Heat-shock proteins, molecular chaperones, and the stress response: evolutionary and ecological physiology

Physiological and transcriptomic analysis provides new insights into osmoregulation mechanism of Ruditapes philippinarum under low and high salinity stress

The Manila clam (Ruditapes philippinarum) is a commercially important marine bivalve, which inhabits the estuarine and mudflat areas. The osmoregulation is of great significance for molluscs adaptation to salinity fluctuations. In this study, we investigated the effects of low salinity (10 psu) and high salinity (40 psu) stress on survival and osmoregulation of the R. philippinarum. The results of physiological parameters showed that the ion (Na+, K+, Cl-) concentrations and Na+/K+-ATPase (NKA) activity of R. philippinarum decreased significantly under low salinity stress, but increased significantly under high salinity stress, indicating that there are differences in physiological adaptation of osmoregulation of R. philippinarum. In addition, we conducted the transcriptome analysis in the gills of R. philippinarum exposed to low (10 psu) and high (40 psu) salinity challenge for 48 h using RNA-seq technology. A total of 153 and 640 differentially expressed genes (DEGs) were identified in the low salinity (LS) group and high salinity (HS) group, respectively. The immune (IAP, TLR6, C1QL4, Ank3), ion transport (Slc34a2, SLC39A14), energy metabolism (PCK1, LDLRA, ACOX1) and DNA damage repair-related genes (Gadd45g, HSP70B2, GATA4) as well as FoxO, protein processing in endoplasmic reticulum and endocytosis pathways were involved in osmoregulation under low salinity stress of R. philippinarum. Conversely, the ion transport (SLC6A7, SLC6A9, SLC6A14, TRPM2), amino acid metabolism (GS, TauD, ABAT, ALDH4A1) and immune-related genes (MAP2K6, BIRC7A, CTSK, GVIN1), and amino acid metabolism pathways (beta-Alanine, Alanine, aspartate and glutamate, Glutathione) were involved in the process of osmoregulation under high salinity stress. The results obtained here revealed the difference of osmoregulation mechanism of R. philippinarum under low and high salinity stress through physiological and molecular levels. This study contributes to the assessment of salinity adaptation of bivalves in the context of climate change and provides useful information for marine resource conservation and aquaculture.

EGCG alleviates heat-stress-induced fat deposition by targeting HSP70 through activation of AMPK-SIRT1-PGC-1α in porcine subcutaneous preadipocytes

Obesity has emerged as a prominent global health concern, with heat stress posing a significant challenge to both human health and animal well-being. Despite a growing interest in environmental determinants of obesity, very few studies have examined the associations between heat stress-related environmental factors and adiposity. Consequently, there exists a clear need to understand the molecular mechanisms underlying the obesogenic effects of heat stress and to formulate preventive strategies. This study focused on culturing porcine subcutaneous preadipocytes at 41.5 ℃ to induce heat stress, revealing that this stressor triggered apoptosis and fat deposition. Analysis demonstrated an upregulation in the expression of HSP70, BAX, adipogenesis-related genes (PPARγ, AP2, CEBPα and FAS), the p-AMPK/AMPK ratio and SIRT1, PGC-1α in the heat stress group compared to the control group (P < 0.05). Conversely, the expression of lipid lysis-related genes (ATGL, HSL and LPL) and Bcl-2 decreased in the heat stress group compared to the control group (P < 0.05). Furthermore, subsequent activator and/or inhibitor experiments validated that heat stress modulated HSP70 and AMPK signalling pathways to enhance lipogenesis and inhibit lipolysis in porcine subcutaneous preadipocytes. Importantly, this study reveals, for the first time, that EGCG mitigates heat-stress-induced fat deposition by targeting HSP70 through the activation of AMPK-SIRT1-PGC-1α in porcine subcutaneous preadipocytes. These findings elucidate the molecular mechanisms contributing to heat stress-induced obesity and provide a foundation for the potential clinical utilisation of EGCG as a preventive measure against both heat stress and obesity.

Transcriptome response of a marine copepod in response to environmentally-relevant concentrations of saxitoxin

Paralytic shellfish toxins (PSTs) can pose a serious threat to human health. Among them, saxitoxin (STX) is one of the most potent natural neurotoxins. Here, the copepod Tigriopus japonicus, was exposed to environmentally relevant concentrations (2.5 and 25 μg/L) STX for 48 h. Although no lethal effects were observed at both concentrations, the transcriptome was significantly altered, and displayed a concentration-dependent response. STX exposure decreased the copepod's metabolism and compromised immune defense and detoxification. Additionally, STX disturbed signal transduction, which might affect other cellular processes. STX exposure could inhibit the copepod's chitin metabolism, disrupting its molting process. Also, the processes related to damage repair and protection were up-regulated to fight against high concentration exposure. Collectively, this study has provided an early warning of PSTs for coastal ecosystem not only because of their potent toxicity effect but also their bioaccumulation that can transfer up the food chain after ingestion by copepods.

Xenohormetic Phytochemicals Inhibit Neovascularization in Microphysiological Models of Vasculogenesis and Tumor Angiogenesis

Xenohormesis proposes that phytochemicals produced to combat stressors in the host plant exert biochemical effects in animal cells lacking cognate receptors. Xenohormetic phytochemicals such as flavonoids and phytoalexins modulate a range of human cell signaling mechanisms but functional correlations with human pathophysiology are lacking. Here, potent inhibitory effects of grapefruit-derived Naringenin (Nar) and soybean-derived Glyceollins (Gly) in human microphysiological models of bulk tissue vasculogenesis and tumor angiogenesis are reported. Despite this interference of vascular morphogenesis, Nar and Gly are not cytotoxic to endothelial cells and do not prevent cell cycle entry. The anti-vasculogenic effects of Glyceollin are significantly more potent in sex-matched female (XX) models. Nar and Gly do not decrease viability or expression of proangiogenic genes in triple negative breast cancer (TNBC) cell spheroids, suggesting that inhibition of sprouting angiogenesis by Nar and Gly in a MPS model of the (TNBC) microenvironment are mediated via direct effects in endothelial cells. The study supports further research of Naringenin and Glyceollin as health-promoting agents with special attention to mechanisms of action in vascular endothelial cells and the role of biological sex, which can improve the understanding of dietary nutrition and the pharmacology of phytochemical preparations.

Surviving in a multistressor world: Gene expression changes in earthworms exposed to heat, desiccation, and chemicals

An investigation of the effects of anthropogenic stress on terrestrial ecosystems is urgently needed. In this work, we explored how exposure to heat, desiccation, and chemical stress alters the expression of genes that encode heat shock proteins (HSPs), an enzyme that responds to oxidative stress (CAT), hypoxia-related proteins (HIF1 and HYOU), and a DNA repair-related protein (PARP1) in the earthworm Eisenia fetida. Exposure to heat (31°C) for 24 h upregulated HSPs and hypoxia-related genes, suggesting possible acquired thermotolerance. Desiccation showed a similar expression profile; however, the HSP response was activated to a lesser extent. Heat and desiccation activated the small HSP at 24 h, suggesting that they may play a role in adaptation. Simultaneous exposure to endosulfan and temperature for 7 h upregulated all of the evaluated genes, implicating a coordinated response involving multiple biological processes to ensure survival and acclimation. These results highlight the relevance of multistress analysis in terrestrial invertebrates.

Effects of adding Bacillus subtilis natto NTU-18 in paste feed on growth, intestinal morphology, gastrointestinal microbiota diversity, immunity, and disease resistance of Anguilla japonica glass eels

Japanese eel, Anguilla japonica, holds significant importance in Taiwanese aquaculture. With the intensification of eel farming, the impact of Edwardsiella tarda has become increasingly severe. Consequently, the abusive use of antibiotics has risen. Bacillus subtilis natto NTU-18, a strain of Bacillus with a high survival rate in feed processing, plays a crucial role in promoting intestinal health through competitive rejection, enhancing immune responses against bacterial pathogens, and improving intestinal health by modulating gastrointestinal microbiota to produce beneficial metabolites of mice and grass carp, Ctenopharyngodon idella. This study investigated the effects of different proportions (control, 0.25 %, 0.5 %, 1 %, and 2 %) of B. subtilis natto NTU-18 added to paste feed on the growth performance, intestinal morphology, and microbiota, expression of immune-related genes, and resistance to E. tarda in Japanese glass eel. The results indicated that the growth performance of all groups with B. subtilis natto NTU-18 added was significantly higher than that of the control group and did not impact the villi morphology. The expression of immune-related genes in the kidney, specifically HSP70 and SOD, was significantly higher from 0.5 % and above than the control; however, no significant differences were observed in CAT, POD, and HSP90. In the liver, significant differences were found in HSP70 and IgM above 0.25 % compared to the control group, with no significant differences in SOD, CAT, POD, and HSP90 among all groups. Additionally, intestinal microbiota analysis revealed that the 2 % additional group had significantly lower diversity than other groups, with Cetobacterium as the dominant species. The challenge test observed that the survival rates of the 0.5 % and 1 % groups were significantly higher. This research suggests that adding 0.5 % and 1 % of B. subtilis natto NTU-18 to the diet is beneficial for Japanese glass eel's immunity, growth performance, and disease resistance.

