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Speciation is a continuous process driven by barriers to gene flow. Based on genome‐wide SNPs (single nucleotide polymorphisms) of 190 toads from 31 sampling sites of Scutiger boulengeri complex, we found evidence for monophyly which represented a continuous speciation process of at least six lineages in S. boulengeri, which radiated and exhibited varying degrees of divergence and gene flow. The SNP‐based phylogenetic tree was largely discordant with the multilocus mitochondrial tree (i.e., S. mammatus and S. glandulatus nested in the lineages of S. boulengeri) published before. The Min Mountains (MM) and Qinghai‐Tibet Plateau (QTP) lineages differ fundamentally in habitat (i.e., elevation) and morphology (i.e., SVL), we detected signatures of potential high‐altitude and cold adaptation genes in QTP (vs. MM). We found the evidence of reproductive trait disparity (i.e., SVL and nuptial pads) is key to promoting sympatric rather than allopatric species pairs. In addition, we identified selection signals for genes related to sympatric character displacement, genes linked to obesity‐related traits, nuptial spines morphology and enlarged chest nuptial pads in S. mammatus (vs. QTP group of S. boulengeri). Our study provided new insight and paradigm for a varied speciation pattern from local adaptation of allopatry to sympatric character displacement in the S. boulengeri complex. [ABSTRACT FROM AUTHOR]

ABSTRACT With global climate change, understanding how conifers manage seasonal dormancy is increasingly important. This study explores the physiological and molecular processes controlling dormancy transitions in P. tabuliformis, a key species in northern China. Using dormancy simulations and Time‐Ordered Gene Co‐Expression Network (TO‐GCN) analysis, we identified low temperature, rather than photoperiod, as the primary trigger for dormancy release. The PtTFL2 gene functions as both an environmental sensor and dormancy marker, regulated by cold‐dependent and independent pathways involving the photoperiod‐responsive PtCOL1 and PtSVP‐like (SVL) genes. During the autumn‐to‐winter transition, PtSVL controls PtTFL2 transcription, forming a regulatory complex to fine‐tune dormancy. PtCOL1 also directly regulates PtTFL2 and indirectly modulates it by affecting PtSVL expression. The CO‐TFL module controls fall dormancy (ecodormancy), while the SVP‐TFL module manages the shift to endodormancy in winter. These findings reveal dual regulatory pathways governing dormancy in conifers, offering insights into their adaptation to cold environments and laying the foundation for further research into dormancy mechanisms in gymnosperms. [ABSTRACT FROM AUTHOR]

Fungi, which are widely distributed across the Earth, have successfully managed to colonize cold environments (e.g., polar regions, alpine ecosystems, and glaciers) despite the challenging conditions for life. They are capable of living in extremely harsh environments due to their ecological versatility and morphological plasticity. It is also believed that lower eukaryotes are the most adapted to life at low temperatures among microorganisms that thrive in cold environments. They play important ecological roles, contributing to nutrient recycling and organic matter mineralization. These highly specialized microorganisms have developed adaptation strategies to overcome the direct and indirect harmful influences of low temperatures. They have evolved a wide range of complex and cooperative adaptations at various cellular levels, including modifications to the cell envelope and enzymes, the production of cryoprotectants and chaperones, and the development of new metabolic functions. Adaptation to cold environments has made fungi an exciting source for the discovery of new cold-adapted enzymes (e.g., proteinases, lipases) and secondary metabolites (e.g., pigments, osmolytes, polyunsaturated fatty acids) for widespread use in biotechnology, food technology, agriculture, pharmaceutics, molecular biology, textile industry, and environmental bioremediation in cold climates. This review aims to provide a comprehensive overview of the adaptive strategies employed by psychrophilic yeasts and fungi, highlighting their ecological roles and biotechnological potential. Understanding these adaptive mechanisms not only sheds light on microbial life in extreme environments but also paves the way for innovative applications in the food industry and agriculture. [ABSTRACT FROM AUTHOR]

Bees play important roles in socio-economic development, biodiversity conservation, and ecosystem stability. However, during the cold season, resources become limited, leading to significant losses in bee colonies. Although many studies have described the characteristics of winter bees and demonstrated that notable changes occur in their gut microflora, the underlying mechanisms remain yet to be fully elucidated. Therefore, this study was conducted to compare the gut microbiota dynamics of overwintering bees. Sample acquisition involved randomly selecting ten colonies each from three bee farms containing Apis cerana (AC) and Apis mellifera (AM), followed by dissection for further analysis. DNA was extracted, and 16S rDNA sequencing, along with various bioinformatics tools, was used to assess microbial diversity, functional differences, and species comparisons between AC and AM gut microbiota. AC exhibited lower β diversity in the gut microbiota than AM during winter. Moreover, Gilliamella and Apibacter were relatively more abundant in AC. Regarding microbial functions, key pathways included the phosphotransferase system, galactose metabolism, the pentose phosphate pathway, and carbohydrate transport and metabolism. These results suggest the presence of microbial diversity differences between AC and AM, with the differential microbial functions mainly enriched in metabolic pathways that facilitate adaptation to cold environmental stress. [ABSTRACT FROM AUTHOR]

Cold-active enzymes have recently gained popularity because of their high activity at lower temperatures than their mesophilic and thermophilic counterparts, enabling them to withstand harsh reaction conditions and enhance industrial processes. Cold-active lipases are enzymes produced by psychrophiles that live and thrive in extremely cold conditions. Cold-active lipase applications are now growing in the detergency, synthesis of fine chemicals, food processing, bioremediation, and pharmaceutical industries. The cold adaptation mechanisms exhibited by these enzymes are yet to be fully understood. Using phylogenetic analysis, and advanced deep learning-based protein structure prediction tool Alphafold2, we identified an evolutionary processes in which a conserved cold-active-like motif is presence in a distinct subclade of the tree and further predicted and simulated the three-dimensional structure of a putative cold-active lipase with the cold active motif, Glalip03, from Glaciozyma antarctica PI12. Molecular dynamics at low temperatures have revealed global stability over a wide range of temperatures, flexibility, and the ability to cope with changes in water and solvent entropy. Therefore, the knowledge we uncover here will be crucial for future research into how these low-temperature-adapted enzymes maintain their overall flexibility and function at lower temperatures. [ABSTRACT FROM AUTHOR]

The article discusses the evolution of brown adipose tissue (BAT) and the key mitochondrial protein, uncoupling protein 1 (UCP1), which enables heat production in mammals. Research shows that UCP1 gained its thermogenic ability in the stem ancestor of placental mammals, sparking BAT thermogenesis exclusively in the placental lineage. The study explores the evolutionary origins of UCP1-dependent thermogenesis, shedding light on the unique trait among placental mammals and their enhanced thermoregulatory mechanisms. This research provides insights into the evolution of mammalian thermogenesis and raises questions about alternative thermogenic mechanisms in non-placental mammals. [Extracted from the article]

In understanding stress response mechanisms in fungi, cold stress has received less attention than heat stress. However, cold stress has shown its importance in various research fields. The following study examined the cold stress response of six Pseudogymnoascus spp. isolated from various biogeographical regions through a proteomic approach. In total, 2541 proteins were identified with high confidence. Gene Ontology enrichment analysis showed diversity in the cold stress response pathways for all six Pseudogymnoascus spp. isolates, with metabolic and translation-related processes being prominent in most isolates. 25.6% of the proteins with an increase in relative abundance were increased by more than 3.0-fold. There was no link between the geographical origin of the isolates and the cold stress response of Pseudogymnoascus spp. However, one Antarctic isolate, sp3, showed a distinctive cold stress response profile involving increased flavin/riboflavin biosynthesis and methane metabolism. This Antarctic isolate (sp3) was also the only one that showed decreased phospholipid metabolism in cold stress conditions. This work will improve our understanding of the mechanisms of cold stress response and adaptation in psychrotolerant soil microfungi, with specific attention to the fungal genus Pseudogymnoascus. [ABSTRACT FROM AUTHOR]

Separation of duplex strands of nucleic acids is a vital process in the nucleic acid metabolism and survival of all living organisms. Helicases are defined as enzymes that are intended to unwind the double-stranded nucleic acids. Helicases play a prominent role in the cold adaptation of plants and bacteria. Cold stress can increase double-strand DNA breaks, generate reactive oxygen species, cause DNA methylation, and stabilize the secondary structure of RNA molecules. In this review, we discuss how helicases play important roles in adaptive responses to cellular stress caused by low temperature conditions, particularly in bacteria and plants. We also provide a glimpse of the eminence of helicase function over nuclease when an enzyme has both helicase and nuclease functions. [ABSTRACT FROM AUTHOR]

