Effect of the growth environment on cell-envelope components of Escherichia coli in relation to sensitivity to human serum

Abstract

SUMMARY.Three smooth strains of urinary Escherichia coli were grown in a chemostat under carbon-limited (C-lim) and magnesium-limited (Mg-lim) conditions over a range of dilution rates (D). Strain LP1674 was resistant to human serum under C-lim but became sensitive when grown under Mg-lim, the degree of sensitivity increasing as D increased. The transition to serum sensitivity was accompanied by loss of ability to produce extractable K1 antigen and a reduction in the amount of a 46k envelope polypeptide. C-lim cells of strain LP729 exhibited a delayed sensitive response to serum, the degree of lag in serum killing becoming less pronounced with increasing values of D; Mg-lim cells were more sensitive with little or no lag in serum killing. The degree of lag appeared to be directly related to the amount of the 0 side-chain sugar mannose associated with the lipopolysaccharide. C-lim and Mg-lim cultures of E. coli strain LP1395 were resistant to serum except when growing at near maximal rates. Although C-lim cultures contained more acidic polysaccharide than Mg-lim cells, transition to serum sensitivity did not appear to be related to exopolysaccharide production. Rapidly growing cells of strain LPl395 did, however, have lower lipopolysaccharide 0 side-chain sugar : core-sugar ratios than more slowly growing cells. With all three strains, changes in dilution rate and in the nature of the limiting nutrient were accompanied by changes in envelope protein composition.This study demonstrates that many cell-surface changes occur in response to alterations in the growth environment and some of these may be correlated with changes in sensitivity to serum.

The Role of the O and K Antigens in Determining the Resistance of Klebsiella aerogenes to Serum Killing and Phagocytosis

“…The nutritional environment will greatly affect the composition of the outer envelope of Gram-negative bacteria and therefore the response of the organism to serum (Taylor et al, 1981) and phagocytosis (Finch & Brown, 1978). Sensitivity of Gram-negative bacteria to serum has been shown to vary with a number of factors, including growth rate and the availability of magnesium and carbon (Taylor et al, 1981). The effects of these parameters on phagocytosis have not been extensively explored.…”

Induction of complement sensitivity in Escherichia coli by citric acid and low pH

“…This indicates that a possible component of cellular resistance may be due to a reversal of the inhibitory effects of the MAC (Dankert 1989). The same strain became sensitive to the bactericidal action of serum when grown in carbon‐ and magnesium‐limited conditions (Taylor 1978; Taylor et al . 1981).…”

Effects of in vitro Growth Phase on the Pathogenesis of Salmonella typhimurium in Mice

“…There have been many reports over the last 70 years indicating that rapidly growing bacteria are more susceptible to serum, to chemical, osmotic, lysosomal and certain antibiotic agents, as well as to temperature shock than are slower growing bacteria (Sherman & Albus, 1923;Sherman & Cameron, 1934;Rest et al, 1977;Taylor et al, 1981 ;Wilson & Miles, 1964). It has also been reported that the blood clearance of pneumococci can be affected by bacterial growth phase (Brown et al, 1981).…”