Phosphorylation of 399S at CsHsp70 of Cymbidium sinense is essential to maintain chlorophyll stability

The Chinese orchids symbolise nobility and gentility in China, and the variation of leaf color makes Cymbidium sinense more diversified and valuable. However, its color variations especially at the protein level still remain largely unexplored. In this study, the proteomics and phosphoproteomics of Cymbidium sinense leaf color variation mutants were studied. A total of 1059 differentially abundant proteins (DAPs) and 1127 differentially abundant phosphorylation sites belonging to 644 phosphoproteins (DAPPs) were identified in the yellow section of leaf variegation mutant of Cymbidium sinense (MY) compared with the green section (MG). Moreover, 349 co-expressing proteins were found in both omics' datasets, while only 26 proteins showed the same expression patterns in the two omics. The interaction network analysis of kinases and phosphatases showed that DAPs and DAPPs in photosynthesis, response to hormones, pigment metabolic process, phosphorylation, glucose metabolic process, and dephosphorylation might contribute to leaf color variation. The abundance of 28 Hsps and 28 phosphorylation sites belonging to 10 Hsps showed significant differences between MG and MY. CsHsp70 was selected to explore the function in Cymbidium sinense leaf variegation. The results showed CsHsp70 is essential for maintaining photosynthetic pigment content and the 399S phosphorylation site is crucial to the function of CsHsp70. Collectively, our findings construct a comprehensive coverage of protein and protein phosphorylation in leaf variegation of C. sinense, providing valuable insights into its formation mechanisms.

HSP70A promotes the photosynthetic activity of marine diatom Phaeodactylum tricornutum under high temperature

With global climate change, the high-temperature environment has severely impacted the community structure and phenotype of marine diatoms. Phaeodactylum tricornutum, a model species of marine diatom, is sensitive to high temperature, which grow slowly under high temperature. However, the regulatory mechanism of P. tricornutum in response to high-temperature is still unclear. In this study, we found that the expression level of the HSP70A in the wild type (WT) increased 28 times when exposed to high temperature (26°C) for 1 h, indicating that HSP70A plays a role in high temperature in P. tricornutum. Furthermore, overexpression and interference of HSP70A have great impact on the exponential growth phase of P. tricornutum under 26°C. Moreover, the results of Co-immunoprecipitation (Co-IP) suggested that HSP70A potentially involved in the correct folding of the photosynthetic system-related proteins (D1/D2), preventing aggregation. The photosynthetic activity results demonstrated that overexpression of HSP70A improves non-photochemical quenching (NPQ) activity under high-temperature stress. These results reveal that HSP70A regulates the photosynthetic activity of P. tricornutum under high temperatures. This study not only helps us to understand the photosynthetic activity of marine diatoms to high temperature but also provides a molecular mechanism for HSP70A in P. tricornutum under high-temperature stress.

Thermal tolerance of a freshwater amphipod Gammarus lacustris can be enhanced by acclimation to higher mineralization

Temperature and mineralization are among the most important environmental factors affecting all processes of aquatic ecosystems, including geographical distribution of water animals. Previously we showed that a brackish water population of Gammarus lacustris, a widespread amphipod, demonstrates substantially higher thermotolerance than a freshwater population. A possible reason for this difference is the fact that brackish water conditions are closer to internal media mineralization. Here we aimed to test this hypothesis and relate the observed effects in animal survival under the heat shock to the status of cellular defence systems. We acclimated four groups of amphipods from the same freshwater population to 0.5 ‰ and 15 ‰ at the temperatures of 6°С or 15°С. Acclimation at 6°С, but not at 15°С, to 15 ‰ significantly increased resistance of the amphipods to heat shock at 30°C. At 6°С activities of antioxidant enzymes and levels of the lipid peroxidation products in G. lacustris did not react to the increase in mineralization and the heat shock, while the level of HSP70 elevated two-fold in amphipods acclimated to mineralization of 15 ‰ compared to animals acclimated to 0.5 ‰. Thus, the observed increase in thermotolerance could be explained by the higher initial level of HSP70 and potentially other heat shock proteins caused by a less energy-demanding, more isotonic level.

Biochemical and molecular biomarkers and their association with anthropogenic chemicals in wintering Manx shearwaters (Puffinus puffinus)

Anthropogenic pollution poses a threat to marine conservation by causing chronic toxic effects. Seabirds have contact throughout their lives with pollutants like plastic, metals, polychlorinated biphenyls (PCBs), and organochlorine pesticides such as hexachlorocyclohexanes (HCHs). We assessed 155 Manx shearwaters (Puffinus puffinus) stranded along the Brazilian coast, analyzing associations between organic pollutants, plastic ingestion, biomarkers (transcript levels of aryl hydrocarbon receptor, cytochrome P450-1A-5 [CYP1A5], UDP-glucuronosyl-transferase [UGT1], estrogen receptor alpha-1 [ESR1], and heat shock protein-70 genes) and enzymes activity (ethoxy-resorufin O-deethylase and glutathione S-transferase [GST]). Plastic debris was found in 29 % of the birds. The transcription of UGT1 and CYP1A5 was significantly associated with hexachlorobenzene (HCB) and PCBs levels. ESR1 was associated with HCB and Mirex, and GST was associated with Drins and Mirex. While organic pollutants affected shearwaters more than plastic ingestion, reducing plastic availability remains relevant as xenobiotics are also potentially adsorbed onto plastics.

Body color plasticity of Diaphorina citri reflects a response to environmental stress

Body color polyphenism is common in Diaphorina citri. Previous studies compared physiological characteristics in D. citri, but the ecological and biological significance of its body color polyphenism remains poorly understood. We studied the ecological and molecular effects of stressors related to body color in D. citri. Crowding or low temperature induced a high proportion of gray morphs, which had smaller bodies, lower body weight, and greater susceptibility to the insecticide dinotefuran. We performed transcriptomic and metabolomics analysiis of 2 color morphs in D. citri. Gene expression dynamics revealed that the differentially expressed genes were predominantly involved in energy metabolism, including fatty acid metabolism, amino acid metabolism, and carbohydrate metabolism. Among these genes, plexin, glycosidase, phospholipase, take out, trypsin, and triacylglycerol lipase were differentially expressed in 2 color morphs, and 6 hsps (3 hsp70, hsp83, hsp90, hsp68) were upregulated in gray morphs. The metabolome data showed that blue morphs exhibited a higher abundance of fatty acid and amino acid, whereas the content of carbohydrates was elevated in gray morphs. This study partly explains the body color polyphenism of D. citri and provides insights into the molecular changes of stress response of D. citri.

pH Dependence of HSF1 trimerization is shaped by intramolecular interactions

Heat shock factor 1 (HSF1) primarily regulates various cellular stress responses. Previous studies have shown that low pH within the physiological range directly activates HSF1 function in vitro. However, the detailed molecular mechanisms remain unclear. This study proposes a molecular mechanism based on the trimerization behavior of HSF1 at different pH values. Extensive mutagenesis of human and goldfish HSF1 revealed that the optimal pH for trimerization depended on the identity of residue 103. In particular, when residue 103 was occupied by tyrosine, a significant increase in the optimal pH was observed, regardless of the rest of the sequence. This behavior can be explained by the protonation state of the neighboring histidine residues, His101 and His110. Residue 103 plays a key role in trimerization by forming disulfide or non-covalent bonds with Cys36. If tyrosine resides at residue 103 in an acidic environment, its electrostatic interactions with positively charged histidine residues prevent effective trimerization. His101 and His110 are neutralized at a higher pH, which releases Tyr103 to interact with Cys36 and drives the effective trimerization of HSF1. This study showed that the protonation state of a histidine residue can regulate the intramolecular interactions, which consequently leads to a drastic change in the oligomerization behavior of the entire protein.

Intermolecular Interactions between Cysteine and Aromatic Amino Acids with a Phenyl Moiety in the DNA-Binding Domain of Heat Shock Factor 1 Regulate Thermal Stress-Induced Trimerization

In this study, we investigated the trimerization mechanism and structure of heat shock factor 1 (HSF1) using western blotting, tryptophan (Trp) fluorescence spectroscopy, and molecular modeling. First, we examined the DNA-binding domains of human (Homo sapiens), goldfish (Carassius auratus), and walleye pollock (Gadus chalcogrammus) HSF1s by mutating key residues (36 and 103) that are thought to directly affect trimer formation. Human, goldfish, and walleye pollock HSF1s contain cysteine at residue 36 but cysteine (C), tyrosine (Y), and phenylalanine (F), respectively, at residue 103. The optimal trimerization temperatures for the wild-type HSF1s of each species were found to be 42, 37, and 20 °C, respectively. Interestingly, a mutation experiment revealed that trimerization occurred at 42 °C when residue 103 was cysteine, at 37 °C when it was tyrosine, and at 20 °C when it was phenylalanine, regardless of the species. In addition, it was confirmed that when residue 103 of the three species was mutated to alanine, trimerization did not occur. This suggests that in addition to trimerization via disulfide bond formation between the cysteine residues in human HSF1, trimerization can also occur via the formation of a different type of bond between cysteine and aromatic ring residues such as tyrosine and phenylalanine. We also confirmed that at least one cysteine is required for the trimerization of HSF1s, regardless of its position (residue 36 or 103). Additionally, it was shown that the trimer formation temperature is related to growth and survival in fish.

Genome-wide identification, classification and expression analysis of the heat shock transcription factor family in Garlic (Allium sativum L.)

BACKGROUND

The heat shock transcription factor (HSF) plays a crucial role in the regulatory network by coordinating responses to heat stress as well as other stress signaling pathways. Despite extensive studies on HSF functions in various plant species, our understanding of this gene family in garlic, an important crop with nutritional and medicinal value, remains limited. In this study, we conducted a comprehensive investigation of the entire garlic genome to elucidate the characteristics of the AsHSF gene family.

