共查询到20条相似文献,搜索用时 31 毫秒
1.
M. A. Ferrero G. R. Castro C. M. Abate M. D. Baigorí F. Siñeriz 《Applied microbiology and biotechnology》1996,45(3):327-332
Bacillus licheniformis MIR 29 has been isolated and produces extracellular proteases. It is able to grow at temperatures up to 60 °C and at pH values
up to 9.0. Casein was the best carbon source for production of a thermostable protease activity which, in some conditions,
is 90% extracellular. The synthesis of alkaline protease is not constitutive; different levels of production were found with
different carbon and nitrogen sources. Casein was thought to be an inducer of enzyme synthesis. The optimal pH and temperature
of the enzyme activity were 12 °C and 60 °C, respectively. The enzyme was stable up to 60 °C in the absence of stabilizers.
The protease activity was inhibited with phenylmethylsulphonyl fluoride, indicating a serine-protease activity. The proteolytic
activity was lowered by molecules present in the culture supernatant, which include amino acids and peptides, indicating end-product
inhibition. Electrophoresis assay on denaturating gels showed two bands with alkaline protease activity, in the 25 to 40-kDa
molecular mass range.
Received: 7 June 1995/Received revision: 14 September 1995/Accepted: 20 September 1995 相似文献
2.
The influence of low temperature (5–29 °C) on the methanogenic activity of non-adapted digested sewage sludge and on temperature/leachate-adapted
biomass was assayed by using municipal landfill leachate, intermediates of anaerobic degradation (propionate) and methane
precursors (acetate, H2/CO2) as substrates. The temperature dependence of methanogenic activity could be described by Arrhenius-derived models. However,
both substrate and adaptation affected the temperature dependence. The adaptation of biomass in a leachate-fed upflow anaerobic
sludge-blanket reactor at approximately 20 °C for 4 months resulted in a sevenfold and fivefold increase of methanogenic activity
at 11 °C and 22 °C respectively. Both acetate and H2/CO2 were methanized even at 5 °C. At 22 °C, methanogenic activities (acetate 4.8–84 mM) were 1.6–5.2 times higher than those
at 11 °C. The half-velocity constant (K
s) of acetate utilization at 11 °C was one-third of that at 22 °C while a similar K
i was obtained at both temperatures. With propionate (1.1–5.5 mM) as substrate, meth‐anogenic activities at 11 °C were half
those at 22 °C. Furthermore, the residual concentration of the substrates was not dependent on temperature. The results suggest
that the adaptation of biomass enables the achievement of a high treatment capacity in the anaerobic process even under psychrophilic
conditions.
Received: 23 December 1996 / Received last revision: 18 June 1997 / Accepted: 23 June 1997 相似文献
3.
C. Suresh A. K. Dubey S. Srikanta S. Umesh Kumar N. G. Karanth 《Applied microbiology and biotechnology》1999,51(5):673-675
A UV-induced mutant strain of Aspergillus niger (CFTRI-1105-U9) overproduced a starch-hydrolysing enzyme with properties characteristically different from the known amylases
of the fungus. The purified enzyme of 4.0 pI had an apparent molecular mass of 125 kDa and it dextrinised starch and then
saccharified the dextrins. Patterns of the enzyme activity on starch, resulting in glucose at 60 °C and glucose, maltose and
maltodextrins at 70 °C as primary products, suggested significant applications for the enzyme in starch-processing industries.
Received: 29 October 1998 / Received revision: 11 January 1999 / Accepted: 19 January 1999 相似文献
4.
Torres R Ramón F de la Mata I Acebal C Castillón MP 《Applied microbiology and biotechnology》1999,53(1):81-84
At 28 °C, Streptomyces lavendulae produced high levels of penicillin V acylase (178 IU/l of culture) when grown on skim milk as the sole nutrient source for
275 h. The enzyme showed catabolite repression by glucose and was produced in the stationary phase of growth. Penicillin V
was a good inducer of penicillin V acylase formation, while phenoxyacetic acid, the side-chain moiety of penicillin V, did
not alter enzyme production significantly. The enzyme was stable between pH 6 and 11 and at temperatures from 20 °C to 55 °C.
