Indeed, the sequence of the selleck screening library plasmid that we isolated from a M. leachii strain was found to be identical to that of the previously described pBG7AU. This result is not surprising since the 2 M. leachii strains, though distinct, were recovered from the same outbreak in Australia [21]. Similarly, the 2 field strains of M. yeatsii were shown to harbor plasmids that are 97% identical. In this case, however, the strains sharing the same geographical origin were isolated 8 years apart. In contrast, the 2 plasmids isolated from the M. cottewii species were shown to have different sizes (1,565

vs 1,041 bp) and nucleotide sequences (42% identity only). The pMyBK1 plasmid, sequenced by others (Genbank accession # EU429323; [25]) and also found in the M. yeatsii type strain, is certainly a particular case because of its larger size (3,422 bp) and low nucleotide identity (20-37%)

learn more in comparison to other mycoplasma plasmids. Proposed nomenclature for mycoplasma plasmids With the description of this fairly large set of plasmids, a proposal for a new nomenclature of mycoplasma plasmids seemed justified. First, we considered that there was no need to give a different name to a plasmid that was found identical to a previously described replicon (e.g. pBG7AU). For the plasmids that are very close to each other (nucleotide identity & 95%), we considered that they were variants and should be given IWR-1 in vitro the same name followed by the suffix “-n” where n indicated the number by chronological HSP90 order in this series of plasmids (Table 1); the plasmid with the suffix “-1” being the prototype of the plasmid series (e.g.

pMG1A-1). This same rule was used for variants of plasmids described by others (e.g. pMmc-95010-2). Finally, the plasmids were separated into two groups (G1 and G2) according to their rep sequences (see below). According to this nomenclature, we identified 9 new plasmids (pMG1A-1, pMG1B-1, pMG1C-1, pMG2A-1, pMG2B-1, pMG2C-1, pMG2D-1, pMG2E-1 and pMG2F-1) and 11 variants of these plasmids or of plasmids previously reported. Sequences of these 9 new plasmids have been deposited in GenBank (Table 1). Mycoplasma plasmids share a common genetic organization With the exception of pMyBK1for which a specific analysis is provided further, all plasmids shared the same overall genetic organization, similar to those of pMmc-95010 [23] and pMV158, a small, broad-host-range plasmid, originally isolated from Streptococcus agalactiae that is considered the prototype of the rolling circle replicating plasmid family [45] (Figure 3A). It consists of two CDSs transcribed in the same direction, followed by an inverted repeat sequence ended by a stretch of thymidine residues that is typical of rho-independent transcription terminators (Tcr; Figure 3A). Figure 3 Molecular features of mycoplasma plasmids of the pMV158 family. A. Typical genetic organisation of the replication region of plasmids belonging to the pMV158 family.