RESULTS

In this study, we identified a total of 17 AsHSF transcription factors. Phylogenetic analysis classified these transcription factors into three subfamilies: Class A (9 members), Class B (6 members), and Class C (2 members). Each subfamily was characterized by shared gene structures and conserved motifs. The evolutionary features of the AsHSF genes were investigated through a comprehensive analysis of chromosome location, conserved protein motifs, and gene duplication events. These findings suggested that the evolution of AsHSF genes is likely driven by both tandem and segmental duplication events. Moreover, the nucleotide diversity of the AsHSF genes decreased by only 0.0002% from wild garlic to local garlic, indicating a slight genetic bottleneck experienced by this gene family during domestication. Furthermore, the analysis of cis-acting elements in the promoters of AsHSF genes indicated their crucial roles in plant growth, development, and stress responses. qRT-PCR analysis, co-expression analysis, and protein interaction prediction collectively highlighted the significance of Asa6G04911. Subsequent experimental investigations using yeast two-hybridization and yeast induction experiments confirmed its interaction with HSP70/90, reinforcing its significance in heat stress.

CONCLUSIONS

This study is the first to unravel and analyze the AsHSF genes in garlic, thereby opening up new avenues for understanding their functions. The insights gained from this research provide a valuable resource for future investigations, particularly in the functional analysis of AsHSF genes.

Critical thermal maxima and oxygen uptake in Elysia viridis, a sea slug that steals chloroplasts to photosynthesize

Photosynthetic animals produce oxygen, providing an ideal lens for studying how oxygen dynamics influence thermal sensitivity. The algivorous sea slug Elysia viridis can steal and retain chloroplasts from the marine alga Bryopsis sp. for months when starved, but chloroplast retention is mere weeks when they are fed another green alga, Chaetomorpha sp. To examine plasticity in thermal tolerance and changes in net oxygen exchange when fed and starving, slugs fed each alga were acclimated to 17°C (the current maximum temperature to which they are exposed in nature) and 22°C (the increase predicted for 2100) and measured at different points during starvation. We also examined increased illumination to evaluate a potential tradeoff between increased oxygen production but faster chloroplast degradation. Following acclimation, we subjected slugs to acute thermal stress to determine their thermal tolerance. We also measured net oxygen exchange before and after acute thermal stress. Thermal tolerance improved in slugs acclimated to 22°C, indicating they can acclimate to temperatures higher than they naturally experience. All slugs exhibited net oxygen uptake, and rates were highest in recently fed slugs before exposure to acute thermal stress. Oxygen uptake was suppressed following acute thermal stress. Under brighter light, slugs exhibited improved thermal tolerance, possibly because photosynthetic oxygen production alleviated oxygen limitation. Accordingly, this advantage disappeared later in starvation when photosynthesis ceased. Thus, E. viridis can cope with heatwaves by suppressing metabolism and plastically adjusting heat tolerance; however, starvation influences a slug's thermal tolerance and oxygen uptake such that continuous access to algal food for its potential nutritive and oxygenic benefits is critical when facing thermal stress.

Multigenerational Effect of Heat Stress on the Drosophila melanogaster Sperm Proteome

The effect of the parental environment on offspring through non-DNA sequence-based mechanisms, such as DNA methylation, chromatin modifications, noncoding RNAs, and proteins, could only be established after the conception of "epigenetics". These effects are now broadly referred to as multigenerational epigenetic effects. Despite accumulating evidence of male gamete-mediated multigenerational epigenetic inheritance, little is known about the factors that underlie heat stress-induced multigenerational epigenetic inheritance via the male germline in Drosophila. In this study, we address this gap by utilizing an established heat stress paradigm in Drosophila and investigating its multigenerational effect on the sperm proteome. Our findings indicate that multigenerational heat stress during the early embryonic stage significantly influences proteins in the sperm associated with translation, chromatin organization, microtubule-based processes, and the generation of metabolites and energy. Assessment of life-history traits revealed that reproductive fitness and stress tolerance remained unaffected by multigenerational heat stress. Our study offers initial insights into the chromatin-based epigenetic mechanisms as a plausible means of transmitting heat stress memory through the male germline in Drosophila. Furthermore, it sheds light on the repercussions of early embryonic heat stress on male reproductive potential. The data sets from this study are available at the ProteomeXchange Consortium under the identifier PXD037488.

Screening and Identification of the Biomarkers Applied for the Evaluation of Acute and Chronic Thermal Tolerance Ability in Largemouth Bass (Micropterus salmoides)

Affected by the continuously rising temperature, thermal stress leads to a delinked growth rate and resistance to stress in cultured largemouth bass (Micropterus salmoides, LMB) in China. Identification of LMB with better thermal resistance will benefit the breeding of new varieties. However, there has been limited reporting on the evaluation to identify LMB with better thermal resistance. LMB consists of the northern LMB (Micropterus salmoides salmoides, NLMB) and the Florida LMB (Micropterus salmoides floridanus, FLMB). Due to their different geographical distributions, it has been suggested that FLMB exhibit better thermal resistance compared to NLMB. In this study, NLMB and FLMB were subjected to thermal stress for 3 h (acute) and 60 d (chronic) at 33 °C, respectively. Subsequently, the variations of 12 candidate biomarkers between NLMB and FLMB were analyzed. Exposure to acute thermal stress significantly increased plasma cortisol, blood glucose, and lactate levels; activities of superoxide dismutase (SOD), glutathione peroxidase (GPX), catalase (CAT), glucose kinase (GK), pyruvate kinase (PK), lactate dehydrogenase (LDH), and glucose 6 phosphatase (G6Pase); and the expressions of hsp70 and hsp90 in both NLMB and FLMB (p < 0.05). Compared to NLMB, FLMB exhibited a lower plasma cortisol level and a higher expression of hsp90 under acute thermal stress (p < 0.05). Exposure to chronic thermal stress significantly increased plasma cortisol and blood glucose levels, as well as activities of GK, PK, LDH, and G6Pase, as well as expressions of hsp70 and hsp90 in both NLMB and FLMB (p < 0.05). Additionally, FLMB showed a lower expression of hsp70 compared to NLMB (p < 0.05). In conclusion, our results showed that LMB with lower plasma cortisol level and higher expression of hsp90 under acute thermal stress, as well as lower expression of hsp70 under chronic thermal stress were suggested to have better thermal resistance. Our study provides valuable information for identifying and breeding LMB varieties with better thermal resistance in the future.

Environmental specificity of karst cave habitats evidenced by diverse symbiotic bacteria in Opiliones

BACKGROUND

Karst caves serve as natural laboratories, providing organisms with extreme and constant conditions that promote isolation, resulting in a genetic relationship and living environment that is significantly different from those outside the cave. However, research on cave creatures, especially Opiliones, remains scarce, with most studies focused on water, soil, and cave sediments.

RESULTS

The structure of symbiotic bacteria in different caves were compared, revealing significant differences. Based on the alpha and beta diversity, symbiotic bacteria abundance and diversity in the cave were similar, but the structure of symbiotic bacteria differed inside and outside the cave. Microorganisms in the cave play an important role in material cycling and energy flow, particularly in the nitrogen cycle. Although microbial diversity varies inside and outside the cave, Opiliones in Beijing caves and Hainan Island exhibited a strong similarity, indicating that the two environments share commonalities.

CONCLUSIONS

The karst cave environment possesses high microbial diversity and there are noticeable differences among different caves. Different habitats lead to significant differences in the symbiotic bacteria in Opiliones inside and outside the cave, and cave microorganisms have made efforts to adapt to extreme environments. The similarity in symbiotic bacteria community structure suggests a potential similarity in host environments, providing an explanation for the appearance of Sinonychia martensi in caves in the north.

A systematic review of approaches to assess fish health responses to anthropogenic threats in freshwater ecosystems

Anthropogenic threats such as water infrastructure, land-use changes, overexploitation of fishes and other biological resources, invasive species and climate change present formidable challenges to freshwater biodiversity. Historically, management of fish and fishery species has largely been based on studies of population- and community-level dynamics; however, the emerging field of conservation physiology promotes the assessment of individual fish health as a key management tool. Fish health is highly sensitive to environmental disturbances and is also a fundamental driver of fitness, with implications for population dynamics such as recruitment and resilience. However, the mechanistic links between particular anthropogenic disturbances and changes in fish health, or impact pathways, are diverse and complex. The diversity of ways in which fish health can be measured also presents a challenge for researchers deciding on methods to employ in studies seeking to understand the impact of these threats. In this review, we aim to provide an understanding of the pathway through which anthropogenic threats in freshwater ecosystems impact fish health and the ways in which fish health components impacted by anthropogenic threats can be assessed. We employ a quantitative systematic approach to a corpus of papers related to fish health in freshwater and utilize a framework that summarizes the impact pathway of anthropogenic threats through environmental alterations and impact mechanisms that cause a response in fish health. We found that land-use changes were the most prolific anthropogenic threat, with a range of different health metrics being suitable for assessing the impact of this threat. Almost all anthropogenic threats impacted fish health through two or more impact pathways. A robust understanding of the impact pathways of anthropogenic threats and the fish health metrics that are sensitive to these threats is crucial for fisheries managers seeking to undertake targeted management of freshwater ecosystems.

