Mycoplasma mycoides

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Francois Thiaucourt - One of the best experts on this subject based on the ideXlab platform.

  • proteomic characterization of pleural effusion a specific host niche of Mycoplasma mycoides subsp mycoides from cattle with contagious bovine pleuropneumonia cbpp
    Journal of Proteomics, 2016
    Co-Authors: Yenehiwot B. Weldearegay, Elise Schieck, Hezron Wesonga, Anne Liljander, Francois Thiaucourt, Nimmo Gicheru, Andreas Pich, Leonard M Kiirika, Peter Valentinweigand
    Abstract:

    Abstract Mycoplasma mycoides subsp. mycoides (Mmm) is the causative agent of contagious bovine pleuropneumonia (CBPP), a severe pleuropneumonia in cattle. The abnormal accumulation of pleural fluid, called pleural effusion (PE), is one of the characteristics of this disease. We performed a proteomic analysis of seven PE samples from experimentally infected cattle and characterized their composition with respect to bovine and Mmm proteins. We detected a total of 963 different bovine proteins. Further analysis indicated a strong enrichment of proteins involved in antigen processing, platelet activation and degranulation and apoptosis and an increased abundance of acute phase proteins. With regard to the pathogen, up to 108 viable Mycoplasma cells per ml were detected in the PE supernatant. The proteomic analysis revealed 350 Mycoplasma proteins, including proteins involved in virulence-associated processes like hydrogen peroxide (H2O2) production and capsule synthesis. The bovine proteins detected will aid to characterize the inflammasome during an acute pleuropneumonia in cattle and the identified Mycoplasma proteins will serve as baseline data to be compared with in vitro studies to improve our understanding of pathogenicity mechanisms. Based on our results, we named the pleural effusion an “in vivo niche” of Mmm during the acute phase of CBPP. Biological significance This is the first study on bovine pleural effusions derived from an infectious disease and the first approach to characterize the proteome of Mycoplasma mycoides in vivo. This study revealed a high number of viable Mmm cells in the pleural effusion. The bovine pleural effusion proteome during Mmm infection is qualitatively similar to plasma, but differs with respect to high abundance of acute phase proteins. On the other hand, Mmm in its natural host produces proteins involved in capsule synthesis, H2O2 production and induction of inflammatory response, supporting previous knowledge on mechanisms underlying the survival and virulence of this pathogen while inside the natural host. This knowledge forms a profound basis for testing the identified protein candidates for diagnostics or vaccines.

  • free exopolysaccharide from Mycoplasma mycoides subsp mycoides possesses anti inflammatory properties
    Veterinary Research, 2015
    Co-Authors: Philippe Totte, Clothilde Bertin, Lucia Mansosilvan, Carinne Puech, Valerie Rodrigues, Francois Thiaucourt
    Abstract:

    In this study we explored the immunomodulatory properties of highly purified free galactan, the soluble exopolysaccharide secreted by Mycoplasma mycoides subsp. mycoides (Mmm). Galactan was shown to bind to TLR2 but not TLR4 using HEK293 reporter cells and to induce the production of the anti-inflammatory cytokine IL-10 in bovine macrophages, whereas low IL-12p40 and no TNF-α, both pro-inflammatory cytokines, were induced in these cells. In addition, pre-treatment of macrophages with galactan substantially reduced lipopolysaccharide (LPS)-induced production of pro-inflammatory cytokines TNF- and IL-12p40 while increasing LPS-induced secretion of immunosuppressive IL-10. Also, galactan did not activate naive lymphocytes and induced only low production of the Th1 cytokine IFN-γ in Mmm-experienced lymphocytes. Finally, galactan triggered weak recall proliferation of CD4+ T lymphocytes from contagious bovine pleuropneumonia-infected animals despite having a positive effect on the expression of co-stimulatory molecules on macrophages. All together, these results suggest that galactan possesses anti-inflammatory properties and potentially provides Mmm with a mechanism to evade host innate and adaptive cell-mediated immune responses.

  • highly dynamic genomic loci drive the synthesis of two types of capsular or secreted polysaccharides within the Mycoplasma mycoides cluster
    Applied and Environmental Microbiology, 2015
    Co-Authors: Clothilde Bertin, Corinne Pauroblot, Josiane Courtois, Florence Tardy, F Poumarat, Pascal Sirandpugnet, Patrice Gaurivaud, Lucia Mansosilvan, Christine Citti, Francois Thiaucourt
    Abstract:

