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Saliva-based RT-LAMP assays support heat shock protein 70 as a promising transcript marker for estrus identification in buffaloes.

Buffaloes do not exhibit overt estrus signs particularly during summer, leading to a significant economic loss to farmers. Previous studies have identified several candidate transcripts (HSP70, TIMP1, TLR4 and HSD17B1), abundant in buffalo saliva during estrus stage. However, there is no widely applicable technology for estrus detection targeting these transcripts. Therefore, the present study aimed to develop reverse transcription loop mediated isothermal amplification (RT-LAMP) assays for these candidate transcripts using buffalo saliva. Saliva samples were collected from 10 cyclic buffaloes and RT-LAMP assays were optimized for salivary RNA as well as direct saliva. Among the four candidate transcripts, HSP70 showed a statistically significant colour change (p-value = 0.0191) at the estrus stage compared to the diestrus stage. This abundance of HSP70 was also supported in large simulated population datasets (10,000 animals) generated using R. Further, the RT-LAMP assays were tested using direct saliva without RNA isolation, and the colour change in the samples during estrus suggested the feasibility of estrus identification using direct saliva, overcoming the tedious step of RNA isolation. The detection of HSP70 using either direct saliva or salivary RNA indicated its potential as a marker for estrus identification. Similarly, TLR4 appeared to be another potential biomarker for RT-LAMP reaction using direct saliva, but it needs further validation in both RNA and direct saliva samples. Overall, the proof-of-concept on RT-LAMP assays optimized for salivary transcripts in the present study would be useful for estrus identification in tropical production systems following further validation on a larger sample size.

Animals

Genome-wide identification of the HSP70 superfamily in tropical sea cucumber Stichopus monotuberculatus and their expression analysis under low-salinity stress.

Heat shock proteins (HSPs) are a group of evolutionarily conserved molecular chaperones that serve as indispensable core regulators in preserving cellular homeostasis and orchestrating organismal stress responses. The tropical sea cucumber Stichopus monotuberculatus, a high-value aquaculture species, is sensitive to fluctuations in environmental salinity-a challenge that has emerged as a critical bottleneck limiting its large-scale commercial cultivation. However, no systematic investigation has been conducted to characterize the HSP70 superfamily in S. monotuberculatus and elucidate its functional roles in salinity adaptation. In the present study, we performed a comprehensive genome-wide scan and identified 19 HSP70 superfamily genes in the S. monotuberculatus genome, with the HSP70IV subfamily showing remarkable gene expansion, containing 8 distinct copies. Phylogenetic analysis, conserved motif identification, and gene structure characterization demonstrated high evolutionary conservation within each HSP subfamily. These genes were unevenly distributed across the chromosomes of S. monotuberculatus, and prediction of cis-acting elements revealed that their upstream regulatory regions were enriched with numerous functional elements associated with stress response and immune regulation. Salinity stress experiments revealed that under severe low-salinity conditions (18‰), the expression levels of SmHSPA14L and multiple HSP70IV subfamily members were significantly elevated, while SmHYOU1D was significantly downregulated; in contrast, only subtle changes were detected in the expression of most HSP70 genes under moderate low-salinity stress (24‰). These findings strongly suggest that HSP70 genes, particularly the expanded HSP70IV subfamily, may act as key modulators in the low-salinity stress response. This work provides valuable insight into the molecular mechanisms underlying salinity adaptation in tropical sea cucumbers.

Animals

Cloning of two Hsp70 genes and association analysis between SNP haplotypes and high temperature tolerance trait in red swamp crayfish (Procambarus clarkii).

