Pub Date : 2025-02-21DOI: 10.1016/j.cbpa.2025.111829
Jenna M Drummond, W Gary Anderson, Alyssa M Weinrauch
We assessed the functional role of the spiral valve in carbohydrate digestion and glucose acquisition during different feeding states in Acipenser fulvescens and Squalus suckleyi. For S. suckleyi, maltase activity was highest in the anterior and mid spiral valve, while sodium-glucose linked transporter 1 (sglt1) transcripts peaked in the mid spiral valve. Alongside these metrics, glucose tissue uptake demonstrated decreased maximal transport rates from 24 h to 7+ days post feeding, demonstrating a putative means for energy conservation. A. fulvescens showed the highest maltase activity and sglt1 abundance in regions anterior to the spiral valve (pyloric ceca and anterior intestine). Additionally, glucose transport did not reach saturation in the spiral valve and anterior intestine of A. fulvescens over the measured concentrations, suggestive of a heightened capacity in these regions for glucose uptake. Overall, the spiral valve played a primary role in glucose digestion and transport in S. suckleyi, whereas A. fulvescens utilized the anterior intestine in addition to the spiral valve. Combined, these results also suggest regional functionality of carbohydrate acquisition within the spiral intestine in S. suckleyi but not in A. fulvescens. This demonstrates that the spiral valve may not always be the primary region of nutrient absorption in all species as suggested in the literature, highlighting the importance of comparing morphological and functional studies.
{"title":"Comparing glucose acquisition strategies between two ancient fish species: Lake sturgeon (Acipenser fulvescens) and North Pacific spiny dogfish (Squalus suckleyi).","authors":"Jenna M Drummond, W Gary Anderson, Alyssa M Weinrauch","doi":"10.1016/j.cbpa.2025.111829","DOIUrl":"https://doi.org/10.1016/j.cbpa.2025.111829","url":null,"abstract":"<p><p>We assessed the functional role of the spiral valve in carbohydrate digestion and glucose acquisition during different feeding states in Acipenser fulvescens and Squalus suckleyi. For S. suckleyi, maltase activity was highest in the anterior and mid spiral valve, while sodium-glucose linked transporter 1 (sglt1) transcripts peaked in the mid spiral valve. Alongside these metrics, glucose tissue uptake demonstrated decreased maximal transport rates from 24 h to 7+ days post feeding, demonstrating a putative means for energy conservation. A. fulvescens showed the highest maltase activity and sglt1 abundance in regions anterior to the spiral valve (pyloric ceca and anterior intestine). Additionally, glucose transport did not reach saturation in the spiral valve and anterior intestine of A. fulvescens over the measured concentrations, suggestive of a heightened capacity in these regions for glucose uptake. Overall, the spiral valve played a primary role in glucose digestion and transport in S. suckleyi, whereas A. fulvescens utilized the anterior intestine in addition to the spiral valve. Combined, these results also suggest regional functionality of carbohydrate acquisition within the spiral intestine in S. suckleyi but not in A. fulvescens. This demonstrates that the spiral valve may not always be the primary region of nutrient absorption in all species as suggested in the literature, highlighting the importance of comparing morphological and functional studies.</p>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":" ","pages":"111829"},"PeriodicalIF":2.1,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143484626","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 : 2025-02-19DOI: 10.1016/j.cbpa.2025.111828
Quan Yi, Liangyao Xiong
Organisms require various nutrients to provide energy, support growth, and maintain metabolic balance. Amino acid is among the most basic nutrients, serving as fundamental building blocks for protein synthesis while playing vital roles in growth, development, and reproduction. Understanding the mechanisms by which organisms perceive amino acids is key to unraveling how they select appropriate food sources and adapt to environmental challenges. The fruit fly, Drosophila melanogaster, serves as a powerful model for understanding fundamental genetic and physiological processes. This review focuses on recent advances in amino acid sensing mechanisms in Drosophila melanogaster and their relevance to feeding behavior, nutrient homeostasis, and adaptive responses, and integrates insights into peripheral sensory systems, such as the legs and proboscis, as well as internal regulatory mechanisms within the gut, fat body, and brain. It highlights key molecular players, including ionotropic receptors, gut-derived hormones, neuropeptides, and the microbiome-gut-brain axis. Additionally, the manuscript identifies knowledge gaps and proposes directions for future research, providing a comprehensive overview of this dynamic field.