Malate dehydrogenases (MalDHs) (EC.1.1.1.37), which are involved in the conversion of oxaloacetate to pyruvate in the tricarboxylic acid cycle, are a relevant model for the study of enzyme evolution and adaptation. Likewise, a recent study showed that Methanococcales , a major lineage of Archaea , is a good model to study the molecular processes of proteome thermoadaptation in prokaryotes. Here, we use ancestral sequence reconstruction and paleoenzymology to characterize both ancient and extant MalDHs. We observe a good correlation between inferred optimal growth temperatures and experimental optimal temperatures for activity (A-Topt). In particular, we show that the MalDH present in the ancestor of Methanococcales was hyperthermostable and had an A-Topt of 80 °C, consistent with a hyperthermophilic lifestyle. This ancestor gave rise to two lineages with different thermal constraints: one remained hyperthermophilic, while the other underwent several independent adaptations to colder environments. Surprisingly, the enzymes of the first lineage have retained a thermoresistant behavior (i.e. strong thermostability and high A-Topt), whereas the ancestor of the second lineage shows a strong thermostability, but a reduced A-Topt. Using mutants, we mimic the adaptation trajectory toward mesophily and show that it is possible to significantly reduce the A-Topt without altering the thermostability of the enzyme by introducing a few mutations. Finally, we reveal an unexpected link between thermostability and the ability to resist γ-irradiation-induced unfolding. [ABSTRACT FROM AUTHOR]

In the Antarctic marine ecosystem, krill play a pivotal role, yet the intricate microbial community intertwined with these diminutive crustaceans remains largely unmapped. In this study, we successfully isolated and characterized a unique bacterial strain, Pseudoalteromonas sp. WY3, from Antarctic krill. Genomic analysis revealed that WY3 harbors a multitude of genes associated with cold shock proteins, oxidoreductases, and enzymes involved in the osmotic stress response, equipping it with a robust molecular arsenal to withstand frigid Antarctic conditions. Furthermore, the presence of two distinct biosynthesis-related gene clusters suggests that WY3 has the potential to synthesize diverse secondary metabolites, including aryl polyenes and ribosomally synthesized and post-translationally modified peptides. Notably, the identification of genes encoding enzymes crucial for biological immunity pathways, such as apeH and ubiC , hints at a complex symbiotic relationship between WY3 and its krill host. This comprehensive study highlights the robust potential of WY3 for secondary metabolite production and its remarkable ability to thrive at extremely low temperatures in the Antarctic ecosystem, shedding light on the interplay between culturable microorganisms and their hosts in harsh environments, and providing insights into the underexplored microbial communities associated with Antarctic marine organisms and their role in environmental adaptation and biotechnological applications. [ABSTRACT FROM AUTHOR]

Many patients with COVID-19 experience increased arterial stiffness and abnormal cerebral hemodynamics. Although previous studies have explored the effects of cold environments on cardiovascular health and cerebral hemodynamics, there is still no research on the changes in cardiovascular and cerebral hemodynamics in sedentary female students recovering from COVID-19 while performing high-intensity interval training (HIIT) in cold environments. This study investigates the effects of 1 week of HIIT in a cold environment on cerebral hemodynamics and arterial stiffness (AS) in sedentary female college students, providing new insights into the pathophysiological mechanisms in this specific context. Thirty-six participants were randomly divided into a control group (n = 12), a room temperature (RE) group (n = 12), and a cold environment (CE) group (n = 12). HIIT was performed for four 4-min running training sessions, with a 4-min interval between each training session, The training duration was 1 week, with a frequency of 2 sessions per day, while the control group did not undergo any training. After training, the AS in the CE group significantly decreased (p < 0.05), with an average reduction of 11% in brachial-ankle pulse wave velocity, showing a significantly greater improvement compared to the RE group and the control group (p < 0.05), while no significant changes were observed in the RE group (p > 0.05). In the Y-Balance Tests (YBTs), the concentrations of cerebral oxygenated hemoglobin and total hemoglobin significantly increased (p < 0.05) during unilateral leg support tests in both the CE and RE groups, and the increase of CE group is greater than that of RE group. In contrast, in the control group, the concentrations of cerebral oxygenated hemoglobin and total hemoglobin significantly decreased during left leg support (p < 0.05). Our study found that performing HIIT in a cold environment not only effectively reduces AS in sedentary female college students after COVID-19, improves cardiovascular function, but also significantly enhances cerebral hemodynamics, helping them alleviate the negative impacts of post-COVID-19 sequelae and sedentary behavior on health. Future research should further explore the mechanisms by which sedentary behavior, post-COVID-19 recovery status, and adaptation to cold environments collectively influence cardiovascular function and cerebral hemodynamics, providing a more comprehensive understanding of these factors. [ABSTRACT FROM AUTHOR]

Despite previous culture-independent studies highlighting the prevalence of the order Burkholderiales in deep-sea environments, the cultivation and characterization of deep-sea Burkholderiales have been infrequent. A total of 243 deep-sea bacterial strains were isolated from various depths in the Northwest Pacific Ocean, with 33 isolates (13.6%) from a depth of 4000 m classified into Burkholderiales. Herein, we report the isolation and genome characteristics of strain SAORIC-580T, from a depth of 4000 m in the Northwest Pacific Ocean. The strain showed a close phylogenetic relationship with Limnobacter thiooxidans CS-K2T, sharing 99.9% 16S rRNA gene sequence identity. The complete whole-genome sequence of strain SAORIC-580T comprised 3.3 Mbp with a DNA G+C content of 52.5%. Comparative genomic analysis revealed average nucleotide identities between 79.4–85.7% and digital DNA-DNA hybridization values of 19.9–29.5% when compared to other Limnobacter genomes, indicating that the strain represents a novel species within the genus. Genomic analysis revealed unique adaptations to deep-sea conditions, including genes associated with phenol degradation, stress responses, cold adaptation, heavy metal resistance, signal transduction, and carbohydrate metabolism. The SAORIC-580T genome was found to be more abundant in the deep sea than at the surface in the trenches of the Northwest Pacific Ocean, suggesting adaptations to the deep-sea environment. Phenotypic characterization highlighted distinct differences from other Limnobacter species, including variations in growth conditions, enzyme activities, and phenol degradation capabilities. Chemotaxonomic markers of the strain included ubiquinone-10, major fatty acids such as C16:0, C16:1, and C18:1, and major polar lipids including phosphatidylethanolamine, phosphatidylglycerol, and diphosphatidylglycerol. Based on the polyphasic taxonomic data, it is concluded that strain SAORIC-580T (= KACC 21440T = NBRC 114111T) represents a novel species, for which the name Limnobacter profundi sp. nov. is proposed. [ABSTRACT FROM AUTHOR]

The frigid and droughty climate of Xinjiang in China has given rise to unique indigenous sheep breeds with robust adaptability and resistance. To investigate the genetic mechanism of adaptability of Xinjiang sheep to the local extreme environment, we conducted population genetic structure analyses for three native Xinjiang sheep breeds: Altay sheep (ALT), Bashbay Sheep (BSBC), and Duolang sheep (DLC), as well as two foreign sheep breeds: Suffolk and Dorset, using the Ovine Infinium HD SNP BeadChip(680 K). Our findings revealed distinct genetic and evolutionary histories between Xinjiang and foreign sheep breeds. Principal Component Analysis (PCA) and phylogenetic tree effectively differentiate these five sheep breeds based on their geographical origins, and the domestication level of Xinjiang sheep is comparatively lower than that of foreign sheep breeds. Furthermore, by utilizing three selective signature methods, namely Fixation Index (Fst), Cross Population Extended Haplotype Homozygosity Test (XP-EHH), and Nucleotide Diversity (π), we have successfully identified 22 potential candidate genes. Among these genes, there are TBXT, PDGFD, and VEGFA, which are closely related to tail type and lipid metabolism; VIL1, SLC11A1, and ZBTB46, which are associated with immune function; and candidate genes such as BNC1, HDAC1, and BMP5, which impact sheep reproductive traits. This study establishes a foundation for conserving and utilizing local sheep germplasm resources in Xinjiang and provides molecular insights into the genetic mechanisms governing sheep adaptation to extreme cold and arid environments. [ABSTRACT FROM AUTHOR]

