in strong sunlight (Y1) are characterized by thylakoids densely packed into cup-shaped stacks, or large vesicles originating from dilated thylakoids. The stacking degree of thylakoids in sun exposed yellow leaves (determined only in Y0 leaves) is extremely low and reaches only 29%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01279446
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    Electronic Resource
    Electronic Resource
    Quantitative topography of organelles in the liver (1981)
    Springer
    Cell & tissue research 221 (1981), S. 209-220 
    Details
    ISSN: 1432-0878
    Keywords: Liver (Rat) ; Organelle topography ; Adaptation ; Fructose ; Quantitation ; Histochemistry ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary After seven days of feeding fructose the liver of Wistar rats showed enormous accumulations of glycogen, which completely altered the original pattern of distribution of organelles. A quantitative morphological method was used to analyze these changes. The cytoplasm was mapped into arbitrary “distance classes” corresponding to concentric rings beginning at the outer nuclear membrane. This allowed the density of organelles in a given zone to be estimated. In cells filled with glycogen as a result of the fructose feeding, the following rearrangements were found: in the intermediate zone of both cellular poles (i.e., bile canalicular pole and sinusoidal pole) the mitochondria disappeared, being replaced by glycogen. The endoplasmic reticulum was accumulated in the perinuclear zone of both cellular poles, as in control animals, but was reduced throughout the rest of cytoplasm. It showed a peripheral density maximum at the biliary canalicular pole, in contrast to the cells of control animals. These changes in the distribution of the organelles and cellular “compartments” correspond to histochemical findings and demonstrate an adaptive reaction in the liver parenchyma to fructose ingestion, the organelles arranging themselves in cytoplasmic regions which still show a metabolic activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00216583
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  • 24
    Electronic Resource
    Electronic Resource
    Phenological spread in plants: A result of adaptations to environmental stochasticity? (1980)
    Springer
    Plant ecology 43 (1980), S. 83-86 
    Details
    ISSN: 1573-5052
    Keywords: Adaptation ; Colonization ; Environmental stochasticity ; Phenology ; Weather variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Plant species co-inhabiting a given geographical region often have distinetly different times of flowering. It is shown that such phenological spread, duc to short-term stochastic variation in weather variables, relaxes competition for empty sites to be colonized by diaspores. For sufficiently large spreads stable coexistence becomes possible. The applicability of the proposed hypothesis to the observed instances of phenological spread is discussed and shown to extend beyond that of other current theories.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00121020
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