# PHYSIOLOGIC CHARACTERISTICS OF TREPONEMA PALLIDUM

> **NIH NIH R01** · UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON · 1991 · $132,672

## Abstract

Treponema pallidum subsp.  pallidum and related organisms are
helically- shaped bacteria which cause venereal syphilis, endemic
syphilis, yaws and pinta in humans.  Although the incidence of
sexually transmitted diseases would be expected to decrease with
changing sexual behavior as a result of the AIDS epidemic, the
number of reported primary and secondary syphilis cases in the
United States increased 30% in 1987, due primarily to apparent
epidemics in New York, Florida, and California.  Further
understanding of T. pallidum is needed to aid in the prevention,
diagnosis, and treatment of syphilis.  In the proposed research,
we will continue studies on the physiology, structure, and
antimicrobial susceptibility of T. pallidum.  The principal focus
will be efforts to continuously culture T pallidum in vitro, using
as a starting point a tissue culture system which supports 20- to
100-fold multiplication of the organism over a 12 to 15 day period
of incubation.  Mammalian cells, in particular Sf1Ep cottontail
rabbit epithelial cells, are required for the in vitro
multiplication of T. pallidum in this system, but recent studies
indicate that rapid growth or high metabolic rates of these cells
inhibit treponemal multiplication.  Furthermore, removal of amino
acids and vitamins from the culture medium enhances the
multiplication of T. pallidum, apparently by inhibiting the growth
and metabolism of the tissue culture cells.  In the coming grant
period, conditions inhibitory to mammalian cell metabolism,
including irradiation, addition of cycloheximide, and use of
nutrient-deficient media, will be tested for their ability to
enhance the multiplication of T. pallidum If conditions are
identified which significantly increase and prolong treponemal
growth, they will be combined with subculture or medium replacement
techniques in an attempt to produce continuous growth.  Through the
deletion of medium components, dialysis of serum, and removal of
tissue extract, it should be possible to define the nutritional
requirements of T pallidum.  In addition, the biosynthetic capacity
of T. pallidum will be assessed by measuring the incorporation of
radiolabelled D-glucose, fatty acids, and inorganic salts into
proteins, nucleic acids, and lipids.  To assess the antimicrobial
susceptibility pattern of T. pallidum, the in vitro culture system
will be utilized to determine the minimal inhibitory and
bactericidal concentrations of a variety antimicrobial agents
against the Nichols strain and other pathogenic strains.  In our
continuing studies of the major structural elements of T. pallidum,
we will attempt to purify and characterize the outer membrane,
cytoplasmic membrane, and cytoplasmic fibrils of pallidum using
isoelectric focusing, hydrophobic interaction chromatography,
sucrose gradient sedimentation, and other methods.  Immunoelectron
microscopy of ultrathin sections will be used to localize both
internal and external proteins in the overall structural studies
wi...

## Key facts

- **NIH application ID:** 3129474
- **Project number:** 5R01AI020006-08
- **Recipient organization:** UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON
- **SAM.gov UEI:** ZUFBNVZ587D4
- **Principal Investigator:** STEVEN J. NORRIS
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1991
- **Award amount:** $132,672
- **Award type:** 5
- **Project period:** 1982-08-01 → 1993-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3129474

## Citation

> US National Institutes of Health, RePORTER application 3129474, PHYSIOLOGIC CHARACTERISTICS OF TREPONEMA PALLIDUM (5R01AI020006-08). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3129474. Licensed CC0.

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