Pub Date : 2025-09-01Epub Date: 2025-06-25DOI: 10.1016/j.cbpa.2025.111899
Xiao-hong Li, Cheng Fu, Xue-ting Tan, Shi-jian Fu
Anxiety, as a crucial stress response to potential threats in animals, exhibits significant individual differences, with high-anxiety individuals typically allocating greater attentional resources to threat detection. We hypothesized that such individuals would demonstrate enhanced threat sensitivity and anti-predator responses, but compromised stress tolerance due to constrained energy allocation. Using the novel tank diving test, we screened zebrafish (Danio rerio) with high- and low-anxiety phenotypes and compared their anti-predator responses (anxiety-like behaviors, metabolic rates, and predator avoidance behaviors) under predator chemical or visual cues, along with their thermal and hypoxia tolerance capacities under baseline conditions. The results demonstrate that high-anxiety zebrafish exhibit enhanced anti-predator responses in threatening environments, while showing no compromised stress tolerance at baseline. These findings demonstrate the adaptive superiority of the high-anxiety phenotype in high-predation-risk environments, providing theoretical foundations for understanding the evolutionary role of anxiety in fish.
{"title":"The effects of individual differences in anxiety on anti-predator responses, thermal and hypoxia tolerance in zebrafish (Danio rerio)","authors":"Xiao-hong Li, Cheng Fu, Xue-ting Tan, Shi-jian Fu","doi":"10.1016/j.cbpa.2025.111899","DOIUrl":"10.1016/j.cbpa.2025.111899","url":null,"abstract":"<div><div>Anxiety, as a crucial stress response to potential threats in animals, exhibits significant individual differences, with high-anxiety individuals typically allocating greater attentional resources to threat detection. We hypothesized that such individuals would demonstrate enhanced threat sensitivity and anti-predator responses, but compromised stress tolerance due to constrained energy allocation. Using the novel tank diving test, we screened zebrafish (<em>Danio rerio</em>) with high- and low-anxiety phenotypes and compared their anti-predator responses (anxiety-like behaviors, metabolic rates, and predator avoidance behaviors) under predator chemical or visual cues, along with their thermal and hypoxia tolerance capacities under baseline conditions. The results demonstrate that high-anxiety zebrafish exhibit enhanced anti-predator responses in threatening environments, while showing no compromised stress tolerance at baseline. These findings demonstrate the adaptive superiority of the high-anxiety phenotype in high-predation-risk environments, providing theoretical foundations for understanding the evolutionary role of anxiety in fish.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"307 ","pages":"Article 111899"},"PeriodicalIF":2.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144512792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Adult male striped hamsters (Cricetulus barabensis) were fed an HFD for 12 weeks to examine individual differences in response to chronic exposure to a high-fat diet (HFD). The hamsters were subsequently assigned to three experimental groups according to those that exhibited body weight gain (GW), a stable body weight (SW), or body weight loss (LW). The GW group showed a profile of HFD-induced obesity, with the highest levels of energy intake, fat content, brown adipose tissue (BAT) mass, UCP1 gene expression in the BAT, and lipid metabolism. The SW group was resistant to HFD, showing lower levels of the above-mentioned markers than those of the GW group. In addition, the LW group appeared to be aversive to HFD, displaying a negative body mass gain compared to the other two groups. Group differences in the relative abundance of several strains of the gut microbiota were also observed, suggesting the potential involvement of the gut microbiota in individual variation in the sensitivity, resistance, and aversive responses to HFD-induced obesity. These data demonstrate the utility of the striped hamster model in functional studies of the mechanisms underlying HFD-induced obesity and its potential treatment and prevention.