Aquaculture is suffering the challenge from high temperature climate. Two Hsp70 genes, PcHsp70-1 and PcHsp70-2, as key genes involved in the high temperature tolerance of red swamp crayfish (Procambarus clarkii) were identified and cloned in this study. Their molecular features and expression patterns were characterized, revealing the distinct tissue-specific upregulation expression under high temperature stress (33 °C). Two SNPs, PcHsp70-1 (SNP258) and PcHsp70-2 (SNP555) were examined to associate with high temperature tolerance in three populations (n = 675). The genotypes of PcHsp70-1-SNP258 (GA) and PcHsp70-2-SNP555 (TT) were significantly associated with stronger high temperature tolerance. Notably, individuals carrying the haplotype of Hap I (GG + TT) showed a survival rate exceeding 70% under high temperature stress, whereas, the Hap VIII (AA + CT) showed it at 5.2%. RNA interference of PcHsp70-1 resulted in a significant decrease expression of the gene GSH-Px and its encoding protein (glutathione peroxidase) activity, and damage in intestinal tissue under high temperature stress. The transcriptome result revealed that PcHsp70-1 participates in regulation of the pathways related to cytoskeletal construction, immune response, apoptosis, and antioxidant defense. These findings indicate that PcHsp70 genes are crucial for the cellular stress response under high temperature stress. The developed Kompetitive Allele Specific PCR (KASP) markers provide valuable tools for the marker-assisted selection of high temperature tolerant crayfish varieties, supporting the sustainable development of aquaculture under the challenge of global warming.

Animals

Evolutionary conservation of heat shock proteins in Blattodea and their roles in wing morphogenesis and ovarian development of Blattella germanica.

Heat shock proteins (Hsps) are essential molecular chaperones for protein homeostasis and stress responses. However, the Hsp repertoires and functions in Blattodea remain underexplored. Our genome-scale survey of nine Blattodea species revealed 37-46 conserved Hsp90, Hsp70, and DNAJ (Hsp40) genes, with DNAJ the most abundant and Hsp90 the least. Phylogenetic analysis confirmed the evolutionary conservation of three Hsp90, seven Hsp70, and 29 DNAJ subclades in Blattodea. Selection pressure analysis revealed predominant purifying selection (dN/dS ≪ 1) across lineages, strongest in DNAJ and highest in Hsp90 conservation. In Blattella germanica, expression of six representative BgHsp genes progressively increased during development, peaking in fifth-instar nymphs. Tissue expression profiling revealed that BgHspA1-2/3/4 were predominantly expressed in legs, BgDNAJB5 and BgHsp90AB1-2 were enriched in the fat body, and BgHsp90AB1 was highly expressed in the head. dsRNA injection targeting conserved Hsp gene regions achieved 61.9-94.1% knockdown of all six target genes. RNAi knockdown of six BgHsp genes disrupted wing morphogenesis, causing distinct phenotypes: wing whitening (56.7%, dsBgHspA1-4), unequal length (66.7%, dsBgHspA1-3; 76.7%, dsBgDNAJB5), and wing wrinkling (70%, dsBgHspA1-2; 63.3%, dsBgHsp90AB1; 76.7%, dsBgHsp90AB1-2). During ovarian formation, the developmental delay was most severe in the dsBgHsp90AB1 group, moderate in the dsBgHsp90AB1-2 and dsBgHspA1-2/3/4 groups, and weakest in the dsBgDNAJB5 group. Besides, knockdown significantly downregulated key developmental genes (apterous-a, nubbin, scalloped, ultrabithorax, wingless, and vitellogenin). These findings provide a reference for understanding the evolutionary patterns of Hsps in Blattodea, and offer mechanistic insights into the developmental regulation mediated by Hsps in this important public-health pest.

Animals

Genome-wide characterization of heat shock protein genes reveals thermal stress-responsive candidates in Litopenaeus vannamei.

