scholarly journals Hydrogen sulfide exposure reduces thermal set point in zebrafish

2020 ◽  
Vol 7 (11) ◽  
pp. 200416
Author(s):  
Dimitri A. Skandalis ◽  
Cheryl D. Dobell ◽  
Joshua C. Shaw ◽  
Glenn J. Tattersall
Keyword(s):  
Hydrogen Sulfide ◽  
Physiological State ◽  
Metabolic Stress ◽  
Passive Components ◽  
Set Point ◽  
Metabolic Physiology ◽  
Different Temperatures ◽  
Preferred Temperatures ◽  
Environmental Toxin ◽  
Preferred Body Temperature

Behavioural flexibility allows ectotherms to exploit the environment to govern their metabolic physiology, including in response to environmental stress. Hydrogen sulfide (H 2 S) is a widespread environmental toxin that can lethally inhibit metabolism. However, H 2 S can also alter behaviour and physiology, including a hypothesized induction of hibernation-like states characterized by downward shifts of the innate thermal set point (anapyrexia). Support for this hypothesis has proved controversial because it is difficult to isolate active and passive components of thermoregulation, especially in animals with high resting metabolic heat production. Here, we directly test this hypothesis by leveraging the natural behavioural thermoregulatory drive of fish to move between environments of different temperatures in accordance with their current physiological state and thermal preference. We observed a decrease in adult zebrafish ( Danio rerio ) preferred body temperature with exposure to 0.02% H 2 S, which we interpret as a shift in the thermal set point. Individuals exhibited consistent differences in shuttling behaviour and preferred temperatures, which were reduced by a constant temperature magnitude during H 2 S exposure. Seeking lower temperatures alleviated H 2 S-induced metabolic stress, as measured by reduced rates of aquatic surface respiration. Our findings highlight the interactions between individual variation and sublethal impacts of environmental toxins on behaviour.

scholarly journals Hydrogen sulfide exposure reduces thermal set point in zebrafish

2020 ◽  
Author(s):  
Dimitri A. Skandalis ◽  
Cheryl D. Dobell ◽  
Joshua C. Shaw ◽  
Glenn J. Tattersall
Keyword(s):  
Hydrogen Sulfide ◽  
Physiological State ◽  
Metabolic Stress ◽  
Passive Components ◽  
Metabolic Heat ◽  
Metabolic Physiology ◽  
Different Temperatures ◽  
Preferred Temperatures ◽  
Environmental Toxin ◽  
Preferred Body Temperature

AbstractBehavioural flexibility allows ectotherms to exploit the environment to govern their metabolic physiology, including in response to environmental stress. Hydrogen sulfide (H2S) is a widespread environmental toxin that can lethally inhibit metabolism. However, H2S can also alter behaviour and physiology, including a hypothesised induction of hibernation-like states characterised by downward shifts of the innate thermal setpoint (anapyrexia). Support for this hypothesis has proved controversial because it is difficult to isolate active and passive components of thermoregulation, especially in animals with high resting metabolic heat production. Here, we directly test this hypothesis by leveraging the natural behavioural thermoregulatory drive of fish to move between environments of different temperatures in accordance with their current physiological state and thermal preference. We observed a decrease in adult zebrafish (Danio rerio) preferred body temperature with exposure to 0.02% H2S, which we interpret as a shift in thermal setpoint. Individuals exhibited consistent differences in shuttling behaviour and preferred temperatures, which were reduced by a constant temperature magnitude during H2S exposure. Seeking lower temperatures alleviated H2S-induced metabolic stress, as measured by reduced rates of aquatic surface respiration rate. Our findings highlight the interactions between individual variation and sublethal impacts of environmental toxins on behaviour.

Set-Point Displacement for Behavioural Thermoregulation in Anorexia Nervosa

1982 ◽  
Vol 62 (6) ◽  
pp. 677-682 ◽  
Author(s):  
P. Luck ◽  
A. Wakeling
Keyword(s):  
Anorexia Nervosa ◽  
Control Group ◽  
Behavioural Thermoregulation ◽  
Deep Body Temperature ◽  
Set Point ◽  
Control Subjects ◽  
Preferred Temperatures ◽  
High Stimulus ◽  
Thermal Preferences ◽  
Patients Experience

