Highlights of mycoplasma research—An historical perspective

Yinqin Qingfei granules alleviate Mycoplasma pneumoniae pneumonia via inhibiting NLRP3 inflammasome-mediated macrophage pyroptosis

Background

Mycoplasma pneumoniae pneumonia (MPP) is a prevalent respiratory infectious disease in children. Given the increasing resistance of M. pneumoniae (MP) to macrolide antibiotics, the identification of new therapeutic agents is critical. Yinqin Qingfei granules (YQQFG), a Chinese patent medicine formulated specifically for pediatric MPP, lacks a clear explanation of its mechanism.

Methods

The primary components of YQQFG were identified using LC-MS/MS. In vitro, RAW264.7 cells infected with MP underwent morphological examination via scanning electron microscopy. Drug-containing serum was prepared, and its intervention concentration was determined using the CCK-8 assay. The active components of YQQFG were molecularly docked with NLRP3 protein using Autodock Vina software. A RAW264.7 cell line overexpressing NLRP3 was created using lentivirus to pinpoint the target of YQQFG. In vivo, MPP model mice were established via nasal instillation of MP. Lung damage was assessed by lung index and H&E staining. Pyroptosis-associated protein levels in cells and lung tissue were measured by western blot, while interleukin (IL)-1β and IL-18 levels in cell supernatants and mouse serum were quantified using ELISA. Immunofluorescence double staining of lung tissue sections was conducted to assess the correlation between NLRP3 protein expression and macrophages. The expression of the community-acquired respiratory distress syndrome toxin (CARDS TX) was evaluated by qPCR.

Results

25 effective components with favorable oral bioavailability were identified in YQQFG. Both in vitro and in vivo studies demonstrated that YQQFG substantially reduced the expression of the NLRP3/Caspase-1/GSDMD pathway, decreasing the release of IL-1β and IL-18, and inhibited MP exotoxin. Molecular docking indicated strong affinity between most YQQFG components and NLRP3 protein. Lentivirus transfection and immunofluorescence double staining confirmed that YQQFG significantly suppressed NLRP3 expression in macrophages, outperforming azithromycin (AZM). The combination of YQQFG and AZM yielded the optimal therapeutic effect for MPP.

Conclusion

YQQFG mitigates inflammatory responses by suppressing NLRP3 inflammasome-mediated macrophage pyroptosis, thereby ameliorating MP-induced acute lung injury. YQQFG serves as an effective adjunct and alternative medication for pediatric MPP treatment.

Infection-nutrition feedbacks: fat supports pathogen clearance but pathogens reduce fat in a wild mammal

Though far less obvious than direct effects (clinical disease or mortality), the indirect influences of pathogens are difficult to estimate but may hold fitness consequences. Here, we disentangle the directional relationships between infection and energetic reserves, evaluating the hypotheses that energetic reserves influence infection status of the host and that infection elicits costs to energetic reserves. Using repeated measures of fat reserves and infection status in individual bighorn sheep (Ovis canadensis) in the Greater Yellowstone Ecosystem, we documented that fat influenced ability to clear pathogens (Mycoplasma ovipneumoniae) and infection with respiratory pathogens was costly to fat reserves. Costs of infection approached, and in some instances exceeded, costs of rearing offspring to independence in terms of reductions to fat reserves. Fat influenced probability of clearing pathogens, pregnancy and over-winter survival; from an energetic perspective, an animal could survive for up to 23 days on the amount of fat that was lost to high levels of infection. Cost of pathogens may amplify trade-offs between reproduction and survival. In the absence of an active outbreak, the influence of resident pathogens often is overlooked. Nevertheless, the energetic burden of pathogens likely has consequences for fitness and population dynamics, especially when food resources are insufficient.

Probiotic Lactobacillus fermentum TSF331, Lactobacillus reuteri TSR332, and Lactobacillus plantarum TSP05 improved liver function and uric acid management-A pilot study

Metabolic-associated fatty liver disease (MAFLD) is predominantly associated with metabolic disturbances representing aberrant liver function and increased uric acid (UA) levels. Growing evidences have suggested a close relationship between metabolic disturbances and the gut microbiota. A placebo-controlled, double-blinded, randomized clinical trial was therefore conducted to explore the impacts of daily supplements with various combinations of the probiotics, Lactobacillus fermentum TSF331, Lactobacillus reuteri TSR332, and Lactobacillus plantarum TSP05 with a focus on liver function and serum UA levels. Test subjects with abnormal levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and UA were recruited and randomly allocated into six groups. Eighty-two participants successfully completed the 60-day intervention without any dropouts or occurrence of adverse events. The serum AST, ALT, and UA levels were significantly reduced in all treatment groups (P < 0.05). The fecal microbiota analysis revealed the intervention led to an increase in the population of commensal bacteria and a decrease in pathobiont bacteria, especially Bilophila wadsworthia. The in vitro study indicated the probiotic treatments reduced lipid accumulation and inflammatory factor expressions in HepG2 cells, and also promoted UA excretion in Caco-2 cells. The supplementation of multi-strain probiotics (TSF331, TSR332, and TSP05) together can improve liver function and UA management and may have good potential in treating asymptomatic MAFLD. Trial registration. The trial was registered in the US Library of Medicine (clinicaltrials.gov) with the number NCT06183801 on December 28, 2023.

Coral microbiomes are structured by environmental gradients in deep waters

BACKGROUND

Coral-associated microbiomes vary greatly between colonies and localities with functional consequences on the host. However, the full extent of variability across the ranges of most coral species remains unknown, especially for corals living in deep waters which span greater ranges. Here, we characterized the microbiomes of four octocoral species from mesophotic and bathyal deep-sea habitats in the northern Gulf of Mexico, Muricea pendula, Swiftia exserta, Callogorgia delta, and Paramuricea biscaya, using 16S rRNA gene metabarcoding. We sampled extensively across their ranges to test for microbiome differentiation between and within species, examining the influence of environmental factors that vary with depth (53-2224 m) and geographic location (over 680 m) as well as the host coral's genotype using RAD-sequencing.

RESULTS

Coral microbiomes were often dominated by amplicon sequence variants whose abundances varied across their hosts' ranges, including symbiotic taxa: corallicolids, Endozoicomonas, members of the Mollicutes, and the BD1-7 clade. Coral species, depth, and geographic location significantly affected diversity, microbial community composition, and the relative abundance of individual microbes. Depth was the strongest environmental factor determining microbiome structure within species, which influenced the abundance of most dominant symbiotic taxa. Differences in host genotype, bottom temperature, and surface primary productivity could explain a significant part of the microbiome variation associated with depth and geographic location.

CONCLUSIONS

Altogether, this work demonstrates that the microbiomes of corals in deep waters vary substantially across their ranges in accordance with depth and other environmental conditions. It reveals that the influence of depth on the ecology of mesophotic and deep-sea corals extends to its effects on their microbiomes which may have functional consequences. This work also identifies the distributions of microbes including potential parasites which can be used to inform restoration plans in response to the Deepwater Horizon oil spill.

Pathogenic avian mycoplasmas show phenotypic differences in their biofilm forming ability compared to non-pathogenic species in vitro

Mycoplasmas are known as the minimalist microorganisms in the microbes' world. Their minimalist nature makes them highly sensitive to the environmental conditions and limits their ability to survive for extended periods outside their animal host. Nevertheless, there are documented instances of mycoplasma transmission over significant distances and this phenomenon may be linked to relatively unexplored abilities of mycoplasmas, such as their capacity to synthesize biofilm-the predominant mode of bacterial growth in nature. The authors decided to establish a method aimed at inducing the clustering of mycoplasma planktonic cells within a biofilm in vitro and subsequently assess the capacity of certain avian mycoplasmas to synthesize a biofilm. A total of 299 avian mycoplasma isolates were included in the study, encompassing both pathogenic (Mycoplasma gallisepticum, M. synoviae, M. meleagridis, M. iowae) and non-pathogenic species (M. gallinaceum, M. gallinarum, M. iners and M. pullorum). The authors successfully demonstrated the feasibility of inducing avian mycoplasmas to synthetize in vitro a biofilm, which can be visually quantified. The only species that did not produce any biofilm was M. iowae. In general, the pathogenic mycoplasmas produced greater quantities of biofilm compared to the non-pathogenic ones. Furthermore, it was observed that the ability to produce biofilm appeared to vary, both qualitatively and quantitatively, not only among different species but also among isolates of a single species. Future studies will be necessary to determine whether biofilm production plays a pivotal epidemiological role for the pathogenic avian mycoplasmas.

