scholarly journals Resilience of cardiac performance in Antarctic notothenioid fishes in a warming climate

2021 ◽  
Vol 224 (10) ◽  
Author(s):  
Kristin M. O'Brien ◽  
William Joyce ◽  
Elizabeth L. Crockett ◽  
Michael Axelsson ◽  
Stuart Egginton ◽  
...  
Keyword(s):  
Cardiac Failure ◽  
Thermal Tolerance ◽  
Anthropogenic Activities ◽  
Membrane Integrity ◽  
Cardiac Performance ◽  
Homeoviscous Adaptation ◽  
In Captivity ◽  
Microsomal Membranes ◽  
Warm Acclimation ◽  
Lower Temperature

ABSTRACT Warming in the region of the Western Antarctic Peninsula is occurring at an unprecedented rate, which may threaten the survival of Antarctic notothenioid fishes. Herein, we review studies characterizing thermal tolerance and cardiac performance in notothenioids – a group that includes both red-blooded species and the white-blooded, haemoglobinless icefishes – as well as the relevant biochemistry associated with cardiac failure during an acute temperature ramp. Because icefishes do not feed in captivity, making long-term acclimation studies unfeasible, we focus only on the responses of red-blooded notothenioids to warm acclimation. With acute warming, hearts of the white-blooded icefish Chaenocephalus aceratus display persistent arrhythmia at a lower temperature (8°C) compared with those of the red-blooded Notothenia coriiceps (14°C). When compared with the icefish, the enhanced cardiac performance of N. coriiceps during warming is associated with greater aerobic capacity, higher ATP levels, less oxidative damage and enhanced membrane integrity. Cardiac performance can be improved in N. coriiceps with warm acclimation to 5°C for 6–9 weeks, accompanied by an increase in the temperature at which cardiac failure occurs. Also, both cardiac mitochondrial and microsomal membranes are remodelled in response to warm acclimation in N. coriiceps, displaying homeoviscous adaptation. Overall, cardiac performance in N. coriiceps is malleable and resilient to warming, yet thermal tolerance and plasticity vary among different species of notothenioid fishes; disruptions to the Antarctic ecosystem driven by climate warming and other anthropogenic activities endanger the survival of notothenioids, warranting greater protection afforded by an expansion of marine protected areas.

scholarly journals CONTROLLED PROTEOLYSIS OF NASCENT POLYPEPTIDES IN RAT LIVER CELL FRACTIONS

1970 ◽  
Vol 45 (1) ◽  
pp. 146-157 ◽  
Author(s):  
D. D. Sabatini ◽  
G. Blobel
Keyword(s):  
Amino Acid ◽  
Messenger Rna ◽  
Close Association ◽  
Membrane Integrity ◽  
Sucrose Density Gradient ◽  
Electron Microscopic ◽  
Microsomal Membranes ◽  
Membrane Bound ◽  
Cell Fractions

Rough microsomes were incubated in an in vitro amino acid-incorporating system for labeling the nascent polypeptide chains on the membrane-bound ribosomes. Sucrose density gradient analysis showed that ribosomes did not detach from the membranes during incorporation in vitro. Trypsin and chymotrypsin treatment of microsomes at 0° led to the detachment of ribosomes from the membranes; furthermore, trypsin produced the dissociation of released, messenger RNA-free ribosomes into subunits. Electron microscopic observations indicated that the membranes remained as closed vesicles. In contrast to the situation with free polysomes, nascent chains contained in rough microsomes were extensively protected from proteolytic attach. By separating the microsomal membranes from the released subunits after proteolysis, it was found that nascent chains are split into two size classes of fragments when the ribosomes are detached. These were shown by column chromatography on Sephadex G-50 to be: (a) small (39 amino acid residues) ribosome-associated fragments and (b) a mixture of larger membrane-associated fragments excluded from the column. The small fragments correspond to the carboxy-terminal segments which are protected by the large subunits of free polysomes. The larger fragments associated with the microsomal membranes depend for their protection on membrane integrity. These fragments are completely digested if the microsomes are subjected to proteolysis in the presence of detergents. These results indicate that when the nascent polypeptides growing in the large subunits of membrane-bound ribosomes emerge from the ribosomes they enter directly into a close association with the microsomal membrane.

scholarly journals Development of Sperm Cryopreservation Protocols for Sharks and Rays: New Tools for Elasmobranch Conservation

