Growth characteristics of three bacterial isolates from an arctic soil

1978 ◽  
Vol 24 (8) ◽  
pp. 909-914 ◽  
Author(s):  
Louise M. Nelson ◽  
D. Parkinson
Keyword(s):  
Low Temperatures ◽  
High Growth ◽  
Bacterial Isolates ◽  
Tundra Soils ◽  
Devon Island ◽  
Arctic Soil ◽  
Temperature Ranges ◽  
Effects Of Temperature ◽  
Taxonomic Characterization ◽  
Substrate Concentrations

Three bacterial isolates, a Pseudomonas sp., a Bacillus sp., and an Arthrobacter sp., commonly isolated from a hummocky sedge–moss meadow at Devon Island, N.W.T., Canada, were selected for further taxonomic characterization and for a study of the effects of temperature and limiting carbon source on growth. Pseudomonas M216 resembled P. putida and Bacillus M 153, B. carotarum. Arthrobacter M51 had growth-factor requirements which were more complex than those of any named species of that genus. The temperature ranges of growth indicated that Pseudomonas M216 and Arthrobacter M51 were psychrotrophic while Bacillus M153 was mesophilic. Growth in batch culture at limiting glucose concentrations enabled the calculation of Ks and Y values for each isolate. These were similar to those obtained for other organisms and Pseudomonas M216 and Bacillus M153 showed a high affinity for glucose. The nutritional versatility of Arthrobacter M51 and its ability to grow at low temperatures and the high growth rates and affinity of Pseudomonas M216 for low substrate concentrations may account for their competitive abilities in the natural environment, while the inability of Bacillus M153 to grow at low temperatures may limit its activity in tundra soils.

Effect of freezing and thawing on survival of three bacterial isolates from an arctic soil

1978 ◽  
Vol 24 (12) ◽  
pp. 1468-1474 ◽  
Author(s):  
Louise M. Nelson ◽  
D. Parkinson
Keyword(s):  
Storage Time ◽  
Soil Extract ◽  
High Rate ◽  
Pseudomonas Sp ◽  
Meadow Soil ◽  
Bacterial Isolates ◽  
Freezing And Thawing ◽  
Freeze Thaw ◽  
Devon Island ◽  
Arctic Soil

Three isolates, a Pseudomonas sp., Bacillus sp., and Arthrobacter sp., which had been isolated from a meadow soil at Devon Island, Canada, were subjected to freezing and thawing at low rates under various conditions. When cells were frozen in sand or soil, survival was dependent on moisture level, storage time, and thaw rate. Pseudomonas M216 was most susceptible to freeze–thaw damage under these conditions. Arthrobacter M51 was the most resistant of the three isolates when frozen in sand or soil and when frozen at a high rate after growth at varing rates at 5 and 15 °C in carbon- or nitrogen-limited media. Pseudomonas M216 was more sensitive to freeze-thaw damage when NaCl was present in the freezing menstruum, even at low freezing rates. Survival of cells frozen in growth medium, water, saline, and soil extract was not affected by the freezing rate when it was less than 1 °C min−1. Soil extract did not protect cells from freeze–thaw damage any more than water and for Arthrobacter M51 survival was decreased when it was frozen in soil extract.

Effect of starvation on survival of three bacterial isolates from an arctic soil

1978 ◽  
Vol 24 (12) ◽  
pp. 1460-1467 ◽  
Author(s):  
Louise M. Nelson ◽  
D. Parkinson
Keyword(s):  
Survival Rates ◽  
Starvation Period ◽  
Bacterial Isolates ◽  
Starvation Stress ◽  
Gradual Decline ◽  
Carbon And Nitrogen ◽  
Devon Island ◽  
Endogenous Metabolism ◽  
Arctic Soil ◽  
Endogenous Substrates

Three isolates, a Pseudomonas sp., a Bacillus sp. and an Arthrobacter sp., which had been isolated from a meadow soil at Devon Island, Canada, were subjected to starvation under varying conditions. The viabilities of the three isolates during starvation for 30 days in a carbon-free medium was assessed after the organisms had been grown continuously at varying rates in carbon- and nitrogen-limited media at 5 and 15 °C. Pseudomonas M216 was the most resistant to starvation stress. Bacillus M153 the least, and Arthrobacter M51 was intermediate in its response. Cells grown and starved at 5 °C survived longer than those at 15 °C. Carbon-limited Bacillus and Arthrobacter cells grown at high rates prior to starvation survived longer than those grown slowly, while in nitrogen-limited Arthrobacter the reverse was observed. The pattern of endogenous metabolism of the three isolates during starvation at 15 °C for 10 days was similar to that observed in other organisms. Levels of endogenous substrates such as carbohydrate and protein showed a rapid decrease in the initial 20 h of starvation, followed by a gradual decline over the remainder of the starvation period. The rates of endogenous metabolism of the isolates were positively correlated with their survival rates during starvation.

