# ENTEROTOXIN B PRODUCTION IN STAPHYLOCOCCUS AUREUS

> **NIH NIH R01** · UNIVERSITY OF PITTSBURGH AT PITTSBURGH · 1988 · $124,258

## Abstract

This proposal involves studies on the molecular mechanism of enterotoxin B
production and its regulation in Staphylococcus aureus.  Staphylococcal
enterotoxins are exoproteins that are involved in its pathogenicity and are
causative agents of staphylococcal food-poisoning.  Genetic studies have
suggested that the enterotoxin B gene (entB) may be part of a mobile
genetic element.  We have cloned the entB gene from S. aureus
food-poisoning isolate, strain S6, and determined its nucleotide sequence.
Subcloning and in vitro deletion experiments will be carried out in S.
aureus using the cloned entB gene to identify the involvement of a
positively-acting regulatory gene (entB) in toxin production.  Northern
hybridization analysis and nuclease S1 mapping experiments will be carried
out to determine the transcriptional start and stop sites of the entB and
entR (if any) genes.  These results will also indicate if the entB gene is
regulated at the level of transcription.  There is a more than 100-fold
difference between the amount of enterotoxin B produced by different S.
aureus strains.  We have cloned the entB gene from the high toxin-producer
strain S6.  The entB gene will also be cloned from two low-producer
strains.  The amount of toxin and entB mRNA produced by clones carrying the
entB gene from high and low producer strains in the same host background
will be compared by SDS-polyacrylamide gel electrophoresis followed by
immunoblotting and Northern blot analysis.  The nucleotide sequence of the
promoter region of the entB gene from the low toxin-producer strains will
be determined and compared with the corresponding sequence from strain S6.
These experiments are likely to identify the molecular basis of the
variation in the amount of toxin produced by various strains.  A
positively-acting element, agr, that regulates the production of
exoproteins in S. aureus has been identified.  The cloned entB gene will be
transferred into an agr- strain to determine if the agr element also
regulates enterotoxin B synthesis.  Southern hybridization experiments will
be carried out to determine if the entB gene is part of a discrete genetic
element.  Genetic and biochemical experiments will also be carried out to
determine if the entB gene is part of a phage or a transposon.  A
successful completion of our studies could reveal the molecular mechanism
of enterotoxin B production and its regulation in S. aureus.

## Key facts

- **NIH application ID:** 3129203
- **Project number:** 5R01AI019783-07
- **Recipient organization:** UNIVERSITY OF PITTSBURGH AT PITTSBURGH
- **SAM.gov UEI:** MKAGLD59JRL1
- **Principal Investigator:** SALEEM A. KHAN
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1988
- **Award amount:** $124,258
- **Award type:** 5
- **Project period:** 1982-08-01 → 1990-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3129203

## Citation

> US National Institutes of Health, RePORTER application 3129203, ENTEROTOXIN B PRODUCTION IN STAPHYLOCOCCUS AUREUS (5R01AI019783-07). Retrieved via MORVS 2026-10-24 from https://api.morvs.ai/grant/nih/3129203. Licensed CC0.

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