2021 ◽  
Vol 8 ◽  
Author(s):  
Pablo García-Salinas ◽  
Victor Gallego ◽  
Juan F. Asturiano
Keyword(s):  
Sperm Quality ◽  
Membrane Integrity ◽  
Egg Yolk ◽  
Ex Situ ◽  
Conservation Strategies ◽  
Sperm Cryopreservation ◽  
In Captivity ◽  
Reproductive Techniques ◽  
Elasmobranch Species ◽  
Reproductive Cycles

Elasmobranchs are one of the most endangered vertebrate groups on the planet, but despite this situation the use of reproductive techniques in elasmobranch conservation strategies has been scarce. Among these techniques, sperm preservation is a potential tool for ex situ conservation and aquaria sustainability. However, there are no widespread preservation protocols for elasmobranch sperm, and shark sperm cryopreservation has never been achieved before. Here we present the establishment of successful cryopreservation protocols for elasmobranch sperm, tested in several species. We have formulated a sperm extender that can be used for different elasmobranch species, capable of maintaining sperm motility for several weeks. Additionally, we achieved the cryopreservation of sperm by previously diluting it in our extender and supplementing it with different combinations of cryoprotectants. The effects of methanol and dimethyl sulfoxide as permeating cryoprotectants were evaluated, as well egg yolk as a non-permeating cryoprotectant. Sperm quality was assessed by studying the motility and membrane integrity post-thawing, demonstrating its effectiveness in the 10 species tested, including two which are considered Critically Endangered. This is the first time that shark sperm cryopreservation has been reported, broadening our knowledge of the reproductive techniques that can be applied to elasmobranchs and laying the foundations for the first cryobanks for shark and ray sperm. Outcomes from this study will be useful for ex situ conservation efforts developed by public aquaria. A regular supply of frozen sperm will reduce the problems that result from the transport of specimens, inbreeding or lack of synchronized reproductive cycles in captivity.

scholarly journals Can´t beat the heat? Importance of cardiac control and coronary perfusion for heat tolerance in rainbow trout

2019 ◽  
Vol 189 (6) ◽  
pp. 757-769 ◽  
Author(s):  
Andreas Ekström ◽  
Albin Gräns ◽  
Erik Sandblom
Keyword(s):  
Cardiac Output ◽  
Rainbow Trout ◽  
Heat Tolerance ◽  
Cardiac Failure ◽  
Cardiac Performance ◽  
Coronary Perfusion ◽  
Adrenergic Blockade ◽  
Adrenergic Stimulation ◽  
Autonomic Tone

Abstract Coronary perfusion and cardiac autonomic regulation may benefit myocardial oxygen delivery and thermal performance of the teleost heart, and thus influence whole animal heat tolerance. Yet, no study has examined how coronary perfusion affects cardiac output during warming in vivo. Moreover, while β-adrenergic stimulation could protect cardiac contractility, and cholinergic decrease in heart rate may enhance myocardial oxygen diffusion at critically high temperatures, previous studies in rainbow trout (Oncorhynchus mykiss) using pharmacological antagonists to block cholinergic and β-adrenergic regulation showed contradictory results with regard to cardiac performance and heat tolerance. This could reflect intra-specific differences in the extent to which altered coronary perfusion buffered potential negative effects of the pharmacological blockade. Here, we first tested how cardiac performance and the critical thermal maximum (CTmax) were affected following a coronary ligation. We then assessed how these performances were influenced by pharmacological cholinergic or β-adrenergic blockade, hypothesising that the effects of the pharmacological treatment would be more pronounced in coronary ligated trout compared to trout with intact coronaries. Coronary blockade reduced CTmax by 1.5 °C, constrained stroke volume and cardiac output across temperatures, led to earlier cardiac failure and was associated with reduced blood oxygen-carrying capacity. Nonetheless, CTmax and the temperatures for cardiac failure were not affected by autonomic blockade. Collectively, our data show that coronary perfusion improves heat tolerance and cardiac performance in trout, while evidence for beneficial effects of altered cardiac autonomic tone during warming remains inconclusive.

Enhanced hypo-osmoregulation induced by warm-acclimation in antarctic fish is mediated by increased gill and kidney Na+/K(+)-ATPase activities.