Sublethal effects of chlorantraniliprole on immunity in Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae): Promote encapsulation by upregulating a heat shock protein 70 family gene SfHSP68.1

As an agricultural pest, the fall armyworm (FAW), Spodoptera frugiperda, poses a severe threat to agriculture in China. Chlorantraniliprole has been widely used to control this pest. In our previous studies, we discovered that LD10, LD20, and LD30 chlorantraniliprole promoted encapsulation in the 4th instar larvae of the FAW, with LD30 chlorantraniliprole having the most significant effect. To further investigate the molecular mechanism underlying the sublethal effects of chlorantraniliprole on encapsulation in the FAW, this study conducted the effects of encapsulation in 4th instar larvae of the FAW exposed to LD30 chlorantraniliprole. Then, we analyzed the transcriptome of the FAW hemolymph treated with LD30 chlorantraniliprole and identified genes related to encapsulation using RNAi. Our results showed that the encapsulation in the FAW was enhanced at 6, 12, 18, 24, and 48 h after exposure to LD30 chlorantraniliprole. Additionally, LD30 chlorantraniliprole significantly affected the expression of certain immune-related genes, with the heat shock protein 70 family gene SfHSP68.1 showing the most significant upregulation. Subsequent interference with SfHSP68.1 resulted in a significant inhibition of encapsulation in FAW. These findings suggested that LD30 chlorantraniliprole can promote encapsulation in the FAW by upregulating SfHSP68.1 expression. This study provides valuable insights into the sublethal effects of chlorantraniliprole on encapsulation in the FAW and the interaction between encapsulation and heat shock proteins (HSPs).

Sensitivity of amphibian embryos to timing and magnitude of present and future thermal extremes

Ongoing climate change is increasing the frequency and intensity of extreme temperature events. Unlike the gradual increase on average environmental temperatures, these short-term and unpredictable temperature extremes impact population dynamics of ectotherms through their effect on individual survival. While previous research has predominantly focused on the survival rate of terrestrial embryos under acute heat stress, less attention has been dedicated to the nonlethal effects of ecologically realistic timing and magnitude of temperature extremes on aquatic embryos. In this study, we investigated the influence of the timing and magnitude of current and projected temperature extremes on embryonic life history traits and hatchling behavior in the alpine newt, Ichthyosaura alpestris. Using a factorial experiment under controlled laboratory conditions, we exposed 3- or 10-day-old embryos to different regimes of extreme temperatures for 3 days. Our results show that exposure to different extreme temperature regimes led to a shortened embryonic development time and an increase in hatchling length, while not significantly affecting embryonic survival. The duration of development was sensitive to the timing of temperature extremes, as early exposure accelerated embryo development. Exposure to temperature extremes during embryonic development heightened the exploratory activity of hatched larvae. We conclude that the timing and magnitude of ecologically realistic temperature extremes during embryogenesis have nonlethal effects on life history and behavioral traits. This suggests that species' vulnerability to climate change might be determined by other ecophysiological traits beyond embryonic thermal tolerance in temperate pond-breeding amphibians.

Interactions between chaperone and energy storage networks during the evolution of Legionella pneumophila under heat shock

Waterborne transmission of the bacterium Legionella pneumophila has emerged as a major cause of severe nosocomial infections of major public health impact. The major route of transmission involves the uptake of aerosolized bacteria, often from the contaminated hot water systems of large buildings. Public health regulations aimed at controlling the mesophilic pathogen are generally concerned with acute pasteurization and maintaining high temperatures at the heating systems and throughout the plumbing of hot water systems, but L. pneumophila is often able to survive these treatments due to both bacterium-intrinsic and environmental factors. Previous work has established an experimental evolution system to model the observations of increased heat resistance in repeatedly but unsuccessfully pasteurized L. pneumophila populations. Here, we show rapid fixation of novel alleles in lineages selected for resistance to heat shock and shifts in mutational profile related to increases in the temperature of selection. Gene-level and nucleotide-level parallelisms between independently-evolving lineages show the centrality of the DnaJ/DnaK chaperone system in the heat resistance of L. pneumophila. Inference of epistatic interactions through reverse genetics shows an unexpected interaction between DnaJ/DnaK and the polyhydroxybutyrate-accumulation energy storage mechanism used by the species to survive long-term starvation in low-nutrient environments.

Temperature Effects on Expression Levels of hsp Genes in Eggs and Second-Stage Juveniles of Meloidogyne hapla Chitwood, 1949

Meloidogyne hapla is one of the most important nematode pathogens. It is a sedentary, biotrophic parasite of plants that overwinters in the soil or in diseased roots. The development of M. hapla is temperature dependent. Numerous studies have been performed on the effect of temperature on the development of M. hapla, but only a few of them analyzed the heat shock protein (hsp) genes. The aim of the study was to perform expression profiling of eight hsp genes (Mh-hsp90, Mh-hsp1, Mh-hsp4, Mh-hsp6, Mh-hsp60, Mh-dnj19, Mh-hsp43, and Mh-hsp12.2) at two development stages of M. hapla, i.e., in eggs and second-stage juveniles (J2). The eggs and J2 were incubated under cold stress (5 °C), heat stress (35 °C, 40 °C), and non-stress (10 °C, 20 °C, and 30 °C) conditions. Expression profiling was performed by qPCR. It was demonstrated that only two genes, Mh-hsp60 and Mh-dnj19, have been upregulated by heat and cold stress at both development stages. Heat stress upregulated the expression of more hsp genes than cold stress did. The level of upregulation of most hsp genes was more marked in J2 than in eggs. The obtained results suggest that the Mh-hsp90 and Mh-hsp1 genes can be used as bioindicators of environmental impacts on nematodes of the Meloidogyne genus.

The pyrexia channel remodels egg-laying of Liriomyza huidobrensis in response to temperature change

BACKGROUND

The pea leafminer, Liriomyza huidobrensis, is one of the most important insect pests on vegetables and ornamentals. The survival and egg-laying behavior of leafminers are markedly affected by the environment temperature. However, the mechanisms underlying the relationship between egg-laying and temperature are still largely unknown.

RESULTS

Here, we find that leafminers have evolved an adaptive strategy to overcome the stress from high or low temperature by regulating oviposition-punching plasticity. We further show that this oviposition-punching plasticity is mediated by the expression of pyx in the ovipositor when subjected to disadvantageous temperature. Specifically, down-regulation of pyx expression in leafminers under low temperature stress led to a significant decrease in the swing numbers of ovipositor and puncture area of the egg spot, and consequently the lower amount of egg-laying compared to leafminers at ambient temperature. Conversely, activation of pyx expression under high temperature stress increased the swing numbers and puncture area, still resulting in a reduction of egg-laying amount.

CONCLUSION

Thereby, leafminers are able to coordinate pyx channel expression level and accordingly depress the oviposition. Our study uncovers a molecular mechanism underlying the adaptive strategy in insects that can avoid disadvantageous temperature for reproducing offspring. © 2024 Society of Chemical Industry.

Responses of the coral reef cryptobiome to environmental gradients in the Red Sea

An essential component of the coral reef animal diversity is the species hidden in crevices within the reef matrix, referred to as the cryptobiome. These organisms play an important role in nutrient cycling and provide an abundant food source for higher trophic levels, yet they have been largely overlooked. Here, we analyzed the distribution patterns of the mobile cryptobiome (>2000 μm) along the latitudinal gradient of the Saudi Arabian coast of the Red Sea. Analysis was conducted based on 54 Autonomous Reef Monitoring Structures. We retrieved a total of 5273 organisms, from which 2583 DNA sequences from the mitochondrially encoded cytochrome c oxidase I were generated through sanger sequencing. We found that the cryptobiome community is variable over short geographical distances within the basin. Regression tree models identified sea surface temperature (SST), percentage cover of hard coral and turf algae as determinant for the number of operational taxonomic units present per Autonomous Reef Monitoring Structures (ARMS). Our results also show that the community structure of the cryptobiome is associated with the energy available (measured as photosynthetic active radiation), sea surface temperature, and nearby reef habitat characteristics (namely hard corals, turf and macroalgae). Given that temperature and reef benthic characteristics affect the cryptobiome, current scenarios of intensive climate change are likely to modify this fundamental biological component of coral reef functioning. However, the trajectory of change is unknow and can be site specific, as for example, diversity is expected to increase above SST of 28.5°C, and with decreasing hard coral and turf cover. This study provides a baseline of the cryptobenthic community prior to major coastal developments in the Red Sea to be used for future biodiversity studies and monitoring projects. It can also contribute to better understand patterns of reef biodiversity in a period where Marine Protected Areas are being discussed in the region.

Comparative evaluation of three real-time polymerase chain reaction assays to detect Myxobolus cerebralis

OBJECTIVE

We sought to evaluate accurate and reproducible detection of Myxobolus cerebralis (Mc), the causative agent of whirling disease, by using nested polymerase chain reaction (nPCR) and three previously established real-time quantitative PCR (qPCR) assays: K18S (Kelley 18S), C18S (Cavender 18S), and Hsp70 (heat shock protein 70). We used a "fit for purpose" approach combined with intra- and interlaboratory testing to identify a molecular testing method that would be equivalent to the currently accepted nPCR procedure for Mc.

METHODS

Assay performance was compared using a combination of intra- and interlaboratory testing that used synthetic gBlocks along with naturally and experimentally infected fish tissue. North American isolates representing geographically distinct locations were also tested using all three assays.

