# IRON UPTAKE AS A VIRULENCE FACTOR IN PATHOGENIC VIBRIOS

> **NIH NIH R01** · OREGON HEALTH & SCIENCE UNIVERSITY · 1987 · $134,719

## Abstract

The long term objective of this research is to investigate the genetics and
molecular biology of a virulence-associated property, plasmid-mediated iron
uptake, which plays an important role in the pathogenesis of many invasive
septicemic diseases of man and domestic animals.  We are presently using as
a model system the fish pathogen Vibrio anguillarum which causes a terminal
hemorrhagic septicemia.  The features of the plasmid-mediated virulence
determinant makes it a very attactive model to study host bacterial
interacions.  We have used transposition mutagenesis, molecular cloning and
DNA sequencing to define at least four components of the pJM1
plasmid-mediated iron uptake system:  a siderophore; a receptor for
iron-siderophore complexes which is the 86 kd outer membrane protein OM2; a
regulatory trans-acting factor and RSV1 repeated sequences that flank the
iron uptake region in the pJM1 plasmid.  The specific roles that each of
these four components play in the regulation of the iron uptake process and
virulence in V. anguillarum will be elucidated by the proposed
investigation.  The specific aims to achieve these objectives are:  1.
Isolation and structure determination of the V. anguillarum siderophore.
2. Complementation analysis of cloned pJM1 iron uptake regions.  3.
Characterization of the cloned OM2 protein gene.  4. Cloning and
characterization of the trans-acting regulatory factor that enhances the
production of siderophore activity.  5. Investigation of the nature of the
increased siderophore production and high iron uptake proficiency of a V.
anguillarum isolate and its relationship to the tandem duplication of one
of the two repeated sequences flanking the pJM1 iron uptake region.
Repeated sequences identified as IS1-like elements, flank the iron uptake
region of another virulence associated plasmid, pCo1V-K30, found in human
invasive strins of Escherichia coli.  The iron uptake genes within the
region flanked by the repeated sequences appeared to be very conserved in
both the pCo1V-K30 and the pJM1 plasmids, as well as in other plasmids and
chromosomes.  The existence of the repeated sequences bracketing these
virulence determinants may have contributed to their recombinational
mobility.  Thus, this project will not only elucidate the role of iron
uptake in the pathogenesis of invasive bacterial disease, but will also
contribute to the understanding of the mechanisms by which these virulence
factors have spread epidemiologically in nature.

## Key facts

- **NIH application ID:** 3128433
- **Project number:** 5R01AI019018-06
- **Recipient organization:** OREGON HEALTH & SCIENCE UNIVERSITY
- **SAM.gov UEI:** NPSNT86JKN51
- **Principal Investigator:** JORGE H CROSA
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1987
- **Award amount:** $134,719
- **Award type:** 5
- **Project period:** 1982-04-01 → 1990-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3128433

## Citation

> US National Institutes of Health, RePORTER application 3128433, IRON UPTAKE AS A VIRULENCE FACTOR IN PATHOGENIC VIBRIOS (5R01AI019018-06). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3128433. Licensed CC0.

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