Construction of a combined physical and genetic map of the chromosome of Lactobacillus acidophilus ATCC 4356 and characterization of the rRNA operons

• Published in: Microbiology (Society for General Microbiology) 2005-03, Vol.151 (3), p.875-892
• Main Authors: EL-Osta, Youssef G. Abs, Hillier, Alan J, Dobos, Marian
• Format: Article
• Language: English
• Subjects: Bacteriology; Biological and medical sciences; Chromosome Mapping; Chromosomes, Bacterial; Electrophoresis, Gel, Pulsed-Field; Fundamental and applied biological sciences. Psychology; Genetics; Lactobacillus acidophilus; Lactobacillus acidophilus - genetics; Microbiology; Molecular Sequence Data; Nucleic Acid Hybridization; Physical Chromosome Mapping; Restriction Mapping; RNA, Ribosomal, 23S - genetics; rRNA Operon - genetics; Sequence Analysis, DNA
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/mic.0.27134-0

1 School of Medical Sciences, RMIT University, Melbourne, Victoria, Australia 2 School of Agriculture and Food Systems, The University of Melbourne, Werribee, Victoria, Australia 3 Food Science Australia, Werribee, Victoria 3030, Australia Correspondence Youssef G. Abs EL-Osta y.osta{at}unimelb.edu.au The combination of PFGE and hybridization approaches was used to study the genome of Lactobacillus acidophilus neotype strain ATCC 4356. PFGE analysis of chromosomal DNA after digestion with each of the rare-cutting restriction enzymes I- Ceu I, Not I, Csp I, Sma I, Apa I and Sgr AI allowed the size of the circular chromosome of L. acidophilus to be estimated at 2·061 Mbp. The physical map contained 86 restriction sites for the six enzymes employed, with intervals between the sites varying from 1 to 88 kbp ( 0·05–4·3 % of the chromosome). Based on the physical map, a genetic map was constructed via Southern blot analyses of L. acidophilus DNA using specific gene probes. A total of 73 probes representing key genes, including 12 rRNA ( rrn ) genes, were positioned on the latter map. Mapping analysis also indicated the presence of four rrn operons ( rrnA – D ) on the chromosome, each containing a single copy of each of the three rrn genes 16S ( rrl ), 23S ( rrs ) and 5S ( rrf ). Operon rrnD was inverted in orientation with respect to the others and contained a long 16S–23S intergenic spacer region with tRNA Ile and tRNA Ala genes, whereas the other operons contained a short spacer lacking any tRNA genes. The high-resolution physical/genetic map constructed in this study provides a platform for genomic and genetic studies of Lactobacillus species and for improving industrial and probiotic strains. The GenBank/EMBL/DDBJ accession number for the 23S rRNA ( rrl ) gene reported in this paper is AJ620360 . Present address: Department of Veterinary Science, The University of Melbourne, 250 Princes Highway, Werribee, Victoria 3030, Australia. HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS INT J SYST EVOL MICROBIOL MICROBIOLOGY J GEN VIROL J MED MICROBIOL ALL SGM JOURNALS Copyright © 2005 Society for General Microbiology.