Heat shock proteins (HSPs) are conserved molecular chaperones involved in protein folding, refolding, aggregation prevention, and degradation of damaged proteins. However, the genomic organization and thermal responsiveness of HSP genes in the Pacific white shrimp (Litopenaeus vannamei) remain incompletely understood. Here, we performed a genome-wide analysis of the HSP gene family and examined its phylogenetic relationships, structural features, duplication patterns, sequence variation, interaction networks, and transcriptional responses to acute heat stress. A total of 34 HSP genes were identified and classified into the HSP90, HSP70, HSP40/DNAJ, HSP60, and small HSP families. Phylogenetic, motif, gene structure, synteny, and subcellular localization analyses revealed evolutionary conservation and structural diversification among family members. Three duplicated gene pairs were identified, comprising two segmental duplications and one tandem duplication. All pairs exhibited Ka/Ks ratios below 1, consistent with purifying selection of varying strength. Sequence analysis identified 295 nonsynonymous single-nucleotide polymorphisms, of which 12 were consistently predicted to be deleterious by multiple algorithms. Protein-protein interaction analysis indicated enrichment of protein-folding and cellular stress-response functions. RT-qPCR analysis showed significant induction of HSPA4, HSP90AA1, TRAP1, BiP, and DNAJA1 after 6, 12, and 24 h of exposure to 34 °C, whereas DNAJC3 was significantly induced only at 12 h. All six genes reached their highest transcript abundance at 12 h. These findings may provide a genomic framework for HSP genes in L. vannamei and identify candidate genes and variants associated with thermal stress responses.

Animals

Transcriptomic insights into thermal stress reveal physiological trade-off between thermal stress adaptation and reproductive investment in Spodoptera litura.

Spodoptera litura, a highly polyphagous lepidopteran pest, poses a major threat to agricultural productivity due to its remarkable adaptability to diverse environmental conditions. Although heat stress is known to trigger transcriptional reprogramming in insects, the molecular mechanisms underlying thermal stress responses in S. litura remain poorly understood. In the present study, fourth-instar larvae were exposed to acute heat stress (44 °C) and compared with control conditions (27 ± 1 °C) to investigate heat-induced transcriptional alterations affecting physiology and reproduction. High-quality RNA-Seq data achieved more than 80% mapping efficiency, with a total of 15,782 transcripts were identified. Transcriptome analysis of S. litura larvae showed 323 differentially expressed genes (DEGs), of which 262 genes were significantly upregulated and 61 were downregulated in heat-stressed larvae compared to the control group. The DEGs were associated with stress response, reproduction, signalling, proteostasis, detoxification, oxidative stress, metabolism, development, and chromatin regulation. Heat shock proteins genes, including HSP70, HSP90, and HSP27, together with co-chaperones such as TRET-1, STIP1, and Starvin, were strongly upregulated, indicating enhanced cellular protection against protein damage and oxidative stress under heat stress. Conversely, key reproductive and cell cycle-related genes, including BARR, CAPD2, FEO, CDK2 and MORULA, were significantly downregulated, suggesting reproductive impairment and developmental arrest. RT-qPCR validation corroborated the RNA-Seq findings, demonstrating a heat-induced physiological trade-off that prioritizes survival over reproduction. Consistent with these molecular responses, heat-stressed insects exhibited marked reproductive impairment, including significant reductions in gonadosomatic index, eupyrene sperm bundle count, mating frequency, mating success, female calling behaviour, copulation duration, fecundity, and egg fertility. Collectively, these findings provide comprehensive insights into the molecular basis of thermal adaptation in S. litura and demonstrate that acute heat stress compromises reproductive fitness while activating conserved stress-response pathways that promote short-term survival.

Animals

Comparative phylogenomics and transcriptional regulatory networks of AQPs, HSPs, and LEA proteins in salt-stressed Portulaca oleracea.

