Coulometric respirometry is a highly sensitive method for measuring O2 consumption in small organisms but is not in widespread use among physiologists. Here we describe a coulometric microrespirometer based on a digital environmental sensor inside a sealed glass chamber and controlled by an Arduino™ microcontroller. As O2 is consumed, exhaled CO2 is removed, causing pressure to decrease in the chamber. The sensor detects the decreased pressure, and the controller activates electrolytic production of O2, returning pressure to the initial value. O2 consumption is calculated from electrolytic charge transfer. The effects of developmental stage, body mass, and temperature on O2 consumption of Tenebrio molitor beetles were easily measured by the apparatus. This straightforward design is a significant innovation in that it provides continuous data regarding environmental conditions inside the experimental chamber, can be fabricated easily, and is adaptable to a wide range of uses.
{"title":"Measurement of oxygen consumption in Tenebrio molitor using a sensitive, inexpensive, sensor-based coulometric microrespirometer.","authors":"D. Sandstrom, B. Offord","doi":"10.1242/jeb.243966","DOIUrl":"https://doi.org/10.1242/jeb.243966","url":null,"abstract":"Coulometric respirometry is a highly sensitive method for measuring O2 consumption in small organisms but is not in widespread use among physiologists. Here we describe a coulometric microrespirometer based on a digital environmental sensor inside a sealed glass chamber and controlled by an Arduino™ microcontroller. As O2 is consumed, exhaled CO2 is removed, causing pressure to decrease in the chamber. The sensor detects the decreased pressure, and the controller activates electrolytic production of O2, returning pressure to the initial value. O2 consumption is calculated from electrolytic charge transfer. The effects of developmental stage, body mass, and temperature on O2 consumption of Tenebrio molitor beetles were easily measured by the apparatus. This straightforward design is a significant innovation in that it provides continuous data regarding environmental conditions inside the experimental chamber, can be fabricated easily, and is adaptable to a wide range of uses.","PeriodicalId":22458,"journal":{"name":"THE EGYPTIAN JOURNAL OF EXPERIMENTAL BIOLOGY","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90115632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Animals rely on their ability to perform certain tasks sufficiently well to survive, secure mates, and reproduce. Performance traits depend on morphology, and so morphological traits should predict performance, yet this relationship is often confounded by multiple competing performance demands. Males and females experience different selection pressures on performance, and the consequent sexual conflict over performance expression can either constrain performance evolution or drive sexual dimorphism in both size and shape. Furthermore, change in a single morphological trait may benefit some performance traits at the expense of others, resulting in functional trade-offs. Identifying general or sex-specific relationships between morphology and performance at the organismal level thus requires a multivariate approach, as individuals are products both of an integrated phenotype and the ecological environment in which they have developed and evolved. We estimated the multivariate morphology→performance gradient in wild-caught, green anoles (Anolis carolinensis) by measuring external morphology and fore- and hindlimb musculature, and mapping these morphological traits to seven measured performance traits that cover the broad range of ecological challenges faced by these animals (sprint speed, endurance, exertion distance, climbing power, jump power, cling force, and bite force). We demonstrate that males and females differ in their multivariate mapping of traits on performance, indicating that sex-specific ecological demands likely shape these relationships, but do not differ in performance integration.
