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1.
Mycoplasma infection in human and its contamination in cell cultures are worldwide problems. The drugs currently available for preventing or treating mycoplasma infection suffer from low sensitivity, strong resistance and high toxicity. Our previous work showed that Mycoplasma hyorhinis (M. hyorhinis) infection was mediated by the interaction between p37 of M. hyorhinis and Annexin A2 (ANXA2) of host cells, however the translational value of this mechanism was unknown. Herein, we synthesized the N-terminal of ANXA2 polypeptide (A2PP) and found that A2PP could decrease the infection of M. hyorhinis to gastric cancer cells and block M. hyorhinis infection-induced cell migration. Furthermore, we found that A2PP could reduce M. hyorhinis contamination of passage cells. Moreover, compared with the commercial antibiotics commonly used in cell culture to prevent M. hyorhinis infection, A2PP demonstrated a more effectiveness but a low toxicity on cell growth. Thus, our study for the first time revealed A2PP’s potential for the treatment and prevention of M. hyorhinis infection.  相似文献   

2.
Summary In an extensive host range study ofM. hyorhinis mink lung cells (MvlLu, ATCC CCL 64) were found to be the cells of choice for the propagation of this mycoplasm, which otherwise is often difficult to grow in a cell-free medium. Furthermore, rapid plaque assay and plaque purification procedures were developed forM. hyorhinis. The titer ofM. hyorhinis grew to 1×107 to 1×108 pfu/ml within three d postinoculation on mink lung cells. DNA restriction enzyme analysis of the genome ofM. hyorhinis was performed. Endonucleases Bst EII and Xho I are the most suitable enzymes for cleavingM. hyorhinis DNA into distinct fragment patterns. Thus, the use of the combination mink lung cells for mycoplasma growth with subsequent restriction enzyme analysis leads to an unamibiguous detection and identification toM. hyorhinis strains even in minute amounts.  相似文献   

3.
4.
Aberrant DNA methylation is frequently observed in disease, including many cancer types, yet the underlying mechanisms remain unclear. Because germline and somatic mutations in the genes that are responsible for DNA methylation are infrequent in malignancies, additional mechanisms must be considered. Mycoplasmas spp., including Mycoplasma hyorhinis, efficiently colonize human cells and may serve as a vehicle for delivery of enzymatically active microbial proteins into the intracellular milieu. Here, we performed, for the first time, genome-wide and individual gene mapping of methylation marks generated by the M. hyorhinis CG- and GATC-specific DNA cytosine methyltransferases (MTases) in human cells. Our results demonstrated that, upon expression in human cells, MTases readily translocated to the cell nucleus. In the nucleus, MTases selectively and efficiently methylated the host genome at the DNA sequence sites free from pre-existing endogenous methylation, including those in a variety of cancer-associated genes. We also established that mycoplasma is widespread in colorectal cancers, suggesting that either the infection contributed to malignancy onset or, alternatively, that tumors provide a favorable environment for mycoplasma growth. In the human genome, ∼11% of GATC sites overlap with CGs (e.g., CGATmCG); therefore, the methylated status of these sites can be perpetuated by human DNMT1. Based on these results, we now suggest that the GATC-specific methylation represents a novel type of infection-specific epigenetic mark that originates in human cells with a previous exposure to infection. Overall, our findings unveil an entirely new panorama of interactions between the human microbiome and epigenome with a potential impact in disease etiology.  相似文献   

5.

Background

Mesenchymal stromal cells (MSC) have important immunomodulatory effects that can be exploited in the clinical setting, e.g. in patients suffering from graft-versus-host disease after allogeneic stem cell transplantation. In an experimental animal model, cultures of rat T lymphocytes were stimulated in vitro either with the mitogen Concanavalin A or with irradiated allogeneic cells in mixed lymphocyte reactions, the latter to simulate allo-immunogenic activation of transplanted T cells in vivo. This study investigated the inhibitory effects of rat bone marrow-derived MSC subsequently found to be infected with a common mycoplasma species (Mycoplasma hyorhinis) on T cell activation in vitro and experimental graft-versus-host disease in vivo.

