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Freezing sperm is a complex process that can result in various forms of cell damage. Such damage may reduce the motility and fertility of thawed sperm used for artificial insemination. In this study, fifteen semen samples were collected from five mixed-breed male dogs, and each sample was divided into three parts (control, 0.2 mmol vitamin E, and 0.4 mmol vitamin E). Although motility was observed in groups that received antioxidants, this increase was not statistically significant. However, the average motility of high-speed progressive sperm after thawing indicates a significant increase (P≤0.05) in their motility. The study showed a significant increase (P≤0.05) in high-speed progressive sperm motility, VCL, VSL, VAP, and BCF values in groups 0.2 and 0.4 compared to the control group. However, this increase was only observed in the cold shock-resistant group. In the test, the evaluation of the integrity of the sperm membrane in Group 0.4 showed a significant increase (P≤0.05) compared to the control group. The study finds that using vitamin E with concentrations of 0.2 and 0.4 improves the resistance of sperm to shocks compared to sperm that are sensitive to this phenomenon. This positive effect of vitamin E can be attributed to higher levels of unsaturated fatty acids that are susceptible to peroxidation in this group of sperm. [ABSTRACT FROM AUTHOR]

BACKGROUND RESULTS CONCLUSION In order to comprehend the regulatory mechanisms that result in the alleviation of sweet cherry pitting disorder through cold shock (0 °C ice–water mixture for 10 min), an investigation was conducted into the impacts of cold shock treatment (CST) on membrane lipid metabolism, antioxidant enzyme activity, as well as pitting of cold‐stored sweet cherry fruit.CST significantly inhibited the increase in pitting incidence, pitting index, and decay incidence. The CST treatment provided greater titratable acidity, firmness as well as total content of soluble solids. The use of CST prevented the build‐up of superoxide anions, hydrogen peroxide, malondialdehyde, and reduced permeability of cell membranes. When in contrast to control group, the CST also raised the expression levels along with activity of the antioxidant enzymes ascorbate peroxidase (APX), glutathione reductase (GR), superoxide dismutase (SOD), and catalase (CAT). Furthermore, CST reduced the amount of fruit cell membrane peroxidation, suppressed the activity of phospholipase and lipoxygenase, postponed the rise in saturated fatty acids (SFAs) and decrease in unsaturated fatty acids (USFAs), ultimately keeping a high ratio of USFAs to SFAs.CST can alleviating pitting disorder in sweet cherry fruit via preventing peroxidation of membrane lipid and elevating the antioxidant enzymes activity. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Previously, we found for the first time the participation of osmolytes in adaptation to acidic conditions in three acidophilic fungi. Because trehalose can protect membranes, we hypothesized a relationship between osmolyte and membrane systems in adaptation to stressors. In the mycelium of Phlebiopsis gigantea, the level of osmolytes reaches 8% of the dry mass, while trehalose and arabitol make up 60% and 33% of the sum, respectively. Cold shock does not change the composition of osmolytes, heat shock causes a twofold increase in the trehalose level, and osmotic shock leads to a marked increase in the amount of trehalose and arabitol. Predominance of phospholipids (89% of the sum) and low proportions of sterols and sphingolipids are characteristic features of the membrane lipids' composition. Phosphatidic acids, along with phosphatidylethanolamines and phosphatidylcholines, are the main membrane lipids. The composition of the membrane lipids remains constant under all shocks. The predominance of linoleic (75% of the sum) and palmitic (20%) acids in phospholipids results in a high degree of unsaturation (1.5). Minor fluctuations in the fatty acid composition are observed under all shocks. The results demonstrate that maintaining or increasing the trehalose level provides stability in the membrane lipid composition during adaptation. [ABSTRACT FROM AUTHOR]

High hydrostatic pressure processing (HHP) is used to reduce or eliminate pathogens and spoilage bacteria in food. The aim of this study was to investigate the effect of fat on the pressure resistance of E. coli in beef and a yogurt model system. Ground beef and pH-adjusted (pH 5.5) yogurt were adjusted to a fat content from 3 to 35% with adipose tissue and crème fraiche, respectively, and inoculated with E. coli. Samples were treated at 600 MPa and 20 or 30 °C for 3 min. Sample temperatures were adjusted prior to compression to compensate adiabatic heating, or not. An increased fat content of ground beef decreased the pressure resistance of E. coli. This was observed irrespective of the temperature history of the treatment. For example, at 20 °C, an increase in fat content from 15.5 to 24.4% increased treatment lethality by 6 log CFU/g for E. coli MG 1655. The correction for adiabatic heating increased or decreased pressure resistance at 20 °C in a strain-specific manner. Addition of crème fraiche to pH-adjusted yogurt did not alter the pressure resistance of E. coli (strains MG 1655 and DM 18.3), or increased resistance (E. coli AW 1.7 and AW 1.3). In summary, the pressure resistance of E. coli is dependent on the fat content, the food matrix and the temperature trajectory during processing. The effect of adipose tissue in meat matrix links the fat content of meat to lipid oxidation and the oxidative stress response. [ABSTRACT FROM AUTHOR]

During a field study in spring 2022 the goal was to monitor pollinators in underexplored habitats in Eastern Romania, Dobrogea province. Here, also different populations of spring butterflies were observed, including those of the Lesser Spotted Fritillary Melitaea trivia (Denis & Schiffermüller, 1975) (Lepidoptera: Nymphalidae). In the Tulceae area, near Babadag, in broadleaved, deciduous woodland steppe with understorey vegetation and clearings, a rare natural melanistic aberration of a M. trivia male was found. Pictures of the aberration are shown and compared with upper- and undersides of typical wing patterns, and with similar artificial aberrations produced with injections of sodium tungstate in controlled lab conditions. Such aberrant morph types are discussed in relation to cold shock during the pupation stage and compared to melanistic specimens generated under artificially controlled conditions. [ABSTRACT FROM AUTHOR]

Cells are continuously exposed to various sources of insults, among which temperature variations are extremely common. Epigenetic mechanisms, critical players in gene expression regulation, undergo alterations due to these stressors, potentially leading to health issues. Despite the significance of DNA methylation and histone modifications in gene expression regulation, their changes following heat and cold shock in human cells remain poorly understood. In this study, we investigated the epigenetic profiles of human cells subjected to hyperthermia and hypothermia, revealing significant variations. Heat shock primarily led to DNA methylation increments and epigenetic modifications associated with gene expression silencing. In contrast, cold shock presented a complex scenario, with both methylation and demethylation levels increasing, indicating different epigenetic responses to the opposite thermal stresses. These temperature-induced alterations in the epigenome, particularly their impact on chromatin structural organization, represent an understudied area that could offer important insights into genome function and potential prospects for therapeutic targets.