1995 ◽  
Vol 198 (11) ◽  
pp. 2279-2291 ◽  
Author(s):  
P J Gonzalez-Cabrera ◽  
F Dowd ◽  
V K Pedibhotla ◽  
R Rosario ◽  
D Stanley-Samuelson ◽  
...  
Keyword(s):  
Atpase Activity ◽  
Extracellular Fluid ◽  
Antarctic Fish ◽  
Serum Osmolality ◽  
Acclimation Temperature ◽  
Osmotic Gradient ◽  
Inorganic Ion ◽  
Warm Acclimation ◽  
Lower Temperature ◽  
Kidney Liver

Serum osmolality and serum inorganic ion concentrations were studied in two antarctic fish species, Trematomus bernacchii and T. newnesi, during 5 weeks of acclimation to 4 degrees C and compared with control values for groups acclimated to -1.5 degrees C. Acclimation to 4 degrees C significantly decreased the serum osmolality of both species, thereby increasing their seawater-to-extracellular fluid (ECF) osmotic gradient. The decline in osmolality with acclimation to 4 degrees C was accompanied by significant and rapid losses of Na+ and Cl- during the first 14 days of acclimation and was maintained throughout the study period. At day 35 of acclimation, the lipid composition and microsomal Na+/K(+)-ATPase specific activities at 4 degrees C and 37 degrees C were determined in membranes from gill, kidney, liver and muscle tissues. No warm-induced decrease in fatty acid unsaturation was found in the tissues of either species. In the gills and kidneys of both species, the Na+/K(+)-ATPase activities assayed at 4 degrees C were increased after acclimation to 4 degrees C. The Na+/K(+)-ATPase activities at 37 degrees C increased at the higher acclimation temperature in T. newnesi kidneys and T. bernacchii gills, but in both species there was no compensation to temperature in the liver, regardless of assay temperature. Muscle Na+/K(+)-ATPase activity decreased in response to warm-acclimation in T. bernacchii and T. newnesi assayed at 4 degrees C and 37 degrees C, respectively. During acclimation to 4 degrees C, the discontinuity in the Arrhenius plot of the Na+/K(+)-ATPase activities of T. newnesi gill moved to a lower temperature, whereas that of kidney remained unchanged. The results indicate that acclimation to 4 degrees C induced a decrease in serum osmolality which resulted from the positive compensation of Na+/K(+)-ATPase in osmoregulatory tissues. The enhancement in Na+/K(+)-ATPase activity at 4 degrees C suggests that energy expenditure in antarctic fish may be lessened, in part, by maintaining a reduced seawater-to-ECF osmotic gradient.

Haemodynamic Studies in Eight Cases of Acute Colchicine Poisoning

1983 ◽  
Vol 2 (2) ◽  
pp. 169-173 ◽  
Author(s):  
Ph. Sauder ◽  
J. Kopferschmitt ◽  
A. Jaeger ◽  
J.M. Mantz
Keyword(s):  
Cardiac Index ◽  
Cardiac Failure ◽  
Cardiac Performance ◽  
Lethal Outcome ◽  
Haemodynamic Study ◽  
Colchicine Poisoning ◽  
Initial Decrease ◽  
Before And After ◽  
Severe Shock ◽  
Index Of Severity

1 The authors performed haemodynamic studies in 8 cases of colchicine poisoning. The doses absorbed ranged between 9 and 160 mg (mean dose 39 mg). The haemodynamic study was performed between the 6th and 72nd h after intoxication, before and after plasma infusion (370 ml over a period of 20 minutes). 2 Four patients had severe shock with decreased cardiac index (CI) and increased systemic vascular resistance (SVR). Four patients had a hyperkinetic state with increased CI and decreased SVR. The four patients with cardiac failure died, the others recovered. 3 Haemodynamic study of acute colchicine poisoning is of therapeutic and prognostic interest. Hypovolaemia is always present. An initial decrease of cardiac performance is an index of severity with a lethal outcome.

scholarly journals Influence of the coronary circulation on thermal tolerance and cardiac performance during warming in rainbow trout

2017 ◽  
Vol 312 (4) ◽  
pp. R549-R558 ◽  
Author(s):  
Andreas Ekström ◽  
Michael Axelsson ◽  
Albin Gräns ◽  
Jeroen Brijs ◽  
Erik Sandblom
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Rainbow Trout ◽  
Cardiac Function ◽  
Thermal Tolerance ◽  
Coronary Flow ◽  
Coronary Circulation ◽  
Cardiac Performance ◽  
Juvenile Trout