Soil salinization severely threatens global food security, necessitating systematic investigations of halophytes like Portulaca oleracea to decode the molecular mechanisms of environmental resilience. Utilizing an integrated framework of deep learning-based genome annotation (58,817 predicted genes; 96.5% BUSCO completeness), multi-tissue RNA-Seq, phylogenomics, and gene regulatory network (GRN) inference, the synergistic orchestration of 78 aquaporins (AQPs), 525 heat shock proteins (HSPs), and 119 late embryogenesis abundant (LEA) proteins was elucidated. The active transcriptome, encompassing 39,065 expressed loci, revealed a systemic growth-defense trade-off. Tissues displayed distinct adaptive mechanisms: leaves modulated intracellular water balance via specialized AQPs, whereas adult roots maintained proteostasis through robust HSP20/HSP70 induction. Phylogenomic clustering across 154 species demonstrated that salinity tolerance constitutes an evolutionary mosaic, identifying 81 halophyte-exclusive orthogroups and 1129 species-specific clusters. Comparative topology across six independent GRNs (4.2M-5.3 M edges) unmasked a highly modular transcriptional reprogramming strategy governed by a core apparatus of 22 stress-exclusive regulators, with functional enrichment heavily prioritizing protein dimerization and chromatin remodeling. Theoretically, the distinct convergence of Trihelix transcription factors with guard cell differentiation pathways offers a candidate transcriptomic framework to explain the plant's characteristic C4-CAM photosynthetic plasticity under severe osmotic pressure. Practically, these evolutionary blueprints and specific master switches transcend single-gene transgenic limitations. Utilizing these root-sustained and stress-inducible targets under localized promoters provides a naturally optimized, network-level precision engineering roadmap to transfer robust, compartmentalized halotolerance to sensitive glycophytic crops.

Gene Regulatory Networks

Identification of the BrSK gene family in flowering Chinese cabbage and functional characterization of BrSK2 subfamily involvement in heat stress.

Glycogen synthase kinase 3 (GSK3) kinases are evolutionarily conserved regulators of plant development and stress signaling, yet their contributions to thermotolerance in cool-adapted Brassica crops remain poorly understood. Here, we identified 16 BrSK genes in the Caixin (Brassica rapa ssp. chinensis var. parachinensis) genome, all harboring intact catalytic motifs indicative of functional kinase activity. Spatiotemporal expression profiling revealed preferential accumulation of BrSK transcripts in stem apices and floral organs during reproductive transition, while promoter analysis identified abundant heat- and abiotic stress-responsive cis-elements. Under heat stress, BrSK21, BrSK22, and BrSK23 displayed striking genotype-specific expression dynamics. BrSK21/22/23 transcripts were stably suppressed in the heat-tolerant cultivar '49-19' but transiently declined before rapidly rebounding in the heat-sensitive 'Liuye 50', mirroring RNA-seq profiles. Protein-protein interaction assays (Y2H, BiFC, and LCI) demonstrated specific associations between BrSK kinases and BrHSFA1. Functional validation via VIGS revealed that silencing of BrSK21 significantly enhanced thermotolerance, with triple silencing of BrSK21/22/23 conferring additive protection, indicating functional redundancy within the BrSK2 subfamily. Collectively, these findings establish the BrSK2 subfamily as negative regulators of heat tolerance in Caixin, likely via modulation of BrHSFA1 expression. This work identifies high-priority targets for molecular breeding of climate-resilient Brassica vegetables.

Plant Proteins

Integrated physiological and transcriptomic analyses reveal coordinated gill responses to heat stress in pikeperch (Sander lucioperca).

Climate change-driven warming of aquatic environments has made thermal stress an increasingly important factor influencing fish physiological homeostasis. Given their central roles in respiration and osmoregulation, gills are particularly responsive to variations in ambient temperature. Histological examination, physiological measurements, and transcriptome profiling were integrated to investigate the mechanisms associated with heat stress-induced gill injury in pikeperch (Sander lucioperca). Histological analysis revealed that exposure to 29 °C directly caused structural damage to the gills of pikeperch. Oxidative status was evaluated by measuring malondialdehyde (MDA) levels and the activities of antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT). MDA accumulation was significantly enhanced under heat stress, while antioxidant enzyme activities (SOD, POD, and CAT) displayed a transient increase followed by a subsequent decline. Transcriptome profiling showed marked enrichment of the protein processing in endoplasmic reticulum pathway after heat stress, suggesting activation of endoplasmic reticulum (ER) stress in pikeperch gills. With increasing stress duration, the unfolded protein response (UPR) appeared unable to re-establish ER homeostasis, shifting ire1 and atf6 toward a pro-apoptotic state. Protein-protein interaction (PPI) analysis further highlighted hub genes potentially involved in heat stress-induced ER stress and apoptosis. TUNEL staining and western blotting collectively confirmed that heat stress triggered apoptosis in pikeperch gill tissue. Overall, this study provides new insights into the physiological and molecular responses of pikeperch gills to heat stress and enhances our understanding of thermal stress adaptation in cold-water aquaculture species under climate change.

