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The presence of two S-layer-protein-encoding genes is conserved among species related to Lactobacillus acidophilus

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Author: Boot, H.J. · Kolen, C.P.A.M. · Pot, B. · Kersters, K. · Pouwels, P.H.
Institution: Prins Maurits Laboratorium TNO
Source:Microbiology, 9, 142, 2375-2384
Identifier: 233434
Keywords: Biology · S-layer variation · S-protein · SDS-PAGE identification · Surface layer · Bacterial protein · Bacterial gene · Chromosome inversion · Genetic conservation · Immunoblotting · Nonhuman · Polyacrylamide gel electrophoresis · Priority journal · Silent gene · Southern blotting · Bacterial Proteins · Blotting, Southern · Blotting, Western · Chromosome Mapping · Electrophoresis, Polyacrylamide Gel · Membrane Proteins · Sequence Homology, Amino Acid · Sequence Homology, Nucleic Acid · Bacteria (microorganisms) · Lactobacillus · Lactobacillus acidophilus · Lactobacillus amylovorus · Lactobacillus crispatus · Lactobacillus delbrueckii subsp. bulgaricus · Lactobacillus gallinarum · Lactobacillus gasseri · Lactobacillus helveticus · Lactobacillus johnsonii


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.