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

{"title":"Cold temperature delays ovarian development of largemouth bass by inhibiting sex hormone release, angiogenesis, apoptosis and autophagy during out-of-season reproduction","authors":"Kuo He ,&nbsp;Zhihong Li ,&nbsp;Haoxiao Yan,&nbsp;Longlong Shi,&nbsp;Hangyu Yang,&nbsp;Qiao Liu,&nbsp;Kaige Song,&nbsp;Yifan Hu,&nbsp;Bo Wang,&nbsp;Song Yang,&nbsp;Liulan Zhao","doi":"10.1016/j.cbpa.2024.111795","DOIUrl":"10.1016/j.cbpa.2024.111795","url":null,"abstract":"<div><div>Cold temperature is an effective method of achieving out-of-season reproduction and obtaining fry in the autumn. This study investigated the effects of low-temperature (12–16 °C) environment on the out-of-season reproduction of largemouth bass, particularly the delayed effects on ovarian development. During the period of delayed out-of-season reproduction, there was a significant reduction in the levels of serum sex hormones (FSH and LH) and their respective receptors (<em>FSHR</em> and <em>LHCGR</em>). Exposure to cold temperature significantly reduced the expression of gonadal development genes (<em>IGF-1</em>, <em>GDF9</em>, and <em>CDC2</em>) <em>(P&lt;0.05)</em> and diminished the vascular network on the ovarian membrane, as confirmed by angiogenesis-related analyses. In lipid metabolism, <em>AMH</em> mRNA levels decreased overall, while <em>HSD3B</em>, <em>FABP1</em>, <em>APOA1</em>, and <em>APOC2</em> initially increased before declining. Serum VTG levels decreased gradually with a slight increase post-spawning. These findings suggested that cold temperature delay ovarian development in largemouth bass by impacting sex hormone synthesis, angiogenesis, and lipid deposition. This insight enhances our understanding of out-of-season reproduction and guides the development of more effective reproductive techniques.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"301 ","pages":"Article 111795"},"PeriodicalIF":2.1,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142873107","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":"Coping with salinity change: How does the cyclopoid copepod Apocyclops royi (Lindberg 1940) do it?","authors":"Per M. Jepsen,&nbsp;Cæcilie H. Dinsen,&nbsp;Esther S.H. Øllgaard,&nbsp;Jonathan Y.B. Jedal,&nbsp;Lasse Aggerholm,&nbsp;Tor Salomonsen,&nbsp;Hans Ramløv","doi":"10.1016/j.cbpa.2024.111794","DOIUrl":"10.1016/j.cbpa.2024.111794","url":null,"abstract":"&lt;div&gt;&lt;div&gt;The cyclopoid copepod species &lt;em&gt;Apocyclops royi&lt;/em&gt; has attracted significant attention due to its importance in marine food webs and its role as a vital food source for many marine organisms, particularly marine fish larvae. This study aims to understand the activity patterns, osmoregulation mechanisms, and physiological adaptations of &lt;em&gt;A. royi&lt;/em&gt; in response to acute decreasing salinities. In total three experiments were conducted. The first two experiments both investigated behavioural change and survival as a function of acute decreasing salinities in the range from 32 to 0, with steps of salinity reductions of five. The third experiment investigated the correlation between internal and external osmolality in &lt;em&gt;A. royi&lt;/em&gt;, by using a novel method developed for the experiment.&lt;/div&gt;&lt;div&gt;The first experiment indicated that &lt;em&gt;A. royi&lt;/em&gt; behaviour and survival were not affected at salinities from 20 and higher. Surprisingly, some copepods were able to survive an acute decrease in salinity from 32 to 0.&lt;/div&gt;&lt;div&gt;The second experiment utilized, for the first time for this copepod species, an in situ Multispecies Freshwater Biomonitoring system, to further observe &lt;em&gt;A. royi's&lt;/em&gt; behaviour. The results showed that the system was able to monitor &lt;em&gt;A. royi&lt;/em&gt; activity level. The system both documented that &lt;em&gt;A. royi&lt;/em&gt; exhibit a statistically significant increase in activity levels in response to light. Furthermore, it provided knowledge about the temporal activity level of &lt;em&gt;A. royi&lt;/em&gt; as a function of acute decreases in salinities, providing insights into that &lt;em&gt;A. royi&lt;/em&gt; has an ∼3 h acclimatization time to an acute decrease from 32 to 0 salinity.&lt;/div&gt;&lt;div&gt;In the third experiment, the osmolality of the copepods' body fluids with relation to external osmolality was examined using a vapor pressure osmometer. In this context a new method to extract body fluids from &lt;em&gt;A. royi&lt;/em&gt; was developed. The body fluid osmolality of copepods exposed to three different salinities 10, 20 and 32 was examined. The results showed that &lt;em&gt;A. royi&lt;/em&gt; is an osmoconformer at a higher salinity 32 but initiates hyperregulation at a lower salinity 10. Furthermore, it was observed that when copepods were exposed to a salinity of 10, 1000 individuals (stage: C5 or adults) were needed to obtain one sample of body fluid (10 μL) whereas when exposed to a salinity of 32, 3000 individuals were required to extract the same amount of body fluid.