Mycoplasma invasion into host cells: An integrated model of infection strategy

Mycoplasma belong to the genus Mollicutes and are notable for their small genome sizes (500-1300 kb) and limited biosynthetic capabilities. They exhibit pathogenicity by invading various cell types to survive as intracellular pathogens. Adhesion is a crucial prerequisite for successful invasion and is orchestrated by the interplay between mycoplasma surface adhesins and specific receptors on the host cell membrane. Invasion relies heavily on clathrin- and caveolae-mediated internalization, accompanied by multiple activated kinases, cytoskeletal rearrangement, and a myriad of morphological alterations, such as membrane invagination, nuclear hypertrophy and aggregation, cytoplasmic edema, and vacuolization. Once mycoplasma successfully invade host cells, they establish resilient sanctuaries in vesicles, cytoplasm, perinuclear regions, and the nucleus, wherein specific environmental conditions favor long-term survival. Although lysosomal degradation and autophagy can eliminate most invading mycoplasmas, some viable bacteria can be released into the extracellular environment via exocytosis, a crucial factor in the prolonging infection persistence. This review explores the intricate mechanisms by which mycoplasma invades host cells and perpetuates their elusive survival, with the aim of highlighting the challenge of eradicating this enigmatic bacterium.

Mycoplasma DnaK increases DNA copy number variants in vivo

The human microbiota affects critical cellular functions, although the responsible mechanism(s) is still poorly understood. In this regard, we previously showed that Mycoplasma fermentans DnaK, an HSP70 chaperone protein, hampers the activity of important cellular proteins responsible for DNA integrity. Here, we describe a novel DnaK knock-in mouse model generated in our laboratory to study the effect of M. fermentans DnaK expression in vivo. By using an array-based comparative genomic hybridization assay, we demonstrate that exposure to DnaK was associated with a higher number of DNA copy number variants (CNVs) indicative of unbalanced chromosomal alterations, together with reduced fertility and a high rate of fetal abnormalities. Consistent with their implication in genetic disorders, one of these CNVs caused a homozygous Grid2 deletion, resulting in an aberrant ataxic phenotype that recapitulates the extensive biallelic deletion in the Grid2 gene classified in humans as autosomal recessive spinocerebellar ataxia 18. Our data highlight a connection between components of the human urogenital tract microbiota, namely Mycoplasmas, and genetic abnormalities in the form of DNA CNVs, with obvious relevant medical, diagnostic, and therapeutic implications.

Lnc90386 Sponges miR-33-5p to Mediate Mycoplasma gallisepticum-Induced Inflammation and Apoptosis in Chickens via the JNK Pathway

Mycoplasma gallisepticum (MG) is one of the most important pathogens, that causes chronic respiratory disease (CRD) in chickens. Long non-coding RNAs (lncRNAs) are emerging as new regulators for many diseases and some lncRNAs can function as competing endogenous RNAs (ceRNAs) to regulate mRNAs by competitively binding to miRNAs. Here, we found that miR-33-5p was significantly up-regulated both in MG-infected chicken embryonic lungs and chicken embryo fibroblast cells (DF-1), and Lnc90386 negatively correlated with miR-33-5p. miR-33-5p, as a new regulator for MG infection, repressed apoptosis, inflammatory factors in DF-1 cells by targeting JNK1. Further analyses showed that Lnc90386 sponged miR-33-5p to weaken its inhibitory effect on JNK1, forming the ceRNA regulatory network. Furthermore, knockdown of Lnc90386 significantly inhibited apoptosis and inflammatory factors, and promoted DF-1 cells proliferation. However, co-treatment with miR-33-5p inhibitor and Lnc90386 siRNA showed that knockdown of Lnc90386 could partially eliminate the inhibiting effect of miR-33-5p inhibitor on inflammation, cell apoptosis and proliferation. In conclusion, Lnc90386 sponges miR-33-5p to defend against MG infection by inhibiting the JNK signaling pathway.

Innate immune response in bovine neutrophils stimulated with Mycoplasma bovis

Mycoplasma bovis (M. bovis) is a significant worldwide pathogen of cattle. Neutrophils have an important role in the innate immune response during infection with M. bovis. However, even though neutrophils accumulate in M. bovis infection, the interaction of M. bovis and neutrophils has not been fully elucidated. We attempted to elucidate the innate immune response of neutrophils stimulated with M. bovis and evaluate the transcriptome and functional analysis of bovine neutrophils stimulated with M. bovis. Proinflammatory cytokines, such as inducible nitric oxide (iNOS), which was the most increased gene in transcriptome analysis, were increased in quantitative polymerase chain reaction analysis of bovine neutrophils stimulated with live or heat-killed M. bovis. Nitric oxide and intracellular reactive oxygen species production of neutrophils stimulated with M. bovis was significantly increased. Neutrophils stimulated with M. bovis showed an increased ratio of nonapoptotic cell death compared to unstimulated controls. We demonstrated that neutrophil extracellular traps (NETs) formation was not recognized in neutrophils stimulated with live M. bovis. However, heat-killed M. bovis induced NETs formation. We also showed the interaction with M. bovis and bovine neutrophils regarding proinflammatory cytokine gene expression and functional expression related to NETs formation. Live and killed M. bovis induced innate immune responses in neutrophils and had the potential to induce NETs formation, but live M. bovis escaped NETs.

Mycoplasma hyorhinis infection promotes tyrosine kinase inhibitor (TKI) resistance in lung adenocarcinoma patients

PURPOSE

To explore the relationship between Mycoplasma hyorhinis infection and tyrosine kinase inhibitor (TKI) resistance in lung adenocarcinoma patients.

METHODS

Mycoplasma hyorhinis infection can be verified with the monoclonal antibody PD4, which specifically recognizes a distinct protein of M. hyorhinis. Immunohistochemistry (IHC), using PD4 to detect M. hyorhinis, was performed on paraffin-embedded lung adenocarcinoma tissues of patients who had epidermal growth factor (EGFR) mutations and had received oral TKI. The number of patients enrolled in our study was 101. Assessments following TKI treatment were performed until objective disease progression or stable disease at the cutoff date was reached. In all of the patients, the primary endpoint was investigator-assessed progression-free survival (PFS).

RESULTS

Immunohistochemistry revealed that 61 of 101 cases (60.4%) of lung adenocarcinoma were positive for M. hyorhinis, which comprised of 31 low-positive cases and 30 high-positive cases; the remaining 40 cases (39.6%) were negative. The median PFS was significantly longer in the negative group [18 months (95% CI 14.15-21.85)] than in the low-positive group [10 months (95% CI 7.70-12.30); hazard ratio (HR) 4.095, 95% CI 2.254-7.438; p < 0.001] and in the high-positive group [4 months (95% CI 2.85-5.15); HR 31.703, 95% CI 14.425-69.678; p < 0.001]. The results of the subgroup analysis were satisfactory. The PFS benefit with negative M. hyorhinis infection was consistent across subgroups.

CONCLUSIONS

In this retrospective, exploratory analysis, M. hyorhinis infection significantly reduced PFS. With increased levels of M. hyorhinis infection, the progression of the disease was more advanced, likely due to the hydrolysis of TKI by M. hyorhinis. A strong correlation was found between M. hyorhinis infection and TKI resistance in lung adenocarcinoma. This study provides potent evidence that M. hyorhinis hydrolyses TKI and will assist in the research of related mechanisms in the future.

IMPLICATIONS FOR CANCER SURVIVORS

It provides an option to improve the efficacy of TKI, including strategies to decrease M. hyorhinis infection, thereby reducing long-term distress in TKI resistance patients with EGFR mutations.