1. The temperatures of thermal stimuli which evoked a feeling of maximal pleasantness upon contact with the hands of 14 malnourished patients with anorexia nervosa and 19 control subjects have been determined. A uniform skin temperature of 35°C for all individuals studied was achieved by immersion of the subjects and patients in water at that temperature. Core temperatures of the anorexic patients were similar to those of the control subjects, but six of the patients preferred temperatures that were significantly higher than those of the control subjects. The thermal preferences of the remainder of the patients were similar to those of the control subjects. 2. The abnormally high thermal preferences of some of the anorexic patients could not be attributed to abnormal thyroid status, since values for serum free thyroxine measured in this group were similar to those obtained for the remaining patients. The abnormal responses persisted after there had been a substantial gain in the patients'weight and did not therefore appear to be directly due to malnutrition. 3. Elevation of deep body temperature produced an expected shift in preference towards lower stimulus temperatures in a sample of subjects from the control group, and in the patients who had initially preferred temperatures within the range of the controls. In the patients who had initially preferred abnormally high stimulus temperatures, however, hyperthermia produced little change in thermal preference. 4. It is suggested that an elevation in the set-point temperature for behavioural thermoregulation can occur in some patients with anorexia nervosa, and that this displacement-5-contribute to the distressing sense of cold which some patients experience.

scholarly journals Selective gas detection using Mn3O4/WO3 composites as a sensing layer

2019 ◽  
Vol 10 ◽  
pp. 1423-1433 ◽  
Author(s):  
Yongjiao Sun ◽  
Zhichao Yu ◽  
Wenda Wang ◽  
Pengwei Li ◽  
Gang Li ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Hydrogen Sulfide ◽  
Gas Sensing ◽  
Gas Detection ◽  
Facile Hydrothermal Method ◽  
Potential Applications ◽  
Different Temperatures ◽  
Different Gases ◽  
Sensing Performance ◽  
Mn Concentrations

Pure WO3 sensors and Mn3O4/WO3 composite sensors with different Mn concentrations (1 atom %, 3 atom % and 5 atom %) were successfully prepared through a facile hydrothermal method. As gas sensing materials, their sensing performance at different temperatures was systematically investigated for gas detection. The devices displayed different sensing responses toward different gases at specific temperatures. The gas sensing performance of Mn3O4/WO3 composites (especially at 3 atom % Mn) were far improved compared to sensors based on pure WO3, where the improvement is related to the heterojunction formed between the two metal oxides. The sensor based on the Mn3O4/WO3 composite with 3 atom % Mn showed a high selective response to hydrogen sulfide (H2S), ammonia (NH3) and carbon monoxide (CO) at working temperatures of 90 °C, 150 °C and 210 °C, respectively. The demonstrated superior selectivity opens the door for potential applications in gas recognition and detection.

Fibroblast growth factor-21 improves insulin action in non-lactating ewes

2022 ◽  
Author(s):  
Cassandra L Lamb ◽  
Sarah L. Giesy ◽  
Molly M McGuckin ◽  
James W. Perfield ◽  
Anthony Butterfield ◽  
...  
Keyword(s):  
Growth Factor ◽  
Fibroblast Growth Factor ◽  
Insulin Action ◽  
Physiological State ◽  
Fibroblast Growth Factor 21 ◽  
Target Tissue ◽  
Fibroblast Growth ◽  
Entire Treatment Period ◽  
Set Point ◽  
Improve Insulin Action

During metabolically demanding physiological states, ruminants and other mammals coordinate nutrient use among tissues by varying the set point of insulin action. This set point is regulated in part by metabolic hormones with some antagonizing (e.g., growth hormone and TNFa) and others potentiating (e.g., adiponectin) insulin action. Fibroblast growth factor-21 (FGF21) was recently identified as a sensitizing hormone in rodent and primate models of defective insulin action. FGF21 administration, however, failed to improve insulin action in dairy cows during the naturally occurring insulin resistance of lactation, raising the possibility that ruminants as a class of animals or lactation as a physiological state are unresponsive to FGF21. To start addressing this question, we asked whether FGF21 could improve insulin action in non-lactating ewes. Gene expression studies showed that the ovine FGF21 system resembles that of other species, with liver as the major site of FGF21 expression and adipose tissue as a target tissue based on high expression of the FGF21 receptor complex and activation of p44/42 ERK1/2 following exogenous FGF21 administration. FGF21 treatment for 13 days reduced plasma glucose and insulin over the entire treatment period and improved glucose disposal during a glucose tolerance test. FGF21 increased plasma adiponectin by day 3 of treatment but had no effect on the plasma concentrations of total, C16:0-, or C18:0-ceramide. Overall, these data confirm that the insulin-sensitizing effects of FGF21 are conserved in ruminants and raise the possibility that lactation is an FGF21 resistant state.

