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Guiraud J, Le Roy C, Rideau F, Sirand-Pugnet P, Lartigue C, Bébéar C, Arfi Y, Pereyre S. Improved transformation efficiency in Mycoplasma hominis enables disruption of the MIB-MIP system targeting human immunoglobulins. Microbiol Spectr 2023; 11:e0187323. [PMID: 37737635 PMCID: PMC10581049 DOI: 10.1128/spectrum.01873-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 07/18/2023] [Indexed: 09/23/2023] Open
Abstract
The pathogenicity of Mycoplasma hominis is poorly understood, mainly due to the absence of efficient genetic tools. A polyethylene glycol-mediated transformation protocol was recently developed for the M. hominis reference strain M132 using the pMT85-Tet plasmid. The transformation efficiency remained low, hampering generation of a large mutant library. In this study, we improved transformation efficiency by designing M. hominis-specific pMT85 derivatives. Using the Gibson Assembly, the Enterococcus-derived tet(M) gene of the pMT85-Tet plasmid was replaced by that of a M. hominis clinical isolate. Next, the Spiroplasma-derived spiralin gene promoter driving tet(M) expression was substituted by one of three putative regulatory regions (RRs): the M. hominis arginine deiminase RR, the M. hominis elongation factor Tu RR, or the 68 bp SynMyco synthetic RR. SynMyco-based construction led to a 100-fold increase in transformation efficiency in M. hominis M132. This construct was also transformed into the M. hominis PG21 reference strain and three other clinical isolates. The transposon insertion locus was determined for 128 M132-transformants. The majority of the impacted coding sequences encoded lipoproteins and proteins involved in DNA repair or in gene transfer. One transposon integration site was in the mycoplasma immunoglobulin protease gene. Phenotypic characterization of the mutant showed complete disruption of the human antibody cleavage ability of the transformant. These results demonstrate that our M. hominis-optimized plasmid can be used to generate large random transposon insertion libraries, enabling future studies of the pathogenicity of M. hominis. IMPORTANCE Mycoplasma hominis is an opportunistic human pathogen, whose physiopathology is poorly understood and for which genetic tools for transposition mutagenesis have been unavailable for years. A PEG-mediated transformation protocol was developed using the pMT85-Tet plasmid, but the transformation efficiency remained low. We designed a modified pMT85-Tet plasmid suitable for M. hominis. The use of a synthetic regulatory region upstream of the antibiotic resistance marker led to a 100-fold increase in the transformation efficiency. The generation and characterization of large transposon mutagenesis mutant libraries will provide insight into M. hominis pathogenesis. We selected a transformant in which the transposon was integrated in the locus encoding the immunoglobulin cleavage system MIB-MIP. Phenotypic characterization showed that the wild-type strain has a functional MIB-MIP system, whereas the mutant strain had lost the ability to cleave human immunoglobulins.
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Affiliation(s)
- Jennifer Guiraud
- Centre national de la recherche scientifique (CNRS), UMR 5234 Fundamental Microbiology and Pathogenicity, University of Bordeaux, Bordeaux, France
- Bacteriology Department, National Reference Centre for Bacterial Sexually Transmitted Infections, Bordeaux University Hospital, Bordeaux, France
| | - Chloé Le Roy
- Centre national de la recherche scientifique (CNRS), UMR 5234 Fundamental Microbiology and Pathogenicity, University of Bordeaux, Bordeaux, France
| | - Fabien Rideau
- INRAE, BFP, UMR 1332, Univ. Bordeaux, Villenave d Ornon, France
| | | | - Carole Lartigue
- INRAE, BFP, UMR 1332, Univ. Bordeaux, Villenave d Ornon, France
| | - Cécile Bébéar
- Centre national de la recherche scientifique (CNRS), UMR 5234 Fundamental Microbiology and Pathogenicity, University of Bordeaux, Bordeaux, France
- Bacteriology Department, National Reference Centre for Bacterial Sexually Transmitted Infections, Bordeaux University Hospital, Bordeaux, France
| | - Yonathan Arfi
- INRAE, BFP, UMR 1332, Univ. Bordeaux, Villenave d Ornon, France
| | - Sabine Pereyre
- Centre national de la recherche scientifique (CNRS), UMR 5234 Fundamental Microbiology and Pathogenicity, University of Bordeaux, Bordeaux, France
- Bacteriology Department, National Reference Centre for Bacterial Sexually Transmitted Infections, Bordeaux University Hospital, Bordeaux, France
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Sommer K, Kowald S, Chopra-Dewasthaly R. Serum Resistance of Mycoplasma agalactiae Strains and Mutants Bearing Different Lipoprotein Profiles. Pathogens 2022; 11:pathogens11091036. [PMID: 36145468 PMCID: PMC9501237 DOI: 10.3390/pathogens11091036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 09/08/2022] [Accepted: 09/09/2022] [Indexed: 12/05/2022] Open
Abstract
In order to spread systemically, resistance against complement and other factors present in serum is an important trait in pathogenic bacteria. The variable proteins of Mycoplasma agalactiae (Vpmas) have been shown to affect differential adhesion, invasion and immune evasion, and undergo high-frequency phase-variation in expression. However, nothing is known about their involvement in M. agalactiae’s serum susceptibility. To evaluate this, the PG2 strain, the GM139 strain and the six Vpma phase-locked mutants (PLMs, PLMU to PLMZ) were tested for their ability to survive in the presence of non-sensitized and sensitized sheep serum, as well as guinea pig complement. Additionally, the reactivity of the sensitized sheep serum was analysed on the strains via western blotting. Overall data demonstrate PG2 strain to be more susceptible to sheep serum compared to the GM139 strain bearing a different Vpma profile. Significant differences were also observed between the different PLMs, with PLMU and PLMX showing the highest serum susceptibility in serum, while the other PLMs expressing longer Vpma proteins were more resistant. The results are in good correlation with previous studies where shorter lipoprotein variants contributed to a higher susceptibility to complement. Since none of the tested strains and PLMs were susceptible to non-sensitized sheep serum, antibodies seem to play an important role in serum killing.
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Genome Editing of Veterinary Relevant Mycoplasmas Using a CRISPR-Cas Base Editor System. Appl Environ Microbiol 2022; 88:e0099622. [PMID: 36000854 PMCID: PMC9469718 DOI: 10.1128/aem.00996-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mycoplasmas are minimal bacteria that infect humans, wildlife, and most economically relevant livestock species. Mycoplasma infections cause a large range of chronic inflammatory diseases, eventually leading to death in some animals. Due to the lack of efficient recombination and genome engineering tools for most species, the production of mutant strains for the identification of virulence factors and the development of improved vaccine strains is limited. Here, we demonstrate the adaptation of an efficient Cas9-Base Editor system to introduce targeted mutations into three major pathogenic species that span the phylogenetic diversity of these bacteria: the avian pathogen Mycoplasma gallisepticum and the two most important bovine mycoplasmas, Mycoplasma bovis and Mycoplasma mycoides subsp. mycoides. As a proof of concept, we successfully used an inducible SpdCas9-pmcDA1 cytosine deaminase system to disrupt several major virulence factors in these pathogens. Various induction times and inducer concentrations were evaluated to optimize editing efficiency. The optimized system was powerful enough to disrupt 54 of 55 insertion sequence transposases in a single experiment. Whole-genome sequencing of the edited strains showed that off-target mutations were limited, suggesting that most variations detected in the edited genomes are Cas9-independent. This effective, rapid, and easy-to-use genetic tool opens a new avenue for the study of these important animal pathogens and likely the entire class Mollicutes. IMPORTANCE Mycoplasmas are minimal pathogenic bacteria that infect a wide range of hosts, including humans, livestock, and wild animals. Major pathogenic species cause acute to chronic infections involving still poorly characterized virulence factors. The lack of precise genome editing tools has hampered functional studies of many species, leaving multiple questions about the molecular basis of their pathogenicity unanswered. Here, we demonstrate the adaptation of a CRISPR-derived base editor for three major pathogenic species: Mycoplasma gallisepticum, Mycoplasma bovis, and Mycoplasma mycoides subsp. mycoides. Several virulence factors were successfully targeted, and we were able to edit up to 54 target sites in a single step. The availability of this efficient and easy-to-use genetic tool will greatly facilitate functional studies of these economically important bacteria.
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Barbosa MS, Marques LM, Timenetsky J, Rosengarten R, Spergser J, Chopra-Dewasthaly R. Host cell interactions of novel antigenic membrane proteins of Mycoplasma agalactiae. BMC Microbiol 2022; 22:93. [PMID: 35395771 PMCID: PMC8991494 DOI: 10.1186/s12866-022-02512-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 03/30/2022] [Indexed: 11/30/2022] Open
Abstract
Background Mycoplasma agalactiae is the main etiological agent of Contagious Agalactia syndrome of small ruminants notifiable to the World Organization for Animal Health. Despite serious economic losses, successful vaccines are unavailable, largely because its colonization and invasion factors are not well understood. This study evaluates the role of two recently identified antigenic proteins (MAG_1560, MAG_6130) and the cytadhesin P40 in pathogenicity related phenotypes. Results Adhesion to HeLa and sheep primary mammary stromal cells (MSC) was evaluated using ELISA, as well as in vitro adhesion assays on monolayer cell cultures. The results demonstrated MAG_6130 as a novel adhesin of M. agalactiae whose capacity to adhere to eukaryotic cells was significantly reduced by specific antiserum. Additionally, these proteins exhibited significant binding to plasminogen and extracellular matrix (ECM) proteins like lactoferrin, fibrinogen and fibronectin, a feature that could potentially support the pathogen in host colonization, tissue migration and immune evasion. Furthermore, these proteins played a detrimental role on the host cell proliferation and viability and were observed to activate pro-apoptotic genes indicating their involvement in cell death when eukaryotic cells were infected with M. agalactiae. Conclusions To summarize, the hypothetical protein corresponding to MAG_6130 has not only been assigned novel adhesion functions but together with P40 it is demonstrated for the first time to bind to lactoferrin and ECM proteins thereby playing important roles in host colonization and pathogenicity. Supplementary Information The online version contains supplementary material available at 10.1186/s12866-022-02512-2.