Temperature acclimation of the caudal photoreceptor response in the crayfish Orconectes rusticus (Girard)

1988 ◽  
Vol 66 (5) ◽  
pp. 1168-1171 ◽  
Author(s):  
Jim H. Belanger
Keyword(s):  
Stimulus Intensity ◽  
Low Temperatures ◽  
Temperature Acclimation ◽  
Thermal Capacity ◽  
Maximum Frequency ◽  
Orconectes Rusticus ◽  
Temperature Dependent ◽  
Caudal Photoreceptor ◽  
Effects Of Temperature ◽  
Nerve Cords

Crayfish (Orconectes rusticus (Girard)) were acclimated for 3 weeks at 5 and 25 °C. The effects of temperature and temperature acclimation on the latency, maximum frequency, and sensitivity to stimulus intensity of the caudal photoreceptor response were examined in isolated abdominal nerve cords. Each of these components was temperature dependent. The maximum frequency of the response showed thermal capacity acclimation but latency did not. Caudal photoreceptor response was insensitive to stimulus intensity at low temperatures but acclimation improved sensitivity.

EAR LENGTH AND SPIKELET NUMBER OF WHEAT GROWN AT DIFFERENT TEMPERATURES AND LIGHT INTENSITIES

1965 ◽  
Vol 43 (3) ◽  
pp. 345-353 ◽  
Author(s):  
D. J. C. Friend
Keyword(s):  
Light Intensity ◽  
Low Temperatures ◽  
Dry Weight ◽  
High Light ◽  
Morphological Development ◽  
Spikelet Number ◽  
Light Intensities ◽  
Different Temperatures ◽  
Total Plant ◽  
Effects Of Temperature

The number of spikelets on the differentiating inflorescence and the ear at anthesis was highest at high light intensities and at low temperatures. The length of the developing inflorescence and the ear, the height of the main stem, and the total plant dry weight at the time of anthesis were also greatest under these conditions.These results are related to differential effects of temperature and light intensity on the rates and duration of apical elongation, morphological development of the ear, and spikelet formation.

Ion Beam Induced Epitaxial Regrowth and Interfacial Amorphization of Compound Semiconductors

1996 ◽  
Vol 438 ◽  
Author(s):  
E. Glaser ◽  
T. Fehlhaber ◽  
R. Schulz ◽  
T. Bachmann ◽  
P. Gaiduk
Keyword(s):  
Ion Beam ◽  
High Growth ◽  
Orientation Dependence ◽  
Critical Temperatures ◽  
Epitaxial Regrowth ◽  
Limited Temperature ◽  
Temperature Ranges ◽  
Compound Materials ◽  
Kinetics Of ◽  
Induced Crystallization

AbstractA review of MeV-ion beam induced crystallization (IBIEC) and interfacial amorphization (IBIIA) in III-V compounds (GaAs, InAs, GaP, InP) is given. The kinetics of IBIEC and IBIIA is studied as a function of the temperature, the density of the displacements v, and the ion dose rate j. Reversal temperatures TR for IBIEC ↔ IBIIA transitions are determined for the different materials showing characteristic dependences on v and j. The IBIEC rate is shown to be controlled by point defect diffusion towards the a/c-interface and additionally modified by the interface structure. The suppression of microtwin and stacking fault formation during IBIEC is explained by the fact that the ion beam modifies the orientation dependence of the crystallization kinetics avoiding the disintegration and (111)-faceting of the (100)-interface. For all the compound materials investigated the IBIEC process is stopped above critical temperatures and doses. The capture of diffasing defects by crystallites growing in the amorphous layers is considered to be responsible for the stopping of the IBIEC interface. Ways are demonstrated to avoid stopping, to achieve complete epitaxial regrowth also of thick layers, and to minimize the generation of stable damage in the crystallized layers. The limited temperature ranges for undisturbed IBIEC and IBIIA in III/V-compounds are explained by low nucleation barriers and high growth rates both of crystallites and of amorphous zones.