{"title":"From sensory organs to internal pathways: A comprehensive review of amino acid sensing in Drosophila","authors":"Quan Yi, Liangyao Xiong","doi":"10.1016/j.cbpa.2025.111828","DOIUrl":"10.1016/j.cbpa.2025.111828","url":null,"abstract":"<div><div>Organisms require various nutrients to provide energy, support growth, and maintain metabolic balance. Amino acid is among the most basic nutrients, serving as fundamental building blocks for protein synthesis while playing vital roles in growth, development, and reproduction. Understanding the mechanisms by which organisms perceive amino acids is key to unraveling how they select appropriate food sources and adapt to environmental challenges. The fruit fly, <em>Drosophila melanogaster</em>, serves as a powerful model for understanding fundamental genetic and physiological processes. This review focuses on recent advances in amino acid sensing mechanisms in <em>Drosophila melanogaster</em> and their relevance to feeding behavior, nutrient homeostasis, and adaptive responses, and integrates insights into peripheral sensory systems, such as the legs and proboscis, as well as internal regulatory mechanisms within the gut, fat body, and brain. It highlights key molecular players, including ionotropic receptors, gut-derived hormones, neuropeptides, and the microbiome-gut-brain axis. Additionally, the manuscript identifies knowledge gaps and proposes directions for future research, providing a comprehensive overview of this dynamic field.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"303 ","pages":"Article 111828"},"PeriodicalIF":2.1,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143472724","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 : 2025-02-18DOI: 10.1016/j.cbpa.2025.111827
Geqi Gao , Dong Yang , Linyun Hu , Liang Jia , Donghong Niu
Aquaporins (AQPs) are a family of membrane proteins responsible for the selective transport of water molecules and other neutral metabolic substances across cell membranes. These proteins play a crucial role in osmoregulation, enabling marine bivalves to accommodate salinity fluctuations. However, the regulatory mechanism of AQPs in the razor clam (Sinonovacula constricta) under salinity stress remain unclear. In this study, we investigated the roles of two classical AQP genes, Classical aquaporins ScAQP4 and aquaglyceroporin ScAQP10, in response to hypotonic stress in S. constricta. ScAQP4 and ScAQP10 are hydrophobic proteins with six transmembrane domains and a highly conserved MIP structural motif. Upon acute hyposaline challenges, the expression of ScAQP4 and ScAQP10 in gills exhibited a significant increase in responses to low-salinity stress initially, followed by a gradual osmotic rebalance. To further investigate their biological functions, we conducted dsRNA interference to knockdown the expression levels of ScAQP4 and ScAQP10 in gill tissues and assessed the following physiological alternations. The knockdown of ScAQP4 and ScAQP10 resulted in a significant increase in heart rate and apoptosis and severe cellular damage of gills. These findings highlighted the critical roles of ScAQP4 and ScAQP10 in maintaining the osmotic balance of S. constricta. Collectively, these results propose a mechanism by which S. constricta regulates the expression of AQPs to accommodate salinity variations in the natural habitat.