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Affiliation(s)
- Maysa Santos Barbosa
- Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, Vienna, A-1210, Austria.,Present Address: Department of Microbiology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | - Lucas Miranda Marques
- Present Address: Department of Microbiology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil. .,Multidisciplinary Institute of Health, Federal University of Bahia, Vitória da Conquista, Brazil.
| | - Jorge Timenetsky
- Present Address: Department of Microbiology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | - Renate Rosengarten
- Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, Vienna, A-1210, Austria
| | - Joachim Spergser
- Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, Vienna, A-1210, Austria
| | - Rohini Chopra-Dewasthaly
- Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, Vienna, A-1210, Austria.
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Predominant Single Stable VpmaV Expression in Strain GM139 and Major Differences with Mycoplasma agalactiae Type Strain PG2. Animals (Basel) 2022; 12:ani12030265. [PMID: 35158589 PMCID: PMC8833448 DOI: 10.3390/ani12030265] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/12/2022] [Accepted: 01/17/2022] [Indexed: 01/27/2023] Open
Abstract
Simple Summary MALDI-ToF MS analysis demonstrates major differences between Mycoplasma agalactiae type strain PG2 and strain GM139. Evaluation of the Vpma (variable proteins of M. agalactiae) phenotypic profiles of these two strains reveals that unlike PG2, GM139 expresses a single Vpma, namely VpmaV, and without any visible phase variation. Although the presence of only one Vpma seems to be sufficient for the pathogenesis of the GM139 strain, the absence of phase variation can compromise immune system evasion and spread to other anatomical sites in the host. Abstract Although mycoplasmas have a reduced genome and no cell wall, they have important mechanisms for the antigenic variation in surface lipoproteins that modulate their interactions with the host. Mycoplasma agalactiae, the main etiological agent of contagious agalactia, has a multigene family involved in the high-frequency phase variation in surface lipoproteins called variable proteins of M. agalactiae (Vpmas). The Vpma lipoproteins are involved in the immune evasion, colonization, dissemination, and persistence of M. agalactiae in the host. In this paper, we evaluate the Vpma phenotypic profiles of two different strains of M. agalactiae, namely, GM139 and the type strain PG2, to assess possible correlations between Vpma phase variability and the geographic localization, animal origin, and pathogenicity of these two strains. Using monospecific Vpma antibodies against individual Vpmas in immunoblots, we demonstrate that, unlike PG2, which expresses six Vpma proteins with high-frequency phase variation, colonies of GM139 predominantly express VpmaV and do not exhibit any sectoring phenotype for any Vpma. Since VpmaV is one of the most important Vpmas for cell adhesion and invasion, its predominant sole expression in GM139 without high-frequency variation may be the basis of the differential pathogenicity of GM139 and PG2. Additionally, MALDI-ToF MS analysis also demonstrates significant differences between these two strains and their relatedness with other M. agalactiae strains.
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Rideau F, Le Roy C, Sagné E, Renaudin H, Pereyre S, Henrich B, Dordet-Frisoni E, Citti C, Lartigue C, Bébéar C. Random transposon insertion in the Mycoplasma hominis minimal genome. Sci Rep 2019; 9:13554. [PMID: 31537861 PMCID: PMC6753208 DOI: 10.1038/s41598-019-49919-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 08/30/2019] [Indexed: 11/09/2022] Open
Abstract
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. A genomic analysis of 20 different M. hominis strains revealed a number of putative restriction-modification systems in this species. Despite the presence of these systems, a reproducible polyethylene glycol (PEG)-mediated transformation protocol was successfully developed in this study for three different strains: two clinical isolates and the M132 reference strain. Transformants were generated by transposon mutagenesis with an efficiency of approximately 10-9 transformants/cell/µg plasmid and were shown to carry single or multiple mini-transposons randomly inserted within their genomes. One M132-mutant was observed to carry a single-copy transposon inserted within the gene encoding P75, a protein potentially involved in adhesion. However, no difference in adhesion was observed in cell-assays between this mutant and the M132 parent strain. Whole genome sequencing of mutants carrying multiple copies of the transposon further revealed the occurrence of genomic rearrangements. Overall, this is the first time that genetically modified strains of M. hominis have been obtained by random mutagenesis using a mini-transposon conferring resistance to tetracycline.
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Affiliation(s)
- Fabien Rideau
- University of Bordeaux, USC-EA3671 Mycoplasmal and Chlamydial Infections in Humans, Bordeaux, France.,INRA, USC-EA3671 Mycoplasmal and Chlamydial Infections in Humans, Bordeaux, France
| | - Chloé Le Roy
- University of Bordeaux, USC-EA3671 Mycoplasmal and Chlamydial Infections in Humans, Bordeaux, France.,INRA, USC-EA3671 Mycoplasmal and Chlamydial Infections in Humans, Bordeaux, France
| | - Eveline Sagné
- IHAP, Université de Toulouse, INRA, ENVT, Toulouse, France
| | - Hélène Renaudin
- University of Bordeaux, USC-EA3671 Mycoplasmal and Chlamydial Infections in Humans, Bordeaux, France.,INRA, USC-EA3671 Mycoplasmal and Chlamydial Infections in Humans, Bordeaux, France
| | - Sabine Pereyre
- University of Bordeaux, USC-EA3671 Mycoplasmal and Chlamydial Infections in Humans, Bordeaux, France.,INRA, USC-EA3671 Mycoplasmal and Chlamydial Infections in Humans, Bordeaux, France
| | - Birgit Henrich
- Institute of Medical Microbiology and Hospital Hygiene, Heinrich Heine University, Düsseldorf, Germany
| | | | | | - Carole Lartigue
- INRA, UMR 1332 de Biologie du Fruit et Pathologie, F-33140 Villenave d'Ornon, Gironde, France. .,University of Bordeaux, UMR 1332 de Biologie du Fruit et Pathologie, F-33140 Villenave d'Ornon, Gironde, France.
| | - Cécile Bébéar
- University of Bordeaux, USC-EA3671 Mycoplasmal and Chlamydial Infections in Humans, Bordeaux, France. .,INRA, USC-EA3671 Mycoplasmal and Chlamydial Infections in Humans, Bordeaux, France.
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7
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Josi C, Bürki S, Vidal S, Dordet-Frisoni E, Citti C, Falquet L, Pilo P. Large-Scale Analysis of the Mycoplasma bovis Genome Identified Non-essential, Adhesion- and Virulence-Related Genes. Front Microbiol 2019; 10:2085. [PMID: 31572317 PMCID: PMC6753880 DOI: 10.3389/fmicb.2019.02085] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 08/23/2019] [Indexed: 12/21/2022] Open
Abstract
Mycoplasma bovis 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. The design of new, efficient prophylactic and therapeutic approaches requires a better understanding of the molecular mechanisms responsible for M. bovis pathogenicity. Random transposon mutagenesis has been widely used in Mycoplasma species to identify potential gene functions. Such an approach can also be used to screen genomes and search for essential and non-essential genes for growth. Here, we generated a random transposon mutant library of M. bovis strain JF4278 containing approximately 4000 independent insertion sites. We then coupled high-throughput screening of this mutant library to transposon sequencing and bioinformatic analysis to identify M. bovis non-essential, adhesion- and virulence-related genes. Three hundred and fifty-two genes of M. bovis were assigned as essential for growth in rich medium. Among the remaining non-essential genes, putative virulence-related factors were subsequently identified. The complete mutant library was screened for adhesion using primary bovine mammary gland epithelial cells. Data from this assay resulted in a list of conditional-essential genes with putative adhesion-related functions by identifying non-essential genes for growth that are essential for host cell-adhesion. By individually assessing the adhesion capacity of six selected mutants, two previously unknown factors and the adhesin TrmFO were associated with a reduced adhesion phenotype. Overall, our study (i) uncovers new, putative virulence-related genes; (ii) offers a list of putative adhesion-related factors; and (iii) provides valuable information for vaccine design and for exploring M. bovis biology, pathogenesis, and host-interaction.
