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

{"title":"A comparative study of tissue protein synthesis rates in an Antarctic, Harpagifer antarcticus and a temperate, Lipophrys pholis teleost","authors":"Keiron P.P. Fraser ,&nbsp;Lloyd S. Peck ,&nbsp;Melody S. Clark ,&nbsp;Andrew Clarke","doi":"10.1016/j.cbpa.2024.111650","DOIUrl":"10.1016/j.cbpa.2024.111650","url":null,"abstract":"<div><p>The affect of temperature on tissue protein synthesis rates has been reported in temperate and tropical, but not Antarctic fishes. Previous studies have generally demonstrated low growth rates in Antarctic fish species in comparison to temperate relatives and elevated levels of protein turnover. This study investigates how low temperatures effect tissue protein synthesis and hence tissue growth in a polar fish species. Groups of Antarctic, <em>Harpagifer antarcticus</em> and temperate, <em>Lipophrys pholis</em>, were acclimated to a range of overlapping water temperatures and protein synthesis was measure in white muscle (WM), liver and gastrointestinal tract (GIT). WM protein synthesis rates increased linearly with temperature in both species (<em>H. antarcticus</em> 0.16–0.23%.d⁻¹, <em>L. pholis</em>, 0.31–0.76%.d⁻¹), while liver (<em>H. antarcticus</em> 0.24–0.27%.d⁻¹, <em>L. pholis</em>, 0.44–1.03%.d⁻¹) and GIT were unaffected by temperature in <em>H. antarcticus</em> but increased non-linearly in <em>L.</em> <em>pholis</em> (<em>H. antarcticus</em> 0.22–0.26%.d⁻¹, <em>L. pholis</em>, 0.40–0.86%.d⁻¹). RNA to protein ratios were unaffected by temperature in <em>H. antarcticus</em> but increased weakly, in <em>L.</em> <em>pholis</em> WM and liver. In <em>L.</em> <em>pholis</em>, RNA translational efficiency increased significantly with temperature in all tissues, but only in liver in <em>H. antarcticus</em>. At the overlapping temperature of 3 °C, protein synthesis (WM 26%, Liver, 39%, GIT, 35%) and RNA translational efficiency (WM 273%, Liver, 271%, GIT, 300%) were significantly lower in <em>H. antarcticus</em> than <em>L.</em> <em>pholis</em>, while RNA to protein ratios were significantly higher (WM 270%, Liver 170%, GIT 186%). Tissue specific effects of temperature are detectable in both species. This study provides the first evidence, that tissue protein synthesis rates are constrained in Antarctic fishes.</p></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1095643324000771/pdfft?md5=5764dea6ca5fd775defc779c50d80936&pid=1-s2.0-S1095643324000771-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140892954","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of temporal thermal stress on Penaeus vannamei: Growth performance and physiological plasticity.","authors":"Diana R. Barajas-Sandoval ,&nbsp;Cristina Escobedo-Fregoso ,&nbsp;Eduardo Quiroz-Guzmán ,&nbsp;Dariel Tovar-Ramírez ,&nbsp;Clara Adèle Py ,&nbsp;Alberto Peña-Rodríguez","doi":"10.1016/j.cbpa.2024.111653","DOIUrl":"10.1016/j.cbpa.2024.111653","url":null,"abstract":"<div><p>The present study evaluated the effect of temporal periods of hypothermia and hyperthermia, followed by an optimal temperature recovery phase on the growth, survival, and physiological response of <em>Penaeus vannamei</em>. Post-larvae were exposed to stress periods for 7 and 14 days at 22 °C and 32 °C each, followed by a recovery phase at 28 °C to complete seven experimental weeks, and were compared with a control group maintained at 28 °C. Weight gain, specific growth rate, feed intake, feed conversion ratio, and survival were weekly determined. Muscle, hepatopancreas, and hemolymph were sampled on the 14th day of the recovery phase for biochemical composition, and antioxidant and digestive enzyme activities determination. The shrimp presented a higher growth rate during short-term hyperthermia in contrast to shrimp under hypothermia that presented compensatory growth after thermal stress when the temperature was restored at 28 °C. Hyperthermia increased 12–13% the feed intake while this was diminished 21–29% by the hypothermia periods. Shrimp undergo metabolic adjustments following thermal stress, with short hypothermia increasing the lipase activity and lipid storage in the hepatopancreas, while short hyperthermia also enhances chymotrypsin activity and leads to higher protein and lipid accumulation. Conversely, prolonged hyperthermia induces greater energy consumption, depleting lipid and glycogen stores, while hypothermia causes scarce mobilization of energy reserves during recovery phase. Antioxidant enzyme activities were not affected by short-thermal stress (7d), while prolonged thermal stress (14d) significantly affected SOD, CAT, and GPx activities. The present study provides important insights into the physiological plasticity of <em>P. vannamei</em> during recovery from thermal stress.