scholarly journals Effects of zinc on the kinetics of branchial calcium uptake in freshwater rainbow trout during adaptation to waterborne zinc

1994 ◽  
Vol 186 (1) ◽  
pp. 55-73 ◽  
Author(s):  
C. Hogstrand ◽  
R. W. Wilson ◽  
D. Polgar ◽  
C. M. Wood
Keyword(s):  
Rainbow Trout ◽  
Calcium Uptake ◽  
Prolonged Exposure ◽  
Hard Water ◽  
Exposure Period ◽  
Inhibitory Effect ◽  
Fold Reduction ◽  
Uptake Sites ◽  
Waterborne Zinc ◽  
Kinetics Of

The effects of sublethal waterborne Zn2+ (150 micrograms l-1 = 2.3 mumol-1) on the kinetics of unidirectional Ca2+ influx were studied in juvenile freshwater rainbow trout during chronic exposure (60 days) at a water [Ca2+] of 1.0 mmol l-1. An unexposed group held under identical conditions served as control. The presence of Zn2+ in the water increased the apparent Km for Ca2+ influx by up to 300% with only a small inhibitory effect (35% at most) on the maximum rate of uptake (Jmax). These results, in combination with earlier data showing that Ca2+ competitively inhibits Zn2+ uptake, suggest that Zn2+ and Ca2+ compete for the same uptake sites. Acute withdrawal of Zn2+ after 3h of exposure resulted in a 23-fold reduction in Km for Ca2+, but a persistent small depression of Jmax. During prolonged exposure to Zn2+, the apparent Km for Ca2+ remained greatly elevated and Jmax remained slightly depressed. The actual Ca2+ influx in hard water ([Ca2+] = 1.0 mmol l-1) decreased marginally and paralleled the small changes in Jmax. The increases in apparent Km had a negligible influence on the actual Ca2+ influx because Km values (38–230 mumol l-1), even when elevated by Zn2+, remained below the water [Ca2+] (1000 mumol l-1). Rainbow trout exposed to Zn2+ exhibited a slower rate of protein synthesis in the gills (measured on day 23) and an increased tolerance to Zn2+ challenge (measured on both days 27 and 50). Unidirectional Zn2+ influx, measured at the end of the exposure period, was significantly reduced in the Zn2+-exposed fish. There were no changes in hepatic or branchial Zn2+, Cu2+ or metallothionein concentrations. We hypothesize that, during exposure to sublethal [Zn2+] in hard water, the fish may change the Km for a mutual Ca2+/Zn2+ carrier so as to reduce markedly Zn2+ influx without greatly altering Ca2+ influx. This reduced Zn2+ influx, rather than metallothionein induction, may be the basis of adaptation to elevated concentrations of waterborne Zn2+.

scholarly journals Hypocalcin from Stannius corpuscles inhibits gill calcium uptake in trout

1988 ◽  
Vol 254 (6) ◽  
pp. R891-R896 ◽  
Author(s):  
F. P. Lafeber ◽  
G. Flik ◽  
S. E. Wendelaar Bonga ◽  
S. F. Perry
Keyword(s):  
Rainbow Trout ◽  
Calcium Uptake ◽  
Inhibitory Effect ◽  
Whole Body ◽  
Transepithelial Potential ◽  
Low Calcium ◽  
Stannius Corpuscles ◽  
Normal Calcium

Bidirectional whole body flux and branchial Ca2+ influx were measured in freshwater rainbow trout. Intra-arterial injections of homogenates of Stannius corpuscles (CS) as well as of a 54-kDa isolated product (hypocalcin) exerted an inhibitory effect on whole body Ca2+ influx, but did not effect Ca2+ efflux. Hypocalcin was more effective in reducing Ca2+ influx in trout acclimated to low-calcium freshwater than in fish from normal-calcium water. We conclude that the isolated product (hypocalcin) represents the hypocalcemic principle of the CS. Similar doses of hypocalcin caused quantitatively similar decreases in Ca2+ influx in vivo and in the isolated perfused head preparation. This indicates that the gills form the principle target for hypocalcin in trout. The branchial transepithelial potential did not change during hormone treatments. Possible mechanisms of hypocalcin action are suggested.