In response to cold, mammals activate brown fat for respiratory-dependent thermogenesis reliant on the electron transport chain. Yet, the structural basis of respiratory complex adaptation upon cold exposure remains elusive. Herein, we combined thermoregulatory physiology and cryoelectron microscopy (cryo-EM) to study endogenous respiratory supercomplexes from mice exposed to different temperatures. A cold-induced conformation of CI:III 2 (termed type 2) supercomplex was identified with a ∼25° rotation of CIII 2 around its inter-dimer axis, shortening inter-complex Q exchange space, and exhibiting catalytic states that favor electron transfer. Large-scale supercomplex simulations in mitochondrial membranes reveal how lipid-protein arrangements stabilize type 2 complexes to enhance catalytic activity. Together, our cryo-EM studies, multiscale simulations, and biochemical analyses unveil the thermoregulatory mechanisms and dynamics of increased respiratory capacity in brown fat at the structural and energetic level. [Display omitted] • CI:III 2 respiratory structures in cold-exposed brown fat show rotation of CIII2 • CIII 2 rotation enhances catalytic efficiency and electron transfer • Cold-induced membrane phospholipid remodeling supports formation of type 2 complexes High-resolution structures of respiratory I:III 2 complexes from brown fat adapted to cold temperatures reveal a distinct supercomplex assembly with rotated CIII 2 that displays higher electron transfer and catalytic efficiency, which has implications for increased respiration in response to physiological energy-demanding conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] During the past 3000 years, cattle on the Qinghai-Xizang Plateau have developed adaptive phenotypes under the selective pressure of hypoxia, ultraviolet (UV) radiation, and extreme cold. The genetic mechanism underlying this rapid adaptation is not yet well understood. Here, we present whole-genome resequencing data for 258 cattle from 32 cattle breeds/populations, including 89 Tibetan cattle representing eight populations distributed at altitudes ranging from 3400 m to 4300 m. Our genomic analysis revealed that Tibetan cattle exhibited a continuous phylogeographic cline from the East Asian taurine to the South Asian indicine ancestries. We found that recently selected genes in Tibetan cattle were related to body size (HMGA2 and NCAPG) and energy expenditure (DUOXA2). We identified signals of sympatric introgression from yak into Tibetan cattle at different altitudes, covering 0.64%–3.26% of their genomes, which included introgressed genes responsible for hypoxia response (EGLN1), cold adaptation (LRP11), DNA damage repair (LATS1), and UV radiation resistance (GNPAT). We observed that introgressed yak alleles were associated with noncoding variants, including those in present EGLN1. In Tibetan cattle, three yak introgressed SNPs in the EGLN1 promoter region reduced the expression of EGLN1 , suggesting that these genomic variants enhance hypoxia tolerance. Taken together, our results indicated complex adaptation processes in Tibetan cattle, where recently selected genes and introgressed yak alleles jointly facilitated rapid adaptation to high-altitude environments. [ABSTRACT FROM AUTHOR]

A novel heterotrophic, cold-tolerant bacterium, designated Pseudomonas zhanjiangensis 25A3ET, was isolated from mangrove sediment and demonstrated excellent efficiency in cold wastewater treatment. Phylogenetic analysis based on 16S rRNA gene sequences positioned strain 25A3ET within the genus Pseudomonas , showing the highest similarity (98.7%) with Pseudomonas kurunegalensis LMG 32023T. Digital DNA–DNA hybridization (dDDH) and average nucleotide identity (ANI) values were below the species delineation thresholds (70% for dDDH, 95% for ANI), indicating that strain 25A3ET represents a novel species. This strain demonstrated high efficiency in removing nitrogen (N) and organic pollutants under low-temperature conditions. Specifically, it achieved 72.9% removal of chemical oxygen demand (COD), 70.6% removal of ammoniacal nitrogen (NH4+-N), and 69.1% removal of total nitrogen (TN) after 96 h at 10°C. Genomic analysis identified key genes associated with cold adaptation, nitrogen removal and organic matter degradation. These findings indicate that Pseudomonas zhanjiangensis 25A3ET holds significant potential for application in cold temperature wastewater treatment, offering a promising solution for environmental remediation in regions with low ambient temperatures. [ABSTRACT FROM AUTHOR]

Background: Sepsis remains a major global health concern due to its high prevalence and mortality. Changes in body temperature (Tb), such as hypothermia or fever, are diagnostic indicators and play a crucial role in the pathophysiology of sepsis. This study aims to characterize the thermoregulatory mechanisms during sepsis using the cecal ligation and puncture (CLP) model and explore how sepsis severity and ambient temperature (Ta) influence Tb regulation and mortality. Rats were subjected to mild or severe sepsis by CLP while housed at thermoneutral (28 °C) or subthermoneutral (22 °C) Ta, and their Tb was monitored for 12 h. Blood and hypothalamus were collected for cytokines and prostaglandin E2 (PGE2) analysis. Results: At 28 °C, febrile response magnitude correlated with sepsis severity and inflammatory response, with tail vasoconstriction as the primary heat retention mechanism. At 22 °C, Tb was maintained during mild sepsis but dropped during severe sepsis, linked to reduced UCP1 expression in brown adipose tissue and less effective vasoconstriction. Despite differences in thermoregulatory responses, both Ta conditions induced a persistent inflammatory response and increased hypothalamic PGE2 production. Notably, mortality in severe sepsis was significantly higher at 28 °C (80%) compared to 22 °C (0%). Conclusions: Our findings reveal that ambient temperature and the inflammatory burden critically influence thermoregulation and survival during early sepsis. These results emphasize the importance of considering environmental factors in preclinical sepsis studies. Although rodents in experimental settings are often adapted to cold environments, these conditions may not fully translate to human sepsis, where cold adaptation is rare. Thus, researchers should carefully consider these variables when designing experiments and interpreting translational implications. [ABSTRACT FROM AUTHOR]

The fall armyworm (FAW), Spodoptera frugiperda is a cold-sensitive species that overwinters in temperate climates without diapause. Overwintering in insects involves rapid cold hardening (RCH), supported by trehalose (TRE), which serves as an intermediate between glycogen (GLY) and glucose (GLU). However, both GLU and TRE help maintain homeostasis under stress. TRE is hydrolyzed by the enzyme trehalase (Treh) into GLU. This study retrieved Sf-Treh1a, Sf-Treh1b, and Sf-Treh2 from the FAW transcriptome analysis. RNA interference (RNAi) targeting these three Treh genes resulted in significant downregulation of mRNA levels and altered survival rates in RNAi-treated FAW larvae following RCH treatment. High-pressure liquid chromatography (HPLC) quantification of TRE and GLU in treated groups suggests that GLU is an essential component of the hemolymph for survival adaptation to cold conditions in S. frugiperda. This study reveals limited cold adaptability of FAW, as evidenced by lower glucose concentration levels. We found that FAW requires alternative molecules, in conjunction with glucose and trehalose for freeze tolerance and survivability. Our study aims to discover the molecular mechanisms that contribute to freeze tolerance in FAW by exploring the roles of trehalose, glucose, and glycogen. [ABSTRACT FROM AUTHOR]

It is essential for the survival of grapevines in cool climate viticultural regions where vines properly acclimate in late fall and early winter and develop freezing tolerance. Climate change‐associated abnormities in temperature during the dormant season, including oscillations between prolonged warmth in late fall and extreme cold in midwinter, impact cold acclimation and threaten the sustainability of the grape and wine industry. We conducted two experiments in controlled environment to investigate the impacts of different temperature regimes on cold acclimation ability in endodormant grapevine buds through a combination of freezing tolerance‐based physiological and RNA‐seq‐based transcriptomic monitoring. Results show that exposure to a constant temperature, whether warm (22 and 11°C), moderate (7°C), or cool (4 and 2°C) was insufficient for triggering cold acclimation and increasing freezing tolerance in dormant buds. However, when the same buds were exposed to temperature cycling (7±5°C), acclimation occurred, and freezing tolerance was increased by 5°C. We characterized the transcriptomic response of endodormant buds to high and low temperatures and temperature cycling and identified new potential roles for the ethylene pathway, starch and sugar metabolism, phenylpropanoid regulation, and protein metabolism in the genetic control of endodormancy maintenance. Despite clear evidence of temperature‐responsive transcription in endodormant buds, our current understanding of the genetic control of cold acclimation remains a challenge when generalizing across grapevine tissues and phenological stages. [ABSTRACT FROM AUTHOR]

