In fact, the thermocycler model affected the fingerprints due to the difference in the thermal ramp. DNA preparation of each strain

and enzyme lots affected the fingerprints considerably. Especially, amplification of the 2.8-kb band appeared in strains of L. paraplantarum Selleckchem Small molecule library depended on the activity of the polymerase. Therefore, we used a single thermocycler model with a single program and the bands that appeared at least three or more times among the five experiments were considered. Cluster analysis of the band profiles divided the strains into three clusters: the main cluster, AE, consisting exclusively of the L. paraplantarum strains; cluster BE, consisting of Lactobacillus curvatus and Lactobacillus sakei; and cluster CE, consisting of phenotypically hard-to-distinguish Lactobacillus pentosus and L. plantarum (Fig. 1b). The phylogenetic tree showed a similarity

coefficient of 57.0% among the L. paraplantarum strains (Fig. 1b, cluster AE), but only 8.1% between these and BE. In order to confirm the discriminatory effectiveness of the ERIC-PCR-based techniques, we performed ERIC analysis of 141 strains of LAB including 74 identified and 67 unidentified strains in our collection. The phylogenetic tree Selleckchem Pirfenidone based on ERIC-PCR showed a cluster consisting of L. paraplantarum strains, in which five unidentified strains were included. After sequencing analysis and multiplex PCR (Torriani et al., 2001a, b), these strains were identified to the species L. paraplantarum (Table 1). This result showed that ERIC analysis is useful for the preliminary discrimination of L. paraplantarum from other Lactobacillus species. Together with nine additional strains of L. paraplantarum, we performed ERIC analysis of 43 strains of Lactobacillus (Supporting Information, Fig. S1). The phylogenetic tree based on ERIC-PCR showed three clusters: a cluster Niclosamide consisting of L. paraplantarum strains, a cluster consisting of L. plantarum strains, and a cluster consisting of strains of L. pentosus, L. curvatus, and L. sakei. In the third cluster, a subcluster consisting strains of L. pentosus was distinguished from others consisting of strains

of L. curvatus and L. sakei. Although L. paraplantarum, L. plantarum, and L. pentosus are considered to be phenotypically close (Curk et al., 1996), ERIC-PCR produced considerable DNA polymorphisms among these species; five bands of 3, 1.25, 1.05, 0.82, and 0.35 kb were typically observed in strains of the species L. plantarum, whereas the band of 0.82 kb was common to strains of the species L. pentosus. Further, three intensive bands of 1.15, 0.95, and 0.45 kb were common to most strains of the species L. curvatus. These data suggest that the ERIC-1R and ERIC-2 primers are useful for generating discriminatory polymorphisms from different species of Lactobacillus. In RAPD-PCR, none of the four primers yielded a band that was specific to L.