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Patrick J Walsh - One of the best experts on this subject based on the ideXlab platform.
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a waterborne chemical cue from gulf Toadfish opsanus beta prompts pulsatile urea excretion in conspecifics
Physiology & Behavior, 2017Co-Authors: Jeremy Fulton, Christophe M R Lemoine, Carol Bucking, Kevin V Brix, Patrick J Walsh, Danielle M McdonaldAbstract:The Gulf Toadfish (Opsanus beta) has a fully functional ornithine urea cycle (O-UC) that allows it to excrete nitrogenous waste in the form of urea. Interestingly, urea is excreted in a pulse across the gill that lasts 1-3h and occurs once or twice a day. Both the stress hormone, cortisol, and the neurotransmitter, serotonin (5-HT) are involved in the control of pulsatile urea excretion. This and other evidence suggests that urea pulsing may be linked to Toadfish social behavior. The hypothesis of the present study was that Toadfish urea pulses can be triggered by waterborne chemical cues from conspecifics. Our findings indicate that exposure to seawater that held a donor conspecific for up to 48h (pre-conditioned seawater; PC-SW) induced a urea pulse within 7h in naive conspecifics compared to a pulse latency of 20h when exposed to seawater alone. Factors such as PC-SW intensity and donor body mass influenced the pulse latency response of naive conspecifics. Fractionation and heat treatment of PC-SW to narrow possible signal candidates revealed that the active chemical was both water-soluble and heat-stable. Fish exposed to urea, cortisol or 5-HT in seawater did not have a pulse latency that was significantly different than seawater alone; however, ammonia, perhaps in the form of NH4Cl, was found to be a factor in the pulse latency response of Toadfish to PC-SW and could be one component of a multi-component cue used for chemical communication in Toadfish. Further studies are needed to fully identify the chemical cue as well as determine its adaptive significance in this marine teleost fish.
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Address Correspondence and Proofs to:
2016Co-Authors: Clémence M. Veauvy, Patrick J Walsh, Yuxiang Wang, Miguel A. Pérez-pinzón, C. VeauvyAbstract:We compared the effect of hyperammonemia on NADH levels in brain slices, and on the rate of oxygen consumption from isolated non-synaptic brain mitochondria, in ammonia-sensitive Wistar rats with that in ammonia-tolerant gulf Toadfish (Opsanus beta). The NADH content was significantly decreased (12 % less than control after 45 min with 1 mM NH4Cl) in rat brain slices, but it was not affected in brain slices from Toadfish (with both 1 mM and 6 mM NH4Cl). The rates of oxygen consumption of different sets of enzymes of the electron transport chain (ETC; complexes I,II,III, and IV; II,III, and IV; and IV alone) were unaltered by hyperammonemic conditions in isolated non-synaptic mitochondria from either rats or Toadfish. These results lead us to conclude that the differing effects of ammonia on NADH levels in rat and Toadfish brain slices must be due to aspects other than the direct effects of ammonia on enzymes of the ETC. Additionally, since these effects were seen in vitro, our studies have enabled us to rule out the possibility that effects of ammonia on metabolism were via indirect systemic effects. These results are discussed in the context of current views on mechanisms of CNS damage in hyperammonemic states
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immunohistochemical localization of urea and ammonia transporters in two confamilial fish species the ureotelic gulf Toadfish opsanus beta and the ammoniotelic plainfin midshipman porichthys notatus
Cell and Tissue Research, 2013Co-Authors: Carol Bucking, Danielle M Mcdonald, Craig P. Smith, Susan L Edwards, Paul Tickle, Patrick J WalshAbstract:This study aims to illustrate potential transport mechanisms behind the divergent approaches to nitrogen excretion seen in the ureotelic Toadfish (Opsanus beta) and the ammoniotelic plainfin midshipman (Porichthys notatus). Specifically, we wish to confirm the expression of a urea transporter (UT), which is found in the gill of the Toadfish and which is responsible for the unique “pulsing” nature of urea excretion and to localize the transporter within specific gill cells and at specific cellular locations. Additionally, the localization of ammonia transporters (Rhesus glycoproteins; Rhs) within the gill of both the Toadfish and midshipman was explored. Toadfish UT (tUT) was found within Na+-K+-ATPase (NKA)-enriched cells, i.e., ionocytes (probably mitochondria-rich cells), especially along the basolateral membrane and potentially on the apical membrane. In contrast, midshipman UT (pnUT) immunoreactivity did not colocalize with NKA immunoreactivity and was not found along the filaments but instead within the lamellae. The cellular location of Rh proteins was also dissimilar between the two fish species. In Toadfish gills, the Rh isoform Rhcg1 was expressed in both NKA-reactive cells and non-reactive cells, whereas Rhbg and Rhcg2 were only expressed in the latter. In contrast, Rhbg, Rhcg1 and Rhcg2 were expressed in both NKA-reactive and non-reactive cells of midshipman gills. In an additional transport epithelium, namely the intestine, the expression of both UTs and Rhs was similar between the two species, with only subtle differences being observed.
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Interactions between cortisol and Rhesus glycoprotein expression in ureogenic Toadfish, Opsanus beta.