Animals

RPLP0 drives diffuse large B-cell lymphoma cell proliferation through reactive oxygen species-dependent AKT/mTOR activation and inhibition of stress-induced autophagy.

Diffuse large B-cell lymphoma (DLBCL) is a common, aggressive subtype of non-Hodgkin lymphoma with poor outcomes. Identifying the primary molecular causes of DLBCL remains key. The present study examined the function of ribosomal protein lateral stalk subunit P0 (RPLP0) in DLBCL pathogenesis. The Cancer Genome Atlas-DLBCL and GSE12453 datasets overlapping differentially expressed genes were identified. Hub genes were identified via protein-protein interaction network analysis. DLBCL cells were subjected to functional tests following RPLP0 overexpression or knockdown. Reverse transcription-quantitative PCR, western blotting, flow cytometry, transmission electron microscopy, colony formation assay and biochemical analysis were among the tests performed. N-acetylcysteine (NAC), rapamycin (RAPA) and 3-MA were among the medication therapies. In the DLBCL datasets, six ribosome-associated genes were differentially expressed. RPLP0 knockdown inhibited the proliferation of DLBCL cells and caused G2-phase arrest, without impacting apoptosis. Thioredoxin, heat shock protein family A member 1A and heat shock protein family B member 1 expression was downregulated by RPLP0 knockdown, which also increased the NAD+/NADH ratio, promoted reactive oxygen species (ROS) accumulation and caused mitochondrial membrane potential depolarization. Meanwhile, 3-MA reversed the effects of RPLP0 knockdown, which encouraged LC3-II accumulation, autophagy-related gene 5 (ATG5) overexpression and an increase in autophagic vesicles. Autophagy-related indicators were decreased, and AKT/mTOR phosphorylation was increased by RPLP0 overexpression, which RAPA inhibited. NAC therapy preserved the viability of RPLP0-silenced cells, restored p-AKT/p-mTOR levels and restored normal LC3 and ATG5 expression. These findings suggest that RPLP0 regulates stress-induced autophagy through ROS-dependent AKT/mTOR signaling and may represent a potential therapeutic target for DLBCL.

AKT/mTOR signaling pathway

Proteomic responses of the oil palm pest Metisa plana (Psychidae) to farnesyl acetate exposure.

Metisa plana Walker (Lepidoptera: Psychidae) is a major defoliator of oil palm in Malaysia, causing substantial economic losses. Farnesyl acetate (FA), a sesquiterpenoid compound, has been proposed as a potential insecticidal agent against M. plana, yet its molecular impact on larval physiology remains poorly understood. Here, we employed label-free quantitative proteomics, functional enrichment analysis, and targeted transcript assessment to characterize the temporal proteomic response of M. plana larvae at 7 and 14 days after treatment (DAT) with FA. Principal component analysis revealed robust separation between treated and control samples at both time points, indicating sustained treatment-driven proteomic restructuring. Early exposure (7 DAT) elicited a heterogeneous response involving stress-associated proteins, redox enzymes, and cytoskeletal regulators, whereas later exposure (14 DAT) produced a consolidated profile characterized by metabolic reprogramming, downregulation of ribosomal proteins, induction of heat shock proteins, and enrichment of RNA surveillance and mitochondrial pathways. Targeted transcript analysis qualitatively supported proteomic trends for HSP83 and aldehyde dehydrogenase X, although limited amplification precluded quantitative inference. Collectively, these findings demonstrate that FA exposure drives a shift from acute proteomic perturbation toward a maintenance-oriented physiological state, prioritizing proteostasis, energy management, and stress adaptation over growth and development. This integrated molecular perspective provides mechanistic insight into the chronic effects of FA, highlighting its potential to suppress larval performance and informing the development of biorational, physiology-based pest management strategies in non-model insects.