Principal Findings

We found that M. hyorhinis infection increased the anti-proliferative effect of MSC dramatically, as measured by both radiometric and fluorimetric methods. Inhibition could not be explained solely by the well-known ability of mycoplasmas to degrade tritiated thymidine, but likely was the result of rapid dissemination of M. hyorhinis in the lymphocyte culture.

Conclusions

This study demonstrates the potent inhibitory effect exerted by M. hyorhinis in standard lymphocyte proliferation assays in vitro. MSC are efficient vectors of mycoplasma infection, emphasizing the importance of monitoring cell cultures for contamination.  相似文献   

6.
To effectively modulate the gene expression within an infected mammalian cell, the pathogen Mycobacterium tuberculosis would need to bring about epigenetic modifications at appropriate genomic loci. Working on this hypothesis, we show in this study that the mycobacterial protein Rv2966c is a 5-methylcytosine-specific DNA methyltransferase that is secreted out from the mycobacterium and gets localized to the nucleus in addition to the cytoplasm inside the host cell. Importantly, Rv2966c binds to specific DNA sequences, methylates cytosines predominantly in a non-CpG context and its methylation activity is positively influenced by phosphorylation. Interestingly, like the mammalian DNA methyltransferase, DNMT3L, Rv2966c can also interact with histone proteins. Ours is the first study that identifies a protein from a pathogenic bacteria with potential to influence host DNA methylation in a non-canonical manner providing the pathogen with a novel mechanism to alter the host epigenetic machinery. This contention is supported by repression of host genes upon M. tuberculosis infection correlated with Rv2966c binding and non-CpG methylation.  相似文献   

7.
Seven different tissue culture cells have been cultured with and without mycoplasma (M. hyorhinis) in the presence of various precursors of RNA. Total cellular RNA was isolated and analysed by electrophoresis on polyacrylamide gels. The results obtained with mycoplasma-infected cells can be summarized as follows:
1. 1. When cells are labelled with [8-3H]guanosine or [5-3H]uridine there is some incorporation into host cell 28S and 18S rRNA, but it is less than into mycoplasma 23S and 16S rRNA. [8-3H]guanosine or [5-3H]uridine are also incorporated into host cell and mycoplasma tRNA and mycoplasma 4.7S RNA, but the incorporation into host cell 5S rRNA and low molecular weight RNA components (LMW RNA) is reduced.
2. 2. [5-3H]uracil is not incorporated into host cell RNA but into mycoplasma tRNA, 4.7S RNA, a mycoplasma low molecular weight RNA component M1 and 23S and 16S rRNA.
3. 3. [3H]methyl groups are incorporated into mycoplasma tRNA, 23S and 16S rRNA, but not into host cell 28S, 18S, 5S rRNA nor into mycoplasma 4.7S RNA.
4. 4. With [32P]orthophosphate or [3H]adenosine as precursors, the labelling is primarily in the host RNA.
Mycoplasma infection influences the labelling of RNA primarily by an effect on the utilization of the exogenously added radioactive RNA precursors, since the generation time of mycoplasma infected cells is about the same as that of uninfected cells. Mycoplasma infection may completely prevent the identification of LMW RNA components.  相似文献   

8.
Mycobacterium ulcerans is the causative agent of the chronic, necrotizing skin disease Buruli ulcer. Modes of transmission and molecular mechanisms involved in the establishment of M. ulcerans infections are poorly understood. Interactions with host glycans are often crucial in bacterial pathogenesis and the 22 kDa M. ulcerans protein MUL_3720 has a putative role in host cell attachment. It has a predicted N-terminal lectin domain and a C-terminal peptidoglycan-binding domain and is highly expressed on the surface of the bacilli. Here we report the glycan-binding repertoire of whole, fixed M. ulcerans bacteria and of purified, recombinant MUL_3720. On an array comprising 368 diverse biologically relevant glycan structures, M. ulcerans cells showed binding to 64 glycan structures, representing several distinct classes of glycans, including sulfated structures. MUL_3720 bound only to glycans containing sulfated galactose and GalNAc, such as glycans known to be associated with keratins isolated from human skin. Surface plasmon resonance studies demonstrated that both whole, fixed M. ulcerans cells and MUL_3720 show high affinity interactions with both glycans and human skin keratin extracts. This MUL_3720-mediated interaction with glycans associated with human skin keratin may contribute to the pathobiology of Buruli ulcer.  相似文献   

