Mycoplasma bovis 5'-nucleotidase is a virulence factor conferring mammary fitness in bovine mastitis.

Nucleases and 5' nucleotidase (5'-NT) play essential roles in cell biology and are often associated with bacterial virulence. In Mycoplasma spp., which have limited metabolic capacities and rely on nutrient availability, these enzymes are of significant importance for nucleotide salvage.

An atypical GdpP enzyme linking cyclic nucleotide metabolism to osmotic tolerance and gene regulation in .

Nucleotide second messengers play an important role in bacterial adaptation to environmental changes. Recent evidence suggests that some of these regulatory molecular pathways were conserved upon the degenerative evolution of the wall-less mycoplasmas. We have recently reported the occurrence of a phosphodiesterase (PDE) in the ruminant pathogen , which was involved in c-di-AMP metabolism.

Microbiota members from body sites of dairy cows are largely shared within individual hosts throughout lactation but sharing is limited in the herd.

Background: Host-associated microbes are major determinants of the host phenotypes. In the present study, we used dairy cows with different scores of susceptibility to mastitis with the aim to explore the relationships between microbiota composition and different factors in various body sites throughout lactation as well as the intra- and inter-animal microbial sharing.

Results: Microbiotas from the mouth, nose, vagina and milk of 45 lactating dairy cows were characterized by metataxonomics at four time points during the first lactation, from 1-week pre-partum to 7 months post-partum.

Impacts of restriction-modification systems on pan-epigenome dynamics and genome plasticity.

DNA methylations play an important role in the biology of bacteria. Often associated with restriction modification (RM) systems, they are important drivers of bacterial evolution interfering in horizontal gene transfer events by providing a defence against foreign DNA invasion or by favouring genetic transfer through production of recombinogenic DNA ends. Little is known regarding the methylome of the genus, which encompasses several pathogenic species with small genomes.

Mycoplasma agalactiae ST35: a new sequence type with a minimal accessory genome primarily affecting goats.

Background: Mycoplasma agalactiae, causing agent of contagious agalactia, infects domestic small ruminants such as sheep and goats but also wild Caprinae. M. agalactiae is highly contagious and transmitted through oral, respiratory, and mammary routes spreading rapidly in an infected herd.

Genome Mosaicism in Field Strains of Mycoplasma bovis as Footprints of In-Host Horizontal Chromosomal Transfer.

Horizontal gene transfer was long thought to be marginal in Mollicutes, but the capacity of some of these wall-less bacteria to exchange large chromosomal regions has been recently documented. Mycoplasma chromosomal transfer (MCT) is an unconventional mechanism that relies on the presence of a functional integrative conjugative element (ICE) in at least one partner and involves the horizontal acquisition of small and large chromosomal fragments from any part of the donor genome, which results in progenies composed of an infinite variety of mosaic genomes. The present study focuses on Mycoplasma bovis, an important pathogen of cattle responsible for major economic losses worldwide.

The Airway Pathobiome in Complex Respiratory Diseases: A Perspective in Domestic Animals.

Respiratory infections in domestic animals are a major issue for veterinary and livestock industry. Pathogens in the respiratory tract share their habitat with a myriad of commensal microorganisms. Increasing evidence points towards a respiratory pathobiome concept, integrating the dysbiotic bacterial communities, the host and the environment in a new understanding of respiratory disease etiology.

Bacterial Conjugation Protocol for Ruminant Mycoplasmas.

In , two simultaneous processes of DNA transfer have been described that require direct cell-to-cell contact and are similar to conjugation. One involves the self-transmission of an integrative conjugative element (ICE) while the second concerns the horizontal transfer of large and small fragments of chromosomal DNA. Here, we describe an optimized conjugation protocol for the horizontal transfer of ICE or chromosomal DNA carrying antibiotic resistance markers (, tetracycline, gentamicin, puromycin) from donor to recipient mycoplasma cells.

Genomic Islands in Mycoplasmas.