Animals

A chromosomal gtrB homolog and dam differentially contribute to dry-heat and high hydrostatic pressure resistance in Salmonella enterica.

Salmonella enterica can persist in low-moisture foods and shows enhanced dry-heat resistance under low water activity, posing significant food safety challenges. However, the genetic basis of extreme dry-heat resistance and its relationship with other processing stresses remain unclear. In this study, twelve S. enterica strains were screened for dry-heat treatment at 60 °C and 80 °C, with S. Infantis CICC21649 identified as the most resistant strain. Comparative genomics and transcriptional analysis identified candidate genes related to envelope integrity and regulation, including gtrB and dam. Deletion of the chromosomal gtrB homolog reduced dry-heat resistance, producing an additional 0.91-log10 reduction relative to the parent strain at 80 °C. Deletion of dam caused broader stress sensitivity, reducing resistance to both dry heat and high hydrostatic pressure, with the stronger phenotype observed under high hydrostatic pressure. Proteomic analysis of the chromosomal gtrB homolog mutant revealed broad alterations in envelope-associated proteins, transport functions, oxidative stress pathways, and central metabolism under dry-heat stress. These findings indicate that the chromosomal gtrB homolog is an important contributor to extreme dry-heat resistance, whereas dam contributes to resistance against both dry-heat and high hydrostatic pressure, likely through a broader regulatory role in stress adaptation. These results reveal distinct structural and regulatory layers underlying stress adaptation in S. enterica and provide practical guidance for low-moisture food processing by highlighting the need to account for strain-dependent and stress-specific resistance during process validation.

Hydrostatic Pressure

Long-term heat exposure reshapes muscle molecular regulation and enhances thermal tolerance in Clarias fuscus.

Rapid fluctuations in water temperature driven by global warming have become a major abiotic stressor affecting muscle function in teleost fish. This study examined the effects of long-term thermal conditions on heat tolerance in Clarias fuscus. Fish were maintained for 90 days at either a normal temperature group (NT, 26 °C) or a high-temperature group (HT, 34 °C). Subsequently, muscle histology, and transcriptomic profiles were observed following acute high-temperature exposure (34 °C) and after temperature recovery (26 °C). Histological analysis showed that fish from the NT under acute high-temperature stress exhibited severe muscle damage (atrophy, myofilament disruption, and myolysis), whereas fish from the HT displayed markedly reduced lesions. RNA-seq profiling revealed 5769 differentially expressed genes (DEGs) in the NT and 3292 DEGs in the HT following acute temperature challenges. Functional enrichment indicated that, in the HT, modulation of key cell cycle regulators (e.g., ccna, ccnb, cdk1, cdk2) contributed to alleviating muscle damage caused by temperature fluctuations. In the NT, genes associated with ribosome biogenesis (e.g., nop56, riok2, riok1) were up-regulated and then down-regulated during temperature fluctuation, whereas p53 in the cell cycle pathway showed the opposite expression pattern. These findings demonstrate long-term heat exposure reshapes molecular expression and regulatory mechanisms in the muscle of C. fuscus, thereby enhancing thermal tolerance and adaptability, and providing a theoretical basis for breeding heat-resistant, high-quality aquaculture strains.

Animals

Epitranscriptomic erasers in bivalves: Evolutionary divergence and species-specific transcriptional plasticity of the ALKBH family under acute thermal stress.