    Mycoplasmas of the Mycoplasma mycoides cluster are all ruminant pathogens. Mycoplasma mycoides subsp. mycoides is responsible for contagious bovine pleuropneumonia and is known to produce capsular polysaccharide (CPS) and exopolysaccharide (EPS). Previous studies have strongly suggested a role for Mycoplasma mycoides subsp. mycoides polysaccharides in pathogenicity. Mycoplasma mycoides subsp. mycoides-secreted EPS was recently characterized as a β(1→6)-galactofuranose homopolymer (galactan) identical to the capsular product. Here, we extended the characterization of secreted polysaccharides to all other members of the M. mycoides cluster: M. capricolum subsp. capripneumoniae, M. capricolum subsp. capricolum, M. leachii, and M. mycoides subsp. capri (including the LC and Capri serovars). Extracted EPS was characterized by nuclear magnetic resonance, resulting in the identification of a homopolymer of β(1→2)-glucopyranose (glucan) in M. capricolum subsp. capripneumoniae and M. leachii. Monoclonal antibodies specific for this glucan and for the Mycoplasma mycoides subsp. mycoides-secreted galactan were used to detect the two polysaccharides. While M. mycoides subsp. capri strains of serovar LC produced only capsular galactan, no polysaccharide could be detected in strains of serovar Capri. All strains of M. capricolum subsp. capripneumoniae and M. leachii produced glucan CPS and EPS, whereas glucan production and localization varied among M. capricolum subsp. capricolum strains. Genes associated with polysaccharide synthesis and forming a biosynthetic pathway were predicted in all cluster members. These genes were organized in clusters within two loci representing genetic variability hot spots. Phylogenetic analysis showed that some of these genes, notably galE and glf, were acquired via horizontal gene transfer. These findings call for a reassessment of the specificity of the serological tests based on Mycoplasma polysaccharides.

  • characterization of free exopolysaccharides secreted by Mycoplasma mycoides subsp mycoides
    PLOS ONE, 2013
    Co-Authors: Clothilde Bertin, Corinne Pauroblot, Josiane Courtois, Florence Tardy, F Poumarat, Lucia Mansosilvan, Francois Thiaucourt, Dominique Le Grand, Patrice Gaurivaud
    Abstract:

    Contagious bovine pleuropneumonia is a severe respiratory disease of cattle that is caused by a bacterium of the Mycoplasma genus, namely Mycoplasma mycoides subsp. mycoides (Mmm). In the absence of classical virulence determinants, the pathogenicity of Mmm is thought to rely on intrinsic metabolic functions and specific components of the outer cell surface. One of these latter, the capsular polysaccharide galactan has been notably demonstrated to play a role in Mmm persistence and dissemination. The free exopolysaccharides (EPS), also produced by Mmm and shown to circulate in the blood stream of infected cattle, have received little attention so far. Indeed, their characterization has been hindered by the presence of polysaccharide contaminants in the complex Mycoplasma culture medium. In this study, we developed a method to produce large quantities of EPS by transfer of Mycoplasma cells from their complex broth to a chemically defined medium and subsequent purification. NMR analyses revealed that the purified, free EPS had an identical b(12.6)galactofuranosyl structure to that of capsular galactan. We then analyzed intraclonal Mmm variants that produce opaque/ translucent colonies on agar. First, we demonstrated that colony opacity was related to the production of a capsule, as observed by electron microscopy. We then compared the EPS extracts and showed that the non-capsulated, translucent colony variants produced higher amounts of free EPS than the capsulated, opaque colony variants. This phenotypic variation was associated with an antigenic variation of a specific glucose phosphotransferase permease. Finally, we conducted in silico analyses of candidate polysaccharide biosynthetic pathways in order to decipher the potential link between glucose phosphotransferase permease activity and attachment/release of galactan. The co-existence of variants producing alternative forms of galactan (capsular versus free extracellular galactan) and associated with an antigenic switch constitutes a finely tuned mechanism that may be involved in virulence.

  • Mycoplasma mycoides from mycoides small colony to capri a microevolutionary perspective
    BMC Genomics, 2011
    Co-Authors: Francois Thiaucourt, Woubit Salah, Benoit Vacherie, Anne Marie Lomenech, Valerie Barbe, Virginie Dupuy, Marc Breton, Lucia Mansosilvan, Daniel Jacob, Alain Blanchard
    Abstract:

    Background The Mycoplasma mycoides cluster consists of five species or subspecies that are ruminant pathogens. One subspecies, Mycoplasma mycoides subspecies mycoides Small Colony (MmmSC), is the causative agent of contagious bovine pleuropneumonia. Its very close relative, Mycoplasma mycoides subsp. capri (Mmc), is a more ubiquitous pathogen in small ruminants causing mastitis, arthritis, keratitis, pneumonia and septicaemia and is also found as saprophyte in the ear canal. To understand the genetics underlying these phenotypic differences, we compared the MmmSC PG1 type strain genome, which was already available, with the genome of an Mmc field strain (95010) that was sequenced in this study. We also compared the 95010 genome with the recently published genome of another Mmc strain (GM12) to evaluate Mmc strain diversity.

F Poumarat - One of the best experts on this subject based on the ideXlab platform.