Bacteria of the genus are characterized by the lack of a cell-wall, the use of UGA as tryptophan codon instead of a universal stop, and their simplified metabolic pathways. Most of these features are due to the small-size and limited-content of their genomes (580-1840 Kbp; 482-2050 CDS). Yet, the genus encompasses over 200 species living in close contact with a wide range of animal hosts and man.

in Spanish Cattle Herds: Two Groups of Multiresistant Isolates Predominate, with One Remaining Susceptible to Fluoroquinolones.

is an important bovine pathogen causing pneumonia, mastitis, and arthritis and is responsible for major economic losses worldwide. In the absence of an efficient vaccine, control of infections mainly relies on antimicrobial treatments, but resistance is reported in an increasing number of countries. To address the situation in Spain, was searched in 436 samples collected from beef and dairy cattle (2016-2019) and 28% were positive.

An emerging role for cyclic dinucleotide phosphodiesterase and nanoRNase activities in Mycoplasma bovis: Securing survival in cell culture.

Mycoplasmas are host-restricted prokaryotes with a nearly minimal genome. To overcome their metabolic limitations, these wall-less bacteria establish intimate interactions with epithelial cells at mucosal surfaces. The alarming rate of antimicrobial resistance among pathogenic species is of particular concern in the medical and veterinary fields.

Mbov_0503 Encodes a Novel Cytoadhesin that Facilitates Interaction with Tight Junctions.

Molecules contributing to microbial cytoadhesion are important virulence factors. In , a minimal bacterium but an important cattle pathogen, binding to host cells is emerging as a complex process involving a broad range of surface-exposed structures. Here, a new cytoadhesin of was identified by producing a collection of individual knock-out mutants and evaluating their binding to embryonic bovine lung cells.

Extracellular DNA: A Nutritional Trigger of Cytotoxicity.

Microbial access to host nutrients is a key factor of the host-pathogen interplay. With their nearly minimal genome, wall-less bacteria of the class have limited metabolic capacities and largely depend on host nutrients for their survival. Despite these limitations, host-restricted mycoplasmas are widely distributed in nature and many species are pathogenic for humans and animals.

Mycoplasma Chromosomal Transfer: A Distributive, Conjugative Process Creating an Infinite Variety of Mosaic Genomes.

The capacity of Mycoplasmas to engage in horizontal gene transfers has recently been highlighted. Despite their small genome, some of these wall-less bacteria are able to exchange multiple, large portions of their chromosome via a conjugative mechanism that does not conform to canonical Hfr/ models. To understand the exact features underlying mycoplasma chromosomal transfer (MCT), extensive genomic analyses were performed at the nucleotide level, using individual mating progenies derived from our model organism, .

High Prevalence of Integrative and Conjugative Elements Encoding Transcription Activator-Like Effector Repeats in .

Integrative and conjugative elements (ICEs) are modular mobile genetic elements that can disseminate through excision, circularization, and transfer. Mycoplasma ICEs have recently been found distributed among some mycoplasma species and there is accumulating evidence that they play a pivotal role in horizontal gene transfers. The occurrence of ICEs has not been documented in , a human urogenital pathogen responsible for urogenital infections, neonatal infections and extragenital infections.

Large-Scale Analysis of the Genome Identified Non-essential, Adhesion- and Virulence-Related Genes.

is an important pathogen of cattle causing bovine mycoplasmosis. Clinical manifestations are numerous, but pneumonia, mastitis, and arthritis cases are mainly reported. Currently, no efficient vaccine is available and antibiotic treatments are not always satisfactory.

Random transposon insertion in the Mycoplasma hominis minimal genome.

Mycoplasma hominis is an opportunistic human pathogen associated with genital and neonatal infections. Until this study, the lack of a reliable transformation method for the genetic manipulation of M. hominis hindered the investigation of the pathogenicity and the peculiar arginine-based metabolism of this bacterium.

First detection of Mycoplasma wenyonii in France: Identification, evaluation of the clinical impact and development of a new specific detection assay.