{"title":"Sex-specific multivariate morphology/performance relationships in Anolis carolinensis.","authors":"M. N. Simon, Ann M Cespedes, S. Lailvaux","doi":"10.1242/jeb.243471","DOIUrl":"https://doi.org/10.1242/jeb.243471","url":null,"abstract":"Animals rely on their ability to perform certain tasks sufficiently well to survive, secure mates, and reproduce. Performance traits depend on morphology, and so morphological traits should predict performance, yet this relationship is often confounded by multiple competing performance demands. Males and females experience different selection pressures on performance, and the consequent sexual conflict over performance expression can either constrain performance evolution or drive sexual dimorphism in both size and shape. Furthermore, change in a single morphological trait may benefit some performance traits at the expense of others, resulting in functional trade-offs. Identifying general or sex-specific relationships between morphology and performance at the organismal level thus requires a multivariate approach, as individuals are products both of an integrated phenotype and the ecological environment in which they have developed and evolved. We estimated the multivariate morphology→performance gradient in wild-caught, green anoles (Anolis carolinensis) by measuring external morphology and fore- and hindlimb musculature, and mapping these morphological traits to seven measured performance traits that cover the broad range of ecological challenges faced by these animals (sprint speed, endurance, exertion distance, climbing power, jump power, cling force, and bite force). We demonstrate that males and females differ in their multivariate mapping of traits on performance, indicating that sex-specific ecological demands likely shape these relationships, but do not differ in performance integration.","PeriodicalId":22458,"journal":{"name":"THE EGYPTIAN JOURNAL OF EXPERIMENTAL BIOLOGY","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83233174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The venom glands of reptiles, particularly those of front-fanged advanced snakes, must satisfy conflicting biological demands: rapid synthesis of potentially labile and highly toxic proteins, storage in the gland lumen for long periods, stabilization of the stored secretions, immediate activation of toxins upon deployment and protection of the animal from the toxic effects of its own venom. This dynamic system could serve as a model for the study of a variety of different phenomena involving exocrine gland activation, protein synthesis, stabilization of protein products and secretory mechanisms. However, these studies have been hampered by a lack of a long-term model that can be propagated in the lab (as opposed to whole-animal studies). Numerous attempts have been made to extend the lifetime of venom gland secretory cells, but only recently has an organoid model been shown to have the requisite qualities of recapitulation of the native system, self-propagation and long-term viability (>1 year). A tractable model is now available for myriad cell- and molecular-level studies of venom glands, protein synthesis and secretion. However, venom glands of reptiles are not identical, and many differ very extensively in overall architecture, microanatomy and protein products produced. This Review summarizes the similarities among and differences between venom glands of helodermatid lizards and of rear-fanged and front-fanged snakes, highlighting those areas that are well understood and identifying areas where future studies can fill in significant gaps in knowledge of these ancient, yet fascinating systems.
{"title":"Venom production and secretion in reptiles.","authors":"S. Mackessy","doi":"10.1242/jeb.227348","DOIUrl":"https://doi.org/10.1242/jeb.227348","url":null,"abstract":"The venom glands of reptiles, particularly those of front-fanged advanced snakes, must satisfy conflicting biological demands: rapid synthesis of potentially labile and highly toxic proteins, storage in the gland lumen for long periods, stabilization of the stored secretions, immediate activation of toxins upon deployment and protection of the animal from the toxic effects of its own venom. This dynamic system could serve as a model for the study of a variety of different phenomena involving exocrine gland activation, protein synthesis, stabilization of protein products and secretory mechanisms. However, these studies have been hampered by a lack of a long-term model that can be propagated in the lab (as opposed to whole-animal studies). Numerous attempts have been made to extend the lifetime of venom gland secretory cells, but only recently has an organoid model been shown to have the requisite qualities of recapitulation of the native system, self-propagation and long-term viability (>1 year). A tractable model is now available for myriad cell- and molecular-level studies of venom glands, protein synthesis and secretion. However, venom glands of reptiles are not identical, and many differ very extensively in overall architecture, microanatomy and protein products produced. This Review summarizes the similarities among and differences between venom glands of helodermatid lizards and of rear-fanged and front-fanged snakes, highlighting those areas that are well understood and identifying areas where future studies can fill in significant gaps in knowledge of these ancient, yet fascinating systems.","PeriodicalId":22458,"journal":{"name":"THE EGYPTIAN JOURNAL OF EXPERIMENTAL BIOLOGY","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72615190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sarah K. Wooller, A. Anagnostopoulou, B. Kuropka, Michael Crossley, P. Benjamin, F. Pearl, I. Kemenes, G. Kemenes, Murat Eravci