  • highly dynamic genomic loci drive the synthesis of two types of capsular or secreted polysaccharides within the Mycoplasma mycoides cluster
    Applied and Environmental Microbiology, 2015
    Co-Authors: Clothilde Bertin, Corinne Pauroblot, Josiane Courtois, Florence Tardy, F Poumarat, Pascal Sirandpugnet, Patrice Gaurivaud, Lucia Mansosilvan, Christine Citti, Francois Thiaucourt
    Abstract:

    Mycoplasmas of the Mycoplasma mycoides cluster are all ruminant pathogens. Mycoplasma mycoides subsp. mycoides is responsible for contagious bovine pleuropneumonia and is known to produce capsular polysaccharide (CPS) and exopolysaccharide (EPS). Previous studies have strongly suggested a role for Mycoplasma mycoides subsp. mycoides polysaccharides in pathogenicity. Mycoplasma mycoides subsp. mycoides-secreted EPS was recently characterized as a β(1→6)-galactofuranose homopolymer (galactan) identical to the capsular product. Here, we extended the characterization of secreted polysaccharides to all other members of the M. mycoides cluster: M. capricolum subsp. capripneumoniae, M. capricolum subsp. capricolum, M. leachii, and M. mycoides subsp. capri (including the LC and Capri serovars). Extracted EPS was characterized by nuclear magnetic resonance, resulting in the identification of a homopolymer of β(1→2)-glucopyranose (glucan) in M. capricolum subsp. capripneumoniae and M. leachii. Monoclonal antibodies specific for this glucan and for the Mycoplasma mycoides subsp. mycoides-secreted galactan were used to detect the two polysaccharides. While M. mycoides subsp. capri strains of serovar LC produced only capsular galactan, no polysaccharide could be detected in strains of serovar Capri. All strains of M. capricolum subsp. capripneumoniae and M. leachii produced glucan CPS and EPS, whereas glucan production and localization varied among M. capricolum subsp. capricolum strains. Genes associated with polysaccharide synthesis and forming a biosynthetic pathway were predicted in all cluster members. These genes were organized in clusters within two loci representing genetic variability hot spots. Phylogenetic analysis showed that some of these genes, notably galE and glf, were acquired via horizontal gene transfer. These findings call for a reassessment of the specificity of the serological tests based on Mycoplasma polysaccharides.

  • characterization of free exopolysaccharides secreted by Mycoplasma mycoides subsp mycoides
    PLOS ONE, 2013
    Co-Authors: Clothilde Bertin, Corinne Pauroblot, Josiane Courtois, Florence Tardy, F Poumarat, Lucia Mansosilvan, Francois Thiaucourt, Dominique Le Grand, Patrice Gaurivaud
    Abstract:

    Contagious bovine pleuropneumonia is a severe respiratory disease of cattle that is caused by a bacterium of the Mycoplasma genus, namely Mycoplasma mycoides subsp. mycoides (Mmm). In the absence of classical virulence determinants, the pathogenicity of Mmm is thought to rely on intrinsic metabolic functions and specific components of the outer cell surface. One of these latter, the capsular polysaccharide galactan has been notably demonstrated to play a role in Mmm persistence and dissemination. The free exopolysaccharides (EPS), also produced by Mmm and shown to circulate in the blood stream of infected cattle, have received little attention so far. Indeed, their characterization has been hindered by the presence of polysaccharide contaminants in the complex Mycoplasma culture medium. In this study, we developed a method to produce large quantities of EPS by transfer of Mycoplasma cells from their complex broth to a chemically defined medium and subsequent purification. NMR analyses revealed that the purified, free EPS had an identical b(12.6)galactofuranosyl structure to that of capsular galactan. We then analyzed intraclonal Mmm variants that produce opaque/ translucent colonies on agar. First, we demonstrated that colony opacity was related to the production of a capsule, as observed by electron microscopy. We then compared the EPS extracts and showed that the non-capsulated, translucent colony variants produced higher amounts of free EPS than the capsulated, opaque colony variants. This phenotypic variation was associated with an antigenic variation of a specific glucose phosphotransferase permease. Finally, we conducted in silico analyses of candidate polysaccharide biosynthetic pathways in order to decipher the potential link between glucose phosphotransferase permease activity and attachment/release of galactan. The co-existence of variants producing alternative forms of galactan (capsular versus free extracellular galactan) and associated with an antigenic switch constitutes a finely tuned mechanism that may be involved in virulence.

  • variability of a glucose phosphotransferase system permease in Mycoplasma mycoides subsp mycoides small colony
    Microbiology, 2004
    Co-Authors: Patrice Gaurivaud, Michel Solsona, Joakim Westberg, Anja Persson, Dominique Le Grand, Karlerik Johansson, F Poumarat
    Abstract:

    Intraclonal antigenic variation in pathogenic Mycoplasma species is considered an important feature of host-pathogen interaction. Such intraclonal protein variation was observed for the interaction of Mycoplasma mycoides subsp. mycoides Small Colony, the agent of contagious bovine pleuropneumonia, with mAb 3F3. Colony immunostaining allows the definition of 3F3 ON- and 3F3 OFF-type variants, which revert at low frequency. Targets of mAb 3F3 were shown to be surface located, and resided on multiple polypeptides in the 58-68 kDa size range. Phage display and a genomic database were combined to determine the gene encoding the proteins recognized by mAb 3F3. A gene encoding the putative permease of the glucose phosphotransferase system was identified. Genome sequence analysis of strain PG1 revealed two highly similar copies of this gene, resulting from duplication of the chromosomal region carrying the gene. Southern blot analysis demonstrated the presence of this duplication in almost every African strain tested, but not in European strains. DNA analysis revealed that ON/OFF switching is governed by a base substitution occurring upstream of the coding region for the 3F3 epitope. This event generates a stop codon that results in the premature termination of the PtsG protein.