The Journal of experimental biology, 2012Co-Authors: Tamara M Rodela, Patrick J Walsh, M. Danielle Mcdonald, Kathleen M. GilmourAbstract:In their native environment, gulf Toadfish excrete equal quantities of ammonia and urea. However, upon exposure to stressful conditions in the laboratory (i.e. crowding, confinement or air exposure), Toadfish decrease branchial ammonia excretion and become ureotelic. The objective of this study was to determine the influences of cortisol and ammonia on ammonia excretion relative to expression of Rhesus (Rh) glycoproteins and the ammonia-fixing enzyme, glutamine synthetase (GS). In vivo infusions and/or injections were used to manipulate corticosteroid activity and plasma ammonia concentrations in ureotelic Toadfish. Metyrapone treatment to lower circulating cortisol levels resulted in a 3.5-fold elevation of ammonia excretion rates, enhanced mRNA expression of two of the Toadfish Rh isoforms (Rhcg1 and Rhcg2), and decreased branchial and hepatic GS activity. Correspondingly, cortisol infusion decreased ammonia excretion 2.5-fold, a change that was accompanied by reduced branchial expression of all Toadfish Rh isoforms (Rhag, Rhbg, Rhcg1 and Rhcg2) and a twofold increase in hepatic GS activity. In contrast, maintenance of high circulating ammonia levels by ammonia infusion enhanced ammonia excretion and Rh expression (Rhag, Rhbg and Rhcg2). Toadfish treated with cortisol showed an attenuated response to ammonia infusion with no change in Rh mRNA expression or GS activity. In summary, the evidence suggests that ammonia excretion in Toadfish is modulated by cortisol-induced changes in both Rh glycoprotein expression and GS activity.
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Diel Patterns of Nitrogen Excretion, Plasma Constituents, and Behavior in the Gulf Toadfish (Opsanus beta) in Laboratory versus Outdoor Mesocosm Settings
Physiological and biochemical zoology : PBZ, 2010Co-Authors: John F. Barimo, Patrick J Walsh, M. Danielle McdonaldAbstract:Abstract Nitrogen excretion by the gulf Toadfish (Opsanus beta) is of interest because of its high proportion of urea excretion compared with that of other teleosts. To better understand the factors influencing the timing of nitrogen excretion, the ratio of excreted urea∶ammonia, and the effector molecules regulating these processes, gulf Toadfish were subjected to a series of experiments that moved them progressively from internal laboratory to outdoor mesocosm settings while assessing their behavior, nitrogen excretion patterns, levels of plasma hormones/effectors, and other parameters. In confined flux chambers in both laboratory and outdoor settings, Toadfish nitrogen excretion was largely observed as urea pulses, with no apparent diel patterns to the pulses. Unrestrained Toadfish in mesocosms exhibited distinctly nocturnal behavior, remaining exclusively in shelters during the day but taking several forays out into the mesocosm at night. In contrast to nitrogen excretion patterns in chambers, urea an...
M. Danielle Mcdonald - One of the best experts on this subject based on the ideXlab platform.
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Do reproductive hormones control Gulf Toadfish pulsatile urea excretion
Comparative biochemistry and physiology. Part A Molecular & integrative physiology, 2019Co-Authors: Maria C. Cartolano, Yi Chng, M. Danielle McdonaldAbstract:Gulf Toadfish (Opsanus beta) can excrete the majority of their nitrogenous waste as urea in distinct pulses across their gill. Urea pulses are controlled by cortisol and serotonin (5-HT) and are believed to contain chemical signals that may communicate reproductive and/or social status. The objectives of this study were to determine if reproductive hormones are involved in controlling pulsatile urea excretion, and if Toadfish respond to prostaglandins as a chemical signal. Specifically, 11-ketotestosterone (11-KT), estradiol (E2), and the teleost pheromone prostaglandin E2 (PGE2) were investigated. Castration during breeding season did not affect pulsatile urea excretion but serial injections of 11-KT outside of breeding season did result in a 48% reduction in urea pulse size in fish of both sexes. Injections of E2 and PGE2, on the other hand, did not alter urea excretion patterns. Toadfish also did not pulse urea in response to waterborne exposure of PGE2 suggesting that this compound does not serve as a Toadfish pheromone alone. Toadfish have significantly higher plasma 5-HT during breeding season compared to the months following breeding season. Future research should focus on the composition of the chemical signal in Toadfish and the potential importance of seasonal changes in plasma 5-HT in Toadfish pulsatile urea excretion and teleost reproduction in general.
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The impact of acute PAH exposure on the Toadfish glucocorticoid stress response.
