abstract book - Clostridia

DISTRIBUTION OF PUTATIVE SPORE GERMINATION GENES INCLOSTRIDIUM SPECIESY. Xiao 1 , A. Wagendorp 2 , C. Francke 3 , T. Abee 1 , M. Wells-Bennik 21Food microbiology laboratory, Wageningen University, Wageningen 6700EV, Netherlands. 2 NIZO food research, Ede 6710 BA, Netherlands. 3 CMBINCMLS, Radboud University Nijmegen Medical Centre, Nijmegen 6500 HB,NetherlandsSurvival and persistence of Bacilli and Clostridia in the environment largelydepends on their ability to produce spores which can germinate underfavorable conditions. The process of spore germination is best understood inBacilli. When a dormant spore senses an environment that can support thesurvival of a vegetative cell, germination of spores can be induced.Germination in response to nutrients is believed to be mediated by receptorsthat reside in the inner spore membrane, which are encoded by tricistronicso-called ger operons. Whereas ger family members are found in Bacillusand most Clostridia, the numbers of ger operons in Bacillus species tend tobe higher than those found in Clostridia. Upon triggering of germinationthrough the Ger receptor, full germination requires the removal of the sporecortex.Hydrolysis of the cortex in the genus Bacillus is likely performed bygermination-specific cortex-lytic enzymes. Several of these cortex lyticenzymes from bacilli and clostridium have been characterized. In thepresent study, the occurrence of known and putative Bacillus germinationrelatedgenes in their anaerobic relatives was analyzed by a homologysearch of 34 sequenced Bacillus genomes and 24 Clostridium genomes.The presence of the various genes involved in germination in variousspecies will be discussed, with a particular focus on the Clostridia.