This extracellular enzyme was able to hydrolyse natural penicillins and unable to hydrolyse penicillin G.
Received: 22 March 1999 / Received revision: 16 June 1999 / Accepted: 20 June 1999 相似文献
5.
A recessive temperature dependent shooty mutant (tds) of Nicotiana tabacum L. (W38) is described. The mutant phenotype is expressed at low temperature (21 °C). Mutant characteristics include thick,
narrow leaves with abnormal mesophyll cells, short internodes, and near absence of apical dominance. Most plants remain vegetative
and the occasional flower has petaloid stamens. High temperature (30 °C) reverses the mutant phenotype, with formation of
normal leaves and restoration of apical dominance. However, many flowers still have petaloid stamens. Reciprocal grafting
and auxin-cytokinin interaction experiments do not suggest shifts in auxin-cytokinin balance. Overall, this mutant bears some
resemblance to transgenic tobacco overexpressing homeodomain genes from maize and Arabidopsis.
Received: 23 August 1996 / Accepted: 24 September 1996 相似文献
6.
A Clostridium thermocellum gene, xynX, coding for a xylanase was cloned and the complete nucleotide sequence was determined. The xylanase gene of Clostridium thermocellum consists of an ORF of 3261 nucleotide encoding a xylanase (XynX) of 1087 amino acid residues (116 kDa). Sequence analysis
of XynX showed a multidomain structure that consisted of four different domains: an N-terminal thermostabilizing domain homologous
to sequences found in several thermophilic enzymes, a catalytic domain homologous to family 10 glycosyl hydrolases, a duplicated
cellulose-binding domain (CBD) homologous to family IX CBDs, and a triplicated S-layer homologous domain. A deletion mutant
of xynX having only the catalytic region produced a mutant enzyme XynX-C which retained catalytic activity but lost thermostability.
In terms of half-life at 70 °C, the thermostability of XynX-C was about six times lower than that of the other mutant enzyme,
XynX-TC, produced by a mutant containing both the thermostabilizing domain and the catalytic domain. The optimum temperature
of XynX-C was about 5–10 °C lower than that of XynX-TC.
Received: 12 January 2000 / Received revision: 24 April 2000 / Accepted: 1 May 2000 相似文献
7.
Wilson RS James RS Johnston IA 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2000,170(2):117-124
Among amphibians, the ability to compensate for the effects of temperature on the locomotor system by thermal acclimation
has only been reported in larvae of a single species of anuran. All other analyses have examined predominantly terrestrial
adult life stages of amphibians and found no evidence of thermal acclimatory capacity. We examined the ability of both tadpoles
and adults of the fully aquatic amphibian Xenopus laevis to acclimate their locomotor system to different temperatures. Tadpoles were acclimated to either 12 °C or 30 °C for 4 weeks
and their burst swimming performance was assessed at four temperatures between 5 °C and 30 °C. Adult X. laevis were acclimated to either 10 °C or 25 °C for 6 weeks and their burst swimming performance and isolated muscle performance
was determined at six temperatures between 5 °C and 30 °C. Maximum swimming performance of cold-acclimated X. laevis tadpoles was greater at cool temperatures and lower at the highest temperature in comparison with the warm-acclimated animals.