</p></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140877917","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 the predictability of acclimatory temperature on the growth and thermal tolerance of juvenile Spinibarbus sinensis","authors":"Cheng Fu,&nbsp;Ke-Ying Zhou,&nbsp;Yue Hu,&nbsp;Yong-Fei Zhang,&nbsp;Shi-Jian Fu","doi":"10.1016/j.cbpa.2024.111652","DOIUrl":"10.1016/j.cbpa.2024.111652","url":null,"abstract":"<div><p>Heated effluent injection, cold hypolimnetic water inputs from dams, and extreme weather events can lead to unpredictable temperature fluctuations in natural waters, impacting fish performance and fitness. We hypothesized that fish exposed to such unpredictable fluctuations would exhibit weaker growth and enhanced thermal tolerance compared to predictable conditions. Qingbo (<em>Spinibarbus sinensis</em>) was selected as the experimental subject in this study. The qingbo were divided into a constant temperature group (C, 22 ± 0.5 °C), a predictable temperature fluctuation group (PF, 22 ± 4 °C, first warming, then cooling within a day) and an unpredictable temperature fluctuation group (UF, 22 ± 4 °C, the order of warming or cooling is random). After 40 days of temperature acclimation, the growth, metabolic rate, spontaneous activity, thermal tolerance, plasma cortisol concentration and liver hsp70 level of the fish were measured. Unexpectedly, neither the PF nor the UF group showed decreased growth compared to the C group. This could be attributed to the fact that temperature variation did not lead to a substantial increase in basic energy expenditure. Furthermore, feeding rates increased due to temperature fluctuations, although the difference was not significant. Both the PF and UF groups exhibited increased upper thermal tolerance, but only the UF group exhibited improved lower thermal tolerance and higher liver hsp70 levels compared to the C group. The qingbo that experienced unpredictable temperature fluctuations had the best thermal tolerance among the 3 groups, which might have occurred because they had the highest level of hsp70 expression. This may safeguard fish against the potential lethal consequences of extreme temperatures in the future. These findings suggested that qingbo exhibited excellent adaptability to both predictable and unpredictable temperature fluctuations, which may be associated with frequent temperature fluctuations in its natural habitat.</p></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140855613","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":"Effects of fasting and environmental factors on appetite regulators in pond loach Misgurnus anguillicaudatus","authors":"Jannik Kuhn ,&nbsp;Annika Lindstrom ,&nbsp;Helene Volkoff","doi":"10.1016/j.cbpa.2024.111651","DOIUrl":"10.1016/j.cbpa.2024.111651","url":null,"abstract":"<div><p>The pond loach (<em>Misgurnus anguillicaudatus</em>) is an important aquaculture freshwater species, used as an ornamental fish, food source for humans and angling bait. Pond loaches are resistant to fasting and extreme environmental conditions, including temperature and low oxygen levels. Little is known about how these factors affect the feeding physiology and the endocrine regulation of feeding of loaches. In this study, we examined the effects of fasting, as well as increased temperature and decreased oxygen levels on food intake and transcript levels of appetite regulators. Fasted fish had lower blood glucose levels, and lower expression levels of intestine CCK and PYY, and brain CART1, but had higher levels of brain orexin and ghrelin than fed fish. Fish held at 30 °C had higher food intake, glucose levels, and mRNA levels of intestine CCK and PYY, and brain CART2, but lower brain orexin levels than fish at 20 °C. Fish held at low oxygen levels had a lower food intake, higher intestine CCKa and ghrelin, and brain orexin, CART2 and ghrelin mRNA expression levels than fish held at high O₂ levels. Our results suggest that fasting and high temperatures increase the expression of orexigenic and anorexigenic factors respectively, whereas the increase in expression of both orexigenic and anorexigenic factors in low O₂ environments might not be related to their role in feeding, but possibly to protection from tissue damage. The results of our study might shed new light on how pond loaches are able to cope with extreme environmental conditions such as low food availability, extreme temperatures and hypoxia.