Carbon tetrachloride toxicity on Escherichia coli exacerbated by superoxide.

H Yamamoto,T Nagano,M Hirobe

doi:10.1016/s0021-9258(18)37743-3

H Yamamoto, T Nagano + Show 1 more

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https://doi.org/10.1016/s0021-9258(18)37743-3

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Abstract

The effects of carbon tetrachloride (CCl4) and paraquat on the growth of Escherichia coli were investigated. Paraquat at 10 mM caused some inhibition of growth of E. coli in trypticase-soy-yeast extract medium. CCl4 enhanced growth inhibition by paraquat in a concentration-dependent manner. In the absence of paraquat, CCl4 had no effect on growth rate or on surviving cell numbers at stationary phase. CCl4 did not prevent the induction of manganese-superoxide dismutase by paraquat. Under anaerobic conditions, CCl4 and paraquat exhibited no effect on E. coli. In the presence of Mn(II) and paraquat, intracellular superoxide dismutase was markedly induced and protected E. coli against the toxicity of CCl4 and paraquat. The reactive free radical CCl3OO-, which can be formed from the reaction of O2- with CCl4, may cause cell damage. The growth-inhibiting effects of polyhalides in the presence of paraquat followed the order CBrCl3 greater than CCl4 greater than CHCl3 greater than CH2Cl2, which is in accord with that of the reaction rates of these compounds with O2- and with their hepatotoxicities. These results suggest that O2- plays a role in the hepatotoxicity of polyhalides.

Highlights

Presence of Mn(I1) and paraquat, intracellular super- glycerol, and 1 mg/ml MgS04.7H20
Cultures were grown for 22 h, oxide dismutase was markedly induced and protected E. coli against thetoxicity of CC14 and paraquat
The reactive free radical cc1300',which can be formed harvested at 20,000 X g for 5 min at 4 'C, washed three times with 50 mM potassium phosphate, 0.1 mM EDTA, and suspended in 0.5-2.0 ml of this buffer

Summary

Carbon Tetrachloride Toxicity on Escherichia coli Exacerbated by Superoxide*

The effects of carbon tetrachloride(CC14)and para- bath shaker at 100 rpm witha ratio of flask volumeto culture volume quat on the growth of Escherichia coli were investigated. Paraquat at 10 mM caused some inhibition of growth of E. coli in trypticase-soy-yeastextract medium. CC14 hadno effect ongrowthrate oron surviving cell numbers at stationary phase. Trypticase-soynotpreventtheinductionofmanganese-superoxide yeast extract (TSY)' medium contained 3% trypticase soy broth and dismutase byparaquat.Underanaerobicconditions, 0.5%yeast extract,both from Difco. Cultures were grown for 22 h, oxide dismutase was markedly induced and protected E. coli against thetoxicity of CC14 and paraquat. The growth-inhibiting effects of polyhalides catalase activitieswere assayed as previously described (26).Protein in the presence of paraquat followed the orCdeBrrC13 was estimated by the Lowryprocedure (27), withbovineserum. Superoxide dismutase isozymews ere of the reactionrates of these compoundswith 0; and separated hy electrophoresison polyacrylamide gels (28) and were with their hepatotoxicities.

RESULTS

MATERIALS AND METHODS

Generation time

DISCUSSION