Mycoplasma wenyonii, a hemoplasma infecting cattle, was never detected in France. In 2014, evocative inclusions were observed in erythrocytes from cattle presenting milk drops, anemia, and edema in Brittany (France). A survey was then initiated to investigate the epidemiological situation and correlate mycoplasma detection with clinical signs.

Mycoplasmas under experimental antimicrobial selection: The unpredicted contribution of horizontal chromosomal transfer.

Horizontal Gene Transfer was long thought to be marginal in Mycoplasma a large group of wall-less bacteria often portrayed as minimal cells because of their reduced genomes (ca. 0.5 to 2.

The Integrative Conjugative Element (ICE) of : Key Elements Involved in Horizontal Dissemination and Influence of Coresident ICEs.

The discovery of integrative conjugative elements (ICEs) in wall-less mycoplasmas and the demonstration of their role in massive gene flows within and across species have shed new light on the evolution of these minimal bacteria. Of these, the ICE of the ruminant pathogen (ICEA) represents a prototype and belongs to a new clade of the Mutator-like superfamily that has no preferential insertion site and often occurs as multiple chromosomal copies. Here, functional genomics and mating experiments were combined to address ICEA functions and define the minimal ICEA chassis conferring conjugative properties to Data further indicated a complex interaction among coresident ICEAs, since the minimal ICEA structure was influenced by the occurrence of additional ICEA copies that can -complement conjugation-deficient ICEAs.

Vpma phase variation is important for survival and persistence of Mycoplasma agalactiae in the immunocompetent host.

Despite very small genomes, mycoplasmas retain large multigene families encoding variable antigens whose exact role in pathogenesis needs to be proven. To understand their in vivo significance, we used Mycoplasma agalactiae as a model exhibiting high-frequency variations of a family of immunodominant Vpma lipoproteins via Xer1-mediated site-specific recombinations. Phase-Locked Mutants (PLMs) expressing single stable Vpma products served as first breakthrough tools in mycoplasmology to study the role of such sophisticated antigenic variation systems.

The Gene and Putative Peptidase Genes May Be Required for Virulence in Mycoplasma gallisepticum.

Relatively few virulence genes have been identified in pathogenic mycoplasmas, so we used signature-tagged mutagenesis to identify mutants of the avian pathogen with a reduced capacity to persist and compared the levels of virulence of selected mutants in experimentally infected chickens. Four mutants had insertions in one of the two incomplete operons, and a further three had insertions in distinct hypothetical genes, two containing peptidase motifs and one containing a member of a gene family. The three hypothetical gene mutants and the two with insertions in were used to infect chickens, and all five were shown to have a reduced capacity to induce respiratory tract lesions.

Integrative conjugative elements are widespread in field isolates of Mycoplasma species pathogenic for ruminants.

Comparative genomics have revealed massive horizontal gene transfer (HGT) between Mycoplasma species sharing common ruminant hosts. Further results pointed toward an integrative conjugative element (ICE) as an important contributor of HGT in the small-ruminant-pathogen Mycoplasma agalactiae. To estimate the prevalence of ICEs in ruminant mycoplasmas, we surveyed their occurrence in a collection of 166 field strains representing 4 (sub)species that are recognized as major pathogens.

Random insertion and gene disruption via transposon mutagenesis of Ureaplasma parvum using a mini-transposon plasmid.

While transposon mutagenesis has been successfully used for Mycoplasma spp. to disrupt and determine non-essential genes, previous attempts with Ureaplasma spp. have been unsuccessful.

Chromosomal transfers in mycoplasmas: when minimal genomes go mobile.

Unlabelled: Horizontal gene transfer (HGT) is a main driving force of bacterial evolution and innovation. This phenomenon was long thought to be marginal in mycoplasmas, a large group of self-replicating bacteria characterized by minute genomes as a result of successive gene losses during evolution. Recent comparative genomic analyses challenged this paradigm, but the occurrence of chromosomal exchanges had never been formally addressed in mycoplasmas.