The lack of the influence of various species of Mycoplasma spp. on canine semen quality

Mycoplasmas colonize fish, reptiles, birds and mammals, being commensals or causing diseases, sometimes severe in ruminants, swine, poultry, or wildlife animals. So far, 15 species of canine Mycoplasma spp. have been described. Conflicting results have been presented regarding the pathogenicity of Mycoplasma spp. Although many virulence factors of these bacteria have been described, they still require attention. The main aim of our study was to evaluate the presence of known canine Mycoplasmas in the male reproductive tract of clinically healthy dogs. The second aim was to check if Mycoplasma spp. cause any abnormalities in semen quality that could have further consequences and to propose the schemes for managing the carriers. 83.3% of examined dogs were Mycoplasma spp. -positive dogs, and most of them were the carriers of more than one species. Six dogs had azoospermic ejaculates. The total spermatozoa numbers were similar in Mycoplasma -positive and negative groups. Motility was slightly higher in Mycoplasma spp.-negative group, but the difference was not statistically significant. There was no significant difference in semen characteristics between the carriers and Mycoplasma spp.-negative dogs. Neither the individual species nor the number of species strains had a significant effect on sperm morphological parameters as well as viability. Semen quality parameters are not correlated with the species found on the prepuce. Over 70% Mycoplasma spp.- positive dogs have more than one species of this bacteria. Despite finding mycoplasmas in azoospermic dogs, we suggest that they were not the cause of infertility. Mycoplasma spp. could be a part of normal microbiota in canine prepuce in individuals without any clinical signs.

A diverse microbial community and common core microbiota associated with the gonad of female Parascaris spp

The microbiome plays an important role in health, where changes in microbiota composition can have significant downstream effects within the host, and host-microbiota relationships can be exploited to affect health outcomes. Parasitic helminths affect animals globally, but an exploration of their microbiota has been limited, despite the development of anti-Wolbachia drugs to help control infections with some filarial nematodes. The equine ascarids, Parascaris spp., are considered the most pathogenic nematodes affecting juvenile horses and are also the only ascarid parasite to have developed widespread anthelmintic resistance. The aim of this study was to characterize the microbiota of this helminth, focusing on the female gonad, determine a core microbiota for this organ, identify bacterial species, and show bacterial localization to the female gonad via in situ hybridization (ISH). A total of 22 gonads were isolated from female Parascaris spp. collected from three foals, and 9 female parasites were formalin-fixed and paraffin-embedded for ISH. Next-generation sequencing was performed using V3-V4 primers as well as the Swift Amplicon™ 16S+ ITS Panel. Overall, ten genera were identified as members of the Parascaris spp. female gonad and twelve bacterial species were identified. The most prevalent genus was Mycoplasma, followed by Reyranella, and there were no differences in alpha diversity between parasites from different horses. Specific eubacteria staining was identified in both the intestine and within the gonad using ISH. Overall, this study provided in-depth information regarding the female Parascaris spp. microbiota and was the first to identify the core microbiota within a specific parasite organ.

Fecal Microbiome Analysis Distinguishes Bacterial Taxa Biomarkers Associated with Red Fillet Color in Rainbow Trout

The characteristic reddish-pink fillet color of rainbow trout is an important marketing trait. The gastrointestinal microbiome is vital for host health, immunity, and nutrient balance. Host genetics play a crucial role in determining the gut microbiome, and the host-microbiome interaction impacts the host's phenotypic expression. We hypothesized that fecal microbiota could be used to predict fillet color in rainbow trout. Fish were fed Astaxanthin-supplemented feed for six months, after which 16s rDNA sequencing was used to investigate the fecal microbiome composition in rainbow trout families with reddish-pink fillet coloration (red fillet group, average saturation index = 26.50 ± 2.86) compared to families with pale white fillet color (white fillet group, average saturation index = 21.21 ± 3.53). The linear discriminant analysis effect size (LEFse) tool was used to identify bacterial biomarkers associated with fillet color. The alpha diversity measure shows no difference in the red and white fillet groups. Beta diversity principal component analysis showed clustering of the samples along the white versus red fillet group. The red fillet group has enrichment (LDA score > 1.5) of taxa Leuconostoc lactis, Corynebacterium variabile, Jeotgalicoccus halotolerans, and Leucobacter chromiireducens. In contrast, the white fillet group has an enriched presence of mycoplasma, Lachnoclostridium, and Oceanobacillus indicireducens. The enriched bacterial taxa in the red fillet group have probiotic functions and can generate carotenoid pigments. Bacteria taxa enriched in the white fillet group are either commensal, parasitic, or capable of reducing indigo dye. The study identified specific bacterial biomarkers differentially abundant in fish families of divergent fillet color that could be used in genetic selection to improve feed carotenoid retention and reddish-pink fillet color. This work extends our understanding of carotenoid metabolism in rainbow trout through the interaction between gut microbiota and fillet color.

Effects and Eradication of Mycoplasma Contamination on Patient-derived Colorectal Cancer Organoid Cultures

Patient-derived organoids are a useful platform for identification and testing of novel precision oncology approaches. Patient-derived organoids are generated by direct culture of patient samples. However, prior to development into patient-derived organoids, these samples are often processed for clinical use, opening the potential for contamination by Mycoplasma and other microbes. While most microbes can be detected by visual inspection, Mycoplasma can go undetected and have substantial impacts on assay results. Given the increased use of patient-derived organoids, there is a growing need for a standardized protocol to detect and remove Mycoplasma from organoid models. In the current study, we report a procedure for Mycoplasma removal by passaging organoids through mice as patient-derived organoid xenografts. In vivo passage of patient-derived organoids followed by re-establishment was 100% effective at decontaminating colorectal patient-derived organoids (n = 9), based on testing with the Sigma LookOut Mycoplasma PCR Detection Kit. This process can serve as a method to re-establish contaminated patient-derived organoids, which represent precious models to study patient-specific genomic features and treatment responses.

SIGNIFICANCE

Organoids are valuable models of cancer. Mycoplasma contamination can alter organoid drug sensitivity, so there is a need for a standardized protocol to detect and remove Mycoplasma from organoids. We report a simple procedure for removing Mycoplasma from organoids via in vivo passaging through mice followed by re-establishment of organoids.

Detection of bacterial and protozoan pathogens in individual bats and their ectoparasites using high-throughput microfluidic real-time PCR

Among the most studied mammals in terms of their role in the spread of various pathogens with possible zoonotic effects are bats. These are animals with a very complex lifestyle, diet, and behavior. They are able to fly long distances, thus maintaining and spreading the pathogens they may be carrying. These pathogens also include vector-borne parasites and bacteria that can be spread by ectoparasites such as ticks and bat flies. In the present study, high-throughput screening was performed and we detected three bacterial pathogens: Bartonella spp., Neoehrlichia mikurensis and Mycoplasma spp., and a protozoan parasite: Theileria spp. in paired samples from bats (blood and ectoparasites). In the samples from the bat-arthropod pairs, we were able to detect Bartonella spp. and Mycoplasma spp. which also showed a high phylogenetic diversity, demonstrating the importance of these mammals and the arthropods associated with them in maintaining the spread of pathogens. Previous studies have also reported the presence of these pathogens, with one exception, Neoehrlichia mikurensis, for which phylogenetic analysis revealed less genetic divergence. High-throughput screening can detect more bacteria and parasites at once, reduce screening costs, and improve knowledge of bats as reservoirs of vector-borne pathogens. IMPORTANCE The increasing number of zoonotic pathogens is evident through extensive studies and expanded animal research. Bats, known for their role as reservoirs for various viruses, continue to be significant. However, new findings highlight the emergence of Bartonella spp., such as the human-infecting B. mayotimonensis from bats. Other pathogens like N. mikurensis, Mycoplasma spp., and Theileria spp. found in bat blood and ectoparasites raise concerns, as their impact remains uncertain. These discoveries underscore the urgency for heightened vigilance and proactive measures to understand and monitor zoonotic pathogens. By deepening our knowledge and collaboration, we can mitigate these risks, safeguarding human and animal well-being.