{"title":"Individual differences in response to a chronic high-fat diet in striped hamsters (Cricetulus barabensis)","authors":"Wenting Li , Binxin Yin , Xinyuan Dong , Boyang Ding , Jing Wen","doi":"10.1016/j.cbpa.2025.111896","DOIUrl":"10.1016/j.cbpa.2025.111896","url":null,"abstract":"<div><div>Adult male striped hamsters (<em>Cricetulus barabensis</em>) were fed an HFD for 12 weeks to examine individual differences in response to chronic exposure to a high-fat diet (HFD). The hamsters were subsequently assigned to three experimental groups according to those that exhibited body weight gain (GW), a stable body weight (SW), or body weight loss (LW). The GW group showed a profile of HFD-induced obesity, with the highest levels of energy intake, fat content, brown adipose tissue (BAT) mass, <em>UCP1</em> gene expression in the BAT, and lipid metabolism. The SW group was resistant to HFD, showing lower levels of the above-mentioned markers than those of the GW group. In addition, the LW group appeared to be aversive to HFD, displaying a negative body mass gain compared to the other two groups. Group differences in the relative abundance of several strains of the gut microbiota were also observed, suggesting the potential involvement of the gut microbiota in individual variation in the sensitivity, resistance, and aversive responses to HFD-induced obesity. These data demonstrate the utility of the striped hamster model in functional studies of the mechanisms underlying HFD-induced obesity and its potential treatment and prevention.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"307 ","pages":"Article 111896"},"PeriodicalIF":2.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144364755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The caudal neurosecretory system (CNSS) is a neuroendocrine complex unique to fish, first described in 1955. Since then, it has been hypothesized to contribute to several physiological processes, but its real functions remain largely unclear. However, so far, the many studies devoted to it agree that it could play an important role in osmoregulation. More recently, it has also been suggested that it could be involved in thermal adaptation. The zebrafish (Danio rerio) is a well-established model organism for functional studies. Yet so far, the functions of the CNSS have not been thoroughly investigated in this species. As a first step in such investigations, the present study aimed to identify environmental factors whose variations induce changes in CNSS endocrine activity. For this purpose, juvenile zebrafish were submitted to acute (2, 8, and 24 h) pH, salinity, and temperature challenges. As indicators of the CNSS endocrine activity, the expression levels of peptide hormone-encoding genes known or suspected to be synthesized in the CNSS were measured using quantitative PCR. The genes selected for this study were as follows: corticotropin-releasing hormone b (crhb), oxytocin (oxt), proenkephalin (penka and penkb), parathyroid hormone-like hormone (pthlha and pthlhb), stanniocalcin 2 (stc2a and stc2b), urotensin 1 (uts1) and urotensin 2 (uts2a and uts2b). Our findings revealed that the pH challenge affected the expression of three genes – crhb, penka, and stc2b - and the salinity challenge altered four genes - oxt, uts1, uts2a, and uts2b - while the temperature challenge modified the expression of all genes of our panel. These results indicated that the zebrafish CNSS is sensitive to changes in these environmental parameters and support the use of the zebrafish as a relevant model for studying the functions of the CNSS.
{"title":"Impact of acute environmental challenges on the expression of peptide hormone-encoding genes in the zebrafish caudal neurosecretory system","authors":"Bérénice Bichon, Gladys Alfama, Anne-Laure Gaillard, Hervé Tostivint, Guillaume Pézeron","doi":"10.1016/j.cbpa.2025.111893","DOIUrl":"10.1016/j.cbpa.2025.111893","url":null,"abstract":"<div><div>The caudal neurosecretory system (CNSS) is a neuroendocrine complex unique to fish, first described in 1955. Since then, it has been hypothesized to contribute to several physiological processes, but its real functions remain largely unclear. However, so far, the many studies devoted to it agree that it could play an important role in osmoregulation. More recently, it has also been suggested that it could be involved in thermal adaptation. The zebrafish (<em>Danio rerio</em>) is a well-established model organism for functional studies. Yet so far, the functions of the CNSS have not been thoroughly investigated in this species. As a first step in such investigations, the present study aimed to identify environmental factors whose variations induce changes in CNSS endocrine activity. For this purpose, juvenile zebrafish were submitted to acute (2, 8, and 24 h) pH, salinity, and temperature challenges. As indicators of the CNSS endocrine activity, the expression levels of peptide hormone-encoding genes known or suspected to be synthesized in the CNSS were measured using quantitative PCR. The genes selected for this study were as follows: <em>corticotropin-releasing hormone b</em> (<em>crhb</em>), oxytocin (<em>oxt</em>), <em>proenkephalin</em> (<em>penka</em> and <em>penkb</em>), <em>parathyroid hormone-like hormone</em> (<em>pthlha</em> and <em>pthlhb</em>), <em>stanniocalcin 2</em> (<em>stc2a</em> and <em>stc2b</em>), <em>urotensin 1</em> (<em>uts1</em>) and <em>urotensin 2</em> (<em>uts2a</em> and <em>uts2b</em>). Our findings revealed that the pH challenge affected the expression of three genes – <em>crhb</em>, <em>penka,</em> and <em>stc2b -</em> and the salinity challenge altered four genes - <em>oxt, uts1, uts2a</em>, and <em>uts2b</em> - while the temperature challenge modified the expression of all genes of our panel. These results indicated that the zebrafish CNSS is sensitive to changes in these environmental parameters and support the use of the zebrafish as a relevant model for studying the functions of the CNSS.