{"title":"Molecular and physiological characterizations of razor clam (Sinonovacula constricta) aquaporin genes AQP4 and AQP10 in response to low-salinity tolerance","authors":"Geqi Gao , Dong Yang , Linyun Hu , Liang Jia , Donghong Niu","doi":"10.1016/j.cbpa.2025.111827","DOIUrl":"10.1016/j.cbpa.2025.111827","url":null,"abstract":"<div><div>Aquaporins (AQPs) are a family of membrane proteins responsible for the selective transport of water molecules and other neutral metabolic substances across cell membranes. These proteins play a crucial role in osmoregulation, enabling marine bivalves to accommodate salinity fluctuations. However, the regulatory mechanism of <em>AQPs</em> in the razor clam (<em>Sinonovacula constricta</em>) under salinity stress remain unclear. In this study, we investigated the roles of two classical <em>AQP</em> genes, Classical aquaporins <em>ScAQP4</em> and aquaglyceroporin <em>ScAQP10</em>, in response to hypotonic stress in <em>S. constricta</em>. <em><em>ScAQP4</em></em> and <em><em>ScAQP10</em></em> are hydrophobic proteins with six transmembrane domains and a highly conserved MIP structural motif. Upon acute hyposaline challenges, the expression of ScAQP4 and ScAQP10 in gills exhibited a significant increase in responses to low-salinity stress initially, followed by a gradual osmotic rebalance. To further investigate their biological functions, we conducted dsRNA interference to knockdown the expression levels of <em>ScAQP4</em> and <em>ScAQP10</em> in gill tissues and assessed the following physiological alternations. The knockdown of <em>ScAQP4</em> and <em>ScAQP10</em> resulted in a significant increase in heart rate and apoptosis and severe cellular damage of gills. These findings highlighted the critical roles of <em>ScAQP4</em> and <em>ScAQP10</em> in maintaining the osmotic balance of <em>S. constricta</em>. Collectively, these results propose a mechanism by which <em>S. constricta</em> regulates the expression of <em>AQPs</em> to accommodate salinity variations in the natural habitat.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"303 ","pages":"Article 111827"},"PeriodicalIF":2.1,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143470007","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}
Neuropeptide Y (NPY) is known to be a key regulator of reproductive functions across vertebrates. Its role in the modulation of gonadotropin releasing hormone (GnRH) has been extensively explored in mammals and fishes. However, no such report exists in aves, amphibians, or reptiles. Hence, the present study aimed to develop an insight into reproductive phase-dependent expression and role of NPY in the diencephalon region of male wall lizards. Expression of ligand, npy, and its receptor, npyr varied across the annual reproductive cycle of Hemidactylus flaviviridis with the highest expression of both observed during recrudescence. Further, the diencephalon region of recrudescent wall lizards treated with NPY demonstrated an increased mRNA level of gnrh and its receptor, gnrhr. In addition, the current study also elucidates hormonal regulation of diencephalonic npy and npyr wherein neuropeptides like kisspeptin and substance P, the gonadotropin, FSH, as well as sex steroids, dihydrotestosterone (DHT) and 17β-estradiol (E2) inhibited npy and npyr expression in the diencephalon region of wall lizards. With regard to adipokines, leptin stimulated while nesfatin-1 inhibited diencephalonic npy and npyr expression. In conclusion, the current study is the first to present a comprehensive picture of reproductive phase-specific expression pattern, role, and hormonal regulation of neuropeptide Y in the diencephalon region of the male wall lizard, H. flaviviridis.
{"title":"Neuropeptide Y at the crossroads of male reproductive functions in a seasonally breeding reptile, Hemidactylus flaviviridis","authors":"Vishesh Chauhan , Umesh Rai , Mamta Tripathy , Sunil Kumar","doi":"10.1016/j.cbpa.2025.111826","DOIUrl":"10.1016/j.cbpa.2025.111826","url":null,"abstract":"<div><div>Neuropeptide Y (NPY) is known to be a key regulator of reproductive functions across vertebrates. Its role in the modulation of gonadotropin releasing hormone (GnRH) has been extensively explored in mammals and fishes. However, no such report exists in aves, amphibians, or reptiles. Hence, the present study aimed to develop an insight into reproductive phase-dependent expression and role of NPY in the diencephalon region of male wall lizards. Expression of ligand, <em>npy,</em> and its receptor, <em>npyr</em> varied across the annual reproductive cycle of <em>Hemidactylus flaviviridis</em> with the highest expression of both observed during recrudescence. Further, the diencephalon region of recrudescent wall lizards treated with NPY demonstrated an increased mRNA level of <em>gnrh</em> and its receptor, <em>gnrhr</em>. In addition, the current study also elucidates hormonal regulation of diencephalonic <em>npy</em> and <em>npyr</em> wherein neuropeptides like kisspeptin and substance P, the gonadotropin, FSH, as well as sex steroids, dihydrotestosterone (DHT) and 17β-estradiol (E<sub>2</sub>) inhibited <em>npy</em> and <em>npyr</em> expression in the diencephalon region of wall lizards. With regard to adipokines, leptin stimulated while nesfatin-1 inhibited diencephalonic <em>npy</em> and <em>npyr</em> expression. In conclusion, the current study is the first to present a comprehensive picture of reproductive phase-specific expression pattern, role, and hormonal regulation of neuropeptide Y in the diencephalon region of the male wall lizard, <em>H. flaviviridis</em>.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"303 ","pages":"Article 111826"},"PeriodicalIF":2.1,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143460870","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 : 2025-02-14DOI: 10.1016/j.cbpa.2025.111825
Maria Teresa Muscari Tomajoli , Paola Di Donato , Vincenzo Della Corte , Giovanni Covone , Gianluca Fasciolo , Eugenio Geremia , Adriana Petito , Luca Tonietti , Laura Inno , Alessandra Rotundi , Paola Venditti , Gaetana Napolitano