Sequence variation and immunogenicity of the Mycoplasma genitalium MgpB and MgpC adherence proteins during persistent infection of men with non-gonococcal urethritis

Mycoplasma genitalium is a sexually transmitted bacterial pathogen that infects men and women. Antigenic variation of MgpB and MgpC, the immunodominant adherence proteins of M. genitalium, is thought to contribute to immune evasion and chronic infection. We investigated the evolution of mgpB and mgpC sequences in men with non-gonococcal urethritis persistently infected with M. genitalium, including two men with anti-M. genitalium antibodies at enrollment and two that developed antibodies during follow-up. Each of the four patients was persistently infected with a different strain type and each patient produced antibodies targeting MgpB and MgpC. Amino acid sequence evolution in the variable regions of MgpB and MgpC occurred in all four patients with changes observed in single and multiple variable regions over time. Using the available crystal structure of MgpC of the G37 type strain we found that predicted conformational B cell epitopes localize predominantly to the variable region of MgpC, amino acids that changed during patient infection lie in these epitopes, and variant amino acids are in close proximity to the conserved sialic acid binding pocket. These findings support the hypothesis that sequence variation functions to avoid specific antibodies thereby contributing to persistence in the genital tract.

The Lipocalin2 Gene is Regulated in Mammary Epithelial Cells by NFκB and C/EBP In Response to Mycoplasma

Lcn2 gene expression increases in response to cell stress signals, particularly in cells involved in the innate immune response. Human Lcn2 (NGAL) is increased in the blood and tissues in response to many stressors including microbial infection and in response to LPS in myeloid and epithelial cells. Here we extend the microbial activators of Lcn2 to mycoplasma and describe studies in which the mechanism of Lcn2 gene regulation by MALP-2 and mycoplasma infection was investigated in mouse mammary epithelial cells. As for the LPS response of myeloid cells, Lcn2 expression in epithelial cells is preceded by increased TNFα, IL-6 and IκBζ expression and selective reduction of IκBζ reduces Lcn2 promoter activity. Lcn2 promoter activation remains elevated well beyond the period of exposure to MALP-2 and is persistently elevated in mycoplasma infected cells. Activation of either the human or the mouse Lcn2 promoter requires both NFκB and C/EBP for activation. Thus, Lcn2 is strongly and enduringly activated by mycoplasma components that stimulate the innate immune response with the same basic regulatory mechanism for the human and mouse genes.

Calves Infected with Virulent and Attenuated Mycoplasma bovis Strains Have Upregulated Th17 Inflammatory and Th1 Protective Responses, Respectively

Mycoplasma bovis is a critical bovine pathogen, but its pathogenesis remains poorly understood. Here, the virulent HB0801 (P1) and attenuated HB0801-P150 (P150) strains of M. bovis were used to explore the potential pathogenesis and effect of induced immunity from calves’ differential transcriptomes post infection. Nine one-month-old male calves were infected with P1, P150, or mock-infected with medium and euthanized at 60 days post-infection. Calves in P1 group exhibited other clinical signs and pathological changes compared to the other two groups. Transcriptome profiles of peripheral blood mononuclear cells revealed seven and 10 hub differentially expressed genes (DEGs) in P1 and P150 groups compared with mock-infected group, respectively. Then, P1-induced pathogenesis was predicted to be associated with enhanced Th17, and P150-induced immunity with Th1 response and expression of ubiquitination-associated enzymes. Association analysis showed that 14 and 11 DEGs were positively and negatively correlated with pathological changes, respectively. Furthermore, up-regulated expression in molecules critical to differentiation of pathogenic Th17 cells in lung and peripheral blood mononuclear cells in P1 group was validated at RNA and protein levels. The results confirmed virulent and attenuated strains might be associated with biased differentiation of pro-inflammatory pathogenic Th17 and Th1 subsets respectively.

Transcriptional Regulation of gga-miR-451 by AhR:Arnt in Mycoplasma gallisepticum (HS Strain) Infection

MicroRNAs (miRNAs) have been determined to be important regulators for pathogenic microorganism infection. However, it is largely unclear how miRNAs are triggered during pathogen infection. We previously reported that the up-regulation of gga-miR-451 negatively regulates the Mycoplasma gallisepticum (MG)-induced production of inflammatory cytokines via targeting tyrosine3-monooxygenase/tryptophan5-monooxygenase activation protein zeta (YWHAZ). The aim of this study was to investigate the mechanism regulating gga-miR-451 in MG infection in chickens. Analysis of gga-miR-451 precursor, pri-miR-451, and pre-miR-451 indicated that the regulation occurred transcriptionally. We also identified the transcriptional regulatory region of gga-miR-451 that contained consensus-binding motif for aryl hydrocarbon receptor (AhR) and aryl hydrocarbon receptor nuclear translocator (Arnt) complex, which is known as the transcription factor that regulates gene expression. Luciferase reporter assays combined with chromatin immunoprecipitation (ChIP) demonstrated that AhR:Arnt bound directly to the promoter elements of gga-miR-451, which were responsible for gga-miR-451 transcription in the context of MG infection. Furthermore, upregulation of AhR:Arnt significantly induced gga-miR-451 and inhibited YWHAZ expression, suggesting that AhR:Arnt may play an anti-inflammatory role in MG infection. This discovery suggests that induced gga-miR-451 expression is modulated by AhR:Arnt in response to MG infection.

gga-miR-451 Negatively Regulates Mycoplasma gallisepticum (HS Strain)-Induced Inflammatory Cytokine Production via Targeting YWHAZ

Mycoplasma gallisepticum (MG) is the most economically significant mycoplasma pathogen of poultry that causes chronic respiratory disease (CRD) in chickens. Although miRNAs have been identified as a major regulator effect on inflammatory response, it is largely unclear how they regulate MG-induced inflammation. The aim of this study was to investigate the functional roles of gga-miR-451 and identify downstream targets regulated by gga-miR-451 in MG infection of chicken. We found that the expression of gga-miR-451 was significantly up-regulated during MG infection of chicken embryo fibroblast cells (DF-1) and chicken embryonic lungs. Overexpression of gga-miR-451 decreased the MG-induced inflammatory cytokine production, including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6), whereas inhibition of gga-miR-451 had the opposite effect. Gene expression data combined with luciferase reporter assays demonstrated that tyrosine3-monooxygenase/tryptophan5-monooxygenase activation protein zeta (YWHAZ) was identified as a direct target of gga-miR-451 in the context of MG infection. Furthermore, upregulation of gga-miR-451 significantly inhibited the MG-infected DF-1 cells proliferation, induced cell-cycle arrest, and promoted apoptosis. Collectively, our results demonstrate that gga-miR-451 negatively regulates the MG-induced production of inflammatory cytokines via targeting YWHAZ, inhibits the cell cycle progression and cell proliferation, and promotes cell apoptosis. This study provides a better understanding of the molecular mechanisms of MG infection.

Molecular characterization of hemotropic mycoplasmas (Mycoplasma ovis and 'Candidatus Mycoplasma haemovis') in sheep and goats in China

BACKGROUND

Hemotropic mycoplasmas (hemoplasmas) are emerging zoonotic pathogens with a worldwide distribution that can cause mild to severe hemolytic anemia, icterus, ill-thrift, infertility, and poor weight gain. However, understanding of the molecular epidemiology of hemoplasmas (Mycoplasma ovis and 'Candidatus Mycoplasma haemovis') is limited in sheep and goats, and the hemoplasma strain/species/variant 'Candidatus M. haemovis' was poorly studied throughout the world and had never been detected in China until now. Thus, the aim of the present study was to determine the molecular prevalence of hemoplasmas, including M. ovis and 'Candidatus M. haemovis' in sheep and goats from seven provinces and one autonomous region of China.