</p></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140860365","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":"Ammonia transport in the excretory system of mosquito larvae (Aedes aegypti): Rh protein expression and the transcriptome of the rectum","authors":"Andrea C. Durant ,&nbsp;Andrew Donini","doi":"10.1016/j.cbpa.2024.111649","DOIUrl":"https://doi.org/10.1016/j.cbpa.2024.111649","url":null,"abstract":"<div><p>The role of the mosquito excretory organs (Malpighian tubules, MT and hindgut, HG) in ammonia transport as well as expression and function of the Rhesus (Rh protein) ammonia transporters within these organs was examined in <em>Aedes aegypti</em> larvae and adult females. Immunohistological examination revealed that the Rh proteins are co-localized with V-type H⁺-ATPase (VA) to the apical membranes of MT and HG epithelia of both larvae and adult females. Of the two Rh transporter genes present in <em>A. aegypti</em>, <em>AeRh50–1</em> and <em>AeRh50–2</em>, we show using quantitative real-time PCR (qPCR) and an RNA in-situ hybridization (ISH) assay that <em>AeRh50–1</em> is the predominant Rh protein expressed in the excretory organs of larvae and adult females. Further assessment of AeRh50–1 function in larvae and adults using RNAi (i.e. dsRNA-mediated knockdown) revealed significantly decreased [NH₄⁺] (mmol l⁻¹) levels in the secreted fluid of larval MT which does not affect overall NH₄⁺ transport rates, as well as significantly decreased NH₄⁺ flux rates across the HG (haemolymph to lumen) of adult females. We also used RNA sequencing to identify the expression of ion transporters and enzymes within the rectum of larvae, of which limited information currently exists for this important osmoregulatory organ. Of the ammonia transporters in <em>A. aegypti</em>, <em>AeRh50–1</em> transcript is most abundant in the rectum thus validating our immunohistochemical and RNA ISH findings. In addition to enriched VA transcript (subunits A and d1) in the rectum, we also identified high Na⁺-K⁺-ATPase transcript (α subunit) expression which becomes significantly elevated in response to HEA, and we also found enriched carbonic anhydrase 9, inwardly rectifying K⁺ channel <em>Kir2a</em>, and Na⁺-coupled cation-chloride (Cl⁻) co-transporter <em>CCC2</em> transcripts. Finally, the modulation in excretory organ function and/or Rh protein expression was examined in relation to high ammonia challenge, specifically high environmental ammonia (HEA) rearing of larvae. NH₄⁺ flux measurements using the scanning-ion selective electrode (SIET) technique revealed no significant differences in NH₄⁺ transport across organs comprising the alimentary canal of larvae reared in HEA vs freshwater. Further, significantly increased VA activity, but not NKA, was observed in the MT of HEA-reared larvae. Relatively high Rh protein immunostaining persists within the hindgut epithelium, as well as the ovary, of females at 24–48 h post blood meal corresponding with previously demonstrated peak levels of ammonia formation. These data provide new insight into the role of the excretory organs in ammonia transport physiology and the contribution of Rh proteins in mediating ammonia movement across the epi","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140807151","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":"Dietary lipid sensing through fatty acid oxidation and chylomicron formation in the gastrointestinal tract of rainbow trout","authors":"Jessica Calo,&nbsp;Ayelén M. Blanco,&nbsp;José L. Soengas","doi":"10.1016/j.cbpa.2024.111638","DOIUrl":"https://doi.org/10.1016/j.cbpa.2024.111638","url":null,"abstract":"<div><p>In mammals, physiological processes related to lipid metabolism, such as chylomicron synthesis or fatty acid oxidation (FAO), modulate eating, highlighting the importance of energostatic mechanisms in feeding control. This study, using rainbow trout (<em>Oncorhynchus mykiss</em>) as model, aimed to characterize the role of FAO and chylomicron formation as peripheral lipid sensors potentially able to modulate feeding in fish. Fish fed with either a normal- (24%) or high- (32%) fat diet were intraperitoneally injected with water alone or containing etomoxir (inhibitor of FAO rate-limiting enzyme carnitine palmitoyl-transferase 1). First, feed intake levels were recorded. We observed an etomoxir-derived decrease in feeding at short times, but a significant increase at 48 h after treatment in fish fed normal-fat diet. Then, we evaluated putative etomoxir effects on the mRNA abundance of genes related to lipid metabolism, chylomicron synthesis and appetite-regulating peptides. Etomoxir treatment upregulated mRNA levels of genes related to chylomicron assembly in proximal intestine, while opposite effects occurred in distal intestine, indicating a clear regionalization in response. Etomoxir also modulated gastrointestinal hormone mRNAs in proximal intestine, upregulating <em>ghrl</em> in fish fed normal-fat diet and <em>pyy</em> and <em>gcg</em> in fish fed high-fat diet. These results provide evidence for an energostatic control of feeding related to FAO and chylomicron formation at the peripheral level in fish.