  • variability of a glucose phosphotransferase system permease in Mycoplasma mycoides subsp mycoides small colony
    Microbiology, 2004
    Co-Authors: Patrice Gaurivaud, Michel Solsona, Joakim Westberg, Anja Persson, Dominique Le Grand, Karlerik Johansson, F Poumarat
    Abstract:

    Intraclonal antigenic variation in pathogenic Mycoplasma species is considered an important feature of host-pathogen interaction. Such intraclonal protein variation was observed for the interaction of Mycoplasma mycoides subsp. mycoides Small Colony, the agent of contagious bovine pleuropneumonia, with mAb 3F3. Colony immunostaining allows the definition of 3F3 ON- and 3F3 OFF-type variants, which revert at low frequency. Targets of mAb 3F3 were shown to be surface located, and resided on multiple polypeptides in the 58-68 kDa size range. Phage display and a genomic database were combined to determine the gene encoding the proteins recognized by mAb 3F3. A gene encoding the putative permease of the glucose phosphotransferase system was identified. Genome sequence analysis of strain PG1 revealed two highly similar copies of this gene, resulting from duplication of the chromosomal region carrying the gene. Southern blot analysis demonstrated the presence of this duplication in almost every African strain tested, but not in European strains. DNA analysis revealed that ON/OFF switching is governed by a base substitution occurring upstream of the coding region for the 3F3 epitope. This event generates a stop codon that results in the premature termination of the PtsG protein.

  • assessment of pcr for routine identification of species of the Mycoplasma mycoides cluster in ruminants
    Veterinary Research, 2004
    Co-Authors: Dominique Le Grand, Estelle Saras, Denis Blond, Michel Solsona, F Poumarat
    Abstract:

    DNA amplification techniques offer considerable promise for the identification of Mycoplasma mycoides cluster members. They avoid antigenic cross-reactivity and variability that hamper serological methods. Many sets of primers, specific of these different members and of Mycoplasma putrefaciens, have been proposed. To assess the reliability of some of these PCR tests in routine laboratory diagnostic use, 230 field strains supposed to belong to this group were simultaneously identified by PCR and an antigenic method. The results were well correlated to antigenic identification for M. putrefaciens, but PCR failed to identify respectively 74% and 52% of M. mycoides subsp. mycoides Large Colony type and M. capricolum subsp. capricolum strains. Any identification of M. mycoides subsp. mycoides Small Colony type must be confirmed by two different tests. Difficulties in defining the M. species bovine serogroup 7 were also encountered with both the PCR and immunological methods. The occurrence of putative variable antigen(s) on the Mycoplasma surface may explain part of the identification difficulties encountered with the immunological methods. Mycoplasma mycoides cluster / PCR / ruminants / identification / variable antigen

Edy M Vilei - One of the best experts on this subject based on the ideXlab platform.

  • the origin of the Mycoplasma mycoides cluster coincides with domestication of ruminants
    PLOS ONE, 2012
    Co-Authors: Anne Fischer, Edy M Vilei, Cecilia Muriuki, Martin Heller, Christiane Schnee, Erik Bongcamrudloff, Joerg Jores
    Abstract:

    The 'Mycoplasma mycoides cluster' comprises the ruminant pathogens Mycoplasma mycoides subsp. mycoides the causative agent of contagious bovine pleuropneumonia (CBPP), Mycoplasma capricolum subsp. capripneumoniae the agent of contagious caprine pleuropneumonia (CCPP), Mycoplasma capricolum subsp. capricolum, Mycoplasma leachii and Mycoplasma mycoides subsp. capri. CBPP and CCPP are major livestock diseases and impact the agricultural sector especially in developing countries through reduced food-supply and international trade restrictions. In addition, these diseases are a threat to disease-free countries. We used a multilocus sequence typing (MLST) approach to gain insights into the demographic history of and phylogenetic relationships among the members of the 'M. mycoides cluster'. We collected partial sequences from seven housekeeping genes representing a total of 3,816 base pairs from 118 strains within this cluster, and five strains isolated from wild Caprinae. Strikingly, the origin of the 'M. mycoides cluster' dates to about 10,000 years ago, suggesting that the establishment and spread of the cluster coincided with livestock domestication. In addition, we show that hybridization and recombination may be important factors in the evolutionary history of the cluster.

  • identification of genes coding for b cell antigens of Mycoplasma mycoides subsp mycoides small colony mmmsc by using phage display
    BMC Microbiology, 2009
    Co-Authors: Dubravka Miltiadou, Edy M Vilei, Arshad Mather, Dion H Du Plessis
    Abstract:

    Background Contagious bovine pleuropneumonia (CBPP) is a Mycoplasmal disease caused by Mycoplasma mycoides subsp. mycoides SC (Mmm SC). Since the disease is a serious problem that can affect cattle production in parts of Africa, there is a need for an effective and economical vaccine. Identifying which of the causative agent's proteins trigger potentially protective immune responses is an important step towards developing a subunit vaccine. Accordingly, the purpose of this study was to determine whether phage display combined with bioinformatics could be used to narrow the search for genes that code for potentially immunogenic proteins of Mmm SC. Since the production of IgG2 and IgA are associated with a Th1 cellular immune response which is implicated in protection against CBPP, antigens which elicit these immunoglobulin subclasses may be useful in developing a subunit vaccine.