9.
Recent epidemiologic, genetic, and molecular studies suggest infection and inflammation initiate certain cancers, including those of the prostate. The American Cancer Society, estimates that approximately 20% of all worldwide cancers are caused by infection. Mycoplasma, a genus of bacteria that lack a cell wall, are among the few prokaryotes that can grow in close relationship with mammalian cells, often without any apparent pathology, for extended periods of time. In this study, the capacity of Mycoplasma genitalium, a prevalent sexually transmitted infection, and Mycoplasma hyorhinis, a mycoplasma found at unusually high frequency among patients with AIDS, to induce a malignant phenotype in benign human prostate cells (BPH-1) was evaluated using a series of in vitro and in vivo assays. After 19 weeks of culture, infected BPH-1 cells achieved anchorage-independent growth and increased migration and invasion. Malignant transformation of infected BPH-1 cells was confirmed by the formation of xenograft tumors in athymic mice. Associated with these changes was an increase in karyotypic entropy, evident by the accumulation of chromosomal aberrations and polysomy. This is the first report describing the capacity of M. genitalium or M. hyorhinis infection to lead to the malignant transformation of benign human epithelial cells and may serve as a model to further study the relationship between prostatitis and prostatic carcinogenesis.  相似文献   

10.
The intracellular metabolism and cytostatic activity of the anticancer drug gemcitabine (2′,2′-difluoro-2′-deoxycytidine; dFdC) was severely compromised in Mycoplasma hyorhinis-infected tumor cell cultures. Pronounced deamination of dFdC to its less cytostatic metabolite 2′,2′-difluoro-2′-deoxyuridine was observed, both in cell extracts and spent culture medium (i.e. tumor cell-free but mycoplasma-containing) of mycoplasma-infected tumor cells. This indicates that the decreased antiproliferative activity of dFdC in such cells is attributed to a mycoplasma cytidine deaminase causing rapid drug catabolism. Indeed, the cytostatic activity of gemcitabine could be restored by the co-administration of tetrahydrouridine (a potent cytidine deaminase inhibitor). Additionally, mycoplasma-derived pyrimidine nucleoside phosphorylase (PyNP) activity indirectly potentiated deamination of dFdC: the natural pyrimidine nucleosides uridine, 2′-deoxyuridine and thymidine inhibited mycoplasma-associated dFdC deamination but were efficiently catabolized (removed) by mycoplasma PyNP. The markedly lower anabolism and related cytostatic activity of dFdC in mycoplasma-infected tumor cells was therefore also (partially) restored by a specific TP/PyNP inhibitor (TPI), or by exogenous thymidine. Consequently, no effect on the cytostatic activity of dFdC was observed in tumor cell cultures infected with a PyNP-deficient Mycoplasma pneumoniae strain. Because it has been reported that some commensal mycoplasma species (including M. hyorhinis) preferentially colonize tumor tissue in cancer patients, our findings suggest that the presence of mycoplasmas in the tumor microenvironment could be a limiting factor for the anticancer efficiency of dFdC-based chemotherapy. Accordingly, a significantly decreased antitumor effect of dFdC was observed in mice bearing M. hyorhinis-infected murine mammary FM3A tumors compared with uninfected tumors.  相似文献   