Applications of key technologies in biomedical research, such as qRT-PCR or LC-MS based proteomics, are generating large biological (-omics) data sets which are useful for the identification and quantification of biomarkers in any research area of interest. Genome, transcriptome and proteome databases are already available for a number of model organisms including vertebrates and invertebrates. However, there is insufficient information available for protein sequences of certain invertebrates, such as the great pond snail Lymnaea stagnalis, a model organism that has been used highly successfully in elucidating evolutionarily conserved mechanisms of memory function and dysfunction. Here we used a bioinformatics approach to designing and benchmarking a comprehensive CNS proteomics database (LymCNS-PDB) for the identification of proteins from the CNS of Lymnaea by LC-MS based proteomics. LymCNS-PDB was created by using the Trinity TransDecoder bioinformatics tool to translate amino acid sequences from mRNA transcript assemblies obtained from a published Lymnaea transcriptomics database. The blast-style MMSeq2 software was used to match all translated sequences to UniProtKB sequences for molluscan proteins, including Lymnaea and other molluscs. LymCNS-PDB contains 9,628 identified matched proteins that were benchmarked by performing LC-MS based proteomics analysis with proteins isolated from the Lymnaea CNS. MS/MS analysis using the LymCNS-PDB database led to the identification of 3,810 proteins. Only 982 proteins were identified by using a non-specific molluscan database. LymCNS-PDB provides a valuable tool that will enable us to perform quantitative proteomics analysis of protein interactomes involved in several CNS functions in Lymnaea, including learning and memory and age-related memory decline.
{"title":"A combined bioinformatics and LC-MS based approach for the development and benchmarking of a comprehensive database of Lymnaea CNS proteins.","authors":"Sarah K. Wooller, A. Anagnostopoulou, B. Kuropka, Michael Crossley, P. Benjamin, F. Pearl, I. Kemenes, G. Kemenes, Murat Eravci","doi":"10.1242/jeb.243753","DOIUrl":"https://doi.org/10.1242/jeb.243753","url":null,"abstract":"Applications of key technologies in biomedical research, such as qRT-PCR or LC-MS based proteomics, are generating large biological (-omics) data sets which are useful for the identification and quantification of biomarkers in any research area of interest. Genome, transcriptome and proteome databases are already available for a number of model organisms including vertebrates and invertebrates. However, there is insufficient information available for protein sequences of certain invertebrates, such as the great pond snail Lymnaea stagnalis, a model organism that has been used highly successfully in elucidating evolutionarily conserved mechanisms of memory function and dysfunction. Here we used a bioinformatics approach to designing and benchmarking a comprehensive CNS proteomics database (LymCNS-PDB) for the identification of proteins from the CNS of Lymnaea by LC-MS based proteomics. LymCNS-PDB was created by using the Trinity TransDecoder bioinformatics tool to translate amino acid sequences from mRNA transcript assemblies obtained from a published Lymnaea transcriptomics database. The blast-style MMSeq2 software was used to match all translated sequences to UniProtKB sequences for molluscan proteins, including Lymnaea and other molluscs. LymCNS-PDB contains 9,628 identified matched proteins that were benchmarked by performing LC-MS based proteomics analysis with proteins isolated from the Lymnaea CNS. MS/MS analysis using the LymCNS-PDB database led to the identification of 3,810 proteins. Only 982 proteins were identified by using a non-specific molluscan database. LymCNS-PDB provides a valuable tool that will enable us to perform quantitative proteomics analysis of protein interactomes involved in several CNS functions in Lymnaea, including learning and memory and age-related memory decline.","PeriodicalId":22458,"journal":{"name":"THE EGYPTIAN JOURNAL OF EXPERIMENTAL BIOLOGY","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78035180","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The present study examined if 20-weeks high-fat diet (HFD) consumption had a temperature specific effect on the contractile performance and regional thermal sensitivity of isolated mouse soleus (SOL) and diaphragm (DIA) muscle. Four-week-old female CD-1 mice were randomly selected to consume either a standard laboratory diet or a standard laboratory diet in conjunction with a HFD for 20-weeks. Peripheral SOL and core DIA were isolated from each animal and maximal isometric force and work loop power were assessed at 20⁰C, 28⁰C, 35⁰C and 40⁰C. Increasing temperature to 35⁰C resulted in greater isometric stress, lower activation and relaxation time and higher work loop power in both muscles. A further increase in temperature to 40⁰C did not affect isometric force but increased work loop power output of the SOL. Conversely, isometric force of the DIA was reduced and work loop power maintained when temperature was increased to 40⁰C. HFD consumption resulted in greater isometric force and absolute work loop power of the SOL and reduced isometric stress of the DIA, effects that were less apparent at lower temperatures. When the relationship between temperature and each measure of contractile function was examined by linear regression, there was no difference in slope between the control or HFD groups for either SOL or DIA. These results indicate that whilst contractile function initially increases with temperature, the temperature to elicit maximal performance is muscle and contractile mode-specific. Furthermore, HFD effects on contractile function are temperature specific, but HFD does not influence the relationship between temperature and performance.