  • Mycoplasma leachii sp nov as a new species designation for Mycoplasma sp bovine group 7 of leach and reclassification of Mycoplasma mycoides subsp mycoides lc as a serovar of Mycoplasma mycoides subsp capri
    International Journal of Systematic and Evolutionary Microbiology, 2009
    Co-Authors: Lucia Mansosilvan, Edy M Vilei, Steven P. Djordjevic, Francois Thiaucourt
    Abstract:

    The Mycoplasma mycoides cluster consists of six pathogenic Mycoplasmas causing disease in ruminants, which share many genotypic and phenotypic traits. The M. mycoides cluster comprises five recognized taxa: Mycoplasma mycoides subsp. mycoides Small Colony (MmmSC), M. mycoides subsp. mycoides Large Colony (MmmLC), M. mycoides subsp. capri (Mmc), Mycoplasma capricolum subsp. capricolum (Mcc) and M. capricolum subsp. capripneumoniae (Mccp). The group of strains known as Mycoplasma sp. bovine group 7 of Leach (MBG7) has remained unassigned, due to conflicting data obtained by different classification methods. In the present paper, all available data, including recent phylogenetic analyses, have been reviewed, resulting in a proposal for an emended taxonomy of this cluster: (i) the MBG7 strains, although related phylogenetically to M. capricolum, hold sufficient characteristic traits to be assigned as a separate species, i.e. Mycoplasma leachii sp. nov. (type strain, PG50(T) = N29(T) = NCTC 10133(T) = DSM 21131(T)); (ii) MmmLC and Mmc, which can only be distinguished by serological methods and are related more distantly to MmmSC, should be combined into a single subspecies, i.e. Mycoplasma mycoides subsp. capri, leaving M. mycoides subsp. mycoides (MmmSC) as the exclusive designation for the agent of contagious bovine pleuropneumonia. A taxonomic description of M. leachii sp. nov. and emended descriptions of M. mycoides subsp. mycoides and M. mycoides subsp. capri are presented. As a result of these emendments, the M. mycoides cluster will hereafter be composed of five taxa comprising three subclusters, which correspond to the M. mycoides subspecies, the M. capricolum subspecies and the novel species M. leachii

  • Domain analysis of lipoprotein LppQ in Mycoplasma mycoides subsp. mycoides SC
    Antonie van Leeuwenhoek, 2008
    Co-Authors: Laetitia Bonvin-klotz, Edy M Vilei, Kathrin Kühni-boghenbor, Nadine Kapp, Michael H. Stoffel
    Abstract:

    The lipoprotein LppQ is the most prominent antigen of Mycoplasma mycoides subsp. mycoides small colony type (SC) during infection of cattle. This pathogen causes contagious bovine pleuropneumonia (CBPP), a devastating disease of considerable socio-economic importance in many countries worldwide. The dominant antigenicity and high specificity for M. mycoides subsp . mycoides SC of lipoprotein LppQ have been exploited for serological diagnosis and for epidemiological investigations of CBPP. Scanning electron microscopy and immunogold labelling were used to provide ultrastructural evidence that LppQ is located to the cell membrane at the outer surface of M. mycoides subsp . mycoides SC. The selectivity and specificity of this method were demonstrated through discriminating localization of extracellular (i.e., in the zone of contact with host cells) vs. integral membrane domains of LppQ. Thus, our findings support the suggestion that the accessible N-terminal domain of LppQ is surface exposed and such surface localization may be implicated in the pathogenesis of CBPP.

  • cytotoxicity of Mycoplasma mycoides subsp mycoides small colony type to bovine epithelial cells
    Infection and Immunity, 2008
    Co-Authors: Daniela F Bischof, Edy M Vilei, Carole Janis, Giuseppe Bertoni, Joachim Frey
    Abstract:

    The cytotoxicities of various strains of Mycoplasma mycoides subsp. mycoides small colony type (SC), the agent of contagious bovine pleuropneumonia (CBPP), were measured in vitro using embryonic calf nasal epithelial (ECaNEp) cells. Strains isolated from acute cases of CBPP induced high cytotoxicity in the presence of glycerol, concomitant with the release of large amounts of toxic H2O2 that were found to be translocated into the cytoplasms of the host cells by close contact of the Mycoplasma strains with the host cells. Currently used vaccine strains also showed high cytotoxicity and high H2O2 release, indicating that they are attenuated in another virulence attribute. Strains isolated from recent European outbreaks of CBPP with mild clinical signs, which are characterized by a defect in the glycerol uptake system, released small amounts of H2O2 and showed low cytotoxicity to ECaNEp cells. M. mycoides subsp. mycoides SC strain PG1 released large amounts of H2O2 but was only slightly cytotoxic. PG1 was found to have a reduced capacity to bind to ECaNEp cells and was unable to translocate H2O2 into the bovine cells, in contrast to virulent strains that release large amounts of H2O2. Thus, an efficient translocation of H2O2 into host cells is a prerequisite for the cytotoxic effect and requires an intact adhesion mechanism to ensure a close contact between Mycoplasmas and host cells.