Assessing spatial distribution, genetic variants, and virulence of pathogen Mycoplasma agassizii in threatened Mojave desert tortoises

Mojave desert tortoises (Gopherus agassizii), a threatened species under the US Endangered Species Act, are long-lived reptiles that experience a chronic respiratory disease. The virulence of primary etiologic agent, Mycoplasma agassizii, remains poorly understood, but it exhibits temporal and geographic variability in causing disease outbreaks in host tortoises. Multiple attempts to culture and characterize the diversity of M. agassizii have had minimal success, even though this opportunistic pathogen chronically persists in nearly every population of Mojave desert tortoises. The current geographic range and the molecular mechanisms of virulence of the type-strain, PS6T, are unknown, and the bacterium is thought to have low-to-moderate virulence. We designed a quantitative polymerase chain reaction (qPCR) targeting three putative virulence genes annotated on the PS6T genome as exo-α-sialidases, enzymes which facilitate growth in many bacterial pathogens. We tested 140 M. agassizii-positive DNA samples collected from 2010 to 2012 across the range of Mojave desert tortoises. We found evidence of multiple-strain infections within hosts. We also found the prevalence of these sialidase-encoding genes to be highest in tortoise populations surrounding southern Nevada, the area from which PS6T was originally isolated. We found a general pattern of loss or reduced presence of sialidase among strains, even within a single host. However, in samples that were positive for any of the putative sialidase genes, one particular gene (528), was positively associated with bacterial loads of M. agassizii and may act as a growth factor for the bacterium. Our results suggest three evolutionary patterns: (1) high levels of variation, possibly due to neutral changes and chronic persistence, (2) a trade-off between moderate virulence and transmission, and (3) selection against virulence in environmental conditions known to be physiologically stressful to the host. Our approach of quantifying genetic variation via qPCR represents a useful model of studying host-pathogen dynamics.

Motility Assays of Mycoplasma mobile Under Light Microscopy

Mycoplasma mobile forms a membrane protrusion at a pole as an organelle. M. mobile cells bind to solid surfaces and glide in the direction of the protrusion. In gliding motility, M. mobile cells catch, pull and release sialylated oligosaccharides on host cells. The observation of Mycoplasma species under light microscopy is useful for the analysis of adhesion ability and the motility mechanism.

Purification and Structural Analysis of the Gliding Motility Machinery in Mycoplasma mobile

Isolating functional units from large insoluble protein complexes are a complex but valuable approach for quantitative and structural analysis. Mycoplasma mobile, a gliding bacterium, contains a large insoluble protein complex called gliding machinery. The machinery contains several chain structures formed by motors that are evolutionarily related to the F₁-ATPase. Recently, we developed a method to purify functional motors and their chain structures using Triton X-100 and a high salt concentration buffer and resolved their structures using electron microscopy. In this chapter, we describe the processes of purification and structural analysis of functional motors for the gliding of M. mobile using negative-staining electron microscopy.

Reconstitution of a minimal motility system based on Spiroplasma swimming by two bacterial actins in a synthetic minimal bacterium

Motility is one of the most important features of life, but its evolutionary origin remains unknown. In this study, we focused on Spiroplasma, commensal, or parasitic bacteria. They swim by switching the helicity of a ribbon-like cytoskeleton that comprises six proteins, each of which evolved from a nucleosidase and bacterial actin called MreB. We expressed these proteins in a synthetic, nonmotile minimal bacterium, JCVI-syn3B, whose reduced genome was computer-designed and chemically synthesized. The synthetic bacterium exhibited swimming motility with features characteristic of Spiroplasma swimming. Moreover, combinations of Spiroplasma MreB4-MreB5 and MreB1-MreB5 produced a helical cell shape and swimming. These results suggest that the swimming originated from the differentiation and coupling of bacterial actins, and we obtained a minimal system for motility of the synthetic bacterium.

The gut microbiome of wild American marten in the Upper Peninsula of Michigan

Carnivores are ecologically important and sensitive to habitat loss and anthropogenic disruption. Here we measured trophic level and gut bacterial composition as proxies of carnivore ecological status across the Upper Peninsula, Michigan, for wild American marten (Martes americana; hereafter marten). In contrast to studies that have focused on omnivorous and herbivorous species, we find that marten, like other carnivore species without a cecum, are dominated by Firmicutes (52.35%) and Proteobacteria (45.31%) but lack Bacteroidetes. Additionally, a majority of the 12 major bacterial genera (occurring at ≥1%) are known hydrogen producers, suggesting these taxa may contribute to host energy requirements through fermentative production of acetate. Our study suggests that live trapping and harvest methods yield similar marten gut microbiome data. In addition, preserving undisturbed forest likely impacts marten ecology by measurably increasing marten trophic level and altering the gut microbiome. Our study underscores the utility of the gut microbiome as a tool to monitor the ecological status of wild carnivore populations.

Host genetic determinants drive compartment-specific assembly of tea plant microbiomes

Diverse host factors drive microbial variation in plant-associated environments, whereas their genetic mechanisms remain largely unexplored. To address this, we coupled the analyses of plant genetics and microbiomes in this study. Using 100 tea plant (Camellia sinensis) cultivars, the microbiomes of rhizosphere, root endosphere and phyllosphere showed clear compartment-specific assembly, whereas the subpopulation differentiation of tea cultivars exhibited small effects on microbial variation in each compartment. Through microbiome genome-wide association studies, we examined the interactions between tea genetic loci and microbial variation. Notably, genes related to the cell wall and carbon catabolism were heavily linked to root endosphere microbial composition, whereas genes related to the metabolism of metal ions and small organic molecules were overrepresented in association with rhizosphere microbial composition. Moreover, a set of tea genetic variants, including the cytoskeleton-related formin homology interacting protein 1 gene, were strongly associated with the β-diversity of phyllosphere microbiomes, implying their interactions with the overall structure of microbial communities. Our results create a catalogue of tea genetic determinants interacting with microbiomes and reveal the compartment-specific microbiome assembly driven by host genetics.

The first Mycoplasma ovipneumoniae recovered from a sheep with respiratory disease in Brazil - draft genome and genomic analysis

Mycoplasma ovipneumoniae is an important etiological agent of sheep respiratory disease worldwide. Here, we describe the first isolation and draft genome sequence of M. ovipneumoniae strain USP-BR2017 retrieved from tracheobronchial lavage of a sheep showing clinical signs of respiratory disease in the Rio de Janeiro State, Brazil. The culture of tracheobronchial lavage resulted in glucose-fermenting fried egg colonies, which were identified as M. ovipneumoniae by polymerase chain reaction. The genome was sequenced using the Illumina NextSeq 2000 and de novo assembled using SPAdes. The genome of the sequenced organism presented an approximate size of 1,122,253 bp. The annotation revealed 773 coding DNA sequences (CDSs), 806 genes, three rRNAs, and 30 tRNAs. Data analysis revealed M. ovipneumoniae strain USP-BR2017 contains a few virulence genes, including the hemolysing C gene (hlyC). In addition, strain USP-BR2017 showed high identity over the 16S rRNA gene with other sheep isolates from China and United States. This first description of M. ovipneumoniae in diseased Brazilian sheep demonstrates the importance of continuous surveillance and diagnostics of pathogens causing respiratory disease in sheep in Brazil.