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"307 ","pages":"Article 111893"},"PeriodicalIF":2.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144295407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Insulin-like growth factor binding proteins (IGFBPs) are key regulators of insulin-like growth factors (IGFs), which play essential roles in growth and development. In this study, a IGFBP related protein cDNA from Macrobrachium rosenbergii (designated Mr-IGFBP-rP) was identified. The full-length cDNA of Mr-IGFBP-rP is 1494 base pairs (bp) including a 22 bp 5′-untranslated region (UTR), a 707 bp 3’-UTR, and a 765 bp open reading frame (ORF) encoding a 254-amino acid protein. The Mr-IGFBP-rP protein contains three conserved domains: an IGF-binding domain (amino acids 34–89), a Kazal-type serine protease inhibitor domain (102–125), and an immunoglobulin-like C2-type domain (147–245). Sequence analysis revealed that Mr-IGFBP-rP shares 75.74 % identity with the IGFBP-rP1 of Palaemon carinicauda and 63.26 % with that of Penaeus chinensis. Expression analysis showed that Mr-IGFBP-rP is most highly expressed in the abdominal ganglia, followed by gill, heart, and brain. Eleven single nucleotide polymorphisms (SNPs) were identified within Mr-IGFBP-rP. Of these, three SNPs showed significant associations with growth traits in M. rosenbergii. Specifically, individuals with the AA genotype at the 5263-G/A locus exhibited greater body weight. Those with the TT genotype at the 5302-G/T locus showed increased body weight, cephalothorax height, and abdominal segment 1 height. In contrast, the CC genotype at the 5743-G/C locus was associated with reduced cephalothorax length, cephalothorax height, abdominal segment 1 height, and abdominal length. This study lays a foundation for understanding the role of Mr-IGFBP-rP in growth regulation in M. rosenbergii. The identified SNPs hold potential as candidate markers for marker-assisted selection in this species.
{"title":"Characterization of the IGFBP-rP cDNA and its associations with growth traits in Macrobrachium rosenbergii","authors":"Qianqian Ding, Yifan He, Weifeng Gao, Xiaojian Gao, Yao Zhang, Xiaojun Zhang, Qun Jiang","doi":"10.1016/j.cbpa.2025.111901","DOIUrl":"10.1016/j.cbpa.2025.111901","url":null,"abstract":"<div><div>Insulin-like growth factor binding proteins (IGFBPs) are key regulators of insulin-like growth factors (IGFs), which play essential roles in growth and development. In this study, a IGFBP related protein cDNA from <em>Macrobrachium rosenbergii</em> (designated <em>Mr-IGFBP-rP</em>) was identified. The full-length cDNA of <em>Mr-IGFBP-rP</em> is 1494 base pairs (bp) including a 22 bp 5′-untranslated region (UTR), a 707 bp 3’-UTR, and a 765 bp open reading frame (ORF) encoding a 254-amino acid protein. The Mr-IGFBP-rP protein contains three conserved domains: an IGF-binding domain (amino acids 34–89), a Kazal-type serine protease inhibitor domain (102–125), and an immunoglobulin-like C2-type domain (147–245). Sequence analysis revealed that Mr-IGFBP-rP shares 75.74 % identity with the IGFBP-rP1 of <em>Palaemon carinicauda</em> and 63.26 % with that of <em>Penaeus chinensis</em>. Expression analysis showed that <em>Mr-IGFBP-rP</em> is most highly expressed in the abdominal ganglia, followed by gill, heart, and brain. Eleven single nucleotide polymorphisms (SNPs) were identified within <em>Mr-IGFBP-rP</em>. Of these, three SNPs showed significant associations with growth traits in <em>M. rosenbergii</em>. Specifically, individuals with the AA genotype at the 5263-G/A locus exhibited greater body weight. Those with the TT genotype at the 5302-G/T locus showed increased body weight, cephalothorax height, and abdominal segment 1 height. In contrast, the CC genotype at the 5743-G/C locus was associated with reduced cephalothorax length, cephalothorax height, abdominal segment 1 height, and abdominal length. This study lays a foundation for understanding the role of <em>Mr-IGFBP-rP</em> in growth regulation in <em>M. rosenbergii</em>. The identified SNPs hold potential as candidate markers for marker-assisted selection in this species.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"307 ","pages":"Article 111901"},"PeriodicalIF":2.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144523509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-01Epub Date: 2025-05-31DOI: 10.1016/j.cbpa.2025.111883
Nguyen Van Thao , Jaime McAllister , Andrea C. Alfaro , Nha T. Ngo , Craig Mundy