Aim: Study of HSPs synthesis after heat and cold shock and explanation of thermotolerance by the transport of HSPs to the plasma membrane. Methods and Results: Physical (cold and heat shock) and chemical (lignocaine) damage to plasma membrane was achieved in thermotolerant and mesophilic strains of Saccharomyces cerevisiae. In shocked yeasts K+ ion efflux, leakage of UV280 absorbing material, HSP expression profile and viability at 25 and 45°C were studied. Physical/chemical shock was given for 30 minutes and subsequently yeasts were incubated at 25°C to avoid further membrane damage by stress. In thermotolerant strain, membrane damage increased up to 70 minutes (30 min of shock and 40 min at 25°C) and reduced thereafter. De-novo HSPs in membrane were noted at 60 minutes and reached maximum at 80 minutes in thermotolerant strain. In mesophilic yeast, de-novo HSPs were not synthesized and leakage was continuous up to the studied period (100 minutes). Conclusion: These de-novo HSPs are transported to the membrane for restoring the membrane integrity and to prevent the leakage. The thermotolerant strain can grow at higher temperatures compared to mesophilic strain due to more production of HSPs and HSP associated membrane damage reversal. Significance and Impact of the Study: Several reports established the role of HSPs in thermotolerance but their mode of action is not well characterized. The current method explains the mechanism for acquiring thermotolerance in yeast.

ABSTRACTFacing rapid fluctuations in their natural environment, extremophiles, like the hyperthermophilic archaeon Pyrococcus furiosus, exhibit remarkable adaptability to extreme conditions. However, our understanding of their dynamic cellular responses remains limited. This study integrates RNA-sequencing and mass spectrometry data, thereby elucidating transcriptomic and proteomic responses to heat and cold shock stress in P. furiosus. Our results reveal rapid and dynamic changes in gene and protein expression following these stress responses. Heat shock triggers extensive transcriptome reprogramming, orchestrated by the transcriptional regulator Phr, targeting a broader gene repertoire than previously demonstrated. For heat shock signature genes, RNA levels swiftly return to baseline upon recovery, while protein levels remain persistently upregulated, reflecting a rapid but sustained response. Intriguingly, cold shock at 4°C elicits distinct short- and long-term responses at both RNA and protein levels. Cluster analysis identified gene sets with either congruent or contrasting trends in RNA and protein changes, representing well-separated arCOG groups tailored to their individual cellular responses. Particularly, upregulation of ribosomal proteins and significant enrichment of 5′-leadered sequences in cold-shock responsive genes suggest that translation regulation is important during cold shock adaption. Further investigating transcriptomic features, we reveal that thermal stress genes are equipped with basal sequence elements, such as strong promoter and poly(U)-terminators, facilitating a regulated response of the respective transcription units. Our study provides a comprehensive overview of the cellular response to temperature stress, advancing our understanding of stress response mechanisms in hyperthermophilic archaea and providing valuable insights into the molecular adaptations that facilitate life in extreme environments.IMPORTANCEExtreme environments provide unique challenges for life, and the study of extremophiles can shed light on the mechanisms of adaptation to such conditions. Pyrococcus furiosus, a hyperthermophilic archaeon, is a model organism for studying thermal stress response mechanisms. In this study, we used an integrated analysis of RNA-sequencing and mass spectrometry data to investigate the transcriptomic and proteomic responses of P. furiosus to heat and cold shock stress and recovery. Our results reveal the rapid and dynamic changes in gene and protein expression patterns associated with these stress responses, as well as the coordinated regulation of different gene sets in response to different stressors. These findings provide valuable insights into the molecular adaptations that facilitate life in extreme environments and advance our understanding of stress response mechanisms in hyperthermophilic archaea.

This study assessed the effectiveness of triploidy in tambaqui (Colossoma macropomum) and compared the fertilization, survival, growth performance, and hematological parameters of diploid and triploid fish. After artificial reproduction, freshly fertilized eggs were subjected to cold, heat or double thermal shock or were not exposed to the thermal shock (control group). Double thermal shock presented fertilization rate significantly lower than other treatments. Larvae submitted to cold thermal shock had a higher weight than the control and heat thermal shock treatments. The final weight of juveniles exposed to cold thermal shock was significantly higher than the other treatments with triploid induction. There was no significant difference for survival and hematological variables. The cold thermal shock produced more triploid individuals (33.33%) than the heat and double thermal shock (both 11.11%). The cold thermal shock was the most effective technique for obtaining triploid fish and it contributed to increasing the weight of tambaqui larvae. [ABSTRACT FROM AUTHOR]

The article presents the results of a study of some adaptive properties of a bacterial isolate from wheat bran, identified by the 16S rRNA gene as an Arthrobacter agilis strain. According to the literature data, A. agilis does not belong to the dominant bacterial species of wheat microbial associations and activates growth at low ambient temperatures. The studied A. agilis strain showed poor growth in a microbial consortium when an aqueous suspension of wheat bran, partially fermented at 28 ± 1°C by the native microbiota, was plated on a dense MPA medium and produced the pigment after three weeks of storage at 4 ± 1°C. Moderate growth of bacteria without increased pigmentation was observed during its subsequent transfer after low-temperature storage on agar media containing carbohydrates and nitrogen compounds, mineral salts, and vitamins that were more easily utilized than native bran. The growth of colonies upon plating on such media increased in the series: thermally fermented wheat bran → HMF agar → LB (without salt). It was revealed that the A. agilis strain, which was not typical of the wheat bran microflora, under the influence of osmotic and/or temperature shock (in response to a sharp change in the NaCl concentration and/or a difference in ambient temperatures) produced pigments both in agar and liquid cultures. According to the results of spectral analysis, the pigment was assigned to carotenoids and tentatively identified as bacterioruberin. Quantitative evaluation showed that, under stress conditions during submerged cultivation, the studied strain A. agilis wb28 was able to synthesize the pigment at the level of 52.8 mg/L (17.2 mg/g biomass). [ABSTRACT FROM AUTHOR]

Aims: Rhodotorula sp. (USM-PSY62) is a psychrophilic yeast isolated from Antarctic sea ice that grows optimally at 15 °C. The inevitable global warming poses many challenges to the microbial community in Antarctica. Therefore, this study was conceptualized to observe how USM-PSY62 adapted to fluctuations in temperature. Methodology and results: Rhodotorula sp. (USM-PSY62) was grown in YPD broth until the mid-log phase. Then, the culture was transferred to four different temperatures, specifically at 0 °C, 5 °C, 15 °C and 21 °C for 24 h. Then, the RNA was extracted, sequenced and analysed. During cold adaptation, an elevated transcription of the CorA magnesium transporter gene in USM-PSY62 indicated a higher requirement for magnesium ions to gain additional enzyme cofactors or maintain cytoplasmic fluidity. The HepA homologue coding for DNA/RNA helicase was also over-expressed with log fold change 2.89 in cold conditions possibly to reorganize secondary structures of DNA and RNA. An up-regulation of the catalase gene was also observed, reflecting an increment in the concentration of reactive oxygen species and fluctuations in the associated antioxidant system. The YOP1 gene, which encodes a membrane protein associated with protein transport and membrane traffic, was the most down-regulated, with log2 fold change values of -6.93 lower under cold shock conditions. The genes responsible for the structural maintenance of chromosome (SMC) have a -8.80 in expression log2 fold change, indicating the gene was down-regulated when the temperature was shifted to 0 °C. Upon cold shock, the gene for heat shock factor protein 1 (HSF1) was also down-regulated with a log2 fold change value of - 5.86. Hsf1 is a transcriptional regulator which regulates the heat shock responses. Conclusion, significance and impact of study: In conclusion, the transcriptomic responses demonstrated by Rhodotorula sp. USM-PSY62 characterized critical physiological and biochemical compensatory mechanisms especially cellular processes and signalling, information storage and processing, and metabolism to survive at low and high temperatures. This study provides valuable data for industry, especially in the usage of molecular chaperones. [ABSTRACT FROM AUTHOR]