At the test temperature of 12 °C, maximum swimming velocity of tadpoles acclimated to 12 °C was 38% higher than the 30 °C-acclimation
group, while at 30 °C, maximum swimming velocity of the 30 °C-acclimation group was 41% faster than the 12 °C-acclimation
group. Maximum swimming performance of adult X. laevis acclimated to 10 °C was also higher at the lower temperatures than the 25 °C acclimated animals, but there was no difference
between the treatment groups at higher temperatures. When tested at 10 °C, maximum swimming velocity of the 10 °C-acclimation
group was 67% faster than the 25 °C group. Isolated gastrocnemius muscle fibres from adult X. laevis acclimated to 10 °C produced higher relative tetanic tensions and decreased relaxation times at 10 °C in comparison with
animals acclimated to 25 °C. This is only the second species of amphibian, and the first adult life stage, reported to have
the capacity to thermally acclimate locomotor performance.
Accepted: 28 October 1999 相似文献
8.
Sanni P. Voutilainen Harry Boer Marika Alapuranen Janne J?nis Jari Vehmaanper? Anu Koivula 《Applied microbiology and biotechnology》2009,83(2):261-272
Two different types of approach were taken to improve the hydrolytic activity towards crystalline cellulose at elevated temperatures
of Melanocarpus albomyces Cel7B (Ma Cel7B), a single-module GH-7 family cellobiohydrolase. Structure-guided protein engineering was used to introduce an additional
tenth disulphide bridge to the Ma Cel7B catalytic module. In addition, a fusion protein was constructed by linking a cellulose-binding module (CBM) and a linker
from the Trichoderma reesei Cel7A to the C terminus of Ma Cel7B. Both approaches proved successful. The disulphide bridge mutation G4C/M70C located near the N terminus, close to the
entrance of the active site tunnel of Ma Cel7B, led to improved thermostability (ΔT
m = 2.5°C). By adding the earlier found thermostability-increasing mutation S290T (ΔT
m = 1.5°C) together with the disulphide bridge mutation, the unfolding temperature was increased by 4°C (mutant G4C/M70C/S290T)
compared to that of the wild-type enzyme, thus showing an additive effect on thermostability. Both disulphide mutants had
increased activity towards microcrystalline cellulose (Avicel) at 75°C, apparently solely because of their improved thermostability.
The addition of a CBM also improved the thermostability (ΔT
m = 2.5°C) and caused a clear (sevenfold) increase in the hydrolysis activity of Ma Cel7B towards Avicel at 70°C. 相似文献
9.
A total of sixteen spontaneously generated, independent suppressor mutants was isolated from a mutant (divE42) of Escherichia coli K12 that is defective in cell division. One of the suppressor mutants, designated TR4, had a novel phenotype: it was able
to grow at 42° C but not at 32° C. The Kohara genomic library was screened for complementing clones. Clone 148 was able to
complement the mutation responsible for the cold-sensitive phenotype, and the gene for trigger factor (tig), which encodes a ribosome-associated peptidyl-prolyl cis/trans isomerase, was identified as the mutated gene by deletion analysis with the insert DNA from clone 148. DNA sequencing revealed
that the mutation in the tig gene of the TR4 suppressor mutant was a single nucleotide insertion (+A) at a distance of 834 nucleotides from the initiation
codon for this enzyme. When the wild-type tig gene was introduced into the TR4 suppressor mutant, the bacteria were able to grow at 32° C but not at 42° C, an indication
that the intergenic suppressor mutation was recessive to the wild-type allele. A model is proposed that accounts for the phenotypes
of the divE42 mutant and the TR4 suppressor mutant.
Received: 3 March 1998 / Accepted: 14 July 1998 相似文献
10.