11.
It is now well appreciated that members of pathogenic bacterial populations exhibit heterogeneity in growth rates and metabolic activity, and it is known this can impact the ability to eliminate all members of the bacterial population during antibiotic treatment. It remains unclear which pathways promote slowed bacterial growth within host tissues, primarily because it has been difficult to identify and isolate slow growing bacteria from host tissues for downstream analyses. To overcome this limitation, we have developed a novel variant of TIMER, a slow-folding fluorescent protein, named DsRed42, to identify subsets of slowly dividing bacteria within host tissues. The original TIMER folds too slowly for fluorescence accumulation in quickly replicating bacterial species (Escherichia coli, Yersinia pseudotuberculosis), however DsRed42 accumulates red fluorescence in late stationary phase cultures of E. coli and Y. pseudotuberculosis. We show DsRed42 signal also accumulates during exposure to sources of nitric oxide (NO), suggesting DsRed42 signal detects growth-arrested bacterial cells. In a mouse model of Y. pseudotuberculosis deep tissue infection, DsRed42 signal was detected, and primarily accumulates in bacteria expressing markers of stationary phase growth. There was no significant overlap between DsRed42 signal and NO-exposed subpopulations of bacteria within host tissues, suggesting NO stress was transient, allowing bacteria to recover from this stress and resume replication. This novel DsRed42 variant represents a tool that will enable additional studies of slow-growing subpopulations of bacteria, specifically within bacterial species that quickly divide.  相似文献   

12.
Integrative and conjugative elements (ICEs) are mobile genetic elements that reside in a bacterial host chromosome and are prominent drivers of bacterial evolution. They are also powerful tools for genetic analyses and engineering. Transfer of an ICE to a new host involves many steps, including excision from the chromosome, DNA processing and replication, transfer across the envelope of the donor and recipient, processing of the DNA, and eventual integration into the chromosome of the new host (now a stable transconjugant). Interactions between an ICE and its host throughout the life cycle likely influence the efficiencies of acquisition by new hosts. Here, we investigated how different functional modules of two ICEs, Tn916 and ICEBs1, affect the transfer efficiencies into different host bacteria. We constructed hybrid elements that utilize the high-efficiency regulatory and excision modules of ICEBs1 and the conjugation genes of Tn916. These elements produced more transconjugants than Tn916, likely due to an increase in the number of cells expressing element genes and a corresponding increase in excision. We also found that several Tn916 and ICEBs1 components can substitute for one another. Using B. subtilis donors and three Enterococcus species as recipients, we found that different hybrid elements were more readily acquired by some species than others, demonstrating species-specific interactions in steps of the ICE life cycle. This work demonstrates that hybrid elements utilizing the efficient regulatory functions of ICEBs1 can be built to enable efficient transfer into and engineering of a variety of other species.  相似文献   

13.
We investigated the antimicrobial activity of a fluoroquinolone against two genetically close bacterial species belonging to the Pasteurellaceae family. Time-kill experiments were used to measure the in vitro activity of marbofloxacin against two strains of Mannheimia haemolytica and Pasteurella multocida with similar MICs. We observed that marbofloxacin was equally potent against 105 CFU/mL inocula M. haemolytica and P. multocida. However, an inoculum effect was observed with P. multocida, meaning that marbofloxacin activity was decreased against a 108 CFU/mL inoculum, whereas no inoculum effect was observed with M. haemolytica. Marbofloxacin activity was also tested in a lung infection model with immunocompromised mice intratracheally infected with 109 CFU of each bacteria. At the same dose, the clinical and bacteriological outcomes were much better for mice infected with M. haemolytica than for those infected with P. multocida. Moreover, bacteriological eradication was obtained with a lower marbofloxacin dose for mice infected with M. haemolytica. Our results suggest that the differential in vivo marbofloxacin efficacy observed with the two bacterial species of similar MIC could be explained by a differential inoculum effect. Consequently, MICs determined on 105 CFU inocula were not predictive of the differences in antibiotic efficacies against high bacterial inocula of closely related bacterial strains. These results could stimulate further investigations on bacterial species-specific antibiotic doses in a clinical setting.  相似文献   