&lt;/div&gt;&lt;div&gt;Overall, the findings demonstrated that &lt;em&gt;A. royi&lt;/em&gt; has a high tolerance for acute decreases in salinity, showcasing behavioural adaptations and osmoregulatory capabilities, at extreme salinities. These results contribute to our understanding of copepod physiology and their ability to thrive in various habitats. Further research is needed to fully comprehend the physiological mechanisms underlying &lt;em&gt;A. royi's&lt;/em&gt; adaptation abilities to acute decreases in salinity.&lt;/div&gt;&lt;","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"301 ","pages":"Article 111794"},"PeriodicalIF":2.1,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142873109","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":"In silico identification of neuropeptide genes encoded by the genome of Crassostrea virginica with a special emphasis on feeding-related genes","authors":"Emmanuelle Pales Espinosa ,&nbsp;Sarah Farhat ,&nbsp;Bassem Allam","doi":"10.1016/j.cbpa.2024.111792","DOIUrl":"10.1016/j.cbpa.2024.111792","url":null,"abstract":"<div><div>Suspension-feeding bivalves, including the oyster <em>Crassostrea virginica</em>, use mucosal lectins to capture food particles. For instance, oysters can increase the transcription of these molecules to enhance food uptake. However, the regulatory processes influencing food uptake remain unclear although likely involve neuropeptides. Information on the neuropeptidome of <em>C. virginica</em> is limited, hindering the comprehension of its physiology, including energy homeostasis. This study explored the genome of <em>C. virginica</em> to identify neuropeptide precursors in silico and compared these with orthologs from other mollusks. A special focus was given to genes with potential implication in feeding processes. qPCR was used to determine the main organs of transcription of feeding-related genes. To further probe the function of target neuropeptides, visceral ganglia extracts and synthetic NPF were injected into oysters to evaluate their impact on genes associated with feeding and energy homeostasis. A total of eighty-five neuropeptides genes were identified in <em>C. virginica</em> genome. About 50 % of these are suggested to play a role in feeding processes. qPCR analyses showed that visceral ganglia and digestive system are the main organs for the synthesis of feeding-related neuropeptides. Further, results showed that the transcription of several neuropeptide genes in the visceral ganglia, including NPF and insulin-like peptide, increased after starvation. Finally, the injection of visceral ganglia extracts and synthetic NPF increased the transcription of a mucosal lectin and a glycogen synthase, known to be involved in food capture and glucose storage. Overall, this study identifies key genes regulating oyster physiology, enhancing the understanding of the control of basic physiological mechanisms in <em>C. virginica</em>.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"301 ","pages":"Article 111792"},"PeriodicalIF":2.1,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142856732","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":"Small heat shock proteins as relevant biomarkers for anthropogenic stressors in earthworms","authors":"Natasha Tilikj ,&nbsp;Mercedes de la Fuente ,&nbsp;Ana Belén Muñiz-González ,&nbsp;José-Luis Martínez-Guitarte ,&nbsp;Patricia Caballero-Carretero ,&nbsp;Marta Novo","doi":"10.1016/j.cbpa.2024.111785","DOIUrl":"10.1016/j.cbpa.2024.111785","url":null,"abstract":"<div><div>Anthropogenic stressors in terrestrial ecosystems require focused research on adaptive responses in soil organisms such as <em>Eisenia fetida</em>, a model earthworm species. We analyzed the gene expression of five small heat shock proteins (sHSPs) in response to various stressors: heat stress (31 and 35 °C), desiccation (10 % and 20 % humidity), and chemical exposure (bisphenol A and endosulfan) under standard and elevated temperatures. Under moderate heat (31 °C), early upregulation of sHSP transcripts suggests their involvement in initial stress responses, possibly mitigating protein aggregation. At the higher temperature (35 °C), three sHSPs served as a defense against severe protein aggregation, a significant finding as previous studies identified only one activated heat shock protein (HSP70) in <em>E. fetida</em> under similar conditions. Desiccation stress at 10 % humidity activated more sHSPs than at 20 % humidity, and the expression profile at 10 % humidity closely resembled that observed under heat stress, suggesting overlapping adaptation pathways. Heat combined with chemical stress, particularly endosulfan, elevated sHSP transcription and underscored the potential of these proteins as biomarkers in multi-stressor environments. Monomeric sHSPs from <em>E. fetida</em>, which share homology with human sHSPs, showed the highest activity across all stressors, suggesting their key role in earthworm adaptation.