METHODS

A total of 1364 blood samples were collected from sheep and goats in seven provinces and one autonomous region of China. All blood samples were tested for hemoplasmas (M. ovis and 'Candidatus M. haemovis') by nested PCR amplification based on 16S rRNA gene. Positive specimens underwent nucleotide sequencing and phylogenetic analysis.

RESULTS

Overall, 610 specimens (44.7%, 610/1364) were shown to be hemoplasmas (M. ovis and 'Candidatus M. haemovis') -positive by nested PCR amplification based on 16S rRNA gene. The prevalence in goats was 44.1% (379/860), and 45.8% (231/504) in sheep, while that in grazing small ruminants was 54.4% (396/728) and 33.6% (214/636) in house feeding small ruminants. Sequencing of the nearly complete 16S rRNA gene was successful for the 103 randomly selected positive specimens from different farms in different sampling sites of China. Among them, analysis of the 16S rRNA gene sequences identified M. ovis (n = 56) and 'Candidatus M. haemovis' (n = 47). Two (KU983740 and KU983746) of the four novel genotypes obtained in this study were closely related to M. ovis, while the other two genotypes (KU983748 and KU983749) had high identity with 'Candidatus M. haemovis'. Remarkably, the genotype (KU983740) of M. ovis in sheep and goats in this study fell in a clade with two human hemoplasmas from USA (KF313922 and GU230144) and shared 99.8%-99.9% with them.

CONCLUSIONS

In this study, 'Candidatus M. haemovis' was first detected in Chinese sheep and goats and hemoplasmas (M. ovis and 'Candidatus M. haemovis') are highly prevalent, and widely distributed in China.

Identification of differentially expressed miRNAs through high-throughput sequencing in the chicken lung in response to Mycoplasma gallisepticum HS

Mycoplasma gallisepticum (MG) infects chickens, causes chronic respiratory diseases (CRD) and severely damages the poultry industry. It has been suggested that micro-ribonucleic acids (miRNAs) are involved in microbial pathogenesis. Here, we identified miRNAs that are associated with MG infection in chicken lungs at 3 and 10days post-infection by deep sequencing. Thirty-six down-regulated and 9 up-regulated miRNAs belonging to 31 miRNA families were detected at 3days post-infection, whereas 50 down-regulated and 18 up-regulated miRNAs belonging to 41 miRNA families were found at 10days post-infection. The 45 and 68 differentially expressed miRNAs at 3 and 10days target 6280 and 7181 genes, respectively. In this study, 8 candidate novel chicken miRNAs were identified. Analyses via GO, KEGG, miRNA-GO-network, path-net and gene-net showed that these altered miRNAs might be involved in regulating the host response to MG infection by targeting genes in many pathways, such as the MAPK pathway, focal adhesion, Wnt pathway, endocytosis, Jak/STAT pathway, phosphatidylinositol pathway, adherens junctions, regulation of actin cytoskeleton among others. These analyses indicate that the MAPK pathway may be a key regulatory route. Also, the miR-8 family, miR-499 family, miR-17 family, and PIK3 family genes, as well as the MAP2K1 and RAC1 genes, might be important in MG infection. miR-20 of the miR-17 family was further confirmed by RT-qPCR. The important miRNAs, mRNAs and pathways associated with MG infection in chicken are valuable for further research. Our data provide new insights into the mechanism of these miRNAs on the regulation of host-MG interactions.

CELL CULTURES PURITY CONTROL BY METHODS OF CLINICAL DIAGNOSTICS

Cell cultures of higher organisms, especially cultures of human cells, are increasingly used in medical, pharmaceutical and scientific research. The main problem of cell cultures — non-lethal hidden contamination by mycoplasmas, viruses and outsider cell lines. As an available and reliable method for monitoring the purity of the cell cultures, we offer to use PCR kits designed and officially used in clinical diagnostics. We have tested 50 human cell lines using commercial diagnostic systems for detection of papilloma viruses, herpes viruses, adenoviruses, Mycoplasma hominis and total bacterial mass. Contamination in tested cell lines was not found. In the case of cell lines that contain integrated parts of viral genomes, the presence of the respective DNA sequences was confirmed. The proposed diagnostic systems can be effectively used to control the purity of cell lines, for qualitative detection of possible contamination, as well as for quantitative evaluations with calculation of viral load like it is practiced in clinical diagnostics.

Study of polymorphic variants of the TNF gene in pregnant women with mycoplasma infection in the Kazakh population

A molecular genetic study of DNA in 98 pregnant women with mycoplasma infection and 100 healthy pregnant women was carried out. The results of the study revealed that the presence of the homozygous mutant genotype AA increases the risk of pro-inflammatory processes in the body by 6.7 times, and the carriage of GA genotypic variants increases the risk of its occurrence by 2.6 times.

Relationship Among Chlamydia and Mycoplasma Pneumoniae Seropositivity, IKZF1 Genotype and Chronic Obstructive Pulmonary Disease in A General Japanese Population: The Nagahama Study

Chronic obstructive pulmonary disease (COPD) is a possible risk factor for cardiovascular disease. The association of COPD with the pathogenicity of infection with Chlamydia pneumoniae and Mycoplasma pneumoniae is controversial. We conducted a cross-sectional study to clarify the association between atypical pneumoniae seropositivity and COPD in a general population. We also investigated genetic polymorphisms conferring susceptibility to a pneumonia titer. The study included 9040 Japanese subjects (54 ± 13 years). COPD was defined as a ratio of forced expiratory volume in 1 second to forced vital capacity of less than 70%. Serum levels of IgA and IgG antibodies to C pneumoniae were determined using an enzyme-linked immunoassay, and M pneumoniae seropositivity was assessed by a particle agglutination test. Subjects seropositive for C pneumoniae (26.1%) had a higher prevalence of COPD (seropositive, 5.8%; seronegative, 3.1%; P < 0.001) after adjustment for age, sex, height, weight, and smoking status. The association between M pneumoniae seropositivity (20.4%) and COPD was also significant in covariate-adjusted analysis (P < 0.001). A genome-wide association analysis of the C pneumoniae IgA index identified a susceptible genotype (rs17634369) near the IKZF1 gene, and the seropositive rate of C pneumoniae significantly differed among genotypes (AA, 22.5; AG, 25.3; GG, 29.7%, P < 0.001). On multiple regression analysis, seropositivity for both C pneumoniae (odds ratio = 1.41, P = 0.004) and M pneumoniae (odds ratio = 1.60, P = 0.002) was an independent determinant for COPD, while no direct association was found with the rs17634369 genotype. Seropositivity for both C pneumoniae and M pneumoniae is an independent risk factor for COPD in the general population.

Disruption of the pdhB pyruvate dehydrogenase [corrected] gene affects colony morphology, in vitro growth and cell invasiveness of Mycoplasma agalactiae

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.

[Mycoplasma genitalium-derived lipid-associated membrane proteins negatively regulate cytokine secretion by inducing HO-1 expression in placental trophoblast cells]

OBJECTIVE

To observe the expression of heme oxygenase-1 (HO-1) in regulation of cytokines response induced by Mycoplasma genitalium-derived lipid-associated membrane proteins (LAMPs) in placental trophoblast cells.

