CHARACTERIZATION OF BIFIDOBACTERIA BY RANDOM DNA AMPLIFICATION

RAPD conditions were optimized to generate reproducible banding patter ns by testing primers, thermocyclers and overall reproducibility in re peat DNA analysis and separate DNA extractions. Five primers were chos en on the basis of band intensity and distribution (between 2 and 10 b ands) which clearly distinguished among strains of Bifidobacterium ado lescentis, B. animalis, B. bifidum, B. breve, B. infantis and B. longu m. The use of five single-primer reactions under optimized conditions improved the resolution and accuracy of the RAPD method for the charac terization of dairy-related bifidobacteria. The results indicated that this method was highly reproducible in repeated analysis. Similarity between bifidobacteria strains was evaluated based on their RAPD profi les. Using a set of five primers, it was demonstrated that it may be p ossible to distinguish three different species of Bifidobacterium (B. breve, B. bifidum and B. adolescentis), based on similarity of the RAP D profiles to known reference strains. Furthermore, application of the RAPD technique may also be useful and faster, than traditional system atics for placement of industrial strains into specific clusters (eith er B. longum/infantis or B. animalis/lactis). (C) 1998 Elsevier Scienc e B.V. All rights reserved.