Aquatic toxicology (Amsterdam Netherlands), 2017Co-Authors: Aalekhya Reddam, Martin Grosell, Edward M. Mager, M. Danielle McdonaldAbstract:The objective of the present study was to determine whether the polycyclic aromatic hydrocarbons (PAHs) associated with the Deepwater Horizon (DWH) oil spill impacted the stress response of teleost fish. The hypothesis was that intraperitoneal (IP) treatment with PAHs associated with the DWH oil spill or waterborne exposure to DWH oil high energy water-accommodated fraction (HEWAF) would result in the downregulation of the stress response of Gulf Toadfish, Opsanus beta, a benthic marine teleost fish that resides in the Gulf of Mexico. In vivo plasma cortisol levels and adrenocorticotropic hormone (ACTH)-mediated cortisol secretion by in vitro isolated kidney tissue were measured. Toadfish at rest IP-treated with naphthalene had higher plasma cortisol compared to fluorene-treated and control fish; phenanthrene-treated fish tended to have higher plasma cortisol levels that fluorene-treated and controls. When subjected to an additional crowding stress, naphthalene and phenanthrene-treated fish were no longer able to mount a stress response compared to fluorene-treated and control fish, suggesting exhaustion of the stress response. Supporting this in vivo data, there tended to be less cortisol released by the kidney in vitro from naphthalene and phenanthrene-treated fish in response to ACTH compared to controls. In contrast, Toadfish at rest exposed to 3% Slick A HEWAF did not have significantly different plasma cortisol levels compared to controls. But, exposed fish did have significantly less cortisol released by the kidney in vitro in response to ACTH. When Toadfish were subjected to an additional stress, there were no significant differences in plasma cortisol or ACTH, suggesting the action of a secondary secretagogue to maintain plasma cortisol in vivo. Combined, these data suggest that in response to acute PAH exposure, there may be internalization or downregulation of the melanocortin 2 receptor (MC2R) that mediates the action of ACTH.
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The Toadfish serotonin 2A (5-HT(2A)) receptor: molecular characterization and its potential role in urea excretion.
Comparative biochemistry and physiology. Part A Molecular & integrative physiology, 2012Co-Authors: Edward M. Mager, Lea R. Medeiros, Anthony P. Lange, M. Danielle McdonaldAbstract:Based on early pharmacological work, the serotonin 2A (5-HT(2A)) receptor subtype is believed to be involved in the regulation of Toadfish pulsatile urea excretion. The goal of the following study was to characterize the Toadfish 5-HT(2A) receptor at a molecular level, to determine the tissues in which this receptor is predominantly expressed and to further investigate the pharmacological specificity of Toadfish pulsatile urea excretion by examining the effect of ketanserin, a 5-HT(2A) receptor antagonist, on resting rates of pulsatile urea excretion. The full-length Toadfish 5-HT(2A) receptor encodes a 496 amino acid sequence and shares 57-80% sequence identity to 5-HT(2A) receptors of other organisms, with 100% conservation among important ligand-binding residues. Toadfish 5-HT(2A) receptor mRNA expression was highest in the swim bladder and gonad, followed by the whole brain. All other tissues tested (esophagus, stomach, anterior intestine, posterior intestine, rectum, liver, kidney, heart, muscle and gill) had mRNA expression levels that were significantly less than whole brain. Toadfish 5-HT(2A) receptor mRNA expression within the brain was highest in the hindbrain, telencephalon and midbrain/diencephalon regions. Treatment with the 5-HT(2A) receptor antagonist, ketanserin, resulted in a significant decrease in the pulsatile component of spontaneous urea excretion due to a reduction in urea pulse size with no significant change in pulse frequency. These results lend further support for the 5-HT(2A) receptor in the regulation of pulsatile urea excretion in Toadfish.
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The Toadfish serotonin 2A (5-HT2A) receptor: molecular characterization and its potential role in urea excretion
Comparative Biochemistry and Physiology A-molecular & Integrative Physiology, 2012Co-Authors: Edward M. Mager, Lea R. Medeiros, Anthony P. Lange, M. Danielle McdonaldAbstract:Abstract Based on early pharmacological work, the serotonin 2A (5-HT 2A ) receptor subtype is believed to be involved in the regulation of Toadfish pulsatile urea excretion. The goal of the following study was to characterize the Toadfish 5-HT 2A receptor at a molecular level, to determine the tissues in which this receptor is predominantly expressed and to further investigate the pharmacological specificity of Toadfish pulsatile urea excretion by examining the effect of ketanserin, a 5-HT 2A receptor antagonist, on resting rates of pulsatile urea excretion. The full-length Toadfish 5-HT 2A receptor encodes a 496 amino acid sequence and shares 57–80% sequence identity to 5-HT 2A receptors of other organisms, with 100% conservation among important ligand-binding residues. Toadfish 5-HT 2A receptor mRNA expression was highest in the swim bladder and gonad, followed by the whole brain. All other tissues tested (esophagus, stomach, anterior intestine, posterior intestine, rectum, liver, kidney, heart, muscle and gill) had mRNA expression levels that were significantly less than whole brain. Toadfish 5-HT 2A receptor mRNA expression within the brain was highest in the hindbrain, telencephalon and midbrain/diencephalon regions. Treatment with the 5-HT 2A receptor antagonist, ketanserin, resulted in a significant decrease in the pulsatile component of spontaneous urea excretion due to a reduction in urea pulse size with no significant change in pulse frequency. These results lend further support for the 5-HT 2A receptor in the regulation of pulsatile urea excretion in Toadfish.
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Interactions between cortisol and Rhesus glycoprotein expression in ureogenic Toadfish, Opsanus beta.
