# GENETIC SYSTEMS TO STUDY VIRULENCE IN BACTEROIDES

> **NIH NIH R01** · TUFTS UNIVERSITY BOSTON · 1987 · $197,320

## Abstract

Bacteroids fragilis is an important human pathogen.  Attempts to evaluate
and investigate determinants that may contribute to the virulence of this
organism have been hampered by the absence of suitable systems of genetic
analysis.  We propose to continue the development of genetic systems in
this organism with two specific aims.  To investigate the determinants of
antibiotic resistance and their transfer within B. fragilis and from B.
fragilis to E. coli.  We will characterize pBFTM10, a 15 kb transfer factor
that encodes Clnr in B. fragilis and Tetr in E. coli.  These resistances
are carried on a transposon, Tn4400, that functions in E. coli.  Studies
are described to determine the transposition properties of this element and
the IS elements which are present as direct repeats at each end.  Studies
will be directed towards understanding the "tetracycline transfer factor"
that promotes plasmid and transposon transfer between B. fragilis strains
and into E. coli.  The second aspect of our proposal is to develop a
genetic system to analyze virulence factors in B. fragilis.  This will
involve isolating mutants of selected phenotypic characteristics and then
isolating the gene(s) encoding the determinants by making use of a
chromosome library of B. fragilis cloned in E. coli.  Tn4400 will be
employed as a mutagen in B. fragilis to help locate chromosomal genes
suspected to be virulence factors.  The determinants to be investigated are
imipenem and tetracycline resistance, catalase production and neuraminidase
production.  The beta-lactamase that inactivates imipenem will be studied
first.  The genes encoding tetracycline resistance in B. fragilis will be
studied and we will attempt to develop a probe to study the mechanism of
Tetr transfer.  The role of catalase in the ability of B. fragilis to
survive in oxygenated tissue will be assessed.  Finally, the role that
neuraminidase plays in tissue destruction during B. fragilis infections
will be investigated.  Once the mutants have been isolated and the gene(s)
encoding the determinant are located then important questions related to
expression can be addressed.  The results of these studies should give a
clearer picture of how DNA is transferred in B. fragilis and help to
provide a genetic system to study virulence factors in this important
pathogen.

## Key facts

- **NIH application ID:** 3128853
- **Project number:** 5R01AI019497-05
- **Recipient organization:** TUFTS UNIVERSITY BOSTON
- **SAM.gov UEI:** C1F5LNUF7W86
- **Principal Investigator:** MICHAEL H MALAMY
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1987
- **Award amount:** $197,320
- **Award type:** 5
- **Project period:** 1983-01-01 → 1989-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3128853

## Citation

> US National Institutes of Health, RePORTER application 3128853, GENETIC SYSTEMS TO STUDY VIRULENCE IN BACTEROIDES (5R01AI019497-05). Retrieved via MORVS 2026-10-24 from https://api.morvs.ai/grant/nih/3128853. Licensed CC0.

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