A. Brunella M. Graf M. Kittelmann K. Laumen O. Ghisalba 《Applied microbiology and biotechnology》1997,47(5):515-520
Rhodococcus equi Ac6 was found to express an inducible (S )-specific N-acetyl-1-phenylethylamine amidohydrolase. Optimal bacterial growth and amidohydrolase expression were both observed around
pH 6.5. Purification of the enzyme to a single band in a Coomassie-blue-stained sodium dodecyl sulfate/polyacrylamide gel
(SDS-PAGE) was achieved by ammonium sulfate precipitation of R. equi Ac6 crude extract and column chromatographies on Fractogel TSK Butyl-650(S) and Superose 12HR. At pH 7.0 and 30 °C the amidohydrolase
had a half-life of around 350 days; at 44 °C it was only 10 min. Except for Ni2+ and, to some extent, Zn2+ and Co2+, the enzyme was neither strongly influenced by metal cations nor by chelating agents, but was inhibited by 95% at 0.1 mM
phenylmethylsulfonyl fluoride. The molecular mass of the native enzyme was estimated to be 94 kDa by gel filtration and 50 kDa
by SDS-PAGE, suggesting a dimeric structure. Specificity experiments revealed a spectrum of related N-acetylated compounds being hydrolyzed with variable enantiomeric selectivities.
Received: 20 September 1996 / Received revision: 23 December 1996 / Accepted: 30 December 1996 相似文献
11.
Two thermophilic anaerobic bacterial consortia (ALK-1 and LLNL-1), capable of degrading the aromatic fuel hydrocarbons, benzene,
toluene, ethylbenzene, and the xylenes (BTEX compounds), were developed at 60 °C from the produced water of ARCO'S Kuparuk
oil field at Alaska and the subsurface water at the Lawrence Livermore National Laboratory gasoline-spill site, respectively.
Both consortia were found to grow at 45–75 °C on BTEX compounds as their sole carbon and energy sources with 50 °C being the
optimal temperature. With 3.5 mg total BTEX added to sealed 50-ml serum bottles, which contained 30 ml mineral salts medium
and the consortium, benzene, toluene, ethylbenze, m-xylene, and an unresolved mixture of o- and p-xylenes were biodegraded by 22%, 38%, 42%, 40%, and 38%, respectively, by ALK-1 after 14 days of incubation at 50 °C. Somewhat
lower, but significant, percentages of the BTEX compounds also were biodegraded at 60 °C and 70 °C. The extent of biodegradation
of these BTEX compounds by LLNL-1 at each of these three temperatures was slightly less than that achieved by ALK-1. Use of
[ring-14C]toluene in the BTEX mixture incubated at 50 °C verified that 41% and 31% of the biodegraded toluene was metabolized within
14 days to water-soluble products by ALK-1 and LLNL-1, respectively. A small fraction of it was mineralized to 14CO2. The use of [U-14C]benzene revealed that 2.6%–4.3% of the biodegraded benzene was metabolized at 50 °C to water-soluble products by the two
consortia; however, no mineralization of the degraded [U-14C]benzene to 14CO2 was observed. The biodegradation of BTEX at all three temperatures by both consortia was tightly coupled to sulfate reduction
as well as H2S generation. None was observed when sulfate was omitted from the serum bottles. This suggests that sulfate-reducing bacteria
are most likely responsible for the observed thermophilic biodegradation of BTEX in both consortial cultures.
Received: 12 July 1996 / Received revision: 31 December 1996 / Accepted: 31 January 1997 相似文献
12.
D. Coquard M. Huecas M. Ott J. M. van Dijl A. P. G. M. van Loon H.-P. Hohmann 《Molecular & general genetics : MGG》1997,254(1):81-84
A mutation leading to roseoflavin resistance and deregulated riboflavin biosynthesis was mapped in the genome of the riboflavin-overproducing
Bacillus subtilis strains RB52 and RB50 at map position 147°. The chromosomal location indicates that the deregulating mutation in RB52 and
RB50 is an allele of the previously identified ribC mutation. We cloned the ribC gene and found that it encodes a putative 36-kDa protein. Surprisingly, RibC has significant sequence similarity to flavin
kinases and FAD synthases from various other bacterial species. By comparing the deduced amino acid sequence of RibC from
the wild-type parent strain of RB50 with the RibC sequence from the riboflavin-overexpressing RB50 mutant we identified a
point mutation that resulted in a Gly to Ser exchange in the C-terminal region of the product
Received: 3 June 1996 / Accepted: 19 October 1996 相似文献
13.