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"300 ","pages":"Article 111785"},"PeriodicalIF":2.1,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142711810","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":"Short communication: Can Vitamin D be supplied from the large intestine?","authors":"David R. Fraser","doi":"10.1016/j.cbpa.2024.111784","DOIUrl":"10.1016/j.cbpa.2024.111784","url":null,"abstract":"<div><div>The discovery that vitamin D₂ is being generated by anaerobic microbial metabolism in the alimentary tract, raises the question whether such a source of vitamin D could contribute to vitamin D supply for the animal hosting this microbial production system. In ruminants, this microbial generation in the forestomach allows vitamin D₂ to be readily absorbed when it reaches the small intestine, contributing to vitamin D₂ and 25-hydroxyvitamin D₂ [25(OH)D₂] found in their tissues. In monogastric animals like humans, the microbial generation of vitamin D₂ is occurring in the large intestine. There is evidence that vitamin D hydroxy metabolites, delivered to the lumen of the colon can be absorbed. However, the parent vitamin D is more lipophilic than its metabolites, and like lipophilic vitamin K₂ being produced by bacteria in the hindgut, may be poorly absorbed by the colon mucosa. It is now apparent that colon mucosal cells have the proteins megalin and cubilin in their basal membrane. These glycoproteins perform endocytosis of circulating proteins including vitamin D binding protein [DBP]. Inside the cell, DBP binds to cytoplasmic actin and thus provides an array of high affinity binding sites for vitamin D and its functional metabolites. Any traces of vitamin D₂ that may diffuse into the colon mucosal cells from the lumen would thus be retained and accumulate on the DBP-actin. It would then be a substrate for functional hydroxylase metabolism for local endocrine action in these cells, and subsequent delivery of 25(OH)D₂ by diffusion to apo-DBP in the circulation.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"300 ","pages":"Article 111784"},"PeriodicalIF":2.1,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142711806","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":"Bioimaging and the future of whole-organismal developmental physiology","authors":"Oliver Tills,&nbsp;Ziad Ibbini,&nbsp;John I. Spicer","doi":"10.1016/j.cbpa.2024.111783","DOIUrl":"10.1016/j.cbpa.2024.111783","url":null,"abstract":"<div><div>While omics has transformed the study of biology, concomitant advances made at the level of the whole organism, <em>i.e.</em> the phenome, have arguably not kept pace with lower levels of biological organisation. In this personal commentary we evaluate the importance of imaging as a means of measuring whole organismal developmental physiology. Image acquisition, while an important process itself, has become secondary to image analysis as a bottleneck to the use of imaging in research. Here, we explore the significant potential for increasingly sophisticated approaches to image analysis, including deep learning, to advance our understanding of how developing animals grow and function. Furthermore, unlike many species-specific methodologies, tools and technologies, we explore how computer vision has the potential to be transferable between species, life stages, experiments and even taxa in which embryonic development can be imaged. We identify what we consider are six of the key challenges and opportunities in the application of computer vision to developmental physiology carried out in our lab, and more generally. We reflect on the tangibility of transferrable computer vision models capable of measuring the integrative physiology of a broad range of developing organisms, and thereby driving the adoption of phenomics for developmental physiology. We are at an exciting time of witnessing the move from computer vision as a replacement for manual observation, or manual image analysis, to it enabling a fundamentally more powerful approach to exploring and understanding the complex biology of developing organisms, the quantification of which has long posed a challenge to researchers.