title: The presence of two S-layer-protein-encoding genes is conserved among species related to Lactobacillus acidophilus.
abstract: Previously we have shown that the type strain of Lactobacillus acidophilus possesses two S-protein-encoding genes, one of which is silent, on a chromosomal segment of 6 kb. The S-protein-encoding gene in the expression site can be exchanged for the silent S-protein-encoding gene by inversion of this slp segment. In this study the presence of S-protein and corresponding S-protein-encoding genes of strains belonging to species that are closely related to L. acidophilus was determined. All strains investigated were identified by numerical comparison of highly standardized one-dimensional SDS-PAGE whole-cellular-protein patterns. Western blot and Southern blot methods were used to identify the presence of, and homology between, S-proteins and S-protein-encoding genes. From these analyses we conclude that strains of L. acidophilus, L. crispatus, L. amylovorus and L. gallinarum possess an S-layer and contain two slp genes. Strains of L. helveticus possess an S-layer but have only one intact slp gene. Strains of L. gasseri, L. johnsonii and L. delbrueckii subsp. bulgaricus have neither an S-layer nor S-protein-encoding genes hybridizing with probes derived from the L. acidophilus slpA or slpB region. The presence of a highly conserved 5' region in the slp genes of strains of L. acidophilus, L. crispatus, L. amylovorus and L. gallinarum suggests that S-layer variation is a common feature for strains of these species.
authors.affiliation: BioCentrum Amsterdam, University of Amsterdam, The Netherlands. H.J.Boot@ID.DLO.NL
authors.forename: H J
authors.initials: HJ
authors.lastname: Boot
authors.forename: C P
authors.initials: CP
authors.lastname: Kolen
authors.forename: B
authors.initials: B
authors.lastname: Pot
authors.forename: K
authors.initials: K
authors.lastname: Kersters
authors.forename: P H
authors.initials: PH
authors.lastname: Pouwels
mesh_terms: D001426:Bacterial Proteins / Q000032:analysis; D015139:Blotting, Southern; D015153:Blotting, Western; D002874:Chromosome Mapping; D004591:Electrophoresis, Polyacrylamide Gel; D007779:Lactobacillus acidophilus / Q000235:genetics*; D008565:Membrane Proteins / Q000032:analysis / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid
chemical_list: D001426:Bacterial Proteins; D008565:Membrane Proteins