Understanding the adaptation mechanisms of extremophiles to extreme environments is fundamental to predicting organisms' capacity to survive in space and plan future space exploration missions. This study explores the physiological and metabolic adaptations of nauplii of a eukaryotic organism, Artemia franciscana, hatched from cysts exposed to Mars-like pressure conditions (6 mbar) by analyzing aerobic and anaerobic metabolism, mitochondrial function, and oxidative stress in nauplii. Mars-like pressure did not inhibit nauplii's hatching or in vivo respiration, indicating that the fundamental metabolic functions are preserved but affected cellular metabolism. The lower lactate levels suggested reduced anaerobic metabolism, and the reduction in the activity of Complex I of the electron transport chain, resulting in reduced in vitro respiration supported by pyruvate plus malate, suggested an effect on aerobic metabolism. However, the succinate-supported respiration remained stable according to unchanged Complex II activity. Changes in aerobic metabolism could affect Reactive Oxygen Species (ROS) production and management. We did not observe changes in ROS levels according to the unchanged activity of NADPH oxidase, a source of ROS in the early development stages of nauplii. A total antioxidant capacity reduction and increased susceptibility to oxidants were observed despite this. However, lipid and protein oxidative stress markers levels remained unchanged, likely due to the increased activity of antioxidant enzymes. Our results underscore the resilience of the cysts to Mars-like pressure conditions, indicating the potential of Artemia franciscana as a model organism in astrobiological research, opening new avenues for exploration in astrobiology.
{"title":"The brine shrimp Artemia franciscana as a model for astrobiological studies: Physiological adaptations to Mars-like atmospheric pressure conditions","authors":"Maria Teresa Muscari Tomajoli , Paola Di Donato , Vincenzo Della Corte , Giovanni Covone , Gianluca Fasciolo , Eugenio Geremia , Adriana Petito , Luca Tonietti , Laura Inno , Alessandra Rotundi , Paola Venditti , Gaetana Napolitano","doi":"10.1016/j.cbpa.2025.111825","DOIUrl":"10.1016/j.cbpa.2025.111825","url":null,"abstract":"<div><div>Understanding the adaptation mechanisms of extremophiles to extreme environments is fundamental to predicting organisms' capacity to survive in space and plan future space exploration missions. This study explores the physiological and metabolic adaptations of nauplii of a eukaryotic organism, <em>Artemia franciscana</em>, hatched from cysts exposed to Mars-like pressure conditions (6 mbar) by analyzing aerobic and anaerobic metabolism, mitochondrial function, and oxidative stress in nauplii. Mars-like pressure did not inhibit nauplii's hatching or <em>in vivo</em> respiration, indicating that the fundamental metabolic functions are preserved but affected cellular metabolism. The lower lactate levels suggested reduced anaerobic metabolism, and the reduction in the activity of Complex I of the electron transport chain, resulting in reduced <em>in vitro</em> respiration supported by pyruvate plus malate, suggested an effect on aerobic metabolism. However, the succinate-supported respiration remained stable according to unchanged Complex II activity. Changes in aerobic metabolism could affect Reactive Oxygen Species (ROS) production and management. We did not observe changes in ROS levels according to the unchanged activity of NADPH oxidase, a source of ROS in the early development stages of nauplii. A total antioxidant capacity reduction and increased susceptibility to oxidants were observed despite this. However, lipid and protein oxidative stress markers levels remained unchanged, likely due to the increased activity of antioxidant enzymes. Our results underscore the resilience of the cysts to Mars-like pressure conditions, indicating the potential of <em>Artemia franciscana</em> as a model organism in astrobiological research, opening new avenues for exploration in astrobiology.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"303 ","pages":"Article 111825"},"PeriodicalIF":2.1,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143434405","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 : 2025-02-11DOI: 10.1016/j.cbpa.2025.111824
Cunrun Ye, Zhaoyang Ning, Tingting Hu, Xiaoyu Zhao, Weijie Mu
The Amur sleeper (Percottus glenii), a freeze tolerant fish species, can survive being frozen in ice, survival after recovery from freezing. This study investigated the role of melatonin in the recovery of Perccottus glenni following freezing. The fish were categorized into the following groups: non-treated control (Con), pinealectomy (Px), melatonin injection (Mlt), sham control (Sham), and saline injection control (Sal). The results revealed that the melatonin levels were affected by pinealectomy and melatonin injection. The liver and brain of the Px and Mlt groups exhibited autophagy after 4 h, along with the differential expression of endoplasmic reticulum stress-related genes. Furthermore, the activities of the mitochondrial complex initially increased at 4 h and then decreased by 12 h in the Px and Mlt groups, while antioxidant enzyme activities varied across groups and time points. These findings indicated that melatonin plays a key role in the recovery of P. glenni in a time-dependent manner, affecting autophagy, mitochondrial function, and antioxidant capacity. This study is the first to demonstrate melatonin's time-dependent role in facilitating the recovery of P. glenni after freezing, highlighting its critical involvement in modulating autophagy, mitochondrial function, and antioxidant processes. These findings shed light on the physiological mechanisms underlying freeze tolerance and recovery in fish, offering valuable insights for understanding and potentially enhancing the recovery processes in other species.