14.
Elimination ofMycoplasma orale-I from chronically infected cell lines was achieved either by treatment with a mixture of antibiotics in a hypotonic solution, or with 10 vol % of anti -M.orale rabbit serum in tissue culture medium. The latter treatment was preferable in most cases, as it was practically harmless to the cells. Inactivation of this antiserum had no effect on its potency. The antibiotic-hypotonic treatment was rather destructive, but to a different degree for the various cell cultures. Both methods were equally useful for the treatment of a monkey kidney cell line contaminated with a mycoplasma strain related toM.hyorhinis. The available anti -M.hyorhinis rabbit serum was toxic for the monkey cells when not inactivated. The potency of the antiserum was rather low and even lower after inactivation. However, prolonged treatment successfully eliminated the mycoplasma. Pre-incubation of the inactivated anti -M.hyorhinis serum with tissue culture medium to which 10% non-inactivated calf serum had been added, favoured the elimination of the mycoplasma.During the treatment of contaminated cell cultures with single antibiotics a strain related toM.hyorhinis became resistant to chlortetracyclin.M.orale- I was found to be resistant to various single antibiotics.We are grateful to Professor Dr. A. Ch. Ruys (University of Amsterdam) and Dr. R. H. Leach (Mycoplasma Reference Laboratory, London) for helpful discussions and for identifying some of our mycoplasma strains; Dr. Leach also for kindly supplying us with his G. D. L.-strain. We thank Dr. H. Cohen and Dr. A. C. Hekker for their criticism and Mr. N. L. M. van Zwetselaar for his accurate technical assistance.  相似文献   

15.
Mycobacterium abscessus subsp. massiliense, a rapidly growing mycobacteria (RGM) that is becoming increasingly important among human infectious diseases, is virulent and pathogenic and presents intrinsic resistance to several antimicrobial drugs that might hamper their elimination. Therefore, the identification of new drugs to improve the current treatment or lower the risk of inducing resistance is urgently needed. Wasp venom primarily comprises peptides that are responsible for most of the biological activities in this poison. Here, a novel peptide Polydim-I, from Polybia dimorpha Neotropical wasp, was explored as an antimycobacterial agent. Polydim-I provoked cell wall disruption and exhibited non-cytotoxicity towards mammalian cells. Polydim-I treatment of macrophages infected with different M. abscessus subsp. massiliense strains reduced 40 to 50% of the bacterial load. Additionally, the Polydim-I treatment of highly susceptible mice intravenously infected with M. abscessus subsp. massiliense induced 0.8 to 1 log reduction of the bacterial load in the lungs, spleen, and liver. In conclusion, this is the first study to show the therapeutic potential of a peptide derived from wasp venom in treating mycobacteria infections. Polydim-I acts on the M. abscessus subsp. massiliense cell wall and reduce 40–90% of the bacterial load both in vitro and in vivo. The presented results encourage further studies on the use of Polydim-I as one of the components for M. abscessus subsp. massiliense treatment.  相似文献   

16.
17.
IL-36 cytokines are members of the IL-1 family of cytokines that stimulate dendritic cells and T cells leading to enhanced T helper 1 responses in vitro and in vivo; however, their role in host defense has not been fully addressed thus far. The objective of this study was to examine the role of IL-36R signaling in the control of mycobacterial infection, using models of systemic attenuated M. bovis BCG infection and virulent aerogenic M. tuberculosis infection. IL-36γ expression was increased in the lung of M. bovis BCG infected mice. However, IL-36R deficient mice infected with M. bovis BCG showed similar survival and control of the infection as compared to wild-type mice, although their lung pathology and CXCL1 response were transiently different. While highly susceptible TNF-α deficient mice succumbed with overwhelming M. tuberculosis infection, and IL-1RI deficient mice showed intermediate susceptibility, IL-36R-deficient mice controlled the infection, with bacterial burden, lung inflammation and pathology, similar to wild-type controls. Therefore, IL-36R signaling has only limited influence in the control of mycobacterial infection.  相似文献   