Thermal tolerance in fish may be related to an oxygen limitation of cardiac function. While the hearts of some fish species receive oxygenated blood via a coronary circulation, the influence of this oxygen supply on thermal tolerance and cardiac performance during warming remain unexplored. Here, we analyzed the effect in vivo of acute warming on coronary blood flow in adult sexually mature rainbow trout ( Onchorhynchus mykiss) and the consequences of chronic coronary ligation on cardiac function and thermal tolerance in juvenile trout. Coronary blood flow at 10°C was higher in females than males (0.56 ± 0.08 vs. 0.30 ± 0.08 ml·min−1·g ventricle−1), and averaged 0.47 ± 0.07 ml·min−1·g ventricle−1 across sexes. Warming increased coronary flow in both sexes until 14°C, at which it peaked and plateaued at 0.78 ± 0.1 and 0.61 ± 0.1 ml·min−1·g ventricle−1 in females and males, respectively. Thus, the scope for increasing coronary flow was 101% in males, but only 39% in females. Coronary-ligated juvenile trout exhibited elevated heart rate across temperatures, reduced Arrhenius breakpoint temperature for heart rate (23.0 vs. 24.6°C), and reduced upper critical thermal maximum (25.3 vs. 26.3°C). To further analyze the effects of coronary flow restriction on cardiac rhythmicity, electrocardiogram characteristics were determined before and after coronary occlusion in anesthetized trout. Occlusion resulted in reduced R-wave amplitude and an elevated S-T segment, indicating myocardial ischemia, while heart rate was unaffected. This suggests that the tachycardia in ligated trout across temperatures in vivo was mainly to compensate for reduced cardiac contractility to maintain cardiac output. Moreover, our findings show that coronary flow increases with warming in a sex-specific manner. This may improve whole animal thermal tolerance, presumably by sustaining cardiac oxygenation and contractility at high temperatures.

scholarly journals Design and optimization of an experimental maintenance system for yellow clam broodstock Amarilladesma mactroides (Reeve, 1854)

2022 ◽  
Vol 82 ◽  
Author(s):  
N. B. Gauthier ◽  
F. S. Goes ◽  
L. Quaresma ◽  
V. F. Pedrosa ◽  
F. Roselet ◽  
...  
Keyword(s):  
Anthropogenic Activities ◽  
Feasibility Studies ◽  
Gonadal Development ◽  
North Coast ◽  
Oocyte Diameter ◽  
High Survival ◽  
Design And Optimization ◽  
The North ◽  
Management Protocol ◽  
In Captivity

Abstract The yellow clam is a sand-burrowing bivalve that inhabits the dissipative beaches from southern Brazil to the north coast of Argentina. In the last decades, populations of this species have been impacted by mass mortality events, overfishing and other anthropogenic activities. The production of juveniles in captivity would allow feasibility studies to be carried out to restore the natural stock as well as the production in aquaculture systems. Given the scarcity of studies on the maintenance of this species in captivity, a culture system and a management protocol were developed and tested. Wild-caught clams (total length ≥50 mm) were used in a series of 14 day-long trials. Survival was higher in clams that were allowed to bury into the sand. A permanent ink marker covered with a thin layer of a quick-hardening adhesive proved to be a reliable method to tag clams. The maintenance of yellow clams in this system resulted in high survival and growth, increases in the condition factor and oocyte diameter, and a relative advancement of gonadal development.

scholarly journals Spider Mites Singly Infected With Either Wolbachia or Spiroplasma Have Reduced Thermal Tolerance

2021 ◽  
Vol 12 ◽  
Author(s):  
Yu-Xi Zhu ◽  
Zhang-Rong Song ◽  
Yi-Yin Zhang ◽  
Ary A. Hoffmann ◽  
Xiao-Yue Hong
Keyword(s):  
High Temperature ◽  
Thermal Tolerance ◽  
Spider Mite ◽  
Heat Exposure ◽  
Dependent Manner ◽  
Bacterial Replication ◽  
Lower Temperature ◽  
Temperature Exposure ◽  
Temperature Impacts ◽  
The Impact

Heritable symbionts play an essential role in many aspects of host ecology in a temperature-dependent manner. However, how temperature impacts the host and their interaction with endosymbionts remains largely unknown. Here, we investigated the impact of moderate (20°C) and high (30 and 35°C) temperatures on symbioses between the spider mite Tetranychus truncatus and two maternally inherited endosymbionts (Wolbachia and Spiroplasma). We found that the thermal tolerance of mites (as measured by survival after heat exposure) was lower for mites that were singly infected with either Wolbachia or Spiroplasma than it was for co-infected or uninfected mites. Although a relatively high temperature (30°C) is thought to promote bacterial replication, rearing at high temperature (35°C) resulted in losses of Wolbachia and particularly Spiroplasma. Exposing the mites to 20°C reduced the density and transmission of Spiroplasma but not Wolbachia. The four spider mite strains tested differed in the numbers of heat shock genes (Hsps) induced under moderate or high temperature exposure. In thermal preference (Tp) assays, the two Wolbachia-infected spider mite strains preferred a lower temperature than strains without Wolbachia. Our results show that endosymbiont-mediated spider mite responses to temperature stress are complex, involving a combination of changing endosymbiont infection patterns, altered thermoregulatory behavior, and transcription responses.

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