The Journal of experimental biology, 2012Co-Authors: Tamara M Rodela, Patrick J Walsh, M. Danielle Mcdonald, Kathleen M. GilmourAbstract:In their native environment, gulf Toadfish excrete equal quantities of ammonia and urea. However, upon exposure to stressful conditions in the laboratory (i.e. crowding, confinement or air exposure), Toadfish decrease branchial ammonia excretion and become ureotelic. The objective of this study was to determine the influences of cortisol and ammonia on ammonia excretion relative to expression of Rhesus (Rh) glycoproteins and the ammonia-fixing enzyme, glutamine synthetase (GS). In vivo infusions and/or injections were used to manipulate corticosteroid activity and plasma ammonia concentrations in ureotelic Toadfish. Metyrapone treatment to lower circulating cortisol levels resulted in a 3.5-fold elevation of ammonia excretion rates, enhanced mRNA expression of two of the Toadfish Rh isoforms (Rhcg1 and Rhcg2), and decreased branchial and hepatic GS activity. Correspondingly, cortisol infusion decreased ammonia excretion 2.5-fold, a change that was accompanied by reduced branchial expression of all Toadfish Rh isoforms (Rhag, Rhbg, Rhcg1 and Rhcg2) and a twofold increase in hepatic GS activity. In contrast, maintenance of high circulating ammonia levels by ammonia infusion enhanced ammonia excretion and Rh expression (Rhag, Rhbg and Rhcg2). Toadfish treated with cortisol showed an attenuated response to ammonia infusion with no change in Rh mRNA expression or GS activity. In summary, the evidence suggests that ammonia excretion in Toadfish is modulated by cortisol-induced changes in both Rh glycoprotein expression and GS activity.
Michael L Fine - One of the best experts on this subject based on the ideXlab platform.
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Use of Passive Acoustics for Assessing Behavioral Interactions in Individual Toadfish
Transactions of the American Fisheries Society, 2008Co-Authors: Michael L Fine, Robert F. ThorsonAbstract:Abstract Most passive acoustics studies focus on daily and seasonal timing and location of choruses of calling fish, particularly sciaenids. Because male Toadfish Opsanus spp. are stationary for extended periods, it is possible to extract detailed information about their calls and interactions, making them a powerful model for passive acoustics studies on commercially important species. Toadfishes of both sexes produce a short, pulsatile agonistic grunt, and males produce a “boatwhistle” advertisement call for male-male competition and to attract females. We identify unseen vocal individuals (oyster Toadfish O. tau and Gulf Toadfish O. beta) near a stationary hydrophone and describe call variability and changes over short- and long-term periods, source levels, call propagation, and directionality. Calls exhibit a directional pattern related to the heart-shaped swim bladder morphology, generating a maximal level behind the fish; grunt frequency spectra allow differentiation of individual callers over multi...
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Does muscle fatigue limit advertisement calling in the oyster Toadfish Opsanus tau
Animal Behaviour, 2008Co-Authors: Steve L. Mitchell, J. L. Poland, Michael L FineAbstract:Many sonic fishes appear to produce advertisement calls at a lower rate than insects, frogs and birds (song). Fish sonic muscles in many species rank among the fastest in vertebrates, suggesting that acoustic signalling is a costly activity. Surprisingly however, sound production in the oyster Toadfish Opsanus tau requires negligible oxygen consumption. Male Toadfish produce a long-duration tonal advertisement call, the boatwhistle, and both sexes produce short-duration agonistic grunt calls. The question of what limits the calling activity in fishes has not been addressed. We tested the hypothesis that calling in the oyster Toadfish is limited by fatigue of the sonic muscles by stimulating them intermittently at the most rapid rate evoked by playbacks of the courtship boatwhistle call (100 ms every 4 s at 200 Hz = 1.5 s stimulation/min) for 5 min and measured swimbladder movement, sound production and glycogen use. Muscles in both sexes showed almost complete fatigue by 5 min (7.5 s of stimulation), although rested control muscles contained over twice as much glycogen in males as in females. Glycogen use was similar in both sexes, but males used 10.8% of their glycogen and females used 23.2%. Glycogen would support muscle contraction at this rate for 15 min in males during mating call production. It appears that sound production in the oyster Toadfish is fatigue limited, which dictates a low rate of spontaneous calling that can be elevated for brief bursts of activity.
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Absence of a seasonal cycle in the sonic neuromuscular system of the oyster Toadfish
Journal of Fish Biology, 2000Co-Authors: M. S. Johnson, Joseph Feher, Tyler D Waybright, D.w. Matt, Michael L FineAbstract:No seasonal pattern was found in total swimbladder weight, sonic muscle weight, or spinal sonic motor nucleus neuron soma size of the oyster Toadfish Opsanus tau, indicating that additional nonsteroidal factors are also involved in the development of the Toadfish sonic neuromuscular system.