Changes in selected aspects of immune function in the leopard frog, Rana pipiens, associated with exposure to cold 总被引:3,自引:0,他引:3
Gregory D. Maniero Cynthia Carey 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1997,167(4):256-263
The effect of exposure to low temperatures (5 °C) on lymphocyte proliferation, leukocyte populations, and serum complement
levels was examined in the northern leopard frog, Rana pipiens. Proliferation of T lymphocytes in response to phytohemagglutinin stimulation was significantly decreased in frogs kept for
2, 3, and 5 months at 5 °C compared to that of animals kept at 22 °C. A significant increase in the average percentage of
neutrophils and a decrease in the mean percentage of eosinophils was observed in the blood of frogs held for 5 months in the
cold compared to animals held at 22 °C for the same length of time. Mean serum complement activity after 1 month at 5 °C was
significantly reduced in comparison to animals held at 22 °C and was not detectable after 5 months in the cold. Recovery of
complement levels at room temperature (22 °C) was also examined after cold exposure. Complement levels were significantly
higher than controls (at 22 °C) in frogs returned to 22 °C for 7 and 14 days after 5 months in the cold. After frogs were
held at 5 °C for 1 month, serum complement levels increased significantly within 2 days after returning to 22 °C and continued
to rise 5 and 9 days after warming. Injections with Aeromonas hydrophila following a 5-week exposure to 5 °C failed to cause death or observable symptoms of disease in frogs that were returned to
22 °C.
Accepted: 20 November 1996 相似文献
14.
M. Eriksson G. Dalhammar A.-K. Borg-Karlson 《Applied microbiology and biotechnology》1999,51(4):532-535
A hydrocarbon mixture containing p-xylene, naphthalene, Br-naphthalene and straight aliphatic hydrocarbons (C14 to C17) was aerobically degraded without lag phase by a natural uncontaminated potting soil at 20 °C and 6 °C. Starting concentrations
were approximately 46 ppm for the aromatic and 13 ppm for the aliphatic compounds. All aliphatic hydrocarbons were degraded
within 5 days at 20 °C, to levels below detection (ppb levels) but only down to 10% of initial concentration at 6 °C. Naphthalene
was degraded within 12 days at 20 °C and unaffected at 6 °C. At 20 °C p-xylene was degraded within 20 days, but no degradation occurred at 6 °C. Br-naphthalene was only removed down to 30% of initial
concentration at 20 °C, with no significant effect at 6 °C. The biodegradation was monitored with head space solid-phase microextraction
and gas chromatography–mass spectrometry.
Received: 5 October 1998 / Received revision: 4 December 1998 / Accepted: 5 December 1998 相似文献
15.
The period length of the circadian conidiation rhythm was examined in a mutant strain of Neurospora crassa, un-18, that is temperature sensitive for mycelial growth. The un-18 mutant showed a temperature-sensitive phenotype with respect to both mycelial growth and the period length of the conidiation
rhythm. Below 22° C, the un-18 mutation did not affect the period length, but at temperatures between 22° C and 32° C, the period length of the un-18 mutant was ∼2 h longer than that of the wild-type strain. The un-18
+ gene was cloned and was found to encode the second-largest subunit of RNA polymerase I, which is involved in the synthesis
of rRNA. These results indicate that a defect in ribosome synthesis, which must result in a lower rate of protein synthesis,
lengthens the period of the circadian conidiation rhythm in Neurospora.
Received: 17 October 1997 / Accepted: 26 April 1998 相似文献
16.
Adaptation and acclimation of growth and photosynthesis of five Antarctic red algae to low temperatures 总被引:2,自引:0,他引:2
Temperature requirements for growth, photosynthesis and dark respiration were determined for five Antarctic red algal species.