Mechanisms of adaptation to prolonged low temperature exposures, aimed at increasing thermogenesis and altering metabolism, include an increase in the activity of the hypothalamic-pituitary-thyroid (HPT) axis. Therefore, it remains a relevant task to explore the balance of thyroid hormones (THs), expression and activity of enzymes responsible for their synthesis in the thyroid gland (TG), expression of the main components of the HPT axis, as well as to investigate the effect of thyroid stimulating hormone (TSH) receptor antagonists on these indices when administered to animals exposed to cold. This work was aimed to study blood TSH and TH levels and the expression of hypothalamic, pituitary and thyroid genes involved in their synthesis and secretion in male rats exposed to low temperatures (5°C) for 10 days, as well as to assess the effect of a single treatment of animals with the thieno[2,3-d]-pyrimidine derivative TPY1, an original allosteric TSH receptor antagonist, on these indices. Cold-exposed rats developed T3 hyperthyroidism, which was associated with a decrease in the thyroxine level due to an increase in its conversion to T3, as indicated by an increase in the T3/T4 ratio and type 2 deiodinase (DIO2) expression in the TG. Compared to controls, the expression of thyroidal Tg and Nis genes, encoding thyroglobulin and Na+/I– symporter, increased in the TG of hyperthyroid rats. TPY1 normalized the T3 level and decreased Tg and Nis expression, suggesting a TPY1-induced decrease in the TSH-stimulated TSH receptor activity. TPY1 also increased the gene expression of the TSH β-subunit and thyroliberin receptor genes in the pituitary gland, which may be due to a higher threshold of sensitivity of thyrotrophs to the inhibitory effect of T3 under conditions of long-term T3 hyperthyroidism. A distinctive feature of cold-induced T3 hyperthyroidism in rats was the tissue specificity of changes in DIO2 gene expression, namely its increase in the TG and a decrease in the hypothalamus, as well as the retention of elevated DIO2 gene expression in the TG after TPY1 treatment. Thus, prolonged exposure of rats to cold leads to the development of pronounced T3 hyperthyroidism with increased expression of genes responsible for TH synthesis, while the treatment with an allosteric TSH receptor antagonist significantly normalizes these indices. [ABSTRACT FROM AUTHOR]

Background: Our study focuses on Yakutian cattle, a Siberian native breed, examining its inbreeding and diversity through genome-wide analysis of runs of homozygosity (ROHs). Yakutian cattle are adapted to Siberia's harsh sub-arctic conditions, enduring temperatures below −70°C. However, the population genetics studies on this breed are scanty, to document the genetic uniqueness in these cattle. Results: We analyzed 40 Yakutian cattle with strict quality control for ROH detection yielding 683 homozygous segments, averaging 17 per individual with an average length of 9 Mb. ROH regions were found to be involved in important pathways pertaining to cold adaptation. Autozygosity ranged from 1% to 12% of the genome, with a relatively low average inbreeding coefficient (FROH) of 0.057, as compared to other breeds. Also, the different diversity indicators, namely, principal component analysis, heterozygosity, and effective population size analysis, revealed the prevalence of genetic diversity within the breed. Conclusion: Our findings on ROH are the first of its kind in Yakutian cattle that support their adaptability to colder environments, as evidenced by low inbreeding and high genetic diversity. [ABSTRACT FROM AUTHOR]

Understanding the genomic architecture of temperature adaptation is critical for characterizing and predicting the effects of temperature changes on natural populations. However, our understanding of these mechanisms is still limited, especially concerning adaptation to a cold climate. Here, we looked for adaptive phenotypic features that may help high‐elevation waterflea (Daphnia sinensis) clones to cope with the low temperatures of the Qinghai–Tibetan Plateau (QTP) and explored possible genomic signatures of adaptation to cold. We used an experimental approach to compare transcriptional responses, in high‐elevation and lowland D. sinensis ecotypes from China to different experimental temperatures (16°C vs. 20°C). We ran life table experiments and found that high‐elevation clones (from the QTP) produced more offspring in their 1st clutch (or over the 1st two clutches) than lowland clones when grown at a lower temperature. This temperature‐dependent life history difference was associated with strong genomic signatures of temperature adaptation: the gene SLC4A11 (encoding a transmembrane protein transporting Na+ and H+), together with its encompassing genomic island, might contribute to the adaptive evolution to the cold temperature experienced by high‐elevation clones. We noted that a set of candidate genes specific to the high‐elevation clones was associated with lipid metabolism, cuticle production, and cellular proliferation, possibly involved in the mechanism of temperature adaptation of these clones to the climate on the QTP. Our findings advance the understanding of how organisms have evolved to cope with cold environments. [ABSTRACT FROM AUTHOR]

Simple Summary: This study examined the transcriptome and physiological responses of cold-tolerant soybean cultivar "KD52" and cold-sensitive cultivar "DS17". Increased malondialdehyde levels demonstrated DS17's vulnerability to lipid peroxidation and membrane breakdown. In contrast, cold exposure boosted antioxidant enzyme activity in the KD52 cultivar, including peroxidase and superoxide dismutase, demonstrating a strong antioxidant defense system against oxidative stress. A transcriptomic study mapped 54,532 genes and showed dynamic responses. This group had 234 differentially expressed genes (DEGs) that consistently changed over time, indicating unique expression patterns in the 2 cultivars. These key DEGs and physiological markers were linked to candidate genes for oxidative damage management and antioxidant defenses. The identification of improved defense mechanisms in KD52 and key genes should improve soybean cold stress tolerance. Low temperatures greatly restrict the development, growth, and productivity of soybeans, with their effects differing across various cultivars. The present work investigated the transcriptome and physiological reactions of two soybean cultivars, namely "KD52" exhibiting cold tolerance and "DS17" displaying cold sensitivity, to cold stress across a precisely defined period. The soybean plants were subjected to cold treatment at 6 °C for durations of 0, 2, 4, and 8 h. A comparative physiological marker study revealed distinct reactions to cold stress in the two cultivars. The findings showed that increased malondialdehyde levels provided evidence of DS17's heightened vulnerability to lipid peroxidation and membrane degradation. In contrast, the KD52 cultivar exhibited increased activities of antioxidant enzymes, including peroxidase and superoxide dismutase, in response to cold exposure, suggesting a strong antioxidant defense system against oxidative stress. The transcriptomic analysis revealed dynamic responses, mapping 54,532 genes. Within this group, a total of 234 differentially expressed genes (DEGs) were found to be consistently changed at several time intervals, showing unique expression patterns across the two cultivars. Analysis of the association between these important DEGs and the physiological indicators revealed candidate genes that may be involved in controlling oxidative damage and antioxidant defenses. Some key genes showed a progressive rise in expression over time in both cultivars, with a more significant acceleration in KD52, and are probably involved in promoting adaptation processes during extended periods of cold exposure. The identification of improved defense mechanisms in KD52, together with the identification of crucial genes, offers great prospects for enhancing the cold stress resilience of soybean. [ABSTRACT FROM AUTHOR]

Although traditionally considered pristine, Antarctica faces an increasing threat of antibiotic resistance due to human intervention. Here, we obtained a bacterial isolate, the CAS19 strain, from a lake water sample from Ardley Island, Antarctica and characterized it comprehensively. The CAS19 was a psychrotrophic and neutrophilic/alkalitolerant bacterium thriving at temperatures from 15 to 33 °C and pH levels from 6.0 to 9.0. Besides the production of siderophore and indole acetic acid, it also exhibited proteolytic and lipolytic activities. It was identified as Pseudomonas migulae by multilocus (16S rRNA, gyrB, rpoB and rpoD) sequence analysis, and its genome was 6.5 Mbps in length, had 59% GC content, and contained 5,821 coding sequences. The CAS19 was resistant to several antibiotics, including trimethoprim, penicillin, vancomycin, and erythromycin, confirmed by RT-qPCR analysis, with a notable increase in dfr (63-fold), bla (461-fold), vanW (31.7-fold) and macA (24.7-fold) expressions upon antibiotic exposure. Additionally, CAS19 exhibited resistance to heavy metals with an order of Cr(III) = Cu(II) > Ni(II) > Zn(II) > Cd(II), and showed diesel fuel (5%) degradation capacity. Cold-related genes cspA_2 and cspD were overexpressed at 4 and 15 °C, consistent with the cold adaptation mechanism. In conclusion, for the first time an Antarctic P. migulae isolate has been characterized in detail, uncovering a rich resistome repertoir that might be associated with anthropogenic disturbances. [ABSTRACT FROM AUTHOR]