Lucia Mansosilvan - One of the best experts on this subject based on the ideXlab platform.

  • free exopolysaccharide from Mycoplasma mycoides subsp mycoides possesses anti inflammatory properties
    Veterinary Research, 2015
    Co-Authors: Philippe Totte, Clothilde Bertin, Lucia Mansosilvan, Carinne Puech, Valerie Rodrigues, Francois Thiaucourt
    Abstract:

    In this study we explored the immunomodulatory properties of highly purified free galactan, the soluble exopolysaccharide secreted by Mycoplasma mycoides subsp. mycoides (Mmm). Galactan was shown to bind to TLR2 but not TLR4 using HEK293 reporter cells and to induce the production of the anti-inflammatory cytokine IL-10 in bovine macrophages, whereas low IL-12p40 and no TNF-α, both pro-inflammatory cytokines, were induced in these cells. In addition, pre-treatment of macrophages with galactan substantially reduced lipopolysaccharide (LPS)-induced production of pro-inflammatory cytokines TNF- and IL-12p40 while increasing LPS-induced secretion of immunosuppressive IL-10. Also, galactan did not activate naive lymphocytes and induced only low production of the Th1 cytokine IFN-γ in Mmm-experienced lymphocytes. Finally, galactan triggered weak recall proliferation of CD4+ T lymphocytes from contagious bovine pleuropneumonia-infected animals despite having a positive effect on the expression of co-stimulatory molecules on macrophages. All together, these results suggest that galactan possesses anti-inflammatory properties and potentially provides Mmm with a mechanism to evade host innate and adaptive cell-mediated immune responses.

  • highly dynamic genomic loci drive the synthesis of two types of capsular or secreted polysaccharides within the Mycoplasma mycoides cluster
    Applied and Environmental Microbiology, 2015
    Co-Authors: Clothilde Bertin, Corinne Pauroblot, Josiane Courtois, Florence Tardy, F Poumarat, Pascal Sirandpugnet, Patrice Gaurivaud, Lucia Mansosilvan, Christine Citti, Francois Thiaucourt
    Abstract:

    Mycoplasmas of the Mycoplasma mycoides cluster are all ruminant pathogens. Mycoplasma mycoides subsp. mycoides is responsible for contagious bovine pleuropneumonia and is known to produce capsular polysaccharide (CPS) and exopolysaccharide (EPS). Previous studies have strongly suggested a role for Mycoplasma mycoides subsp. mycoides polysaccharides in pathogenicity. Mycoplasma mycoides subsp. mycoides-secreted EPS was recently characterized as a β(1→6)-galactofuranose homopolymer (galactan) identical to the capsular product. Here, we extended the characterization of secreted polysaccharides to all other members of the M. mycoides cluster: M. capricolum subsp. capripneumoniae, M. capricolum subsp. capricolum, M. leachii, and M. mycoides subsp. capri (including the LC and Capri serovars). Extracted EPS was characterized by nuclear magnetic resonance, resulting in the identification of a homopolymer of β(1→2)-glucopyranose (glucan) in M. capricolum subsp. capripneumoniae and M. leachii. Monoclonal antibodies specific for this glucan and for the Mycoplasma mycoides subsp. mycoides-secreted galactan were used to detect the two polysaccharides. While M. mycoides subsp. capri strains of serovar LC produced only capsular galactan, no polysaccharide could be detected in strains of serovar Capri. All strains of M. capricolum subsp. capripneumoniae and M. leachii produced glucan CPS and EPS, whereas glucan production and localization varied among M. capricolum subsp. capricolum strains. Genes associated with polysaccharide synthesis and forming a biosynthetic pathway were predicted in all cluster members. These genes were organized in clusters within two loci representing genetic variability hot spots. Phylogenetic analysis showed that some of these genes, notably galE and glf, were acquired via horizontal gene transfer. These findings call for a reassessment of the specificity of the serological tests based on Mycoplasma polysaccharides.

