Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology最新文献

{"title":"The development and plasticity of acid excretion mechanisms in early life stage red drum, Sciaenops ocellatus","authors":"Joshua Lonthair ,&nbsp;Andrew J. Esbaugh","doi":"10.1016/j.cbpa.2025.111910","DOIUrl":"10.1016/j.cbpa.2025.111910","url":null,"abstract":"<div><div>Ocean acidification (OA) has been shown to affect early life stage fishes in a variety of ways, including reduced survival and growth, and increased tissue damage. Yet, there is also substantial interspecies variability in the sensitivity of early life stage fishes to high CO₂, and it has been theorized that this may relate to the ontogeny of systemic acid-base regulatory pathways; an area that has been surprisingly understudied in obligate marine species. Here, we used an integrative set of approaches to describe the development and plasticity of acid excretion pathways in developing red drum (<em>Sciaenops ocellatus</em>), a marine fish native to the Gulf of Mexico. We observed mRNA expression of relevant transporters and ionocytes immediately post-hatch (36 h post-fertilization, hpf) with relatively stable abundance throughout the pre-metamorphic stages. Consistent with work in adults and seawater acclimated euryhaline larvae, we demonstrate strong co-localization of acid excretion proteins within a single epithelial ionocyte cell-type. Measurements of epithelial Δ[H]⁺, an indicator of proton efflux, showed that by 72 hpf larvae had CO₂-responsive EIPA-sensitive acid excretion, confirming the presence of sodium proton exchanger (NHE)-mediated acid excretion. Elevated mRNA expression of <em>nhe2</em> and <em>nhe3</em> was induced following exposure to 5500 and 12,000 μatm CO₂, which coincided with the absence of further survival effects relative to lower dose CO₂. Overall, these data confirm that red drum have fully functional epithelial acid excretion pathways in early life, and that plasticity in these pathways may offer survival benefits.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"308 ","pages":"Article 111910"},"PeriodicalIF":2.2,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144735493","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}

{"title":"Impacts of heat stress and its mitigation by capsaicin in health status and digestive enzymes in house sparrows (Passer domesticus)","authors":"Julia Cacace ,&nbsp;Guido Fernández Marinone ,&nbsp;Fabricio Damián Cid ,&nbsp;Juan Gabriel Chediack","doi":"10.1016/j.cbpa.2025.111909","DOIUrl":"10.1016/j.cbpa.2025.111909","url":null,"abstract":"<div><div>Heatwaves and warm spells occurring worldwide as a result of climate change disrupt the homeostasis of animals, leading to heat stress. Consequently, animals must respond to these alterations in order to ensure their survival. The response involves several physiological changes, such as releasing of glucocorticoids and catecholamines, to restore homeostasis. Due to the lack of knowledge on this subject in wild birds, the objective of the present work was to study the effect of heat stress on body condition and digestive system in house sparrows (<em>Passer domesticus</em>). In addition, since capsaicin is used as additive in poultry to mitigate heat stress and it is a common additive in seeds for house birdfeeders to prevent squirrels from eating their food, the second objective of this study was a possible role of capsaicin as a dietary additive in mitigating heat stress and to check the effect of capsaicin in digestive system. In this work, we measured heterophil/lymphocytes ratio (H/L ratio) as a proxy of stress; body mass, hematocrit, uric acid and digestive enzymes (intestinal and pancreatic) under stress conditions at 32 ± 2 °C and under normal conditions at 22 ± 2 °C. In addition, we evaluated the effect of capsaicin in both situations (heat stress at 32 °C and normal condition 22 °C). We found an increase of H/L ratio under heat stress, and decrease of H/L ratio with capsaicin on animals exposed to heat stress. Although a loss of intestinal mass was observed in animals exposed at 32 °C, digestive enzyme activity does not change under heat stress or under capsaicin administration. Improving knowledge in this field is relevant at the level of animal nutrition and veterinary medicine, while also bearing relevance for wild birds, where it becomes crucial to explore potential mitigation strategies for future global warming scenarios.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"308 ","pages":"Article 111909"},"PeriodicalIF":2.2,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144725137","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}