Colder water temperatures are generally regarded as a stressful period for fishes (i.e., winter stress syndrome), which can be exacerbated by cold‐shock stress associated with major arctic freezes. Although cold‐shock stress and mass mortalities are well documented for coastal marine fishes, few studies report the effects of winter stress or cold‐shock stress on inland fishes. The purposes of this study were to describe patterns in inland fish mortalities associated with winter stress syndrome and with cold‐shock stress in Texas as a regional example of inland fish mortalities associated with colder water temperatures. Using fish mortality reports (1969–2021) recorded by state agency biologists, colder water temperature mortalities occurred in 66% (N = 35) of the years, with greatest percentages of the reports occurring during three major arctic freezes in 1981, 1983 and 2021. The majority of reports were from urbanized counties (79%) and from lentic habitats (56%). Seventeen taxa and 1,021,217 individuals were estimated to be killed during the 53s years. Numbers of inland fish mortalities were greater during major arctic freeze years than non‐major arctic freeze years, attributed primarily to mortalities of non‐native fishes (e.g., blue tilapia Oreochromis aureus, suckermouth catfish Hypostomus plecostomus). Numbers of native fish mortalities, primarily clupeids and catostomids, were not different between major arctic freeze years and non‐major arctic freezes. The 43,000 inland fish mortalities reported during major arctic freeze years are in stark contrast to the 35 million coastal marine fish mortalities. Proposed mechanisms to explain cold‐shock mortalities in coastal waters (e.g., species within the northern extent of their range, lack of access to deeper water) are similar in inland waters, yet inland waters do not have the same level of mortalities. Consequently, the disparities between mortalities in coastal and inland waters are not readily discernable at this time. [ABSTRACT FROM AUTHOR]

Previously, we found for the first time the participation of osmolytes in adaptation to acidic conditions in three acidophilic fungi. Because trehalose can protect membranes, we hypothesized a relationship between osmolyte and membrane systems in adaptation to stressors. In the mycelium of Phlebiopsis gigantea, the level of osmolytes reaches 8% of the dry mass, while trehalose and arabitol make up 60% and 33% of the sum, respectively. Cold shock does not change the composition of osmolytes, heat shock causes a twofold increase in the trehalose level, and osmotic shock leads to a marked increase in the amount of trehalose and arabitol. Predominance of phospholipids (89% of the sum) and low proportions of sterols and sphingolipids are characteristic features of the membrane lipids’ composition. Phosphatidic acids, along with phosphatidylethanolamines and phosphatidylcholines, are the main membrane lipids. The composition of the membrane lipids remains constant under all shocks. The predominance of linoleic (75% of the sum) and palmitic (20%) acids in phospholipids results in a high degree of unsaturation (1.5). Minor fluctuations in the fatty acid composition are observed under all shocks. The results demonstrate that maintaining or increasing the trehalose level provides stability in the membrane lipid composition during adaptation.

AtGRP2 (Arabidopsis thaliana glycine-rich protein 2) is a 19-kDa RNA-binding glycine-rich protein that regulates key processes in A. thaliana. AtGRP2 is a nucleo-cytoplasmic protein with preferential expression in developing tissues, such as meristems, carpels, anthers, and embryos. AtGRP2 knockdown leads to an early flowering phenotype. In addition, AtGRP2-silenced plants exhibit a reduced number of stamens and abnormal development of embryos and seeds, suggesting its involvement in plant development. AtGRP2 expression is highly induced by cold and abiotic stresses, such as high salinity. Moreover, AtGRP2 promotes double-stranded DNA/RNA denaturation, indicating its role as an RNA chaperone during cold acclimation. AtGRP2 is composed of an N-terminal cold shock domain (CSD) followed by a C-terminal flexible region containing two CCHC-type zinc fingers interspersed with glycine-rich sequences. Despite its functional relevance in flowering time regulation and cold adaptation, the molecular mechanisms employed by AtGRP2 are largely unknown. To date, there is no structural information regarding AtGRP2 in the literature. Here, we report the 1H, 15N, and 13C backbone and side chain resonance assignments, as well as the chemical shift-derived secondary structure propensities, of the N-terminal cold shock domain of AtGRP2, encompassing residues 1–90. These data provide a framework for AtGRP2-CSD three-dimensional structure, dynamics, and RNA binding specificity investigation, which will shed light on its mechanism of action. [ABSTRACT FROM AUTHOR]

The in vitro effect of cold shock on nucleated erythrocytes of the benthic scorpionfish Scorpaena porcus L. was studied. Blood samples were exposed to 22°C (control group) and 4°C (experimental group) for 3 h. Cold shock had no significant impact on vital characteristics of scorpionfish erythrocytes. The cells retained the integrity of cytoplasmic membranes, mitochondrial potential, and levels of oxidative processes, as evidenced by constant values of propidium iodide, rhodamine 123, and 2',7'-dichlorodihydrofluorescein diacetate fluorescence intensity. Main changes were concerned with erythrocyte shape and nucleus functional activity. While the red blood cells became more rounded, the nucleus size increased, leading to a higher nuclear–cytoplasmic ratio and a decrease in the fluorescence intensity of cells labeled with a nuclear dye SYBR Green I. Supposedly, this was due to cytoskeletal alterations and activation of transcriptional processes. [ABSTRACT FROM AUTHOR]