scholarly journals Flavobacterium sp. Strain 4221 and Pedobacter sp. Strain 4236 β-1,3-Glucanases That Are Active at Low Temperatures

2008 ◽  
Vol 74 (22) ◽  
pp. 7070-7072 ◽  
Author(s):  
Mikkel A. Rasmussen ◽  
Søren M. Madsen ◽  
Peter Stougaard ◽  
Mads G. Johnsen
Keyword(s):  
Escherichia Coli ◽  
Lactococcus Lactis ◽  
Low Temperatures ◽  
Cell Walls ◽  
The Arctic ◽  
Bacterial Isolates ◽  
Fungal Cell ◽  
Fungal Cell Walls

ABSTRACT Secretion of β-1,3-glucanases by the arctic bacterial isolates 4221 and 4236, related to the genera Flavobacterium and Pedobacter, was discovered. Escherichia coli and Lactococcus lactis expression of β-1,3-glucanases Glc4221-1 and Glc4236-1 from the respective isolates was achieved. The enzymes hydrolyzed fungal cell walls and retained activity at low temperatures.

Effects of Temperature on Responses of the Gonads of Green Sunfish (Lepomis cyanellus) to Treatment with Carp Pituitaries and Testosterone Propionate

1973 ◽  
Vol 30 (7) ◽  
pp. 905-912 ◽  
Author(s):  
Calvin M. Kaya
Keyword(s):  
Low Temperatures ◽  
Elevated Temperatures ◽  
Testosterone Propionate ◽  
Lepomis Cyanellus ◽  
Pituitary Glands ◽  
Effects Of Temperature ◽  
Gonadal Recrudescence ◽  
Green Sunfish ◽  
The Brain ◽  
Stimulation Of

Previous investigations have demonstrated that stimulation of gonadal recrudescence in the green sunfish (Lepomis cyanellus) depends on the concurrent presence of long photoperiods (15 hr) and elevated temperatures (> 15 C). The present investigation indicates that recrudescence can be stimulated in seasonally regressed ovaries and testes by injections of a crude extract of fish pituitary glands, and in testes by testosterone propionate, but only under elevated temperature. The low temperatures that block gonadal responses to long photoperiods also effectively prevent gonadal responses to administered hormones. These observations indicate that the responsiveness of the gonads of this species to stimulating hormones is markedly modified by temperature; however, the results do not obviate the possibility that secretion of gonadotropins by the brain–pituitary system may also be affected.

The effects of temperature and humidity on the oviposition rate of Tribolium castaneum (Hbst.) (Coleoptera, Tenebrionidae)

1962 ◽  
Vol 53 (2) ◽  
pp. 301-310 ◽  
Author(s):  
R. W. Howe
Keyword(s):  
Tribolium Castaneum ◽  
Low Temperatures ◽  
Adult Life ◽  
Oviposition Rate ◽  
Optimum Temperature ◽  
Preoviposition Period ◽  
Innate Capacity ◽  
Effects Of Temperature ◽  
Capacity For Increase ◽  
Coleoptera Tenebrionidae