The AlkB homolog (ALKBH) family of Fe(II)/α-ketoglutarate-dependent dioxygenases mediates nucleic acid demethylation, thereby governing RNA metabolism and genomic stability. Despite their pivotal roles in epitranscriptomic regulation across vertebrates, the evolutionary dynamics and functional significance of ALKBH proteins in bivalve mollusks remain largely unexplored. Here, we present a comprehensive phylogenomic analysis of 210 ALKBH genes identified across 35 bivalve species. Our analyses reveal a distinct evolutionary trajectory characterized by the lineage-specific loss of ALKBH4 and the restricted distribution of ALKBH5 to the Mytilidae family, contrasting sharply with vertebrate repertoires. Using the noble scallop (Chlamys nobilis) and Pacific oyster (Crassostrea gigas) as model systems, we demonstrate that ALKBH genes exhibit conserved spatiotemporal expression patterns, with pronounced enrichment in gonadal tissues and during metamorphic transitions, implicating these enzymes in gametogenesis and larval development. Furthermore, comparative thermal stress experiments reveal divergent transcriptional plasticity: the subtropical scallop C. nobilis mounts rapid, transient induction of ALKBH1/2/6 under heat shock, whereas the eurythermal oyster C. gigas maintains sustained ALKBH3 expression, potentially underpinning its superior thermal tolerance. Conversely, cold stress elicits bimodal regulation in C. nobilis, with ALKBH1/2 upregulation contrasting with ALKBH6/7/8 suppression. These findings illuminate the functional diversification of bivalve ALKBH genes and their potential utility as molecular biomarkers for assessing developmental competence and thermal resilience in shellfish aquaculture.

Animals

Spermidine and melatonin ameliorate heat stress-induced decline in sheep semen quality.

Heat stress impairs reproductive performance in sheep through endocrine disruption and oxidative stress. This study evaluated the protective effects of spermidine (SPD) and melatonin (MT) supplementation on semen quality in Dorper rams during summer. Twenty-four rams were randomly assigned to a control group, an SPD group (5&#x202f;mg/kg, dietary supplementation), or an MT group (60&#x202f;mg, subcutaneous implantation) and treated for 60 days. The temperature-humidity index (THI) was monitored throughout the experimental period. Compared with the control group, MT significantly reduced serum cortisol concentration on day 30 (P&#x202f;<&#x202f;0.05), whereas no significant differences were observed at the other sampling time points. Serum testosterone, spermidine, and melatonin concentrations remained unchanged throughout the study (P&#x202f;>&#x202f;0.05). SPD supplementation significantly increased ejaculate volume on day 35 and sperm motility on day 42 (P&#x202f;<&#x202f;0.05), whereas MT did not significantly affect these parameters. Neither treatment reduced the overall sperm abnormality rate. However, both SPD and MT significantly decreased the proportion of acephalic and decaudated sperm on day 56 (P&#x202f;<&#x202f;0.05). Neither treatment significantly affected pregnancy rate, delivery rate, or the expression of PMFBP1 and SUN5 proteins in semen (P&#x202f;>&#x202f;0.05). Regarding oxidative stress, MT significantly downregulated CAT protein expression (P&#x202f;<&#x202f;0.05), whereas SPD significantly reduced MDA content and SOD1 protein expression (P&#x202f;<&#x202f;0.05); MT showed similar but non-significant trends for these two markers (P&#x202f;>&#x202f;0.05). Collectively, these findings demonstrate that SPD and MT exert distinct protective effects against heat stress, with SPD improving selected semen quality traits and both treatments reducing sperm head-tail separation, although these benefits did not translate into improved reproductive performance.

Animals

Diurnal differences in the effects of heat exposure on renal function: A randomized controlled crossover trial.

High temperature is a major risk factor for kidney injury, and population exposure to nighttime heat is increasing as the climate warms. However, whether renal responses to heat exposure differ between daytime and nighttime remains unclear. Forty-one healthy adults participated in a randomized crossover experiment conducted in a controlled laboratory setting. Participants were exposed to heat (32&#xb0;C during daytime; 30&#xb0;C during nighttime) and thermoneutral conditions (26&#xb0;C) for 8&#x202f;h. Blood and urine samples were collected before and after each exposure to examine various renal biomarkers reflecting glomerular filtration function, tubular injury, and early kidney stress. Heat exposure affected both blood and urinary biomarkers of kidney function, with notable diurnal differences in renal responses. Daytime heat exposure primarily affected blood markers of glomerular filtration, increasing creatinine by 7.67% (95% CI: 4.73%-10.61%) and cystatin C by 3.05% (95% CI: 0.17%-5.93%), while reducing estimated glomerular filtration rate by 0.05% (95% CI: 0.02%-0.08%). In contrast, nighttime heat exposure predominantly elevated urinary biomarkers of early kidney stress, including insulin-like growth factor-binding protein 7 (58.40%, 95% CI: 27.66%-89.14%), kidney injury molecule-1 (47.25%, 95% CI: 18.91%-75.59%), and tissue inhibitor of metalloproteinases-2 (51.88%, 95% CI: 22.26%-81.51%). Moreover, increases in insulin-like growth factor-binding protein 7 were significantly greater at night than during the day. Sleep-related parameters, including sleep quality, duration, and heart rate variability, partially mediated nighttime heat effects on renal responses. These results indicated that heat exposure induced different diurnal patterns in renal responses.