Comparative Evaluation of the Performance of Sterile Filters for Bioburden Protection and Final Fill in Biopharmaceutical Processes

Sterile filtration processes are widely used in the production of biotherapeutics for microorganism removal and product sterility. Sterile filtration processes can be applied to buffer preparation and cell culture media preparation in biotherapeutics processes, and to final sterilization or final filling in downstream processes. Owing to their broad range of applications in bioprocessing, various 0.2/0.22 μm sterile filters with different polymer materials (i.e., hydrophilic PVDF and PES) and nominal pore sizes are commercially available. The objective of this study was to evaluate two different commercial sterile filters in terms of filtration performance in various sterile filtration processes of biopharmaceutical production. The results demonstrate the importance of choosing the appropriate filter considering the process type and target removal/transport product to ensure efficient sterile filtration in the production of biotherapeutics.

Impacts of Mycoplasma agalactiae restriction-modification systems on pan-epigenome dynamics and genome plasticity

DNA methylations play an important role in the biology of bacteria. Often associated with restriction modification (RM) systems, they are important drivers of bacterial evolution interfering in horizontal gene transfer events by providing a defence against foreign DNA invasion or by favouring genetic transfer through production of recombinogenic DNA ends. Little is known regarding the methylome of the Mycoplasma genus, which encompasses several pathogenic species with small genomes. Here, genome-wide detection of DNA methylations was conducted using single molecule real-time (SMRT) and bisulphite sequencing in several strains of Mycoplasma agalactiae, an important ruminant pathogen and a model organism. Combined with whole-genome analysis, this allowed the identification of 19 methylated motifs associated with three orphan methyltransferases (MTases) and eight RM systems. All systems had a homolog in at least one phylogenetically distinct Mycoplasma spp. Our study also revealed that several superimposed genetic events may participate in the M. agalactiae dynamic epigenomic landscape. These included (i) DNA shuffling and frameshift mutations that affect the MTase and restriction endonuclease content of a clonal population and (ii) gene duplication, erosion, and horizontal transfer that modulate MTase and RM repertoires of the species. Some of these systems were experimentally shown to play a major role in mycoplasma conjugative, horizontal DNA transfer. While the versatility of DNA methylation may contribute to regulating essential biological functions at cell and population levels, RM systems may be key in mycoplasma genome evolution and adaptation by controlling horizontal gene transfers.

Characterization and Evaluation of a Novel Conserved Membrane Antigen P35 of Mycoplasma synoviae

Mycoplasma synoviae (MS) is a major avian pathogen that causes respiratory damage, infectious synovitis, and arthritis in chickens and causes serious economic losses to the global poultry industry. Despite its significance, knowledge on pathogenicity and pathogenic mechanism of MS is lacking, especially regarding its antigens. Bioinformatic analysis showed that the known MS proteins are only the tip of the iceberg among many MS membrane proteins. In this study, we identified and expressed a novel MS membrane protein P35. Sequence similarity showed that P35 was conservative and commonly existed among MS strains. Membrane protein extraction and immunofluorescence assay confirmed that P35 was distributed on the surface of MS. The production of specific antibodies after immunization with recombinant protein rP35 suggested its immunogenicity. The antigenicity of P35 was evaluated from two aspects by using polyantiserum against MS and rP35. Furthermore, in assays to identify the immune peptides of P35, all successfully expressed truncated segments could react with positive polyantiserum of MS, suggesting that P35 had more than one immune peptide. In conclusion, our study successfully identified P35 as a conservative antigen of MS, which may act as a potential candidate for the future development of a vaccine against MS.

Evaluation of Nanopore Sequencing as a Diagnostic Tool for the Rapid Identification of Mycoplasma bovis from Individual and Pooled Respiratory Tract Samples

Rapid identification of Mycoplasma bovis infections in cattle is a key factor to guide antimicrobial therapy and biosecurity measures. Recently, Nanopore sequencing became an affordable diagnostic tool for both clinically relevant viruses and bacteria, but the diagnostic accuracy for M. bovis identification is undocumented. Therefore, in this study Nanopore sequencing was compared to rapid identification of M. bovis with matrix-assisted laser desorption ionization-time of flight mass spectrometry (RIMM) and a triplex real-time PCR assay in a Bayesian latent class model (BLCM) for M. bovis in bronchoalveolar lavage fluid (BALf) samples obtained from calves. In practice, pooling of samples is often used to save money, but the influence on diagnostic accuracy has not been described for M. bovis. Therefore, a convenience sample of 17 pooled samples containing 5 individual BALf samples per farm was analyzed as well. The results for the pooled samples were compared with those for the individual samples to determine sensitivity and specificity. The BLCM showed good sensitivity (77.3% [95% credible interval, 57.8 to 92.8%]) and high specificity (97.4% [91.5 to 99.7%]) for Nanopore sequencing, compared to RIMM (sensitivity, 93.0% [76.8 to 99.5%]; specificity, 91.3% [82.5 to 97.0%]) and real-time PCR (sensitivity, 94.6% [89.7 to 97.7%]; specificity, 86.0% [76.1 to 93.6%]). Sensitivity and specificity of pooled analysis for M. bovis were 85.7% (95% confidence interval, 59.8 to 111.6%) and 90.0% (71.4 to 108.6%%), respectively, for Nanopore sequencing and 100% (100% to 100%) and 88.9% (68.4 to 109.4%) for RIMM. In conclusion, Nanopore sequencing is a rapid, reliable tool for the identification of M. bovis. To reduce costs and increase the chance of M. bovis identification, pooling of 5 samples for Nanopore sequencing and RIMM is possible.

Force and Stepwise Movements of Gliding Motility in Human Pathogenic Bacterium Mycoplasma pneumoniae

Mycoplasma pneumoniae, a human pathogenic bacterium, binds to sialylated oligosaccharides and glides on host cell surfaces via a unique mechanism. Gliding motility is essential for initiating the infectious process. In the present study, we measured the stall force of an M. pneumoniae cell carrying a bead that was manipulated using optical tweezers on two strains. The stall forces of M129 and FH strains were averaged to be 23.7 and 19.7 pN, respectively, much weaker than those of other bacterial surface motilities. The binding activity and gliding speed of the M129 strain on sialylated oligosaccharides were eight and two times higher than those of the FH strain, respectively, showing that binding activity is not linked to gliding force. Gliding speed decreased when cell binding was reduced by addition of free sialylated oligosaccharides, indicating the existence of a drag force during gliding. We detected stepwise movements, likely caused by a single leg under 0.2-0.3 mM free sialylated oligosaccharides. A step size of 14-19 nm showed that 25-35 propulsion steps per second are required to achieve the usual gliding speed. The step size was reduced to less than half with the load applied using optical tweezers, showing that a 2.5 pN force from a cell is exerted on a leg. The work performed in this step was 16-30% of the free energy of the hydrolysis of ATP molecules, suggesting that this step is linked to the elementary process of M. pneumoniae gliding. We discuss a model to explain the gliding mechanism, based on the information currently available.

Integrating the Human and Animal Sides of Mycoplasmas Resistance to Antimicrobials

Mycoplasma infections are frequent in humans, as well as in a broad range of animals. However, antimicrobial treatment options are limited, partly due to the lack of a cell wall in these peculiar bacteria. Both veterinary and human medicines are facing increasing resistance prevalence for the most commonly used drugs, despite different usage practices. To date, very few reviews have integrated knowledge on resistance to antimicrobials in humans and animals, the latest dating back to 2014. To fill this gap, we examined, in parallel, antimicrobial usage, resistance mechanisms and either phenotype or genotype-based methods for antimicrobial susceptibility testing, as well as epidemiology of resistance of the most clinically relevant human and animal mycoplasma species. This review unveiled common features and differences that need to be taken into consideration in a "One Health" perspective. Lastly, two examples of critical cases of multiple drug resistance are highlighted, namely, the human M. genitalium and the animal M. bovis species, both of which can lead to the threat of untreatable infections.