  • characterization of free exopolysaccharides secreted by Mycoplasma mycoides subsp mycoides
    PLOS ONE, 2013
    Co-Authors: Clothilde Bertin, Corinne Pauroblot, Josiane Courtois, Florence Tardy, F Poumarat, Lucia Mansosilvan, Francois Thiaucourt, Dominique Le Grand, Patrice Gaurivaud
    Abstract:

    Contagious bovine pleuropneumonia is a severe respiratory disease of cattle that is caused by a bacterium of the Mycoplasma genus, namely Mycoplasma mycoides subsp. mycoides (Mmm). In the absence of classical virulence determinants, the pathogenicity of Mmm is thought to rely on intrinsic metabolic functions and specific components of the outer cell surface. One of these latter, the capsular polysaccharide galactan has been notably demonstrated to play a role in Mmm persistence and dissemination. The free exopolysaccharides (EPS), also produced by Mmm and shown to circulate in the blood stream of infected cattle, have received little attention so far. Indeed, their characterization has been hindered by the presence of polysaccharide contaminants in the complex Mycoplasma culture medium. In this study, we developed a method to produce large quantities of EPS by transfer of Mycoplasma cells from their complex broth to a chemically defined medium and subsequent purification. NMR analyses revealed that the purified, free EPS had an identical b(12.6)galactofuranosyl structure to that of capsular galactan. We then analyzed intraclonal Mmm variants that produce opaque/ translucent colonies on agar. First, we demonstrated that colony opacity was related to the production of a capsule, as observed by electron microscopy. We then compared the EPS extracts and showed that the non-capsulated, translucent colony variants produced higher amounts of free EPS than the capsulated, opaque colony variants. This phenotypic variation was associated with an antigenic variation of a specific glucose phosphotransferase permease. Finally, we conducted in silico analyses of candidate polysaccharide biosynthetic pathways in order to decipher the potential link between glucose phosphotransferase permease activity and attachment/release of galactan. The co-existence of variants producing alternative forms of galactan (capsular versus free extracellular galactan) and associated with an antigenic switch constitutes a finely tuned mechanism that may be involved in virulence.

  • Mycoplasma mycoides from mycoides small colony to capri a microevolutionary perspective
    BMC Genomics, 2011
    Co-Authors: Francois Thiaucourt, Woubit Salah, Benoit Vacherie, Anne Marie Lomenech, Valerie Barbe, Virginie Dupuy, Marc Breton, Lucia Mansosilvan, Daniel Jacob, Alain Blanchard
    Abstract:

    Background The Mycoplasma mycoides cluster consists of five species or subspecies that are ruminant pathogens. One subspecies, Mycoplasma mycoides subspecies mycoides Small Colony (MmmSC), is the causative agent of contagious bovine pleuropneumonia. Its very close relative, Mycoplasma mycoides subsp. capri (Mmc), is a more ubiquitous pathogen in small ruminants causing mastitis, arthritis, keratitis, pneumonia and septicaemia and is also found as saprophyte in the ear canal. To understand the genetics underlying these phenotypic differences, we compared the MmmSC PG1 type strain genome, which was already available, with the genome of an Mmc field strain (95010) that was sequenced in this study. We also compared the 95010 genome with the recently published genome of another Mmc strain (GM12) to evaluate Mmc strain diversity.

  • Mycoplasma leachii sp nov as a new species designation for Mycoplasma sp bovine group 7 of leach and reclassification of Mycoplasma mycoides subsp mycoides lc as a serovar of Mycoplasma mycoides subsp capri
    International Journal of Systematic and Evolutionary Microbiology, 2009
    Co-Authors: Lucia Mansosilvan, Edy M Vilei, Steven P. Djordjevic, Francois Thiaucourt
    Abstract:

    The Mycoplasma mycoides cluster consists of six pathogenic Mycoplasmas causing disease in ruminants, which share many genotypic and phenotypic traits. The M. mycoides cluster comprises five recognized taxa: Mycoplasma mycoides subsp. mycoides Small Colony (MmmSC), M. mycoides subsp. mycoides Large Colony (MmmLC), M. mycoides subsp. capri (Mmc), Mycoplasma capricolum subsp. capricolum (Mcc) and M. capricolum subsp. capripneumoniae (Mccp). The group of strains known as Mycoplasma sp. bovine group 7 of Leach (MBG7) has remained unassigned, due to conflicting data obtained by different classification methods. In the present paper, all available data, including recent phylogenetic analyses, have been reviewed, resulting in a proposal for an emended taxonomy of this cluster: (i) the MBG7 strains, although related phylogenetically to M. capricolum, hold sufficient characteristic traits to be assigned as a separate species, i.e. Mycoplasma leachii sp. nov. (type strain, PG50(T) = N29(T) = NCTC 10133(T) = DSM 21131(T)); (ii) MmmLC and Mmc, which can only be distinguished by serological methods and are related more distantly to MmmSC, should be combined into a single subspecies, i.e. Mycoplasma mycoides subsp. capri, leaving M. mycoides subsp. mycoides (MmmSC) as the exclusive designation for the agent of contagious bovine pleuropneumonia. A taxonomic description of M. leachii sp. nov. and emended descriptions of M. mycoides subsp. mycoides and M. mycoides subsp. capri are presented. As a result of these emendments, the M. mycoides cluster will hereafter be composed of five taxa comprising three subclusters, which correspond to the M. mycoides subspecies, the M. capricolum subspecies and the novel species M. leachii

Robin A J Nicholas - One of the best experts on this subject based on the ideXlab platform.