{"title":"High-fat diet affects measures of skeletal muscle contractile performance in a temperature specific manner but does not influence regional thermal sensitivity.","authors":"J. Tallis, R. James, L. Emma, V. Cox, J. Hurst","doi":"10.1242/jeb.244178","DOIUrl":"https://doi.org/10.1242/jeb.244178","url":null,"abstract":"The present study examined if 20-weeks high-fat diet (HFD) consumption had a temperature specific effect on the contractile performance and regional thermal sensitivity of isolated mouse soleus (SOL) and diaphragm (DIA) muscle. Four-week-old female CD-1 mice were randomly selected to consume either a standard laboratory diet or a standard laboratory diet in conjunction with a HFD for 20-weeks. Peripheral SOL and core DIA were isolated from each animal and maximal isometric force and work loop power were assessed at 20⁰C, 28⁰C, 35⁰C and 40⁰C. Increasing temperature to 35⁰C resulted in greater isometric stress, lower activation and relaxation time and higher work loop power in both muscles. A further increase in temperature to 40⁰C did not affect isometric force but increased work loop power output of the SOL. Conversely, isometric force of the DIA was reduced and work loop power maintained when temperature was increased to 40⁰C. HFD consumption resulted in greater isometric force and absolute work loop power of the SOL and reduced isometric stress of the DIA, effects that were less apparent at lower temperatures. When the relationship between temperature and each measure of contractile function was examined by linear regression, there was no difference in slope between the control or HFD groups for either SOL or DIA. These results indicate that whilst contractile function initially increases with temperature, the temperature to elicit maximal performance is muscle and contractile mode-specific. Furthermore, HFD effects on contractile function are temperature specific, but HFD does not influence the relationship between temperature and performance.","PeriodicalId":22458,"journal":{"name":"THE EGYPTIAN JOURNAL OF EXPERIMENTAL BIOLOGY","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78691109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
James C. Mouton, R. Duckworth, R. Paitz, T. E. Martin
Maternal hormones can shape offspring development and increase survival when predation risk is elevated. In songbirds, yolk androgens influence offspring growth and begging behaviors which can help mitigate offspring predation risk in the nest. Other steroids may also be important for responding to nest predation risk, but non-androgen steroids have been poorly studied. We used a nest predator playback experiment and liquid chromatography with tandem mass spectrometry (LC-MS-MS) to assess whether nest predation risk influences deposition of 10 yolk steroids. We found no clear evidence that yolk androgen deposition changed when perception of nest predation risk was experimentally increased. However, elevated nest predation risk led to decreased yolk progesterone deposition. Overall, our results suggest yolk progesterone may be more important than yolk androgens in responses to offspring predation risk and highlight new avenues for research.
