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International Journal of Cancer Mar 2022Colonization of specific bacteria in the human mouth was reported to be associated with gastric cancer risk. However, previous studies were limited by retrospective...
Colonization of specific bacteria in the human mouth was reported to be associated with gastric cancer risk. However, previous studies were limited by retrospective study designs and low taxonomic resolutions. We performed a prospective case-control study nested within three cohorts to investigate the relationship between oral microbiome and gastric cancer risk. Shotgun metagenomic sequencing was employed to characterize the microbiome in prediagnostic buccal samples from 165 cases and 323 matched controls. Associations of overall microbial richness and abundance of microbial taxa, gene families and metabolic pathways with gastric cancer risk were evaluated via conditional logistic regression. Analyses were performed within each cohort, and results were combined by meta-analyses. We found that overall microbial richness was associated with decreased gastric cancer risk, with an odds ratio (OR) per standard deviation (SD) increase in Simpson's reciprocal index of 0.77 (95% confidence interval [CI] = 0.61-0.99). Nine taxa, 38 gene families and six pathways also showed associations with gastric cancer risk at P < .05. Neisseria mucosa and Prevotella pleuritidis were enriched, while Mycoplasma orale and Eubacterium yurii were depleted among cases with ORs and 95% CIs per SD increase in centered log-ratio transformed taxa abundance of 1.31 (1.03-1.67), 1.26 (1.00-1.57), 0.74 (0.59-0.94) and 0.80 (0.65-0.98), respectively. The top two gene families (P = 3.75 × 10 and 3.91 × 10 ) and pathways (P = 1.75 × 10 and 1.53 × 10 ) associated with gastric cancer were related to the decreased risk and are involved in hexitol metabolism. Our study supports the hypothesis that oral microbiota may play a role in gastric cancer etiology.
Topics: Adult; Black or African American; Aged; Asian People; Female; Gastrointestinal Microbiome; Humans; Male; Metabolic Networks and Pathways; Middle Aged; Mouth; Prospective Studies; Risk; Stomach Neoplasms; White People
PubMed: 34664266
DOI: 10.1002/ijc.33847 -
Brazilian Journal of Microbiology :... 2014Mycoplasma spp, belongs to the class Mollicutes and is capable to produce alterations in cellular cultures causing damages to the biotechnological industry. Bioproducts...
Mycoplasma spp, belongs to the class Mollicutes and is capable to produce alterations in cellular cultures causing damages to the biotechnological industry. Bioproducts generally require two essential inputs, bovine serum and cells. The study herein aims to evaluate the mycoplasma concentrations that affect the growing of BHK21 and Vero cells. The species used were: Mycoplasma orale, M. salivarium, M. arginini and M. hyorhinis, cultivated in a SP4 media. Two contamination tests were performed with BHK21 and Vero cells and one of them applied different concentrations of mycoplasma. In the first one, mycoplasma was applied at the day zero and, in the second one, the contamination was performed after the monolayer establishment. The both cellular cultures presented cytopathic effects with mycoplasma contamination, but the Vero cells suffered more damages than the BHK21 ones. It was also observed that the severity of the cytopathic effect depended on the mycoplasma specie, on the concentration and on the time of contact with the cellular culture, which evidences the importance of controlling the presence of mycoplasma in biotechnological industries.
Topics: Animals; Cell Line; Chlorocebus aethiops; Coculture Techniques; Cricetinae; Culture Media; Epithelial Cells; Mycoplasma
PubMed: 25763061
DOI: 10.1590/s1517-83822014000400048 -
PDA Journal of Pharmaceutical Science... 2018This experimental study compares cell size, zeta potential, and the ability to penetrate tailor-made size exclusion membrane filters of mycoplasma cultivated in five...
UNLABELLED
This experimental study compares cell size, zeta potential, and the ability to penetrate tailor-made size exclusion membrane filters of mycoplasma cultivated in five different cultivation media. The influence of relevant filtration process parameters, in particular transmembrane pressure and filtration temperature, on their respective retention was tested. The impact of the filtration temperature was further evaluated for the Gram-negative bacteria species , the Gram-positive bacteria species , the phage PP7, and the mycoplasma species The findings were correlated to the different mechanical properties of the particles, especially also with respect to the different bacterial cell envelopes found in those species. This study suggests that mycoplasma, surrounded by a flexible lipid bilayer, are significantly susceptible to changes in temperature, altering the stiffness of the cell envelope. Mycoplasma retention could thus be increased significantly by a decreased filtration temperature. In contrast, Gram-negative and Gram-positive bacteria species, with a cell wall containing a cross-linked peptidoglycan layer, as well as bacteriophages PP7 exhibiting a rigid protein capsid, did not show a temperature-dependent retention within the applied filtration temperatures between 2 and 35 °C. The trends of the retention of with increasing temperature and transmembrane pressure were independent of cultivation media. Data obtained with mycoplasma suggest that the trend of mycoplasma retention at different filtration temperatures is also independent of the membrane pore size and thus retention level. Media in biopharmaceutical processes are sterile-filtered to prevent them from bacterial contamination. Mycoplasma represent a relevant class of bacteria. In this publication it is shown that mycoplasma cell size depends on the media they are cultivated in. Membranes used for sterile filtration retain bacteria predominantly by size exclusion. Thus, an altered cell size can result in different retention values. Another characteristic of mycoplasma is the flexible lipid bilayer and the absence of a rigid cell wall. The lipid bilayer can undergo a phase transition from a gel to a liquid-crystal phase at a certain temperature, which makes it stiffer at lower temperatures. A higher stiffness can result in higher retention values during filtration, as the deformability of the mycoplasma cell is lower and the cell does not squeeze through the membrane pores.
