16S rRNA gene surveys in the water column reveal a niche differentiation of certain genera within the beta-AOB with the predominance of Nitrosomonas spp. in attached surfaces (particle-associated) and of Nitrosospira spp. as free-living microorganisms (Phillips et al. 1999).
The groEL gene is highly conserved but sufficiently variable to form the basis for genetic target design allowing differentiation of the genera Orientia and Rickettsia, as sequence analysis demonstrated 99.5% identity within the current 23 Thai isolates, and 98.8% identity for all available groEL sequences, including those deposited in GenBank.
The differentiation of these two genera from their common ancestor is, to a large extent, due to size evolution.
All methods, except 16S rRNA and codon usage, provided significant (P < 0.001; T test) taxonomic resolution for differentiation of species and genera of vibrios.
The cladistic analysis further supports that the fossil represents a moment in the history of the tribe, previous to the differentiation of the two extant genera.
To our knowledge, the designed assay is the first test for detection and differentiation of species belonging to these two genera in a single PCR.
In particular, the differentiation of the species within the Nomascus genera was inferred to have occurred from 4.2 mya to as recently as 0.55 mya [4].
However, because of the large material to investigate, this is a separate study on which we are currently working because while there are previous studies focusing on the Bel/Pao and Ty1/Copia groups there is not yet a comprehensive phylogenetic differentiation of these groups into clades and genera.
In summary our results show that both FTIR spectroscopy and MALDI-TOF MS are suitable for the identification and differentiation of mastitis associated Streptococcus species and related genera.