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comparison of sarcoplasmic reticulum capabilities in Toadfish opsanus tau sonic muscle and rat fast twitch muscle
Journal of Muscle Research and Cell Motility, 1998Co-Authors: Joseph Feher, Tyler D Waybright, Michael L FineAbstract:The sonic muscle of the oyster Toadfish, Opsanus tau, can produce unfused contractions at 300Hz. Electron microscopy shows a great abundance of the Sarcoplasmic reticulum (SR) in this muscle, but no functional characterization of the capabilities of this SR has been reported. We measured the oxalate-supported Ca2+ uptake rate and capacities of homogenates of Toadfish sonic muscle and rat extensor digitorum longus (EDL) muscle, and estimated the number of pump units by titration with thapsigargin, a high-affinity, specific inhibitor of the SR Ca-ATPase. The Ca2+ uptake rate averaged 70.9±9.5 mol min−1 per g tissue for the toad fish sonic muscle, and 73.5±3.7 mol min−1 g−1 for rat EDL. The capacity for Ca2+-oxalate uptake was 161±20 mol g−1 and 33±2 mol g−1 for Toadfish sonic muscle and rat EDL, respectively. Thus, the rates of Ca2+ uptake were similar in the two muscles, but the Toadfish sonic muscle had about five times the capacity of the rat EDL. The number of pumps as estimated by thapsigargin titration was 68±4 nmol of Ca-ATPase per g tissue in the Toadfish, and 42±5 nmol Ca-ATPase per g tissue in the rat EDL. The turnover number, defined as the Ca2+ uptake divided by the number of pumps, was 1065±150 min−1 for Toadfish and 1786±230 min−1 for rat EDL (p<0.05) at 37°C. The Ca2+ uptake rate of Toadfish sonic muscle at 22°C, a typical temperature for calling Toadfish, averaged 42±1% of its rate at 37°C. At these operating temperatures, the Toadfish SR is likely to be slower than the rat fast-twitch SR, yet the Toadfish sonic muscle supports more rapid contractions. One explanation for this is that the voluminous SR provides activator Ca2+ for contraction, but the abundant parvalbumin plays a major role in relaxation.
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Comparison of sarcoplasmic reticulum capabilities in Toadfish (Opsanus tau) sonic muscle and rat fast twitch muscle.
Journal of muscle research and cell motility, 1998Co-Authors: Joseph Feher, Tyler D Waybright, Michael L FineAbstract:The sonic muscle of the oyster Toadfish, Opsanus tau, can produce unfused contractions at 300Hz. Electron microscopy shows a great abundance of the Sarcoplasmic reticulum (SR) in this muscle, but no functional characterization of the capabilities of this SR has been reported. We measured the oxalate-supported Ca2+ uptake rate and capacities of homogenates of Toadfish sonic muscle and rat extensor digitorum longus (EDL) muscle, and estimated the number of pump units by titration with thapsigargin, a high-affinity, specific inhibitor of the SR Ca-ATPase. The Ca2+ uptake rate averaged 70.9±9.5 mol min−1 per g tissue for the toad fish sonic muscle, and 73.5±3.7 mol min−1 g−1 for rat EDL. The capacity for Ca2+-oxalate uptake was 161±20 mol g−1 and 33±2 mol g−1 for Toadfish sonic muscle and rat EDL, respectively. Thus, the rates of Ca2+ uptake were similar in the two muscles, but the Toadfish sonic muscle had about five times the capacity of the rat EDL. The number of pumps as estimated by thapsigargin titration was 68±4 nmol of Ca-ATPase per g tissue in the Toadfish, and 42±5 nmol Ca-ATPase per g tissue in the rat EDL. The turnover number, defined as the Ca2+ uptake divided by the number of pumps, was 1065±150 min−1 for Toadfish and 1786±230 min−1 for rat EDL (p
Danielle M Mcdonald - One of the best experts on this subject based on the ideXlab platform.
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evidence that gulf Toadfish use pulsatile urea excretion to communicate social status
Physiology & Behavior, 2020Co-Authors: Maria C. Cartolano, Elizabeth A Babcock, Danielle M McdonaldAbstract:Abstract Gulf Toadfish (Opsanus beta), a highly territorial marine teleost species, are believed to communicate through chemicals released across the gill during pulsatile urea excretion. While freshwater teleost and crustacean urinary signals have been shown to relay information about dominance to reduce physical aggression in future encounters, the use of chemical signals to convey social status in marine teleosts is understudied. Behavior and urea excretion patterns were monitored in pairs of male Toadfish during an initial agonistic encounter and in a 2nd encounter where a subset of pairs had their nares blocked to determine how olfaction, and thus chemical communication, play a role in establishing dominance. Anosmic Toadfish did not experience increases in aggressive behavior, unlike other species previously studied. However, behavior and the pattern of urea excretion were disrupted in anosmic pairs compared to control pairs. Specifically, control subordinate fish had an increase in their dominance index during the 2nd encounter, a response that anosmic subordinate fish did not experience suggesting that without the ability to smell, subordinate fish cannot recognize their opponent and assess their fighting ability and have a reduced chance of winning. These anosmic subordinate fish also had an increase in pulse frequency, perhaps reflecting an increased effort in communication of status. Future research is needed to conclude if peaks in agonistic behavior are coordinated around the time of urea pules. However, the observed changes in behavior and pulsatile urea excretion due to anosmia in the present study provide evidence that Toadfish use pulsatile urea excretion to release signals for chemical communication during agonistic encounters.