After acclimation, the stenothermal species Gigartina skottsbergii and Ballia callitricha grew at 0 or up to 5 °C, respectively; the eurythermal species Kallymenia antarctica, Gymnogongrus antarcticus and Phyllophora ahnfeltioides grew up to 10 °C. The temperature optima of photosynthesis were between 10 and 15 °C in the stenothermal species and between
15 and 25 °C in the eurythermal species, irrespective of the growth temperature. This shows that the temperature optima for
photosynthesis are located well below the optima from species of other biogeographical regions, even from the Arctic. Respiratory
rates rose with increasing temperatures. In contrast to photosynthesis, no temperature optimum was evident between 0 and 25 °C.
Partial acclimation of photosynthetic capacity to growth temperature was found in two species. B. callitricha and Gymnogongrus antarcticus acclimate to 0 °C, and 5 and 0 °C, respectively. But acclimation did in no case lead to an overall shift in the temperature
optimum of photosynthesis. B. callitricha and Gymnogongrus antarcticus showed acclimation of respiration to 5 °C, and P. ahnfeltioides to 5 and 10 °C, resulting in a temperature independence of respiration when measured at growth temperature. With respect
to the acclimation potential of the species, no distinction can be made between the stenothermal versus the eurythermal group.
(Net)photosynthetic capacity:respiration (P:R) ratios showed in all species highest values at 0 °C and decreased continuously to values lower than 1.0 at 25 °C. In turn,
the low P:R ratios at higher temperatures are assumed to determine the upper temperature growth limit of the studied species. Estimated
daily carbon balance reached values between 4.1 and 30.7 mg C g−1 FW day−1 at 0 °C, 16:8 h light/dark cycle, 12–40 μmol m−2 s−1.
Received: 4 November 1999 / Accepted: 7 March 2000 相似文献
17.
A number of nutritional factors influencing growth and glucose oxidase (EC 1.1.3.4) production by a newly isolated strain
of Penicillium pinophilum were investigated. The most important factors for glucose oxidase production were the use of sucrose as the carbon source,
and growth of the fungus at non-optimal pH 6.5. The enzyme was purified to apparent homogeneity with a yield of 74%, including
an efficient extraction step of the mycelium mass at pH 3.0, cation-exchange chromatography and gel filtration. The relative
molecular mass (M
r) of native glucose oxidase was determined to be 154 700 ± 4970, and 77 700 for the denatured subunit. Electron-microscopic
examinations revealed a sandwich-shaped dimeric molecule with subunit dimensions of 5.0 × 8.0 nm. Glucose oxidase is a glycoprotein
that contains tightly bound FAD with an estimated stoichiometry of 1.76 mol/mol enzyme. The enzyme is specific for d-glucose, for which a K
m value of 6.2 mM was determined. The pH optimum was determined in the range pH 4.0–6.0. Glucose oxidase showed high stability
on storage in sodium citrate (pH 5.0) and in potassium phosphate (pH 6.0), each 100 mM. The half-life of the activity was
considerably more than 305 days at 4 °C and 30 °C, and 213 days at 40 °C. The enzyme was unstable at temperatures above 40 °C
in the range pH 2.0–4.0 and at a pH above 7.0.
Received: 18 November 1996 / Received revision: 3 March 1997 / Accepted: 7 March 1997 相似文献
18.
Supercooling points, lower lethal temperatures, and the effect of short-term exposures to low temperatures were examined
during both winter and summer in the adults of six weevil species from three different habitats on Marion Island. Upper lethal
limits and the effects of short-term exposure to high temperatures were also examined in summer-acclimatized adult individuals
of these species. Bothrometopus elongatus, B. parvulus, B. randi, Ectemnorhinus marioni, and E. similis were freeze tolerant, but had high lower lethal temperatures (−7 to −10°C). Seasonal variation in these parameters was not
pronounced. Physical conditions of the habitat appeared to have little effect on cold hardiness parameters because the Ectemnorhinus species occur in very wet habitats, whereas the Bothrometopus species inhabit drier areas. The adults of these weevil species are similar to other high southern latitude insects in that
they are freeze tolerant, but with high lower lethal temperatures. In contrast, Palirhoeus eatoni, a supra-littoral species, avoided freezing and had a mean supercooling point of −15.5 ± 0.94°C (SE) in winter and −11.8 ± 0.98°C
in summer. Survival of a constant low temperature of −8°C also increased in this species from 6 h in summer to 27 h in winter.