Transport stress significantly influences the well-being and survival of abalone, yet the underlying metabolic changes and physiological responses associated with this stress remain poorly understood. To gain comprehensive insights into the metabolic changes and physiological responses of abalone (Haliotis rubra) under transport stress, we conducted a targeted liquid chromatography–mass spectrometry (LC–MS) metabolomics investigation on haemolymph and gill samples collected at different time points, including post-harvesting (pre-transport), post-transport and post-immersion (water holding period) and post-live exporting transport. The results revealed 143 and 141 metabolites that were significantly different among sampling times in haemolymph and gill, respectively. Notably, most of the metabolite differences occurred between the post-transport and post-immersion times, which indicate the strong impacts of transport stress on abalone metabolism. Interestingly, certain metabolites, such as lactic acid, succinic acid, L-hydroxyglutaric acid, uric acid, and myo-inositol, showed time-dependent increases during transport, suggesting their potential as stress biomarkers in abalone. Moreover, abalone that were acclimatized in holding tanks exhibited lesser metabolic changes compared to non-acclimatized, despite both groups being transported with oxygen supply. This highlights the significance of acclimatization and oxygen supply in reducing stress for abalone during transport. Enrichment analysis on abalone samples at 24 h post-transport compared to 96 h post-immersion identified 12 significantly impacted pathways in haemolymph and 34 pathways in gill tissues, indicating a range of metabolic disturbances in transported abalone, such as energy-related pathways, amino acid metabolisms, carbohydrate metabolisms, vitamin metabolisms, oxidative stress, and others. These results offer valuable insights into the physiological responses of abalone to transport stress, guiding improved transport practices to ensure good quality of products arriving at their market destinations.
{"title":"Metabolic changes associated with live transport stress of Haliotis rubra abalone","authors":"Nguyen Van Thao , Jaime McAllister , Andrea C. Alfaro , Nha T. Ngo , Craig Mundy","doi":"10.1016/j.cbpa.2025.111883","DOIUrl":"10.1016/j.cbpa.2025.111883","url":null,"abstract":"<div><div>Transport stress significantly influences the well-being and survival of abalone, yet the underlying metabolic changes and physiological responses associated with this stress remain poorly understood. To gain comprehensive insights into the metabolic changes and physiological responses of abalone (<em>Haliotis rubra</em>) under transport stress, we conducted a targeted liquid chromatography–mass spectrometry (LC–MS) metabolomics investigation on haemolymph and gill samples collected at different time points, including post-harvesting (pre-transport), post-transport and post-immersion (water holding period) and post-live exporting transport. The results revealed 143 and 141 metabolites that were significantly different among sampling times in haemolymph and gill, respectively. Notably, most of the metabolite differences occurred between the post-transport and post-immersion times, which indicate the strong impacts of transport stress on abalone metabolism. Interestingly, certain metabolites, such as lactic acid, succinic acid, L-hydroxyglutaric acid, uric acid, and myo-inositol, showed time-dependent increases during transport, suggesting their potential as stress biomarkers in abalone. Moreover, abalone that were acclimatized in holding tanks exhibited lesser metabolic changes compared to non-acclimatized, despite both groups being transported with oxygen supply. This highlights the significance of acclimatization and oxygen supply in reducing stress for abalone during transport. Enrichment analysis on abalone samples at 24 h post-transport compared to 96 h post-immersion identified 12 significantly impacted pathways in haemolymph and 34 pathways in gill tissues, indicating a range of metabolic disturbances in transported abalone, such as energy-related pathways, amino acid metabolisms, carbohydrate metabolisms, vitamin metabolisms, oxidative stress, and others. These results offer valuable insights into the physiological responses of abalone to transport stress, guiding improved transport practices to ensure good quality of products arriving at their market destinations.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"307 ","pages":"Article 111883"},"PeriodicalIF":2.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144210317","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-01Epub Date: 2025-06-07DOI: 10.1016/j.cbpa.2025.111892
Peter D. Dijkstra
Attaining large body size has several selective benefits, however, increased growth rate has potential costs that can constrain investment in other life history traits, such as reproductive output and territorial defense. Oxidative stress can both constrain and result from growth, potentially mediating life history trade-offs between growth rate and other life history traits. Studies on the oxidative cost of growth have provided mixed evidence, in part because components of oxidative balance, including oxidative damage and antioxidant function, is influenced by investment in other activities in a tissue-specific manner. Here, I examined how among-individual variation in growth rate is linked to oxidative stress, and how this relationship is influenced by markers of social dominance (aggressiveness and relative gonad size) in males of the cichlid fish Astatotilapa burtoni. To this end, 7 markers of oxidative damage and antioxidant function in various tissue types (total of 14 measurements) were assessed in dominant and subordinate males. I found that dominant males grew faster than subordinate males. However, increased growth was linked to reduced oxidative stress. This effect was independent of social status but modulated by the degree of social dominance. Overall, the results are consistent with oxidative stress mediating the link between growth and other life history traits. However, my findings challenge the idea that increased growth rate results in elevated oxidative stress, perhaps due to effective protective mechanisms that can neutralize the oxidative challenge of growth.