{"title":"Melatonin modulates autophagy, mitochondria and antioxidant in the liver and brain of Perccottus glenni during recovery from freezing","authors":"Cunrun Ye, Zhaoyang Ning, Tingting Hu, Xiaoyu Zhao, Weijie Mu","doi":"10.1016/j.cbpa.2025.111824","DOIUrl":"10.1016/j.cbpa.2025.111824","url":null,"abstract":"<div><div>The Amur sleeper (<em>Percottus glenii</em>), a freeze tolerant fish species, can survive being frozen in ice, survival after recovery from freezing. This study investigated the role of melatonin in the recovery of <em>Perccottus glenni</em> following freezing. The fish were categorized into the following groups: non-treated control (Con), pinealectomy (Px), melatonin injection (Mlt), sham control (Sham), and saline injection control (Sal). The results revealed that the melatonin levels were affected by pinealectomy and melatonin injection. The liver and brain of the Px and Mlt groups exhibited autophagy after 4 h, along with the differential expression of endoplasmic reticulum stress-related genes. Furthermore, the activities of the mitochondrial complex initially increased at 4 h and then decreased by 12 h in the Px and Mlt groups, while antioxidant enzyme activities varied across groups and time points. These findings indicated that melatonin plays a key role in the recovery of <em>P. glenni</em> in a time-dependent manner, affecting autophagy, mitochondrial function, and antioxidant capacity. This study is the first to demonstrate melatonin's time-dependent role in facilitating the recovery of <em>P. glenni</em> after freezing, highlighting its critical involvement in modulating autophagy, mitochondrial function, and antioxidant processes. These findings shed light on the physiological mechanisms underlying freeze tolerance and recovery in fish, offering valuable insights for understanding and potentially enhancing the recovery processes in other species.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"303 ","pages":"Article 111824"},"PeriodicalIF":2.1,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143403510","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 : 2025-02-10DOI: 10.1016/j.cbpa.2025.111823
Connor H. Reid , Raegan Davis , Kathleen M. Gilmour , Cheryl N. Klassen , James A. Crossman , Steven J. Cooke
Anaesthesia and/or immobilisation are typically required to facilitate experimental procedures on fishes such as the surgical implantation of electronic tags. Yet, optimal anaesthetic or immobilisation methods have primarily been developed and tested in teleosts, with relevant information on efficacy and suitability of these methods lacking for basal ray-finned fishes such as imperilled sturgeons (Acipenseridae). Here, we investigated the behavioural and physiological responses of hatchery-origin juvenile lake sturgeon (Acipenser fulvescens) to four immobilisation or anaesthetic methods. We conducted an experiment wherein fish were held in a fashion designed to induce tonic immobility, exposed to electroanaesthesia with a TENS unit, anaesthetised with MS-222, or anaesthetised with clove oil, and then subjected to a simulated intracoelomic tagging surgery. Following reflex indicator scoring, fish were “released” into a circular tank arena for behaviour trials and blood sampling at 0.5, 2, and 4 h post-release. Both tonic immobility and electroanaesthesia were ineffective at immobilising fish, and surgery under these methods led to relatively little behavioural impairment but the highest plasma cortisol peaks. Fish anaesthetised with MS-222 or clove oil had greater post-release behavioural impairment but lower cortisol levels. We discuss the implications of our findings for the practical application of these methods, and the challenges with identifying the most suitable method for immobilising or anaesthetising sturgeons in laboratory and field settings.
