Using A Part Of 16S RDNA Sequence And Cluster Analysis To Differentiate Lactic Acid Cocci

Lactic acid bacteria are widely distributed in the nature. The genus Lactobacillus, Lactococcus, Pediococcus and Leuconostoc are included being representatives in this group. They could be isolated from soils, waters, plants, silages, waste products, and also from the intestinal tract of animals and humans. The lactic acid fermentation, which these bacteria perform has long been known and applied by the humans for making different foodstuffs. It plays an essential role in the production of all dairy products and is involved in the production of many other foods - sausages, pickles, and drinks etc. The wild strains, in biotechnological aspect are perspective as bacteriocin producer and probiotics. They have a potential use for the establishing of new, the so-called "functional foods".The aim of this study is the identification of Lactic acid cocci by cluster analysis differentiating a part of 16S rDNA sequence. The 16S rRNA gene of 9 strains were amplified in vitro with the primers designed using Primer Premier 5 by the reported Lactic acid cocci 16S rRNA sequence. The novel methods include: genomic DNAs preparation, PCR amplification and purification of product, cloning of PCR products with pMD18-T vecter, sequencing, and cluster analysis.A 634bp fragment was amplified by the above primers. The amplified product was purified after electrophoresis. Then the purification of product was ligated into correspondingly restricted pMD18-T vector. And the recombination was transformed in Ecoli JM109. For identification the plasmid was cut with Hindâ…¢ and EcoR â…  . The cut products were 2635bp and 691bp. To identify the strain, the 16S rDNA sequence was compared with type strains of the same genus. The result can be abtained according to the homology.9 strains of Lactic acid cocci were isolated from milk and silages. All the 9 strains were identified in genus, and 6 strains were identified in species according to the criteria and description of Bergey's manual of systematic bacteriology, which incloud Lactococcus lactis (6 strains), Enterococcus (1 strains), Pediococcus (2 strains). These 3 strains, Enterococcus (1 strains) and Pediococcus (2 strains) were not determined in species based on analyzing the part of 16S rDNA sequence data. The conclusion is that this method is a good one to differentiate Lactic acid cocci.