ABBREVIATIONS
ALCM: culture medium; ASTM: American Society for Testing and Materials; ATCC: American Type Culture Collection; CFU/mL: colony-forming units per milliliter; DLS: Dynamic light scattering; LRV: Log reduction value; PES: Polyethersulfone; PFU/mL: Plaque-forming units per milliliter; PSD: Particle size distribution; PVP: Polyvinylpyrrolidone; SDS: Sodium dodecyl sulfate; SEM: Scanning electron microscopy; SLB: Saline lactose broth; TMP: Transmembrane pressure; TSB: Tryptic soy broth.
Topics: Acholeplasma laidlawii; Culture Media; Filtration; Mycoplasma; Sterilization; Temperature
PubMed: 29343618
DOI: 10.5731/pdajpst.2017.008102 -
Applied and Environmental Microbiology Sep 2015Nucleic acid amplification technique (NAT)-based assays (referred to here as NAT assays) are increasingly used as an alternative to culture-based approaches for the...
Nucleic acid amplification technique (NAT)-based assays (referred to here as NAT assays) are increasingly used as an alternative to culture-based approaches for the detection of mycoplasma contamination of cell cultures. Assay features, like the limit of detection or quantification, vary widely between different mycoplasma NAT assays. Biological reference materials may be useful for harmonization of mycoplasma NAT assays. An international feasibility study included lyophilized preparations of four distantly related mycoplasma species (Acholeplasma laidlawii, Mycoplasma fermentans, M. orale, M. pneumoniae) at different concentrations which were analyzed by 21 laboratories using 26 NAT assays with a qualitative, semiquantitative, or quantitative design. An M. fermentans preparation was shown to decrease the interassay variation when used as a common reference material. The preparation was remanufactured and characterized in a comparability study, and its potency (in NAT-detectable units) across different NATs was determined. The World Health Organization (WHO) Expert Committee on Biological Standardization (ECBS) established this preparation to be the "1st World Health Organization international standard for mycoplasma DNA for nucleic acid amplification technique-based assays designed for generic mycoplasma detection" (WHO Tech Rep Ser 987:42, 2014) with a potency of 200,000 IU/ml. This WHO international standard is now available as a reference preparation for characterization of NAT assays, e.g., for determination of analytic sensitivity, for calibration of quantitative assays in a common unitage, and for defining regulatory requirements in the field of mycoplasma testing.
Topics: DNA, Bacterial; Laboratories; Mycoplasma; Nucleic Acid Amplification Techniques; World Health Organization
PubMed: 26070671
DOI: 10.1128/AEM.01150-15 -
Journal of Oral Pathology & Medicine :... Feb 2015Mycoplasmas are the smallest free-living organisms; Mycoplasma salivarium and Mycoplasma orale are the most common species isolated from the oropharynx. Oral leukoplakia...
BACKGROUND
Mycoplasmas are the smallest free-living organisms; Mycoplasma salivarium and Mycoplasma orale are the most common species isolated from the oropharynx. Oral leukoplakia is the most prevalent potentially malignant disorder of the oral mucosa; its etiology has not been defined. Our previous study with DNA-binding fluorescent dye suggested the presence of mycoplasmas in the epithelial cells of leukoplakia tissue.
OBJECTIVE
Our aim was to detect M. salivarium in the epithelial cells of leukoplakia by immunohistochemistry.
DESIGN
We produced a polyclonal antibody (PAb) reactive to Mycoplasma by injecting a rabbit with M. salivarium cells (ATCC 23064) mixed with complete Freund's adjuvant and a monoclonal antibody specific to M. salivarium by injecting M. salivarium cells (ATCC 23557) mixed with complete Freund's adjuvant into the footpads of a rat. Then, we attempted to detect M. salivarium in the epithelium of leukoplakia tissues by immunohistochemistry.
RESULTS
We obtained an antimycoplasma rabbit PAb reactive to all seven Mycoplasma species used in this study. Three hybridoma clones producing monoclonal antibodies specific to M. salivarium were obtained, and an M. salivarium-specific monoclonal antibody, designated 7-6H, was established. Immunohistochemistry with these antibodies revealed M. salivarium in the epithelial cells of leukoplakia with hyperplasia and hyperkeratosis on histology. PCR and sequencing verified the presence of M. salivarium DNA in the epithelial cells of leukoplakia.
CONCLUSION
Intracellular M. salivarium was identified in the epithelial cells of leukoplakia.
Topics: Adult; Aged; Aged, 80 and over; Animals; Antibodies, Bacterial; Antibodies, Monoclonal; Antibody Specificity; Bacteriological Techniques; Chlorocebus aethiops; Epithelial Cells; Female; Fluorescent Antibody Technique; Freund's Adjuvant; Humans; Immunohistochemistry; Intracellular Space; Leukoplakia, Oral; Male; Microscopy, Immunoelectron; Middle Aged; Mouth Mucosa; Mycoplasma salivarium; Polymerase Chain Reaction; Rabbits; Rats; Vero Cells; Young Adult
PubMed: 25065471
DOI: 10.1111/jop.12215