Blood oxygen transport in stressed striped bass (Morone saxatilis): role of beta-adrenergic responses

1984 ◽  
Vol 154 (4) ◽  
pp. 365-369 ◽  
Author(s):  
Mikko Nikinmaa ◽  
Joseph J. Cech ◽  
Maryann McEnroe
2011 ◽  
Vol 209 (1) ◽  
pp. 115-126 ◽  
Author(s):  
Pia Kiilerich ◽  
Christian K Tipsmark ◽  
Russell J Borski ◽  
Steffen S Madsen

The role of cortisol as the only corticosteroid in fish osmoregulation has recently been challenged with the discovery of a mineralocorticoid-like hormone, 11-deoxycorticosterone (DOC), and necessitates new studies of the endocrinology of osmoregulation in fish. Using an in vitro gill explant incubation approach, DOC-mediated regulation of selected osmoregulatory target genes in the gill was investigated and compared with that of cortisol in two euryhaline teleosts, Mozambique tilapia (Oreochromis mossambicus) and striped bass (Morone saxatilis). The effects were tested in gills from both fresh water (FW)- and seawater (SW)-acclimated fish. Both cortisol and DOC caused an up-regulation of the Na+,K+-ATPase α1 subunit in SW-acclimated tilapia but had no effect in FW-acclimated fish. Cortisol conferred an increase in Na+,K+,2Cl− cotransporter (NKCC) isoform 1a transcript levels in FW- and SW-acclimated tilapia, whereas DOC had a stimulatory effect only in SW-acclimated fish. Cortisol had no effect on NKCC isoform 1b mRNA levels at both salinities, while DOC stimulated this isoform in SW-acclimated fish. In striped bass, cortisol conferred an up-regulation of Na+,K+-ATPase α1 and NKCC transcript levels in FW- and SW-acclimated fish, whereas DOC resulted in down-regulation of these transcripts in FW-acclimated fish. It was also found that both corticosteroids may rapidly (30 min) alter the mitogen-activated protein kinase signalling pathway in gill, inducing phosphorylation of extracellular signal-regulated kinase 1 (ERK1) and ERK2 in a salinity-dependent manner. The study shows a disparate organisation of corticosteroid signalling mechanisms involved in ion regulation in the two species and adds new evidence to a role of DOC as a mineralocorticoid hormone in teleosts.


1991 ◽  
Vol 260 (4) ◽  
pp. R798-R803
Author(s):  
M. Riera ◽  
J. F. Fuster ◽  
L. Palacios

The effects of two different degrees of experimentally induced anemia and the consequent high percentage of circulating immature erythrocytes on oxygen affinity (pH 7.5 and 41 degrees C), erythrocyte organic phosphates, and Hb fractions have been studied in quail. Blood reticulocytes reached percentages of 24 and 69-87% in the first and second experiments, respectively. Variations in the phosphate levels found during the anemic process were related to the amount of circulating reticulocytes. The erythrocyte [ATP] (brackets indicate concentration) and [ATP]/[Hb] molar ratio increased with the release of reticulocytes and returned to control levels as they matured. The erythrocyte [inositol pentakisphosphate (InsP5)] decreased significantly when circulating reticulocytes showed their highest values, whereas there was hardly any effect on the [InsP5]/[Hb] molar ratio, which changed only slightly. Hb-O2 affinity also exhibited no statistical changes associated with acute anemia. These latter findings indicate that InsP5, at physiological concentrations, is the primary modulator of quail Hb function; the observed rise in [ATP] has no additional influence on Hb-O2 affinity. It is suggested that InsP5 tends to maintain the blood oxygen affinity in both mature erythrocytes and reticulocytes. The main compensatory response at blood level is a rapid bulk reticulocyte release from medulla.


2020 ◽  
Vol 142 ◽  
pp. 47-53
Author(s):  
K Béland ◽  
G Séguin ◽  
S Lair

An unusually high mortality rate due to verminous (Philometra rubra) coelomitis was documented in wild-hatched striped bass Morone saxatilis raised in a fish hatchery as part of a stock restoration program. To decrease the parasitic burden and therefore potentially minimize mortality, the effectiveness of 2 different anthelmintics was evaluated. Two trials were conducted on wild-collected fingerlings naturally infected by P. rubra. In 2006, 144 yearling fish were randomly assigned to 4 experimental groups: (1) levamisole (Levasol®) at 2 mg l-1 via immersion for 8 h once weekly for 3 wk; (2) levamisole at a dose of 2.5 mg kg-1 biomass via feed once daily for 7 d; (3) emamectin benzoate (Slice®) at a dose of 0.05 mg kg-1 biomass via feed once daily for 7 d; and (4) control. Emamectin successfully eliminated live nematodes in 84.9% of the fish, whereas the administration of levamisole, either via immersion or feed, was not successful in significantly reducing the number of live P. rubra. In 2007, the administration of the same dosage of emamectin to approximately 1000 naturally infected yearling striped bass was associated with a 100% mortality rate of P. rubra in the 30 fish randomly examined 5 wk after the beginning of the treatment. Results of these trials indicate that, at the dosage used, the administration of emamectin at the end of the summer is safe for striped bass yearlings and considerably reduces the prevalence and intensity of the infection by this parasite.


Mathematics ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 910
Author(s):  
Andrey Kovtanyuk ◽  
Alexander Chebotarev ◽  
Varvara Turova ◽  
Irina Sidorenko ◽  
Renée Lampe

An inverse problem for a system of equations modeling oxygen transport in the brain is studied. The problem consists of finding the right-hand side of the equation for the blood oxygen transport, which is a linear combination of given functionals describing the average oxygen concentration in the neighborhoods of the ends of arterioles and venules. The overdetermination condition is determined by the values of these functionals evaluated on the solution. The unique solvability of the problem is proven without any smallness assumptions on the model parameters.


2019 ◽  
Vol 41 (4) ◽  
pp. 507-520 ◽  
Author(s):  
L Vanalderweireldt ◽  
P Sirois ◽  
M Mingelbier ◽  
G Winkler

Abstract After being extirpated from the St. Lawrence River in the 1960s, striped bass (Morone saxatilis) were reintroduced to the estuary in 2002 and by 2008, they were naturally reproducing. To document the habitat use and feeding ecology of this reintroduced population, we examined the gut contents of 333 larvae and juveniles. Samples were collected in four estuarine habitats in 2014: the upstream freshwater section (UP), the oligohaline (O-ETM) and the mesohaline (M-ETM) estuarine turbidity maximum zones, and the downstream polyhaline section (DOWN). In June, pelagic larvae developed in the UP and the O-ETM, feeding mainly on copepods such as Eurytemora affinis. The O-ETM exhibited better suitable feeding conditions compared to the UP, likely due to the presence of Bosmina sp. as a primary prey. After July, striped bass shifted to larger prey items, consuming mainly dipteran pupa in upstream littoral habitats and gammarids and mysids in downstream habitats. In the early summer, the UP provided a high-quality nursery habitat and as the season progressed, the smallest juveniles dispersed downstream and improved their feeding success by exploiting a new feeding niche. This observation suggests that being distributed throughout the estuary may increase the potential survival of striped bass early life stages.


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