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CATALASE AND SUPEROXIDE DISMUTASE OF ROOT-COLONIZING SAPROPHYTIC FLUORESCENT PSEUDOMONADS
Citation:
Katsuwon, J. AND A. Anderson. CATALASE AND SUPEROXIDE DISMUTASE OF ROOT-COLONIZING SAPROPHYTIC FLUORESCENT PSEUDOMONADS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-93/220.
Description:
Root-colonizing, saprophytic fluorescent pseudomonads of the Pseudomonas putida-P. fluorescens group express similar levels of catalase and superoxide dismutase activities during growth on a sucrose- and amino acid-rich medium. ncreased specific activities of catalase but not superoxide dismutase were observed during growth of these bacteria on components washed from root surfaces. he specific activities of both enzymes were also regulated during contact of these bacteria with intact bean roots. ncreased superoxide dismutase and decreased catalase activities were observed rapidly, by 10 min upon inoculation of cells onto intact bean roots. atalase specific activity increased with time to peak at 12 h before declining. y 48 h. the cells displayed this low catalase but maintained high superoxide dismutase specific activities. atalase with a low specific activity and a high superoxide dismutase activity also were present in extracts of cells obtained from 7-day-old root colonized from inoculum applied to seed. his specific activity of superoxide dismutase of root-contacted cells was about four-fold higher in comparison to cells grown on rich medium, whereas the specific activity for catalase was reduced about fivefold. ingle catalase isozyme, isozyme A, and one isozyme of superoxide dismutase, isozyme 1. were detected during growth of the bacteria on root surface components and during exposure of cells to intact bean roots for 1 h. An additional catalase. isozyme B. was detected from bacteria after exposure to the intact bean roots for 12 h. Catalase isozyme A, and superoxide dismutase isozyme 1 were located in the cytoplasm and catalase band B was located in the membrane of P.putida.