scholarly journals Rainbow Trout (Oncorhynchus mykiss) Na+/H+ Exchangers tNhe3a and tNhe3b Display Unique Inhibitory Profiles Dissimilar from Mammalian NHE Isoforms

2021 ◽  
Vol 22 (4) ◽  
pp. 2205
Author(s):  
Salvatore Blair ◽  
Xiuju Li ◽  
Debajyoti Dutta ◽  
Danuta Chamot ◽  
Larry Fliegel ◽  
...  
Keyword(s):  
Oncorhynchus Mykiss ◽  
Significant Activity ◽  
Dependent Manner ◽  
Important Species ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Transport Studies ◽  
Direct Interpretation ◽  
Acid Load ◽  
Transport Inhibitors ◽  
High Concentrations

Freshwater fishes maintain an internal osmolality of ~300 mOsm, while living in dilute environments ranging from 0 to 50 mOsm. This osmotic challenge is met at least partially, by Na+/H+ exchangers (NHE) of fish gill and kidney. In this study, we cloned, expressed, and pharmacologically characterized fish-specific Nhes of the commercially important species Oncorhynchus mykiss. Trout (t) Nhe3a and Nhe3b isoforms from gill and kidney were expressed and characterized in an NHE-deficient cell line. Western blotting and immunocytochemistry confirmed stable expression of the tagged trout tNhe proteins. To measure NHE activity, a transient acid load was induced in trout tNhe expressing cells and intracellular pH was measured. Both isoforms demonstrated significant activity and recovered from an acute acid load. The effect of the NHE transport inhibitors amiloride, EIPA (5-(N-ethyl-N-isopropyl)-amiloride), phenamil, and DAPI was examined. tNhe3a was inhibited in a dose-dependent manner by amiloride and EIPA and tNhe3a was more sensitive to amiloride than EIPA, unlike mammalian NHE1. tNhe3b was inhibited by high concentrations of amiloride, while even in the presence of high concentrations of EIPA (500 µM), some activity of tNhe3b remained. Phenamil and DAPI were ineffective at inhibiting tNhe activity of either isoform. The current study aids in understanding the pharmacology of fish ion transporters. Both isoforms display inhibitory profiles uniquely different from mammalian NHEs and show resistance to inhibition. Our study allows for more direct interpretation of past, present, and future fish-specific sodium transport studies, with less reliance on mammalian NHE data for interpretation.

scholarly journals Biochemical and functional analysis of a conserved IGF-binding protein isolated from rainbow trout (Oncorhynchus mykiss) hepatoma cells

2001 ◽  
Vol 170 (3) ◽  
pp. 619-628 ◽  
Author(s):  
◽  
A Garmong ◽  
P Swanson ◽  
J Moore ◽  
M Lin ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Hepatoma Cells ◽  
Dependent Manner ◽  
High Sequence Identity ◽  
Concentration Dependent Manner ◽  
Igf Binding Proteins ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Igf I ◽  
Igf Binding

Rainbow trout (Oncorhynchus mykiss) serum contains several IGF-binding proteins (IGFBPs) that specifically bind to IGFs. The structures of these fish IGFBPs have not been determined and their physiological functions are poorly defined. In this study, we identified a 30 kDa IGFBP present in rainbow trout serum and secreted by cultured trout hepatoma cells. This IGFBP binds to IGFs but not to insulin. This IGFBP was purified to homogeneity using a three-step procedure involving Phenyl-Sepharose chromatography, IGF-I affinity chromatography and reverse-phase HPLC. Affinity cross-linking studies indicated that this IGFBP binds to IGF-I with a higher affinity than to IGF-II. N-terminal sequence analysis of the trout IGFBP suggests that it shares high sequence identity with that of human IGFBP-1 in the N-terminal region. When added to cultured fish and human cells, the trout IGFBP inhibited IGF-I-stimulated DNA synthesis and cell proliferation in a concentration-dependent manner. The inhibitory effect of the fish IGFBP was comparable to those of human IGFBP-1 and -4. These results indicate that the IGFBP molecule is structurally and functionally conserved in evolutionarily ancient vertebrate species such as bony fish.

scholarly journals MN and ZN content in eggs and musculature of rainbow trout ( Oncorhynchus Mykiss W. ) treated with fungicide mancozeb and pigment astaxanthin

2018 ◽  
Vol 16 (4) ◽  
pp. 275-283
Author(s):  
E. Valkova ◽  
V. Atanasov ◽  
M. Tzanova ◽  
S. Denev
Keyword(s):  
Experimental Data ◽  
Heavy Metals ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Modern Method ◽  
Carotenoid Pigment ◽  
Metabolic Disturbances ◽  
Normative Documents ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
High Concentrations

The present study aims to determine the levels of the heavy metals manganese (Mn) and zinc (Zn) contained in the fungicide Mancozeb in the eggs and musculature of the rainbow trout (Oncorhynchus mykiss W.) which have grown in an environment, containing a permissible amount of Mancozeb and fed with or without the carotenoid pigment astaxanthin. The study follows the feeding, then the analysis of the level of Mn and Zn in the eggs and musculature of the rainbow trout, treated with and without the pigment astaxanthin and the fungicide Mancozeb. The determination of Mn and Zn concentrations is performed using a modern method for measuring macro- and microelements with an atomic absorption spectrometer, which is characterized by high selectivity, swiftness and sensitivity. Experimental data show accumulation of Mn and Zn, contained in the fungicide Mancozeb even when its concentration in the habitat does not exceed the maximum permissible levels in the normative documents. As a result, the analysis of the eggs and musculature shows the same trend regarding the accumulation of Mn and Zn. In non-fertilized, as well as in fertilized rainbow trout eggs and musculature, the experimental data show a slight increase of Mn and Zn in the presence of only astaxanthin in the added feed and a significant decrease in these metals in the presence of both astaxanthin and Mancozeb. The supplementation of astaxanthin in the diet can significantly reduce the rate of heavy metals accumulation in fish tissues and eggs, but high concentrations of these pollutants in the aquatic environment over a longer period of time would certainly result in metabolic disturbances in the fish body and reduction of their eggs’ hatchability.

