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Toxin Production and Secretion by Clostridium difficile
My laboratory has been studying the control of the synthesis and
release of the cytotoxin from Clostridium difficile into
the surrounding medium. We have noted that the toxin is produced
and released into the medium sooner when the culture is grown from
an initial pH of 8.5. This also enhances the fermentation of mannitol.
- Kazamias, M.T. and J.F. Sperry. 1995.
Enhanced fermentation of mannitol and release of cytotoxin by
Clostridium difficile in alkaline culture media.
Appl.Environ.Microbiol. 61:2425-2427.
- Osgood, D.P., N.P. Wood, and J.F. Sperry.
1993. Nutritional aspects of cytotoxin production by Clostridium
difficile. Appl.Environ. Microbiol. 59:3985-3988.
Detection
and Identification of Bacteria by Spectroscopy
My laboratory and
that of Professor Wilfred Nelson in the Chemistry Department have
been collaborating of research concerning the detection and identification
of microorganisms using resonance Raman spectroscopy. When bacteria,
viruses or any living organism is excited with a laser turned to
the ultraviolet range, this produces a characteristic spectrum that
is due mostly to nucleotide bases and somewhat to aromatic amino
acids. This method of detection is extremely sensitive, requiring
only a few bacteria to give a representative spectrum.
- Manoharan, R, E. Ghiamati, S. Chadha,
W.H. Nelson, W.L. Petacolas, and J.F.
Sperry. 1993. The effect of cultural conditions on deep UV resonance
raman
spectra of bacteria. Appl. Spectros. 47:2145.
- Chadha, S., W.H. Nelson, and J.F. Sperry.
1993. Ultraviolet micro-raman spectrograph
for the detection of small numbers of bacterial cells.
Rev. Sci. Instrum. 64:3088.
- Chadha, S., R. Manoharan, P. Moenne-Loccoz,
W.H. Nelson, W.L. Petacolas and J.F. Sperry. 1993. Comparison
of the UV resonance raman spectra of bacteria, bacterial cell
walls and ribosomes excited in the deep UV. Appl. Spectros. 47:38-43.
- Nelson, W.H., and J.F. Sperry. 1991.
UV resonance raman spectroscopic detection and identification
of bacteria and other microorganisms p. 97-143.
In Modern Techniques for Rapid Microbiological Analysis,
W.H. Nelson Ed., VCH Publishers, Inc., New York, NY.
- Wu, Q., W.H. Nelson, S. Elliott, J.F.
Sperry, M. Wu, C. Chen, M.S.Feld, R. Desari, and
M. Manoharan. 1999. UV Raman spectral cross-sections of E.
coli excited 299-257nm. (Pittsburgh Conference Analyt. chem.
appl. Spectros.)
Biosensors
for Rapid Detection of Food Quality and Safety
My laboratory
has also been involved in the detection and identification of pathogenic
bacteria in foods. We have been exploring the use of specific antibody-coated
glass beads to capture specific bacteria and detect their presence
using resonance Raman
spectroscopy.
- Pivarnik, P., J.F. Sperry, C.W. Brown,
S.V. Letcher, A.G. Senegal, and A.G. Rand1997.
Detection of Staphylococcus aureus using an enhanced chemiluminescent
biosensor. (IAFES)
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