Role of the gerA operon in L-alanine germination of Bacillus licheniformis spores

Løvdal, Irene Stranden
From, Cecilie
Madslien, Elisabeth
Romundset, Kristin Cecilia Saue
Klufterud, Elin
Rosnes, Jan Thomas
Granum, Per Einar
Date Issued
Løvdal, Irene Stranden; From, Cecilie; Madslien, Elisabeth; Romundset, Kristin Cecilia Saue; Klufterud, Elin; Rosnes, Jan Thomas; Granum, Per Einar. Role of the gerA operon in L-alanine germination of Bacillus licheniformis spores. BMC Microbiology 2012 ;Volum 12.
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Background The genome of Bacillus licheniformis DSM 13 harbours three neighbouring open reading frames showing protein sequence similarities to the proteins encoded from the Bacillus subtilis subsp. subtilis 168 gerA operon, GerAA, GerAB and GerAC. In B. subtilis, these proteins are assumed to form a germinant receptor involved in spore germination induced by the amino acid L-alanine. Results In this study we show that disruption of the gerAA gene in B. licheniformis MW3 hamper L-alanine and casein hydrolysate-triggered spore germination, measured by absorbance at 600 nm and confirmed by phase contrast microscopy. This ability was restored by complementation with a plasmid-borne copy of the gerA locus. Addition of D-alanine in the casein hydrolysate germination assay abolished germination of both B. licheniformis MW3 and the complementation mutant. Germination of both B. licheniformis MW3 and the gerA disruption mutant was induced by the non-nutrient germinant Ca2+-Dipicolinic acid. Conclusions These results demonstrate that the B. licheniformis MW3 gerA locus is involved in germination induced by L-alanine and potentially other components present in casein hydrolysate.
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