Mechanism and site of inhibition of Bacillus cereus spore outgrowth by nitrosothiols
Structure vs. activity studies demonstrate that nitrosothiols inhibit outgrowth of B. cereus spores by reversible covalent bond formation with sensitive spore components. Kinetic studies of the binding of nitrosothiols and iodoacetate, a known sulfhydryl reagent, show that they complete for the same spore sites. Since two other nitrite derivatives, the Perigo factor and the transferrin inhibitor, interfere with iodoacetate label uptake in a kinetically similar fashion, all of these compounds may inhibit spore outgrowth by interacting with the same spore thiol groups. Disruption of spores which have been inhibited by radioactive iodoacetate demonstrates that much of the label is incorporated into a membrane-rich fraction that sediments as a single peak on a sucrose density gradient. SDS gel electrophoresis and autofluorography allows the identification of four intensely labelled proteins with molecular weights of 13,000, 28,000, 29,000, and 30,000. If the iodoacetate labelling is carried out in the presence of nitrosothiol, incorporation is greatly reduced into all components. When germinating spores are labelled with succinate or the lactose analog, o-nitrophenylgalactopyranoside, a significant reduction in the amount of label bound is also observed suggesting that two iodoacetate-reactive sites may be the succinate and lactose permease systems. Severe decreases in the transport of succinate and lactose into iodoacetate and nitrosothiol inhibited spores further implicates a nitrosothiol (iodoacetate) permease interaction. Iodoacetate and nitrosothiols therefore may exert their inhibitory effects by interfering with critical membrane protein sulfhydryl groups, possibly by a a covalent modification mechanism. Some of these sensitive thiols may be involved in active transport processes.
- Research Organization:
- Maryland Univ., College Park (USA)
- OSTI ID:
- 5766625
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
BACILLUS CEREUS
SPORES
IODINE COMPOUNDS
BIOCHEMICAL REACTION KINETICS
TOXICITY
NITROSO COMPOUNDS
GROWTH
ELECTROPHORESIS
EXPERIMENTAL DATA
INHIBITION
METABOLISM
STRUCTURE-ACTIVITY RELATIONSHIPS
THIOLS
TRACER TECHNIQUES
UPTAKE
BACILLUS
BACTERIA
DATA
HALOGEN COMPOUNDS
INFORMATION
ISOTOPE APPLICATIONS
KINETICS
MICROORGANISMS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC SULFUR COMPOUNDS
REACTION KINETICS
560302* - Chemicals Metabolism & Toxicology- Microorganisms- (-1987)
550701 - Microbiology- Tracer Techniques