With global climate change, ecosystems are affected, some of which are more vulnerable than others, such as alpine ecosystems. Microbes play an important role in environmental change in global ecosystems. Plants and microbes are tightly associated, and symbiotic or commensal microorganisms are crucial for plants to respond to stress, particularly for alpine plants. The current study of alpine and subalpine plant microbiome only stays at the community structure scale, but its ecological function and mechanism to help plants to adapt to the harsh environments have not received enough attention. Therefore, it is essential to systematically understand the structure, functions and mechanisms of the microbial community of alpine and subalpine plants, which will be helpful for the conservation of alpine and subalpine plants using synthetic microbial communities in the future. This review mainly summarizes the research progress of the alpine plant microbiome and its mediating mechanism of plant cold adaptation from the following three perspectives: (1) Microbiome community structure and their unique taxa of alpine and subalpine plants; (2) The role of alpine and subalpine plant microbiome in plant adaptation to cold stress; (3) Mechanisms by which the microbiome of alpine and subalpine plants promotes plant adaptation to low-temperature environments. Finally, we also discussed the future application of high-throughput technologies in the development of microbial communities for alpine and subalpine plants. The existing knowledge could improve our understanding of the important role of microbes in plant adaptation to harsh environments. In addition, perspective further studies on microbes' function confirmation and microbial manipulations in microbiome engineering were also discussed. [ABSTRACT FROM AUTHOR]

Sorghum is a crop that is susceptible to low temperatures. However, due to the extreme global temperatures, new genotypes have been bred to adapt better to cold climates. Therefore, to better understand the metabolic and molecular differences that may contribute to the improved cold tolerance of these genotypes, it is essential to investigate whether specific molecules play a key role in determining the degree of sorghum tolerance. Furthermore, identifying genes associated with cold tolerance may assist in the development of more robust and productive sorghum cultivars. Here, we analysed the changes in selected elements of the antioxidant metabolism, genes, and miRNAs in two sorghum varieties with different degrees of tolerance to cold stress at different times of exposure to cold stress. The high expression of SbCBF6 in response to cold treatment in early time in the tolerant variety suggests its involvement in the cold response, thereby facilitating a better adaptation of the plant to cold conditions. MiR398 and miR394 showed contrasting behaviour in both varieties in low temperatures, resulting in interesting miRNAs in the degree of sorghum tolerance. MiR319, a marker for the selection of cold‐tolerant cultivars, presents a decrease, suggesting that the better capacity to repress the expression of several members of TCP family of transcription factor genes might be involved in better tolerance to cold stress. This study shows the changes of molecules of interest in response to cold stress in sorghum, marking the difference between cold‐susceptible and cold‐tolerant sorghum plants, which can contribute to selecting tolerant genotypes, allowing new strategies to enhance crop productivity and food security, in regions where low temperatures significantly constrain crop growth and yield. [ABSTRACT FROM AUTHOR]

In the present review, we summarize genome mining of genomic data obtained from the psychrophilic Antarctic marine ciliate Euplotes focardii and its evolutionary-close mesophilic cosmopolitan counterpart E. crassus. This analysis highlights adaptation strategies that are unique to the Antarctic ciliate, including antioxidant gene duplication and distinctive substitutions that may play roles in increased drug binding affinity and enzyme reaction rate in cold environments. Enzymes from psychrophiles are usually characterized by high activities and reaction rates at low temperatures compared with their counterparts from mesophiles and thermophiles. As a rule, catalyst cold activity derives from an increased structural flexibility that may lead to protein denaturation in response to temperature fluctuation. Molecular thermolability has been a major drawback of using macromolecules from psychrophiles in industrial applications. Here, we report a case study in which the role of peculiar amino acid substitution in cold adaptation is demonstrated by site-directed mutagenesis. Combined with a rational design approach, these substitutions can be used for site-directed mutagenesis to obtain cold-active catalysts that are structurally stable. Furthermore, molecular docking analysis of β-tubulin isotypes extrapolated from E. focardii and E. crassus genomes allowed us to obtain additional insight on the taxol binding site and drug affinity. E. focardii genome mining and the comparison with the mesophilic sibling counterpart can be used as an inspiration for molecular engineering for medical and industrial applications. [ABSTRACT FROM AUTHOR]

Background. In many studies over the past decade, scientists have made a connection between the composition of gut microbiota and human health. A number of publications have shown that gut bacteria are involved in many metabolic and physiological processes of the organism. The composition of the gut microbiome is unique for each person and is formed under the influence of various factors associated with both the individual characteristics of the body and the characteristics of the environment. Different regional characteristics make it necessary for the body to adapt to certain conditions, including temperature fluctuations. Living in areas with low temperatures, such as the Arctic zone, dictates the need for increased energy consumption, which affects the composition of the gut microbiome. Methods. In our study, an extensive questionnaire was conducted among the participants, where many questions were included about the dietary preferences of the study participants, which allowed them us to further divide them into groups according to their diets. Stool samples were collected from participants from 3 groups: Arctic native, Arctic newcomer and the control group. The next step was the isolation of bacterial DNA and sequencing the 16S rRNA gene. The analysis of the results of the diversity of the intestinal microbiota was carried out both with and without taking into account the dietary preferences of the participants. Results. As a result of comparing the intestinal microbiota obtained from residents of the Arctic zone with the gut microbiota of residents of other regions with a milder climate, significant differences are found. These differences may be related to limited food resources and a reduction in the variety of food products characteristic of this Arctic region. t was also found that representatives of the bacterial families Christensenellaceae and Muribaculaceae dominated the control group, both with traditional nutrition and with a dairy-free diet in comparison with the Arctic groups. The control group was dominated by representatives of the Prevotellaceae, Enterobacteriaceae and Comamonadaceae families compared to the Arctic group (with a traditional diet). The results also show that the number of representatives of the families Desulfovibrionaceae (with traditional diet) and Enterobacteriaceae (with milk-free diet) is growing in the Arctic group. Conclusions. In the course of this work, bacterial families characteristic of people living in the Arc-tic zone of the Far Eastern region of the Russian Federation were identified. Poor diet, difficult climatic conditions, and problems with logistics and medical care can have a strong impact on the health of this population. The main type of diet for the inhabitants of the Arctic is the traditional type of diet. They consume a large number of low-cost products, obtainget animal protein from poultry and canned food, and also eat a small number of fresh vegetables and fruits. Such a diet is due to the social status of the study participants and the climatic and geographical features of the region (difficulties in agriculture). With such a diet, we observe a decrease in representatives of the Christensenellaceae, Muribaculaceae, Eubacteriaceae, and Prevotellaceae families and an increase in representatives of the Enterobacteriaceae and Desulfovibrionaceae families among Arctic residents. This imbalance in the futuremay cause, this population may to develop various diseases in the future, including chronic diseases such as obesity, intestinal dysbiosis, inflammatory bowel diseases, and type 2 diabetes. [ABSTRACT FROM AUTHOR]

Numerous psychrophiles inhabit the cold environments that are prevalent across the global biosphere. The adaptation of psychrophiles to cold conditions has been widely studied in strains from the archaeal phylum Euryarchaeota and the bacterial class Gamma-proteobacteria. However, given the vast diversity of microorganisms in cold environments, many microbial lineages with potentially unique cold-adaptation strategies remain largely unexplored. This study investigates the cold responses of the Antarctic strain Poseidonibacter antarcticus SM1702T, a cold-adapted bacterium belonging to the class Epsilon-proteobacteria within the phylum Campylobacterota. Proteomic analysis revealed that this strain responds to low temperatures by overexpressing proteins involved in energy production and amino acid transport. Experimental results confirmed that intracellular ATP concentrations increased at low temperatures compared to higher temperatures. Low temperatures significantly reduced the strain’s amino acid absorption rates, a condition that was mitigated by increased expression of membrane transporters. We propose that the impairment of membrane protein function due to low temperatures is the primary factor affecting cell growth. As a result, the strain enhances ATP synthesis and upregulates membrane transporter expression to counteract cold stress. These findings contribute to a deeper understanding of cold adaptation strategies in psychrophiles. [ABSTRACT FROM AUTHOR]

Numerous psychrophiles inhabit the cold environments that are prevalent across the global biosphere. The adaptation of psychrophiles to cold conditions has been widely studied in strains from the archaeal phylum Euryarchaeota and the bacterial class Gamma-proteobacteria. However, given the vast diversity of microorganisms in cold environments, many microbial lineages with potentially unique cold-adaptation strategies remain largely unexplored. This study investigates the cold responses of the Antarctic strain Poseidonibacter antarcticus SM1702T, a cold-adapted bacterium belonging to the class Epsilon-proteobacteria within the phylum Campylobacterota. Proteomic analysis revealed that this strain responds to low temperatures by overexpressing proteins involved in energy production and amino acid transport. Experimental results confirmed that intracellular ATP concentrations increased at low temperatures compared to higher temperatures. Low temperatures significantly reduced the strain’s amino acid absorption rates, a condition that was mitigated by increased expression of membrane transporters. We propose that the impairment of membrane protein function due to low temperatures is the primary factor affecting cell growth. As a result, the strain enhances ATP synthesis and upregulates membrane transporter expression to counteract cold stress. These findings contribute to a deeper understanding of cold adaptation strategies in psychrophiles. [ABSTRACT FROM AUTHOR]