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a waterborne chemical cue from gulf Toadfish opsanus beta prompts pulsatile urea excretion in conspecifics
Physiology & Behavior, 2017Co-Authors: Jeremy Fulton, Christophe M R Lemoine, Carol Bucking, Kevin V Brix, Patrick J Walsh, Danielle M McdonaldAbstract:The Gulf Toadfish (Opsanus beta) has a fully functional ornithine urea cycle (O-UC) that allows it to excrete nitrogenous waste in the form of urea. Interestingly, urea is excreted in a pulse across the gill that lasts 1-3h and occurs once or twice a day. Both the stress hormone, cortisol, and the neurotransmitter, serotonin (5-HT) are involved in the control of pulsatile urea excretion. This and other evidence suggests that urea pulsing may be linked to Toadfish social behavior. The hypothesis of the present study was that Toadfish urea pulses can be triggered by waterborne chemical cues from conspecifics. Our findings indicate that exposure to seawater that held a donor conspecific for up to 48h (pre-conditioned seawater; PC-SW) induced a urea pulse within 7h in naive conspecifics compared to a pulse latency of 20h when exposed to seawater alone. Factors such as PC-SW intensity and donor body mass influenced the pulse latency response of naive conspecifics. Fractionation and heat treatment of PC-SW to narrow possible signal candidates revealed that the active chemical was both water-soluble and heat-stable. Fish exposed to urea, cortisol or 5-HT in seawater did not have a pulse latency that was significantly different than seawater alone; however, ammonia, perhaps in the form of NH4Cl, was found to be a factor in the pulse latency response of Toadfish to PC-SW and could be one component of a multi-component cue used for chemical communication in Toadfish. Further studies are needed to fully identify the chemical cue as well as determine its adaptive significance in this marine teleost fish.
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cortisol mediated downregulation of the serotonin 1a receptor subtype in the gulf Toadfish opsanus beta
Comparative Biochemistry and Physiology A-molecular & Integrative Physiology, 2013Co-Authors: Lea R. Medeiros, Danielle M McdonaldAbstract:In both mammals and teleost fish, serotonin stimulates cortisol secretion via the 5-HT1A receptor. Additionally, a negative feedback loop exists in mammals whereby increased circulating levels of cortisol inhibit 5-HT1A receptor activity. To investigate the possibility of such a feedback mechanism in teleosts, plasma cortisol levels and signaling in Gulf Toadfish (Opsanus beta) were manipulated and the role of cortisol in the control of 5-HT1A evaluated. Despite a significant 4-fold increase in plasma [cortisol], crowded Toadfish expressed similar amounts of 5-HT1A mRNA transcript as uncrowded Toadfish; whereas, cortisol-implanted fish possessed 41.8% less 5-HT1A mRNA transcript compared to vehicle-implanted controls. This cortisol effect appeared to be reversed in RU486-injected fish, which blocks glucocorticoid receptors, as these fish expressed nearly twice as much 5-HT1A receptor transcript as the vehicle-injected fish despite significantly elevated cortisol levels. The binding affinity for the 5-HT1A receptor in the brain did not vary between any groups; however, maximum binding was significantly higher in uncrowded Toadfish compared to crowded, and the same significant difference was observed between the maximum binding of vehicle and cortisol-implanted fish. The opposite trend was seen in RU486-injected and vehicle-injected fish, with RU486-injected fish having significantly higher maximal binding compared to vehicle-injected controls. Injection with the 5-HT1A receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin revealed an inhibition of cortisol secretion that was independent of 5-HT1A transcript and protein binding. These results suggest that cortisol plays a role in regulating the 5-HT1A receptor via GR-mediated pathways; however, further study is necessary to elucidate how and where this inhibition is mediated.
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immunohistochemical localization of urea and ammonia transporters in two confamilial fish species the ureotelic gulf Toadfish opsanus beta and the ammoniotelic plainfin midshipman porichthys notatus
Cell and Tissue Research, 2013Co-Authors: Carol Bucking, Danielle M Mcdonald, Craig P. Smith, Susan L Edwards, Paul Tickle, Patrick J WalshAbstract:This study aims to illustrate potential transport mechanisms behind the divergent approaches to nitrogen excretion seen in the ureotelic Toadfish (Opsanus beta) and the ammoniotelic plainfin midshipman (Porichthys notatus). Specifically, we wish to confirm the expression of a urea transporter (UT), which is found in the gill of the Toadfish and which is responsible for the unique “pulsing” nature of urea excretion and to localize the transporter within specific gill cells and at specific cellular locations. Additionally, the localization of ammonia transporters (Rhesus glycoproteins; Rhs) within the gill of both the Toadfish and midshipman was explored. Toadfish UT (tUT) was found within Na+-K+-ATPase (NKA)-enriched cells, i.e., ionocytes (probably mitochondria-rich cells), especially along the basolateral membrane and potentially on the apical membrane. In contrast, midshipman UT (pnUT) immunoreactivity did not colocalize with NKA immunoreactivity and was not found along the filaments but instead within the lamellae. The cellular location of Rh proteins was also dissimilar between the two fish species. In Toadfish gills, the Rh isoform Rhcg1 was expressed in both NKA-reactive cells and non-reactive cells, whereas Rhbg and Rhcg2 were only expressed in the latter. In contrast, Rhbg, Rhcg1 and Rhcg2 were expressed in both NKA-reactive and non-reactive cells of midshipman gills. In an additional transport epithelium, namely the intestine, the expression of both UTs and Rhs was similar between the two species, with only subtle differences being observed.
