title: Involvement of alanine racemase in germination of Bacillus cereus spores lacking an intact exosporium.
abstract: The L-alanine mediated germination of food isolated Bacillus cereus DSA 1 spores, which lacked an intact exosporium, increased in the presence of D-cycloserine (DCS), which is an alanine racemase (Alr) inhibitor, reflecting the activity of the Alr enzyme, capable of converting L-alanine to the germination inhibitor D-alanine. Proteomic analysis of the alkaline extracts of the spore proteins, which include exosporium and coat proteins, confirmed that Alr was present in the B. cereus DSA 1 spores and matched to that encoded by B. cereus ATCC 14579, whose spore germination was strongly affected by the block of conversion of L- to D-alanine. Unlike ATCC 14579 spores, L-alanine germination of B. cereus DSA 1 spores was not affected by the preincubation with DCS, suggesting a lack of restriction in the reactant accessibility.
authors.affiliation: Department of Food Science, University of Udine, Via Sondrio 2/A, 33100, Udine, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Venir
authors.forename: Manuela
authors.initials: M
authors.lastname: Del Torre
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Cunsolo
authors.forename: Rosaria
authors.initials: R
authors.lastname: Saletti
authors.forename: Rita
authors.initials: R
authors.lastname: Musetti
authors.forename: Mara Lucia
authors.initials: ML
authors.lastname: Stecchini
mesh_terms: D000409:Alanine / Q000378:metabolism / Q000494:pharmacology; D000411:Alanine Racemase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D001409:Bacillus cereus / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D003523:Cycloserine / Q000378:metabolism / Q000494:pharmacology; D005516:Food Microbiology; D008969:Molecular Sequence Data; D040901:Proteomics; D013171:Spores, Bacterial / Q000166:cytology / Q000201:enzymology / Q000502:physiology
chemical_list: D003523:Cycloserine; D000411:Alanine Racemase; D000409:Alanine