Chained Structure of Dimeric F1-like ATPase in Mycoplasma mobile Gliding Machinery

Mycoplasma mobile, a fish pathogen, exhibits gliding motility using ATP hydrolysis on solid surfaces, including animal cells. The gliding machinery can be divided into surface and internal structures. The internal structure of the motor is composed of 28 so-called “chains” that are each composed of 17 repeating protein units called “particles.” These proteins include homologs of the catalytic α and β subunits of F₁-ATPase. In this study, we isolated the particles and determined their structures using negative-staining electron microscopy and high-speed atomic force microscopy. The isolated particles were composed of five proteins, MMOB1660 (α-subunit homolog), -1670 (β-subunit homolog), -1630, -1620, and -4530, and showed ATP hydrolyzing activity. The two-dimensional (2D) structure, with dimensions of 35 and 26 nm, showed a dimer of hexameric ring approximately 12 nm in diameter, resembling F₁-ATPase catalytic (αβ)₃. We isolated the F₁-like ATPase unit, which is composed of MMOB1660, -1670, and -1630. Furthermore, we isolated the chain and analyzed the three-dimensional (3D) structure, showing that dimers of mushroom-like structures resembling F₁-ATPase were connected and aligned along the dimer axis at 31-nm intervals. An atomic model of F₁-ATPase catalytic (αβ)₃ from Bacillus PS3 was successfully fitted to each hexameric ring of the mushroom-like structure. These results suggest that the motor for M. mobile gliding shares an evolutionary origin with F₁-ATPase. Based on the obtained structure, we propose possible force transmission processes in the gliding mechanism.

Multi-epitope-Based Vaccine Designed by Targeting Cytoadherence Proteins of Mycoplasma gallisepticum

Mycoplasma gallisepticum causes chronic respiratory disease in chickens leading to large economic losses in the poultry industry, and the impacts remain to be a great challenge for a longer period. Among the other approaches, a vaccine targeting the adhesion proteins of M. gallisepticum would be a promising candidate in controlling the infection. Thus, the present study is aimed to design a multi-epitope vaccine candidate using cytoadhesion proteins of M. gallisepticum through an advanced immunoinformatics approach. As a result, the multi-epitope vaccine was constructed, which comprised potential T-cell and B-cell binding epitopes with appropriate adjuvants. The designed multi-epitope vaccine represented high antigenicity with viable physiochemical properties. The prospective three-dimensional structure of the epitope was predicted, refined, and validated. The molecular docking analysis of multi-epitope vaccine candidates with the chicken Toll-like receptor-5 predicted effective binding. Furthermore, codon optimization and in silico cloning ensured high expression. Thus, the present finding indicates that the engineered multi-epitope vaccine is structurally stable and can induce a strong immune response. Furthermore, the multi-epitope vaccine is suggested to be a suitable vaccine candidate for the M. gallisepticum infection due to its effective binding capacity and precise specificity.

Detecting Mollicutes by PCR in goats in southwestern Bahia, Brazil

Brazil has a herd of over 9 million goats, and the northeast of Brazil is home to over 93% of this herd. Caprine mycoplasmosis are widely disseminated worldwide, being highly contagious with high rates of morbidity and mortality, causing considerable economic loss to goat herders. In addition, there has been a lack of research using molecular testing to monitor the health and detect Mollicutes in this herd in Brazil. Therefore, the aim of this study is to associate animal management with the presence of the caprine origin Mollicutes in goats, in the southwest region of the state of Bahia, Brazil. A cross-sectional study was conducted on twelve farms, and statistical analyses were performed to identify associations between the presence of Mollicutes and the management of goats. Molecular testing identified Mollicutes class, Mycoplasma agalactiae (Ma) and M. conjunctivae (Mc), in the samples analyzed. Statistical associations were observed between animals from intensive livestock facilities and the presence of Mollicutes in nasal samples and dairy ranch animals and the presence of Mollicutes in ocular samples and animals from extensive ranching sites and positive results of Mollicutes in genital samples. We conclude that mycoplasmas are present in goat herds in the southwestern region of Bahia, which supports the need for more focused studies of mycoplasmas throughout the country. Our research also demonstrated the presence of two important opportunistic bacteria, Mc and Ma, and, to the best of our knowledge, this is the first time that M. conjunctivae was detected in Brazilian goats by molecular testing.

Mycoplasma affects baseline gene expression and the response to glucocorticoids in vocal fold fibroblasts

Introduction. In vitro experimentation is intentionally contrived to isolate specific phenomena in the context of profound biological complexity. Mycoplasmas in the upper airway likely contribute to this complexity and play a largely unknown role in both health and disease. Similarly, the presence and role of mycoplasma in in vitro investigation are largely unknown.Hypothesis. We hypothesize mycoplasma in human vocal fold fibroblasts (VFF) will affect both basal gene-expression patterns as well as the cell response to exogenous stimuli.Aim. We sought to determine mycoplasma presence across vocal fold fibroblast cultures, basal transcriptional changes as a function of mycoplasma, and responsiveness to exogenous glucocorticoids in mycoplasma-positive and -negative VFF.Methodology. PCR-based mycoplasma detection was performed in an immortalized human VFF line as well as rat and rabbit primary VFF cultures and extracted rat laryngeal tissue. RNA sequencing was performed in mycoplasma-positive and -negative human cells at baseline and in response to dexamethasone.Results. Mycoplasma was identified in the human cell line as well as primary culture from rabbits. Mycoplasma was not detected in tissue or primary culture from rat vocal folds. Basal mRNA expression in human VFF differed significantly following mycoplasma treatment. In addition, differential responses to dexamethasone were observed across multiple pathways as a function of mycoplasma presence in these cells. Pathways including apoptosis, DNA damage repair, and G1 to S cell cycle signalling were significantly enriched in mycoplasma-positive cells.Conclusion. Variability of mycoplasma presence across culture conditions and differential responses to exogenous stimuli as a function of mycoplasma presence are potentially problematic for the translation of in vitro experimentation in the upper aerodigestive tract. It remains unclear if these findings represent contamination or the baseline state of this specialized tissue.

A Review of Ureaplasma diversum: A Representative of the Mollicute Class Associated With Reproductive and Respiratory Disorders in Cattle

The Mollicutes class encompasses wall-less microbes with a reduced genome. They may infect plants, insects, humans, and animals including those on farms and in livestock. Ureaplasma diversum is a mollicute associated with decreased reproduction mainly in the conception rate in cattle, as well as weight loss and decreased quality in milk production. Therefore, U. diversum infection contributes to important economic losses, mainly in large cattle-producing countries such as the United States, China, Brazil, and India. The characteristics of Mollicutes, virulence, and pathogenic variations make it difficult to control their infections. Genomic analysis, prevalence studies, and immunomodulation assays help better understand the pathogenesis of bovine ureaplasma. Here we present the main features of transmission, virulence, immune response, and pathogenesis of U. diversum in bovines.

Synthetic biology as a technoscience: The case of minimal genomes and essential genes

This article examines how minimal genome research mobilizes philosophical concepts such as minimality and essentiality. Following a historical approach the article aims to uncover what function this terminology plays and which problems are raised by them. Specifically, four historical moments are examined, linked to the work of Harold J. Morowitz, Mitsuhiro Itaya, Eugene Koonin and Arcady Mushegian, and J. Craig Venter. What this survey shows is a historical shift away from historical questions about life or descriptive questions about specific organisms towards questions that explore biological possibilities: what are possible forms of minimal genomes, regardless of whether they exist in nature? Moreover, it highlights a fundamental ambiguity at work in minimal genome research between a universality claim and a standardization claim: does a minimal genome refer to the minimal gene set for any organism whatsoever? Or does it refer rather to a gene set that will provide stable, robust and predictable behaviour, suited for biotechnological applications? Two diagnoses are proposed for this ambiguity: a philosophical diagnosis of how minimal genome research either misunderstands the ontology of biological entities or philosophically misarticulates scientific practice. Secondly, a historical diagnosis that suggests that this ambiguity is part of a broader shift towards technoscience.