Aim: Study of HSPs synthesis after heat and cold shock and explanation of thermotolerance by the transport of HSPs to the plasma membrane. Methods and Results: Physical (cold and heat shock) and chemical (lignocaine) damage to plasma membrane was achieved in thermotolerant and mesophilic strains of Saccharomyces cerevisiae. In shocked yeasts K+ ion efflux, leakage of UV280 absorbing material, HSP expression profile and viability at 25 and 45°C were studied. Physical/chemical shock was given for 30 minutes and subsequently yeasts were incubated at 25°C to avoid further membrane damage by stress. In thermotolerant strain, membrane damage increased up to 70 minutes (30 min of shock and 40 min at 25°C) and reduced thereafter. De-novo HSPs in membrane were noted at 60 minutes and reached maximum at 80 minutes in thermotolerant strain. In mesophilic yeast, de-novo HSPs were not synthesized and leakage was continuous up to the studied period (100 minutes). Conclusion: These de-novo HSPs are transported to the membrane for restoring the membrane integrity and to prevent the leakage. The thermotolerant strain can grow at higher temperatures compared to mesophilic strain due to more production of HSPs and HSP associated membrane damage reversal. Significance and Impact of the Study: Several reports established the role of HSPs in thermotolerance but their mode of action is not well characterized. The current method explains the mechanism for acquiring thermotolerance in yeast. [ABSTRACT FROM AUTHOR]

Temperature is one of the most important factors in all living organisms for survival. Being a unicellular organism, bacterium requires sensitive sensing and defense mechanisms to tolerate changes in temperature. During a temperature shift, the structure and composition of various cellular molecules including nucleic acids, proteins, and membranes are affected. In addition, numerous genes are induced during heat or cold shocks to overcome the cellular stresses, which are known as heat- and cold-shock proteins. In this review, we describe the cellular phenomena that occur with temperature change and bacterial responses from a molecular perspective, mainly in Escherichia coli. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Hydrobiology is the property of Editorial Department of Journal of Hydrobiology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Nowadays, many boar reproduction researches are directed to improve extenders and to increase cold shock protection of semen. Little research is focused on the influence of egg yolk combined with alternative cold shock protective media. Egg yolk could interfere with other compounds present in the extender composition. The influence of egg yolk addition was assessed in boar sperm cells, cooled at 5ºC, to elucidate its effect on motility and membrane integrity. Flow Cytometry and Computer Assisted Semen Analysis (CASA) were used to determine the rate of sperm with intact plasma and acrosomal membrane, respectively the sperm cells motility. Statistical analyses (T-Test) were performed using GraphPad Prism version 5.00. Androhep Plus supplemented with 20% egg yolk (AhPlus+20%EY) indicated a higher cold shock protection in progressive motility (93.9±2.64%) and membrane integrity (79.78±4.14%), rather than the extender without egg yolk (p0.05). The combination egg yolk-AhPlus seems to be an alternative to standard extenders, conferring stability in boar sperm cells against cold shock.

In this study, the cold shock treatment was used to induce triploid yellow drum (Nibea albiflora) and the ploidy was determined. The histology and gene expression analysis of reproduction-related genes were further used to characterize the gonadal development in triploid yellow drum. Firstly, the fertilized eggs were subjected to the cold shock treatment implemented at 3 °C for a period of 10 min commencing at post-fertilization 2.5min, and the fertilization rate and hatching rate in the cold shock treatment groups were (70.31±4.49)% and (21.5±6.63)%, respectively, which were significantly lower than that of diploid. Secondly, we found that the DNA relative content of triploid was 1.5 times larger than that of diploid by flow cytometer analysis, and the number of the chromosome in the triploid was 72, whereas the number of the chromosome in the diploid was 48 shown by karyotype analysis. The rate of the triploid was 100% in the present study. Thirdly, the gonadosomatic indexes of the triploids were significantly lower than that of the diploids. Histological results showed that the gonadal development of the triploids was slower than that of the diploids. At the age of 12 months, the testis and ovary of the diploids were both at the stage V, while the testis and ovary of the triploids were at stage III and stage I, respectively. Fourthly, the dmrt1 and vasa expression in the triploid testis and cyp19a expression in the triploid ovary were significantly lower than those in the diploid gonads (P<0.05), and the vasa expression in the triploid ovary was also lower than that in the diploids (P>0.05). The results indicated that the triploid yellow drum could be successfully induced by the cold shock treatment, and the gonadal development of the triploids was retarded. The results of present study will lay a basis for the application of the triploid in germ cell transplantation and the genetic improvement of yellow drum. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Hydrobiology is the property of Editorial Department of Journal of Hydrobiology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The application of cold shock to inhibit the extrusion of the second polar body in fertilized eggs is one of the main methods to induce triploid in diploid fish. In this study, we originally planned to induce hexaploid by this method in tetraploid carp. However, among the surviving offspring, we observed only 50.7% tetraploid and 49.3% diploid individuals, which could potentially result from either androgenetic diploids or gynogenetic diploids. The absence of irradiation and the high proportion of diploids attracted us. However, the lack of sex-specific markers for tetraploid carp, makes it difficult to determine their origin. Fortunately, we also carried out the cross of yellow carp (Cyprinus carpio yellow var., 2n, ♀) × tetraploid carp (♂) and red crucian carp (Carassius auratus red var., 2n, ♀) × tetraploid carp (♂) with cold shock inhibiting the second meiosis, diploid offspring have also been found, and whether they have undergone gynogenesis or androgenesis can be judged based on phenotype and genotype. In terms of phenotypes, the key phenotypes of two diploids, such as the whisker length, number of lateral scales, and presence of melanin, are consistent with tetraploid carp. In terms of genotypes, through single-copy nuclear gene cloning and fluorescence in situ hybridization (FISH), it is supported that both diploids are androgenetic offspring. In addition, 14.9% of tetraploid offspring were found in red crucian carp (♀) × tetraploid carp (♂) with cold shock inhibiting the second meiosis. By the above-mentioned means of detection, it was found that they were created by inhibiting the extrusion of the second polar body of the fertilized eggs. From this it will be seen that the application of cold shock before the extrusion of the second polar body of fertilized eggs cause not only polyploidy, but also the elimination of both second polar body and female nucleus. Previous studies have found that cold shock can induce lethal androgenetic haploids in diploid fish, but these androgenetic diploid fish produced by tetraploid carp sperm were surviving. We summarize the mechanism behind the above phenomenon, which is mainly related to meiosis occurring at the edge of the cell membrane. Cold shock may disrupt the function of the spindle, resulting in the simultaneous retention or extrusion of female nucleus and second polar body. This study will provide valuable insights into androgenesis, polyploidization, and hybridization in fish genetic breeding. • Androgenetic diploids were induced from tetraploid carp sperm by cold shock without irradiating the eggs. • New-type allotetraploids were induced in the cross between male tetraploid carp and female diploid carp by cold shock. • Nuclear gene cloning is suitable for qualitative analysis of the genetic composition of hybrids, but not for quantitative analysis. [ABSTRACT FROM AUTHOR]

Temperature influences the structural and functional properties of cellular components, necessitating stress responses to restore homeostasis following temperature shift. Whereas the circuitry controlling the heat shock response is well understood, that controlling the E. coli cold shock adaptation program is not. We found that during the growth arrest phase (acclimation) that follows shift to low temperature, protein synthesis increases, and open reading frame (ORF)-wide mRNA secondary structure decreases. To identify the regulatory system controlling this process, we screened for players required for increased translation. We identified a two-member mRNA surveillance system that enables recovery of translation during acclimation: RNase R assures appropriate mRNA degradation and the Csps dynamically adjust mRNA secondary structure to globally modulate protein expression level. An autoregulatory switch in which Csps tune their own expression to cellular demand enables dynamic control of global translation. The universality of Csps in bacteria suggests broad utilization of this control mechanism.

