140 C.M. Lee et al. Fig. 5. Southern blot analysis of the 16S rRNA gene of Lactobacillus reuteri C 1 (a), C 16 (b) and C 10 (c). Several enzymes were used to digest genomic DNA of the Lactobacillus strains. Lane 1, BamHI; lane 2, BclI; lane 3, EcoRI; lane 4, EcoRV; lane 5, HindIII; lane 6, NheI; lane 7, SalI. gene multiplicity is potentially useful in physiological and evolutionary study of bacteria. In addition, copy numbers of the 16S rRNA gene are important as a correction factor to normalize the data collected on the estimation of a bacterial community, especially when technology such as quantitative real-time PCR is employed. Acknowledgements We would like to acknowledge the Ministry of Science, Technology and Innovation of Malaysia for providing the ﬁnancial support under the ScienceFund (02-01-04-SF0052) for this study. We also thank Stella Gen Sdn. Bhd. for providing the 12 Lactobacillus strains used in this study. Statement Reuse of this article is permitted in accordance with the Creative Commons Deed, Attribution 2.5, which does not permit commercial exploitation. References Acinas SG, Marcelino LA, Klepac-Ceraj V & Polz MF (2004) Divergence and redundancy of 16S rRNA sequences in genomes with multiple rrn operons. J Bacteriol 186: 2629–2635. Altermann E, Russell WM, Azcarate-Peril MA et al. (2005) Complete genome sequence of the probiotic lactic acid bacterium Lactobacillus acidophilus NCFM. Proc Natl Acad Sci USA 102: 3906–3912. c 2008 The Authors Journal compilation c 2008 Federation of European Microbiological Societies Published by Blackwell Publishing Ltd. Bjo¨rkroth KJ & Korkeala HJ (1996) rRNA gene restriction patterns as a characterization tool for Lactobacillus sake strains producing ropy slime. Int J Food Microbiol 30: 293–302. Bjo¨rkroth KJ & Korkeala HJ (1997) Use of rRNA gene restriction patterns to evaluate lactic acid bacterium contamination of vacuum-packaged sliced cooked whole-meat product in a meat processing plant. Appl Environ Microbiol 63: 448–453. Brosius J, Palmer JL, Kennedy JP & Noller HF (1978) Complete nucleotide sequence of a 16S ribosomal RNA gene from Escherichia coli. Proc Natl Acad Sci USA 75: 4801–4805. Chevallier B, Hubert J-C & Kammerer B (1994) Determination of chromosome size and number of rrn loci in Lactobacillus plantarum by pulse-ﬁeld gel electrophoresis. FEMS Microbiol Lett 120: 51–56. Claesson MJ, Li Y, Leahy S et al. (2006) Multireplicon genome architecture of Lactobacillus salivarius. Proc Natl Acad Sci USA 103: 6718–6723. Dudez A-M, Chaillou S, Hissler L, Stentz R, Champomier-Verge`s M-C, Alpert C-A & Zagorec M (2002) Physical and genetic map of the Lactobacillus sakei 23 K chromosome. Microbiology 148: 421–431. Gonz a´lez-Escalona N, Romero J & Espejo RT (2005) Polymorphism and gene conversion of the 16S rRNA genes in the multiple rRNA operons of Vibrio parahaemolyticus. FEMS Microbiol Lett 246: 213–219. Jin LZ, Ho YW, Ali MA, Abdullah N, Ong KB & Jalaludin S (1996) Adhesion of Lactobacillus isolates to intestinal epithelial cells of chicken. Lett Appl Microbiol 22: 229–232. Jin LZ, Ho YW, Abdullah N & Jalaludin S (1998) Growth performance, intestinal microbial populations, and serum cholesterol of broilers fed diets containing Lactobacillus cultures. Poult Sci 77: 1259–1265. FEMS Microbiol Lett 287 (2008) 136–141