ISSN:
1750-3841
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
A Clostridium sp. RKD isolated from the intestine of decaying fish, showing 99% sequence identity with Clostridium tetani at a 16S rRNA level, produced a neurotoxin that was neutralized by botulinum antitoxin (A+B+E). It also showed an amplification of near-expected size when polymerase chain reaction (PCR) was performed using group- and type-specific primers for botulinum neurotoxin type B. The isolate exhibited differences with both C. tetani and Clostridium botulinum with respect to phenotypic characteristics and chemotaxo-nomic markers. Spore production was optimized with respect to media composition and stage of growth. Time-dependant examination of sporulation revealed 2.6% to 49.0% spores in the late stationary phase culture when grown in different broth media. A simpler method for spore production and isolation from culture grown in tryptose sulfite cycloserine (TSC)/anaerobic agar sandwich resulted in 〉95% sporulation, which could be purified to near homogeneity by a simple 2-step procedure. Thermal resistance of spores revealed a biphasic inactivation at lower temperatures with D values for linear inactivation varying from 26.6, 8.0, and 4.3 min at 70 °C, 80 °C, and 90 °C, respectively. The z values of 7.86 °C and 10.47 °C were obtained in the linear and tail regions, respectively. The Weibull parameter b values at 70 °C, 80 °C, and 90 °C were 27.38, 3.55, and 0.99, respectively, with a z’ value of 13.869 °C. The shape parameter n at 70 °C, 80 °C, and 90 °C were 0.63, 0.55, 0.45, respectively. Spores produced on 2 different media (cooked meat medium [CMM] and trypticase peptone yeast-extract glucose [TPYG] agar) exhibited differences in heat resistance. The addition of lysozyme (50 jj.g/mL) before heat treatment resulted in increased thermal resistance of spores.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-2621.2005.tb11482.x
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