[A new experimental approach to the search for chemical density factors in the regulation of microbial population growth].
The feedback level (FBL) in growth regulation has been determined in the experiments on Escherichia coli O-124 on the basis of the theory developed by Degermendzhy et al (1989). FBL is here determined as a function of variations in growth acceleration caused by discrete decrease in bacterium concentration, the medium chemical composition being preserved. It estimates by integration regular action of all chemical density factors. FBL has been determined on periodic cultivation with glucose. In various phases of growth the native culture was diluted with a filtrate of its own. As the sample had grown up, variations in growth acceleration were calculated against the reference specimens. The value of FBL was definitely anything but zero at the end of the experimental phase and in the phase of growth deceleration, and it was equal to -20 divided by -200 (h.g/l). The feedback component was also calculated from the obtained dependence of the growth rate on the glucose concentration. It amounted to mumax = 0.55 +/- 0.05 h-1, Ks = 2.5 +/- 0.7 mg/l. Regulation relative to glucose was 0.5-40% of FBL. This indicates that there are other regulators of growth. Being sufficiently accurate, the new method may supplement microbiological means of determining the growth regulating cell-density factors.
A G
AG
Degermendzhi
V V
VV
Adamovich
V a
Va
Adamovich
D004926:Escherichia coli / Q000254:growth & development*; D005246:Feedback; D006133:Growth Substances / Q000502:physiology*
D006133:Growth Substances