METHODS

Placental trophoblast cells were cultured in vitro and stimulated by 0.5-5 μg/mL LAMPs for 4 to 12 hours. Expression of HO-1 mRNA and protein, and nuclear translocation of nuclear factor erythroid-2 related factor 2 (Nrf2) were detected by real-time quantitative PCR and Western blotting, respectively. The intracellular formation of reactive oxygen species (ROS) was detected by the fluorescent probe H2DCFDA. N-acetyl-cysteine (NAC) and nuclear factor erythroid-2 related factor 2 (Nrf2) siRNA were respectively used to analyze the roles of ROS and Nrf2 in mediating HO-1 expression. Finally, placental trophoblast cells were transfected with HO-1 siRNA, or preincubated by the HO-1 agonist cobalt protoporphyrin (CoPP) or its inhibitor zinc protoporphyrin (ZnPP), and LAMPs-induced secretion of TNF-α and IL-1β were detected by ELISA.

RESULTS

M. genitalium LAMPs induced the expression of HO-1 mRNA and protein, the accumulation of ROS and the nuclear translocation of Nrf2 in placental trophoblast cells. NAC treatment inhibited LAMPs-induced HO-1 expression and Nrf2 nuclear translocation, and the transfection of Nrf2 siRNA significantly abrogated HO-1 expression. Furthermore, HO-1 siRNA and ZnPP treatment increased LAMPs-induced TNF-α and IL-1β secretion, while the HO-1 agonist CoPP treatment further decreased their production.

CONCLUSION

M. genitalium LAMPs could induce placental trophoblast cells to express HO-1 through ROS/Nrf2 pathways. Up-regulation of HO-1 negatively regulates excessive production of cytokines.

Mycoplasmal upper respiratory tract disease across the range of the threatened Mojave Desert tortoise: associations with thermal regime and natural antibodies

Most research of upper respiratory tract disease (mycoplasmal URTD) in the threatened Mojave Desert tortoise (Gopherus agassizii) has worked under the hypothesis that the pathogen, Mycoplasma agassizii, has a relatively consistent and predictable effect on tortoise populations across their natural range. In contrast, we hypothesized that multiple factors influence the prevalence of disease and analyzed biological and environmental variables that vary significantly across the Mojave Desert. We used multiple regression models to analyze associations between mycoplasmal URTD and the genetic structure of 24 tortoise populations, levels of natural antibody (NAb) to M. agassizii in tortoises (one component of the innate immune system), precipitation, and colder thermal regimes. We detected a significant, positive association between mean levels of NAb and seroprevalence to M. agassizii. We hypothesized that NAbs may provide tolerance to mycoplasmal infections and that more tolerant populations may act as host reservoirs of disease. We also detected significant associations between colder winters and mycoplasmal URTD, suggesting that colder winters may depress tortoise immune resistance against M. agassizii or enhance conditions for the growth of M. agassizii.

Mycoplasma synoviae induces upregulation of apoptotic genes, secretion of nitric oxide and appearance of an apoptotic phenotype in infected chicken chondrocytes

The role of chondrocytes in the development of infectious arthritis is not well understood. Several examples of mycoplasma-induced arthritis in animals indicate that chondrocytes come into direct contact with bacteria. The objective of this study was to analyze the interaction of an arthrogenic Mycoplasma synoviae strain WVU 1853 with chicken chondrocytes. We found that M. synoviae significantly reduces chondrocyte respiration. This was accompanied by alterations in chondrocyte morphology, namely cell shrinkage and cytoplasm condensation, as well as nuclear condensation and formation of plasma membrane invaginations containing nuclear material, which appeared to cleave off the cell surface. In concordance with these apoptosis-like events in chondrocytes, transcription was increased in several pro-apoptotic genes. Twenty-four hours after infection, strong upregulation was assayed in NOS2, Mapk11, CASP8 and Casp3 genes. Twenty-four and 72 h incubation of chondrocytes with M. synoviae induced upregulation of AIFM1, NFκB1, htrA3 and BCL2. Casp3 and NOS2 remained upregulated, but upregulation ceased for Mapk11 and CASP8 genes. Increased production of nitric oxide was also confirmed in cell supernates. The data suggests that chicken chondrocytes infected with M. synoviae die by apoptosis involving production of nitric oxide, caspase 3 activation and mitochondrial inactivation. The results of this study show for the first time that mycoplasmas could cause chondrocyte apoptosis. This could contribute to tissue destruction and influence the development of arthritic conditions. Hence, the study gives new insights into the role of mycoplasma infection on chondrocyte biology and development of infectious arthritis in chickens and potentially in humans.

Contrasting epidemic histories reveal pathogen-mediated balancing selection on class II MHC diversity in a wild songbird

The extent to which pathogens maintain the extraordinary polymorphism at vertebrate Major Histocompatibility Complex (MHC) genes via balancing selection has intrigued evolutionary biologists for over half a century, but direct tests remain challenging. Here we examine whether a well-characterized epidemic of Mycoplasmal conjunctivitis resulted in balancing selection on class II MHC in a wild songbird host, the house finch (Carpodacus mexicanus). First, we confirmed the potential for pathogen-mediated balancing selection by experimentally demonstrating that house finches with intermediate to high multi-locus MHC diversity are more resistant to challenge with Mycoplasma gallisepticum. Second, we documented sequence and diversity-based signatures of pathogen-mediated balancing selection at class II MHC in exposed host populations that were absent in unexposed, control populations across an equivalent time period. Multi-locus MHC diversity significantly increased in exposed host populations following the epidemic despite initial compromised diversity levels from a recent introduction bottleneck in the exposed host range. We did not observe equivalent changes in allelic diversity or heterozygosity across eight neutral microsatellite loci, suggesting that the observations reflect selection rather than neutral demographic processes. Our results indicate that a virulent pathogen can exert sufficient balancing selection on class II MHC to rescue compromised levels of genetic variation for host resistance in a recently bottlenecked population. These results provide evidence for Haldane's long-standing hypothesis that pathogens directly contribute to the maintenance of the tremendous levels of genetic variation detected in natural populations of vertebrates.

Mycoplasma ovis in captive cervids: prevalence, molecular characterization and phylogeny

Hemotrophic mycoplasmas (hemoplasmas) are bacteria that attach to red blood cells of mammals, leading to acute and/or subclinical disease in infected animals. It has been suggested that Mycoplasma ovis, a hemoplasma that infects sheep and goats worldwide, may also infect deer. The aim of this study was to evaluate whether South American deer are infected with M. ovis. EDTA-anticoagulated blood samples from a herd of 32 captive South American deer were collected. DNA extraction of blood samples was performed followed by PCR amplification of the 16S and 23S rRNA genes, and sequencing of products. Using M. ovis PCR, 27/31 (87%) were positive, including 21/22 Mazama nana; 2/3 Mazama americana and 4/6 Blastocerus dichotomus. Sequencing of the nearly entire 16S rRNA gene of 26/27 positive samples showed 98.2-98.8% identity to M. ovis of sheep (GenBank, AF338268) and 98.6-99.4% identity to M. ovis-like of a fawn (FJ824847); the 23S rRNA gene from one of these isolates and the fawn's had 97.6% identity. The remaining isolate had just 94.9% identity to the 16S rRNA gene of M. ovis and only 89.4% identity to the 23S rRNA gene of the fawn's M. ovis. This is the first report of M. ovis in captive South American deer, revealing a high prevalence of hemoplasma infection in these animals.