RESULT

The K18S and C18S assays exhibited high assay sensitivity, intra- and interlaboratory repeatability of sample replicates, and reproducible identification of all test samples across multiple laboratories. In contrast, the Hsp70 assay failed to detect several positive samples at low DNA concentrations during intra- and interlaboratory testing. The K18S assay was the only procedure that demonstrated perfect detection accuracy when testing geographically distinct Mc isolates. Results demonstrated the K18S assay is robust under variable test conditions, is more accurate than the C18S and Hsp70 assays, and provides detection capabilities equivalent to those of the currently accepted nPCR confirmation assay "gold standard" that is described in the American Fisheries Society-Fish Health Section (AFS-FHS) Blue Book.

CONCLUSION

The "fit for purpose" approach and preliminary completion of the World Organization for Animal Health validation pathway demonstrate that the K18S assay provides an alternate method for Mc testing. This work provides the foundation for acceptance of the K18S assay into the AFS-FHS Blue Book as a standardized test procedure for Mc.

HSPA4 upregulation induces immune evasion via ALKBH5/CD58 axis in gastric cancer

INTRODUCTION

Gastric cancer (GC) is one of the leading causes of cancer-related death worldwide. Recently, targeted therapies including PD1 (programmed cell death 1) antibodies have been used in advanced GC patients. However, identifying new biomarker for immunotherapy is still urgently needed. The objective of this study is to unveil the immune evasion mechanism of GC cells and identify new biomarkers for immune checkpoint blockade therapy in patients with GC.

METHODS

Coimmunoprecipitation and meRIP were performed to investigate the mechanism of immune evasion of GC cells. Cocuture system was established to evaluate the cytotoxicity of cocultured CD8+ T cells. The clinical significance of HSPA4 upregulation was analyzed by multiplex fluorescent immunohistochemistry staining in GC tumor tissues.

RESULTS

Histone acetylation causes HSPA4 upregulation in GC tumor tissues. HSPA4 upregulation increases the protein stability of m6A demethylase ALKBH5. ALKBH5 decreases CD58 in GC cells through m6A methylation regulation. The cytotoxicity of CD8+ T cells are impaired and PD1/PDL1 axis is activated when CD8+ T cells are cocultured with HSPA4 overexpressed GC cells. HSPA4 upregulation is associated with worse 5-year overall survival of GC patients receiving only surgery. It is an independent prognosis factor for worse survival of GC patients. In GC patients receiving the combined chemotherapy with anti-PD1 immunotherapy, HSPA4 upregulation is observed in responders compared with non-responders.

CONCLUSION

HSPA4 upregulation causes the decrease of CD58 in GC cells via HSPA4/ALKBH5/CD58 axis, followed by PD1/PDL1 activation and impairment of CD8+ T cell's cytotoxicity, finally induces immune evasion of GC cells. HSPA4 upregulation is associated with worse overall survival of GC patients with only surgery. Meanwhile, HSPA4 upregulation predicts for better response in GC patients receiving the combined immunotherapy.

Geographic origin shapes the adaptive divergences of Rotaria rotatoria (Rotifera, Bdelloidea) to thermal stress: Insights from ecology and transcriptomics

Global warming has raised concerns regarding the potential impact on aquatic biosafety and health. To illuminate the adaptive mechanisms of bdelloid rotifers in response to global warming, the ecological and transcriptomic characteristics of two strains (HX and ZJ) of Rotaria rotatoria were investigated at 25°C and 35°C. Our results showed an obvious genetic divergence between the two geographic populations. Thermal stress significantly reduced the average lifespan of R. rotatoria in both strains, but increased the offspring production in the ZJ strain. Furthermore, the expression levels of genes Hsp70 were significantly upregulated in the HX strain, while GSTo1 and Cu/Zn-SOD were on the contrary. In the ZJ strain, the expression levels of genes Hsp70, CAT2, and GSTo1 were upregulated under thermal stress. Conversely, a significant decrease in the expression level of the Mn-SOD gene was observed in the ZJ strain under thermal stress. Transcriptomic profiling analysis revealed a total of 105 and 5288 differentially expressed genes (DEGs) in the HX and ZJ strains under thermal stress, respectively. The PCA results showed clear differences in gene expression pattern between HX and ZJ strains under thermal stress. Interestingly, compared to the HX strain, numerous downregulated DEGs in the ZJ strain were enriched into pathways related to metabolism under thermal stress, suggesting that rotifers from the ZJ strain prioritize resource allocation to reproduction by suppressing costly metabolic processes. This finding is consistent with the life table results. This study provides new insights into the adaptive evolution of aquatic animals in the context of global climate change.

Significance of dietary quinoa husk (Chenopodium quinoa) in gene regulation for stress mitigation in fish

The persistent challenges posed by pollution and climate change are significant factors disrupting ecosystems, particularly aquatic environments. Numerous contaminants found in aquatic systems, such as ammonia and metal toxicity, play a crucial role in adversely affecting aquaculture production. Against this backdrop, fish feed was developed using quinoa husk (the byproduct of quinoa) as a substitute for fish meal. Six isonitrogenous diets (30%) and isocaloric diets were formulated by replacing fish meal with quinoa husk at varying percentages: 0% quinoa (control), 15, 20, 25, 30 and 35%. An experiment was conducted to explore the potential of quinoa husk in replacing fish meal and assess its ability to mitigate ammonia and arsenic toxicity as well as high-temperature stress in Pangasianodon hypophthalmus. The formulated feed was also examined for gene regulation related to antioxidative status, immunity, stress proteins, growth regulation, and stress markers. The gene regulation of sod, cat, and gpx in the liver was notably upregulated under concurrent exposure to ammonia, arsenic, and high-temperature (NH3 + As + T) stress. However, quinoa husk at 25% downregulated sod, cat, and gpx expression compared to the control group. Furthermore, genes associated with stress proteins HSP70 and DNA damage-inducible protein (DDIP) were significantly upregulated in response to stressors (NH3 + As + T), but quinoa husk at 25% considerably downregulated HSP70 and DDIP to mitigate the impact of stressors. Growth-responsive genes such as myostatin (MYST) and somatostatin (SMT) were remarkably downregulated, whereas growth hormone receptor (GHR1 and GHRβ), insulin-like growth factors (IGF1X, IGF2X), and growth hormone gene were significantly upregulated with quinoa husk at 25%. The gene expression of apoptosis (Caspase 3a and Caspase 3b) and nitric oxide synthase (iNOS) were also noticeably downregulated with quinoa husk (25%) reared under stressful conditions. Immune-related gene expression, including immunoglobulin (Ig), toll-like receptor (TLR), tumor necrosis factor (TNFα), and interleukin (IL), strengthened fish immunity with quinoa husk feed. The results revealed that replacing 25% of fish meal with quinoa husk could improve the gene regulation of P. hypophthalmus involved in mitigating ammonia, arsenic, and high-temperature stress in fish.

Chromosome-level genome assembly of the aster leafhopper (Macrosteles quadrilineatus) reveals the role of environment and microbial symbiosis in shaping pest insect genome evolution

Leafhoppers comprise over 20,000 plant-sap feeding species, many of which are important agricultural pests. Most species rely on two ancestral bacterial symbionts, Sulcia and Nasuia, for essential nutrition lacking in their phloem and xylem plant sap diets. To understand how pest leafhopper genomes evolve and are shaped by microbial symbioses, we completed a chromosomal-level assembly of the aster leafhopper's genome (ALF; Macrosteles quadrilineatus). We compared ALF's genome to three other pest leafhoppers, Nephotettix cincticeps, Homalodisca vitripennis, and Empoasca onukii, which have distinct ecologies and symbiotic relationships. Despite diverging ~155 million years ago, leafhoppers have high levels of chromosomal synteny and gene family conservation. Conserved genes include those involved in plant chemical detoxification, resistance to various insecticides, and defence against environmental stress. Positive selection acting upon these genes further points to ongoing adaptive evolution in response to agricultural environments. In relation to leafhoppers' general dependence on symbionts, species that retain the ancestral symbiont, Sulcia, displayed gene enrichment of metabolic processes in their genomes. Leafhoppers with both Sulcia and its ancient partner, Nasuia, showed genomic enrichment in genes related to microbial population regulation and immune responses. Finally, horizontally transferred genes (HTGs) associated with symbiont support of Sulcia and Nasuia are only observed in leafhoppers that maintain symbionts. In contrast, HTGs involved in non-symbiotic functions are conserved across all species. The high-quality ALF genome provides deep insights into how host ecology and symbioses shape genome evolution and a wealth of genetic resources for pest control targets.

The small heat shock protein Hsp20.8 imparts tolerance to high temperatures in the leafminer fly, Liriomyza trifolii (Diptera: Agtomyzidae)

As an environmental factor, temperature impacts the distribution of species and influences interspecific competition. The molecular chaperones encoded by small heat shock proteins (sHsps) are essential for rapid, appropriate responses to environmental stress. This study focuses on Hsp20.8, which encodes a temperature-responsive sHsp in Liriomyza trifolii, an insect pest that infests both agricultural and ornamental crops. Hsp20.8 expression was highest at 39℃ in L. trifolii pupae and adults, and expression levels were greater in pupae than in adults. Recombinant Hsp20.8 was expressed in Escherichia coli and conferred a higher survival rate than the empty vector to bacterial cells exposed to heat stress. RNA interference experiments were conducted using L. trifolii adults and prepupae and the knockdown of Hsp20.8 expression increased mortality in L. trifolii during heat stress. The results expand our understanding of sHsp function in Liriomyza spp. and the ongoing adaptation of this pest to climate change. In addition, this study is also important for predicting the distribution of invasive species and proposing new prevention and control strategies based on temperature adaptation.

