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Microbial
Development
Overview
Our Laboratory positions itself in the analysis of spore development in B. subtilis. Two important lines of work deal with the study of checkpoint mechanisms, and the control of cellular morphogenesis. Specifically, we are interested in the study of two checkpoints, one linking chromosome segregation to asymmetric cell division at the onset of sporulation, and the other coupling the activation of the late prespore-specific transcription regulator SigG to the complete engulfment of the prespore by the mother cell.Activation of SigG following engulfment completion triggers the morphogenesis of the main protective structures of the spore. The outermost of these structures is the spore coat, formed by the ordered assembly of over 30 protein components. Proper assembly of the spore coat requires strict control over the time of synthesis of the coat proteins, and the action of a unique class of morphogenetic proteins that guide the assembly of the structural components. It also depends on various post-translational modifications that enforce the correct order of interactions among the structural components. Coat biogenesis is a model system for the assembly of complex multiprotein structures during a developmental process, but it also allows the study of the mechanisms by which proteins or protein assemblies are targeted to specific sub-cellular locations, in this case to the surface of the developing spore.
The identification of domains of coat proteins that contain the determinants for assembly, permits the construction of chimaeras for the display of enzymes or heterologous antigens at the spore surface. One Project in course deals with the use of Bacillus subtilis spores (non-pathogenic) for the display of subunits of the anthrax toxins, and the potential use of the recombinant spores as vaccines. Another example of a more applied Project, stems from the observation that spores of a Laboratory (domesticated) strain of B. subtilis given to newly hatched chicks can suppress all aspects of late infection with Salmonella. With this in mind, we have isolated a large collection of aerobic sporeforming bacteria associated with the gastrointestinal tract of various animals. We found undomesticated isolates of Bacillus subtilis to differ greatly from the Laboratory strains currently in use, and to produce a wide array of antimicrobial compounds, including several with bacteriolytic activity against important pathogens.
Group leader:
Adriano O.
Henriques, PhD
Contact:
Instituto de Tecnologia Química e BiológicaUniversidade Nova de Lisboa
Av. da República, Apartado 127
2781-901 Oeiras
PORTUGAL
Telephone: +351 21 446 9521
FAX: +351 21 441 1277
E-mail: aoh@itqb.unl.pt
URL: www.itqb.unl.pt/Research/Biology/Microbial_Development