Antimicrobial drug resistance mechanisms among Mollicutes

Representatives of the Mollicutes class are the smallest, wall-less bacteria capable of independent reproduction. They are widespread in nature, most are commensals, and some are pathogens of humans, animals and plants. They are also the main contaminants of cell cultures and vaccine preparations. Despite limited biosynthetic capabilities, they are highly adaptable and capable of surviving under various stress and extreme conditions, including antimicrobial selective pressure. This review describes current understanding of antibiotic resistance (ABR) mechanisms in Mollicutes. Protective mechanisms in these bacteria include point mutations, which may include non-target genes, and unique gene exchange mechanisms, contributing to transfer of ABR genes. Better understanding of the mechanisms of emergence and dissemination of ABR in Mollicutes is crucial to control these hypermutable bacteria and prevent the occurrence of highly ABR strains.

Flow-Cytometric Method for Viability Analysis of Mycoplasma gallisepticum and Other Cell-Culture-Contaminant Mollicutes

Mycoplasma is the smallest self-replicating bacteria, figuring as common contaminant of eukaryotic cell cultures. Production inputs and operator's manipulation seem to be the main sources of such contamination. Many analytical approaches have been applied for mycoplasma detection in cell cultures and also in biological products. However, unless they were validated, only indicator cell culture and bacteriological culture are considered as compendial methods for quality control of biological products. Nano-flow cytometry has been pointed out as an alternative technique for addressing prokaryotic and eukaryotic cell viability being a substantial tool for reference material production. In this study, a viability-flow-cytometry assay was standardized for M. gallisepticum and then applied to other cell-culture-contaminant mycoplasmas. For this, M. galliseticum's growth rate was observed and different treatments were evaluated to establish low viability cultures (cell death-induced control). Distinct viability markers and their ideal concentrations (titration) were appraised. Ethanol treatment showed to be the best death-inducing control. CFDA and TOPRO markers revealed to be the best choice for detecting live and dead mycoplasma frequencies, respectively. The standardized methodology was applied to Mycoplasma arginini, M. hyorhinis, M. orale, Spiroplasma citri and Acholeplasma laidlawii. Significant statistical difference was observed in the percentage of viable cells in comparison to ethanol treatment for A. laidlawii in CFDA and in both markers for M. gallisepticum, M. hyorhinis and S. citri. In summary, we standardized a flow cytometry assay for assessing M. gallisepticum - and potentially other species - viability and ultimately applied for reference material production improving the quality control of biological products.

Multilocus sequence typing characterizes diversity of Ureaplasma diversum strains, and intra-species variability induces different immune response profiles

Background

Ureaplasma diversum is a pathogen found in the genital tract of cattle and associated with genital disorders such as infertility, placentitis, abortion, birth of weak calves, low sperm motility, seminal vesiculitis and epididymitis. There are few studies evaluating the genetic diversity of U. diversum strains and their influence on the immune response in cattle. Therefore, to better understand genetic relationships of the pathogenicity of U. diversum, a multilocus sequence typing (MLST) scheme was performed to characterize the ATCC 49782 strain and another 40 isolates recovered from different Brazilian states.

Results

Primers were designed for housekeeping genes ftsH, polC, rpL22, rpoB, valS and ureA and for virulence genes, phospholipase D (pld), triacylglycerol lipase (tgl), hemolysin (hlyA), MIB-MIP system (mib,mip), MBA (mba), VsA (VsA) and ribose transporter (tABC). PCRs were performed and the targeted gene products were purified and sequenced. Sequence types (STs), and clonal complexes (CCs) were assigned and the phylogenetic relationship was also evaluated. Thus, a total of 19 STs and 4 CCs were studied. Following the molecular analysis, six isolates of U. diversum were selected, inoculated into bovine monocyte/macrophage culture and evaluated for gene expression of the cytokines TNF-α, IL-1, IL-6, IL-10 and IL-17. Differences were detected in the induction of cytokines, especially between isolates 198 and BA78, promoted inflammatory and anti-inflammatory profiles, respectively, and they also differed in virulence factors.

Conclusion

It was observed that intra-species variability between isolates of U. diversum can induce variations of virulent determinants and, consequently, modulate the expression of the triggered immune response.

In vitro evaluation of various antimicrobials against field mycoplasma gallisepticum and mycoplasma synoviae isolates in Egypt

Among many avian mycoplasmas, Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS) are recognized as the main etiological agents of respiratory diseases and infectious synovitis in chickens and turkeys causing tremendous economic losses worldwide. Therefore, proper treatment is promoted for the control of these diseases. This study was the first in Egypt to evaluate the in vitro efficacy of various antimicrobials against field MG and MS isolates recovered from chicken and turkey flocks using both conventional broth microdilution and quantitative real-time polymerase chain reaction assays. Totally, 47 mycoplasma isolates were recovered from 160 collected tracheal samples (29.4%). Of these, 44 MG (27.5%) and 3 MS (1.9%) were identified using conventional and molecular assays. The in vitro susceptibilities of 4 representative mycoplasma field isolates (3 MG and one MS) to 8 antibiotics and 4 essential oils were investigated. The tested isolates showed various susceptibilities to tested antimicrobials. Toldin CRD, followed by clove, cumin, and cinnamon oils were effective against both MG and MS clinical isolates with minimum inhibitory concentration (MIC) values ranging from 0.49 to 15.63 µg/mL. Similarly, tylvalosin was the most active antibiotic against MG and MS isolates with the lowest MIC values (0.015 to 0.03 µg/mL). DNA loads of both MG mgc2 and MS vlhA genes were markedly decreased upon treatment with majority of the tested antimicrobials confirming their effectiveness as was also evaluated by conventional MIC results. In conclusion, Toldin CRD and tylvalosin were found to be the most effective antimicrobials in this study. This finding highlights the importance of using these antimicrobials in controlling mycoplasma infections in chickens and turkeys.

Effects of Mycoplasmas on the Host Cell Signaling Pathways

Mycoplasmas are the smallest free-living organisms. Reduced sizes of their genomes put constraints on the ability of these bacteria to live autonomously and make them highly dependent on the nutrients produced by host cells. Importantly, at the organism level, mycoplasmal infections may cause pathological changes to the host, including cancer and severe immunological reactions. At the molecular level, mycoplasmas often activate the NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) inflammatory response and concomitantly inhibit the p53-mediated response, which normally triggers the cell cycle and apoptosis. Thus, mycoplasmal infections may be considered as cancer-associated factors. At the same time, mycoplasmas through their membrane lipoproteins (LAMPs) along with lipoprotein derivatives (lipopeptide MALP-2, macrophage-activating lipopeptide-2) are able to modulate anti-inflammatory responses via nuclear translocation and activation of Nrf2 (the nuclear factor-E2-related anti-inflammatory transcription factor 2). Thus, interactions between mycoplasmas and host cells are multifaceted and depend on the cellular context. In this review, we summarize the current information on the role of mycoplasmas in affecting the host’s intracellular signaling mediated by the interactions between transcriptional factors p53, Nrf2, and NF-κB. A better understanding of the mechanisms underlying pathologic processes associated with reprogramming eukaryotic cells that arise during the mycoplasma-host cell interaction should facilitate the development of new therapeutic approaches to treat oncogenic and inflammatory processes.

Refined Mechanism of Mycoplasma mobile Gliding Based on Structure, ATPase Activity, and Sialic Acid Binding of Machinery

Mycoplasma mobile, a fish pathogen, glides on solid surfaces by repeated catch, pull, and release of sialylated oligosaccharides by a unique mechanism based on ATP energy. The gliding machinery is composed of huge surface proteins and an internal "jellyfish"-like structure. Here, we elucidated the detailed three-dimensional structures of the machinery by electron cryotomography. The internal "tentacle"-like structure hydrolyzed ATP, which was consistent with the fact that the paralogs of the α- and β-subunits of F₁-ATPase are at the tentacle structure. The electron microscopy suggested conformational changes of the tentacle structure depending on the presence of ATP analogs. The gliding machinery was isolated and showed that the binding activity to sialylated oligosaccharide was higher in the presence of ADP than in the presence of ATP. Based on these results, we proposed a model to explain the mechanism of M. mobile gliding.IMPORTANCE The genus Mycoplasma is made up of the smallest parasitic and sometimes commensal bacteria; Mycoplasma pneumoniae, which causes human "walking pneumonia," is representative. More than ten Mycoplasma species glide on host tissues by novel mechanisms, always in the direction of the distal side of the machinery. Mycoplasma mobile, the fastest species in the genus, catches, pulls, and releases sialylated oligosaccharides (SOs), the carbohydrate molecules also targeted by influenza viruses, by means of a specific receptor and using ATP hydrolysis for energy. Here, the architecture of the gliding machinery was visualized three dimensionally by electron cryotomography (ECT), and changes in the structure and binding activity coupled to ATP hydrolysis were discovered. Based on the results, a refined mechanism was proposed for this unique motility.