In China, the red swamp crayfish (Procambarus clarkii), a notorious invasive species, has become an important economic freshwater species. In order to compare the genetic diversity and population structure of crayfish from northern and southern China, we collected 60 crayfish individuals from 4 crayfish populations in northern China and 2 populations in southern China for sequencing using the 2b-RAD technique. Additionally, the whole genome sequence information obtained by 2b-RAD of 90 individuals from 2 populations in northern China and 7 populations in southern China were downloaded from NCBI. After quality control, a total of 25,371 SNPs were detected from approximately 54.22 billion raw reads. Based on these SNPs, high genetic diversity was observed in the 15 crayfish populations in China. The pairwise FST values indicated that there was a large genetic differentiation of crayfish populations in northern and southern China. Despite common genetic backgrounds, due to geographical barriers, genetic divergence has been observed in northern and southern China crayfishes. The principal component analysis in combination with Admixture and Neighbor-Joining tree analysis showed that the crayfish fell into two clusters corresponding to geographical regions. The integrated analysis of whole genome and transcriptome data showed that two genes (CETN4 and CPEB2) might play important roles during crayfish resistance to a cold environment. This study reveals the genetic differentiation of crayfish populations in northern and southern China and provides clues to the genetic mechanism related to cold adaptation. [ABSTRACT FROM AUTHOR]

Abstract Background Substantial discoveries during the past century have revealed that transposable elements (TEs) can play a crucial role in genome evolution by affecting gene expression and inducing genetic rearrangements, among other molecular and structural effects. Yet, our knowledge on the role of TEs in adaptation to extreme climates is still at its infancy. The availability of long-read sequencing has opened up the possibility to identify and study potential functional effects of TEs with higher precision. In this work, we used Drosophila montana as a model for cold-adapted organisms to study the association between TEs and adaptation to harsh climates. Results Using the PacBio long-read sequencing technique, we de novo identified and manually curated TE sequences in five Drosophila montana genomes from eco-geographically distinct populations. We identified 489 new TE consensus sequences which represented 92% of the total TE consensus in D. montana. Overall, 11–13% of the D. montana genome is occupied by TEs, which as expected are non-randomly distributed across the genome. We identified five potentially active TE families, most of them from the retrotransposon class of TEs. Additionally, we found TEs present in the five analyzed genomes that were located nearby previously identified cold tolerant genes. Some of these TEs contain promoter elements and transcription binding sites. Finally, we detected TEs nearby fixed and polymorphic inversion breakpoints. Conclusions Our research revealed a significant number of newly identified TE consensus sequences in the genome of D. montana, suggesting that non-model species should be studied to get a comprehensive view of the TE repertoire in Drosophila species and beyond. Genome annotations with the new D. montana library allowed us to identify TEs located nearby cold tolerant genes, and present at high population frequencies, that contain regulatory regions and are thus good candidates to play a role in D. montana cold stress response. Finally, our annotations also allow us to identify for the first time TEs present in the breakpoints of three D. montana inversions.

Abstract Background Adaptation to cold was essential for human migration across Eurasia. Non-shivering thermogenesis through brown adipose tissue (BAT) participates in cold adaptation because some genes involved in the differentiation and function of BAT exhibit signatures of positive natural selection in populations at high latitudes. Whether these genes are associated with the inter-individual variability in BAT thermogenesis remains unclear. In this study, we evaluated the potential associations between BAT activity and single nucleotide polymorphisms (SNPs) in candidate gene regions in East Asian populations. Methods BAT activity induced by mild cold exposure was measured in 399 healthy Japanese men and women using fluorodeoxyglucose-positron emission tomography and computed tomography (FDG-PET/CT). The capacity for cold-induced thermogenesis and fat oxidation was measured in 56 men. Association analyses with physiological traits were performed for 11 SNPs at six loci (LEPR, ANGPTL8, PLA2G2A, PLIN1, TBX15-WARS2, and FADS1) reported to be under positive natural selection. Associations found in the FDG-PET/CT population were further validated in 84 healthy East Asian men and women, in whom BAT activity was measured using infrared thermography. Associations between the SNP genotypes and BAT activity or other related traits were tested using multiple logistic and linear regression models. Results Of the 11 putative adaptive alleles of the six genes, two intronic SNPs in LEPR (rs1022981 and rs12405556) tended to be associated with higher BAT activity. However, these did not survive multiple test comparisons. Associations with lower body fat percentage, plasma triglyceride, insulin, and HOMA-IR levels were observed in the FDG-PET/CT population (P

Species of Antarctomyces and Thelebolus (Thelebolaceae), primarily found in Antarctic environments, exhibit psychrophilic adaptations, yet their mitochondrial genomes have not been extensively studied. Furthermore, few studies have compared the mitochondrial genomes of psychrophilic, psychrotrophic, and mesophilic fungi. After successful sequencing and assembly, this study annotated the mitochondrial genomes of Antarctomyces psychrotrophicus CPCC 401038 and Thelebolus microsporus CPCC 401041. We also performed a comparative analysis with the previously characterized mitochondrial genomes of psychrotrophic and mesophilic fungi. The analysis revealed that nad4L was the most conserved gene across the mitochondrial genomes, characterized by its synonymous and non-synonymous substitution rates (Ks and Ka), genetic distance, and GC content and skew within the protein-coding genes (PCGs). Additionally, the mitochondrial genomes of psychrophilic and psychrotrophic fungi showed a higher proportion of protein-coding regions and a lower GC content compared to those of mesophilic fungi, underscoring the genetic basis of cold adaptation. Phylogenetic analyses based on these mitochondrial genes also confirmed the phylogenetic relationships of Thelebolaceae in the class Leotiomycetes. These findings advance our understanding of the phylogenetic relationships and evolutionary dynamics within the family Thelebolaceae, highlighting how different environmental temperatures influence fungal mitochondrial genomic structure and adaptation. [ABSTRACT FROM AUTHOR]

Introduction: Microalgae, known for their adaptability to extreme environments, are important for basic research and industrial applications. Euglena, unique for its lack of a cell wall, has garnered attention due to its versatility and the presence of bioactive compounds. Despite its potential, few studies have focused on Euglena’s cold adaptation mechanisms. Methods: This study investigates the cold adaptation mechanisms of Euglena gracilis, a microalga found in highly diverse environmental habitats, by comparing its growth, photosynthetic performance, and physiological and biochemical responses under two low-temperature cultivation modes: pre-adaptation to 16°C followed by exposure to 4°C (PreC) and direct exposure to 4°C (DirC). Results and discussion: In this study, the PreC group exhibited superior growth rates, higher photosynthetic efficiency, and more excellent antioxidant activity compared to the DirC group. These advantages were attributed to higher levels of protective compounds, enhanced membrane stability, and increased unsaturated fatty acid content. The PreC group’s ability to maintain higher cell vitality under cold stress conditions underscores the significance of pre-adaptation in enhancing cold tolerance. The findings from this research provide valuable insights into the mechanisms underlying cold adaptation in E. gracilis, emphasizing the benefits of pre-adaptation. These insights are crucial for optimizing the cultivation of algal species under cold stress conditions, which is essential for both biotechnological applications and ecological studies. This study not only advances our understanding of Euglena’s adaptive responses to low temperatures but also contributes to the broader field of algal research and its industrial exploitation. [ABSTRACT FROM AUTHOR]