[Phylogenetic analysis of the mycoplasma isolated from the Javanese macaque (M. fascicularis)]

The nucleotide sequence of the fragment of 16S-aRNA of mycoplasma was determined. The fragment was identified using the PCR method in the urogenital scrape of the Javanese macaque (M. fascicularis). The sequenced fragment of mycoplasma of M. fascicularis was compared to well-known sequences of mycoplasma of mammals. The results of our comparative and phylogenetic analyses of the sequenced DNA fragment revealed that the mycoplasma belonged to the M. primatum species and fell within the same cluster as M. hominis. The mycoplasma M. primatum was for the first time observed in the monkeys M. fascicularis. The pathogenicity of the mycoplasma species with respect to monkeys is being studied.

[Peculiarities of genotype distribution of interleukins (IL-1 and IL-10) in patients with peptic ulcer disease and their associations with persistence of Mycoplasma hyorhinis and Helicobacter pylori genotypes]

It was found for the first time in our study that there is a significant prevalence of combinations of IL-1 and IL-10 genotypes--IL-1B-511C/C, IL-1B+3954C/C, IL-1RN1/1, IL-10-1082A/A and IL-1B-511T/C, IL-1B+3954C/C, IL-1RN1/2, IL-10- 1082A/G--in the group of patients with gastric and duodenal ulcer disease and control one, respectively. The correlation between the Tox- (cagA- vacAs1-) strains of H. pylori and the combinations of genotypes IL-1B-511T/C, IL-1B +3954C/C, IL-1RN1/1, IL-10-1082G/G was shown (p <0,05). Co-infection with H. pylori and M. hyorhinis was detected in 19% of patients. The association between combinations of genotypes IL-1B-511T/T IL-1B+3954C/C, IL-1RN2/2, IL-10-1082A/G and co-infection with H. pylori and M. hyorhinis was also found (p <0,05).

Cytokine and chemokine transcription profile during Mycoplasma pulmonis infection in susceptible and resistant strains of mice: macrophage inflammatory protein 1beta (CCL4) and monocyte chemoattractant protein 2 (CCL8) and accumulation of CCR5+ Th cells

The progression of murine mycoplasma pneumonia is dependent on T cells and other immune cells. The role of cytokines in immunity are complex, and identifying the network of cytokines produced after infection of mice is essential in dissecting the key cytokine cascades involved mycoplasma disease pathogenesis. In the present study, mRNA expression of 143 different cytokines, chemokines, or receptors were evaluated in lung tissues from both susceptible (BALB/c and C3H/HeN) and resistant (C57BL/6) mice after Mycoplasma pulmonis infection. To accomplish this, membrane-based cDNA microarrays were used to monitor changes mRNA expression in lungs. There was a clear association with disease susceptibility and development of cytokine mRNA expression. In addition to proinflammatory cytokines, mRNA expression of an anti-inflammatory cytokine, interleukin-10, increased with disease severity, suggesting an attempt to moderate the severity of the inflammatory response. Furthermore, it is clear that an array of chemokines produced in susceptible mice could contribute to the recruitment and maintenance of inflammatory cells at the site of disease. In support of this, there was an increase in macrophage inflammatory protein 1beta (MIP-1beta; CCL4) and monocyte chemoattractant protein 2 (MCP-2; CCL8) mRNA levels from mycoplasma-infected mice and a corresponding accumulation of CD4+ Th cells expressing the MIP-1beta/MCP-2 receptor, CCR5, in the lungs of mice. Furthermore, MIP-1beta- and MCP-2-producing cells and CD4+ T cells were found to be in close association in pulmonary lesions. Thus, there was a significant cytokine response associated with disease pathogenesis, and these studies provide important leads and insights into ongoing cytokine- and chemokine-mediated processes in this persistent inflammatory disease.

Development of in-situ hybridization for the detection of Mycoplasma haemosuis (Eperythrozoon suis) in formalin-fixed, paraffin wax-embedded tissues from experimentally infected splenectomized pigs

Mycoplasma haemosuis DNA was detected in experimentally infected splenectomized pigs by in-situ hybridization (ISH) with a nonradioactive digoxigenin-labelled DNA probe. An 839 base pair DNA probe targeting a 16S rRNA gene was generated by the polymerase chain reaction. Eight 6-week-old pigs were inoculated intraperitoneally with 6 ml of M. haemosuis-infected pig blood and eight negative control pigs were inoculated intraperitoneally with 6 ml of M. haemosuis-free blood. Two pigs from each group were killed for examination at 3, 7, 15 and 30 days post-inoculation (dpi). Red blood cells infected with M. haemosuis were first detected by light microscopy at 3 to 7 dpi. No M. haemosuis was observed in negative control pigs. Hybridization signals were evident in blood from the infected pigs at 3 dpi. The ISH method developed in this study was useful for the detection of M. haemosuis DNA in formalin-fixed, paraffin wax-embedded tissues and may be valuable for studying the pathogenesis of M. haemosuis infection.

Specific detection and typing of Mycoplasma synoviae strains in poultry with PCR and DNA sequence analysis targeting the hemagglutinin encoding gene vlhA

Mycoplasma synoviae is a major pathogen of chickens and turkeys, causing economic losses to the poultry industry worldwide. In this study, we validated and applied polymerase chain reaction (PCR) and DNA sequence analysis on the N-terminal end of the hemagglutinin encoding gene vlhA as an alternative for the detection and initial typing of field strains of M. synoviae in commercial poultry. PCR primers were tested against isolates of M. synoviae from various sources along with other avian mycoplasma and other bacterial species. The vlhA gene-targeted PCR assay was highly specific in the identification of M. synoviae, with a detection limit of 4.7 x 10(2) color changing units/ml. DNA sequence analysis of amplified products was also conducted to validate the potential for typing M. synoviae strains using the N-terminal region of the vlhA gene. To evaluate the test, we applied the PCR assay to tracheal swabs collected from chickens challenged with M. synoviae strain K1968 and compared the results to the serologic detection. The PCR assay was also evaluated directly on tracheal samples collected from commercial layers. Overall, this vlhA gene-targeted PCR is a useful tool for detection and initial typing of M. synoviae and can be applied in the preliminary identification of M. synoviae isolates directly from clinical samples.

Mycoplasma fermentans infection promotes immortalization of human peripheral blood mononuclear cells in culture

Chronic infection or colonization by mycoplasma(s) could gradually and significantly alter many biologic properties of mammalian host cells in culture, including induction of malignant transformation. We examined effects of Mycoplasma fermentans infection on the continuing survival and immortality of human peripheral blood mononuclear cells (PBMCs) from healthy blood donors. Without specific supplemental growth factors, human PBMCs normally die rapidly, with few cells other than macrophages/monocytes surviving after 2 weeks in cultures. Only occasional Epstein-Barr virus (EBV)–positive B lymphocytes would continue to proliferate and undergo spontaneous immortalization. Our present study revealed that infection of human PBMCs in culture with the incognitus and PG18 strains of M fermentans, but surprisingly not with some other strains tested in parallel, markedly enhanced the rate of EBV-positive B lymphocytes to undergo immortalization (74% vs 17%). Compared with spontaneously immortalized PBMCs, the PBMCs immortalized in cultures infected with the mycoplasmas often had prominent karyotype changes with chromosomal loss, gain, or translocations. Furthermore, many of these immortalized B lymphocytes were found to be monoclonal in nature. The in vitro findings would be of relevance to lymphoproliferative disorders that occurred in patients with immune suppression. The mycoplasma-mediated promotional effect in cell immortalization and its potential clinical implications warrant further study.