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Affiliation(s)
- Christoph Josi
- Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, Institute of Veterinary Bacteriology, University of Bern, Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Sibylle Bürki
- Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, Institute of Veterinary Bacteriology, University of Bern, Bern, Switzerland
| | - Sara Vidal
- Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, Institute of Veterinary Bacteriology, University of Bern, Bern, Switzerland
| | | | - Christine Citti
- UMR 1225, IHAP, Université de Toulouse, INRA, ENVT, Toulouse, France
| | - Laurent Falquet
- Department of Biology, Faculty of Science and Medicine, Swiss Institute of Bioinformatics, University of Fribourg, Fribourg, Switzerland
| | - Paola Pilo
- Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, Institute of Veterinary Bacteriology, University of Bern, Bern, Switzerland
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8
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Montero-Blay A, Miravet-Verde S, Lluch-Senar M, Piñero-Lambea C, Serrano L. SynMyco transposon: engineering transposon vectors for efficient transformation of minimal genomes. DNA Res 2019; 26:327-339. [PMID: 31257417 PMCID: PMC6704405 DOI: 10.1093/dnares/dsz012] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 05/16/2019] [Indexed: 11/17/2022] Open
Abstract
Mycoplasmas are important model organisms for Systems and Synthetic Biology, and are pathogenic to a wide variety of species. Despite their relevance, many of the tools established for genome editing in other microorganisms are not available for Mycoplasmas. The Tn4001 transposon is the reference tool to work with these bacteria, but the transformation efficiencies (TEs) reported for the different species vary substantially. Here, we explore the mechanisms underlying these differences in four Mycoplasma species, Mycoplasma agalactiae, Mycoplasma feriruminatoris, Mycoplasma gallisepticum and Mycoplasma pneumoniae, selected for being representative members of each cluster of the Mycoplasma genus. We found that regulatory regions (RRs) driving the expression of the transposase and the antibiotic resistance marker have a major impact on the TEs. We then designed a synthetic RR termed SynMyco RR to control the expression of the key transposon vector elements. Using this synthetic RR, we were able to increase the TE for M. gallisepticum, M. feriruminatoris and M. agalactiae by 30-, 980- and 1036-fold, respectively. Finally, to illustrate the potential of this new transposon, we performed the first essentiality study in M. agalactiae, basing our study on more than 199,000 genome insertions.
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Affiliation(s)
- Ariadna Montero-Blay
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona, Spain
| | - Samuel Miravet-Verde
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona, Spain
| | - Maria Lluch-Senar
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona, Spain
| | - Carlos Piñero-Lambea
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona, Spain
| | - Luis Serrano
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, Barcelona, Spain.,Universitat Pompeu Fabra (UPF), Barcelona, Spain.,ICREA, Pg. Lluis Companys 23, Barcelona, Spain
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9
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Calcutt MJ, Lysnyansky I, Sachse K, Fox LK, Nicholas RAJ, Ayling RD. Gap analysis of Mycoplasma bovis disease, diagnosis and control: An aid to identify future development requirements. Transbound Emerg Dis 2018; 65 Suppl 1:91-109. [PMID: 29582590 DOI: 10.1111/tbed.12860] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2017] [Indexed: 01/07/2023]
Abstract
There is a worldwide problem of disease caused by Mycoplasma (M.) bovis in cattle; it has a significant detrimental economic and animal welfare impact on cattle rearing. Infection can manifest as a plethora of clinical signs including mastitis, pneumonia, arthritis, keratoconjunctivitis, otitis media and genital disorders that may result in infertility and abortion. Current diagnosis and control information are reviewed and analysed to identify gaps in knowledge of the causative organism in respect of the disease pathology, diagnosis and control methods. The main considerations are as follows: no vaccines are commercially available; antimicrobial resistance is increasing; diagnostic and antimicrobial sensitivity testing needs to be improved; and a pen-side test would facilitate more rapid diagnosis and implementation of treatment with antimicrobials. More data on host susceptibility, stress factors, immune response and infectious dose levels are required. The impact of asymptomatic carriers, M. bovis survival in the environment and the role of wildlife in transmitting the disease also needs investigation. To facilitate development of vaccines, further analysis of more M. bovis genomes, its pathogenic mechanisms, including variable surface proteins, is required, along with reproducible disease models.
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Affiliation(s)
| | | | - K Sachse
- Friedrich-Loeffler-Institut, Jena, Germany.,Department of RNA Bioinformatics and High-Throughput Analysis, Faculty of Mathematics and Computer Science, Friedrich-Schiller-Universität, Jena, Germany
| | - L K Fox
- Washington State University, Pullman, WA, USA
| | | | - R D Ayling
- Animal and Plant Health Agency, Addlestone, UK
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10
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Xer1-independent mechanisms of Vpma phase variation in Mycoplasma agalactiae are triggered by Vpma-specific antibodies. Int J Med Microbiol 2017; 307:443-451. [DOI: 10.1016/j.ijmm.2017.10.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 09/24/2017] [Accepted: 10/23/2017] [Indexed: 11/23/2022] Open
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11
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Hegde S, Zimmermann M, Rosengarten R, Chopra-Dewasthaly R. Novel role of Vpmas as major adhesins of Mycoplasma agalactiae mediating differential cell adhesion and invasion of Vpma expression variants. Int J Med Microbiol 2017; 308:263-270. [PMID: 29229193 DOI: 10.1016/j.ijmm.2017.11.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2017] [Revised: 11/10/2017] [Accepted: 11/21/2017] [Indexed: 11/28/2022] Open
Abstract
Mycoplasma agalactiae exhibits antigenic variation by switching the expression of multiple surface lipoproteins called Vpmas. Although implicated to have a significant influence on the pathogenicity, their exact role in pathogen-host interactions has not been investigated so far. Initial attachment to host cells is regarded as one of the most important steps for colonization but this pathogen lacks the typical mycoplasma attachment organelle. The aim of this study was to determine the role of Vpmas in adhesion of M. agalactiae to host cells. 'Phase-Locked' Mutants (PLMs) steadily expressing single well-characterized Vpma lipoproteins served as ideal tools to evaluate the role of each of the six Vpmas in cytadhesion, which was otherwise not possible due to the high-frequency switching of Vpmas in the wildtype strain PG2. Using in vitro adhesion assays with HeLa and sheep mammary epithelial (MECs) and stromal (MSCs) cells, we could demonstrate differences in the adhesion capabilities of each of the six PLMs compared to the wildtype strain. The PLMV mutant expressing VpmaV exhibited the highest adhesion rate, whereas PLMU, which expresses VpmaU showed the lowest adhesion values explaining the reduced in vivo fitness of PLMU in sheep during experimental intramammary and conjunctival infections. Furthermore, adhesion inhibition assays using Vpma-specific polyclonal antisera were performed to confirm the role of Vpmas in M. agalactiae cytadhesion. This led to a significant decrease (p<0.05) in the adhesion percentage of each PLM. Immunofluorescence staining of TX-114 phase proteins extracted from each PLM showed binding of the respective Vpma to HeLa cells and MECs proving the direct role of Vpmas in cytadhesion. Furthermore, as adhesion is a prerequisite for cell invasion, the ability of the six PLMs to invade HeLa cells was also evaluated using the gentamicin protection assay. The results showed a strong correlation between the adhesion rates and invasion frequencies of the individual PLMs. This is the first report that describes a novel function of Vpma proteins in cell adhesion and invasion. Besides the variability of these proteins causing surface antigenic variation, the newly identified phenotypes are likely to play critical roles in the pathogenicity potential of this ruminant pathogen.
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Affiliation(s)
- Shrilakshmi Hegde
- Institute of Bacteriology, Mycology and Hygiene, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinärplatz 1, A-1210, Vienna, Austria
| | - Martina Zimmermann
- Institute of Bacteriology, Mycology and Hygiene, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinärplatz 1, A-1210, Vienna, Austria
| | - Renate Rosengarten
- Institute of Bacteriology, Mycology and Hygiene, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinärplatz 1, A-1210, Vienna, Austria
| | - Rohini Chopra-Dewasthaly
- Institute of Bacteriology, Mycology and Hygiene, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinärplatz 1, A-1210, Vienna, Austria.
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12
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Chopra-Dewasthaly R, Korb M, Brunthaler R, Ertl R. Comprehensive RNA-Seq Profiling to Evaluate the Sheep Mammary Gland Transcriptome in Response to Experimental Mycoplasma agalactiae Infection. PLoS One 2017; 12:e0170015. [PMID: 28081235 PMCID: PMC5231372 DOI: 10.1371/journal.pone.0170015] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 12/26/2016] [Indexed: 11/19/2022] Open
Abstract
Mycoplasma agalactiae is a worldwide serious pathogen of small ruminants that usually spreads through the mammary route causing acute to subacute mastitis progressing to chronic persistent disease that is hard to eradicate. Knowledge of mechanisms of its pathogenesis and persistence in the mammary gland are still insufficient, especially the host-pathogen interplay that enables it to reside in a chronic subclinical state. This study reports transcriptome profiling of mammary tissue from udders of sheep experimentally infected with M. agalactiae type strain PG2 in comparison with uninfected control animals using Illumina RNA-sequencing (RNA-Seq). Several differentially expressed genes (DEGs) were observed in the infected udders and RT-qPCR analyses of selected DEGs showed their expression profiles to be in agreement with results from RNA-Seq. Gene Ontology (GO) analysis revealed majority of the DEGs to be associated with mycoplasma defense responses that are directly or indirectly involved in host innate and adaptive immune responses. Similar RNA-Seq analyses were also performed with spleen cells of the same sheep to know the specific systemic transcriptome responses. Spleen cells exhibited a comparatively lower number of DEGs suggesting a less prominent host response in this organ. To our knowledge this is the first study that describes host transcriptomics of M. agalactiae infection and the related immune-inflammatory responses. The data provides useful information to further dissect the molecular genetic mechanisms underlying mycoplasma mastitis, which is a prerequisite for designing effective intervention strategies.