Background: The deep-sea cold seep zone is characterized by high pressure, low temperature, darkness, and oligotrophy. Vesicomyidae clams are the dominant species within this environment, often forming symbiotic relationships with chemosynthetic microbes. Understanding the mechanisms by which Vesicomyidae clams adapt to the cold seep environment is significant. Acetylation modification of lysine is known to play a crucial role in various metabolic processes. Consequently, investigating the role of lysine acetylation in the adaptation of Vesicomyidae clams to deep-sea environments is worthwhile. So, a comparative study of lysine acetylation in cold seep clam Archivesica marissinica and shallow water shellfish Ruditapes philippinarum was conducted. Results: A total of 539 acetylated proteins were identified with 1634 acetylation sites. Conservative motif enrichment analysis revealed that the motifs -KacR-, -KacT-, and -KacF- were the most conserved. Subsequent gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) enrichment analyses were conducted on significantly differentially expressed acetylated proteins. The GO enrichment analysis indicated that acetylated proteins are crucial in various biological processes, including cellular response to stimulation, and other cellular processes (p < 0.05 and false discovery rate (FDR) < 0.25). The results of KEGG enrichment analysis indicated that acetylated proteins are involved in various cellular processes, including tight junction, motor proteins, gap junction, phagosome, cGMP-PKG signaling pathways, endocytosis, glycolysis/gluconeogenesis, among others (p < 0.05 and FDR < 0.25). Notably, a high abundance of lysine acetylation was observed in the glycolysis/glycogenesis pathways, and the acetylation of glyceraldehyde 3-phosphate dehydrogenase might facilitate ATP production. Subsequent investigation into acetylation modifications associated with deep-sea adaptation revealed the specific identification of key acetylated proteins. Among these, the adaptation of cold seep clam hemoglobin and heat shock protein to high hydrostatic pressure and low temperature might involve an increase in acetylation levels. Acetylation of arginine kinase might be related to ATP production and interaction with symbiotic bacteria. Myosin heavy chain (Ama01085) has the most acetylation sites and might improve the actomyosin system stability through acetylation. Further validation is required for the acetylation modification from Vesicomyidae clams. Conclusion: A novel comparative analysis was undertaken to investigate the acetylation of lysine in Vesicomyidae clams, yielding novel insights into the regulatory role of lysine acetylation in deep-sea organisms. The findings present many potential proteins for further exploration of acetylation functions in cold seep clams and other deep-sea mollusks. [ABSTRACT FROM AUTHOR]

ABSTRACT Environmental temperatures directly affect physiological rates in ectotherms by constraining the possible body temperatures they can achieve, with physiological processes slowing as temperatures decrease and accelerating as temperatures increase. As environmental constraints increase, as they do northward along the latitudinal thermal gradient, organisms must adapt to compensate for the slower physiological processes or decreased opportunity time. Evolving faster general metabolic rates is one adaptive response posited by the metabolic cold adaptation (MCA) hypothesis. Here we test the MCA hypothesis by examining metabolism of prairie lizard populations across the latitudinal thermal gradient. Our results show that populations from cooler environments have higher standard metabolic rates (SMRs), but these are explained by associated larger body sizes. However, metabolic rates of fed, postprandial individuals (MRFed) and metabolic energy allocated to digestion (MRΔ) were highest in the population from the coldest environment after accounting for the effect of body size. Our results suggest cold‐adapted populations compensate for lower temperatures and shorter activity periods by increasing metabolic rates associated with physiological processes and thus support the MCA hypothesis. When examining energy expenditure, metabolic rates of individuals in a postprandial state (MRFed) may be more ecologically relevant than those in a postabsorptive state (SMR) and give a better picture of energy use in ectotherm populations. [ABSTRACT FROM AUTHOR]

Russian Snow White (RSW) chickens are characterized by high egg production, extreme resistance to low temperatures, disease resistance, and by the snow-white color of the day-old chicks. Studying the genome of this unique chicken breed will reveal its evolutionary history and help to understand the molecular genetic mechanisms underlying the unique characteristics of this breed, which will open new breeding opportunities and support future studies. We have sequenced and made a de novo assembly of the whole RSW genome using deep sequencing (250×) by the short reads. The genome consists of 40 chromosomes with a total length of 1.1 billion nucleotide pairs. Phylogenetic analysis placed the RSW near the White Leghorn, Fayoumi, and Houdan breeds. Comparison with other chicken breeds revealed a wide pool of mutations unique to the RSW. The functional annotation of these mutations showed the adaptation of genes associated with the development of the nervous system, thermoreceptors, purine receptors, and the TGF-beta pathway, probably caused by selection for low temperatures. We also found adaptation of the immune system genes, likely driven by selection for resistance to viral diseases. Integration with previous genome-wide association studies (GWAS) suggested several causal single nucleotide polymorphisms (SNPs). Specifically, we identified an RSW-specific missense mutation in the RALYL gene, presumably causing the snow-white color of the day-old chicks, and an RSW-specific missense mutation in the TLL1 gene, presumably affecting the egg weight. [ABSTRACT FROM AUTHOR]

ABSTRACT Gene expression can accelerate ecological divergence by rapidly tweaking the response of an organism to novel environments, with more divergent environments exerting stronger selection and supposedly, requiring faster adaptive responses. Organisms adapted to extreme environments provide ideal systems to test this hypothesis, particularly when compared to related species with milder ecological niches. The Emperor penguin (Aptenodytes forsteri) is the only endothermic vertebrate breeding in the harsh Antarctic winter, in stark contrast with the less cold‐adapted sister species, the King penguin (A. patagonicus). Assembling the first de novo transcriptomes and analysing multi‐tissue (brain, kidney, liver, muscle, skin) RNA‐Seq data from natural populations of both species, we quantified the shifts in tissue‐enhanced genes, co‐expression gene networks, and differentially expressed genes characterising Emperor penguin adaptation to the extreme Antarctic. Our analyses revealed the crucial role played by muscle and liver in temperature homeostasis, fasting, and whole‐body energy metabolism (glucose/insulin regulation, lipid metabolism, fatty acid beta‐oxidation, and blood coagulation). Repatterning at the regulatory level appears as more important in the brain of the Emperor penguin, showing the lowest signature of differential gene expression, but the largest co‐expression gene network shift. Nevertheless, over‐expressed genes related to mTOR signalling in the brain and the liver support their central role in cold and fasting responses. Besides contributing to understanding the genetics underlying complex traits, like body energy reservoir management, our results provide a first insight into the role of gene expression in adaptation to one of the most extreme environmental conditions endured by an endotherm. [ABSTRACT FROM AUTHOR]

Weight and skin-fold measurements were made at five-day intervals during a 47-day expedition by six men and three women from the edge of the sea ice to the South Pole. From these, together with detailed manual records of the nutrition for individual participants, the average daily energy expenditure was determined before and after a resupply at approximately mid-point of the expedition. For all participants body weight fell during the expedition with the overall loss being much smaller for the three female participants (-4.0, -4.0, -4.4kg) than for the male participants, (mean±sd) -8.6±2.0kg. Fat weight fell approximately linearly during the expedition with a total loss of (-4.1, -6.5 and -2.5kg) for the three female participants and -6.8±1.7kg for the male participants. Individual fat-free weight changed by a smaller amount overall: (0.13, 2.5 and -1.8kg) for the three female participants; -1.8±2.0kg for the male participants who, with one exception, lost fat-free tissue All participants showed a substantial variation in fat-free tissue weight during the expedition. Analysis of the daily energy expenditure showed adequate nutrition but the intake fell for the second part of the expedition although the reasons for this are unclear, but adaptation to the cold, altitude and workload are possible explanations. The validity of this time-averaged measurement for individual participants was determined from analysing moments about the mean of time-series actigraphy data from wrist worn devices. The mean and autocorrelation function of the actigraphy data across subjects were analysed to determine whether measures could be compared between participants. The first, second and third moment about the mean of the day-to-day activity was found to be time-invariant for individual subjects (χ2, p>0.05) and the normalized mean and autocorrelation measured over a day for each participant indistinguishable from the mean of the group (χ2, p>0.05) allowing both longitudinal and cross-sectional analysis. [ABSTRACT FROM AUTHOR]

Translation, a fundamental process regulating cellular growth and proliferation, relies on functional ribosomes. As sessile organisms, plants have evolved adaptive strategies to maintain a delicate balance between growth and stress response. But the underlying mechanisms, particularly on the translational level, remain less understood. In this study, we revealed the mechanisms of AtPRMT3-RPS2B in orchestrating ribosome assembly and managing translational regulation. Through a forward genetic screen, we identified PDCD2-D1 as a suppressor gene restoring abnormal development and ribosome biogenesis in atprmt3-2 mutants. Our findings confirmed that PDCD2 interacts with AtPRMT3-RPS2B, and facilitates pre-ribosome transport through nuclear pore complex, finally ensuring normal ribosome translation in the cytoplasm. Additionally, the dysfunction of AtPRMT3-RPS2B was found to enhance freezing tolerance. Moreover, we revealed that AtPRMT3-RPS2B promotes the translation of housekeeping mRNAs while concurrently repressing stress-related mRNAs. In summary, our study sheds light on the regulatory roles of AtPRMT3-RPS2B in ribosome assembly and translational balance, enabling the trade-off between growth and stress. Ribosome biogenesis and translation are essential processes for cellular activity. Here, the authors illustrated the role of AtPRMT3-RPS2B in maintaining ribosome assembly and coordinating growth-stress trade-off. [ABSTRACT FROM AUTHOR]

