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Cold Shock (cold + shock)
Terms modified by Cold Shock Selected AbstractsOpposing clines for high and low temperature resistance in Drosophila melanogasterECOLOGY LETTERS, Issue 5 2002Ary A. Hoffmann Abstract In insects, species comparisons suggest a weak association between upper thermal limits and latitude in contrast to a stronger association for lower limits. To compare this to latitudinal patterns of thermal responses within species, we considered latitudinal variation in heat and cold resistance in Drosophila melanogaster. We found opposing clines in resistance to these temperature extremes in comparisons of 17,24 populations from coastal eastern Australia. Knockdown time following heat shock increased towards the tropics, whereas recovery time following cold shock decreased towards temperate latitudes. Mortality following cold shock also showed a clinal pattern. Clinal associations with latitude were linear and related to minimum temperatures in the coldest month (for cold resistance) and maximum temperatures in the warmest month (for heat resistance). This suggests that within species both high and low temperature responses can vary with latitude as a consequence of direct or indirect effects of selection. [source] Cross-generation effects due to cold exposure in Drosophila serrataFUNCTIONAL ECOLOGY, Issue 5 2003A. Magiafoglou Summary 1Environmental variation experienced in the parental and grandparental generation can affect progeny phenotype, performance and response to selection. Here the effects of parental and grandparental exposure to a non-lethal cold shock are considered in Drosophila serrata Malloch. Development time, viability and early age productivity were measured in flies originating from border and central locations in the distribution of this species that had been held under two separate laboratory maintenance schedules. 2Cross-generation effects were detected for several traits. Development time usually decreased following maternal and/or grandmaternal cold exposure. Parental cold exposure negatively influenced viability while grandparental effects on viability were negligible. Early female productivity showed opposing responses depending on generation; maternal cold exposure increased progeny productivity while grandmaternal exposure decreased it. Male parental and grandparental exposure to cold shock decreased male productivity, although this pattern may have been partly confounded by size effects. 3Population effects, reflecting geographical origin, were limited to development time, while selective background effects were demonstrated for most traits. The influence these factors had on the expression of cross-generation effects was negligible, given interactions with treatment were not evident. These responses suggest that environmental variation experienced in preceding generations can influence progeny phenotype in a manner that is complex and difficult to predict. [source] Induction of CspA, an E. coli major cold-shock protein, upon nutritional upshift at 37,°CGENES TO CELLS, Issue 4 2001Kunitoshi Yamanaka Background The synthesis of CspA, the major cold-shock protein of Escherichia coli, is dramatically induced upon cold shock. It was recently reported that there is massive presence of CspA under nonstress conditions, and it is thus claimed that CspA as the cold-shock protein is a misnomer. Results Here, we re-examined and confirmed that CspA is induced upon culture dilution at 37 °C. However, its induction level is one-sixth of the cold-shock-induced level, clearly indicating that the major stress that induces CspA is cold shock. It was further found that CspA induction can be achieved not only by culture dilution but also by the simple addition of nutrients, and that it was almost completely abolished in the presence of rifampicin or nalidixic acid. Nutritional upshift causes the induction of only CspA but not other cold-shock-inducible CspA homologues. The amount of cspA mRNA rapidly and transiently increased by culture dilution, but its stability was not significantly changed. Conclusions These results suggest that CspA is a nutritional-upshift stress protein as well as a cold-shock stress protein, and that CspA induction following nutritional upshift may be due to transcriptional activation. [source] Antibiotics, arsenate and H2O2 induce the promoter of Staphylococcus aureus cspC gene more strongly than coldJOURNAL OF BASIC MICROBIOLOGY, Issue 2 2009Palas Kumar Chanda Abstract Proteins expressed by the bacterial cold shock genes are highly conserved at sequence level and perform various biological functions in both the cold-stressed and normal cells. To study the effects of various agents on the cold shock genes of Staphylococcus aureus, we have cloned the upstream region of cspC from S. aureus Newman and found that the above region possesses appreciable promoter (Pc) activity even at 37 °C. A reporter S. aureus strain CHANDA2, constructed by inserting the Pc - lacZ transcriptional fusion into S. aureus RN4220 genome, was found to express very low level of , -galactosidase after cold shock, indicating that low temperature induces Pc very weakly. Interestingly, transcription from Pc was induced very strongly by several antibiotics, hydrogen peroxide and arsenate salt. Cold shock proteins expressed by S. aureus are highly identical at sequence level and bear single-strand nucleic acid binding motifs. A 16 nt downstream box and a 13 nt upstream box were identified at the downstream of initiation codon and at the upstream of ribosome binding site of csp transcripts. Their roles in S. aureus cold shock gene expression have been discussed elaborately. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Correlated responses to selection for stress resistance and longevity in a laboratory population of Drosophila melanogasterJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 4 2005O. A. BUBLIY Abstract Laboratory studies on Drosophila have revealed that resistance to one environmental stress often correlates with resistance to other stresses. There is also evidence on genetic correlations between stress resistance, longevity and other fitness-related traits. The present work investigates these associations using artificial selection in Drosophila melanogaster. Adult flies were selected for increased survival after severe cold, heat, desiccation and starvation stresses as well as increased heat-knockdown time and lifespan (CS, HS, DS, SS, KS and LS line sets, respectively). The number of selection generations was 11 for LS, 27 for SS and 21 for other lines, with selection intensity being around 0.80. For each set of lines, the five stress-resistance parameters mentioned above as well as longevity (in a nonstressful environment) were estimated. In addition, preadult developmental time, early age productivity and thorax length were examined in all lines reared under nonstressful conditions. Comparing the selection lines with unselected control revealed clear-cut direct selection responses for the stress-resistance traits. Starvation resistance increased as correlated response in all sets of selection lines, with the exception of HS. Positive correlated responses were also found for survival after cold shock (HS and DS) and heat shock (KS and DS). With regard to values of resistance across different stress assays, the HS and KS lines were most similar. The resistance values of the SS lines were close to those of the LS lines and tended to be the lowest among all selection lines. Developmental time was extended in the SS and KS lines, whereas the LS lines showed a reduction in thorax length. The results indicate a possibility of different multiple-stress-resistance mechanisms for the examined traits and fitness costs associated with stress resistance and longevity. [source] Effects of 2-hydroxypropyl-,-cyclodextrin and cholesterol on porcine sperm viability and capacitation status following cold shock or incubationMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 5 2006Hannah L. Galantino-Homer Abstract Porcine sperm are extremely sensitive to the damaging effects of cold shock. It has been shown that cholesterol-binding molecules, such as 2-hydroxypropyl-,-cyclodextrin (HBCD), improve post-cooling porcine sperm viability when added to an egg yolk-based extender, but also enhance sperm capacitation in other species. The objective of this study was to determine the effects of HBCD and cholesterol 3-sulfate (ChS) on porcine sperm viability and capacitation following cold shock or incubation under conditions that support capacitation using a defined medium. We report here that porcine sperm incubated in medium containing both HBCD and ChS have significantly improved viability following cold shock (10 min at 10°C) when compared to sperm incubated without HBCD or ChS, or with either component alone. Treatment with HBCD plus ChS also completely inhibited the increase in protein tyrosine phosphorylation induced by the cold shock treatment or by incubation for 3 hr under conditions that support capacitation. Two assays of sperm capacitation, the rate of calcium ionophore-induced acrosome reactions and chlortetracycline (CTC) staining, were not significantly altered by HBCD and ChS following cold shock. However, 3-hr incubation with HBCD plus ChS or with 1 mM ChS alone decreased the percentage of sperm undergoing the induced acrosome reaction without significantly affecting viability when compared to the control. These results indicate that the manipulation of sperm plasma membrane cholesterol content affects porcine sperm viability and capacitation status and could therefore be useful to protect sperm from cold shock during cryopreservation by improving viability without promoting premature capacitation. Mol. Reprod. Dev. © 2006 Wiley-Liss, Inc. [source] Influence of Ovulation Status, Seasonality and Embryo Transfer Method on Development of Cloned Porcine EmbryosREPRODUCTION IN DOMESTIC ANIMALS, Issue 5 2010OJ Koo Contents To improve pig cloning efficiency, the present study evaluated the effect of ovulation status, seasonality and embryo transfer (ET) method on in vivo development of cloned porcine embryos. Cloned embryos were transferred