</p></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1095643324000655/pdfft?md5=da9eeb5dfe0f91c5252c497524fdc776&pid=1-s2.0-S1095643324000655-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140646961","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Relatedness of hypoxia and hyperthermia tolerances in the Nile tilapia (Oreochromis niloticus) and their relationships with cardiac and gill traits","authors":"Jesslyn Akrokoh ,&nbsp;Jedida Osei Bediako ,&nbsp;Kelvin Fafanyo ,&nbsp;Harriya Musah-Yussif ,&nbsp;Audrey Korsah Asubonteng ,&nbsp;Henry Owusu Adjei ,&nbsp;Anthea Georgina Ama Ofori ,&nbsp;Peter Vilhelm Skov ,&nbsp;Kwasi Adu Obirikorang","doi":"10.1016/j.cbpa.2024.111648","DOIUrl":"https://doi.org/10.1016/j.cbpa.2024.111648","url":null,"abstract":"<div><p>In fish, thermal and hypoxia tolerances may be functionally related, as suggested by the oxygen- and capacity-limited thermal tolerance (OCLTT) concept, which explains performance failure at high temperatures due to limitations in oxygen delivery. In this study the interrelatedness of hyperthermia and hypoxia tolerances in the Nile tilapia (<em>Oreochromis niloticus</em>), and their links to cardiorespiratory traits were examined. Different groups of <em>O. niloticus</em> (<em>n</em> = 51) were subjected to hypoxia and hyperthermia challenges and the O₂ tension for aquatic surface respiration (ASR <em>p</em>O₂) and critical thermal maximum (CTmax) were assessed as measurement endpoints. Gill filament length, total filament number, ventricle mass, length and width were also measured. Tolerance to hypoxia, as evidenced by ASR <em>p</em>O₂ thresholds of the individual fish, was highly variable and varied between 0.26 and 3.39 kPa. ASR events increased more profoundly as O₂ tensions decreased below 2 kPa. The CTmax values recorded for the <em>O. niloticus</em> individuals ranged from 43.1 to 44.8 °C (Mean: 44.2 ± 0.4 °C). Remarkably, there was a highly significant correlation between ASR <em>p</em>O₂ and CTmax in <em>O. niloticus</em> (<em>r</em> = −0.76, <em>p</em> &lt; 0.0001) with ASR <em>p</em>O₂ increasing linearly with decreasing CTmax. There were, however, no discernible relationships between the measured cardiorespiratory properties and hypoxia or hyperthermia tolerances. The strong relationship between hypoxia and hyperthermia tolerances in this study may be related to the ability of the cardiorespiratory system to provide oxygen to respiring tissues under thermal stress, and thus provides some support for the OCLTT concept in this species, at least at the level of the entire organism.</p></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140641381","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":"Exploration of cell-cell interactions and the notch signaling pathway in the gonadal niche of Crassostrea gigas","authors":"Huihui Wang ,&nbsp;Hong Yu ,&nbsp;Qi Li","doi":"10.1016/j.cbpa.2024.111639","DOIUrl":"https://doi.org/10.1016/j.cbpa.2024.111639","url":null,"abstract":"<div><p>The Notch signaling pathway plays a pivotal role in governing cell fate determinations within the gonadal niche. This study provides an extensive elucidation of the male and female gonadal niches within <em>Crassostrea gigas</em>. Examination <em>via</em> transmission electron microscopy revealed the presence of desmosome-like connection not only between germ cells and niche cells but also among adjacent niche cells within the oyster gonad. Transcriptomic analysis identified several putative Notch pathway components, including <em>CgJAG1</em>, <em>CgNOTCH1</em>, <em>CgSuh</em>, and <em>CgHey1</em>. Phylogenetic analysis indicated a close evolutionary relationship between <em>CgJAG1</em>, <em>CgNOTCH1</em>, and <em>CgHey1</em> and Notch members present in <em>Drosophila</em>. Expression profiling results indicated a notable abundance of <em>CgHey1</em> in the gonads, while <em>CgJAG1</em> and <em>CgNOTCH1</em> displayed distinct expression patterns associated with sexual dimorphism. <em>In situ</em> hybridization findings corroborated the predominant expression of <em>CgJAG1</em> in male niche cells, while <em>CgNOTCH1</em> was expressed in both male and female germ cells, as well as female niche cells. These findings demonstrate the important role of the Notch signaling pathway in the gonadal niche of oysters.