Rat strains differ in susceptibility to maternal and fetal infection with Mycoplasma pulmonis

PROBLEM

Vaginally infected Sprague-Dawley (SD) rats are more susceptible to adverse pregnancy outcomes than Wistar (WIS) rats. We postulated that SD rats have enhanced hematogenous spread of Mycoplasma pulmonis to fetal tissues.

METHOD OF STUDY

WIS and SD dams were infected intravenously with 10(7), 10(6), and 10(5) colony-forming units of M. pulmonis at gestation day 14. Dams and six randomly selected fetuses were cultured at days 15, 16, 17, and 18 of gestation.

RESULTS

In the high-dose group, 100% of fetuses were colonized regardless of rat strain. Significantly higher numbers of M. pulmonis were isolated from placenta (low dose, P < 0.0001; medium dose, P < 0.024; high dose, P < 0.0001), amniotic fluid (low dose, P < 0.003; medium dose, P < 0.017), and fetuses (low dose, P < 0.0011) of SD rats. Spread of M. pulmonis to the amniotic fluid and fetus occurred 1 day earlier in SD rats.

CONCLUSIONS

The difference in susceptibility between the two rat strains cannot be explained by hematogenous spread alone. The relative resistance to adverse pregnancy outcomes in WIS rats may be a function of a more robust innate immune system. These rat strains may represent an animal model to address host resistance factors to intrauterine infection.

Mycoplasma gallisepticum--induced alterations in cytokine genes in chicken cells and embryos

Mycoplasma gallisepticum (MG) was used to infect the MSB-1 cells, the HD-11 cells, and chicken embryos. The RNA from these cells and the embryonic spleen cells were extracted and assayed for the expression of cytokine genes using reverse transcription-polymerase chain reaction. The results showed that MG infection suppressed the expression of the IL-8 gene in the MSB-1 cells and enhanced the expression of the IL-8 and IL-6 genes in the HD-11 cells; a slightly increased expression of macrophage inflammatory protein-1beta (MIP-1beta) in MG-infected spleen cells was noted. Because of the divergent response in cytokine expression in different cell types, more work needs to be done before a correlation between the cytokine gene expression and the pathogenesis of a disease can be made.

Presence of human mycoplasma DNA in gastric tissue samples from Korean chronic gastritis patients

We aimed to determine whether mycoplasmas are present in Korean chronic gastritis, and to understand their roles in gastric cancer tumorigenesis, because mycoplasmas resemble Helicobacter pylori in terms of ammonia production and induction of inflammatory cytokines in immune and non-immune cells. The presence and identity of mycoplasmas were assessed by semi-nested PCR and sequencing, and the results were compared with pathologic data. Fifty-six samples collected from Korean chronic gastritis patients were used for this study. Twenty-three (41.1%) were positive for mycoplasmas. Eighteen sequenced samples contained a single human mycoplasma or two mycoplasmas, which were identified as Mycoplasma faucium (13/18), M. fermentans (3/18), M. orale (1/18), M. salivarium (2/18), and M. spermatophilum (1/18). Mycoplasma-infected chronic gastritis samples showed significantly more severe neutrophil infiltration than non-infected samples (P = 0.0135). Mycoplasma profiles in the oral cavity (M. salivarium is major) and stomach were different, and the presence of significant proinflammatory responses in mycoplasma-positive patients suggests that the mycoplasmas are not simply contaminants. Further studies are required to understand whether mycoplasmas play a role in gastric tumorigenesis.

A specific PCR for the detection of Mycoplasma putrefaciens, one of the agents of the contagious agalactia syndrome of goats

Mycoplasma putrefaciens is listed as one of the etiologic agents of the contagious agalactia syndrome by the world organisation for animal health. This species has been characterized only recently, 1974, and the number of outbreaks caused by this microorganism so far is very scarce. It induces mastitis in infected goats although other symptoms such as arthritis in adults and septicaemia in kids are also frequently described. Up to now, the identification of M. putrefaciens relied on classical isolation and identification techniques which present a number of limitations. Specific primers for PCR have been designed based on sequence comparisons of the ArcB gene among the 'Mycoplasma mycoides cluster' and related species such as Mycoplasma cottewii and Mycoplasma yeatsii. Sequence alignments confirmed the taxonomic position of M. putrefaciens, which is related to the 'M. mycoides cluster' but also very close to M. yeatsii. The polymorphism observed amongst the different ArcB sequences allowed the determination of a primer pair yielding a specific amplification of a 316 bp-long DNA fragment by PCR. This PCR was validated in two different laboratories with a variety of mycoplasma strains isolated from goats. This new PCR technique will be very useful for a quicker determination of M. putrefaciens strains as well as a better understanding of the prevalence of M. putrefaciens infections.

Use of a Mycoplasma hyopneumoniae nested polymerase chain reaction test to determine the optimal sampling sites in swine

A number of polymerase chain reaction (PCR)-based diagnostic tests have been developed for Mycoplasma hyopneumoniae, including one from this research group. This report presents further development, optimization, and standardization of a nested PCR test. Detection sensitivity was 1 fg of M. hyopneumoniae chromosomal DNA (approximately 1 organism). This exceeded the sensitivity of or compared favorably with other published PCR tests. Polymerase chain reaction primers to porcine beta2-microglobulin were included as internal controls for amplifiable chromosomal DNA from porcine samples. To standardize the test, a number of samples from experimentally infected pigs, including nasal, tonsil, tracheobronchial swabs, lung tissue, bronchial alveolar lavage (BAL) fluid, and tracheobronchial brush samples, were examined by PCR. Samples obtained from BAL fluid and tracheobronchial sites were most predictive of infection, whereas nasal swabs and lung tissue were not reliable indicators of experimentally induced infection. In conclusion, the nested PCR developed for this study was found to be a highly sensitive and specific diagnostic tool for M. hyopneumoniae, but the enhanced sensitivity may be unnecessary if the proper sites are sampled.

Molecular pathogenesis of mycoplasma animal respiratory pathogens

Mycoplasmas contain the smallest genomes and are the smallest known free-living organisms, yet little is known about the molecular details of their pathogenic mechanisms. This review focuses on pathogens of production animals, but related species colonize and cause disease in humans, fish and other animals, plants and insects. The general lack of genetic tools and the inability to apply the few that are available to some mycoplasma-host systems has hindered studies of this nature. During the last decade, which was characterized by unparalleled advances in the understanding of bacterial virulence, studies of mycoplasma pathogenesis has languished behind other experimental systems. The one exception has been studies on mycoplasma antigenic variation. The explosion of studies in this area has been due primarily to the fact that they can be performed in vitro without genetic tools and with simple well developed biochemical approaches. Not withstanding that antigenic variation may play an important role in disease, there have been few studies establishing the importance of this phenomenon in vivo for a variety of reasons. The same is true for cell invasion as it has been defined in cell culture systems, which if it occurs in vivo may change the way we think about mycoplasma disease. These advances give insight to an extraordinary group of organisms that interact with their hosts in unique and intriguing ways.