{"title":"Growth rate is associated with reduced oxidative stress and this effect is modulated by the degree of social dominance in males of an African cichlid fish","authors":"Peter D. Dijkstra","doi":"10.1016/j.cbpa.2025.111892","DOIUrl":"10.1016/j.cbpa.2025.111892","url":null,"abstract":"<div><div>Attaining large body size has several selective benefits, however, increased growth rate has potential costs that can constrain investment in other life history traits, such as reproductive output and territorial defense. Oxidative stress can both constrain and result from growth, potentially mediating life history trade-offs between growth rate and other life history traits. Studies on the oxidative cost of growth have provided mixed evidence, in part because components of oxidative balance, including oxidative damage and antioxidant function, is influenced by investment in other activities in a tissue-specific manner. Here, I examined how among-individual variation in growth rate is linked to oxidative stress, and how this relationship is influenced by markers of social dominance (aggressiveness and relative gonad size) in males of the cichlid fish <em>Astatotilapa burtoni</em>. To this end, 7 markers of oxidative damage and antioxidant function in various tissue types (total of 14 measurements) were assessed in dominant and subordinate males. I found that dominant males grew faster than subordinate males. However, increased growth was linked to reduced oxidative stress. This effect was independent of social status but modulated by the degree of social dominance. Overall, the results are consistent with oxidative stress mediating the link between growth and other life history traits. However, my findings challenge the idea that increased growth rate results in elevated oxidative stress, perhaps due to effective protective mechanisms that can neutralize the oxidative challenge of growth.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"307 ","pages":"Article 111892"},"PeriodicalIF":2.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144259425","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-01Epub Date: 2025-06-02DOI: 10.1016/j.cbpa.2025.111884
Shi-Hong Gu
Activation of extracellular signal-regulated kinase (ERK) signaling is related to chilling-induced diapause termination in Bombyx mori eggs. However, the changes in expressions of upstream signaling and downstream target genes are not very clear. In the present study, I investigated temporal changes in gene expressions of the prothoracicotropic hormone (PTTH) and epidermal growth factor (Egf) signaling pathways, which are the major stimulators of ERK signaling in insect systems, during a long chilling period. My results showed that when chilling was conducted from 2 days post-oviposition, expressions of PTTH/Egf signaling pathway genes were maintained at relatively higher levels, compared to those kept at 25 °C. In eggs exposed to 5 °C from 15 days post-oviposition, expression of the PTTH gene had dramatically increased by day 45 after chilling. Egf signaling pathway genes, including spitz (spi), vein (vn), rhomboid (rho), and Egf receptor (Egfr), showed gene-specific increasing patterns during the chilling period. I further showed that expression of the pointed (an ERK target) gene was maintained at a relatively higher when chilling was conducted from 2 days post-oviposition. Expression of the pointed gene had dramatically increased by day 45 in eggs chilled beginning after 15 days post-oviposition. Additionally, dechorionation increased pointed gene expression. LY294002 (a specific phosphatidylinositol 3-kinase (PI3K) inhibitor) and U0126 (an ERK inhibitor) inhibited pointed gene expression in dechorionated eggs, indicating that both PI3K and ERK are involved in increased pointed gene expression. When eggs that had been kept at 5 °C for 30 days were transferred to 25 °C, expression levels of PTTH and pointed genes decreased after transfer, clearly indicating that continuous chilling for 45 days is necessary to sustain the higher expressions of these genes. To the best of my knowledge, this study presents the first comprehensive analysis of the transcriptional regulation of both upstream and downstream genes in the ERK signaling pathway during a chilling period, offering valuable insights into the mechanisms underlying chilling-induced diapause termination.