Biochemical responses in gills of rainbow trout exposed to propiconazole

2011 ◽  
Vol 6 (1) ◽  
pp. 84-90 ◽  
Author(s):  
Zhi-Hua Li ◽  
Vladimir Zlabek ◽  
Roman Grabic ◽  
Ping Li ◽  
Tomas Randak
Keyword(s):  
Rainbow Trout ◽  
Laboratory Experiments ◽  
Prolonged Exposure ◽  
Exposure Period ◽  
Significant Inhibition ◽  
Aquatic Environments ◽  
Defense System ◽  
Fish Gill ◽  
Biochemical Responses ◽  
Sublethal Concentrations

AbstractThe aim of this study is to investigate the toxic effect of PCZ, a triazole fungicide commonly present in surface and ground water, on the ROS defense system and Na+-K+-ATPase in gills of rainbow trout exposed to sublethal concentrations (0.2, 50 and 500 μg L−1) for 7, 20 and 30 days. After prolonged exposure of PCZ at higher test concentrations (50 and 500 μg L−1), oxidative stress was apparent as reflected by the significant higher ROS levels in fish gill, as well as the significant inhibition of SOD and CAT activities. In addition, Na+-K+-ATPase activities were significantly lower than those of the control with increasing PCZ concentration and prolonged exposure period. The results of this study indicate that chronic exposure to PCZ has altered multiple physiological indices in fish gill; however, before these parameters are used as unique biomarkers for monitoring residual pharmaceuticals in aquatic environments, more detailed laboratory experiments need to be performed.

Erratum

1986 ◽  
Vol 123 (1) ◽  
pp. 216-216
Author(s):  
S. F. PERRY ◽  
C. M. WOOD
Keyword(s):  
Rainbow Trout ◽  
Calcium Uptake ◽  
Kinetics Of ◽  
External Calcium

Kinetics of branchial calcium uptake in the rainbow trout: effects of acclimation to various external calcium levels. J. exp. Biol. 116, 411–433.

scholarly journals Kinetics of Branchial Calcium Uptake in the Rainbow Trout: Effects of Acclimation to Various External Calcium Levels

1985 ◽  
Vol 116 (1) ◽  
pp. 411-433 ◽  
Author(s):  
S. F. PERRY ◽  
C. M. WOOD
Keyword(s):  
Rainbow Trout ◽  
Calcium Uptake ◽  
Chloride Cells ◽  
Arterial Circulation ◽  
In Vivo Experiments ◽  
Kinetics Of ◽  
Fold Stimulation ◽  
External Calcium

Calcium uptake (JCain) in freshwater rainbow trout (Salmo gairdnen) under control conditions (external [Ca2+] ≃ 1.8 mequivl−1, [NaCl] ≃ 0.8 mequiv 1−1) occurred at approximately equal rates (12–15 μequiv kg−1 h−1) through the gills and the general body surface in vivo. The gut was not involved. Under the same conditions, in vitro branchial JCain in an isolated, saline-perfused head preparation was equal to that in vivo. The cells involved in JinCa are mainly located on lamellae rather than on filaments since 95 % of JinCa occurred across the arterio-arterial circulation of the gill. JinCa, in vitro, displayed Michaelis-Menten kinetics. Acclimation to low external [Ca2+] (50 μequiv 1−1; unchanged [NaCl]) for 1 day caused a five-fold stimulation of JinCa characterized by decreased Km and increased J max. Longer periods of low [Ca2+] acclimation resulted in changes of Jmax only. Jmax gradually returned towards control levels as acclimation time increased, but was still elevated after 30 days. Acclimation to low ambient [Ca2+] caused proliferation and increased exposure of lamellar chloride cells which were correlated with increased Jmax. Fish exposed to high external [Ca2+] (10 mequivl−1; unchanged [NaCl]) displayed reduced JinCa Similar changes in JinCa were observed during in vivo experiments. Plasma Ca2+ concentration remained constant regardless of external [Ca2+], while plasma Na+ and Cl− levels were transiently reduced at 1 day low [Ca2+] exposure but had recovered by 7 days. A possible role for cortisol in Ca2+ regulation is discussed based on observations of cortisol-stimulated lamellar chloride cell proliferation and JinCa, and elevated plasma [cortisol] in low-[Ca2+] acclimated fish.

