Kinetics of Utilization of Organic Compounds in the Growth ofMycobacterium tuberculosis

Abstract

AND WILLIA SEGAL. Kinetics of utilization of organic compounds in the growth of Mycobacterium tuberculosis. J. BACTERIOL. 90:157-163. 1965.-To obtain a workable system for a study of the kinetics of nutrient utilization (based on specific quantitative assay) by Mycobacterium tuberculosis, several cultural refinements were introduced: the use of shake culture, a 40-fold increase in the size of inoculum, substitution of glutamate for asparagine as nitrogen source, and elimination of glucose from the medium with glycerol remaining as carbon source. These modifications resulted in reduction to a tenth of the lag phase of glycerol utilization (from 40 to 4 days), and in a greatly increased rate of growth. Both coordinate and sequential patterns of nutrient utilization were in evidence, except in the case of citrate, which was never utilized under a variety of conditions of culture. The coordinate pattern of glucose-glutamate and glucose-glycerol utilization would appear to rule out catabolite repression by glucose. However, elimination of glucose from the medium resulted in elimination of the 4-day lag period before glutamate utilization was initiated, leaving open to question the role of glucose in this system. Evidence is presented for the hypothesis that the sequential pattern of glutamate-glycerol utilization is a function of glutamate repression of glycerol oxidation in the growth of M. tuberculosis, although no diauxie effect is apparent. In a determination of which nutrient-utilization systems were regulated by induction, only in the case of glycerol was evidence obtained for an inducible system. The enzymatic mechanisms underlying these patterns of nutrient utilization are presently being investigated.

Dynamic exometabolome analysis reveals active metabolic pathways in non‐replicating mycobacteria

“…The label propagation dynamics demonstrated that succinate was exclusively derived from isocitrate through the glyoxylate shunt enzyme isocitrate lyase, encoded by two isoenzymes ( icl1 , MSMEG_0911 and icl2 , MSMEG_3706). This finding is consistent with increased isocitrate lyase expression and enzymatic activity during the transition to hypoxia (Wayne and Lin, ; Shi et al ., ), but extracellular citrate is an unexpected substrate because it does not support aerobic growth of mycobacteria (Bowles and Segal, ).…”

The effects of isoniazid on the carbohydrates of Mycobacterium tuberculosis BCG

“…It must further be assumed that, when glycerol is not the sole carbon source in the medium, the regulatory situation as far as its uptake is concerned is somewhat different, so that no decrease in uptake follows the accumulation of intermediates. Evidence exists for regulatory control over glycerol uptake in E8cherichia coli (Sanno, Wilson & Lin, 1968) and in Mycobacterium phlei (Bowles & Segal, 1965). Further analysis of the situation on the basis of present evidence would be highly speculative.…”

Iron transport in Mycobacterium smegmatis: Uptake of iron from ferric citrate.

“…Although glycerol is most commonly used as the sole carbon source for mycobacterial cultures, many medium preparations also contain a significant amount of citrate (8,13,15,20). However, Bowles and Segal (6) found that citrate was not used by M. tuberculosis, nor did it have any effect on the utilization of other nutrients: glucose, glutamate, asparagine, or glycerol. Citrate could though have a role in iron metabolism in the mycobacteria and could therefore have a bearing on their growth in laboratory media as well as on their pathogenicity.…”