{"title":"Temporal changes in PTTH/Egf signaling and ERK target gene expressions during chilling-induced diapause termination in Bombyx mori eggs","authors":"Shi-Hong Gu","doi":"10.1016/j.cbpa.2025.111884","DOIUrl":"10.1016/j.cbpa.2025.111884","url":null,"abstract":"<div><div>Activation of extracellular signal-regulated kinase (ERK) signaling is related to chilling-induced diapause termination in <em>Bombyx mori</em> eggs. However, the changes in expressions of upstream signaling and downstream target genes are not very clear. In the present study, I investigated temporal changes in gene expressions of the prothoracicotropic hormone (PTTH) and epidermal growth factor (Egf) signaling pathways, which are the major stimulators of ERK signaling in insect systems, during a long chilling period. My results showed that when chilling was conducted from 2 days post-oviposition, expressions of PTTH/Egf signaling pathway genes were maintained at relatively higher levels, compared to those kept at 25 °C. In eggs exposed to 5 °C from 15 days post-oviposition, expression of the <em>PTTH</em> gene had dramatically increased by day 45 after chilling. Egf signaling pathway genes, including <em>spitz</em> (<em>spi</em>), <em>vein</em> (<em>vn</em>), <em>rhomboid</em> (<em>rho</em>), and <em>Egf receptor</em> (<em>Egfr</em>), showed gene-specific increasing patterns during the chilling period. I further showed that expression of the <em>pointed</em> (an ERK target) gene was maintained at a relatively higher when chilling was conducted from 2 days post-oviposition. Expression of the <em>pointed</em> gene had dramatically increased by day 45 in eggs chilled beginning after 15 days post-oviposition. Additionally, dechorionation increased <em>pointed</em> gene expression. LY294002 (a specific phosphatidylinositol 3-kinase (PI3K) inhibitor) and U0126 (an ERK inhibitor) inhibited <em>pointed</em> gene expression in dechorionated eggs, indicating that both PI3K and ERK are involved in increased <em>pointed</em> gene expression. When eggs that had been kept at 5 °C for 30 days were transferred to 25 °C, expression levels of <em>PTTH</em> and <em>pointed</em> genes decreased after transfer, clearly indicating that continuous chilling for 45 days is necessary to sustain the higher expressions of these genes. To the best of my knowledge, this study presents the first comprehensive analysis of the transcriptional regulation of both upstream and downstream genes in the ERK signaling pathway during a chilling period, offering valuable insights into the mechanisms underlying chilling-induced diapause termination.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"307 ","pages":"Article 111884"},"PeriodicalIF":2.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144213265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-01Epub Date: 2025-07-03DOI: 10.1016/j.cbpa.2025.111902
Subu Yatung, Amit Kumar Trivedi
Anthropogenic factors, particularly urbanization, have immense implications for the natural light-dark cycle of the species. The present study deliberates on the effects of dim light at night on the transcript expression of reproductive, steroidogenic, and metabolic gene markers in adult male tree sparrows (Passer montanus). Adult male birds were procured locally and were divided into two groups (n = 6 birds/group). Both groups were exposed to 12 h of light and 12 h of darkness, but group two (dLAN group) with a constant dim light (10 lx) during the dark hours. The experiment was run for 2 weeks. After that, birds were sampled, and the hypothalamus, liver, and gonads were harvested and used for gene expression analysis. Blood plasma was used for hormonal and biochemical assays. The findings suggest that 2 weeks of exposure did not significantly change the body mass, cholesterol, glucose, and testosterone assay. However, an increase in testicular volume was observed in dLAN-treated birds. Furthermore, elevation in hypothalamic transcripts (Tshβ, Dio2, GnRH, and Eya3) involved in the seasonal reproduction, along with an increase in steroidogenic transcripts (StAr, Scp2, Srd5a1, Hsd11b2, and Er) in the testis was observed; besides, liver metabolic transcript levels (Acaca, Fasn, Hmcg, Idh2, Sdhaf4, Sdhaf2, Sdhc, Fh, Mdh, Foxo1, and Vip) were also elevated in the dLAN-treated group compared to the control group. Overall, the study shows that even a short-term exposure to the lower intensity of dim light at night of 2 weeks of duration can stimulate the hypothalamic gonadal axis and liver metabolism in tree sparrows. These results could play a role in understanding the effect of light at night on the physiology of diurnal avian species.
