In this study, mitochondrial DNA analysis using 16S ribosomal DNA (rDNA) was performed to investigate the phylogeny relationship of Trichiurus lepturus in the Persian Gulf compared to the other investigated area. The amplification of 16S rDNA resulted in a product of 600 bp in all samples. The results showed that the isolated strain belongs to T. lepturus showing 42 divergence sites among the s...

The taxonomy of the "Aeromonas hydrophila" complex (comprising the species A. hydrophila, A. bestiarum, A. salmonicida, and A. popoffii) has been controversial, particularly the relationship between the two relevant fish pathogens A. salmonicida and A. bestiarum. In fact, none of the biochemical tests evaluated in the present study were able to separate these two species. One hundred and sixtee...

The phylogenetic relationships of Enterobacter sakazakii strains were investigated using 16S ribosomal DNA (rDNA) and hsp60 sequencing. Each analysis distributed E. sakazakii strains among four clusters, indicating substantial taxonomic heterogeneity. The E. sakazakii type strain 16S rDNA sequence was 97.8% similar to that of Citrobacter koseri but 97.0% similar to that of Enterobacter cloacae.

In an attempt to clarify the taxonomy of the Mycobacterium avium complex, the relationship between IS1245 RFLP, growth temperature, 16S rDNA signature sequences and the 16S-23S rDNA internally transcribed spacer (ITS) of 160 M. avium-complex isolates from different sources was investigated. All 70 isolates identified as M. avium by INNO-LiPA MYCOBACTERIA (Innogenetics, Belgium), a DNA probe tes...

Endophytic bacterial diversity was estimated in Mexican husk tomato plant roots by amplified rDNA restriction analysis and sequence homology comparison of the 16S rDNA genes. Sixteen operational taxonomic units from the 16S rDNA root library were identified based on sequence analysis, including the classes Gammaproteobacteria, Betaproteobacteria, Actinobacteria, and Bacilli. The predominant gen...

The surface layer of the oceans and other aquatic environments contains many bacteria that range in activity, from dormant cells to those with high rates of metabolism. However, little experimental evidence exists about the activity of specific bacterial taxa, especially rare ones. Here we explore the relationship between abundance and activity by documenting changes in abundance over time and ...

The Polymerase Chain Reaction (PCR) has facilitated the detection of unculturable microorganisms in virtually any environmental source and has thus been used extensively in the assessment of environmental microbial diversity. This technique relies on the assumption that the gene sequences present in the environment are complementary to the "universal" primers used in their amplification. The re...

Piscirickettsia salmonis, the etiologic agent of piscirickettsiosis, is a systemic disease of salmonid fish. Variations in virulence and mortality have been observed during epizootics at different geographical regions and in laboratory experiments with isolates from these different locations. This raises the possibility that biogeographical patterns of genetic variation might be a significant f...