{"title":"Nest predation risk and deposition of yolk steroids in a cavity nesting songbird: an experimental test.","authors":"James C. Mouton, R. Duckworth, R. Paitz, T. E. Martin","doi":"10.1242/jeb.243047","DOIUrl":"https://doi.org/10.1242/jeb.243047","url":null,"abstract":"Maternal hormones can shape offspring development and increase survival when predation risk is elevated. In songbirds, yolk androgens influence offspring growth and begging behaviors which can help mitigate offspring predation risk in the nest. Other steroids may also be important for responding to nest predation risk, but non-androgen steroids have been poorly studied. We used a nest predator playback experiment and liquid chromatography with tandem mass spectrometry (LC-MS-MS) to assess whether nest predation risk influences deposition of 10 yolk steroids. We found no clear evidence that yolk androgen deposition changed when perception of nest predation risk was experimentally increased. However, elevated nest predation risk led to decreased yolk progesterone deposition. Overall, our results suggest yolk progesterone may be more important than yolk androgens in responses to offspring predation risk and highlight new avenues for research.","PeriodicalId":22458,"journal":{"name":"THE EGYPTIAN JOURNAL OF EXPERIMENTAL BIOLOGY","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76187430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT The central nervous system utilizes tendon compliance of the intrinsic foot muscles to aid the foot's arch spring, storing and returning energy in its tendinous tissues. Recently, the intrinsic foot muscles have been shown to adapt their energetic contributions during a variety of locomotor tasks to fulfil centre of mass work demands. However, the mechanism by which the small intrinsic foot muscles are able to make versatile energetic contributions remains unknown. Therefore, we examined the muscle–tendon dynamics of the flexor digitorum brevis during stepping, jumping and landing tasks to see whether the central nervous system regulates muscle activation magnitude and timing to enable energy storage and return to enhance energetic contributions. In step-ups and jumps, energy was stored in the tendinous tissue during arch compression; during arch recoil, the fascicles shortened at a slower rate than the tendinous tissues while the foot generated energy. In step-downs and landings, the tendinous tissues elongated more and at greater rates than the fascicles during arch compression while the foot absorbed energy. These results indicate that the central nervous system utilizes arch compression to store elastic energy in the tendinous tissues of the intrinsic foot muscles to add or remove mechanical energy when the body accelerates or decelerates. This study provides evidence for an adaptive mechanism to enable the foot's energetic versatility and further indicates the value of tendon compliance in distal lower limb muscle–tendon units in locomotion.
{"title":"Flexor digitorum brevis utilizes elastic strain energy to contribute to both work generation and energy absorption at the foot","authors":"Ross E Smith, G. Lichtwark, L. Kelly","doi":"10.1242/jeb.243792","DOIUrl":"https://doi.org/10.1242/jeb.243792","url":null,"abstract":"ABSTRACT The central nervous system utilizes tendon compliance of the intrinsic foot muscles to aid the foot's arch spring, storing and returning energy in its tendinous tissues. Recently, the intrinsic foot muscles have been shown to adapt their energetic contributions during a variety of locomotor tasks to fulfil centre of mass work demands. However, the mechanism by which the small intrinsic foot muscles are able to make versatile energetic contributions remains unknown. Therefore, we examined the muscle–tendon dynamics of the flexor digitorum brevis during stepping, jumping and landing tasks to see whether the central nervous system regulates muscle activation magnitude and timing to enable energy storage and return to enhance energetic contributions. In step-ups and jumps, energy was stored in the tendinous tissue during arch compression; during arch recoil, the fascicles shortened at a slower rate than the tendinous tissues while the foot generated energy. In step-downs and landings, the tendinous tissues elongated more and at greater rates than the fascicles during arch compression while the foot absorbed energy. These results indicate that the central nervous system utilizes arch compression to store elastic energy in the tendinous tissues of the intrinsic foot muscles to add or remove mechanical energy when the body accelerates or decelerates. This study provides evidence for an adaptive mechanism to enable the foot's energetic versatility and further indicates the value of tendon compliance in distal lower limb muscle–tendon units in locomotion.","PeriodicalId":22458,"journal":{"name":"THE EGYPTIAN JOURNAL OF EXPERIMENTAL BIOLOGY","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77599930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-27DOI: 10.1101/2022.03.25.485754