Mycoplasma hyopneumoniae colonization of pigs sired by different boars

Differences in Mycoplasma hyopneumoniae colonization were evaluated in experimentally inoculated pigs sired by 3 different boars of the same genetic line. Forty-six pigs were used, including a treatment group and positive and negative control groups. The pigs were intratracheally inoculated with an M. hyopneumoniae suspension or with Friis media as a placebo. To evaluate differences in the magnitude of colonization during a 35-day period, nasal and tracheal swabs were collected weekly and tested by nested polymerase chain reaction (N-PCR). Temperature, weight and circulating antibodies were measured for 35 days. At 11 and 35 d postinoculation the pigs were necropsied and macroscopic and microscopic lesions were determined. A section of bronchus was tested by the indirect immunofluorescence test (IFAT), scanning electron microscopy (SEM) and N-PCR. The N-PCR results from the nasal and tracheal swabs showed that the pigs sired by one boar (B3) had a distinctive colonization pattern, different from that of the pigs from the other 2 boars and from the positive controls. SEM studies demonstrated that at 35 d postinoculation a higher proportion of B3 pigs had lower numbers of mycoplasmas attached to the cilia compared with B1 and B2 offspring. No significant differences were observed in temperature and weight gain among groups by ANOVA; however, with use of a 2 x 2 table, temperature differences were observed between pigs sired by boars B1 and B2 at 4 d postinoculation. No pigs seroconverted, showed gross or microscopic lesions, or had positive IFAT results. These results provide evidence of differences in patterns of colonization between pigs sired by different boars, suggesting a possible genetic effect.

Concordance between genetic relatedness and phenotypic similarities of Trichomonas vaginalis strains

BACKGROUND

Despite the medical importance of trichomoniasis, little is known about the genetic relatedness of Trichomonas vaginalis strains with similar biological characteristics. Furthermore, the distribution of endobionts such as mycoplasmas or Trichomonas vaginalis virus (TVV) in the T. vaginalis metapopulation is poorly characterised.

RESULTS

We assayed the relationship between 20 strains of T. vaginalis from 8 countries using the Random Amplified Polymorphic DNA (RAPD) analysis with 27 random primers. The genealogical tree was constructed and its bootstrap values were computed using the program FreeTree. Using the permutation tail probability tests we found that the topology of the tree reflected both the pattern of resistance to metronidazole (the major anti-trichomonal drug) (p < 0.01) and the pattern of infection of strains by mycoplasmas (p < 0.05). However, the tree did not reflect pattern of virulence, geographic origin or infection by TVV. Despite low bootstrap support for many branches, the significant clustering of strains with similar drug susceptibility suggests that the tree approaches the true genealogy of strains. The clustering of mycoplasma positive strains may be an experimental artifact, caused by shared RAPD characters which are dependent on the presence of mycoplasma DNA.

CONCLUSIONS

Our results confirmed both the suitability of the RAPD technique for genealogical studies in T. vaginalis and previous conclusions on the relatedness of metronidazol resistant strains. However, our studies indicate that testing analysed strains for the presence of endobionts and assessment of the robustness of tree topologies by bootstrap analysis seem to be obligatory steps in such analyses.

A multiplex-PCR for the diagnosis of contagious agalactia of sheep and goats

A multiplex polymerase chain reaction (m-PCR) assay was optimized for the simultaneous detection of several species of small ruminant mycoplasmas. Two sets of oligonucleotide primers specific for Mycoplasma agalactiae (Ma) and Mycoplasma "mycoides" cluster (M.m. cluster) were used in the test. The m-PCR was able to amplify a 375-bp fragment of Ma chromosomal DNA and a 257-260-bp fragment of M.m. cluster chromosomal DNA. Four reference strains (M. agalactiae, M. mycoides subsp. mycoides LC, M. capricolum subsp. capricolum, M. mycoides subsp. capri) and 56 samples (44 milk samples, two nasal swabs, six ocular swabs, three vaginal swabs and one sample of fibrinous exudate from carpal joint), from sheep and goats with clinical signs of contagious agalactia (CA), were examined. The m-PCR confirmed the identification of reference strains and allowed to identify, of the 43 positive samples examined, 35 Ma strains, 12 M. "mycoides" cluster strains; in four samples both Ma and mycoplasmas of M. "mycoides" cluster were revealed. The m-PCR was able to detect 1 pg of mycoplasma DNA. The specificity and sensitivity of the m-PCR suggest its use for the "routine" diagnosis of CA.

[Differential activity of genes of Mycoplasma pneumoniae in acute and chronic forms of experimental infection]

The complex of investigations was carried out with a view to study the mechanisms making it possible for mycoplasmas to switch off the expression of definite genes in persistence. The main method used in these investigations was the method of molecular portrayal, or RNA fingerprinting, with the use of arbitrary primers. The comparative analysis of gene expression in M. pneumoniae strains having different virulence revealed that in the avirulent strain subcultured under in vitro conditions the expression of considerable number of genes was inhibited. In the body of an experimental animal the expression of many genes, including the gene coding the synthesis of the main pathogenicity factor, adhesion protein, switched on.

[Association of TAP1/TAP2 gene polymorphism with inflammatory urogenital diseases combined with joint diseases]

AIM

To study association of TAP1/TAP2 gene polymorphism with urogenital infections combined with joint lesions.

MATERIALS AND METHODS

Of 139 patients examined 45 ones had inflammation caused by Chlamydia trachomatis (17 had joint disease), 42 had Mycoplasma hominis infection (joint lesions in 17 cases). Method of amplification was used on the basis of specific primers (ARMS).

RESULTS

Patients infected with C. trachomatis significantly more frequently had allele TAP1-02011 and TAP2-0201 (RR = 18.5, p < 0.01 and RR = 4.61, p < 0.05, respectively). Joint lesion in patients with chlamydial infection was associated with allele TAP1-02011 (RR = 11.92, p < 0.05). In mycoplasmosis association with joint lesions there is a significant link of joint syndrome with heterogeneous combination threonine/alanine in gene TAP2 position 565 (RR = 4.22, p < 0.05).

CONCLUSION

The findings can be used for predicting the joint syndrome development in patients with urogenital infection.

Randomly amplified polymorphic DNA (RAPD) analysis of Mycoplasma gallisepticum isolates from turkeys from the central valley of California

Randomly amplified polymorphic DNA (RAPD) analysis was used to investigate the molecular epidemiology of 26 Mycoplasma gallisepticum (MG) isolates obtained from turkeys located in the central valley of California. The MG isolates were recovered from 5 different companies and 13 ranches. Each company had unique MG strains. No evidence of spread of MG between companies was detected. RAPD analysis of MG isolates within a ranch during an outbreak revealed only a single strain involved in each outbreak. RAPD analysis identified an isolate from 1 ranch with a banding pattern identical to that of the 6/85 vaccine strain, which had been used on that particular ranch. Similar RAPD banding patterns of isolates from different ranches within the same company suggested horizontal spread of MG between ranches. The use of 2 primer sets in RAPD analysis was critical to prevent misinterpretation of relationships between different isolates.

Development and evaluation of a polymerase chain reaction assay using the 16S rRNA gene for detection of Eperythrozoon suis infection

The 16S ribosomal RNA (rRNA) gene of Eperythrozoon suis was amplified using gene-specific primers developed from GenBank sequence accession U88565. The gene was subsequently cloned and sequenced. Based on these sequence data, 3 sets of E. suis-specific primers were designed. These primers selectively amplified 1394, 690, and 839 base-pair (bp) fragments of the 16S rRNA gene from DNA of E. suis extracted from the blood of an experimentally infected pig during a parasitemic episode. No polymerase chain reaction (PCR) products were amplified from purified DNA of Haemobartonella felis, Mycoplasma genitalium, or Bartonella bacilliformis using 2 of these primer sets. When the primer set amplifying the 690-bp fragment was used, faint bands were observed with H. felis as the target DNA. No PCR products were amplified from DNA that had been extracted from the blood of a noninfected pig or using PCR reagents without target DNA. The detection limits for E. suis by competitive quantitative PCR were estimated to range from 57 and 800 organisms/assay. This is the first report of the utility of PCR-facilitated diagnosis and quantitation of E. suis based on the 16S rRNA gene. The PCR method developed will be useful in monitoring the progression and significance of E. suis in the disease process in the pig.