Indomethacin impairs LPS-induced behavioral fever in toads

2002 ◽  
Vol 93 (2) ◽  
pp. 512-516 ◽  
Author(s):  
K. C. Bicego ◽  
A. A. Steiner ◽  
J. Antunes-Rodrigues ◽  
L. G. S. Branco
Keyword(s):  
Body Temperature ◽  
Thermal Gradient ◽  
Behavioral Thermoregulation ◽  
Cyclooxygenase Inhibitor ◽  
Set Point ◽  
Behavioral Fever ◽  
Preferred Body Temperature ◽  
Baseline Values ◽  
Toad Bufo

We tested the hypothesis that PGs mediate lipopolysaccharide (LPS)-induced behavioral fever in the toad Bufo paracnemis. Measurements of preferred body temperature (Tb) were performed with a thermal gradient. Toads were injected intraperitoneally with the cyclooxygenase inhibitor indomethacin (5 mg/kg), which inhibits PG biosynthesis, or its vehicle (Tris) followed 30 min later by LPS (0.2 and 2 mg/kg) into the lymph sac. LPS at the dose of 0.2 mg/kg caused a significant increase in Tb from 7 to 10 h after injection, and then Tb returned toward baseline values. LPS at the dose of 2 mg/kg produced a different pattern of response, with a longer latency to the onset of fever (10th h) and a longer duration (until the end of the experiment at the 15th h). Tris significantly attenuated the fever induced by LPS at 0.2 mg/kg, but not at 2 mg/kg. Moreover, indomethacin completely blocked the fever evoked by LPS (2 mg/kg). These results indicate that the behavioral fever induced by LPS in toads requires the activation of the COX pathway, suggesting that the involvement of PG in fever has an ancient phylogenetic history and that endogenous PGs raise the thermoregulatory set point to produce fever, because behavioral thermoregulation seems to be related to changes in the thermoregulatory set point.

Metabolic physiology of the southeastern USA crayfish, Cambarus latimanus (LeConte), in response to different temperatures

2015 ◽  
Vol 21 (1) ◽  
pp. 171-177
Author(s):  
Mark Meade ◽  
Lindsay White ◽  
Rahim Zettili ◽  
Megan Meade ◽  
Saad Almani ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Energy Budgets ◽  
Intermittent Flow ◽  
Potential Growth ◽  
Energy Demands ◽  
Acclimation Period ◽  
Metabolic Physiology ◽  
Consumption Rates ◽  
Different Temperatures ◽  
Q10 Values

Abstract Variable crayfish, Cambarus latimanus (LeConte), were collected and acclimated to four temperatures, 15, 20, 25, and 30°C. Following a two-week acclimation period, mean standard metabolic rates (SMR), as determined using oxygen consumption rates, were measured using an intermittent-flow, closed-loop respirometer. For ~10g mean weight C. latimanus, mean weight specific oxygen consumption rates (MO2) at 15, 20, 25, and 30°C were 73.4 ± 0.18, 81.6 ± 0.10, 103 ± 0.11, and 205 ± 0.12 mg O2·kg-1·h-1 (±SE), respectively. Calculated Q10 values of 1.25, 1.61, and 3.92 for the change in metabolic rate from 15 – 20°C, 20 – 25°C, and 25 – 30°C suggest the crayfish were responding normally to temperature increases and were metabolically stressed when temperatures increased above 25°C. Daily caloric energy budgets of 58 (15°C), 65 (20°C), 82 (25°C), and 164 (30°C) calories·day-1 were estimated for crayfishes using SMR data and suggested that crayfish standard (resting) energy requirements nearly tripled when acclimated to 15 versus 30°C. Overall, these data suggest that increased temperatures have substantial effects on C. latimanus energy demands which may reduce potential growth and reproduction.

Lymphocyte Chalone from Calf Thymus: Problems of Large Scale Extraction and Assay

1981 ◽  
Vol 36 (7-8) ◽  
pp. 568-571
Author(s):  
Reinhard Maschler ◽  
H. Rainer Maurer
Keyword(s):  
Human Blood ◽  
Lymphocyte Proliferation ◽  
Large Scale ◽  
Physiological State ◽  
Slow Freezing ◽  
Blood Lymphocytes ◽  
Calf Thymus ◽  
Quick Freezing ◽  
Apparent Decrease ◽  
Different Temperatures

