"A La Recherche" of functions for the spore protein SASP-E from Bacillus subtilis

We previously observed that Bacillus subtilis spores from sspE mutants presented a lower germination capacity in media containing high salt concentrations (0. 9 M NaCl). This deficiency was attributed to the absence of SASP-E (gamma-type small-acid-soluble protein), rich in osmocompatible amino acid...

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Autores principales: Ruzal, S.M., Bustos, P.L., Sánchez-Rivas, C.
Formato: JOUR
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Acceso en línea:http://hdl.handle.net/20.500.12110/paper_10177825_v23_n1_p15_Ruzal
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Sumario:We previously observed that Bacillus subtilis spores from sspE mutants presented a lower germination capacity in media containing high salt concentrations (0. 9 M NaCl). This deficiency was attributed to the absence of SASP-E (gamma-type small-acid-soluble protein), rich in osmocompatible amino acids released by degradation. Herein we observed that, in addition, this mutant spore presented a reduced capacity to use L-alanine as germinant (L-ala pathway), required longer times to germinate in calcium dipicolinate (Ca2+-DPA), but germinated well in asparagine, glucose, fructose, and potassium chloride (AGFK pathway). Moreover, mild sonic treatment of mutant spores partially recovered their germination capacity in L-ala. Spore qualities were also altered, since sporulating colonies from the sspE mutant showed a pale brownish color, a higher adherence to agar plates, and lower auto-fluorescence, properties related to their spore coat content. Furthermore, biochemical analysis showed a reduced partition in hexadecane and a higher content of Ca2+-DPA when compared with its isogenic wild-type control. Coat protein preparations showed a different electrophoretic pattern, in particular when detected with antibodies against CotG and CotE. The complementation with a wild-type sspE gene in a plasmid allowed for recovering the wild-type coat phenotype. This is the first report of a direct involvement of SASP-E in the spore coat assembly during the differentiation program of sporulation. © the Korean Society for Microbiology and Biotechnology.