  • further evidence to justify reassignment of Mycoplasma mycoides subspecies mycoides large colony type to Mycoplasma mycoides subspecies capri
    Systematic and Applied Microbiology, 2010
    Co-Authors: Masoud Shahram, Robin A J Nicholas, Ann P Wood, Donovan P Kelly
    Abstract:

    Analysis, using the polymerase chain reaction (PCR), restriction enzyme endonuclease analysis (REA), protein profile patterns, random amplification of polymorphic DNA (RAPD) fingerprinting, 16S rRNA gene sequencing and antisera growth inhibition tests, of 22 strains of Mycoplasma mycoides subsp. mycoides Large Colony type (MmmLC) and eight strains of M. mycoides subsp. capri (Mmc) are presented, along with a summary of comparative data from the literature for over 100 strains, all of which supports the reclassification of the MmmLC and Mmc strains into the single subspecies, M. mycoides subspecies capri.

  • experimental infection of goats with an unusual strain of Mycoplasma mycoides subsp capri isolated in jordan
    Journal of Comparative Pathology, 2009
    Co-Authors: Andrea Di Provvido, Massimo Scacchia, Vincenzo Varasano, C Churchward, Roberta Lelli, Waleed Almomani, C. De Caro, Roger D Ayling, G Di Francesco, Robin A J Nicholas
    Abstract:

    Summary Goats were infected experimentally with a Mycoplasma (the ‘‘Irbid’’ strain) isolated previously from a goat with contagious agalactia in northern Jordan. The strain was unusual in that, although it had been identified by molecular methods as Mycoplasma mycoides subsp. mycoides LC/Mycoplasma mycoides subsp. capri, it showed no inhibition of growth by any of the hyperimmune rabbit antisera conventionally used to speciate members of the Mycoplasma mycoides cluster. Animals were infected either intratracheally or by aerosol and placed ‘‘in-contact’’ with other goats. After 2 weeks, those infected intratracheally became febrile, showing a nasal discharge and slight conjunctivitis, followed a week later by respiratory distress and polyarthritis; lesions seen at necropsy included coagulative necrotic pneumonia, fibrinous pleurisy with pleural exudate, and inflammatory exudates, necrosis and fibrosis in the joints. Animals infected by aerosol showed much milder clinical signs, including nasal discharge and occasional swollen joints. In the ‘‘in-contact’’ goats, seroconversion was first seen after 7 weeks, accompanied by coughing and laboured respiration; lesions in this group consisted of fibrinous pneumonia with focal areas of necrosis and abundant pleural exudate. Crown Copyright 2008 Published by Elsevier Ltd. All rights reserved.

  • biofilm grown Mycoplasma mycoides subsp mycoides sc exhibit both phenotypic and genotypic variation compared with planktonic cells
    Veterinary Microbiology, 2008
    Co-Authors: Laura Mcauliffe, Roger D Ayling, Richard J Ellis, Robin A J Nicholas
    Abstract:

    Biofilm formation where bacterial cells adhere to a surface and surround themselves in a polysaccharide matrix is thought to be an important factor in disease initiation and persistence for many bacterial species. We have examined biofilm formation by Mycoplasma mycoides subsp. mycoides small colony using a simple model without an air/liquid interface and have found that adherent Mmm SC was more resistant to many stresses, including heat, osmotic shock and oxidative stress. Biofilms of Mmm SC also exhibited remarkable persistence and were able to survive for up to 20 weeks in stationary phase. Significant variation was seen between Mmm SC strains in their ability to form a biofilm and the morphology of the biofilm produced with some strains unable to produce microcolonies. Proteomic analysis found that a number of proteins linked to adherence were over-expressed in biofilms compared with planktonic cells.

  • identification and characterization of variable number tandem repeat markers for the molecular epidemiological analysis of Mycoplasma mycoides subspecies mycoides sc
    Fems Microbiology Letters, 2007
    Co-Authors: Laura Mcauliffe, Roger D Ayling, Robin A J Nicholas
    Abstract:

    Variable-number tandem-repeat (VNTR) analysis has been developed for the causative agent of contagious bovine pleuropneumonia using the genome of Mycoplasma mycoides subspecies mycoides small colony (M.m.m. SC) PG1. Genome analysis identified 60 VNTRs within the M.m.m. SC genome; however, screening of these VNTRs with a panel of strains identified only three VNTRs that gave allelic variation. Testing of three VNTRs against 39 strains of diverse geographical origin gave 12 different VNTR profiles groups. VNTR analysis may represent a new rapid tool for subtyping M.m.m. SC isolates.

  • assessing the in vitro effectiveness of antimicrobials against Mycoplasma mycoides subsp mycoides small colony type to reduce contagious bovine pleuropneumonia infection
    Antimicrobial Agents and Chemotherapy, 2005
    Co-Authors: Roger D Ayling, John B March, S Bisgaardfrantzen, Kevin Godinho, Robin A J Nicholas
    Abstract:

    In vitro minimum inhibitory concentrations were determined for 21 antimicrobials against 41 isolates of Mycoplasma mycoides subsp. mycoides small-colony type, the cause of contagious bovine pleuropneumonia. Of the antimicrobials used most widely in Africa, oxytetracycline and tilmicosin were effective, while the isolates were resistant to tylosin. These results provide a baseline for monitoring antimicrobial resistance.

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