Humans

The effects of cold temperature on the development, microbiome, and transcriptome of the sea anemone Nematostella vectensis.

Thermal conditions impact essentially all aspects of the physiology for ectotherms. While the effects of high temperatures have been widely studied, cold temperature effects on aquatic invertebrates and their microbial communities have been poorly characterized. To determine the diverse effects of exposure to cold temperatures, we assessed acute and long-term impacts of ecologically relevant low temperatures on the development, microbiome, and gene expression of the sea anemone Nematostella vectensis. Two hours post fertilization, embryos were exposed to temperatures from 4&#xb0;C to 35&#xb0;C and development rate to the juvenile stage was quantified. We found temperature impacts the development rate of embryos, where lower temperatures extended development time and resulted in mortality below 10&#xb0;C. For both microbiome and host transcriptomic responses, anemones were held at 20&#xb0;C, 10&#xb0;C, and 0&#xb0;C and compared at 24 hours and 7 days. Extended exposures to colder temperatures caused restructuring of the host-associated microbiome, with the loss of common taxonomic groups from the class Bacteroidia and Bacilli. Lastly, cold stress induced significant changes in gene expression, which were more pronounced at the 10&#xb0;C than 0&#xb0;C but showed little change over time in each temperature. Interestingly, expression of genes associated with innate immunity were among the most differentially expressed genes including heat shock proteins and innate immune genes providing a potential host-imposed mechanism to explain the shift in the microbiome. Overall, cold temperatures have broad effects on many facets of this sea anemone and its microbial community and indicate the importance of cold temperature events when characterizing how ectotherms acclimate to thermal variation.

Animals

Fyn signaling in the medial prefrontal cortex regulates resistance to stress-induced object recognition impairments in male rats.

Genome-wide association studies on patients with depression have identified FYN and FYB, an FYN-binding protein, as being linked to depression. We have reported that experimental manipulations in gene expression in the medial prefrontal cortex (mPFC) alter stress-induced object recognition impairments in animals. Therefore, we examined the impact of alterations in FYN and FYB expression in the mPFC of adult male rats on resistance to stress-induced impairments in object recognition. Animals with virus-mediated knockdown or overexpression of Fyn in the mPFC were subjected to either a brief 20-min restraint with 20 intermittent tail shocks, which does not induce object recognition impairment, or a prolonged 60-min restraint with 60 intermittent tail shocks, which does. In an object recognition task, control rats maintained intact object recognition following a brief stress, whereas rats with Fyn knockdown or overexpression in the mPFC showed impaired object recognition. Prolonged stress impaired object recognition in both control rats and rats with Fyn knockdown or overexpression. Additionally, rats with Fyn knockdown in the mPFC exhibited fewer c-Fos-positive cells in the mPFC in response to brief stress, accompanied by a trend toward increased c-Fos in the amygdala compared with control rats. Fyn knockdown also reduced Fyb expression in the mPFC. Furthermore, Fyb knockdown in the mPFC impaired object recognition following brief stress, suggesting that the observed effects are consistent with involvement of a coupled Fyn-Fyb signaling axis rather than Fyn alone. These findings suggest that altered Fyn-related signaling in the mPFC may underlie the resistance to stress-induced object recognition impairments.

Animals