The effect of origin and physico-chemical properties on the kinetics of reduction of mixed NiO-Fe2O3 oxides with hydrogen

1986 ◽  
Vol 51 (10) ◽  
pp. 2098-2108 ◽  
Author(s):  
Milan Pospíšil ◽  
Jan Topinka
Keyword(s):  
Mixed Oxides ◽  
Mutual Influence ◽  
Spinel Phase ◽  
Chemical Properties ◽  
Inhibitory Effect ◽  
Chemical Parameters ◽  
Physico Chemical ◽  
Preliminary Annealing ◽  
Kinetics Of ◽  
Kinetics Of Reduction

We investigated the effect of origin and some physico-chemical parameters on the kinetics of reduction with hydrogen of two series of mixed NiO-Fe2O3 oxides differing by their composition, the character of their precursors (mixed crystalline nitrates and coprecipitated hydroxides) and their decomposition temperature.This effect manifested itself by different magnitudes of specific surfaces of the mixed oxides and coherent regions of present phases as well as by different oxidizing abilities of the surface and differences in morphology and phase composition of corresponding samples in both series investigated. Nonlinear or nonmonotonous composition dependences of physico-chemical parameters investigated point to a mutual influence of individual components, which is also a function of the system origin and which modifies its reactivity during its reduction with hydrogen. The kinetics of the reduction was studied thermogravimetrically at 320-410 °C. The reduction of oxides of the hydroxide origin is catalytically accelerated by primarily reduced nickel, whereas in corresponding samples of the nitrate series, the total NiO is bound to the spinel phase and the reduction is delayed. Experimental IR spectra, the effect of preliminary annealing and DTA of the mixed oxides point to an inhibitory effect of water, which is constitutionally bound in trace admixtures of the goethite phase, on the kinetics of reduction of samples in the hydroxide series.

Kinetics of calcium uptake by isolated sarcoplasmic reticulum vesicles using flash photolysis of caged ATP

Biochemistry ◽  
1983 ◽  
Vol 22 (23) ◽  
pp. 5254-5261 ◽  
Author(s):  
Dorothy H. Pierce ◽  
Antonio Scarpa ◽  
Michael R. Topp ◽  
J. Kent Blasie
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Calcium Uptake ◽  
Flash Photolysis ◽  
Caged Atp ◽  
Kinetics Of

scholarly journals Myricetin as an Antivirulence Compound Interfering with a Morphological Transformation into Coccoid Forms and Potentiating Activity of Antibiotics against Helicobacter pylori

2021 ◽  
Vol 22 (5) ◽  
pp. 2695
Author(s):  
Paweł Krzyżek ◽  
Paweł Migdał ◽  
Emil Paluch ◽  
Magdalena Karwańska ◽  
Alina Wieliczko ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Biofilm Formation ◽  
Inhibitory Effect ◽  
Morphological Transformation ◽  
High Tendency ◽  
Minimal Inhibitory Concentrations ◽  
Coccoid Form ◽  
Stomach Diseases ◽  
Fold Reduction ◽  
H Pylori

Helicobacter pylori, a gastric pathogen associated with a broad range of stomach diseases, has a high tendency to become resistant to antibiotics. One of the most important factors related to therapeutic failures is its ability to change from a spiral to a coccoid form. Therefore, the main aim of our original article was to determine the influence of myricetin, a natural compound with an antivirulence action, on the morphological transformation of H. pylori and check the potential of myricetin to increase the activity of antibiotics against this pathogen. We observed that sub-minimal inhibitory concentrations (sub-MICs) of this compound have the ability to slow down the process of transformation into coccoid forms and reduce biofilm formation of this bacterium. Using checkerboard assays, we noticed that the exposure of H. pylori to sub-MICs of myricetin enabled a 4–16-fold reduction in MICs of all classically used antibiotics (amoxicillin, clarithromycin, tetracycline, metronidazole, and levofloxacin). Additionally, RT-qPCR studies of genes related to the H. pylori morphogenesis showed a decrease in their expression during exposure to myricetin. This inhibitory effect was more strongly seen for genes involved in the muropeptide monomers shortening (csd3, csd6, csd4, and amiA), suggesting their significant participation in the spiral-to-coccoid transition. To our knowledge, this is the first research showing the ability of any compound to synergistically interact with all five antibiotics against H. pylori and the first one showing the capacity of a natural substance to interfere with the morphological transition of H. pylori from spiral to coccoid forms.

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