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Affiliation(s)
- Rohini Chopra-Dewasthaly
- Division of Clinical Microbiology and Infection Biology, Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine, Veterinaerplatz 1,Vienna, Austria
- * E-mail:
| | - Melanie Korb
- VetCore Facility for Research, University of Veterinary Medicine, Veterinaerplatz 1,Vienna, Austria
| | - René Brunthaler
- Institute of Pathology and Forensic Veterinary Medicine, Department of Pathobiology, University of Veterinary Medicine, Veterinaerplatz 1, Vienna, Austria
| | - Reinhard Ertl
- VetCore Facility for Research, University of Veterinary Medicine, Veterinaerplatz 1,Vienna, Austria
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13
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Hegde S, Zimmermann M, Flöck M, Brunthaler R, Spergser J, Rosengarten R, Chopra-Dewasthaly R. Genetic loci of Mycoplasma agalactiae involved in systemic spreading during experimental intramammary infection of sheep. Vet Res 2016; 47:106. [PMID: 27765069 PMCID: PMC5073455 DOI: 10.1186/s13567-016-0387-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 09/19/2016] [Indexed: 12/17/2022] Open
Abstract
Mycoplasmas are amongst the most successful pathogens of both humans and animals yet the molecular basis of mycoplasma pathogenesis is poorly understood. This is partly due to the lack of classical virulence factors and little similarity to common bacterial pathogenic determinants. Using Mycoplasma agalactiae as a model we initiated research in this direction by screening a transposon mutant library in the natural sheep host using a negative selection method. Having successfully identified putative factors involved in the colonization of local infection and lymphogenic sites, the current study assessed mutants unable to spread systemically in sheep after experimental intramammary infection. Analysis of distant body sites for complete absence of mutants via SSM PCR revealed that additional set of genes, such as pdhB, oppC, oppB, gtsB, MAG1890, MAG5520 and MAG3650 are required for systemic spreading apart from those that were necessary for initial colonization. Additional in vitro studies with the mutants absent at these systemic sites confirmed the potential role of some of the respective gene products concerning their interaction with host cells. Mutants of pdhB, oppC and MAG4460 exhibited significantly slower growth in the presence of HeLa cells in MEM medium. This first attempt to identify genes exclusively required for systemic spreading provides a basis for further in-depth research to understand the exact mechanism of chronicity and persistence of M. agalactiae.
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Affiliation(s)
- Shivanand Hegde
- Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210, Vienna, Austria.,Department of Pathology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Martina Zimmermann
- Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210, Vienna, Austria
| | - Martina Flöck
- Clinic for Ruminants, Department for Farm Animals and Veterinary Public Health, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210, Vienna, Austria
| | - Rene Brunthaler
- Institute of Pathology and Forensic Veterinary Medicine, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210, Vienna, Austria
| | - Joachim Spergser
- Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210, Vienna, Austria
| | - Renate Rosengarten
- Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210, Vienna, Austria
| | - Rohini Chopra-Dewasthaly
- Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210, Vienna, Austria.
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14
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Hegde S, Hegde SM, Rosengarten R, Chopra-Dewasthaly R. Mycoplasma agalactiae Induces Cytopathic Effects in Infected Cells Cultured In Vitro. PLoS One 2016; 11:e0163603. [PMID: 27662492 PMCID: PMC5035028 DOI: 10.1371/journal.pone.0163603] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 09/12/2016] [Indexed: 10/29/2022] Open
Abstract
Mycoplasma agalactiae is the etiological agent of the contagious agalactia syndrome in sheep and goats and causes significant economic losses worldwide. Yet the mechanism of pathogenesis is largely unknown. Even whole-genome sequence analysis of its pathogenic type strain did not lead to any conclusions regarding its virulence or pathogenicity factors. Although inflammation and tissue destruction at the local site of M. agalactiae infection are largely considered as effects of the host immune response, the direct effect of the agent on host cells is not completely understood. The aim of this study was to investigate the effect of M. agalactiae infection on the quality and viability of host cells in vitro. Changes in cell morphology including cell elongation, cytoplasm shrinkage and membrane blebbing were observed in infected HeLa cells. Chromatin condensation and increased caspase-3 cleavage in infected HeLa cells 48 h after infection suggests an apoptosis-like phenomenon in M. agalactiae-infected cells. In compliance with these results, decreased viability and cell lysis of M. agalactiae-infected HeLa cells was also observed. Measurement of the amount of LDH released after M. agalactiae infection revealed a time- and dose-dependent increase in HeLa cell lysis. A significant decrease in LDH released after gentamicin treatment of infected cells confirmed the major role of cytadherent M. agalactiae in inducing host cell lysis. This is the first study illustrating M. agalactiae's induction of cytopathic effects in infected HeLa cells. Further detailed investigation of infected host tissue for apoptotic markers might demonstrate the association between M. agalactiae-induced host cell lysis and the tissue destruction observed during M. agalactiae natural infection.
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Affiliation(s)
- Shrilakshmi Hegde
- Division of Clinical Microbiology and Infection Biology, Institute of Bacteriology, Mycology and Hygiene, Department of Pathobiology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Shivanand Manjunath Hegde
- Division of Clinical Microbiology and Infection Biology, Institute of Bacteriology, Mycology and Hygiene, Department of Pathobiology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Renate Rosengarten
- Division of Clinical Microbiology and Infection Biology, Institute of Bacteriology, Mycology and Hygiene, Department of Pathobiology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Rohini Chopra-Dewasthaly
- Division of Clinical Microbiology and Infection Biology, Institute of Bacteriology, Mycology and Hygiene, Department of Pathobiology, University of Veterinary Medicine Vienna, Vienna, Austria
- * E-mail:
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15
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Bürki S, Frey J, Pilo P. Virulence, persistence and dissemination of Mycoplasma bovis. Vet Microbiol 2015; 179:15-22. [DOI: 10.1016/j.vetmic.2015.02.024] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 02/19/2015] [Accepted: 02/23/2015] [Indexed: 01/17/2023]
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16
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Hegde S, Gabriel C, Kragl M, Chopra-Dewasthaly R. Sheep primary cells as in vitro models to investigate Mycoplasma agalactiae host cell interactions. Pathog Dis 2015; 73:ftv048. [PMID: 26187893 PMCID: PMC4535462 DOI: 10.1093/femspd/ftv048] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/10/2015] [Indexed: 12/31/2022] Open
Abstract
Appropriate infection models are imperative for the understanding of pathogens like mycoplasmas that are known for their strict host and tissue specificity, and lack of suitable cell and small animal models has hindered pathogenicity studies. This is particularly true for the economically important group of ruminant mycoplasmas whose virulence factors need to be elucidated for designing effective intervention strategies. Mycoplasma agalactiae serves as a useful role model especially because it is phylogenetically very close to M. bovis and causes similar symptoms by as yet unknown mechanisms. Here, we successfully prepared and characterized four different primary sheep cell lines, namely the epithelial and stromal cells from the mammary gland and uterus, respectively. Using immunohistochemistry, we identified vimentin and cytokeratin as specific markers to confirm the typical cell phenotypes of these primary cells. Furthermore, M. agalactiae’s consistent adhesion and invasion into these primary cells proves the reliability of these cell models. Mimicking natural infections, mammary epithelial and stromal cells showed higher invasion and adhesion rates compared to the uterine cells as also seen via double immunofluorescence staining. Altogether, we have generated promising in vitro cell models to study host–pathogen interactions of M. agalactiae and related ruminant pathogens in a more authentic manner. The study is an important step forward in developing in vitro models that will facilitate analyses of Mycoplasma agalactiae and related ruminant mycoplasmas' host–pathogen interactions at the molecular level.
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Affiliation(s)
- Shrilakshmi Hegde
- Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, A-1210 Vienna, Austria
| | - Cordula Gabriel
- Institute of Anatomy, Histology and Embryology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, A-1210 Vienna, Austria
| | - Martin Kragl
- Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, A-1210 Vienna, Austria
| | - Rohini Chopra-Dewasthaly
- Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, A-1210 Vienna, Austria;
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17
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Simultaneous Identification of Potential Pathogenicity Factors of Mycoplasma agalactiae in the Natural Ovine Host by Negative Selection. Infect Immun 2015; 83:2751-61. [PMID: 25916984 DOI: 10.1128/iai.00403-15] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 04/16/2015] [Indexed: 11/20/2022] Open
Abstract
Mycoplasmas possess complex pathogenicity determinants that are largely unknown at the molecular level. Mycoplasma agalactiae serves as a useful model to study the molecular basis of mycoplasma pathogenicity. The generation and in vivo screening of a transposon mutant library of M. agalactiae were employed to unravel its host colonization factors. Tn4001mod mutants were sequenced using a novel sequencing method, and functionally heterogeneous pools containing 15 to 19 selected mutants were screened simultaneously through two successive cycles of sheep intramammary infections. A PCR-based negative selection method was employed to identify mutants that failed to colonize the udders and draining lymph nodes in the animals. A total of 14 different mutants found to be absent from ≥ 95% of samples were identified and subsequently verified via a second round of stringent confirmatory screening where 100% absence was considered attenuation. Using this criterion, seven mutants with insertions in genes MAG1050, MAG2540, MAG3390, uhpT, eutD, adhT, and MAG4460 were not recovered from any of the infected animals. Among the attenuated mutants, many contain disruptions in hypothetical genes, implying their previously unknown role in M. agalactiae pathogenicity. These data indicate the putative role of functionally different genes, including hypothetical ones, in the pathogenesis of M. agalactiae. Defining the precise functions of the identified genes is anticipated to increase our understanding of M. agalactiae infections and to develop successful intervention strategies against it.