It is suggested that this strategy may be a consequence of the osmoregulatory requirements imposed on this species by its
supra-littoral habitat. Upper lethal temperatures (31–34°C) corresponded closely with maximum microclimate temperatures in
all of the species. This indicates that the pronounced warming, accompanied by the increased insolation that has been recorded
at Marion Island, may reduce survival of these species. These effects may be compounded as a consequence of predation by feral
house mice on the weevils.
Received: 4 February 1997 / Accepted: 3 May 1997 相似文献
19.
A heat shock following electroporation induces highly efficient transformation of Corynebacterium glutamicum with xenogeneic plasmid DNA 总被引:10,自引:0,他引:10
An improved method for the electrotransformation of wild-type Corynebacterium glutamicum (ATCC 13032) is described. The two crucial alterations to previously developed methods are: cultivation of cells used for
electrotransformation at 18 °C instead of 30 °C, and application of a heat shock immediately following electrotransformation.
Cells cultivated at sub optimal temperature have a 100-fold improved transformation efficiency (108 cfu μg−1) for syngeneic DNA (DNA isolated from the same species). A heat shock applied to these cells following electroporation improved
the transformation efficiency for xenogeneic DNA (DNA isolated from a different species). In combination, low cultivation
temperature and heat shock act synergistically and increased the transformation efficiency by four orders of magnitude to
2.5 × 106 cfu μg−1 xenogeneic DNA. The method was used to generate gene disruptions in C. glutamicum.
Received: 26 March 1999 / Received revision: 9 June 1999 / Accepted: 11 June 1999 相似文献
20.
Thermal acclimation of locomotor performance in tadpoles of the frog Limnodynastes peronii 总被引:3,自引:0,他引:3
R. S. Wilson C. E. Franklin 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1999,169(6):445-451
Previous analyses of thermal acclimation of locomotor performance in amphibians have only examined the adult life history
stage and indicate that the locomotor system is unable to undergo acclimatory changes to temperature. In this study, we examined
the ability of tadpoles of the striped marsh frog (Limnodynastes peronii) to acclimate their locomotor system by exposing them to either 10 °C or 24 °C for 6 weeks and testing their burst swimming
performance at 10, 24, and 34 °C. At the test temperature of 10 °C, maximum velocity (Umax) of the 10 °C-acclimated tadpoles was 47% greater and maximum acceleration (Amax) 53% greater than the 24 °C-acclimated animals. At 24 °C, Umax was 16% greater in the 10 °C-acclimation group, while there was no significant difference in Amax or the time taken to reach Umax (T-Umax). At 34 °C, there was no difference between the acclimation groups in either Umax or Amax, however T-Umax was 36% faster in the 24 °C-acclimation group. This is the first study to report an amphibian (larva or adult) possessing
the capacity to compensate for cool temperatures by thermal acclimation of locomotor performance. To determine whether acclimation
period affected the magnitude of the acclimatory response, we also acclimated tadpoles of L. peronii to 10 °C for 8 months and compared their swimming performance with tadpoles acclimated to 10 °C for 6 weeks. At the test
temperatures of 24 °C and 34 °C, Umax and Amax were significantly slower in the tadpoles acclimated to 10 °C for 8 months. At 10 °C, T-Umax was 40% faster in the 8-month group, while there were no differences in either Umax or Amax. Although locomotor performance was enhanced at 10 °C by a longer acclimation period, this was at the expense of performance
at higher temperatures.
Accepted: 25 June 1999 相似文献