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elevated cortisol inhibits adrenocorticotropic hormone and serotonin stimulated cortisol secretion from the interrenal cells of the gulf Toadfish opsanus beta
General and Comparative Endocrinology, 2012Co-Authors: Lea R. Medeiros, Danielle M McdonaldAbstract:Abstract Stimulation of the Toadfish 5-HT1A receptor by serotonin (5-hydroxytryptamine; 5-HT) or 8-OH-DPAT, a 5-HT1A receptor agonist, results in a significant elevation in plasma cortisol. Conversely, chronic elevation of plasma cortisol has been shown to decrease brain 5-HT1A receptor mRNA and protein levels via the glucocorticoid receptor (GR); however, there appears to be a disconnect between brain levels of the receptor and cortisol release. We hypothesized that elevated plasma cortisol would inhibit both adrenocorticotropic hormone (ACTH)- and 5-HT-stimulated cortisol release from the interrenal cells of Gulf Toadfish, that ACTH sensitivity would not be GR-mediated and 5-HT-stimulated cortisol release would not be via the 5-HT1A receptor. To test these hypotheses, interrenal cells from uncrowded, crowded, vehicle-, and cortisol-implanted Toadfish were incubated with either ACTH, 5-HT or 5-HT receptor agonists, and cortisol secretion was measured. Incubation with ACTH or 5-HT resulted in a stimulation of cortisol secretion in uncrowded Toadfish. Cortisol secretion in response to ACTH was not affected in crowded fish; however, interrenal cells from cortisol-implanted Toadfish secreted significantly less cortisol than controls, a response that was not reversed upon treatment with the GR antagonist RU486. 5-HT-stimulated cortisol release was significantly lower from both crowded and cortisol-implanted Toadfish interrenal cells compared to controls. Incubation with either a 5-HT4 or a 5-HT2 receptor agonist significantly stimulated cortisol secretion; however, incubation with 8-OH-DPAT did not, suggesting that the 5-HT1A receptor is not a mediator of cortisol release at the level of the interrenal cells. Combined, these results explain in part the disconnect between brain 5-HT1A levels and cortisol secretion.
Allen F. Mensinger - One of the best experts on this subject based on the ideXlab platform.
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The effect of biological and anthropogenic sound on the auditory sensitivity of oyster Toadfish, Opsanus tau
Journal of Comparative Physiology A, 2019Co-Authors: Loranzie S. Rogers, Rosalyn L. Putland, Allen F. MensingerAbstract:Many aquatic organisms use vocalizations for reproductive behavior; therefore, disruption of their soundscape could adversely affect their life history. Male oyster Toadfish ( Opsanus tau ) establish nests in shallow waters during spring and attract female fish with boatwhistle vocalizations. Males exhibit high nest fidelity, making them susceptible to anthropogenic sound in coastal waters, which could mask their vocalizations and/or reduce auditory sensitivity levels. Additionally, the effect of self-generated boatwhistles on Toadfish auditory sensitivity has yet to be addressed. To investigate the effect of sound exposure on Toadfish auditory sensitivity, sound pressure and particle acceleration sensitivity curves were determined using auditory evoked potentials before and after (0-, 1-, 3-, 6- and 9-day) exposure to 1- or 12-h of continuous playbacks to ship engine sound or conspecific vocalization. Exposure to boatwhistles had no effect on auditory sensitivity. However, exposure to anthropogenic sound caused significant decreases in auditory sensitivity for at least 3 days, with shifts up to 8 dB SPL and 20 dB SPL immediately following 1- and 12-h anthropogenic exposure, respectively. Understanding the effect of self-generated and anthropogenic sound exposure on auditory sensitivity provides an insight into how soundscapes affect acoustic communication.
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long term pam to investigate temporal and anthropogenic effects on oyster Toadfish opsanus tau mating vocalizations
Journal of the Acoustical Society of America, 2019Co-Authors: Rosalyn L. Putland, Allen F. Mensinger, Jacey C Van Wert, Alayna MackiewiczAbstract:For the oyster Toadfish, Opsanus tau, vocal communication and sound detection are critical for reproductive success, however, little is known about how they respond to changes in their acoustic environment. Passive acoustic monitoring was conducted in Eel Pond, MA, USA in the summer months (2017–2019) to investigate vocalization patterns of the resident population and the effect of anthropogenic sound. Male Toadfish produce mating vocalizations that are characterized by an initial broadband segment (30–50 ms, 100–1000 Hz) and a longer tonal section (200–650 ms, 100–500 Hz). The pulse repetition rate of the tonal section was significantly related to ambient water temperature during hourly and weekly monitoring. Time difference of arrivals were also used to pinpoint the location of Toadfish nests and linked to ambient and anthropogenic sound-maps to understand exposure levels for individual fish. Significantly less vocalizations were detected following exposure to vessel sound (100–12 000 Hz, source level 130 dB re 1 μPa), suggesting individuals changed their vocal behavior in response to anthropogenic activity. Both environmental and the presence of vessel sound influence the acoustic behaviour of Toadfish, which could lead to a reduction in communication space, mate attraction and detection.For the oyster Toadfish, Opsanus tau, vocal communication and sound detection are critical for reproductive success, however, little is known about how they respond to changes in their acoustic environment. Passive acoustic monitoring was conducted in Eel Pond, MA, USA in the summer months (2017–2019) to investigate vocalization patterns of the resident population and the effect of anthropogenic sound. Male Toadfish produce mating vocalizations that are characterized by an initial broadband segment (30–50 ms, 100–1000 Hz) and a longer tonal section (200–650 ms, 100–500 Hz). The pulse repetition rate of the tonal section was significantly related to ambient water temperature during hourly and weekly monitoring. Time difference of arrivals were also used to pinpoint the location of Toadfish nests and linked to ambient and anthropogenic sound-maps to understand exposure levels for individual fish. Significantly less vocalizations were detected following exposure to vessel sound (100–12 000 Hz, source level 1...