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18
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Hegde S, Rosengarten R, Chopra-Dewasthaly R. Disruption of the pdhB pyruvate dehydrogenase [corrected] gene affects colony morphology, in vitro growth and cell invasiveness of Mycoplasma agalactiae. PLoS One 2015; 10:e0119706. [PMID: 25799063 PMCID: PMC4370745 DOI: 10.1371/journal.pone.0119706] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 01/14/2015] [Indexed: 12/16/2022] Open
Abstract
The utilization of available substrates, the metabolic potential and the growth rates of bacteria can play significant roles in their pathogenicity. This study concentrates on Mycoplasma agalactiae, which causes significant economic losses through its contribution to contagious agalactia in small ruminants by as yet unknown mechanisms. This lack of knowledge is primarily due to its fastidious growth requirements and the scarcity of genetic tools available for its manipulation and analysis. Transposon mutagenesis of M. agalactiae type strain PG2 resulted in several disruptions throughout the genome. A mutant defective in growth in vitro was found to have a transposon insertion in the pdhB gene, which encodes a component of the pyruvate dehydrogenase complex. This growth difference was quite significant during the actively dividing logarithmic phase but a gradual recovery was observed as the cells approached stationary phase. The mutant also exhibited a different and smaller colony morphology compared to the wild type strain PG2. For complementation, pdhAB was cloned downstream of a strong vpma promoter and upstream of a lacZ reporter gene in a newly constructed complementation vector. When transformed with this vector the pdhB mutant recovered its normal growth and colony morphology. Interestingly, the pdhB mutant also had significantly reduced invasiveness in HeLa cells, as revealed by double immunofluorescence staining. This deficiency was recovered in the complemented strain, which had invasiveness comparable to that of PG2. Taken together, these data indicate that pyruvate dehydrogenase might be an important player in infection with and colonization by M. agalactiae.
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Affiliation(s)
- Shivanand Hegde
- Division of Clinical Microbiology and Infection Biology, Institute of Bacteriology, Mycology and Hygiene, Department of Pathobiology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Renate Rosengarten
- Division of Clinical Microbiology and Infection Biology, Institute of Bacteriology, Mycology and Hygiene, Department of Pathobiology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Rohini Chopra-Dewasthaly
- Division of Clinical Microbiology and Infection Biology, Institute of Bacteriology, Mycology and Hygiene, Department of Pathobiology, University of Veterinary Medicine Vienna, Vienna, Austria
- * E-mail:
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19
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Sharma S, Citti C, Sagné E, Marenda MS, Markham PF, Browning GF. Development and host compatibility of plasmids for two important ruminant pathogens, Mycoplasma bovis and Mycoplasma agalactiae. PLoS One 2015; 10:e0119000. [PMID: 25746296 PMCID: PMC4351888 DOI: 10.1371/journal.pone.0119000] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2014] [Accepted: 01/08/2015] [Indexed: 11/17/2022] Open
Abstract
Mycoplasma bovis is a cause of pneumonia, mastitis, arthritis and otitis media in cattle throughout the world. However, despite its clinical significance, there is a paucity of tools to genetically manipulate it, impeding our capacity to further explore the molecular basis of its virulence. To address this limitation, we developed a series of homologous and heterologous replicable plasmids from M. bovis and M. agalactiae. The shortest replicable oriC plasmid based on the region downstream of dnaA in M. bovis was 247 bp and contained two DnaA boxes, while oriC plasmids based on the region downstream of dnaA in M. agalactiae strains 5632 and PG2 were 219 bp and 217 bp in length, respectively, and contained only a single DnaA box. The efficiency of transformation in M. bovis and M. agalactiae was inversely correlated with the size of the oriC region in the construct, and, in general, homologous oriC plasmids had a higher transformation efficiency than heterologous oriC plasmids. The larger pWholeoriC45 and pMM21-7 plasmids integrated into the genomic oriC region of M. bovis, while the smaller oriC plasmids remained extrachromosomal for up to 20 serial passages in selective media. Although specific gene disruptions were not be achieved in M. bovis in this study, the oriC plasmids developed here could still be useful as tools in complementation studies and for expression of exogenous genes in both M. bovis and M. agalactiae.
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Affiliation(s)
- Shukriti Sharma
- Asia-Pacific Centre for Animal Health, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | | | | | - Marc S Marenda
- Asia-Pacific Centre for Animal Health, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Philip F Markham
- Asia-Pacific Centre for Animal Health, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Glenn F Browning
- Asia-Pacific Centre for Animal Health, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, 3010, Australia
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20
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Li J, Zhang J, Zhang N, Zhang Y, Wu W, Li J. Development of a replicative plasmid for gene expression in Mycoplasma bovis. J Microbiol Methods 2014; 108:12-8. [PMID: 25451459 DOI: 10.1016/j.mimet.2014.11.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 10/30/2014] [Accepted: 11/07/2014] [Indexed: 11/28/2022]
Abstract
Mycoplasma bovis (M. bovis) is a pathogen related to a variety of disease syndromes that result in significant economic losses in the cattle industry. Here, a stable replicative plasmid system is developed for use in M. bovis, utilizing an origin of replication (oriC) region. Additionally, the heterologous protein β-galactosidase and a FLAG tag-fused endogenous protein were successfully expressed by this plasmid system. These findings provide evidence that this oriC-based vector is applicable for the study of M. bovis.
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Affiliation(s)
- Jiahe Li
- Key Laboratory of Zoonosis of Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Jixiang Zhang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Ning Zhang
- Key Laboratory of Zoonosis of Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Yuewei Zhang
- Key Laboratory of Zoonosis of Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Wenxue Wu
- Key Laboratory of Zoonosis of Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, China.
| | - Jinxiang Li
- Chinese Academy of Agricultural Sciences, Beijing, China.
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21
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Shahid MA, Marenda MS, Markham PF, Noormohammadi AH. Development of an oriC vector for use in Mycoplasma synoviae. J Microbiol Methods 2014; 103:70-6. [DOI: 10.1016/j.mimet.2014.05.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2014] [Revised: 05/13/2014] [Accepted: 05/21/2014] [Indexed: 11/30/2022]
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22
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In vitro and in vivo cell invasion and systemic spreading of Mycoplasma agalactiae in the sheep infection model. Int J Med Microbiol 2014; 304:1024-31. [PMID: 25129554 PMCID: PMC4282308 DOI: 10.1016/j.ijmm.2014.07.011] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Revised: 06/25/2014] [Accepted: 07/21/2014] [Indexed: 01/17/2023] Open
Abstract
Generally regarded as extracellular pathogens, molecular mechanisms of mycoplasma persistence, chronicity and disease spread are largely unknown. Mycoplasma agalactiae, an economically important pathogen of small ruminants, causes chronic infections that are difficult to eradicate. Animals continue to shed the agent for several months and even years after the initial infection, in spite of long antibiotic treatment. However, little is known about the strategies that M. agalactiae employs to survive and spread within an immunocompetent host to cause chronic disease. Here, we demonstrate for the first time its ability to invade cultured human (HeLa) and ruminant (BEND and BLF) host cells. Presence of intracellular mycoplasmas is clearly substantiated using differential immunofluorescence technique and quantitative gentamicin invasion assays. Internalized M. agalactiae could survive and exit the cells in a viable state to repopulate the extracellular environment after complete removal of extracellular bacteria with gentamicin. Furthermore, an experimental sheep intramammary infection was carried out to evaluate its systemic spread to organs and host niches distant from the site of initial infection. Positive results obtained via PCR, culture and immunohistochemistry, especially the latter depicting the presence of M. agalactiae in the cytoplasm of mammary duct epithelium and macrophages, clearly provide the first formal proof of M. agalactiae's capability to translocate across the mammary epithelium and systemically disseminate to distant inner organs. Altogether, the findings of these in vitro and in vivo studies indicate that M. agalactiae is capable of entering host cells and this might be the strategy that it employs at a population level to ward off the host immune response and antibiotic action, and to disseminate to new and safer niches to later egress and once again proliferate upon the return of favorable conditions to cause persistent chronic infections.
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23
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Genes found essential in other mycoplasmas are dispensable in Mycoplasma bovis. PLoS One 2014; 9:e97100. [PMID: 24897538 PMCID: PMC4045577 DOI: 10.1371/journal.pone.0097100] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 04/14/2014] [Indexed: 11/19/2022] Open
Abstract
Mycoplasmas are regarded to be useful models for studying the minimum genetic complement required for independent survival of an organism. Mycoplasma bovis is a globally distributed pathogen causing pneumonia, mastitis, arthritis, otitis media and reproductive tract disease, and genome sequences of three strains, the type strain PG45 and two strains isolated in China, have been published. In this study, several Tn4001 based transposon constructs were generated and used to create a M. bovis PG45 insertional mutant library. Direct genome sequencing of 319 independent insertions detected disruptions in 129 genes in M. bovis, 48 of which had homologues in Mycoplasma mycoides subspecies mycoides SC and 99 of which had homologues in Mycoplasma agalactiae. Sixteen genes found to be essential in previous studies on other mycoplasma species were found to be dispensable. Five of these genes have previously been predicted to be part of the core set of 153 essential genes in mycoplasmas. Thus this study has extended the list of non-essential genes of mycoplasmas from that previously generated by studies in other species.