{"title":"Analysis of visual opsin gene expression in Japanese eels upon sexual maturation and exposure to different wavelengths of light","authors":"Jun-Hwan Byun ,&nbsp;Seung-Ju Oh ,&nbsp;Yeo-Reum Kim ,&nbsp;Chae-Eun Yu ,&nbsp;Jihun Kim ,&nbsp;Hyo-Jeong Kim ,&nbsp;Minjae Kim ,&nbsp;Byeong-Hoon Kim ,&nbsp;Sung-Pyo Hur ,&nbsp;Jong-Myoung Kim","doi":"10.1016/j.cbpa.2025.111908","DOIUrl":"10.1016/j.cbpa.2025.111908","url":null,"abstract":"<div><div>Fish inhabiting diverse photic environments, from the deep sea to shallow freshwater, offer a valuable model for studying visual receptor characteristics and spectral adaptation mechanisms. This study investigated changes in visual opsin transcript levels in Japanese eels (<em>Anguilla japonica</em>) during sexual development and exposure to light conditions simulating their life cycle. Tissue-specific expression analysis revealed the predominance of four opsin genes (<em>dso</em>, <em>fwo</em>, <em>rh2</em>, and <em>sws2</em>) in the eyes. Sexual maturation using human chorionic gonadotropin was confirmed by increased gonadosomatic index values and histological changes in the testis. Upon confirming dynamic day/night shifts in the retinal pigment epithelium layer, the effects of sexual maturation and light on opsin gene expression were analyzed via exposure to light-emitting diodes of different wavelengths. Immature eels showed increased <em>sws2</em> expression under blue and green light during the day, with dominant <em>dso</em>, <em>fwo</em>, <em>rh2</em>, and <em>sws2</em> expression in darkness and green light during the night. Conversely, mature eels showed elevated expression levels of <em>dso</em> and <em>rh2</em> under white light and dark conditions, implicating their broad-spectrum and blue-shifted adaptation to deep-sea migration. Notably, cortisol levels in sexually mature eels were significantly lower under dark conditions, underscoring the ecological significance of low light during reproductive migration. Overall, these findings highlight the developmental plasticity of opsin expression and stress responses driven by ecological requirements and life cycle changes, enhancing our understanding of visual and physiological adaptations in migratory fish and providing insights into the evolutionary mechanisms shaping aquatic sensory systems.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"308 ","pages":"Article 111908"},"PeriodicalIF":2.2,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144720915","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}

{"title":"Corrigendum to “Melatonin modulates autophagy, mitochondria and antioxidant in the liver and brain of Perccottus glenni during recovery from freezing” [Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 303, 2025, 111824].","authors":"Cunrun Ye,&nbsp;Zhaoyang Ning,&nbsp;Tingting Hu,&nbsp;Xiaoyu Zhao,&nbsp;Weijie Mu","doi":"10.1016/j.cbpa.2025.111894","DOIUrl":"10.1016/j.cbpa.2025.111894","url":null,"abstract":"","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"307 ","pages":"Article 111894"},"PeriodicalIF":2.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144280483","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}

{"title":"Water pH alters acid-base compensatory responses in white sturgeon (Acipenser transmontanus) exposed to modest and severe environmental hypercapnia","authors":"Ryan B. Shartau ,&nbsp;Daniel W. Baker","doi":"10.1016/j.cbpa.2025.111900","DOIUrl":"10.1016/j.cbpa.2025.111900","url":null,"abstract":"<div><div>Elevated CO₂ (hypercapnia) in fishes induces a respiratory acidosis, which is compensated by branchial acid-base relevant ion transfer. This organismal compensation is hypothesized to be affected by water pH, but assessing this effect is difficult when examining fish species (e.g., rainbow trout <em>Oncorhynchus mykiss</em>, Japanese flounder, <em>Paralichthys olivaceus</em>) that rely on extracellular pH regulation (pHe) to drive recovery as when it fails, mortality may occur quickly. Examining fishes that both perform pHe compensation, but do not require it for survival due to preferential intracellular pH (pH_i) regulation (PPR) such as does the white sturgeon (<em>Acipenser transmontanus</em>), allows us to determine the effect of water pH on acid-base compensation during hypercapnia. White sturgeon were exposed to 48 h of elevated CO₂ tensions while manipulating water pH to determine how water pH can alter patterns of acid-base compensation. Our findings demonstrate that water pH manipulation can have significant effects on the pHe compensatory response. For example, complete pHe compensation was observed in fish exposed to water equilibrated with 1 kPa CO₂, but reducing water pH by ∼1 pH unit prevented complete compensation. Alternately, when sturgeon were exposed to alkalized water equilibrated with 4 kPa CO₂ (i.e., pH of 6.3 compared to 5.7 for water with 4 kPa CO₂), pH compensation was more rapid. Water pH and pHe compensation rates had no effect on pH_i regulation. Our findings demonstrate that water pH can aid or assist pHe compensatory rates at a range of hypercapnic challenges, and so may have contributed to the origin of PPR as a primary strategy for some fish species to protect critical tissues largely independent of environmental conditions.</div></div><div><h3>Summary</h3><div>White sturgeon were exposed to two levels of elevated CO₂ (1 and 4 kPa) in water of two different pH values, and we tracked pH compensatory responses over the following two days. Acidifying water at modest CO₂ levels within the limit for complete compensation reduced the rate at which blood pH recovered. Alkalizing water during severe hypercapnia typically beyond that limit increased both the magnitude and the rate of organismal pH compensation. Intracellular pH protection was unaffected by any treatment.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"307 ","pages":"Article 111900"},"PeriodicalIF":2.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144523508","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}