{"title":"Contrasting the effects of immobilisation and anaesthesia on the stress physiology and behaviour of juvenile lake sturgeon (Acipenser fulvescens)","authors":"Connor H. Reid , Raegan Davis , Kathleen M. Gilmour , Cheryl N. Klassen , James A. Crossman , Steven J. Cooke","doi":"10.1016/j.cbpa.2025.111823","DOIUrl":"10.1016/j.cbpa.2025.111823","url":null,"abstract":"<div><div>Anaesthesia and/or immobilisation are typically required to facilitate experimental procedures on fishes such as the surgical implantation of electronic tags. Yet, optimal anaesthetic or immobilisation methods have primarily been developed and tested in teleosts, with relevant information on efficacy and suitability of these methods lacking for basal ray-finned fishes such as imperilled sturgeons (Acipenseridae). Here, we investigated the behavioural and physiological responses of hatchery-origin juvenile lake sturgeon (<em>Acipenser fulvescens</em>) to four immobilisation or anaesthetic methods. We conducted an experiment wherein fish were held in a fashion designed to induce tonic immobility, exposed to electroanaesthesia with a TENS unit, anaesthetised with MS-222, or anaesthetised with clove oil, and then subjected to a simulated intracoelomic tagging surgery. Following reflex indicator scoring, fish were “released” into a circular tank arena for behaviour trials and blood sampling at 0.5, 2, and 4 h post-release. Both tonic immobility and electroanaesthesia were ineffective at immobilising fish, and surgery under these methods led to relatively little behavioural impairment but the highest plasma cortisol peaks. Fish anaesthetised with MS-222 or clove oil had greater post-release behavioural impairment but lower cortisol levels. We discuss the implications of our findings for the practical application of these methods, and the challenges with identifying the most suitable method for immobilising or anaesthetising sturgeons in laboratory and field settings.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"303 ","pages":"Article 111823"},"PeriodicalIF":2.1,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143403509","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}
Aquatic animals often exhibit glucose intolerance following a glucose load, and understanding the mechanisms of glucose uptake is crucial for elucidating the underlying processes. Sodium-dependent glucose transporter 1 (SGLT1) plays a crucial role in the process of intestinal glucose absorption and transport in vertebrates, but there is limited information about its function in crustaceans. This study identified the SGLT1 gene (named MrSGLT1) from Macrobrachium rosenbergii. The full cDNA sequence is 3764 bp, encoding 903 amino acids. Unlike SGLT1 in most teleost fish, which have 14 transmembrane domains, MrSGLT1 protein has only 12. MrSGLT1 was predominantly expressed in the intestine, with its expression increasing after feeding. This was accompanied by elevated levels of glucose and trehalose in the hemolymph, and increased glycogen levels in the hepatopancreas. Silencing MrSGLT1 in vivo resulted in decreased glucose and trehalose levels in the hemolymph and reduced glycogen levels in the hepatopancreas, although muscle glycogen levels were unaffected. Moreover, knockdown of MrSGLT1 led to increased expression of genes involved in glycogenolysis and decreased expression of genes associated with glycogenesis, inhibiting postprandial glycogen accumulation in the hepatopancreas. Feeding-induced glycolysis was also inhibited following MrSGLT1 silencing, while no significant changes were observed in gluconeogenesis-related genes. These findings highlight the critical role of MrSGLT1 in regulating postprandial glucose homeostasis in crustaceans.
