Differentiation of Rhizobium japonicum, III. Inhibition of Nitrogenase Derepression by Chloramphenicol and Rifampicin Concentrations, Not Inhibiting Growth

Abstract

Development of nitrogenase (40-140 nmol C2H4 · mg protein−1·h−1) in Rhizobium japonicum 61-A-101 after transfer to special culture conditions (medium 20 P, 2% O2, 10% CO2, 88% N2 in the gas phase) is inhibited by chloramphenicol (6×10−4-10−3M) and by rifampicin (10−5M). These concentrations do not inhibit the slow growth of the cells under these conditions with a doubling time of the cell protein and living cell number of 3 — 5 d. Nitrogenase activity of previously derepressed cells is not inhibited by chloramphenicol. Growth of the cells under air in yeast extract-mannitol-glycerol medium (8 h doubling time) is affected significantly more by chloramphenicol (2.5 × 10−4M) than growth under nitrogenase derepressed culture conditions. © 1978, Walter de Gruyter. All rights reserved.