Gills de novo assembly reveals oxidative stress, unfolded protein, and immune response on red cusk-eel (Genypterus chilensis) under thermal stress

The heat waves on the South Pacific coast could lead to thermal stress in native fish. The red cusk-eel (Genypterus chilensis) is relevant for Chilean artisanal fisheries and aquaculture diversification. This study examined the effect of high-temperature stress in the gills of G. chilensis in control (14 °C) and high-temperature stress (19 °C) conditions. High-temperature stress induces a significant increase in gills cortisol levels. Additionally, oxidative damage was observed in gills (protein carbonylation and lipoperoxidation). RNA-seq data was used to build the first transcriptome assembly of gills in this species (23,656 annotated transcripts). A total of 1138 down-regulated and 1531 up-regulated transcripts were observed in response to high-temperature stress in gills. The enrichment analysis showed immune response and replication enriched processes (on down-regulated transcripts), and processes related to the folding of proteins, endoplasmic reticulum, and transporter activity (on up-regulated transcripts). The present study showed how gills could be affected by high-temperature stress.

The protein map of the protozoan parasite Leishmania (Leishmania) amazonensis, Leishmania (Viannia) braziliensis and Leishmania (Leishmania) infantum during growth phase transition and temperature stress

Leishmania parasites cause a spectrum of diseases termed leishmaniasis, which manifests in two main clinical forms, cutaneous and visceral leishmaniasis. Leishmania promastigotes transit from proliferative exponential to quiescent stationary phases inside the insect vector, a relevant step that recapitulates early molecular events of metacyclogenesis. During the insect blood meal of the mammalian hosts, the released parasites interact initially with the skin, an event marked by temperature changes. Deep knowledge on the molecular events activated during Leishmania-host interactions in each step is crucial to develop better therapies and to understand the pathogenesis. In this study, the proteomes of Leishmania (Leishmania) amazonensis (La), Leishmania (Viannia) braziliensis (Lb), and Leishmania (Leishmania) infantum (syn L. L. chagasi) (Lc) were analyzed using quantitative proteomics to uncover the proteome modulation in three different conditions related to growth phases and temperature shifts: 1) exponential phase (Exp); 2) stationary phase (Sta25) and; 3) stationary phase subjected to heat stress (Sta34). Functional validations were performed using orthogonal techniques, focusing on α-tubulin, gp63 and heat shock proteins (HSPs). Species-specific and condition-specific modulation highlights the plasticity of the Leishmania proteome, showing that pathways related to metabolism and cytoskeleton are significantly modulated from exponential to stationary growth phases, while protein folding, unfolded protein binding, signaling and microtubule-based movement were differentially altered during temperature shifts. This study provides an in-depth proteome analysis of three Leishmania spp., and contributes compelling evidence of the molecular alterations of these parasites in conditions mimicking the interaction of the parasites with the insect vector and vertebrate hosts. SIGNIFICANCE: Leishmaniasis disease manifests in two main clinical forms according to the infecting Leishmania species and host immune responses, cutaneous and visceral leishmaniasis. In Brazil, cutaneous leishmaniasis (CL) is associated with L. braziliensis and L. amazonensis, while visceral leishmaniasis, also called kala-azar, is caused by L. infantum. Leishmania parasites remodel their proteomes during growth phase transition and changes in their mileu imposed by the host, including temperature. In this study, we performed a quantitative mass spectrometry-based proteomics to compare the proteome of three New world Leishmania species, L. amazonensis (La), L. braziliensis (Lb) and L. infantum (syn L. chagasi) (Lc) in three conditions: a) exponential phase at 25 °C (Exp); b) stationary phase at 25 °C (Sta25) and; c) stationary phase subjected to temperature stress at 34 °C (Sta34). This study provides an in-depth proteome analysis of three Leishmania spp. with varying pathophysiological outcomes, and contributes compelling evidence of the molecular alterations of these parasites in conditions mimicking the interaction of the parasites with the insect vector and vertebrate hosts.

Fungal heat shock proteins: molecular phylogenetic insights into the host takeover

Heat shock proteins are constitutively expressed chaperones induced by cellular stress, such as changes in temperature, pH, and osmolarity. These proteins, present in all organisms, are highly conserved and are recruited for the assembly of protein complexes, transport, and compartmentalization of molecules. In fungi, these proteins are related to their adaptation to the environment, their evolutionary success in acquiring new hosts, and regulation of virulence and resistance factors. These characteristics are interesting for assessment of the host adaptability and ecological transitions, given the emergence of infections by these microorganisms. Based on phylogenetic inferences, we compared the sequences of HSP9, HSP12, HSP30, HSP40, HSP70, HSP90, and HSP110 to elucidate the evolutionary relationships of different fungal organisms to suggest evolutionary patterns employing the maximum likelihood method. By the different reconstructions, our inference supports the hypothesis that these classes of proteins are associated with pathogenic gains against endothermic hosts, as well as adaptations for phytopathogenic fungi.

How do biomarkers dance? Specific moves of defense and damage biomarkers for biological interpretation of dose-response model trends

Omics studies are currently increasingly used in ecotoxicology to highlight the induction of known or novel biomarkers when organisms are exposed to contaminants. Although it is virtually impossible to identify all biomarkers from all organisms, biomarkers can be grouped as defense or damage biomarkers, exhibiting a limited number of response trends. Our working hypothesis is that defense and damage biomarkers follow different dose-response patterns. A meta-analysis of 156 articles and 2595 observations of dose-response curves of defense and damage biomarkers was carried out in order to characterize the response trends of these biological parameters in a large panel of living organisms (18 phyla) exposed to inorganic or organic contaminants (176 in total). Using multinomial logistic regression models, defense biomarkers were found to describe biphasic responses (bell- and U-shaped) to a greater extent (2.5 times) than damage biomarkers. In contrast, damage biomarkers varied mainly monotonically (decreasing or increasing), representing 85% of the observations. Neither the nature of the contaminant nor the type of organisms belonging to 4 kingdoms, influence these specific responses. This result suggests that cellular defense and damage mechanisms are not specific to stressors and are conserved throughout life. Trend analysis of dose-response models as a biological interpretation of biomarkers could thus be a valuable way to exploit large omics datasets.

Cutaneous Evaporative Water Loss in Lizards Changes Immediately with Temperature

AbstractCutaneous evaporative water loss (CEWL) makes up a significant portion of total evaporative water loss in many terrestrial vertebrates. CEWL changes on evolutionary and acclimatory timescales in response to temperature and humidity. However, the lability of CEWL on acute timescales is unknown. To examine this, we increased or decreased body temperatures of western fence lizards (Sceloporus occidentalis) over a 15-min period while continuously recording CEWL with a handheld evaporimeter. CEWL increased in response to heating and decreased in response to cooling on the order of seconds. However, CEWL was different between heating and cooling groups at a common body temperature. We observed the same positive relationship between CEWL and body temperature, as well as the difference in CEWL between treatments, for deceased lizards that we opportunistically measured. However, deceased lizards had more extreme CEWL values for any given body temperature and treatment. Overall, our results suggest that both structural traits and active physiological processes likely influence the rates and plasticity of CEWL.

Characterization of genes encoding heat shock proteins reveals a differential response to temperature in two geographic populations of Liriomyza trifolii (Diptera: Agromyzidae)

Liriomyza trifolii is a significant, invasive pest that damages horticultural crops and vegetables. The distribution of L. trifolii is influenced by temperature, and prior research has demonstrated that variations in thermal adaptability differ among geographic populations of the insect. Heat shock proteins (Hsps) are involved in adaptation to temperatures; however, the underlying molecular mechanism for thermal adaption in different L. trifolii populations remains unclear. This study examines the temperature adaptability of two L. trifolii populations from Hainan (HN) and Jiangsu (JS) provinces. The results indicate that the HN population has a higher survival rate and a higher critical thermal maximum (CTmax) than the JS population under high temperature stress. Transcriptome data at 42 °C revealed that the JS population has more differentially expressed genes (DEGs) than the HN population, while the HN population has more upregulated DEGs. The two populations were similar in functional annotation of DEGs, and a large number of Hsps were upregulated. However, the HN population had larger numbers and higher expression levels of Hsps during heat stress as compared to the JS population. Additionally, the expression patterns of differentially expressed Hsps varied between the HN and JS populations in response to different elevated temperatures. Notably, the transcription levels of Hsp70s were higher in the HN population as compared to the JS population, while the expression level of genes encoding small heat shock proteins was higher in the JS population. These findings have significant scientific value in understanding the underlying mechanism of temperature adaption in L. trifolii and provide a fresh perspective on the distribution of this invasive pest.