Loop-Mediated Isothermal Amplification (LAMP) for Detection of Ureaplasma diversum from Cervico-vaginal Swab of Buffaloes

The main plan of the current study was to develop a rapid, robust, and field-applicable loop-mediated isothermal amplification (LAMP) assay for the detection of Ureaplasma diversum. A strain-specific 16S rRNA gene of Ureaplasma diversum was used for detection which was cloned, sequenced, and characterized earlier. LAMP results were visualized within 90 min with the naked eye. Cervico-vaginal swabs of 50 buffaloes were randomly collected from Livestock Research Center of NDRI as per the Institute Animal ethics guidelines. Out of 50 cervico-vaginal swab samples collected randomly, 34 were found positive with LAMP while 16 samples were negative. Conventional PCR results showed the same result. Therefore, the accuracy of the developed LAMP was about 100%. The developed LAMP assay can also be used to screen the animals for Ureaplasma diversum infection in cervico-vaginal swab. However, further study is needed to assess sensitivity and accuracy towards their detection and their relationship in disease diagnosis.

Microcolonies: a novel morphological form of pathogenic Mycoplasma spp

Introduction. The Mollicutes class unites cell wall lacking bacteria many of which are membrane parasites and opportunistic bacteria.Aim. This study describes a novel morphological form found in the five species belonging to the bacterial class Mollicutes, and referred to as microcolonies (MCs).Methodology. MCs were obtained as described below and characterized with bacteriological and immunological methods, and microscopy.Results. In contrast to typical colonies (TCs), MCs are characterized by tiny propeller-shaped colonies formed by rod-like cells tightly packed in parallel rows. These colonies were observed within routinely cultivated cultures of type strains 7-12 days post-plating. Rod-like cells were visualized using a scanning electron microscope within TCs with a 'fried-egg-like' appearance. MCs were not observed to revert to TCs. MCs were resistant to antibiotics and other treatments effective against TCs. Pure MC cultures were generated in vitro by treatment of Mycoplasma cultures with hyperimmune serum, antibiotics or argon non-thermal plasma. MCs of Mycoplasma hominis strain H-34 were characterized in detail to confirm that they belonged to that species. MCs tested positive via PCR with M. hominis-specific primers, direct fluorescence and epifluorescence tests, and Western blotting with the camel-derived nanobody aMh-FcG2a, which is specific to the MH3620 transporter protein. Meanwhile, MCs behaved differently in standard bacteriological tests. Pure MC cultures were also isolated directly from clinical samples of the serum, synovial liquid and urine of patients within flammatory urogenital tract diseases, asthma or arthritis. In total, 79 independent MC cultures were isolated from clinical samples including M. hominis (n=70), Mycoplasma pneumoniae (n=2), Mycoplasma fermentans (n=2) and Mycoplasma spp. (n=5).Conclusion. MCs play an unknown role in infection pathology and display prominent antibiotic resistance, making them a challenge for the future studies on Mollicutes.

Mycoplasma Chromosomal Transfer: A Distributive, Conjugative Process Creating an Infinite Variety of Mosaic Genomes

The capacity of Mycoplasmas to engage in horizontal gene transfers has recently been highlighted. Despite their small genome, some of these wall-less bacteria are able to exchange multiple, large portions of their chromosome via a conjugative mechanism that does not conform to canonical Hfr/oriT models. To understand the exact features underlying mycoplasma chromosomal transfer (MCT), extensive genomic analyses were performed at the nucleotide level, using individual mating progenies derived from our model organism, Mycoplasma agalactiae. Genome reconstruction showed that MCT resulted in the distributive transfer of multiple chromosomal DNA fragments and generated progenies composed of a variety of mosaic genomes, each being unique. Analyses of macro- and micro-events resulting from MCT revealed that the vast majority of the acquired fragments were unrelated and co-transferred independently from the selection marker, these resulted in up to 17% of the genome being exchanged. Housekeeping and accessory genes were equally affected by MCT, with up to 35 CDSs being gained or lost. This efficient HGT process also created a number of chimeric genes and genetic micro-variations that may impact gene regulation and/or expression. Our study unraveled the tremendous plasticity of M. agalactiae genome and point toward MCT as a major player in diversification and adaptation to changing environments, offering a significant advantage to this minimal pathogen.

Identification of novel protein domain for sialyloligosaccharide binding essential to Mycoplasma mobile gliding

Sialic acids, terminal structures of sialylated glycoconjugates, are widely distributed in animal tissues and are often involved in intercellular recognitions, including some bacteria and viruses. Mycoplasma mobile, a fish pathogenic bacterium, binds to sialyloligosaccharide (SO) through adhesin Gli349 and glides on host cell surfaces. The amino acid sequence of Gli349 shows no similarity to known SO-binding proteins. In the present study, we predicted the binding part of Gli349, produced it in Escherichia coli and proved its binding activity to SOs of fetuin using atomic force microscopy. Binding was detected with a frequency of 10.3% under retraction speed of 400 nm/s and was shown to be specific for SO, as binding events were competitively inhibited by the addition of free 3'-sialyllactose. The histogram of the unbinding forces showed 24 pN and additional peaks. These results suggested that the distal end of Gli349 constitutes a novel sialoadhesin domain and is directly involved in the gliding mechanism of M. mobile.

Antimicrobial resistance in mollicutes: known and newly emerging mechanisms

This review is devoted to the mechanisms of antibiotic resistance in mollicutes (class Bacilli, subclass Mollicutes), the smallest self-replicating bacteria, that can cause diseases in plants, animals and humans, and also contaminate cell cultures and vaccine preparations. Research in this area has been mainly based on the ubiquitous mollicute and the main contaminant of cell cultures, Acholeplasma laidlawii. The omics technologies applied to this and other bacteria have yielded a complex picture of responses to antimicrobials, including their removal from the cell, the acquisition of antibiotic resistance genes and mutations that potentially allow global reprogramming of many cellular processes. This review provides a brief summary of well-known resistance mechanisms that have been demonstrated in several mollicutes species and, in more detail, novel mechanisms revealed in A. laidlawii, including the least explored vesicle-mediated transfer of short RNAs with a regulatory potency. We hope that this review highlights new avenues for further studies on antimicrobial resistance in these bacteria for both a basic science and an application perspective of infection control and management in clinical and research/production settings.

