Mycoplasma haemocanis – the canine hemoplasma and its feline counterpart in the genomic era

Abstract

Mycoplasma haemocanis is a hemotrophic mycoplasma (hemoplasma), blood pathogen that may cause acute disease in immunosuppressed or splenectomized dogs. The genome of the strain Illinois, isolated from blood of a naturally infected dog, has been entirely sequenced and annotated to gain a better understanding of the biology of M. haemocanis. Its single circular chromosome has 919 992 bp and a low G + C content (35%), representing a typical mycoplasmal genome. A gene-by-gene comparison against its feline counterpart, M. haemofelis, reveals a very similar composition and architecture with most of the genes having conserved synteny extending over their entire chromosomes and differing only by a small set of unique protein coding sequences. As in M. haemofelis, M. haemocanis metabolic pathways are reduced and apparently rely heavily on the nutrients afforded by its host environment. The presence of a major percentage of its genome dedicated to paralogous genes (63.7%) suggests that this bacterium might use antigenic variation as a mechanism to evade the host’s immune system as also observed in M. haemofelis genome. Phylogenomic comparisons based on average nucleotide identity (ANI) and tetranucleotide signature suggest that these two pathogens are different species of mycoplasmas, with M. haemocanis infecting dogs and M. haemofelis infecting cats.

Analysis of risk factors and prevalence of haemoplasma infection in dogs

“…A similar result, in which Mhc and Mhf 16S rRNA gene sequences shared >99% identity, has been previously reported (Brinson and Messick, 2001). However, phylogenetic studies based on the RNase P RNA gene showed that Mhc is a distinct species infecting the dog (do Nascimento et al, 2012). Unfortunately further phylogenetic analysis was not possible in the current study as insufficient haemoplasma DNA was available from these dogs for further amplification studies.…”

Microscopy and genomic analysis of Mycoplasma parvum strain Indiana

“…M. parvum has the smallest single, circular chromosome of all the Mycoplasma genomes sequenced to date. The characteristics of the M. parvum genome, including its small size, low G + C content, use of UGA codon to encode tryptophan, and number of tRNA and rRNA were in agreement with those reported for the genomes of other hemoplasmas and are typical of mycoplasmas [ 1 , 4 , 6 ]. In addition, the percentage of CDS dedicated to paralogous genes (24.3%) was similar to that reported for other hemoplasmas [ 1 – 8 , 10 ].…”

When present, repeats are abundant in respiratory system pathogens besides virulence associated coding DNA sequences of Mycoplasmas

“…Earlier studies have reported trinucleotide motif GAA(n) in pMGA of M. gallisepticum 17,50,51 The most abundant repeat motif is AAT followed by TAA but CG rich trinucleotide repeats are present in few Mycoplasmas (data not shown). Earlier study reports GAT repeats in rpoD gene, ATT repeat in pgsA gene, GAA in oppA gene of M. hominis 53 54 . The present study shows TTC repeats in two hypothetical protein CDS (data not shown) and one in Transport (permease) CDS (data not shown).…”