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24
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Experimental infections with Mycoplasma agalactiae identify key factors involved in host-colonization. PLoS One 2014; 9:e93970. [PMID: 24699671 PMCID: PMC3974822 DOI: 10.1371/journal.pone.0093970] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 03/10/2014] [Indexed: 11/19/2022] Open
Abstract
Mechanisms underlying pathogenic processes in mycoplasma infections are poorly understood, mainly because of limited sequence similarities with classical, bacterial virulence factors. Recently, large-scale transposon mutagenesis in the ruminant pathogen Mycoplasma agalactiae identified the NIF locus, including nifS and nifU, as essential for mycoplasma growth in cell culture, while dispensable in axenic media. To evaluate the importance of this locus in vivo, the infectivity of two knock-out mutants was tested upon experimental infection in the natural host. In this model, the parental PG2 strain was able to establish a systemic infection in lactating ewes, colonizing various body sites such as lymph nodes and the mammary gland, even when inoculated at low doses. In these PG2-infected ewes, we observed over the course of infection (i) the development of a specific antibody response and (ii) dynamic changes in expression of M. agalactiae surface variable proteins (Vpma), with multiple Vpma profiles co-existing in the same animal. In contrast and despite a sensitive model, none of the knock-out mutants were able to survive and colonize the host. The extreme avirulent phenotype of the two mutants was further supported by the absence of an IgG response in inoculated animals. The exact role of the NIF locus remains to be elucidated but these data demonstrate that it plays a key role in the infectious process of M. agalactiae and most likely of other pathogenic mycoplasma species as many carry closely related homologs.
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25
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Maglennon GA, Cook BS, Deeney AS, Bossé JT, Peters SE, Langford PR, Maskell DJ, Tucker AW, Wren BW, Rycroft AN. Transposon mutagenesis in Mycoplasma hyopneumoniae using a novel mariner-based system for generating random mutations. Vet Res 2013; 44:124. [PMID: 24359443 PMCID: PMC4028751 DOI: 10.1186/1297-9716-44-124] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 12/02/2013] [Indexed: 11/10/2022] Open
Abstract
Mycoplasma hyopneumoniae is the cause of enzootic pneumonia in pigs, a chronic respiratory disease associated with significant economic losses to swine producers worldwide. The molecular pathogenesis of infection is poorly understood due to the lack of genetic tools to allow manipulation of the organism and more generally for the Mycoplasma genus. The objective of this study was to develop a system for generating random transposon insertion mutants in M. hyopneumoniae that could prove a powerful tool in enabling the pathogenesis of infection to be unraveled. A novel delivery vector was constructed containing a hyperactive C9 mutant of the Himar1 transposase along with a mini transposon containing the tetracycline resistance cassette, tetM. M. hyopneumoniae strain 232 was electroporated with the construct and tetM-expressing transformants selected on agar containing tetracycline. Individual transformants contained single transposon insertions that were stable upon serial passages in broth medium. The insertion sites of 44 individual transformants were determined and confirmed disruption of several M. hyopneumoniae genes. A large pool of over 10 000 mutants was generated that should allow saturation of the M. hyopneumoniae strain 232 genome. This is the first time that transposon mutagenesis has been demonstrated in this important pathogen and could be generally applied for other Mycoplasma species that are intractable to genetic manipulation. The ability to generate random mutant libraries is a powerful tool in the further study of the pathogenesis of this important swine pathogen.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Andrew N Rycroft
- Department of Pathology and Pathogen Biology, The Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, AL9 7TA, UK.
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26
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Maglennon GA, Cook BS, Matthews D, Deeney AS, Bossé JT, Langford PR, Maskell DJ, Tucker AW, Wren BW, Rycroft AN. Development of a self-replicating plasmid system for Mycoplasma hyopneumoniae. Vet Res 2013; 44:63. [PMID: 23895236 PMCID: PMC3765554 DOI: 10.1186/1297-9716-44-63] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Accepted: 07/10/2013] [Indexed: 11/13/2022] Open
Abstract
Mycoplasma hyopneumoniae is a prevalent swine respiratory pathogen that is a major cause of economic loss to pig producers. Control is achieved by a combination of antimicrobials, vaccination and management practices, but current vaccines offer only partial control and there is a need for improved preventative strategies. A major barrier to advances in understanding the pathogenesis of M. hyopneumoniae and in developing new vaccines is the lack of tools to genetically manipulate the organism. We describe the development and optimisation of the first successful plasmid-based system for the genetic manipulation of M. hyopneumoniae. Our artificial plasmids contain the origin of replication (oriC) of M. hyopneumoniae along with tetM, conferring resistance to tetracycline. With these plasmids, we have successfully transformed M. hyopneumoniae strain 232 by electroporation, generating tetracycline resistant organisms. The persistence of extrachromosomal plasmid and maintenance of plasmid DNA over serial passages shows that these artificial plasmids are capable of self-replication in M. hyopneumoniae. In addition to demonstrating the amenability of M. hyopneumoniae to genetic manipulation and in optimising the conditions necessary for successful transformation, we have used this system to determine the minimum functional oriC of M. hyopneumoniae. In doing so, we have developed a plasmid with a small oriC that is stably maintained over multiple passages that may be useful in generating targeted gene disruptions. In conclusion, we have generated a set of plasmids that will be valuable in studies of M. hyopneumoniae pathogenesis and provide a major step forward in the study of this important swine pathogen.
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Affiliation(s)
- Gareth A Maglennon
- Department of Pathology and Pathogen Biology, The Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield AL9 7TA, United Kingdom.
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Zou X, Li Y, Wang Y, Zhou Y, Liu Y, Xin J. Molecular cloning and characterization of a surface-localized adhesion protein in Mycoplasma bovis Hubei-1 strain. PLoS One 2013; 8:e69644. [PMID: 23936063 PMCID: PMC3720590 DOI: 10.1371/journal.pone.0069644] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 06/11/2013] [Indexed: 12/31/2022] Open
Abstract
Mycoplasma bovis (M. bovis) is an important pathogen that causes various bovine diseases, such as mastitis in cows and pneumonia in calves. The surface proteins are generally thought to play a central role in the pathogenesis of this organism. We screened the entire genome of M. bovis Hubei-1 and discovered a gene named vpmaX that encodes the 25 kDa variable surface lipoprotein A (VpmaX). Sequence analysis revealed that VpmaX contains several repetitive units and a typical bacterial lipoprotein signal sequence. The vpmaX gene was cloned and expressed in E. coli to obtain recombinant VpmaX (rVpmaX). Western blot analysis using a rabbit antibody against rVpmaX demonstrated that VpmaX is a membrane protein. Immunostaining visualized via confocal laser scanning microscopy showed that rVpmaX was able to adhere to embryonic bovine lung cells (EBL), and this was also confirmed by a sandwich ELISA. In summary, a surface-localized adhesion protein was identified in M. bovis Hubei-1.
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Affiliation(s)
- Xiaohui Zou
- National Contagious Bovine Pleuropneumonia Reference Laboratory, Division of Bacterial Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, CAAS, Harbin, China
| | - Yuan Li
- National Contagious Bovine Pleuropneumonia Reference Laboratory, Division of Bacterial Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, CAAS, Harbin, China
| | - Yang Wang
- National Contagious Bovine Pleuropneumonia Reference Laboratory, Division of Bacterial Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, CAAS, Harbin, China
| | - Yumei Zhou
- National Contagious Bovine Pleuropneumonia Reference Laboratory, Division of Bacterial Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, CAAS, Harbin, China
| | - Yang Liu
- National Engineering Research Center of Veterinary Biologics, Harbin, China
| | - Jiuqing Xin
- National Contagious Bovine Pleuropneumonia Reference Laboratory, Division of Bacterial Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, CAAS, Harbin, China
- * E-mail:
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Chopra-Dewasthaly R, Baumgartner M, Gamper E, Innerebner C, Zimmermann M, Schilcher F, Tichy A, Winter P, Jechlinger W, Rosengarten R, Spergser J. Role of Vpma phase variation in Mycoplasma agalactiae pathogenesis. ACTA ACUST UNITED AC 2012; 66:307-22. [PMID: 22809092 DOI: 10.1111/j.1574-695x.2012.01010.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Revised: 06/02/2012] [Accepted: 07/02/2012] [Indexed: 12/01/2022]
Abstract
Compared with other bacterial pathogens, the molecular mechanisms of mycoplasma pathogenicity are largely unknown. Several studies in the past have shown that pathogenic mycoplasmas are equipped with sophisticated genetic systems that allow them to undergo high-frequency surface antigenic variations. Although never clearly proven, these variable mycoplasma surface components are often implicated in host immune evasion and adaptation. Vpma surface lipoproteins of the ruminant pathogen Mycoplasma agalactiae are encoded on a genomic pathogenicity island-like locus and are considered as one of the well-characterized model systems of mycoplasma surface antigenic variation. The present study assesses the role of these phase-variable Vpmas in the molecular pathogenesis of M. agalactiae by testing the wild-type strain PG2 in comparison with the xer1-disrupted Vpma 'phase-locked' mutants in sheep infection models. The data clearly illustrate that although Xer1 recombinase is not a virulence factor of M. agalactiae and Vpma phase variation is not necessary for establishing an infection, it might critically influence the survival and persistence of the pathogen under natural field conditions, mainly due to a better capacity for dissemination and evoking systemic responses. This is the first study where mycoplasma 'phase-locked' mutants are tested in vivo to elucidate the role of phase variation during infection.
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Affiliation(s)
- Rohini Chopra-Dewasthaly
- Institute of Bacteriology, Mycology and Hygiene, Department of Pathobiology, University of Veterinary Medicine, Vienna, Austria.