Two heat shock cognate 70 genes involved in spermatogenesis regulate the male fertility of Zeugodacus cucurbitae, as potential targets for pest control

The melon fly Zeugodacus cucurbitae Coquillett (Diptera: Tephritidae) is an agricultural quarantine pest threatening fruit and vegetable production. Heat shock cognate 70 (Hsc70), which is a homolog of the heat shock protein 70 (Hsp70), was first discovered in mice testes and plays an important role in spermatogenesis. In this study, we identified and cloned five Hsc70 genes from melon fly, namely ZcHsc70_1/2/3/4/5. Phylogenetic analysis showed that these proteins are closely related to Hsc70s from other Diptera insects. Spatiotemporal expression analysis showed that ZcHsc70_1 and ZcHsc70_2 are highly expressed in Z. cucurbitae testes. Fluorescence in situ hybridization further demonstrated that ZcHsc70_1 and ZcHsc70_2 are expressed in the transformation and maturation regions of testes, respectively. Moreover, RNA interference-based suppression of ZcHsc70_1 or ZcHsc70_2 resulted in a significant decrease of 74.61% and 63.28% in egg hatchability, respectively. Suppression of ZcHsc70_1 expression delayed the transformation of sperm cells to mature sperms. Meanwhile, suppression of ZcHsc70_2 expression decreased both sperm cells and mature sperms by inhibiting the meiosis of spermatocytes. Our findings show that ZcHsc70_1/2 regulates spermatogenesis and further affects the male fertility in the melon fly, showing potential as targets for pest control in sterile insect technique by genetic manipulation of males.

Selection Signal Analysis Reveals Hainan Yellow Cattle Are Being Selectively Bred for Heat Tolerance

Hainan yellow cattle are indigenous Zebu cattle from southern China known for their tolerance of heat and strong resistance to disease. Generations of adaptation to the tropical environment of southern China and decades of artificial breeding have left identifiable selection signals in their genomic makeup. However, information on the selection signatures of Hainan yellow cattle is scarce. Herein, we compared the genomes of Hainan yellow cattle with those of Zebu, Qinchuan, Nanyang, and Yanbian cattle breeds by the composite likelihood ratio method (CLR), Tajima's D method, and identifying runs of homozygosity (ROHs), each of which may provide evidence of the genes responsible for heat tolerance in Hainan yellow cattle. The results showed that 5210, 1972, and 1290 single nucleotide polymorphisms (SNPs) were screened by the CLR method, Tajima's D method, and ROH method, respectively. A total of 453, 450, and 325 genes, respectively, were identified near these SNPs. These genes were significantly enriched in 65 Gene Ontology (GO) functional terms and 11 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways (corrected p < 0.05). Five genes-Adenosylhomocysteinase-like 2, DnaJ heat shock protein family (Hsp40) member C3, heat shock protein family A (Hsp70) member 1A, CD53 molecule, and zinc finger and BTB domain containing 12-were recognized as candidate genes associated with heat tolerance. After further functional verification of these genes, the research results may benefit the understanding of the genetic mechanism of the heat tolerance in Hainan yellow cattle, which lay the foundation for subsequent studies on heat stress in this breed.

Protein-folding chaperones predict structure-function relationships and cancer risk in BRCA1 mutation carriers

Predicting the risk of cancer mutations is critical for early detection and prevention, but differences in allelic severity of human carriers confound risk predictions. Here, we elucidate protein folding as a cellular mechanism driving differences in mutation severity of tumor suppressor BRCA1. Using a high-throughput protein-protein interaction assay, we show that protein-folding chaperone binding patterns predict the pathogenicity of variants in the BRCA1 C-terminal (BRCT) domain. HSP70 selectively binds 94% of pathogenic BRCA1-BRCT variants, most of which engage HSP70 more than HSP90. Remarkably, the magnitude of HSP70 binding linearly correlates with loss of folding and function. We identify a prevalent class of human hypomorphic BRCA1 variants that bind moderately to chaperones and retain partial folding and function. Furthermore, chaperone binding signifies greater mutation penetrance and earlier cancer onset in the clinic. Our findings demonstrate the utility of chaperones as quantitative cellular biosensors of variant folding, phenotypic severity, and cancer risk.

Genome-Wide Identification and Transcriptome Analysis of the Hsp70 Gene Family in Monodonta labio Reveals Its Role in Response to Nanoplastics Stress

For marine invertebrates, the disruption of organismal physiology and behavior by nanoplastics (NPs) has been extensively reported. Heat shock proteins (Hsps) are important for redundant protein breakdown, environmental changes, and intracellular protein transport. An exhaustive identification of Hsp70 genes and an experiment where different concentrations of NPs were stressed were performed to study how Hsp70 genes respond to NPs stress in Monodonta labio. Our results identified 15 members of Hsp70 within the genome of M. labio and provided insights into their responses to different concentrations of acute NP stress. Phylogenetic analyses revealed extensive amplification of the Hsp70 genes from the Hsc70 subfamily, with gene duplication events. As a result of NP stress, five of fifteen genes showed significant upregulation or downregulation. Three Hsp70 genes were highly expressed at an NP concentration of 0.1 mg/L, and no genes were downregulated. At 10 mg/L, they showed significant upregulation of two genes and significant downregulation of two genes. At 1 mg/L treatment, three genes were significantly downregulated, and no genes were significantly upregulated. Moreover, a purifying selection was revealed using a selection test conducted on duplicate gene pairs, indicating functional redundancy. This work is the first thorough examination of the Hsp70s in Archaeogastropoda. The findings improve knowledge of Hsp70s in molluscan adaptation to NP stress and intertidal living and offer essential data for the biological study of M. labio.

Getting around the roundworms: Identifying knowledge gaps and research priorities for the ascarids

The ascarids are a large group of parasitic nematodes that infect a wide range of animal species. In humans, they cause neglected diseases of poverty; many animal parasites also cause zoonotic infections in people. Control measures include hygiene and anthelmintic treatments, but they are not always appropriate or effective and this creates a continuing need to search for better ways to reduce the human, welfare and economic costs of these infections. To this end, Le Studium Institute of Advanced Studies organized a two-day conference to identify major gaps in our understanding of ascarid parasites with a view to setting research priorities that would allow for improved control. The participants identified several key areas for future focus, comprising of advances in genomic analysis and the use of model organisms, especially Caenorhabditis elegans, a more thorough appreciation of the complexity of host-parasite (and parasite-parasite) communications, a search for novel anthelmintic drugs and the development of effective vaccines. The participants agreed to try and maintain informal links in the future that could form the basis for collaborative projects, and to co-operate to organize future meetings and workshops to promote ascarid research.

Heat-shock protein 90 alleviates oxidative stress and reduces apoptosis in liver of Seriola aureovittata (yellowtail kingfish) under high-temperature stress

Hsp90s are molecular chaperones that enhance fish tolerance to high-temperature stress. However, the function of Hsp90s in Seriola aureovittata (yellowtail kingfish) under high-temperature stress remains largely unknown. Here, two Hsp90 isoforms were identified in S. aureovittata by bioinformatics analysis: SaHsp90α and SaHsp90β. The coding sequence of SaHsp90α was 2193-bp long and encoded a polypeptide of 730 amino acids; SaHsp90β was 2178-bp long and encoded a polypeptide of 725 amino acids. SaHsp90α and SaHsp90β both contained a HATPase domain and a HSP90 domain. Their transcripts were detected in all examined S. aureovittata tissues, with relatively high levels in the gonads, head kidney, and intestine. During high-temperature stress at 28 °C, the expression levels of SaHsp90α and SaHsp90β transcripts were significantly increased in liver. After simultaneously knocking down the expression of the SaHsp90s, there was a significant decrease in liver superoxide dismutase (SOD) activity and a remarkable increase of malondialdehyde content in liver after high-temperature stress. The expression levels of the key caspase family genes caspase-3 and caspase-7 were also significantly upregulated by high-temperature stress in SaHsp90-knockdown liver. TUNEL labeling demonstrated that the number of apoptotic cells significantly increased in the SaHsp90-knockdown group when high-temperature treatment lasted for 48 h. Protein-protein docking analysis predicted that SaHsp90α and SaHsp90β can bind to S. aureovittata SOD and survivin, which are key proteins for maintenance of redox homeostasis and inhibition of apoptosis. These findings demonstrate that SaHsp90α and SaHsp90β play a crucial role in resistance to high-temperature stress by regulating redox homeostasis and apoptosis in yellowtail kingfish.

Effects of petrogenic pollutants on North Atlantic and Arctic Calanus copepods: From molecular mechanisms to population impacts

Oil and gas industries in the Northern Atlantic Ocean have gradually moved closer to the Arctic areas, a process expected to be further facilitated by sea ice withdrawal caused by global warming. Copepods of the genus Calanus hold a key position in these cold-water food webs, providing an important energetic link between primary production and higher trophic levels. Due to their ecological importance, there is a concern about how accidental oil spills and produced water discharges may impact cold-water copepods. In this review, we summarize the current knowledge of the toxicity of petroleum on North Atlantic and Arctic Calanus copepods. We also review how recent development of high-quality transcriptomes from RNA-sequencing of copepods have identified genes regulating key biological processes, like molting, diapause and reproduction in Calanus copepods, to suggest linkages between exposure, molecular mechanisms and effects on higher levels of biological organization. We found that the available ecotoxicity threshold data for these copepods provide valuable information about their sensitivity to acute petrogenic exposures; however, there is still insufficient knowledge regarding underlying mechanisms of toxicity and the potential for long-term implications of relevance for copepod ecology and phenology. Copepod transcriptomics has expanded our understanding of how key biological processes are regulated in cold-water copepods. These advances can improve our understanding of how pollutants affect biological processes, and thus provide the basis for new knowledge frameworks spanning the effect continuum from molecular initiating events to adverse effects of regulatory relevance. Such efforts, guided by concepts such as adverse outcome pathways (AOPs), enable standardized and transparent characterization and evaluation of knowledge and identifies research gaps and priorities. This review suggests enhancing mechanistic understanding of exposure-effect relationships to better understand and link biomarker responses to adverse effects to improve risk assessments assessing ecological effects of pollutant mixtures, like crude oil, in Arctic areas.