Substrate- and effector-induced conformational changes in phosphofructokinase from white muscle of rainbow trout (Oncorhynchus mykiss): a fluorescence study

1993 ◽  
Vol 71 (5-6) ◽  
pp. 255-259 ◽  
Author(s):  
Jeffrey Y. Su ◽  
Kenneth B. Storey
Keyword(s):  
Enzyme Activity ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Conformational Changes ◽  
Inorganic Compounds ◽  
Tryptophan Fluorescence ◽  
Fish Muscle ◽  
Spectral Studies ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
High Concentrations

Results of activity and spectral studies using fluorescence show that AMP and fructose 2,6-bisphosphate (F2,6P2) activate muscle phosphofructokinase (PFK) from rainbow trout (Oncorhynchus mykiss) through specific and similar conformational changes. Inorganic compounds, such as ammonium and phosphate ions, also increase enzyme activity allosterically; however, the structural alterations in the enzyme caused by these effectors are quite different from those caused by AMP and F2,6P2. No effects of the inorganic compounds on the environment of tryptophan residues of the enzyme were observed. Mg-ATP, a substrate of the enzyme, acts as an allosteric inhibitor at high concentrations. Although Mg-ATP and citrate inhibit the enzyme activity in a synergistic way, the conformational effects of these negative effectors are different. Mg-ATP caused a drastic decrease in fluorescence intensity of the enzyme, whereas citrate did not.Key words: 6-phosphofructo-1-kinase, tryptophan fluorescence, fructose 2,6-bisphosphate, fish muscle glycolysis.

The essential oils of some medicinal plants on the immune system of rainbow trout (Oncorhynchus mykiss)

Planta Medica ◽  
2012 ◽  
Vol 78 (11) ◽  
Author(s):  
A Ghasemi Pirbalouti ◽  
E Pirali ◽  
G Pishkar ◽  
S Mohammadali Jalali ◽  
M Reyesi ◽  
...  
Keyword(s):  
Immune System ◽  
Rainbow Trout ◽  
Medicinal Plants ◽  
Oncorhynchus Mykiss ◽  
Essential Oils ◽  
Rainbow Trout Oncorhynchus Mykiss

Neutrophil Elastase Potentiates Cathepsin G-lnduced Platelet Activation

1992 ◽  
Vol 68 (05) ◽  
pp. 570-576 ◽  
Author(s):  
Mary A Selak
Keyword(s):  
Neutrophil Elastase ◽  
Cell Activation ◽  
Thromboxane A2 ◽  
Creatine Phosphate ◽  
Dense Granule ◽  
Cathepsin G ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Low Concentrations ◽  
High Concentrations

SummaryWe have previously demonstrated that human neutrophil cathepsin G is a strong platelet agonist that binds to a specific receptor. This work describes the effect of neutrophil elastase on cathepsin G-induced platelet responses. While platelets were not activated by high concentrations of neutrophil elastase by itself, elastase enhanced aggregation, secretion and calcium mobilization induced by low concentrations of cathepsin G. Platelet aggregation and secretion were potentiated in a concentration-dependent manner by neutrophil elastase with maximal responses observable at 200 nM. Enhancement was observed when elastase was preincubated with platelets for time intervals of 10–60 s prior to addition of a low concentration of cathepsin G and required catalytically-active elastase since phenylmethanesulphonyl fluoride-inhibited enzyme failed to potentiate cell activation. Neutrophil elastase potentiation of platelet responses induced by low concentrations of cathepsin G was markedly inhibited by creatine phosphate/creatine phosphokinase and/or indomethacin, indicating that the synergism between elastase and cathepsin G required the participation of ADP and thromboxane A2. On the other hand, platelet responses were not attenuated by the PAF antagonist BN 52021, signifying that PAF-acether did not play a role in elastase potentiation. At higher concentrations porcine pancreatic elastase exhibits similar effects to neutrophil elastase, demonstrating that the effect of elastase was not unique to the neutrophil protease. While neutrophil elastase failed to alter the ability of cathepsin G to hydrolyze a synthetic chromogenic substrate, preincubation of platelets with elastase increased the apparent affinity of cathepsin G binding to platelets. In contrast to their effect on cathepsin G-induced platelet responses, neither neutrophil nor pancreatic elasatse potentiated aggregation or dense granule release initiated by ADP, PAF-acether, arachidonic acid or U46619, a thromboxane A2 mimetic. Moreover, unlike its effect on cathepsin G, neutrophil elastase inhibited thrombin-induced responses. The current observations demonstrate that elastase can potentiate platelet responses mediated by low concentrations of cathepsin G, suggesting that both enzymes may function synergistically to activate platelets under conditions where neutrophil degranulation occurs.

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