to surrogate mothers on the same day of somatic cell nuclear transfer. In pre-ovulation stage (PO), pregnancy rate (PR) and delivery rate (DR) were 36.3% and 9.4%, respectively. In post-ovulation stage, 22.7% PR and 2.1% DR were recorded (both PR and DR are significantly higher in PO). When ET was performed during winter (December,February), spring (March,May), summer (June,August) and autumn (September,November), the PRs were 13.4%, 37.3%, 24.6% and 51.0%, while DRs were 0%, 12.7%, 4.3% and 7.8%, respectively. The highest PRs were recorded in autumn groups. However, DRs were significantly lower in autumn (7.8%) group compared with spring (12.7%) group. The PR was the lowest and no piglets were born in winter group, which might be because of the effect of low temperature during ET. To overcome the low PR in winter group, 0.25 ml straws were used for ET to minimize exposure time of embryos to ambient temperature. The straw ET group showed significantly higher PR in the winter group (23. 9%) compared with the conventional catheter-loading group (7.7%). We suggest that using PO recipient and ET in spring is the best condition for pig cloning. In addition, alternative method to reduce cold shock during ET in winter is necessary. [source] Cold-inducible zinc finger-containing glycine-rich RNA-binding protein contributes to the enhancement of freezing tolerance in Arabidopsis thalianaTHE PLANT JOURNAL, Issue 6 2005Yeon-Ok Kim Summary Glycine-rich RNA-binding proteins (GR-RBPs) have been implicated to play roles in post-transcriptional regulation of gene expression in plants under various stress conditions, but the functional roles of GR-RBPs under stress conditions remain to be verified. Here, we examine the biological roles of a GR-RBP, designated atRZ-1a, in Arabidopsis thaliana under stress conditions. atRZ-1a was expressed ubiquitously in various Arabidopsis organs including stems, roots, leaves, flowers, and siliques. The transcript level of atRZ-1a increased markedly by cold stress, whereas its expression was marginally downregulated by drought stress or abscisic acid treatment. Germination and seedling growth of the loss-of-function mutants were retarded remarkably compared with those of the wild type under cold stress. In contrast, the transgenic Arabidopsis plants that overexpress atRZ-1a displayed earlier germination and better seedling growth than the wild type under cold stress. Moreover, the atRZ-1a-overexpressing transgenic Arabidopsis plants were more freezing tolerant than the wild-type plants. Heterologous expression of atRZ-1a in Escherichia coli demonstrated that the E. coli cells expressing atRZ-1a displayed much higher growth rate than the non-transformed cells after cold shock. These results provide evidence that atRZ-1a affects seed germination and seedling growth under low temperature and plays a role in the enhancement of freezing tolerance in Arabidopsis plants. [source] Crystallization and X-ray structure of cold-shock protein E from Salmonella typhimuriumACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 12 2009Hugh P. Morgan In prokaryotic organisms, cold shock triggers the production of a small highly conserved family of cold-shock proteins (CSPs). CSPs have been well studied structurally and functionally in Escherichia coli and Bacillus subtilis, but Salmonella typhimurium CSPs remain relatively uncharacterized. In S. typhimurium, six homologous CSPs have been identified: StCspA,E and StCspH. The crystal structure of cold-shock protein E from S. typhimurium (StCspE) has been determined at 1.1,Å resolution and has an R factor of 0.203 after refinement. The three-dimensional structure is similar to those of previously determined CSPs and is composed of five antiparallel ,-strands forming a classic OB fold/five-stranded ,-barrel. This first structure of a CSP from S. typhimurium provides new insight into the cold-shock response of this bacterium. [source] Artificial gynogenesis in Cynoglossus semilaevis with homologous sperm and its verification using microsatellite markersAQUACULTURE RESEARCH, Issue 6 2010Xiang-Shan Ji Abstract Effective methods for induction of gynogenetic diploids in Cynoglossus semilaevis are needed to initiate monosex culture. An effective protocol to induce half-smooth tongue sole gynogenesis using homologous sperm was developed in this study. A UV dose of 50 mJ cm,2 was found to be the most effective for genetic inactivation of tongue sole sperm. Treatment optima for cold shocks were 5 °C for 20,23 min at 5 min after fertilization and the hatching rate of gynogenetic diploids was 10.0%. Microsatellite analysis at locus Csou 6 revealed that there was no genetic contribution from the paternal genome in 24 progenies of a meiotic gynogenetic family. Polymerase chain reaction demonstrated that only four individuals of 24 meiotic gynogenetic diploids produced the female-specific band of about 205 bp. The female/male ratio of gynogenetic diploids was significantly different from the theoretical ratio of 1:1. It is possible that there are some recessive lethal genes in W chromosome. [source] | ||||||||||||||||||||||