The rate of oviposition of isolated pairs of Tribolium castaneum (Hbst.) on finely divided wheatfeed was measured over the entire adult life at 25°C. and 70 per cent. R.H. It was also measured over a period of seven weeks from the start of oviposition at 30 and 70 per cent. R.H. at 25, 30 and 35°C., respectively, at 70 per cent. R.H. only at 22·5, 27·5, 32·5 and 37·5°C. and at 2 per cent. R.H. at 30°C.At 25°C. and 70 per cent. R.H. each female laid, on the average, 360 eggs at the rate of 2·5 per day for about one hundred days and then at a decreasing rate for the next hundred days. When this experiment was repeated over a seven-week period, each female laid on average about 3 eggs per day. At 70 per cent. R.H., the optimum temperature for oviposition was about 32·5°C., at which about 11 eggs per day per female were laid over the seven-week period. These rates fell to just over 2 per day at 22·5°C. Only one egg was laid by 15 females at 20°C. At 37·5°C. the rate was about 10 eggs per day initially but it declined to about 3 per day by the end of seven weeks, whereas at lower temperatures the decline in laying was slight. Compared with 70 per cent. R.H., the oviposition rate at 30 per cent. R.H. was almost halved at 25°C., but was only slightly reduced at 35°C. At 30°C. and 2 per cent. R.H., females laid well, averaging over 4 eggs per female per day. The periodic provision of water for drinking at 25°C. and 30 per cent. R.H. depressed oviposition.The preoviposition period was 2 days at 37·5°C. and increased steadily at lower temperatures to 10 days at 22·5°C. It also varied more between females at low temperatures.The number of eggs recovered in this work was lower than the number obtained by Park & Frank (1948), who used considerably more food in their oviposition chambers. In this work, some eggs were eaten by the adult beetles. However, the innate capacity for increase of the species calculated on these data is extremely high, and could not be maintained for long because of the cannibalistic habits of this species.

Monotreme Cell-Cycles and the Evolution of Homeothermy

1988 ◽  
Vol 36 (5) ◽  
pp. 573 ◽  
Author(s):  
JM Watson ◽  
JAM Graves
Keyword(s):  
Body Temperature ◽  
Cycle Time ◽  
Low Temperatures ◽  
Evolutionary History ◽  
The Body ◽  
Lethal Temperature ◽  
Cell Cycles ◽  
M Phase ◽  
Effects Of Temperature ◽  
High And Low Temperatures

We have studied the effects of temperature on the phases of the cell cycle in cells derived from the monotreme mammals, platypus and echidna, which have the unusually low body temperature of 32�C. We report here that M phase and the cycle time conform to expectations, but in the case of cycle time this is due to different effects of high and low temperatures on GI, G2 and S phases. The finding that the G2 and S phases apparently have an inverse linear relationship with temperature up to 37�C (the upper lethal temperature) suggests that the low body temperature of the monotremes is not primitive, but rather has been the result of a lowering of the body temperature during their evolutionary history.

Singlet Mechanism for Trans → Cis Photoisomerization of Quaternary Salts of 4-Substituted 4′-Azastilbenes (R = CN, H, CH3, and OCH3) and their Quinolinium Analogues. VIII

1985 ◽  
Vol 40 (5) ◽  
pp. 525-537 ◽  
Author(s):  
H. Görner ◽  
A. Fojtik ◽  
J. Wróblewski ◽  
L. J. Currell
Keyword(s):  
Triplet State ◽  
Low Temperatures ◽  
Room Temperature ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Ion Pairs ◽  
Laser Flash ◽  
Quantum Yields ◽  
Polar Solvents ◽  
Effects Of Temperature

The trans → cis photoisomerization of a series of substituted stilbazolium salts (At+X− , At+: trans-1-alkyl-4-[4-R-styryl]-pyridinium and -quinolinium, R = CN. H, CH3 and OCH3, X− = I and ClO4−) was studied by laser flash photolysis and steady state irradiation measurements. The quantum yields of cis ⇄ trans photoisomerization (ϕc → t and ϕt → c ) and of fluorescence of the trans isomers (ϕf) were determined in several solvents at room temperature and at low temperatures in mixtures of either 2-methyltetrahydrofuran-dichloromethane or ethanolmethanol (E-M). In polar solvents at room temperature ϕt → c is substantial ( ≧ 0.3) and ϕf is small (10−3-10−2). Competition of fluorescence and an activated step in the trans → cis pathway is indicated by the effects of temperature on ϕf and ϕt → c (activation energy: 2 - 3 kcal/mol). A transient, observed only at low temperatures (lifetime τT > 0.5 ms in E-M below -170°C), is assigned to the lowest triplet state with trans configuration. On the basis of the effects of temperature on ϕf, ϕt → c , and the triplet yield and those of quenchers on ϕf and ϕt → c , involvement of the triplet state in the twisting process at room temperature is excluded. Therefore, a singlet mechanism is suggested for the trans → cis photoisomerization of the stilbazolium salts examined. Significant reduction of ϕt → c for iodides in solvents of moderate polarity, where ion pairs are present, is accounted for by photoinduced electron transfer in competition to trans → cis photoisomerization.

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