Expression patterns of heat-shock genes during stopover and the trade-off between refueling and stress response in a passerine migrant

Migrating birds are often exposed to variable environments and face a multitude of stress exposures along their long-distance flights. During stopover refueling, migratory birds must balance the need to accumulate energy reserves to continue their migration with the need to respond to environmental and physiological stressors. We examined the gene expression patterns of different Heat Shock Proteins (HSPs) in migrating birds during stopover at different body condition states (lean vs. fat), to provide some first insights on the role of HSPs in bird migration and explore the concept of a trade-off between refueling and stress response. Our results showed upregulation of HSP expression at release that could be associated with muscle growth and increased cholesterol and lipid synthesis needed for birds to fuel their upcoming migration. On the other hand, during capture, upregulation of HSP5 could be attributed to physiological recovery from the non-stop endurance flight when crossing the Sahara Desert-Mediterranean Sea ecological barrier. All birds significantly increased their fuel loads up to 48% of lean body mass and we provide evidence for muscle rebuilding during stopover as flight muscle mass increased by 10%, highlighting the fact that stopover sites can play a major role in the physiological recovery of migrants.

Understanding the molecular mechanism of arsenic and ammonia toxicity and high-temperature stress in Pangasianodon hypophthalmus

The current investigation explores the mechanisms of ammonia and arsenic toxicity, along with high-temperature stress, which other researchers rarely addressed. Pangasianodon hypophthalmus was exposed to low doses of ammonia and arsenic (1/10th of LC50, 2.0 and 2.68 mg L-1, respectively) and high temperature (34 °C) for 105 days. The following treatments were applied: control (unexposed), arsenic (As), ammonia (NH3), ammonia + arsenic (NH3 + As), ammonia + temperature (NH3 + T), and NH3 + As + T. Cortisol levels significantly increased with exposure to ammonia (NH3), arsenic (As), and high temperature (34 °C) compared to the unexposed group. Heat shock protein (HSP 70), inducible nitric oxide synthase (iNOS), and metallothionein (MT) gene expressions were notably upregulated by 122-210%, 98-122%, and 64-238%, respectively, compared to the control. Neurotransmitter enzymes (acetylcholine esterase, AChE) were significantly inhibited by NH3 + As + T, followed by other stressor groups. The apoptotic (caspase, Cas 3a and 3b) and detoxifying (cytochrome P450, CYP P450) pathways were substantially affected by the NH3 + As + T group. Immune (total immunoglobulin, Ig; tumor necrosis factor TNFα; and interleukin IL) and growth-related genes (growth hormone, GH; growth hormone regulator, GHR1 and GHRβ; myostatin, MYST and somatostatin, SMT) were noticeably upregulated by NH3 + As + T, followed by other stress groups, compared to the control group. Weight gain %, protein efficiency ratio, feed efficiency ratio, specific growth rate, and other growth attributes were significantly affected by low doses of ammonia, arsenic, and high-temperature stress. Albumin, total protein, globulin, A:G ratio, and myeloperoxidase (MPO) were highly affected by the As + NH3 + T group. Blood profiling, including red blood cells (RBC), white blood count (WBC), and hemoglobin (Hb), were also impacted by stressor groups compared to the control group. Genotoxicity, as DNA damage, was significantly higher in groups exposed to NH3 + As + T (89%), NH3 + T (78%), NH3 (73), NH3 + As (71), and As (68%). The bioaccumulation of arsenic was substantially higher in liver and kidney tissues. The present study contributes to understanding the toxicity mechanisms of ammonia and arsenic, as well as high-temperature stress, through different gene expressions, biochemical attributes, genotoxicity, immunological status, and growth performance of P. hypophthalmus.

Expansion of the HSP70 gene family in Tegillarca granosa and expression profiles in response to zinc toxicity

Zinc (Zn) is an essential micronutrient in organisms and an abundant element in the Earth's crust. Trace amounts of Zn released from natural sources can enter aquatic ecosystems through weathering and erosion. Zn accumulates in organisms, and when its intracellular concentration exceeds a certain level, it can induce oxidative stress and trigger oxidative stress-mediated heat shock protein (HSP) modulation. HSP70 is the most evolutionarily conserved among the HSP families. Despite extensive research on HSP70 genes in bivalves, the HSP70 gene family of Tegillarca granosa is still poorly characterized. We identified 65 HSP70 genes belonging to 6 families in the T. granosa genome, with 50 HSPa12 and 11 HSPa B2 genes highly expanded. On chromosome 11, 39 HSP70 (60%) genes were identified, and the HSPa12A genes were highly duplicated. A total of 527 and 538 differentially expressed genes were identified in the gills and mantle based on Zn exposure, respectively. The Gene Ontology of cellular anatomical entities was significantly enriched with upregulated differentially expressed genes in the gills and mantle. Eight of the 11 HSPa B2 genes were upregulated in both tissues. Most of the genes identified in both tissues were involved in "protein homeostasis" and "inhibition of apoptosis," which are associated with the HSP70 family's resistance to extrinsic and intrinsic stress. Hence, this study identified that the HSP70 gene family plays a vital role in the adaptation of aquatic organisms to heavy metal (e.g., Zn) stress in contaminated environments by compiling the different physiological responses to preserve homeostasis.

A simulated natural heatwave perturbs bumblebee immunity and resistance to infection

As a consequence of ongoing climate change, heatwaves are predicted to increase in frequency, intensity, and duration in many regions. Such extreme events can shift organisms from thermal optima for physiology and behaviour, with the thermal stress hypothesis predicting reduced performance at temperatures where the maintenance of biological functions is energetically costly. Performance includes the ability to resist biotic stressors, including infectious diseases, with increased exposure to extreme temperatures having the potential to synergise with parasite infection. Climate change is a proposed threat to native bee pollinators, directly and through indirect effects on floral resources, but the thermal stress hypothesis, particularly pertaining to infectious disease resistance, has received limited attention. We exposed adult Bombus impatiens bumblebee workers to simulated, ecologically relevant heatwave or control thermal regimes and assessed longevity, immunity, and resistance to concurrent or future parasite infections. We demonstrate that survival and induced antibacterial immunity are reduced following heatwaves. Supporting that heatwave exposure compromised immunity, the cost of immune activation was thermal regime dependent, with survival costs in control but not heatwave exposed bees. However, in the face of real infections, an inability to mount an optimal immune response will be detrimental, which was reflected by increased trypanosomatid parasite infections following heatwave exposure. These results demonstrate interactions between heatwave exposure and bumblebee performance, including immune and infection outcomes. Thus, the health of bumblebee pollinator populations may be affected through altered interactions with parasites and pathogens, in addition to other effects of extreme manifestations of climate change.

Molecular and functional characterization of heat-shock protein 70 in Aphis gossypii under thermal and xenobiotic stresses

Aphis gossypii, a globally distributed and economically significant pest of several crops, is known to infest a wide range of host plants. Heat shock proteins (Hsps), acting as molecular chaperones, are essential for the insect's environmental stress responses. The present study investigated the molecular characteristics and expression patterns of AgHsp70, a heat shock protein gene, in Aphis gossypii. Our phylogenetic analysis revealed that AgHsp70 shared high similarity with homologs from other insects, suggesting a conserved function across species. The developmental expression profiles of AgHsp70 in A. gossypii showed that the highest transcript levels were observed in the fourth instar nymphs, while the lowest levels were detected in the third instar nymphs. Heat stress and exposure to four different xenobiotics (2-tridecanone, tannic acid, gossypol, and flupyradifurone (4-[(2,2-difluoroethyl)amino]-2(5H)-furanone)) significantly up-regulated AgHsp70 expression. Knockdown of AgHsp70 using RNAi obviously increased the susceptibility of cotton aphids to 2-tridecanone, gossypol and flupyradifurone. Dual-luciferase reporter assays revealed that gossypol and flupyradifurone significantly enhanced the promoter activity of AgHsp70 at a concentration of 10 mg/L. Furthermore, we identified the transcription factor heat shock factor (HSF) as a regulator of AgHsp70, as silencing AgHSF reduced AgHsp70 expression. Our results shed light on the role of AgHsp70 in xenobiotic adaptation and thermo-tolerance.

Control Effects of Short-Term Heatwaves on a Holocyclic Aphid

The soybean aphid, A. glycines, is an important soybean pest. Harbin, in the Heilongjiang Province, is an area with increasing temperatures in China that faces frequent short-term heatwaves. In this study, the development, reproduction, and morph differentiation of A. glycines have been studied when they were exposed to diurnal at 35 °C for seven days, beginning at different developmental stages. The nymph stage duration of A. glycines was longer, the adult lifespans and total lifespans were shorter, and their bodies were smaller when exposed to a diurnal of 35 °C beginning at the 1st to 4th stadium. The adult reproduction period was shorter, and the adult fecundity and intrinsic rate of increase were smaller than those of aphids reared at a diurnal of 25 °C. A higher and lower proportion of gynoparae and males were deposited as offspring on day 13 by adults when exposed to diurnal at 35 °C, beginning at the 1st to 4th stadium, respectively, than those of aphids reared at a constant of 20 °C. These results are important for predicting the dynamics of A. glycines in Harbin soybeans. This provides evidence that short-term heatwaves are probably useful for controlling A. glycines, by inhibiting development and male morphogenesis.