Nicolas Nagloo, Jessica K. Mountford, Ben J. Gundry, N. Hart, Wayne I. L. Davies, S. Collin, J. Hemmi
The complex visually mediated behaviors of diurnal lizards are enabled by a retina typically containing five types of opsins with the potential for tetrachromatic color vision. Despite lizards using a wide range of color signals, the limited variation in photoreceptor spectral sensitivities across lizards suggests only weak selection for species-specific, spectral tuning of photoreceptors. Some species, however, have enhanced short wavelength sensitivity, which likely helps with the detection of signals rich in ultraviolet and short wavelengths. In this study, we examined the visual system of Tiliqua rugosa, which has a UV/blue tongue, to determine the spectral sensitivity of the eye and to gain insight into this species’ visual ecology. Electroretinograms coupled with spectral stimulation showed peak sensitivity at 560 nm with high similarity to other lizards at wavelengths greater than 530 nm. However, at shorter wavelengths, sensitivity is enhanced leading to a spectral sensitivity curve that is 28 nm broader (full width at half height) than other lizards studied so far. The width of the curve is partially explained by a population of photoreceptors that respond more strongly to low temporal frequencies with possible peaks in sensitivity between 460 and 470 nm suggesting that they are SWS2 photoreceptors. The lack of a peak in sensitivity at 360 nm at low temporal frequencies and under a monochromatic light that suppresses the response of LWS photoreceptors, suggests that the SWS1 photoreceptors are red-shifted. In addition, the yellow and green oil droplets that are common in other diurnal lizards appear to be missing and instead, only transparent and pale-yellow oil droplets are present. LWS photoreceptors are likely paired with pale-yellow oil droplets to produce LWS photoreceptors with wider spectral sensitivity curves than in other lizards. Opsin sequencing reveals SWS1, SWS2, RH1, RH2 and LWS opsin genes that are very similar to the visual opsins detected in the green anole, Anolis carolinensis, suggesting there is little change in the spectral sensitivity of photoreceptors compared to other diurnal lizards. Since we only obtained a partial sequence of the SWS1 opsin, we were unable to determine whether amino acid substitution at tuning sites could have played a role in red-shifting the SWS1 photoreceptor spectral sensitivity. Photoreceptor densities are typically higher in central and ventral retinal regions than in the dorsal retina suggesting that higher spatial sampling is necessary at eye level and above the animal than on the ground. However, the SWS1 photoreceptors do not follow this pattern potentially due to their low abundance making them less relevant to high acuity visual tasks. Our findings demonstrate that there are possibly multiple mechanisms acting synergistically in the visual system of T. rugosa to enhance short wavelength sensitivity between 360 and 530 nm. While it is tempting to suggest that this is an adaptation to
{"title":"Enhanced short-wavelength sensitivity in the blue-tongued skink Tiliqua rugosa","authors":"Nicolas Nagloo, Jessica K. Mountford, Ben J. Gundry, N. Hart, Wayne I. L. Davies, S. Collin, J. Hemmi","doi":"10.1101/2022.03.25.485754","DOIUrl":"https://doi.org/10.1101/2022.03.25.485754","url":null,"abstract":"The complex visually mediated behaviors of diurnal lizards are enabled by a retina typically containing five types of opsins with the potential for tetrachromatic color vision. Despite lizards using a wide range of color signals, the limited variation in photoreceptor spectral sensitivities across lizards suggests only weak selection for species-specific, spectral tuning of photoreceptors. Some species, however, have enhanced short wavelength sensitivity, which likely helps with the detection of signals rich in ultraviolet and short