18.
The Teredinidae (shipworms) are a morphologically diverse group of marine wood-boring bivalves that are responsible each year for millions of dollars of damage to wooden structures in estuarine and marine habitats worldwide. They exist in a symbiosis with cellulolytic nitrogen-fixing bacteria that provide the host with the necessary enzymes for survival on a diet of wood cellulose. These symbiotic bacteria reside in distinct structures lining the interlamellar junctions of the gill. This study investigated the mode by which these nutritionally essential bacterial symbionts are acquired in the teredinid Bankia setacea. Through 16S ribosomal DNA (rDNA) sequencing, the symbiont residing within the B. setacea gill was phylogenetically characterized and shown to be distinct from previously described shipworm symbionts. In situ hybridization using symbiont-specific 16S rRNA-directed probes bound to bacterial ribosome targets located within the host gill coincident with the known location of the gill symbionts. These specific probes were then used as primers in a PCR-based assay which consistently detected bacterial rDNA in host gill (symbiont containing), gonad tissue, and recently spawned eggs, demonstrating the presence of symbiont cells in host ovary and offspring. These results suggest that B. setacea ensures successful inoculation of offspring through a vertical mode of symbiont transmission and thereby enables a broad distribution of larval settlement.  相似文献   

19.
This paper shows that the ~66 kDa band, previously isolated from the HepG2 cell line as an oligonucleotide (ON) plasma membrane ‘receptor’, is induced by Mycoplasma infection. Moreover, this band has been identified as the invariant membrane protein of Mycoplasma hyorhinis, p70, based on ribosomal DNA sequencing combined with ON ligand blotting after p70 immunoprecipitation by a monoclonal antibody. Whereas antibiotic treatment of infected HepG2 cells strongly decreased ON capture, as measured by a biochemical assay, conversely, deliberate infection of HeLa cells with M.hyorhinis dramatically promoted ON uptake but did not affect receptor-mediated endocytosis of transferrin. This was confirmed by confocal microscopy of infected HepG2 cells, which also showed an indistinguishable labelling pattern after exposure of living cells to fluorescent ON and after p70 immunolabelling in permeabilised fixed cells. We propose that ON binds to p70 on M.hyorhinis attached at the cell surface, after which the complex is internalised by ‘piggy-back’ endocytosis.  相似文献   

20.
In this study, we describe our results on the evaluation of the ability of different permissive mammalian cell lines to support the biological enrichment of mycoplasma species known to be bacterial contaminants of cell substrates. The study showed that this approach is able to significantly improve the efficiency of mycoplasma detection based on nucleic acid testing or biochemical technologies (e.g., MycoAlert mycoplasma detection). Of 10 different cell lines (Vero, MDBK, HEK-293, Hep-G2, CV-1, EBTr, WI-38, R9ab, MDCK, and High Five) used in the study, only MDCK cell culture was found to support the efficient growth of all the tested mycoplasmas (Mycoplasma arginini, M. bovis, M. fermentans, M. gallinaceum, M. gallisepticum, M. synoviae, M. hominis, M. hyorhinis, M. orale, M. salivarium, and Acholeplasma laidlawii) known to be most frequently associated with contamination of cell substrates and cell lines in research laboratories or manufacturing facilities. The infection of MDCK cells with serial dilutions of each mycoplasma species demonstrated that these common cell line contaminants can be detected reliably after 7-day enrichment in MDCK cell culture at contamination levels of 0.05 to 0.25 CFU/ml. The High Five insect cell line was also found to be able to support the efficient growth of most mycoplasma species tested, except for M. hyorhinis strain DBS1050. However, mycoplasma growth in insect cell culture was demonstrated to be temperature dependent, and the most efficient growth was observed when the incubation temperature was increased from 28°C to between 35 and 37°C. We believe that this type of mycoplasma enrichment is one of the most promising approaches for improving the purity and safety testing of cell substrates and other cell-derived biologics and pharmaceuticals.  相似文献   

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