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"300 ","pages":"Article 111783"},"PeriodicalIF":2.1,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142711691","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":"Influence of temperature changes on oxidative stress and antioxidant defense system in the bay scallop, Argopecten irradians","authors":"Jin Ah Song ,&nbsp;Eunseong Lee ,&nbsp;Young-Ung Choi ,&nbsp;Jordan Jun Chul Park ,&nbsp;Jeonghoon Han","doi":"10.1016/j.cbpa.2024.111775","DOIUrl":"10.1016/j.cbpa.2024.111775","url":null,"abstract":"<div><div>In this study, we aimed to understand the effects of changes in temperature on biochemical and molecular responses associated with the antioxidant defense system in the bay scallop, <em>Argopecten irradians</em>. We measured the contents of H₂O₂ and malondialdehyde (MDA), as well as the activities of antioxidant enzymes (e.g., glutathione <em>S-</em>transferase [GST], superoxide dismutase [SOD], and catalase [CAT]), and the regulation of stress-related genes (e.g., <em>GST</em>, <em>SOD</em>, <em>CAT</em>, and heat shock protein 70 [<em>HSP70</em>]). In addition, total antioxidant capacity (TAC) was examined in scallops exposed to different temperatures. <em>A. irradians</em> showed high levels of H₂O₂ and MDA in response to acute thermal stress (48 and 72 h of exposure). Temperature changes also led to a significant increase in antioxidant enzyme activity and mRNA expression levels in <em>A. irradians</em>. Interestingly, the TAC increased in response to acute thermal stress (28 °C) for up to 12 h and decreased thereafter. The oxidative stress induced by high temperatures could not be alleviated by an increase in levels of antioxidant enzymes, such as GST, SOD, and CAT, resulting in high levels of H₂O₂ and MDA and low levels of TAC. In addition, significant changes (<em>P</em> &lt; 0.05) in <em>HSP70</em> levels were observed in response to changes in temperature, suggesting that HSP70 played an important role in the heat tolerance of <em>A. irradians</em>. In conclusion, <em>A. irradians</em> exhibits a greater degree of oxidative stress responses in high-temperature environments than that in low-temperature environments. Overall, these findings indicate that temperature changes lead to oxidative stress, resulting in cellular damage and activation of the antioxidant defense system in bay scallops. Further experiments are required to elucidate other antioxidants and fully understand the redox system in <em>A. irradians</em>.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"299 ","pages":"Article 111775"},"PeriodicalIF":2.1,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142633043","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 acute exposure to freshwater acidification on developing Oryzias latipes","authors":"Grace E. Wallace,&nbsp;Rosemary C. Minns,&nbsp;Caleb T. Hasler","doi":"10.1016/j.cbpa.2024.111774","DOIUrl":"10.1016/j.cbpa.2024.111774","url":null,"abstract":"<div><div>Elevated CO₂ in aquatic environments causes weak acidification. When exposed to weak acidification, regardless of life stage, most fishes undergo some degree of hypercapnia (elevation of CO₂ in the bloodstream). Hypercapnia negatively affects physiological processes and embryo and larval fish are particularly vulnerable to rises in CO₂. The aim of our study was to understand if weak acidification induced by elevated CO₂ alters the physiology and behaviour of freshwater Japanese medaka (<em>Oryzias latipes</em>) embryos and larvae. To test this, we treated Japanese medaka embryos and larvae for 24 h with varying levels of weak acidification (pH 7.1 [∼482 μatm], 6.4 [∼2,122 μatm], 6.1 [∼3,280 μatm], 5.8 [∼5,306 μatm], and 5.7 [∼10,130 μatm]) at two developmental stages (72 hpf and 9 dpf). Following the treatment, heart rate, burst activity (movement within the egg), and survival of embryos were quantified. Swimming activity of hatched larvae was also measured. We observed a statistically significant 2-fold decline in heart rate of embryonic Japanese medaka as pH decreased (<em>P</em> &lt; 0.01). We also found that survival of embryos significantly declined as acidification increased (<em>P</em> &lt; 0.01). Behaviour of larval fish was significantly altered (<em>P</em> &lt; 0.001) but not in a pH dependent manner. Our study suggests that weak acidification can cause negative effects to early life stage physiology and that behaviour can be altered. Our results suggest that if fish develop in weakly acidified freshwater there may be unfavourable impacts, including mortality at the most extreme levels.