AbstractsBiology & Animal Science

Endospores are dormant, multilayered, highly resistant cellular structures formed in response to stress by certain bacteria belonging to the genera Bacillus, Clostridium and other related organisms. In presence of nutrients and favorable conditions spores germinate and grow out as normal vegetative cells. Since certain species of Bacilli and Clostridia are pathogenic as well as potential food spoilers the detailed study of spore resistance mechanisms is of high relevance. The surface layes of spores - coat and exosporium - are made of proteins that in part contribute to the resistance behaviour of spores. About 30% of the proteins make up an insoluble fraction, characterized by interprotein cross-links, which is resistant to alkalis, chemicals and proteolytic enzymes. In this thesis a method allowing the study of the insoluble protein fractrion is presented. Effect of deletion of only certain protein genes on the resistive nature of spores is discussed. Importantly the role of interprotein cross-linking in the maturation of spores, their resistant nature and likely in germination behaviour is studied. A detailed bioinformatic analysis of surface layer proteins indicates the importance of the protein sequence, structure and other physical properties to the integrity of spores. The identification and quantification of proteins involved in spore maturation has contributed to new insights with respect to their functions, abundances and nature of inter-protein cross-links. Further research on spores is required to gain more detailed molecular information on sporulation of bacteria, spore layer assembling and spore maturation as well as spore germination.