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Category: Bacterial Pathogenesis
Bacillus subtilis Systems Biology: Applications of -Omics Techniques to the Study of Endospore Formation, Page 1 of 2
< Previous page | Next page > /docserver/preview/fulltext/10.1128/9781555819323/9781555816759_Chap06-1.gif /docserver/preview/fulltext/10.1128/9781555819323/9781555816759_Chap06-2.gifAbstract:
The principal B. subtilis laboratory strain, strain 168, is derived from a parent strain isolated in Marburg, Germany, following a mutagenesis procedure ( 1 ). The popularity of this strain arose after it was shown to be competent for genetic transformation ( 2 , 3 ), which paved the way for myriad molecular genetics analyses that led to a detailed understanding of the biology of B. subtilis and related Gram-positive bacteria. It is therefore not surprising that strain 168 was the first Gram-positive species to have its entire genome sequenced, at a time when sequencing was a laborious and expensive process. The project to sequence the genome was set up in 1987 by a consortium of over 30 laboratories and took about 10 years to complete. Each laboratory was assigned a different region of the chromosome and used their own cloning and sequencing strategies to manage their assigned portion of the genome ( 4 ). The final genome sequence contained 4,214,810 base pairs, and the original annotation included 4,100 protein-coding genes ( 5 ). Following the development of sequencing technologies that were considerably faster and more efficient, the genome of B. subtilis strain 168 was resequenced and cleared of sequencing errors in 2009 ( 6 ). The most recent update of the annotation brought the total of protein-coding genes to 4,458 ( 7 ).
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The life cycle of B. subtilis and the principal stages of sporulation. During the first stage of sporulation, the master regulator Spo0A∼P is required in combination with σA (major σ factor) and σH (stationary phase σ factor) for the expression of early sporulation genes. Next, an asymmetric division of the sporulating cell creates the mother cell (light blue) and the forespore (orange). Each compartment establishes cell-specific lines of gene expression driven by σF in the forespore and σE in the mother cell. Subsequently, the mother cell engulfs the forespore. During engulfment, proteins produced in the mother cell assemble at the forespore surface to form the coat (dark red). After engulfment, σG substitutes for σF and σK replaces σE (σA remains active during the entire process). The cortex (yellow), made of peptidoglycan, is assembled between the inner and outer forespore membranes. Once the spore is mature, the mother cell lyses. During the germination process, the cortex is hydrolyzed and the coat is shed. Adapted from references 27 , 32 , and 104 .
The life cycle of B. subtilis and the principal stages of sporulation. During the first stage of sporulation, the master regulator Spo0A∼P is required in combination with σA (major σ factor) and σH (stationary phase σ factor) for the expression of early sporulation genes. Next, an asymmetric division of the sporulating cell creates the mother cell (light blue) and the forespore (orange). Each compartment establishes cell-specific lines of gene expression driven by σF in the forespore and σE in the mother cell. Subsequently, the mother cell engulfs the forespore. During engulfment, proteins produced in the mother cell assemble at the forespore surface to form the coat (dark red). After engulfment, σG substitutes for σF and σK replaces σE (σA remains active during the entire process). The cortex (yellow), made of peptidoglycan, is assembled between the inner and outer forespore membranes. Once the spore is mature, the mother cell lyses. During the germination process, the cortex is hydrolyzed and the coat is shed. Adapted from references 27 , 32 , and 104 .