{"title":"Short-term exposure to dim light at night affects reproduction and metabolism-linked processes in adult male tree sparrows (Passer montanus)","authors":"Subu Yatung, Amit Kumar Trivedi","doi":"10.1016/j.cbpa.2025.111902","DOIUrl":"10.1016/j.cbpa.2025.111902","url":null,"abstract":"<div><div>Anthropogenic factors, particularly urbanization, have immense implications for the natural light-dark cycle of the species. The present study deliberates on the effects of dim light at night on the transcript expression of reproductive, steroidogenic, and metabolic gene markers in adult male tree sparrows (<em>Passer montanus</em>). Adult male birds were procured locally and were divided into two groups (<em>n</em> = 6 birds/group). Both groups were exposed to 12 h of light and 12 h of darkness, but group two (dLAN group) with a constant dim light (10 lx) during the dark hours. The experiment was run for 2 weeks. After that, birds were sampled, and the hypothalamus, liver, and gonads were harvested and used for gene expression analysis. Blood plasma was used for hormonal and biochemical assays. The findings suggest that 2 weeks of exposure did not significantly change the body mass, cholesterol, glucose, and testosterone assay. However, an increase in testicular volume was observed in dLAN-treated birds. Furthermore, elevation in hypothalamic transcripts (<em>Tshβ</em>, <em>Dio2</em>, <em>GnRH</em>, and <em>Eya3)</em> involved in the seasonal reproduction, along with an increase in steroidogenic transcripts (<em>StAr</em>, <em>Scp2</em>, <em>Srd5a1</em>, <em>Hsd11b2</em>, and <em>Er</em>) in the testis was observed; besides, liver metabolic transcript levels (<em>Acaca</em>, <em>Fasn</em>, <em>Hmcg</em>, <em>Idh2</em>, <em>Sdhaf4</em>, <em>Sdhaf2</em>, <em>Sdhc</em>, <em>Fh</em>, <em>Mdh</em>, <em>Foxo1</em>, and <em>Vip</em>) were also elevated in the dLAN-treated group compared to the control group. Overall, the study shows that even a short-term exposure to the lower intensity of dim light at night of 2 weeks of duration can stimulate the hypothalamic gonadal axis and liver metabolism in tree sparrows. These results could play a role in understanding the effect of light at night on the physiology of diurnal avian species.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"307 ","pages":"Article 111902"},"PeriodicalIF":2.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144549430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-01Epub Date: 2025-05-18DOI: 10.1016/j.cbpa.2025.111880
Fred Tremblay , Emily S. Choy , David A. Fifield , Glenn J. Tattersall , François Vézina , Ryan O'Connor , Oliver P. Love , Grant H. Gilchrist , Kyle H. Elliott
The Arctic is warming at four times the global average rate and most studies have focused on the indirect (e.g., changes in food web) rather than the direct effects of climate change. However, as Arctic animals often have low capacity to dissipate heat, the direct effect of warming could impact them significantly (heat stress). To study heat stress, biophysical models have been used in many species to estimate operative temperature (Te, integrated temperature of the thermal environment experienced by an individual). Here, we developed biophysical models of an Arctic seabird, the thick-billed murre (Uria lomvia). We demonstrated that 3D-printed painted models perform similarly to the more traditionally used feather-covered models. We deployed our models on Coats Island, Nunavut, Canada to study heat stress, which occurs in murres when operative temperature is above 21.2 °C (the temperature at which evaporative water loss (EWL) rates increase to maintain a constant body temperatures). Murre operative temperatures ranged from 5.5 °C to 46.5 °C despite ambient temperatures never exceeding 24.7 °C (range: 3.4–24.7 °C), and murres experienced heat stress on 61 % of the days during the breeding season (range: 24–85 %). Using known equations of EWL as a function of temperature, we estimated that murres lost 3.79 % to 4.61 % of their body mass in water daily. Our study confirms the physiological challenges faced by Arctic seabirds during the breeding season, while also demonstrating the value of biophysical models as non-invasive tools to study the effects of heat stress on seabirds.
{"title":"Dealing with the heat: Assessing heat stress in an Arctic seabird using 3D-printed thermal models","authors":"Fred Tremblay , Emily S. Choy , David A. Fifield , Glenn J. Tattersall , François Vézina , Ryan O'Connor , Oliver P. Love , Grant H. Gilchrist , Kyle H. Elliott","doi":"10.1016/j.cbpa.2025.111880","DOIUrl":"10.1016/j.cbpa.2025.111880","url":null,"abstract":"<div><div>The Arctic is warming at four times the global average rate and most studies have focused on the indirect (e.g., changes in food web) rather than the direct effects of climate change. However, as Arctic animals often have low capacity to dissipate heat, the direct effect of warming could impact them significantly (heat stress). To study heat stress, biophysical models have been used in many species to estimate operative temperature (Te, integrated temperature of the thermal environment experienced by an individual). Here, we developed biophysical models of an Arctic seabird, the thick-billed murre (<em>Uria lomvia</em>). We demonstrated that 3D-printed painted models perform similarly to the more traditionally used feather-covered models. We deployed our models on Coats Island, Nunavut, Canada to study heat stress, which occurs in murres when operative temperature is above 21.2 °C (the temperature at which evaporative water loss (EWL) rates increase to maintain a constant body temperatures). Murre operative temperatures ranged from 5.5 °C to 46.5 °C despite ambient temperatures never exceeding 24.7 °C (range: 3.4–24.7 °C), and murres experienced heat stress on 61 % of the days during the breeding season (range: 24–85 %). Using known equations of EWL as a function of temperature, we estimated that murres lost 3.79 % to 4.61 % of their body mass in water daily. Our study confirms the physiological challenges faced by Arctic seabirds during the breeding season, while also demonstrating the value of biophysical models as non-invasive tools to study the effects of heat stress on seabirds.