Seawater temperatures have increased with global climate change. Coolant water discharged from coastal nuclear power-generating and coal-powered plants, coupled with already increasing seawater temperatures, can adversely affect local fish communities. A sudden drop in temperature caused by the winter shutdown of power plants can also affect fish health and behavior. To assess the effects of temperature change on fish populations, we subjected early life stages of the once commercially important large yellow croaker (Larimichthys crocea) to various water temperature experiments. Fertilized eggs showed the highest hatching rate at 23.4°C and the lowest rate of deformity in hatched larvae at 23.0°C. We determined the incipient lethal temperature for each life stages using derivation models. Ranges between the upper and lower incipient lethal temperatures increased during development from yolk-sac larvae to juveniles, especially in response to cold shock, indicating that later developmental stages in this species are more tolerant of temperature fluctuations. However, thermal tolerance is not solely determined by life stage. Our results suggest that rapid changes in seawater temperature caused by power plant coolant water discharges may significantly affect early developmental stages of fish. Critical thermal maximum tests indicate that the seawater heating rate is significantly negatively correlated with survival time and affects the critical thermal maximum value of L. crocea. On the basis of our determination of incipient lethal temperatures, emergency measures could be taken to avoid adverse economic and ecological impacts due to changes in seawater temperature caused by coolant water discharges.

One of the advantages of using epididymal sperm is helping to preserve the genetic resources of elite animals and endangered species after death. This study aimed to investigate the probable protective effect of polyvinyl alcohol (PVA) and polyethylene glycol (PEG) on epididymal ram sperm under liquid storage at 4 ° C for 24 hours. Sperms were collected by making an incision on the epididymis of slaughtered rams and extended in extenders supplemented with 0 (control), 0.5, 1, 2, 5 and 10 mg/ml polyvinyl alcohol or polyethylene glycol then refrigerated for 24 hours. We found that only 0.5 mg/ml of PVA group had higher motility parameters comparing to control group (P <0.05). The lowest motility in PVA groups was observed at the concentration of 10 mg/ml. Extenders supplemented with PEG in different concentrations had no significant effect on the most kinetic indices. Both compounds were lethal to sperm at 15 mg/ml. [ABSTRACT FROM AUTHOR]

Stress response helps microorganisms survive extreme environmental conditions and host immunity, making them more virulent or drug resistant. Although both reductionist approaches investigating specific genes and systems approaches analyzing individual stress conditions are being used, less is known about gene networks involved in multiple stress responses. Here, using a systems biology approach, we mined hundreds of transcriptomic data sets for key genes and pathways involved in the tolerance of the model microorganism Escherichia coli to multiple stressors. Specifically, we investigated the E. coli K-12 MG1655 transcriptome under five stresses: heat, cold, oxidative stress, nitrosative stress, and antibiotic treatment. Overlaps of transcriptional changes between studies of each stress factor and between different stressors were determined: energy-requiring metabolic pathways, transport, and motility are typically downregulated to conserve energy, while genes related to survival, bona fide stress response, biofilm formation, and DNA repair are mainly upregulated. The transcription of 15 genes with uncharacterized functions is higher in response to multiple stressors, which suggests they may play pivotal roles in stress response. In conclusion, using rank normalization of transcriptomic data, we identified a set of E. coli stress response genes and pathways, which could be potential targets to overcome antibiotic tolerance or multidrug resistance. [ABSTRACT FROM AUTHOR]

Memories are lasting representations over time of associations between stimuli or events. In general, the relatively slow consolidation of memories requires protein synthesis with a known exception being the so-called Anesthesia Resistant Memory (ARM) in Drosophila. This protein synthesis-independent memory type survives amnestic shocks after a short, sensitive window post training, and can also emerge after repeated cycles of training in a negatively reinforced olfactory conditioning task, without rest between cycles (massed conditioning—MC). We discussed operational and molecular mechanisms that mediate ARM and differentiate it from protein synthesis-dependent long-term memory (LTM) in Drosophila. Based on the notion that ARM is unlikely to specifically characterize Drosophila, we examined protein synthesis and MC-elicited memories in other species and based on intraspecies shared molecular components and proposed potential relationships of ARM with established memory types in Drosophila and vertebrates. [ABSTRACT FROM AUTHOR]

Gynogenesis is a chromosome set manipulation technique to accelerate inbred lines used for genomics analysis and genetic breeding. Groupers are hermaphroditic fish whereby they sexually mature as females and subsequently change sex to male. Production of the homozygous inbred lines of groupers will take a prolonged period with the traditional method. This study presents the meiotic gynogenesis induction of the commercially cultured grouper Epinephelus fuscoguttatus, using a combination of ultraviolet-irradiated heterogenous sperm of E. lanceolatus and recovering second polar body by cold-shock treatment. DNA ploidy verification by flow cytometry showed that the haploid larvae exhibited abnormalities and diploids developed normally. The results indicated that UV irradiation doses at 150 ​mJ/cm2 produced 100% haploid larvae. The high percentage (52.1% ​± ​8.50%) of gynogenetic diploidy was induced by cold shock at 5–7 ​°C for 10 ​min, initiated 6 ​min after fertilization. The gynogenetic offspring presented 48 chromosomes (2n ​= ​48t) and were morphologically identical to maternal chromosomes. Cytological and morphological evidence suggested that gynogenetic individuals were successfully obtained. Histological examination revealed that the gynogens gonads could develop into ovaries. Summarily, the gynogenesis technique was very representative of creating inbred lines in groupers. The successful production of this inbred lines is of great significance in grouper genetic breeding and genomic analysis.