wavelengths. In this study, we examined the visual system of Tiliqua rugosa, which has a UV/blue tongue, to determine the spectral sensitivity of the eye and to gain insight into this species’ visual ecology. Electroretinograms coupled with spectral stimulation showed peak sensitivity at 560 nm with high similarity to other lizards at wavelengths greater than 530 nm. However, at shorter wavelengths, sensitivity is enhanced leading to a spectral sensitivity curve that is 28 nm broader (full width at half height) than other lizards studied so far. The width of the curve is partially explained by a population of photoreceptors that respond more strongly to low temporal frequencies with possible peaks in sensitivity between 460 and 470 nm suggesting that they are SWS2 photoreceptors. The lack of a peak in sensitivity at 360 nm at low temporal frequencies and under a monochromatic light that suppresses the response of LWS photoreceptors, suggests that the SWS1 photoreceptors are red-shifted. In addition, the yellow and green oil droplets that are common in other diurnal lizards appear to be missing and instead, only transparent and pale-yellow oil droplets are present. LWS photoreceptors are likely paired with pale-yellow oil droplets to produce LWS photoreceptors with wider spectral sensitivity curves than in other lizards. Opsin sequencing reveals SWS1, SWS2, RH1, RH2 and LWS opsin genes that are very similar to the visual opsins detected in the green anole, Anolis carolinensis, suggesting there is little change in the spectral sensitivity of photoreceptors compared to other diurnal lizards. Since we only obtained a partial sequence of the SWS1 opsin, we were unable to determine whether amino acid substitution at tuning sites could have played a role in red-shifting the SWS1 photoreceptor spectral sensitivity. Photoreceptor densities are typically higher in central and ventral retinal regions than in the dorsal retina suggesting that higher spatial sampling is necessary at eye level and above the animal than on the ground. However, the SWS1 photoreceptors do not follow this pattern potentially due to their low abundance making them less relevant to high acuity visual tasks. Our findings demonstrate that there are possibly multiple mechanisms acting synergistically in the visual system of T. rugosa to enhance short wavelength sensitivity between 360 and 530 nm. While it is tempting to suggest that this is an adaptation to","PeriodicalId":22458,"journal":{"name":"THE EGYPTIAN JOURNAL OF EXPERIMENTAL BIOLOGY","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82732639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Turko, Giulia S. Rossi, T. Blewett, S. Currie, D. Taylor, P. Wright, E. Standen
Understanding the mechanisms that create phenotypic variation within and among populations is a major goal of physiological ecology. Variation may be a consequence of functional trade-offs (i.e. improvement in one trait comes at the expense of another trait) or alternatively may reflect the intrinsic quality of an organism (i.e. some individuals are simply better overall performers than others). There is evidence for both ideas in the literature, suggesting that environmental context may mediate whether variation results from trade-offs or differences in individual quality. We tested this overarching "context-dependence" hypothesis by comparing the aquatic and terrestrial athletic performance of the amphibious fish Kryptolebias marmoratus captured from two contrasting habitats, a large pond and small burrows. Overall, pond fish were superior terrestrial athletes but burrow fish were better burst swimmers, suggestive of a performance trade-off at the population level. Within each population, however, there was no evidence of a performance trade-off. In burrow fish, athletic performance was positively correlated with muscle content and body condition, consistent with the individual quality hypothesis. In pond fish, there was only a relationship between glycolytic white muscle and aquatic burst performance. Notably, pond fish were in better body condition, which may mask relationships between condition and athletic performance. Overall, our data highlight that population-level trends are insufficient evidence for the existence of phenotypic trade-offs in the absence of similar within-population patterns. Furthermore, we only found evidence for the individual quality hypothesis in one population, suggesting that patterns of phenotypic covariance are context dependent.