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Kent BN, Foecking MF, Calcutt MJ. Development of a novel plasmid as a shuttle vector for heterologous gene expression in Mycoplasma yeatsii. J Microbiol Methods 2012; 91:121-7. [PMID: 22968084 DOI: 10.1016/j.mimet.2012.07.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2012] [Revised: 07/20/2012] [Accepted: 07/23/2012] [Indexed: 10/28/2022]
Abstract
A circular plasmid, pMyBK1, was detected in Mycoplasma yeatsii strain GIH(T). Analysis of the sequence of the 3432-bp replicon identified two predicted open reading frames (ORFs), one with sequence similarity to multiple plasmid mobilization proteins and one that matches only to hypothetical ORFs encoded by integrated chromosomal elements in the sequenced genomes of two Mycoplasma species. Shuttle vectors were constructed in Escherichia coli which could be introduced into M. yeatsii at high efficiency (10(4)-10(5) per μg DNA) by electroporation. Independent deletion analysis of the two ORFs disclosed that whereas mob was dispensable, orf2 was necessary for plasmid replication or maintenance. The absence of plasmid-encoded database matches for ORF2 indicates that pMyBK1 represents a novel plasmid family. One shuttle vector was used to demonstrate heterologous expression of the Mycoplasma fermentans malp gene and was stable during multiple passages. The host-plasmid system described has potential application for genetic manipulation in a genus for which few replicative vectors are available.
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Affiliation(s)
- Bethany N Kent
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA
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Comparative analysis of gene content evolution in phytoplasmas and mycoplasmas. PLoS One 2012; 7:e34407. [PMID: 22479625 PMCID: PMC3313985 DOI: 10.1371/journal.pone.0034407] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Accepted: 03/01/2012] [Indexed: 11/21/2022] Open
Abstract
Phytoplasmas and mycoplasmas are two groups of important pathogens in the bacterial class Mollicutes. Because of their economical and clinical importance, these obligate pathogens have attracted much research attention. However, difficulties involved in the empirical study of these bacteria, particularly the fact that phytoplasmas have not yet been successfully cultivated outside of their hosts despite decades of attempts, have greatly hampered research progress. With the rapid advancements in genome sequencing, comparative genome analysis provides a new approach to facilitate our understanding of these bacteria. In this study, our main focus is to investigate the evolution of gene content in phytoplasmas, mycoplasmas, and their common ancestor. By using a phylogenetic framework for comparative analysis of 12 complete genome sequences, we characterized the putative gains and losses of genes in these obligate parasites. Our results demonstrated that the degradation of metabolic capacities in these bacteria has occurred predominantly in the common ancestor of Mollicutes, prior to the evolutionary split of phytoplasmas and mycoplasmas. Furthermore, we identified a list of genes that are acquired by the common ancestor of phytoplasmas and are conserved across all strains with complete genome sequences available. These genes include several putative effectors for the interactions with hosts and may be good candidates for future functional characterization.
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Skapski A, Hygonenq MC, Sagné E, Guiral S, Citti C, Baranowski E. Genome-scale analysis of Mycoplasma agalactiae loci involved in interaction with host cells. PLoS One 2011; 6:e25291. [PMID: 21966487 PMCID: PMC3179502 DOI: 10.1371/journal.pone.0025291] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Accepted: 08/31/2011] [Indexed: 11/19/2022] Open
Abstract
Mycoplasma agalactiae is an important pathogen of small ruminants, in which it causes contagious agalactia. It belongs to a large group of “minimal bacteria” with a small genome and reduced metabolic capacities that are dependent on their host for nutrients. Mycoplasma survival thus relies on intimate contact with host cells, but little is known about the factors involved in these interactions or in the more general infectious process. To address this issue, an assay based on goat epithelial and fibroblastic cells was used to screen a M. agalactiae knockout mutant library. Mutants with reduced growth capacities in cell culture were selected and 62 genomic loci were identified as contributing to this phenotype. As expected for minimal bacteria, “transport and metabolism” was the functional category most commonly implicated in this phenotype, but 50% of the selected mutants were disrupted in coding sequences (CDSs) with unknown functions, with surface lipoproteins being most commonly represented in this category. Since mycoplasmas lack a cell wall, lipoproteins are likely to be important in interactions with the host. A few intergenic regions were also identified that may act as regulatory sequences under co-culture conditions. Interestingly, some mutants mapped to gene clusters that are highly conserved across mycoplasma species but located in different positions. One of these clusters was found in a transcriptionally active region of the M. agalactiae chromosome, downstream of a cryptic promoter. A possible scenario for the evolution of these loci is discussed. Finally, several CDSs identified here are conserved in other important pathogenic mycoplasmas, and some were involved in horizontal gene transfer with phylogenetically distant species. These results provide a basis for further deciphering functions mediating mycoplasma-host interactions.
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Affiliation(s)
- Agnès Skapski
- INRA, UMR1225, IHAP, Toulouse, France
- Université de Toulouse, INP, ENVT, UMR1225, IHAP, Toulouse, France
| | - Marie-Claude Hygonenq
- INRA, UMR1225, IHAP, Toulouse, France
- Université de Toulouse, INP, ENVT, UMR1225, IHAP, Toulouse, France
| | - Eveline Sagné
- INRA, UMR1225, IHAP, Toulouse, France
- Université de Toulouse, INP, ENVT, UMR1225, IHAP, Toulouse, France
| | - Sébastien Guiral
- INRA, UMR1225, IHAP, Toulouse, France
- Université de Toulouse, INP, ENVT, UMR1225, IHAP, Toulouse, France
| | - Christine Citti
- INRA, UMR1225, IHAP, Toulouse, France
- Université de Toulouse, INP, ENVT, UMR1225, IHAP, Toulouse, France
| | - Eric Baranowski
- INRA, UMR1225, IHAP, Toulouse, France
- Université de Toulouse, INP, ENVT, UMR1225, IHAP, Toulouse, France
- * E-mail:
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Enhancement of targeted homologous recombination in Mycoplasma mycoides subsp. capri by inclusion of heterologous recA. Appl Environ Microbiol 2010; 76:6951-4. [PMID: 20802067 DOI: 10.1128/aem.00056-10] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A suicide plasmid, pExp1-ctpA::tetM-recAec, employing recA from Escherichia coli and tetM as a selection marker, was used to generate ctpA knockout mutants in Mycoplasma mycoides subsp. capri through targeted gene disruption. Inclusion of E. coli recA greatly enhanced both the consistency and the recovery of mutants generated by homologous recombination.
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Xer1-mediated site-specific DNA inversions and excisions in Mycoplasma agalactiae. J Bacteriol 2010; 192:4462-73. [PMID: 20562305 DOI: 10.1128/jb.01537-09] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Surface antigen variation in Mycoplasma agalactiae, the etiologic agent of contagious agalactia in sheep and goats, is governed by site-specific recombination within the vpma multigene locus encoding the Vpma family of variable surface lipoproteins. This high-frequency Vpma phase switching was previously shown to be mediated by a Xer1 recombinase encoded adjacent to the vpma locus. In this study, it was demonstrated in Escherichia coli that the Xer1 recombinase is responsible for catalyzing vpma gene inversions between recombination sites (RS) located in the 5'-untranslated region (UTR) in all six vpma genes, causing cleavage and strand exchange within a 21-bp conserved region that serves as a recognition sequence. It was further shown that the outcome of the site-specific recombination event depends on the orientation of the two vpma RS, as direct or inverted repeats. While recombination between inverted vpma RS led to inversions, recombination between direct repeat vpma RS led to excisions. Using a newly developed excision assay based on the lacZ reporter system, we were able to successfully demonstrate under native conditions that such Xer1-mediated excisions can indeed also occur in the M. agalactiae type strain PG2, whereas they were not observed in the control xer1-disrupted VpmaY phase-locked mutant (PLMY), which lacks Xer1 recombinase. Unless there are specific regulatory mechanisms preventing such excisions, this might be the cost that the pathogen has to render at the population level for maintaining this high-frequency phase variation machinery.
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Abstract
Most gene knockouts in mycoplasmas are achieved through labor-intensive transposon mutagenesis. Here, we describe a method for making targeted deletions in Mycoplasma pneumoniae by use of homologous recombination. In this method, M. pneumoniae is transformed with a plasmid carrying an antibiotic resistance marker flanked by 1-kb regions surrounding the target gene. Following selection for the antibiotic resistance, colonies are screened for double crossovers which indicate complete deletion of the target open reading frame.
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35
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Critical role of dispensable genes in Mycoplasma agalactiae interaction with mammalian cells. Infect Immun 2010; 78:1542-51. [PMID: 20123713 DOI: 10.1128/iai.01195-09] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Mycoplasmas are minimal bacteria whose genomes barely exceed the smallest amount of information required to sustain autonomous life. Despite this apparent simplicity, several mycoplasmas are successful pathogens of humans and animals, in which they establish intimate interactions with epithelial cells at mucosal surfaces. To identify biological functions mediating mycoplasma interactions with mammalian cells, we produced a library of transposon knockout mutants in the ruminant pathogen Mycoplasma agalactiae and used this library to identify mutants displaying a growth-deficient pheonotype in cell culture. M. agalactiae mutants displaying a 3-fold reduction in CFU titers to nearly complete extinction in coculture with HeLa cells were identified. Mapping of transposon insertion sites revealed 18 genomic regions putatively involved in the interaction of M. agalactiae with HeLa cells. Several of these regions encode proteins with features of membrane lipoproteins and/or were involved in horizontal gene transfer with phylogenetically distant pathogenic mycoplasmas of ruminants. Two mutants with the most extreme phenotype carry a transposon in a genomic region designated the NIF locus which encodes homologues of SufS and SufU, two proteins presumably involved in [Fe-S] cluster biosynthesis in Gram-positive bacteria. Complementation studies confirmed the conditional essentiality of the NIF locus, which was found to be critical for proliferation in the presence of HeLa cells and several other mammalian cell lines but dispensable for axenic growth. While our results raised questions regarding essential functions in mycoplasmas, they also provide a means for studying the role of mycoplasmas as minimal pathogens.