This study evaluated the application of cold shock combined with perforation-mediated passive modified atmosphere packaging technology (CS-PMAP) for cucumber preservation through physicochemical, sensory, and nutritional qualities. The effectiveness of CS-PMAP in maintaining the quality of fresh cucumbers was studied; cucumbers were pretreated with cold shock and then packed into perforated polyethylene bags (bag size of 20 × 30 cm; film thickness of 0.07 mm; and two holes in each bag with a diameter of 6 mm), while the cucumbers without cold shock were considered as the control. Storage of the samples was performed at (13 ± 2) °C for 20 days to determine the quality changes in terms of gas composition, weight loss, skin color, texture, total soluble solids (TSS), ascorbic acid, malondialdehyde (MDA), and volatile organic compounds (VOCs). The CS-PMAP showed a significant improvement in maintaining firmness, TSS, ascorbic acid, and flavor profile of cucumbers; the control samples without cold shock showed higher weight loss and MDA levels. Results of this study confirmed that CS-PMAP has potential use in the storage of cucumbers. [ABSTRACT FROM AUTHOR]

Temperature is critical in regulating virtually all biological functions in fish. Low temperature stress (cold shock/stress) is an often‐overlooked challenge that many fish face as a result of both natural events and anthropogenic activities. In this study, we present an updated review of the cold shock literature based on a comprehensive literature search, following an initial review on the subject by M.R. Donaldson and colleagues, published in a 2008 volume of this journal. We focus on how knowledge on cold shock and fish has evolved over the past decade, describing advances in the understanding of the generalized stress response in fish under cold stress, what metrics may be used to quantify cold stress and what knowledge gaps remain to be addressed in future research. We also describe the relevance of cold shock as it pertains to environmental managers, policymakers and industry professionals, including practical applications of cold shock. Although substantial progress has been made in addressing some of the knowledge gaps identified a decade ago, other topics (e.g., population‐level effects and interactions between primary, secondary and tertiary stress responses) have received little or no attention despite their significance to fish biology and thermal stress. Approaches using combinations of primary, secondary and tertiary stress responses are crucial as a research priority to better understand the mechanisms underlying cold shock responses, from short‐term physiological changes to individual‐ and population‐level effects, thereby providing researchers with better means of quantifying cold shock in laboratory and field settings. [ABSTRACT FROM AUTHOR]

Abstract Background Managing the limits of temperature adaptation is relevant both in medicine and in biotechnology. There are numerous scattered publications on the identification of the temperature limits of existence for various organisms and using different methods. Dmitry Petrovich Kharakoz gave a general explanation for many of these experimental results. The hypothesis implied that each cycle of synaptic exocytosis includes reversible phase transitions of lipids of the presynaptic membrane due to the entry and subsequent removal of calcium ions from the synaptic terminal. The correspondence of the times of phase transitions has previously been experimentally shown on isolated lipids in vitro. In order to test the hypothesis of D.P. Kharakoz in vivo, we investigated the influence of the temperature of long-term acclimatization on the temperature of heat and cold shock, as well as on the kinetics of temperature adaptation in zebrafish. Testing the hypothesis included a comparison of our experimental results with the results of other authors obtained on various models from invertebrates to humans. Results The viability polygon for Danio rerio was determined by the minimum temperature of cold shock (about 6 °C), maximum temperature of heat shock (about 43 °C), and thermopreferendum temperature (about 27 °C). The ratio of the temperature range of cold shock to the temperature range of heat shock was about 1.3. These parameters obtained for Danio rerio describe with good accuracy those for the planarian Girardia tigrina, the ground squirrel Sermophilus undulatus, and for Homo sapiens. Conclusions The experimental values of the temperatures of cold shock and heat shock and the temperature of the thermal preferendum correspond to the temperatures of phase transitions of the lipid-protein composition of the synaptic membrane between the liquid and solid states. The viability range for zebrafish coincides with the temperature range, over which enzymes function effectively and also coincides with the viability polygons for the vast majority of organisms. The boundaries of the viability polygon are characteristic biological constants. The viability polygon of a particular organism is determined not only by the genome, but also by the physicochemical properties of lipids that make up the membrane structures of synaptic endings. The limits of temperature adaptation of any biological species are determined by the temperature range of the functioning of its nervous system.

• Cold shock alters cell components, impacting cell membrane and intracellular structure. • Lowering temperature enhances calcium flux, crucial for sperm motility, especially in the flagellum. • this temperature below 20 °C can lead to the activation of calcium-absorbing protein channels in the shortest possible time. • Mild cold shock boosts proton-pumping, increasing activity for improved sperm function. • Cooling initiates tyrosine phosphorylation, a process vital for sperm capacitation. • Increased motility leads to a higher Total Motile Sperm Count (TMSC) index. Asthenozoospermia, characterized by reduced progressive motility (below 32%), is a leading cause of male infertility. Intrauterine Insemination (IUI) serves as the first-line treatment in sperm-related processes, aiming to increase sperm motility. Although Density Gradient Centrifugation (DGC) and swim-up procedures have become primary treatment options, considered the gold standard for IUI, there is a need to optimize these methods with additional factors to enhance motility, particularly for Asthenozoospermia patients. We hypothesize that a brief cold shock, lasting approximately 15–20 min at 17 °C, followed by incubation and sperm processing, can substantially enhance motility. For the first time, the hypothesis and evaluation of post-exposure incubation following a short-term cold shock, within the temperature range of 17–20 °C, were explored and discussed. This hypothesis appears valid and holds importance for several reasons. Firstly, there is a significant relationship between cold shock and its impact on intracellular components and the molecular organization of the cell membrane. Additionally, this process regulates various physiological cellular processes, including transbilayer distribution, acrosome reaction, and sperm motility. Moreover, lowering the temperature induces a molecular flux, facilitating calcium uptake by sperm. This process significantly impacts the quantity of calcium accessible to the sperm, particularly within the flagellum. Choosing the temperature below 20 °C temperature can lead to the activation of calcium-absorbing protein channels in the shortest possible time. Furthermore, a crucial reaction in IUI is sperm capacitation, which occurs when the protein tyrosine phosphorylation pathway, a key factor, is activated. Alternatively, the cold incubation of sperm reveals an increased level of tyrosine phosphorylation and a higher percentage of induced Acrosome Reaction (AR) compared to sperm incubated at normal temperatures. Hence, when sperm is cooled, it initiates a process called tyrosine phosphorylation, ultimately leading to sperm capacitation. Besides these logical reasons, there is limited empirical and incidental support in two cases that confirmed the hypothesis well. [ABSTRACT FROM AUTHOR]

The matrix permeability of shale is on the order of nanodarcy (nD), and hydrocarbon recovery from it is economical only after hydraulic fracturing. Another fracturing technique, which is often overlooked, is cryogenic fracturing. This study determines the effects of cold shock on shale permeability by focusing on the sub-100-nm pore throats that control access to a significant fraction of the pore space in the matrix. We extracted shale samples, heated them to mimic various formation burial depths, and shocked them in liquid nitrogen. Subsequently, we measured their capillary pressures. This study presents a conceptual model to shed light on the heterogeneous deformations at a sub-100-μm scale. Also, it uses a network modeling approach to determine the permeability enhancement based on the pore-throat size distributions obtained from the capillary pressure measurements. It demonstrates that cold shock enhances permeability by 20%, significantly lower than the typical values reported in the literature where the effects of subsurface temperature have been neglected. The enhancement depends non-monotonically on the temperature difference applied. Moreover, the results indicate that there may be an optimal scenario to maximize the enhancement that can only be determined experimentally. The reason for the incapability of the purely analytical approach is also discussed. • The effects of cryogenic fracturing on shale permeability are determined. • Shale permeability increases non-monotonically with the treatment conditions. • The optimum scenario occurred at 150 °C, and the permeability increased by 20%. • Unrealistic thermal conditions overestimate the increase (up to 2–3 times). • The optimal scenario could only be determined experimentally because of heterogeneity. [ABSTRACT FROM AUTHOR]

