Effect of penicillin on fatty acid synthesis and excretion in Streptococcus mutans BHT
Treatment of exponentially growing cultures of Streptococcus mutans BHT with growth-inhibitory concentrations (0.2 microgram/ml) of benzylpenicillin stimulates the incorporation of (2-/sup 14/C) acetate into lipids excreted by the cells by as much as 69-fold, but does not change the amount of /sup 14/C incorporated into intracellular lipids. At this concentration of penicillin cellular lysis does not occur. The radioactive label is incorporated exclusively into the fatty acid moieties of the glycerolipids. During a 4-hr incubation in the presence of penicillin, the extracellular fatty acid ester concentration increases 1.5 fold, even though there is no growth or cellular lysis. An indication of the relative rate of fatty acid synthesis was most readily obtained by placing S. mutans BHT in a buffer containing /sup 14/C-acetate. Under these nongrowing conditions free fatty acids are the only lipids labeled, a factor which simplifies the assay. The addition of glycerol to the buffer causes all of the nonesterified fatty acids to be incorporated into glycerolipid. The cells excrete much of the lipid whether glycerol is present or not. Addition of penicillin to the nongrowth supporting buffer system does not stimulate the incorporation of (/sup 14/C)-acetate into fatty acids.
- Research Organization:
- Temple Univ. School of Medicine, Philadelphia, PA
- OSTI ID:
- 5179903
- Journal Information:
- Lipids; (United States), Vol. 3
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CARBOXYLIC ACIDS
BIOSYNTHESIS
PENICILLIN
BIOLOGICAL EFFECTS
ACETATES
BIOCHEMICAL REACTION KINETICS
CARBON 14 COMPOUNDS
LIPIDS
STREPTOCOCCUS
ANTI-INFECTIVE AGENTS
ANTIBIOTICS
BACTERIA
CARBOXYLIC ACID SALTS
DRUGS
KINETICS
LABELLED COMPOUNDS
MICROORGANISMS
ORGANIC ACIDS
ORGANIC COMPOUNDS
REACTION KINETICS
SYNTHESIS
550201* - Biochemistry- Tracer Techniques