Antarctica is characterized by extreme cold, isolated, and unique ecosystems. Nevertheless, Antarctica harbors diverse species of microorganisms, particularly in its ice-covered lakes and subglacial environments. These microorganisms have special adaptations to extreme cold and low-nutrient conditions. Some extremophiles, like psychrophiles can thrive in these harsh environments. Phenoliferia glacialis USM-PSY62, previously identified as Rhodotorula sp. USM-PSY62 is a psychrophilic yeast isolated from the ice brine of Antarctica. However, there is very little information on this psychrophilic yeast. This study aims to characterize the P. glacialis USM-PSY62 through the identification of the optimum growth parameters in different media (Yeast Peptone Dextrose, YPD & Yeast Malt, YM), temperature (4°C, 15°C, 20°C) and pH (6, 7, 8, 9) as well as their ability in carbon assimilation and extracellular enzyme production. It has an optimal growth in YPD compared to YM broth media. P. glacialis USM-PSY62 grows optimally at 15°C and pH 7.0. This Antarctic yeast enters the stationary phase on day six of incubation under optimum conditions. It appeared mainly as elongated-shape and oval-shaped with budding formation and was found to produce extracellular enzymes such as protease and amylase in the presence of 2% glucose concentration in YM media. P. glacialis USM-PSY62 also can assimilate various types of carbon sources including raffinose, arabinose, and maltose. Interestingly, the psychrophilic yeast presented growth in media supplemented with Persistent Organic Pollutants (POPs) such as dichlorophenyldichloroethylene (DDE) and polychlorinated biphenyl (PCB). These preliminary findings suggest that P. glacialis USM-PSY62 has tremendous potential for bioremediation application in polluted cold regions, as well as deepening our knowledge of its optimal growth conditions. [ABSTRACT FROM AUTHOR]

Allotetraploid white clover (Trifolium repens) formed during the last glaciation through hybridisation of two European diploid progenitors from restricted niches: one coastal, the other alpine. Here, we examine which hybridisation‐derived molecular events may have underpinned white clover's postglacial niche expansion. We compared the transcriptomic frost responses of white clovers (an inbred line and an alpine‐adapted ecotype), extant descendants of its progenitor species and a resynthesised white clover neopolyploid to identify genes that were exclusively frost‐induced in the alpine progenitor and its derived subgenomes. From these analyses we identified galactinol synthase, the rate‐limiting enzyme in biosynthesis of the cryoprotectant raffinose, and found that the extant descendants of the alpine progenitor as well as the neopolyploid white clover rapidly accumulated significantly more galactinol and raffinose than the coastal progenitor under cold stress. The frost‐induced galactinol synthase expression and rapid raffinose accumulation derived from the alpine progenitor likely provided an advantage during early postglacial colonisation for white clover compared to its coastal progenitor. Summary statement: Cold induction of galactinol synthase expression and raffinose accumulation are likely alpine progenitor‐derived traits contributing to postglacial niche expansion in allotetraploid white clover. [ABSTRACT FROM AUTHOR]

Background: Substantial discoveries during the past century have revealed that transposable elements (TEs) can play a crucial role in genome evolution by affecting gene expression and inducing genetic rearrangements, among other molecular and structural effects. Yet, our knowledge on the role of TEs in adaptation to extreme climates is still at its infancy. The availability of long-read sequencing has opened up the possibility to identify and study potential functional effects of TEs with higher precision. In this work, we used Drosophila montana as a model for cold-adapted organisms to study the association between TEs and adaptation to harsh climates. Results: Using the PacBio long-read sequencing technique, we de novo identified and manually curated TE sequences in five Drosophila montana genomes from eco-geographically distinct populations. We identified 489 new TE consensus sequences which represented 92% of the total TE consensus in D. montana. Overall, 11–13% of the D. montana genome is occupied by TEs, which as expected are non-randomly distributed across the genome. We identified five potentially active TE families, most of them from the retrotransposon class of TEs. Additionally, we found TEs present in the five analyzed genomes that were located nearby previously identified cold tolerant genes. Some of these TEs contain promoter elements and transcription binding sites. Finally, we detected TEs nearby fixed and polymorphic inversion breakpoints. Conclusions: Our research revealed a significant number of newly identified TE consensus sequences in the genome of D. montana, suggesting that non-model species should be studied to get a comprehensive view of the TE repertoire in Drosophila species and beyond. Genome annotations with the new D. montana library allowed us to identify TEs located nearby cold tolerant genes, and present at high population frequencies, that contain regulatory regions and are thus good candidates to play a role in D. montana cold stress response. Finally, our annotations also allow us to identify for the first time TEs present in the breakpoints of three D. montana inversions. [ABSTRACT FROM AUTHOR]

Juniperus L. is the second largest conifer genus, having the widest distribution of all conifer genera. However, its evolution in East Asia is unclear due to the scarce fossil records. We described a set of Juniperus fossils from the Early Miocene of Tiejianggou, Chifeng, Inner Mongolia. Although only two seed cones and five branch segments were preserved, the fossils were assigned to Juniperus chifengensis Liang Xiao et Liyan Guo sp. nov. (Cupressaceae). The diagnostic characteristics include leaves in a decussate or ternate arrangement, both scalelike and needle-like leaves on mature branchlets, scalelike leaves on juvenile branchlets, leaves with two stomatal bands adaxially and abaxially, terminal seed cones, and two or four seeds, which is the most similar extant species J. chinensis morphologically. However, the cuticle of the abaxial epidermis shows longer and more disordered cells. With a close affinity to the extant Juniperus chinensis, J. chifengensis, the macrofossil record of sect. Sabina (Juniperus) in East Asia, had existed in East Asia in the early Early Miocene. The longer abaxial epidermal cells confirm its adaptation to the dry and cold climate that occurred from the Early Miocene to the present. [ABSTRACT FROM AUTHOR]

The mammalian body possesses remarkable adaptability to cold exposure, involving intricate adjustments in cellular metabolism, ultimately leading to thermogenesis. However, cold‐induced stress can impact immune response, primarily through noradrenaline‐mediated pathways. In our study, we utilized a rat model subjected to short‐term or long‐term mild cold exposure to investigate systemic immune response during the cold acclimation. To provide human relevance, we included a group of regular cold swimmers in our study. Our research revealed complex relationship between cold exposure, neural signaling, immune response, and thermogenic regulation. One‐day cold exposure triggered stress response, including cytokine production in white adipose tissue, subsequently activating brown adipose tissue, and inducing thermogenesis. We further studied systemic immune response, including the proportion of leukocytes and cytokines production. Interestingly, γδ T cells emerged as possible regulators in the broader systemic response, suggesting their possible contribution in the dynamic process of cold adaptation. We employed RNA‐seq to gain further insights into the mechanisms by which γδ T cells participate in the response to cold. Additionally, we challenged rats exposed to cold with the Toll‐like receptor 2 agonist, showing significant modulation of immune response. These findings significantly contribute to understanding of the physiological acclimation that occur in response to cold exposure. [ABSTRACT FROM AUTHOR]

ABSTRACT Despite encroachment by agricultural systems and globalization, pastoral nomads maintain a robust presence in terms of numbers and subsistence activity. At the same time, increasing concern about climate change has promoted awareness that increased climatic fluctuation may push pastoral population past their capacity for resilience. The response of pastoralists to climate change has important implications for our evolutionary past and our increasingly problematic future. Yet, pastoralists have received less explicit attention than foragers as populations under consistent selective constraints including limited caloric intake, high levels of habitual activity, and high disease burdens. Additional factors include exposure to cold and high temperatures, as well as high altitude. Over the last 20 or so years, the use of new techniques for measuring energetics, including actigraphs and doubly labeled water have built on existing noninvasive sample collection for hormones, immune markers and genes to provide a more detailed picture of the human biology of pastoral populations. Here I consider recent work on pastoralists from Siberia and northern Europe, Africa, Asia, and South America. I survey what is known about maternal milk composition and infant health, childhood growth, lactase persistence, and adult energy expenditure and lactase persistence to build a picture of the pastoralist biological response to environmental conditions, including heat, cold, and high altitude. Where available I include information about population history because of its importance for selection. I end by outlining the impact of milk consumption and climate over the human life cycle and make suggestions for further research. [ABSTRACT FROM AUTHOR]