This Article Full Text Full Text (PDF) Other Versions of this Article: AEM.02587-07v1 74/8/2391    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Copyright Information Books from ASM Press MicrobeWorld Google Scholar Articles by Artin, I. Articles by Rådström, P. PubMed PubMed Citation Articles by Artin, I. Articles by Rådström, P. Agricola Articles by Artin, I. Articles by Rådström, P.

Effects of Carbon Dioxide on Neurotoxin Gene Expression in Nonproteolytic Clostridium botulinum Type E

Ingrid Artin,^1,2,3 Andrew T. Carter,² Elisabet Holst,³ Maria Lövenklev,^1, David R. Mason,² Michael W. Peck,² and Peter Rådström^1*

Applied Microbiology, Lund Institute of Technology, Lund University, SE-221 00 Lund, Sweden,¹ Institute of Food Research, Norwich Research Park, Colney, Norwich NR4 7UA, United Kingdom,² Division of Medical Microbiology, Department of Laboratory Medicine, Lund University, SE-223 62 Lund, Sweden³

Received 16 November 2007/ Accepted 14 February 2008

Carbon dioxide is an antimicrobial gas commonly used in modified atmosphere packaging. In the present study, the effects of carbon dioxide on the growth of and neurotoxin production by nonproteolytic Clostridium botulinum type E were studied during the growth cycle. Quantitative reverse transcription-PCR and an enzyme-linked immunosorbent assay were used to quantify expression of the type E botulinum neurotoxin gene (cntE) and the formation of type E neurotoxin. The expression levels of cntE were similar in two strains, with relative expression peaking in the transition between exponential phase and stationary phase. In stationary phase, cntE mRNA expression declined rapidly. The cntE mRNA half-life was calculated to be approximately 9 minutes. Neurotoxin formation occurred in late exponential phase and stationary phase. High carbon dioxide concentrations delayed growth by increasing the lag time and decreasing the maximum growth rate. The effects of carbon dioxide concentration on relative neurotoxin gene expression and neurotoxin formation were significant. Expression of cntE mRNA and the formation of extracellular neurotoxin were twofold higher with a headspace carbon dioxide concentration of 70% (vol/vol) compared to 10% (vol/vol). This finding sheds a new, cautionary light on the potential risks of botulism associated with the use of modified atmosphere packaging.

Published ahead of print on 29 February 2008.

Present address: SIK—The Swedish Institute for Food and Biotechnology, SE-402 29 Gothenburg, Sweden.