Interferon-alpha and haptoglobin in pigs selectively bred for high and low immune response and infected with Mycoplasma hyorhinis

Pigs selected for high (H) or low (L) combined antibody and cell-mediated immune response were infected with Mycoplasma hyorhinis. Following the infection, arthritis was more severe in the H pigs, while pleuritis and peritonitis were more severe in the L pigs. Since Mycoplasma infections in pigs often cause just mild signs, indicators of the inflammatory response may aid diagnosis of such infections. In addition, data about the genetic influence on inflammatory response indicators are scanty in the pig. The objectives of the study were therefore: firstly, to determine interferon-alpha (IFNalpha) and haptoglobin in M. hyorhinis infected pigs and, secondly, to investigate if the inflammatory response as determined by these indicators was influenced by genetic selection. There was no consistent increase of IFN-alpha in serum following infection. The serum haptoglobin concentration started to increase 3 days post-infection and there was no difference between the two breeding lines. Hence, M. hyorhinis infection in pigs is reflected in increased serum haptoglobin concentration, but no effect of the magnitude of the inflammatory response on this indicator by selection for high or low immune response was observed.

Complementary randomly amplified polymorphic DNA (RAPD) analysis patterns and primer sets to differentiate Mycoplasma gallisepticum strains

Randomly amplified polymorphic DNA (RAPD) analysis was used to differentiate 7 strains of Mycoplasma gallisepticum. Six commercially available primers or primer combinations were screened for their ability to differentiate vaccine and type strains. Although major and minor bands were produced with each primer, many of the primers were unsuitable for strain differentiation. The use of primer 6 and combined primers 3 and 4 resulted in complementary RAPD banding patterns for each M. gallisepticum strain. Eleven different isolates representing 7 different strains were segregated into 7 different patterns, corresponding to the 7 strains.

Roles of innate and adaptive immunity in respiratory mycoplasmosis

Current evidence suggests that host defense in respiratory mycoplasmosis is dependent on both innate and humoral immunity. To further delineate the roles of innate and adaptive immunity in antimycoplasmal defenses, we intranasally infected C3H/HeSnJ-scid/scid (C3H-SCID), C3H/HeSnJ (C3H), C57BL/6J-scid/scid (C57-SCID), and C57BL/6N (C57BL) mice with Mycoplasma pulmonis and at 14 and 21 days postinfection performed quantitative cultures of lungs and spleens, quantification of lung lesions, and histopathologic assessments of all other major organs. We found that numbers of mycoplasmas in lungs were associated with genetic background (C3H susceptible, C57BL resistant) rather than functional state of adaptive immunity, indicating that innate immunity is the main contributor to antimycoplasmal defense of the lungs. Extrapulmonary dissemination of mycoplasmas with colonization of spleens and histologic lesions in multiple organs was a common occurrence in all mice. The absence of adaptive immune responses in severe combined immunodeficient (SCID) mice resulted in increased mycoplasmal colonization of spleens and lesions in extrapulmonary sites, particularly spleens, hearts, and joints, and also reduced lung lesion severity. The transfer of anti-M. pulmonis serum to infected C3H-SCID mice prevented extrapulmonary infection and disease, while the severity of lung lesions was restored by transfer of naive spleen cells to infected C3H-SCID mice. Collectively, our results strongly support the conclusions that innate immunity provides antimycoplasmal defense of the lungs and humoral immunity has the major role in defense against systemic dissemination of mycoplasmal infection, but cellular immune responses may be important in exacerbation of mycoplasmal lung disease.

Natural resistance to Mycoplasma pulmonis infection in mice: host resistance gene(s) map to chromosome 4

Strains of mice differ greatly in resistance to infection in their lungs with virulent Mycoplasma pulmonis (MP) organisms even during the first 5 days, prior to detection of humoral or T cell mediated acquired immune responses. C57BL/6 mice are resistant, and BALB/c and C3H mice are susceptible, and one major gene, MP, not linked to the H2 major histocompatibility complex, regulates resistance. C57BL/6 x C3H (B x H) and BALB/c x C57BL/6 (C x B) recombinant inbred strain mice were infected intratracheally with the T2 strain of MP. Five days later, the recovery of organisms from tracheolung lavages and lung tissue was determined. The strain distribution pattern of resistance indicated that the MP gene maps to chromosome 4. B6.C-H18 (B6 mice congenic for the BALB/c H18 gene of chromosome 4) were much more susceptible than B6 mice, but were less susceptible than BALB/c mice, supporting the data obtained with the recombinant inbred strain mice, but suggesting that other genes may also influence resistance to infection with MP.

Detection of Mycoplasma genitalium and Chlamydia trachomatis DNAs in male patients with urethritis using the polymerase chain reaction

The use of PCR assays as a fast and reliable method is constantly improving and easing microbiological diagnosis. We used a polymerase chain reaction (PCR) assay designed to detect Mycoplasma genitalium and Chlamydia trachomatis in urethral swab samples of 56 males with urethritis and 44 asymptomatic patients as a control group. The PCR assay provides an amplification of target sequence within MgPa (M. genitalium protein attachment) gene. Results indicated that M. genitalium was present in 6 (10.7%) patients with urethritis and none in the control group. Eleven of 56 (17.8%) patients were positive for Chlamydia trachomatis when tested by an outer membrane protein primer-based PCR. The amplified DNA fragments were homogeneous as shown by restriction enzyme analysis and found to be consistent with the published sequences. The PCR assay employed was as reliable as the cultural method in detecting C. trachomatis in the urethral swabs of patients with urethritis (100% of sensitivity when compared with the cultural method) and it has been revealed as an essential method for detection of M. genitalium.

Elongated versions of Vlp surface lipoproteins protect Mycoplasma hyorhinis escape variants from growth-inhibiting host antibodies

Variation in Vlp surface proteins of Mycoplasma hyorhinis was evaluated in terms of its role in determining susceptibility of organisms to growth inhibition by host antibodies (Abs). High-frequency switching of Vlp surface lipoproteins has been studied in isogenic lineages of M. hyorhinis SK76. In these lineages, the products of three genes, vlpA, vlpB, and vlpC, are subject to phase and size variation in vitro, which occur through distinct mutator elements that independently govern the expression of each vlp gene (promoter mutations) or the size of the vlp gene product (by intragenic expansion or contraction of a 3' region containing tandem repeats). Isogenic clonal variants of M. hyorhinis SK76 expressing distinct profiles of Vlp products were assessed for their susceptibility to complement-independent growth inhibition by serum Abs of swine experimentally infected with the arthritigenic SK76 strain. Invariably, variants expressing longer versions of VlpA, VlpB, or VlpC (each expressed individually) were completely resistant to host immune serum Abs, whereas variants expressing shorter allelic versions of each Vlp were susceptible. The target of growth-inhibiting Abs was not the Vlp products, since removal of anti-Vlp Abs had no effect on the inhibitory activity of the host immune serum on susceptible variants. Escape variant populations derived by propagating susceptible variants in an immune (versus control) host serum revealed a strong selection for the long-Vlp phenotype, irrespective of the identity of the Vlp expressed. Apparent mutational pathways of acquiring the protective phenotype included mutational switches to express long vlp genes that had been transcriptionally silent or switches to elongate expressed vlp genes. These results suggest that a major function of the Vlp system is to shield the wall-less mycoplasma surface from host Abs capable of binding vital (and as-yet-unidentified) surface antigens of this organism.