{"title":"Context-dependent relationships between swimming, terrestrial jumping, and body composition in the amphibious fish Kryptolebias marmoratus.","authors":"A. Turko, Giulia S. Rossi, T. Blewett, S. Currie, D. Taylor, P. Wright, E. Standen","doi":"10.1242/jeb.243372","DOIUrl":"https://doi.org/10.1242/jeb.243372","url":null,"abstract":"Understanding the mechanisms that create phenotypic variation within and among populations is a major goal of physiological ecology. Variation may be a consequence of functional trade-offs (i.e. improvement in one trait comes at the expense of another trait) or alternatively may reflect the intrinsic quality of an organism (i.e. some individuals are simply better overall performers than others). There is evidence for both ideas in the literature, suggesting that environmental context may mediate whether variation results from trade-offs or differences in individual quality. We tested this overarching \"context-dependence\" hypothesis by comparing the aquatic and terrestrial athletic performance of the amphibious fish Kryptolebias marmoratus captured from two contrasting habitats, a large pond and small burrows. Overall, pond fish were superior terrestrial athletes but burrow fish were better burst swimmers, suggestive of a performance trade-off at the population level. Within each population, however, there was no evidence of a performance trade-off. In burrow fish, athletic performance was positively correlated with muscle content and body condition, consistent with the individual quality hypothesis. In pond fish, there was only a relationship between glycolytic white muscle and aquatic burst performance. Notably, pond fish were in better body condition, which may mask relationships between condition and athletic performance. Overall, our data highlight that population-level trends are insufficient evidence for the existence of phenotypic trade-offs in the absence of similar within-population patterns. Furthermore, we only found evidence for the individual quality hypothesis in one population, suggesting that patterns of phenotypic covariance are context dependent.","PeriodicalId":22458,"journal":{"name":"THE EGYPTIAN JOURNAL OF EXPERIMENTAL BIOLOGY","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82995854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The transition from freshwater to seawater represents a physiological challenge for Atlantic salmon smolts preparing for downstream migration. Stressors occurring during downstream migration to the ocean impair the ability of smolts to maintain osmotic/ionic homeostasis in seawater. The molecular mechanisms underlying this interaction are not fully understood, especially at the organ-level. We combined RNA-seq with measures of whole animal homeostasis to examine gene expression dynamics in the gills of smolts associated with impaired seawater tolerance after an aquaculture-related stressor. Smolts were given a 24 h seawater tolerance test before and after exposure to an acute handling/confinement stress. RNA-seq followed by Differential Expression and Weighted Gene Correlation Network Analysis (WGCNA) was used to quantify the transcriptional response of the gill to handling/confinement stress, seawater, and their interaction. Exposure to acute stress was associated with a general stress response and impaired osmotic/ionic homeostasis in seawater. We identified gene networks in the gill exhibiting response to acute stress alone, seawater alone, and others exhibiting combined effects of both stress and seawater. Our findings indicate that acute handling/confinement stress increases the intensity of seawater-related gene expression and suggest that increased investment in mechanisms related to ion transport may be part of a compensatory response to impaired seawater tolerance in smolts.
{"title":"Network analysis reveals that acute stress exacerbates gene regulatory responses of the gill to seawater in Atlantic salmon.","authors":"M. Y. Monette, Jonathan P. Velotta","doi":"10.1242/jeb.242424","DOIUrl":"https://doi.org/10.1242/jeb.242424","url":null,"abstract":"The transition from freshwater to seawater represents a physiological challenge for Atlantic salmon smolts preparing for downstream migration. Stressors occurring during downstream migration to the ocean impair the ability of smolts to maintain osmotic/ionic homeostasis in seawater. The molecular mechanisms underlying this interaction are not fully understood, especially at the organ-level. We combined RNA-seq with measures of whole animal homeostasis to examine gene expression dynamics in the gills of smolts associated with impaired seawater tolerance after an aquaculture-related stressor. Smolts were given a 24 h seawater tolerance test before and after exposure to an acute handling/confinement stress. RNA-seq followed by Differential Expression and Weighted Gene Correlation Network Analysis (WGCNA) was used to quantify the transcriptional response of the gill to handling/confinement stress, seawater, and their interaction. Exposure to acute stress was associated with a general stress response and impaired osmotic/ionic homeostasis in seawater. We identified gene networks in the gill exhibiting response to acute stress alone, seawater alone, and others exhibiting combined effects of both stress and seawater. Our findings indicate that acute handling/confinement stress increases the intensity of seawater-related gene expression and suggest that increased investment in mechanisms related to ion transport may be part of a compensatory response to impaired seawater tolerance in smolts.","PeriodicalId":22458,"journal":{"name":"THE EGYPTIAN JOURNAL OF EXPERIMENTAL BIOLOGY","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82232617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：