{"title":"Molecular characterization and function of sodium-dependent glucose transporter 1 in postprandial glucose homeostasis in Macrobrachium rosenbergii","authors":"Qun Jiang, Wenjing Xu, Qianqian Ding, Xiaoyu Cai, Qi Dong, Xiaojian Gao, Yao Zhang, Xiaojun Zhang","doi":"10.1016/j.cbpa.2025.111822","DOIUrl":"10.1016/j.cbpa.2025.111822","url":null,"abstract":"<div><div>Aquatic animals often exhibit glucose intolerance following a glucose load, and understanding the mechanisms of glucose uptake is crucial for elucidating the underlying processes. Sodium-dependent glucose transporter 1 (<em>SGLT</em>1) plays a crucial role in the process of intestinal glucose absorption and transport in vertebrates, but there is limited information about its function in crustaceans. This study identified the <em>SGLT</em>1 gene (named <em>MrSGLT</em>1) from <em>Macrobrachium rosenbergii</em>. The full cDNA sequence is 3764 bp, encoding 903 amino acids. Unlike SGLT1 in most teleost fish, which have 14 transmembrane domains, MrSGLT1 protein has only 12. <em>MrSGLT</em>1 was predominantly expressed in the intestine, with its expression increasing after feeding. This was accompanied by elevated levels of glucose and trehalose in the hemolymph, and increased glycogen levels in the hepatopancreas. Silencing <em>MrSGLT</em>1 in vivo resulted in decreased glucose and trehalose levels in the hemolymph and reduced glycogen levels in the hepatopancreas, although muscle glycogen levels were unaffected. Moreover, knockdown of <em>MrSGLT</em>1 led to increased expression of genes involved in glycogenolysis and decreased expression of genes associated with glycogenesis, inhibiting postprandial glycogen accumulation in the hepatopancreas. Feeding-induced glycolysis was also inhibited following <em>MrSGLT</em>1 silencing, while no significant changes were observed in gluconeogenesis-related genes. These findings highlight the critical role of <em>MrSGLT</em>1 in regulating postprandial glucose homeostasis in crustaceans.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"302 ","pages":"Article 111822"},"PeriodicalIF":2.1,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143348519","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 : 2025-02-05DOI: 10.1016/j.cbpa.2025.111821
María Alborja-Valado , Mauro Chivite , Jessica Calo , Antía Verde , Carlos A. Ramírez-Rodríguez , Jesús M. Míguez , Marcos A. López Patiño
Environmental factors (daily light/dark cycles, food availability, etc.) entrain endogenous oscillators in living organisms, thereby allowing them to control the rhythms of behavioral and physiological functions, such as energy homeostasis. The gastrointestinal tract (GIT) is the first site of nutrient contact upon food intake. Thus, the GIT is key in energy homeostasis. Circadian oscillators exist within the GIT of mammals, modulating the daily function of the tissue. However, little information in this respect is available for other vertebrates, such as fish. Thus, we aimed to confirm the presence of a circadian oscillator within the GIT of rainbow trout (Oncorhynchus mykiss) and its interaction with locally released hormones that participate in feeding regulation in this species. We subsequently evaluated the role of food and light in synchronizing the rhythmic functioning of the GIT. According to our results, a circadian oscillator exists throughout the GIT of rainbow trout, based on the daily rhythms of clock gene (clock1a, bmal1b, per1, cry2 and reb-ervβ-like) mRNA abundance. Light influences the function of the circadian oscillator within the GIT, but food is a key factor as a synchronizer. The feeding time and the presence and/or absence of food synchronize the rhythmic function of the GIT, as observed for GIT hormones (Ghrelin, Glp1 and Cck). Understanding the functioning of the circadian machinery in peripheral organs such as the GIT will ultimately help to improve different aspects of aquaculture, from farming strategies to welfare, among others.