Background/Aim: The microminipig is a relatively new type of mini pig; microminipigs weigh about 10 kg at 6 months of age and are expected to be of use in drug discovery research and safety tests. Herein, we analyzed the characteristics of ejaculated sperm from microminipigs. Materials and Methods: Sperm parameters such as microstructure and sensitivity to cold shock were investigated using optical or scanning electron microscopy. Results: Ejaculate volumes and total numbers of sperm were lower than in standard pig strains, but were proportional to body weight. Ejaculation time, pH of the ejaculate, sperm motility and morphology, and sensitivity to cold shock were similar to those of standard pig strains. Conclusion: Herein, we provide the first characterization of the ejaculates of microminipigs and demonstrate that this type of pig will be useful not only in medical research, but also in investigations into sperm preservation in different pig breeds. [ABSTRACT FROM AUTHOR]

Background: One of the most challenging environmental extremes is immersion in cold/icy water, and consequent common assumption is that even a brief exposure to cold can lead to cold-related illnesses. The increase in the concentrations of the stress hormones cortisol, epinephrine (Epi), and norepinephrine (NE) in response to acute cold stress are thought to suppress the release of proinflammatory cytokines. No previous study has explored the residual consequences of whole-body short-term cold-water immersion (CWI; 14 °C for 10 min) on the immune response in healthy non-acclimated young adult men (aged 20–30 years). Materials and methods: In the current study, we tested the hypothesis that short-term acute whole-body CWI would induce high blood levels of cortisol, NE, and Epi, which in turn would increase circulating leukocyte numbers and delay the production of proinflammatory cytokines (tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β), and IL-6). Results: Short-term whole-body CWI produced a stressful physiological reaction, as manifested by hyperventilation and increased muscle shivering, metabolic heat production, and heart rate. CWI also induced the marked release of the stress hormones Epi, NE, and cortisol. The change in IL-6 concentration after CWI was delayed and TNF-α production was decreased, but IL-1β was not affected within 48 h after CWI. A delayed increase in neutrophil percentage and decrease in lymphocyte percentage occurred after CWI. Conclusion: These findings suggest that, even though CWI caused changes in stress and immune markers, the participants showed no predisposition to symptoms of the common cold within 48 h after CWI.

In Manitoba, Canada, wild lake sturgeon (Acipenser fulvescens) populations exist along a latitudinal gradient and are reared in hatcheries to bolster threatened populations. We reared two populations of lake sturgeon, one from each of the northern and southern ends of Manitoba and examined the effects of typical hatchery temperatures (16°C) as well as 60‐day acclimation to elevated rearing temperatures (20°C) on mortality, growth and condition throughout early development. Additionally, we examined the cold shock response, which may be induced during stocking, through the hepatic mRNA expression of genes involved in the response to cold stress and homeoviscous adaptation (HSP70, HSP90a, HSP90b, CIRP and SCD). Sturgeon were sampled after 1 day and 1 week following stocking into temperatures of 8, 6 and 4°C in a controlled laboratory environment. The southern population showed lower condition and higher mortality during early life than the northern population while increased rearing temperature impacted the growth and condition of developing northern sturgeon. During the cold shock, HSP70 and HSP90a mRNA expression increased in all sturgeon treatments as stocking temperature decreased, with higher expression observed in the southern population. Expression of HSP90b, CIRP and SCD increased as stocking temperature decreased in northern sturgeon with early acclimation to 20°C. Correlation analyses indicated the strongest molecular relationships were in the expression of HSP90b, CIRP and SCD, across all treatments, with a correlation between HSP90b and body condition in northern sturgeon with early acclimation to 20°C. Together, these observations highlight the importance of population and rearing environment throughout early development and on later cellular responses induced by cold stocking temperatures. [ABSTRACT FROM AUTHOR]

Abstract Background Abiotic stresses like low temperatures are contributory factors to the variations observed among species during plant germination, growth, and development. The present study evaluated the morphological and genetic responses of maize (Zea mays L.) seedling to cold shock induced by a one-time exposure to low temperature. Seeds were originally exposed to distilled water at room temperature for 48 h before they were completely submerged in buckets of ice for 0.5, 1.5, 3, 6, and 12 h, respectively, and then transferred into Petri dishes. The set up was left on the laboratory bench for an additional 5 days, and plant germination parameters were measured. DNA was extracted and this was followed by RAPD—polymerase chain reaction. Results Significant growth impairment upon exposure to cold shock corresponding to the length of time of exposure was shown. The length of the prominent root significantly reduced upon exposure to a cold shock from 141.8 mm to as low as 91.4 mm in those plants exposed at 1.5 h. The length of the prominent leaf also significantly reduced from 100.6 mm in the control to between 62.6 and 85.5 mm in low-temperature-exposed plants (p < 0.05), notwithstanding the time of exposure. There were significant reductions in final germination percent in the low-temperature-exposed germinants (35.8–60.5%) when compared to the control (88.5%). The RAPD marker (OPA04) revealed variations in germinated maize seeds after treatment with different duration of low temperatures. The test plantlets treated for 0, 0.5, and 1.5 h have an unrecognizable complementary sequence to the primer OPA04, whereas the primer amplified regions of the genome of test plantlets treated for 3, 6, and 12 h. Primer OPA05 also presented diversity among maize seedlings stressed for various durations of cold shock. Conclusion The existence of genetic variations in the present study has far-reaching effects on the development of maize exposed to varying degrees of cold stress. Though restricted to germination only, they are important because the development of plants begins at the germination stage. These changes may affect the characteristics of economic importance or perhaps impact on the physiology of the maize plant eventually.

Abstract Background Cellular reprogramming in response to environmental stress involves alteration of gene expression, changes in the protein and metabolite profile for ensuring better stress management in plants. Similar to other plant species originating in tropical and sub-tropical areas, indica rice is highly sensitive to low temperature that adversely affects its growth and grain productivity. Substantial work has been done to understand cold induced changes in gene expression in rice plants. However, adequate information is not available for early gene expression, especially in indica variety. Therefore, a transcriptome profile was generated for cold shock treated seedlings of IR64 variety to identify early responsive genes. Results The functional annotation of early DEGs shows enrichment of genes involved in altered membrane rigidity and electrolytic leakage, the onset of calcium signaling, ROS generation and activation of stress responsive transcription factors in IR64. Gene regulatory network suggests that cold shock induced Ca2+ signaling activates DREB/CBF pathway and other groups of transcription factors such as MYB, NAC and ZFP; for activating various cold-responsive genes. The analysis also indicates that cold induced signaling proteins like RLKs, RLCKs, CDPKs and MAPKK and ROS signaling proteins. Further, several late-embryogenesis-abundant (LEA), dehydrins and low temperature-induced-genes were upregulated under early cold shock condition, indicating the onset of water-deficit conditions. Expression profiling in different high yielding cultivars shows high expression of cold-responsive genes in Heera and CB1 indica varieties. These varieties show low levels of cold induced ROS production, electrolytic leakage and high germination rate post-cold stress, compared to IR36 and IR64. Collectively, these results suggest that these varieties may have improved adaptability to cold stress. Conclusions The results of this study provide insights about early responsive events in Oryza sativa l.ssp. indica cv IR64 in response to cold stress. Our data shows the onset of cold response is associated with upregulation of stress responsive TFs, hydrophilic proteins and signaling molecules, whereas, the genes coding for cellular biosynthetic enzymes, cell cycle control and growth-related TFs are downregulated. This study reports that the generation of ROS is integral to the early response to trigger the ROS mediated signaling events during later stages.