</p></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140622277","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":"Two hexokinases of the shrimp Penaeus (Litopenaeus) vannamei are differentially expressed during oxygen limited conditions","authors":"Marissa A. Flores-Sauceda,&nbsp;Lilia Leyva-Carrillo,&nbsp;Laura Camacho-Jiménez,&nbsp;Silvia Gómez-Jiménez,&nbsp;Alma B. Peregrino-Uriarte,&nbsp;Gloria Yepiz-Plascencia","doi":"10.1016/j.cbpa.2024.111637","DOIUrl":"https://doi.org/10.1016/j.cbpa.2024.111637","url":null,"abstract":"<div><p>The white shrimp <em>Penaeus (Litopenaeus) vannamei</em> is the most cultivated shrimp worldwide. Compared to other shrimp species, it has higher resistance to adverse conditions. During hypoxia, the shrimp reduces oxygen consumption and adjusts energy metabolism <em>via</em> anaerobic glycolysis, among other strategies. Hexokinase (HK) is the first enzyme of glycolysis and a key regulation point. In mammals and other vertebrates, there are several tissue-specific HK isoforms with differences in expression and enzyme activity. In contrast, crustacean HKs have been relatively little studied. We studied the <em>P. vannamei</em> HK isoforms during hypoxia and reoxygenation. We cloned two HK1 sequences named HK1-long (1455 bp) and HK1-short (1302 bp), and one HK2 (1344 bp). In normoxia, total HK1 expression is higher in hepatopancreas, while HK2 is higher in gills. Severe hypoxia (1 mg/L of DO) after 12 h exposure and 1 h of reoxygenation increased HK1 expression in both organs, but HK2 expression changed differentially. In hepatopancreas, HK2 expression increased in 6 and 12 h of hypoxia but diminished to normoxia levels after reoxygenation. In gills, HK2 expression decreased after 12 h of hypoxia. HK activity increased in hepatopancreas after 12 h hypoxia, opposite to gills. These results indicate that shrimp HK isoforms respond to hypoxia and reoxygenation in a tissue-specific manner. Intracellular glucose levels did not change in any case, showing the shrimp ability to maintain glucose homeostasis during hypoxia.</p></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140545721","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":"Effects of thermophily-relevant temperature variation and sex on digestive performance in pythons","authors":"Derek M. Benson,&nbsp;Dale F. DeNardo","doi":"10.1016/j.cbpa.2024.111636","DOIUrl":"https://doi.org/10.1016/j.cbpa.2024.111636","url":null,"abstract":"<div><p>Different physiological performances are often optimized at slightly varying temperatures, which can lead to ectotherms selecting higher body temperatures during certain physiological efforts (e.g., digestion, reproduction). Such thermophilic responses can lead to temperature-based tradeoffs between two physiological activities with differing optimal temperatures or between optimizing a physiological activity and water balance, as water loss is elevated at higher temperatures. For example, ectotherms will often select a higher body temperature after consuming a meal, but the extent to which body temperature is elevated after eating is affected by its hydric state. Despite this known hydration state-based suppression of thermophily associated with digestion, the impact of this reduced body temperature on digestion performance is unknown. Accordingly, we determined whether small, thermophily-relevant changes in body temperature impact digestive efficiency or passage time and whether sex influenced the extent of the effect. Eighteen (9 female and 9 male) Children's pythons (<em>Antaresia childreni</em>) each consumed a meal at three temperatures (29 °C, 30 °C, and 31 °C), and gut passage time and digestive efficiency were determined. We found that neither metric was affected by temperature over the range tested. However, digestive efficiency was significantly impacted by the interaction between sex and temperature with males having significantly lower digestive efficiency than females at 31 °C, but not 29 °C or 30 °C. Our results provide insight into the effects of temperature on digestive physiology across narrow temperature ranges as well as demonstrate a sex-based difference in digestive physiology.</p></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140348146","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}