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Breton M, Sagné E, Duret S, Béven L, Citti C, Renaudin J. First report of a tetracycline-inducible gene expression system for mollicutes. MICROBIOLOGY-SGM 2009; 156:198-205. [PMID: 19797362 DOI: 10.1099/mic.0.034074-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Inducible promoter systems are powerful tools for studying gene function in prokaryotes but have never been shown to function in mollicutes. In this study we evaluated the efficacy of the tetracycline-inducible promoter Pxyl/tetO(2) from Bacillus subtilis in controlling gene expression in two mollicutes, the plant pathogen Spiroplasma citri and the animal pathogen Mycoplasma agalactiae. An S. citri plasmid carrying the spiralin gene under the control of the xyl/tetO(2) tetracycline-inducible promoter and the TetR repressor gene under the control of a constitutive spiroplasmal promoter was introduced into the spiralin-less S. citri mutant GII3-9a3. In the absence of tetracycline, expression of TetR almost completely abolished expression of spiralin from the xyl/tetO(2) promoter. Adding tetracycline (>50 ng ml(-1)) to the medium induced high-level expression of spiralin. Interestingly, inducible expression of spiralin was also detected in vivo: in S. citri-infected leafhoppers fed on tetracycline-containing medium and in S. citri-infected plants watered with tetracycline. A similar construct was introduced into the M. agalactiae chromosome through transposition. Tetracycline-induced expression of spiralin proved the TetR-Pxyl/tetO(2) system to be functional in the ruminant pathogen, suggesting that this tetracycline-inducible promoter system might be of general use in mollicutes.
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Affiliation(s)
- Marc Breton
- Université de Bordeaux 2, UMR 1090 Génomique Diversité Pouvoir Pathogène, F-33883 Villenave d'Ornon, France.,INRA, UMR 1090 Génomique Diversité et Pouvoir Pathogène, F-33883 Villenave d'Ornon, France
| | - Evelyne Sagné
- Université de Toulouse, ENVT, UMR 1225 Interactions hôtes agents pathogènes, F-31076 Toulouse, France.,INRA, UMR 1225 Interactions hôtes agents pathogènes, F-31076 Toulouse, France
| | - Sybille Duret
- Université de Bordeaux 2, UMR 1090 Génomique Diversité Pouvoir Pathogène, F-33883 Villenave d'Ornon, France.,INRA, UMR 1090 Génomique Diversité et Pouvoir Pathogène, F-33883 Villenave d'Ornon, France
| | - Laure Béven
- Université de Bordeaux 2, UMR 1090 Génomique Diversité Pouvoir Pathogène, F-33883 Villenave d'Ornon, France.,INRA, UMR 1090 Génomique Diversité et Pouvoir Pathogène, F-33883 Villenave d'Ornon, France
| | - Christine Citti
- Université de Toulouse, ENVT, UMR 1225 Interactions hôtes agents pathogènes, F-31076 Toulouse, France.,INRA, UMR 1225 Interactions hôtes agents pathogènes, F-31076 Toulouse, France
| | - Joël Renaudin
- Université de Bordeaux 2, UMR 1090 Génomique Diversité Pouvoir Pathogène, F-33883 Villenave d'Ornon, France.,INRA, UMR 1090 Génomique Diversité et Pouvoir Pathogène, F-33883 Villenave d'Ornon, France
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Lysnyansky I, Calcutt MJ, Ben-Barak I, Ron Y, Levisohn S, Methé BA, Yogev D. Molecular characterization of newly identified IS3, IS4and IS30insertion sequence-like elements inMycoplasma bovisand their possible roles in genome plasticity. FEMS Microbiol Lett 2009; 294:172-82. [DOI: 10.1111/j.1574-6968.2009.01562.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Chopra-Dewasthaly R, Citti C, Glew MD, Zimmermann M, Rosengarten R, Jechlinger W. Phase-locked mutants of Mycoplasma agalactiae: defining the molecular switch of high-frequency Vpma antigenic variation. Mol Microbiol 2008; 67:1196-210. [PMID: 18248580 PMCID: PMC2268961 DOI: 10.1111/j.1365-2958.2007.06103.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mycoplasma agalactiae, an important pathogen of small ruminants, exhibits antigenic diversity by switching the expression of multiple surface lipoproteins called Vpmas (Variable proteins of M. agalactiae). Although phase variation has been shown to play important roles in many host–pathogen interactions, the biological significance and the mechanism of Vpma oscillations remain largely unclear. Here, we demonstrate that all six Vpma proteins are expressed in the type strain PG2 and all undergo phase variation at an unusually high frequency. Furthermore, targeted gene disruption of the xer1 gene encoding a putative site-specific recombinase adjacent to the vpma locus was accomplished via homologous recombination using a replicon-based vector. Inactivation of xer1 abolished further Vpma switching and the ‘phase-locked’ mutants (PLMs) continued to steadily express only a single Vpma product. Complementation of the wild-type xer1 gene in PLMs restored Vpma phase variation thereby proving that Xer1 is essential for vpma inversions. The study is not only instrumental in enhancing our ability to understand the role of Vpmas in M. agalactiae infections but also provides useful molecular approaches to study potential disease factors in other ‘difficult-to-manipulate’ mycoplasmas.
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Affiliation(s)
- Rohini Chopra-Dewasthaly
- Institute of Bacteriology, Mycology and Hygiene, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinärplatz 1, A-1210 Vienna, Austria.
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Perez-Casal J, Prysliak T. Detection of antibodies against the Mycoplasma bovis glyceraldehyde-3-phosphate dehydrogenase protein in beef cattle. Microb Pathog 2007; 43:189-97. [PMID: 17689221 DOI: 10.1016/j.micpath.2007.05.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2007] [Accepted: 05/10/2007] [Indexed: 11/21/2022]
Abstract
Diseases caused by Mycoplasma bovis are an important source of financial losses for beef and dairy cattle producers. Antigenic variation in M. bovis hinders the production of effective vaccines and although there are few vaccines available, they are prepared from bacteria obtained from few isolates potentially limiting their effectiveness. Thus, to develop a vaccine that protects against all M. bovis isolates, it is necessary to use a common antigen that shows less or no antigenic variation. We have isolated the gap gene of M. bovis encoding for glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and showed that cattle colonized with M. bovis were able to mount an immune response to GAPDH. Using restriction-fragment length polymorphism (RFLP) of several M. bovis gap genes amplified by PCR, we were able to detect small intragenic variations that allowed us to classify the genes into two groups without changing the antigenic makeup of the proteins. The immune responses detected in cattle combined with the antigenic conservation of the proteins suggest that the M. bovis GAPDH protein could be a potential target for development of a more effective vaccine against all M. bovis isolates.
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Affiliation(s)
- Jose Perez-Casal
- Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E3.
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40
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Chopra-Dewasthaly R, Marenda M, Rosengarten R, Jechlinger W, Citti C. Construction of the first shuttle vectors for gene cloning and homologous recombination in Mycoplasma agalactiae. FEMS Microbiol Lett 2005; 253:89-94. [PMID: 16213670 PMCID: PMC6485543 DOI: 10.1016/j.femsle.2005.09.021] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2005] [Revised: 09/01/2005] [Accepted: 09/14/2005] [Indexed: 11/16/2022] Open
Abstract
Mycoplasma agalactiae is a worldwide ruminant pathogen that causes significant economic losses by inflicting contagious agalactia in sheep and goats. The development of efficient control strategies requires a better understanding of the mycoplasma factors that promote successful infection. However, lack of genetic tools has been a major impediment in studying the pathogenic mechanisms of M. agalactiae. This study describes the identification and cloning of the M. agalactiae origin of replication (oriC) in order to construct the first shuttle vectors for targeted gene disruption, gene complementation and expression studies. Additionally, this report provides the first evidence of the occurrence of homologous recombination and the functionality of heterologous tetM determinant in this pathogen.
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Affiliation(s)
- Rohini Chopra-Dewasthaly
- Institute of Bacteriology, Mycology and Hygiene, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinärplatz 1, A-1210 Vienna, Austria
| | - Marc Marenda
- UMR 1225 INRA-ENVT, Ecole Nationale Vétérinaire, 23 Chemin des Capelles, BP 87614, F-31076 Toulouse Cedex 3, France
| | - Renate Rosengarten
- Institute of Bacteriology, Mycology and Hygiene, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinärplatz 1, A-1210 Vienna, Austria
| | - Wolfgang Jechlinger
- Institute of Bacteriology, Mycology and Hygiene, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinärplatz 1, A-1210 Vienna, Austria
| | - Christine Citti
- Institute of Bacteriology, Mycology and Hygiene, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinärplatz 1, A-1210 Vienna, Austria
- UMR 1225 INRA-ENVT, Ecole Nationale Vétérinaire, 23 Chemin des Capelles, BP 87614, F-31076 Toulouse Cedex 3, France
- Corresponding author. Tel.: +33 5 61193856; fax: +33 5 61193273. (C. Citti)
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