The in vitro effects of some pesticides on carbonic anhydrase activity of Oncorhynchus mykiss and Cyprinus carpio carpio fish

ABSTRACT The role of the periplasmic α-carbonic anhydrase (α-CA) (HP1186) in acid acclimation of Helicobacter pylori was investigated. Urease and urea influx through UreI have been shown to be essential for gastric colonization and for acid survival in vitro. Intrabacterial urease generation of NH3 has a major role in regulation of periplasmic pH and inner membrane potential under acidic conditions, allowing adequate bioenergetics for survival and growth. Since α-CA catalyzes the conversion of CO2 to HCO3 −, the role of CO2 in periplasmic buffering was studied using an α-CA deletion mutant and the CA inhibitor acetazolamide. Western analysis confirmed that α-CA was bound to the inner membrane. Immunoblots and PCR confirmed the absence of the enzyme and the gene in the α-CA knockout. In the mutant or in the presence of acetazolamide, there was an ∼3 log10 decrease in acid survival. In acid, absence of α-CA activity decreased membrane integrity, as observed using membrane-permeant and -impermeant fluorescent DNA dyes. The increase in membrane potential and cytoplasmic buffering following urea addition to wild-type organisms in acid was absent in the α-CA knockout mutant and in the presence of acetazolamide, although UreI and urease remained fully functional. At low pH, the elevation of cytoplasmic and periplasmic pH with urea was abolished in the absence of α-CA activity. Hence, buffering of the periplasm to a pH consistent with viability depends not only on NH3 efflux from the cytoplasm but also on the conversion of CO2, produced by urease, to HCO3 − by the periplasmic α-CA.

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In vitro effects of Thiram on liver antioxidant enzyme activities of rainbow trout (Oncorhynchus mykiss)

Aquatic Toxicology ◽

10.1016/0166-445x(92)90036-m ◽

1992 ◽

Vol 22 (1) ◽

pp. 61-68 ◽

Cited By ~ 38

Author(s):

S. Babo ◽

P. Vasseur

Keyword(s):

Rainbow Trout ◽

Oncorhynchus Mykiss ◽

Antioxidant Enzyme ◽

Enzyme Activities ◽

Antioxidant Enzyme Activities ◽

Rainbow Trout Oncorhynchus Mykiss ◽

In Vitro Effects

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INHIBITORS OF CARBONIC ANHYDRASE IN THE AMERICAN COCKROACH, PERIPLANETA AMERICANA (L.)

Canadian Journal of Zoology ◽

10.1139/z56-010 ◽

1956 ◽

Vol 34 (1) ◽

pp. 68-74 ◽

Cited By ~ 14

Author(s):

Ann D. Anderson ◽

Ralph B. March

Keyword(s):

Carbonic Anhydrase ◽

Periplaneta Americana ◽

Fat Body ◽

Aqueous Media ◽

Carbonic Anhydrase Activity ◽

American Cockroach ◽

Tissue Homogenates ◽

Organic Insecticides ◽

Cell Fragments

Carbonic anhydrase activity has been demonstrated in vitro in preparations of the head, fat body, and gut of the American cockroach, Periplaneta americana (L.), and in the adult housefly, Musca domestica L. The insect factor, which is soluble in aqueous media and can be separated from the particulate cell fragments of insect tissue homogenates is heat labile and sensitive to cyanide inactivation. It is strongly inhibited by sulphanilamide, p-aminoethylphenyl-sulphonamide, and p-chlorphenylsulphonamide. No inhibition has been found with N-substituted sulphonamides or with any of the organic insecticides examined, including DDT, lindane, dieldrin, nicotine, rotenone, pyrethrins, and para-oxon. Sensitivity of carbonic anhydrase to sulphonamides having an intact—SO2NH2 group is also characteristic of mammalian preparations. The data indicate that inhibition of insect carbonic anhydrase cannot be an important factor in the mode of action of DDT or other organic insecticides.

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