Behaviors and Energy Source of Mycoplasma gallisepticum Gliding

Mycoplasma gallisepticum, an avian-pathogenic bacterium, glides on host tissue surfaces by using a common motility system with Mycoplasma pneumoniae In the present study, we observed and analyzed the gliding behaviors of M. gallisepticum in detail by using optical microscopes. M. gallisepticum glided at a speed of 0.27 ± 0.09 μm/s with directional changes relative to the cell axis of 0.6 degree ± 44.6 degrees/5 s without the rolling of the cell body. To examine the effects of viscosity on gliding, we analyzed the gliding behaviors under viscous environments. The gliding speed was constant in various concentrations of methylcellulose but was affected by Ficoll. To investigate the relationship between binding and gliding, we analyzed the inhibitory effects of sialyllactose on binding and gliding. The binding and gliding speed sigmoidally decreased with sialyllactose concentration, indicating the cooperative binding of the cell. To determine the direct energy source of gliding, we used a membrane-permeabilized ghost model. We permeabilized M. gallisepticum cells with Triton X-100 or Triton X-100 containing ATP and analyzed the gliding of permeabilized cells. The cells permeabilized with Triton X-100 did not show gliding; in contrast, the cells permeabilized with Triton X-100 containing ATP showed gliding at a speed of 0.014 ± 0.007 μm/s. These results indicate that the direct energy source for the gliding motility of M. gallisepticum is ATP.IMPORTANCE Mycoplasmas, the smallest bacteria, are parasitic and occasionally commensal. Mycoplasma gallisepticum is related to human-pathogenic mycoplasmas-Mycoplasma pneumoniae and Mycoplasma genitalium-which cause so-called "walking pneumonia" and nongonococcal urethritis, respectively. These mycoplasmas trap sialylated oligosaccharides, which are common targets among influenza viruses, on host trachea or urinary tract surfaces and glide to enlarge the infected areas. Interestingly, this gliding motility is not related to other bacterial motilities or eukaryotic motilities. Here, we quantitatively analyze cell behaviors in gliding and clarify the direct energy source. The results provide clues for elucidating this unique motility mechanism.

Cophylogenetic analysis suggests cospeciation between the Scorpion Mycoplasma Clade symbionts and their hosts

Scorpions are predator arachnids of ancient origin and worldwide distribution. Two scorpion species, Vaejovis smithi and Centruroides limpidus, were found to harbor two different Mollicutes phylotypes: a Scorpion Mycoplasma Clade (SMC) and Scorpion Group 1 (SG1). Here we investigated, using a targeted gene sequencing strategy, whether these Mollicutes were present in 23 scorpion morphospecies belonging to the Vaejovidae, Carboctonidae, Euscorpiidae, Diplocentridae, and Buthidae families. Our results revealed that SMC is found in a species-specific association with Vaejovidae and Buthidae, whereas SG1 is uniquely found in Vaejovidae. SMC and SG1 co-occur only in Vaejovis smithi where 43% of the individuals host both phylotypes. A phylogenetic analysis of Mollicutes 16S rRNA showed that SMC and SG1 constitute well-delineated phylotypes. Additionally, we found that SMC and scorpion phylogenies are significantly congruent, supporting the observation that a cospeciation process may have occurred. This study highlights the phylogenetic diversity of the scorpion associated Mollicutes through different species revealing a possible cospeciation pattern.

A novel approach for the identification and phylogenetic delineation of human Mycoplasma species and strains using genomic segment sequence analysis

Human Mycoplasma are opportunistic, facultative pathogens that are site-specific in their colonization of mucosal surfaces. They are responsible for significant annual morbidity in humans by causing acute illnesses and chronic auto-inflammatory diseases via modulation of the host's immune system. Accurate and reliable identification of Mycoplasma species and their strains are thus of upmost importance. This study, analysed for the first time, the effectiveness of a short (50 kb) genome fragment (termed as R-segment), which includes the complete rRNA operon and the flanking region up to 50 kb, as a single phylogenetic marker for assessing the molecular taxonomy and determining the identity of human Mycoplasma species and their strains. The R-segments of human mycoplasmas were shown to have inherent genetic properties [average nucleotide identity (ANI), codon bias index (CBI), genome-to-genome distances (GGD) and % G + C] similar to their whole genome counterparts. Based on the results of our R segment analysis, a species of human Mycoplasma can simply be defined as a group of strains that share R-segments with ANIs ≥97%. Additionally, R-segments offered superiority to 16S rRNA gene sequences and multilocus sequences for the delineation of the human Mycoplasma species and their strains. The overall comparative genomic results suggest that R-segment analysis can be considered as a promising cost-effective tool for the epidemiological surveillance and differentiation of the closely related species and/or strains of human mycoplasmas.

Detection of Mycoplasma Contamination of Cell Culture by A Loop-Mediated Isothermal Amplification Method

Objective

Mycoplasmas are major contaminants of cell culture and affect in vitro biological and diagnostic tests. Mycoplasma detection is conducted using culture and molecular methods. These methods vary in terms of accuracy, reliably and sensitivity. Loop-mediated isothermal amplification (LAMP) is used to amplify target DNA in a highly specific and rapid manner. This study aimed to develop a LAMP method for rapid detection of Mycoplasma in culture samples.

Materials and Methods

In this descriptive laboratory study, for LAMP detection of Mycoplasma contaminations in cell culture, we used primers specifically designed for targeting the 16S rRNA conserved gene of Mycoplasma spp. For a positive control structure, 16S rRNA amplified based on PCR, was cloned in a plasmid vector and sequenced. The assay specificity was evaluated using Mycoplasma genomic DNA and a panel containing genomes of gram-positive and gram-negative organisms.

Results

In this study, the method developed for detection of Mycoplasma contamination of cell cultures was a rapid, sensitive and cost-effective LAMP approach. The results demonstrated that this method benefits from high specificity (100%) for amplification of Mycoplasma strains and high speed (multiplication within 60 minutes), while it does not require expensive laboratory equipment compared to those needed for polymerase chain reaction (PCR)-based detection.

Conclusion

Our study is the first report about application of LAMP assay based on 16S rRNA gene for detection of Mycoplasma strains; this technique could be considered a useful tool for rapid detection of contamination of cell culture.

Development of a highly sensitive PCR/DNA chip method to detect mycoplasmas in a veterinary modified live vaccine

Mycoplasmas are potential contaminants that introduce undesirable changes in mammalian cell cultures. They frequently contaminate cell substrates and other starting materials used for manufacturing cell-derived biologics, such as vaccines and pharmaceutical products. Mycoplasma purity testing of live vaccines, active ingredients, raw material, and seed lots is required during vaccine production. Previously, testing using a time-consuming, costly 28-day culture assay, which lacks sensitivity for species that do not grow in culture, was required in the European Pharmacopoeia (Ph. Eur). But now nucleic acid amplification techniques (NATs) can be used. NATs provide rapid results and are sensitive. We evaluated the sensitivity and specificity of a commercially-available NAT to detect individual mycoplasma DNA in a veterinary modified live vaccine using five reference strains recommended by the Ph. Eur. Our results showed that this NAT-based method can be used to detect mycoplasma in spiked live vaccine, without interference from the vaccine components, with a limit of detection of 10 CFU/mL, as required by the Ph. Eur. Its specificity was demonstrated since no mycoplasmas were detected in non-spiked vaccine. This method is undergoing validation as a replacement for the conventional culture method in the production of veterinary live vaccines.

Detailed Analyses of Stall Force Generation in Mycoplasma mobile Gliding

Mycoplasma mobile is a bacterium that uses a unique mechanism to glide on solid surfaces at a velocity of up to 4.5 μm/s. Its gliding machinery comprises hundreds of units that generate the force for gliding based on the energy derived from ATP; the units catch and pull sialylated oligosaccharides fixed to solid surfaces. In this study, we measured the stall force of wild-type and mutant strains of M. mobile carrying a bead manipulated using optical tweezers. The strains that had been enhanced for binding exhibited weaker stall forces than the wild-type strain, indicating that stall force is related to force generation rather than to binding. The stall force of the wild-type strain decreased linearly from 113 to 19 picoNewtons after the addition of 0-0.5 mM free sialyllactose (a sialylated oligosaccharide), with a decrease in the number of working units. After the addition of 0.5 mM sialyllactose, the cells carrying a bead loaded using optical tweezers exhibited stepwise movements with force increments. The force increments ranged from 1 to 2 picoNewtons. Considering the 70-nm step size, this small-unit force may be explained by the large gear ratio involved in the M. mobile gliding machinery.

Genome Sequences of Acholeplasma laidlawii Strains with Increased Resistance to Tetracycline and Melittin

Acholeplasma laidlawii is a well-suited model for studying the molecular basis for adapting mollicutes to environmental conditions. Here, we present the whole-genome sequences of two strains of A. laidlawii with increased resistance to tetracycline and melittin.