This study was dealt with induction of diploid meiotic and mitotic gynogenesis in Barbonymus gonionotus through cold shock treatment for production of monosex all-female population. For inhibition of paternal inheritance, sperm DNA was denatured by exposing cell suspension containing 8×108 ml-1 to UV at 196 μWcm-2 for 1.5 min. After fertilization of eggs using uv-treated sperm, meiotic diploidization was done by cold shock treatment at 2 °C for 1 min applied 1.5 min of post-fertilization that produced 44.23±0.62% meiotic gynogens. Mitotic diploidization was done by the same cold shock treatment applied after 27.5 min of fertilization that produced 36.70±0.63% mitotic gynogens. Ploidy status of all the progenies was evaluated by karyotyping. The karyotype analysis revealed 23 (N) chromosomes in haploids, and 46 (2N) chromosomes in meiotic and mitotic gynogens and controls. Sexing of fish showed nearly all-female, ranging from 98.28 to 100% and 96.43 to 100% female in the meiotic and mitotic gynogens respectively. The sex ratio in the control group was nearly 1:1. DNA microsatellite analysis revealed that the meiotic gynogenetic offspring possessed two alleles the same as their mother and the mitotic gynogenetic offspring possessed any of the two alleles of their mother and became homozygous. No meiotic and mitotic gynogens have inheritance of paternal alleles. The control offspring shared alleles from both male and female parents. Thus, the study confirmed the production of meiotic and mitotic gynogens of silver barb through cold shock treatment and they could be converted into sex-reversed males (XX) by masculinizing hormone treatment for production of monosex all-female population. [ABSTRACT FROM AUTHOR]

This study aimed to analyze the cold stress effects (in terms of hematology, energy reserves, and oxidative stress) in Piaractus mesopotamicus (pacú) and their mitigation by a Pyropia columbina red seaweed-supplemented diet. For this purpose, juvenile fish were fed with a control (CD) or a red seaweed-supplemented diet (RD) for 60 days, and then, the animals were exposed to a low temperature (14 °C) and a control temperature (24 °C) for 24 h. The cold shock generated an increase of hemoglobin levels in fish fed with both diets. In CD-fed fish, plasmatic triglycerides, cholesterol, and hepatic glycogen decreased after the thermal shock; meanwhile, the animals fed with RD showed decreased hepatic proteins, but increased cholesterol and hepatic glycogen. Regarding oxidative stress, antioxidant enzymes augmented their activity in the liver, intestine, and gills; meanwhile, lipid oxidative damage was observed in the liver and intestine of fish exposed to 14 °C and fed with both diets. Pacú was sensitive to cold shock, but no mitigation effects were observed in fish fed with the supplemented diet. Further research should target higher concentrations of P. columbina in supplemented diets to take advantage of this valuable resource. [ABSTRACT FROM AUTHOR]

ABSTRACT To maintain optimal membrane dynamics, cells from all domains of life must acclimate to various environmental signals in a process referred to as homeoviscous adaptation. Alteration of the lipid composition is critical for maintaining membrane fluidity, permeability of the lipid bilayer, and protein function under diverse conditions. It is well documented, for example, that glycerophospholipid content varies substantially in both Gram-negative and Gram-positive bacteria with changes in growth temperature. However, in the case of Gram-negative bacteria, far less is known concerning structural changes in lipopolysaccharide (LPS) or lipooligosaccharide (LOS) during temperature shifts. LPS/LOS is anchored at the cell surface by the highly conserved lipid A domain and localized in the outer leaflet of the outer membrane. Here, we identified a novel acyltransferase, termed LpxS, involved in the synthesis of the lipid A domain of Acinetobacter baumannii. A. baumannii is a significant, multidrug-resistant, opportunistic pathogen that is particularly difficult to clear from health care settings because of its ability to survive under diverse conditions. LpxS transfers an octanoate (C8:0) fatty acid, the shortest known secondary acyl chain reported to date, replacing a C12:0 fatty acid at the 2′ position of lipid A. Expression of LpxS was highly upregulated under cold conditions and likely increases membrane fluidity. Furthermore, incorporation of a C8:0 acyl chain under cold conditions increased the effectiveness of the outer membrane permeability barrier. LpxS orthologs are found in several Acinetobacter species and may represent a common mechanism for adaptation to cold temperatures in these organisms. IMPORTANCE To maintain cellular fitness, the composition of biological membranes must change in response to shifts in temperature or other stresses. This process, known as homeoviscous adaptation, allows for maintenance of optimal fluidity and membrane permeability. Here, we describe an enzyme that alters the fatty acid content of A. baumannii LOS, a major structural feature and key component of the bacterial outer membrane. Although much is known regarding how glycerophospholipids are altered during temperature shifts, our understanding of LOS or LPS alterations under these conditions is lacking. Our work identifies a cold adaptation mechanism in A. baumannii, a highly adaptable and multidrug-resistant pathogen.

Stress response helps microorganisms survive extreme environmental conditions and host immunity, making them more virulent or drug resistant. Although both reductionist approaches investigating specific genes and systems approaches analyzing individual stress conditions are being used, less is known about gene networks involved in multiple stress responses. Here, using a systems biology approach, we mined hundreds of transcriptomic data sets for key genes and pathways involved in the tolerance of the model microorganism Escherichia coli to multiple stressors. Specifically, we investigated the E. coli K-12 MG1655 transcriptome under five stresses: heat, cold, oxidative stress, nitrosative stress, and antibiotic treatment. Overlaps of transcriptional changes between studies of each stress factor and between different stressors were determined: energy-requiring metabolic pathways, transport, and motility are typically downregulated to conserve energy, while genes related to survival, bona fide stress response, biofilm formation, and DNA repair are mainly upregulated. The transcription of 15 genes with uncharacterized functions is higher in response to multiple stressors, which suggests they may play pivotal roles in stress response. In conclusion, using rank normalization of transcriptomic data, we identified a set of E. coli stress response genes and pathways, which could be potential targets to overcome antibiotic tolerance or multidrug resistance.