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"300 ","pages":"Article 111774"},"PeriodicalIF":2.1,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142633040","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":"Water fluxes and nutrient absorption along the midgut of three hemipterans, Mahanarva fimbriolata, Dysdercus peruvianus, and Rhodnius prolixus","authors":"Ignacio G. Barroso,&nbsp;Bárbara B. Nascimento,&nbsp;Clelia Ferreira,&nbsp;Walter R. Terra","doi":"10.1016/j.cbpa.2024.111773","DOIUrl":"10.1016/j.cbpa.2024.111773","url":null,"abstract":"<div><div>Hemiptera Order comprises insect species adapted to different diets regarding water and nutrient content and availability, thus suggesting different combinations of proteins to ensure their absorption. To find out whether hemipterans use the same or distinct set of proteins and whether these differences are related to the phylogeny or the diet, RNAseq analyses were conducted in gut sections of three hemipterans, <em>M. fimbriolata, D. peruvianus</em>, and <em>R. prolixus,</em> with remarkable distinct diet. Since only a few of the selected proteins were functionally characterized, the coded putative proteins were manually curated by bioinformatics to infer their physiological function. The results suggest a relationship between gene expression patterns and water and nutrient dietary content and availability. In contrast, putative gene expansions and deletions are related to phylogeny, corresponding to evolutionary adaptations of ancestral forms to feed on xylem, cotton seeds, and blood, resulting in more resemblances between <em>D. peruvianus</em> and <em>R. prolixus</em> than <em>M. fimbriolata. M. fimbriolata</em> absorbs water through aquaporins Drip and Prip in the filtration chamber by passive diffusion, with a higher contribution of water-selective Drip. <em>D. peruvianus</em> water absorption involves Drip and Prip, but Prip contribution appears to be higher, and they probably cooperate with water-ion cotransporters in the posterior midgut. <em>R. prolixus</em> absorbs water in the anterior midgut involving a sodium transporter and a putative water-urea Prip. Sugars, amino acids, and lipids might be absorbed along the midgut in the three species, with a higher contribution of the posterior midgut for amino acid and lipid absorption in <em>M. fimbriolata</em> and <em>D. peruvianus</em> and the middle midgut in <em>R. prolixus</em>.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"299 ","pages":"Article 111773"},"PeriodicalIF":2.1,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142633050","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":"Daily rhythms of locomotor activity and transcript levels of non-visual opsins in the brain of the blind Mexican cavefish (Astyanax mexicanus)","authors":"Francesca Conti ,&nbsp;Alba Vergès-Castillo ,&nbsp;Francisco J. Sánchez-Vázquez ,&nbsp;José F. López-Olmeda ,&nbsp;Cristiano Bertolucci ,&nbsp;José A. Muñoz-Cueto","doi":"10.1016/j.cbpa.2024.111772","DOIUrl":"10.1016/j.cbpa.2024.111772","url":null,"abstract":"<div><div>Most organisms possess endogenous circadian clocks that synchronise their physiology and behaviour with environmental cycles, with the light-dark (LD) cycle being the most potent synchronising signal. Consequently, it can be hypothesised that animals that have evolved in the dark, as in caves or deep sea, may no longer possess a functional light-entrained biological clock. In this research, the blind cavefish <em>Astyanax mexicanus</em> was selected as a model organism to investigate the potential effects of daily light conditions on the circadian timekeeping mechanisms. First, we focused on describing behavioural photic entrainment and the presence of a circadian endogenous rhythmicity by recording locomotor activity rhythms under different lighting regimes: LD 12:12, after a 6-h shift of LD, constant darkness (DD), and constant dim light (LLdim). Secondly, we aimed at characterising the mechanisms of photodetection by analysing the daily rhythms of expression of selected non-visual extraocular opsins (<em>exo-rhod</em>, <em>opn3</em>, <em>rgra</em>, <em>rgrb</em>, <em>tmt1a</em> and <em>tmt1b</em>) in the brain of this blind species using real-time quantitative PCR. Our results revealed that blind Mexican cavefish activity rhythms were entrained to the LD cycle, with a diurnal activity pattern that persisted in a circadian fashion under constant lighting conditions. Additionally, statistically significant daily variations and/or rhythms were observed in three out of the six non-visual opsin genes analysed (<em>opn3</em>, <em>rgra</em> and <em>tmt1b</em>), all of them displaying nocturnal acrophases. These findings suggest that daily rhythms in extraretinal non-visual opsins may be transducing daily photic cycles and contributing to the entrainment of locomotor activity and other light-synchronised rhythms in blind cavefish species.</div></div>","PeriodicalId":55237,"journal":{"name":"Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology","volume":"299 ","pages":"Article 111772"},"PeriodicalIF":2.1,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142590894","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}