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"306 ","pages":"Article 111880"},"PeriodicalIF":2.1,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144113110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-01Epub Date: 2025-04-11DOI: 10.1016/j.cbpa.2025.111866
Jorge Eduardo Aedo , Daniela Aravena-Canales , Juan Antonio Valdés , Alfredo Molina
Cortisol, a fundamental slow-acting hormone in teleosts, plays a crucial role in acclimating to changes in saline environments. Cortisol effects are associated with its interaction with intracellular glucocorticoid (GR) and mineralocorticoid (MR) receptors, which subsequently regulate gene expression through the cortisol-receptor complex. This mechanism is known as a genomic cortisol signaling and has been studied extensively. However, recent studies have begun to explore a membrane-initiated cortisol pathway that is initiated on the cellular surface, revealing its critical role in the initial metabolic adjustments during the physiological stress response. Nevertheless, the role of this novel membrane-mediated cortisol action during acclimatization to saline environments remain to be elucidated. To investigate this, an in vivo assay was performed in which juvenile rainbow trout were maintained in freshwater (FW) (0.1 ppt), intraperitoneally injected with vehicle, cortisol or cortisol-BSA (three hours of treatment), and transferred to saline water (15 ppt) for one additional hour. Samples of blood and gills were obtained from each fish in order to measure the plasma cortisol, glucose and chloride concentrations, as well as the expression levels of the gr1, gr2, mr, and key osmoregulatory genes. Membrane-initiated cortisol action increased plasma glucose and chloride levels in fish after one hour of saline transfer in comparison with the vehicle group. Furthermore, cortisol exerts a novel regulatory influence on the expression of gr2, as well as tight junction proteins claudin10e and cldn30 in the gills. In contrast, other osmoregulation-related genes, such as cftr and nkcc1, are exclusively mediated by genomic cortisol signaling. These results suggest that membrane-initiated cortisol action plays a significant role in the rapid acclimation of fish to changes in salinity environments.
{"title":"Participation of membrane-initiated cortisol effects on the rapid acclimation of rainbow trout (Oncorhynchus mykiss) to increased salinity","authors":"Jorge Eduardo Aedo , Daniela Aravena-Canales , Juan Antonio Valdés , Alfredo Molina","doi":"10.1016/j.cbpa.2025.111866","DOIUrl":"10.1016/j.cbpa.2025.111866","url":null,"abstract":"<div><div>Cortisol, a fundamental slow-acting hormone in teleosts, plays a crucial role in acclimating to changes in saline environments. Cortisol effects are associated with its interaction with intracellular glucocorticoid (GR) and mineralocorticoid (MR) receptors, which subsequently regulate gene expression through the cortisol-receptor complex. This mechanism is known as a genomic cortisol signaling and has been studied extensively. However, recent studies have begun to explore a membrane-initiated cortisol pathway that is initiated on the cellular surface, revealing its critical role in the initial metabolic adjustments during the physiological stress response. Nevertheless, the role of this novel membrane-mediated cortisol action during acclimatization to saline environments remain to be elucidated. To investigate this, an <em>in vivo</em> assay was performed in which juvenile rainbow trout were maintained in freshwater (FW) (0.1 ppt), intraperitoneally injected with vehicle, cortisol or cortisol-BSA (three hours of treatment), and transferred to saline water (15 ppt) for one additional hour. Samples of blood and gills were obtained from each fish in order to measure the plasma cortisol, glucose and chloride concentrations, as well as the expression levels of the <em>gr1</em>, <em>gr2</em>, <em>mr</em>, and key osmoregulatory genes. Membrane-initiated cortisol action increased plasma glucose and chloride levels in fish after one hour of saline transfer in comparison with the vehicle group. Furthermore, cortisol exerts a novel regulatory influence on the expression of <em>gr2,</em> as well as tight junction proteins <em>claudin10e</em> and <em>cldn30</em> in the gills. In contrast, other osmoregulation-related genes, such as <em>cftr and nkcc1</em>, are exclusively mediated by genomic cortisol signaling. These results suggest that membrane-initiated cortisol action plays a significant role in the rapid acclimation of fish to changes in salinity environments.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"306 ","pages":"Article 111866"},"PeriodicalIF":2.1,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143887694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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