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Seasonal and Daily Patterns of the Mating Calls of the Oyster Toadfish, Opsanus tau.
The Biological bulletin, 2019Co-Authors: Jacey C Van Wert, Allen F. MensingerAbstract:AbstractAcoustic communication is vital across many taxa for mating behavior, defense, and social interactions. Male oyster Toadfish, Opsanus tau, produce courtship calls, or “boatwhistles,” characterized by an initial broadband segment (30–50 ms) and a longer tone-like second part (200–650 ms) during mating season. Male calls were monitored continuously with an in situ SoundTrap hydrophone that was deployed in Eel Pond, Woods Hole, Massachusetts, during the 2015 mating season. At least 10 vocalizing males were positively identified by their unique acoustic signatures. This resident population was tracked throughout the season, with several individuals tracked for extended periods of time (72 hours). Toadfish began calling in mid-May when water temperature reached 14.6 °C with these early-season “precursor” boatwhistles that were shorter in duration and contained less distinct tonal segments compared to calls later in the season. The resident Toadfish stopped calling in mid-August, when water temperature ...
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Using passive acoustics to localize vocalizing oyster Toadfish (Opsanus tau)
The Journal of the Acoustical Society of America, 2018Co-Authors: Rosalyn L. Putland, Alayna Mackiewicz, Allen F. MensingerAbstract:Identifying where fish inhabit is a fundamentally important topic in ecology and acoustic tools can help management to prioritize acoustically sensitive times and areas. In this study, passive acoustic monitoring is presented as a viable tool for monitoring the positions of vocalizing fish species, like the oyster Toadfish. Time of arrival differences (TOADs) of sound recordings on a four-hydrophone array were used to pinpoint the location of male oyster Toadfish, Opsanus tau, a sedentary fish that produces boatwhistle vocalizations to attract females. Coupling the TOAD method with cross correlation of the different boatwhistles, individual Toadfish were mapped during three-hour periods at dawn, midday, dusk, and midnight to examine the relationship between temporal and spatial trends. Seven individual males were identified within 24.2 m of the hydrophone array and up to 18.2 m of the other individuals. The advantages and disadvantages of using the TOAD method to localize individual fish will be discussed. Additionally, preliminary data on how individual Toadfish respond to the anthropogenic sound of passing motorized vessels as well as conspecific boatwhistles will be introduced.Identifying where fish inhabit is a fundamentally important topic in ecology and acoustic tools can help management to prioritize acoustically sensitive times and areas. In this study, passive acoustic monitoring is presented as a viable tool for monitoring the positions of vocalizing fish species, like the oyster Toadfish. Time of arrival differences (TOADs) of sound recordings on a four-hydrophone array were used to pinpoint the location of male oyster Toadfish, Opsanus tau, a sedentary fish that produces boatwhistle vocalizations to attract females. Coupling the TOAD method with cross correlation of the different boatwhistles, individual Toadfish were mapped during three-hour periods at dawn, midday, dusk, and midnight to examine the relationship between temporal and spatial trends. Seven individual males were identified within 24.2 m of the hydrophone array and up to 18.2 m of the other individuals. The advantages and disadvantages of using the TOAD method to localize individual fish will be discussed...
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an implantable two axis micromanipulator made with a 3d printer for recording neural activity in free swimming fish
Journal of Neuroscience Methods, 2017Co-Authors: Loranzie S. Rogers, Allen F. Mensinger, Jacey C Van WertAbstract:Abstract Background Chronically implanted electrodes allow monitoring neural activity from free moving animals. While a wide variety of implanted headstages, microdrives and electrodes exist for terrestrial animals, few have been developed for use with aquatic animals. New method A two axis micromanipulator was fabricated with a Formlabs 3D printer for implanting electrodes into free-swimming oyster Toadfish ( Opsanus tau ). The five piece manipulator consisted of a base, body, electrode holder, manual screw drive and locking nut. The manipulator measured approximately 25 × 20 × 30 mm (l × w × h) and weighed 5.28 g after hand assembly. Results Microwire electrodes were inserted successfully with the manipulator to record high fidelity signals from the anterior lateral line nerve of the Toadfish. Comparison with existing method(s) The micromanipulator allowed the chronically implanted electrodes to be repositioned numerous times to record from multiple sites and extended successful recording time in the Toadfish by several days. Conclusions Three dimensional printing allowed an inexpensive (