{"title":"Corrigendum to “Temporal changes in PTTH/Egf signaling and ERK target gene expressions during chilling-induced diapause termination in Bombyx mori eggs” [Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, Volume 307, September 2025, 111,884].","authors":"Shi-Hong Gu","doi":"10.1016/j.cbpa.2025.111895","DOIUrl":"10.1016/j.cbpa.2025.111895","url":null,"abstract":"","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"307 ","pages":"Article 111895"},"PeriodicalIF":2.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144320967","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}

{"title":"Pharmacology reveals neuropeptide Y as a novel differential regulator of adrenal steroids in the globally invasive red-eared slider turtle (Trachemys scripta elegans)","authors":"Yoke Tassent,&nbsp;H. Bobby Fokidis","doi":"10.1016/j.cbpa.2025.111882","DOIUrl":"10.1016/j.cbpa.2025.111882","url":null,"abstract":"<div><div>The regulation of adrenal steroid secretion during acute stress has been poorly explored in reptiles. Using pharmacological manipulations of adrenocorticotropic hormone (ACTH), dexamethasone (DEX), neuropeptide Y (NPY), and NPY receptor antagonists, we examined glucocorticoid and DHEA responses to identify pathways potentially linking stress adaptation and energy homeostasis in the red-eared slider (<em>Trachemys scripta elegans</em>). Acute handling stress increased corticosterone concentrations as did injection with ACTH, but NPY and receptor antagonist treatments prevented this endogenous increase in corticosterone. In contrast, cortisol, and DHEA were not impacted by handling stress or ACTH, but both steroids increased in response to injection with NPY and with an established Y2 receptor antagonist. Together these data reveal the possibility that both ACTH and NPY act to regulate adrenal steroid synthesis, through a complicated and currently poorly understood mechanism. As red-eared sliders are highly invasive on a global scale, these insights can enhance our understanding of reptilian stress physiology to inform management strategies as well as bridge the gap between fundamental biology and applied conservation efforts, demonstrating the broader value of integrative research in addressing ecological and biomedical challenges.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"307 ","pages":"Article 111882"},"PeriodicalIF":2.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144200895","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}

{"title":"Characterization of the fatty acid composition of Pacific bluefin tuna Thunnus orientalis larvae by body part and depending on growth rate","authors":"Yuko Hiraoka ,&nbsp;Hiroshi Hashimoto ,&nbsp;Tetsuya Takatsu ,&nbsp;Yuki Koide ,&nbsp;Yosuke Tanaka ,&nbsp;Yasuhiro Ando","doi":"10.1016/j.cbpa.2025.111897","DOIUrl":"10.1016/j.cbpa.2025.111897","url":null,"abstract":"<div><div>In this study, we aimed to elucidate the characteristics of faster-growing Pacific bluefin tuna (<em>Thunnus orientalis)</em> larvae by focusing on the localization of long-chain polyunsaturated fatty acids in different body parts and at various days post-hatch (dph). To accomplish this, we compared low- and high-growth-rate groups of larvae under mass-rearing conditions. Multivariate analysis revealed that the first axis separated the dph and growth groups, and the high-growth-rate group tended to be distributed on the same side at 20 dph. This suggests that the faster-growing larvae had switched their diet sooner after the change in feeding regime, either from rotifers to yolk-sac larvae of the spangled emperor (<em>Lethrinus nebulosus</em>) or from yolk-sac larvae to a commercial diet. However, the fatty acid compositions differed significantly between the two growth groups at 10 dph, before the change in feeding regime (PERMANOVA; <em>P</em> &lt; 0.001). Notably, %DHA was higher in the head (mean: 24.4 %) and eyes (29.2 %) of the high-growth group, while %DHA levels in the trunk remained similar between groups (range: 23.1 %–23.7 %). These findings suggest that early accumulation of DHA (approximately 30 %) in the eyes, in contrast to the lower requirement in trunk tissues, may be critical for sustaining rapid growth in Pacific bluefin larvae during the pre-diet-shift period.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"307 ","pages":"Article 111897"},"PeriodicalIF":2.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144369613","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}

{"title":"The effects of individual differences in anxiety on anti-predator responses, thermal and hypoxia tolerance in zebrafish (Danio rerio)","authors":"Xiao-hong Li,&nbsp;Cheng Fu,&nbsp;Xue-ting Tan,&nbsp;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}

{"title":"Characterization of the IGFBP-rP cDNA and its associations with growth traits in Macrobrachium rosenbergii","authors":"Qianqian Ding,&nbsp;Yifan He,&nbsp;Weifeng Gao,&nbsp;Xiaojian Gao,&nbsp;Yao Zhang,&nbsp;Xiaojun Zhang,&nbsp;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}