{"title":"A circadian clock controls the daily function of the intestine in rainbow trout. Influence of light and food as synchronizers","authors":"María Alborja-Valado , Mauro Chivite , Jessica Calo , Antía Verde , Carlos A. Ramírez-Rodríguez , Jesús M. Míguez , Marcos A. López Patiño","doi":"10.1016/j.cbpa.2025.111821","DOIUrl":"10.1016/j.cbpa.2025.111821","url":null,"abstract":"<div><div>Environmental factors (daily light/dark cycles, food availability, etc.) entrain endogenous oscillators in living organisms, thereby allowing them to control the rhythms of behavioral and physiological functions, such as energy homeostasis. The gastrointestinal tract (GIT) is the first site of nutrient contact upon food intake. Thus, the GIT is key in energy homeostasis. Circadian oscillators exist within the GIT of mammals, modulating the daily function of the tissue. However, little information in this respect is available for other vertebrates, such as fish. Thus, we aimed to confirm the presence of a circadian oscillator within the GIT of rainbow trout (<em>Oncorhynchus mykiss</em>) and its interaction with locally released hormones that participate in feeding regulation in this species. We subsequently evaluated the role of food and light in synchronizing the rhythmic functioning of the GIT. According to our results, a circadian oscillator exists throughout the GIT of rainbow trout, based on the daily rhythms of clock gene (<em>clock1a, bmal1b, per1, cry2</em> and <em>reb-ervβ-like</em>) mRNA abundance. Light influences the function of the circadian oscillator within the GIT, but food is a key factor as a synchronizer. The feeding time and the presence and/or absence of food synchronize the rhythmic function of the GIT, as observed for GIT hormones (Ghrelin, Glp1 and Cck). Understanding the functioning of the circadian machinery in peripheral organs such as the GIT will ultimately help to improve different aspects of aquaculture, from farming strategies to welfare, among others.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"303 ","pages":"Article 111821"},"PeriodicalIF":2.1,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143375043","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 : 2025-02-04DOI: 10.1016/j.cbpa.2025.111820
Rita A. Costa , Peter C. Hubbard , Manuel Manchado , Deborah M. Power , Zélia Velez
Increased carbon dioxide (CO2) in the ocean is changing seawater chemistry. Behavioural alterations in CO2 exposed fish have been linked to changes in the central nervous system (CNS). However, we hypothesise that receptor cells in direct contact with the environment are more susceptible to changes in water chemistry than the CNS. Electrophysiology, histology, and transcriptomics were used to explore the effect of exposure to CO2 acidified water on the olfactory epithelium (OE) of the Senegalese sole (Solea senegalensis). The upper and lower OE of this flatfish detect different odorants and are in contact with different environments. Acute exposure to acidified water decreased olfactory sensitivity more in the upper than in the lower OE. After chronic exposure to high CO2 there were no histological changes in the upper OE; however, in the lower OE, there was a massive infiltration of melanomacrophage (MMC) and tissue disorganization. In addition, in the upper OE, differential expressed gene transcripts (DETs) were related to inflammation and innate immune processes whereas in the lower OE, DETs were related to the adaptative immune response. Differential regulation of genes related to neurogenesis and plasticity occurred in both epithelia.
The effects of ocean acidification in sole OE depends on the nostril; however, the occurrence of an exacerbated immune response, OE remodelling and reduced sensitivity indicate that ocean acidification is likely to have significant and unpredictable consequences for behaviour.
{"title":"Olfactory specialization in the Senegalese sole (Solea senegalensis): CO2 acidified water triggers nostril-specific immune processes","authors":"Rita A. Costa , Peter C. Hubbard , Manuel Manchado , Deborah M. Power , Zélia Velez","doi":"10.1016/j.cbpa.2025.111820","DOIUrl":"10.1016/j.cbpa.2025.111820","url":null,"abstract":"<div><div>Increased carbon dioxide (CO<sub>2</sub>) in the ocean is changing seawater chemistry. Behavioural alterations in CO<sub>2</sub> exposed fish have been linked to changes in the central nervous system (CNS). However, we hypothesise that receptor cells in direct contact with the environment are more susceptible to changes in water chemistry than the CNS. Electrophysiology, histology, and transcriptomics were used to explore the effect of exposure to CO<sub>2</sub> acidified water on the olfactory epithelium (OE) of the Senegalese sole (<em>Solea senegalensis</em>). The upper and lower OE of this flatfish detect different odorants and are in contact with different environments. Acute exposure to acidified water decreased olfactory sensitivity more in the upper than in the lower OE. After chronic exposure to high CO<sub>2</sub> there were no histological changes in the upper OE; however, in the lower OE, there was a massive infiltration of melanomacrophage (MMC) and tissue disorganization. In addition, in the upper OE, differential expressed gene transcripts (DETs) were related to inflammation and innate immune processes whereas in the lower OE, DETs were related to the adaptative immune response. Differential regulation of genes related to neurogenesis and plasticity occurred in both epithelia.</div><div>The effects of ocean acidification in sole OE depends on the nostril; however, the occurrence of an exacerbated immune response, OE remodelling and reduced sensitivity indicate that ocean acidification is likely to have significant and unpredictable consequences for behaviour.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"302 ","pages":"Article 111820"},"PeriodicalIF":2.1,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143366760","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}
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