Abstract Large scale extraction and assay of the lymphocyte chalone (LC), the natural lymphocyte proliferation inhibitor, require optimized, reproducible and standardizable methods. To this end we compared the effects on LC yield of storing thymus at different temperatures after collection from calves: Both quick freezing on solid CO2 and slow freezing at -5 0 °C led to a 30% loss of LC yield relative to that from unfrozen tissue kept at 0°C . Moreover we found that the apparent decrease or total loss of LC activity upon storage of a purified LC fraction may result from an occasional lack of LC-responsiveness of human blood lymphocytes depending on the donor's physiological state, in spite of normal PHA reactivity. This suggested the use of LC-responsive, cryopreserved lymphocytes, the advantages of which are documented and discussed in detail.

scholarly journals Microbial conversion of inorganic carbon to dimethyl sulfide in anoxic lake sediment (Plußsee, Germany)

2010 ◽  
Vol 7 (2) ◽  
pp. 2569-2599 ◽  
Author(s):  
Y.-S. Lin ◽  
V. B. Heuer ◽  
T. G. Ferdelman ◽  
K.-U. Hinrichs
Keyword(s):  
Hydrogen Sulfide ◽  
Inorganic Carbon ◽  
Dimethyl Sulfide ◽  
Dissolved Inorganic Carbon ◽  
Syringic Acid ◽  
Sulfur Cycle ◽  
Microbial Conversion ◽  
Methyl Group ◽  
Anoxic Environments ◽  
Different Temperatures

Abstract. In anoxic environments, volatile methylated sulfides including methanethiol (MT) and dimethyl sulfide (DMS) link the pools of inorganic and organic carbon with the sulfur cycle. However, direct formation of methylated sulfides from reduction of dissolved inorganic carbon has previously not been demonstrated. During examination of the hydrogenotrophic microbial activity at different temperatures in the anoxic sediment from Lake Plußsee, DMS formation was detected at 55 °C and was enhanced when bicarbonate was supplemented. Addition of both bicarbonate and H2 resulted in the strongest stimulation of DMS production, and MT levels declined slightly. Addition of methyl-group donors such as methanol and syringic acid or methyl-group acceptors such as hydrogen sulfide did not enhance further accumulation of DMS and MT. The addition of 2-bromoethanesulfonate inhibited DMS formation and caused a slight MT accumulation. MT and DMS had average δ13C values of −55‰ and −62‰, respectively. Labeling with NaH13CO3 showed that incorporation of bicarbonate into DMS occurred through methylation of MT. H235S labeling demonstrated a microbially-mediated, but slow, process of hydrogen sulfide methylation that accounted for <10% of the accumulation rates of DMS. Our data suggest: (1) methanogens are involved in DMS formation from bicarbonate, and (2) the major source of the 13C-depleted MT is neither bicarbonate nor methoxylated aromatic compounds. Other possibilities for isotopically light MT, such as demethylation of 13C-depleted DMS or other organic precursors such as methionine, are discussed. This DMS-forming pathway may be relevant for anoxic environments, such as hydrothermally influenced sediments and fluids and sulfate-methane transition zones in marine sediments.

Experimental investigation and modelling of the effect of sulfate on anaerobic biodegradation processes in municipal solid waste

2003 ◽  
Vol 48 (4) ◽  
pp. 221-227 ◽  
Author(s):  
N. Mora-Naranjo ◽  
C. Alamar-Provecho ◽  
J. Meima ◽  
A. Haarstrick ◽  
D.C. Hempel
Keyword(s):  
Hydrogen Sulfide ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Anaerobic Biodegradation ◽  
Inhibitory Effect ◽  
Experimental Investigations ◽  
Methane Formation ◽  
Inhibition Effect ◽  
Different Temperatures ◽  
Good Agreement

The experimental investigations have been carried out in two parts. First, the biodegradation of the organic compounds in the municipal solid waste has been investigated with focus on different sulfate concentrations influencing the methane formation. Second, the inhibition effect of hydrogen sulfide in solution (H2Saq) on the acetate, and methane formation, respectively, has been studied at different pH and temperature values. In solution the equilibrium of hydrogen sulfide (H2S(aq)) and the hydrogen sulfide anion (HS-(aq)) mainly depends on pH. At pH 6.3 the favoured species is H2S(aq) whereas at pH 7.7 the HS-(aq) species is favoured. Additionally, the experiments have been carried out at two different temperatures (35°C and 55°C). According to the acetate and methane formation the H2S(aq) species is observed to have an inhibitory effect. All simulations based on a biodegradation model represented are in good agreement with the experimental data obtained.

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