To understand the pattern of nucleotide sequence variation among bacteria that frequently exchange chromosomal genes, we analyzed sequences of the recA, argF, and rho genes, as well as part of the small-subunit (16S) rRNA gene, from about 50 isolates of human commensal Neisseria species and the pathogenic N. meningitidis and N. gonorrhoeae. Almost all isolates of these species could be assigned...

The identification and phylogenetic relationships of bacteria within the Bacillus cereus group are controversial. This study aimed at determining the taxonomic affiliations of these strains using the whole-genome sequence-based Genome BLAST Distance Phylogeny (GBDP) approach. The GBDP analysis clearly separated 224 strains into 30 clusters, representing eleven known, partially merged species an...

<p>The present study was performed to assess the genetic variations among six rabbit breeds in Egypt based on mitochondrial 16S rRNA sequences. The length of partial ranged from 546 bp 558 bp. sequenced regions were submitted GenBank/NCBI under accession numbers (MW052052 - MW052057). average content A+T 57% all breeds. Among breeds, percentages distance values 0.000 0.004. highest P-dist...

Phylogenetic relationship of 22 FLPs was revealed on the basis of polymorphism in three genes namely 16S rDNA, Pseudomonas-specific and rpoD gene regions. The primers for 16S rDNA, Pseudomonas-specific region and rpoD gene region were amplifying a region of 1492, 990 and 760 bp, respectively, from all the isolates investigated. The RFLP analysis of the PCR products resulted in a classification ...

Nucleotide sequences of approximately 213 bp of the nif H-D intergene and the beginning of nifD were determined for symbiotic Frankia isolates from the major host-infectivity groups. This region of the nif operon is variable enough to classify most infective Frankia strains at the species level. Phylogenetic inferences from these sequences are in agreement with the 16S rRNA-derived phylogeny of...

Nucleotide sequences of approximately 2 13 bp of the nifH-D intergene and the beginning of n ifD were determined for symbiotic Frunkiu isolates from the major host-infectivity groups. This region of the n ifoperon is variable enough to classify most infective Frunkia strains at the species level. Phylogenetic inferences from these sequences are in agreement with the 16s rRNA-derived phylogeny o...

Horizontal gene transfer (HGT) of operational genes has been widely reported in prokaryotic organisms. However, informational genes such as those involved in transcription and translation processes are very difficult to be horizontally transferred, as described by Woese's complexity hypothesis. Here, we analyzed all of the completed prokaryotic genome sequences (2,143 genomes) in the NCBI (Nati...

Eleven strains of a hitherto unknown, Gram-negative, anaerobic coccus were recovered from various human clinical samples of patients hospitalized in two geographically distant French hospitals. These strains displayed the morphology and growth characteristics of those related to the genus Acidaminococcus. The clinical isolates shared at least 99.9 and 99.7 % of their nucleotide positions in the...

The class Thermoplasmata harbors huge uncultured archaeal lineages at the order level, so-called Groups E2 and E3. A novel archaeon Kjm51a affiliated with Group E2 was enriched from anaerobic sludge in the present study. Clone library analysis of the archaeal 16S rRNA and mcrA genes confirmed a unique archaeal population in the enrichment culture. The 16S rRNA gene-based phylogeny revealed that...

The current picture of bacterial evolution is based largely on studies of 16S rRNA. However, this is just one gene. It is known that horizontal gene transfer can occur between bacterial species, although the frequency and implications of this are not fully understood. If horizontal transfer were frequent, there would be no single evolutionary tree for bacteria because each gene would follow a d...