Biological enrichment of Mycoplasma agents by cocultivation with permissive cell cultures

Pseudocapillaria tomentosa, Mycoplasma spp., and Intestinal Lesions in Experimentally Infected Zebrafish Danio rerio

Intestinal neoplasms and preneoplastic lesions are common in zebrafish research facilities. Previous studies have demonstrated that these neoplasms are caused by a transmissible agent, and two candidate agents have been implicated: a Mycoplasma sp. related to Mycoplasma penetrans and the intestinal parasitic nematode, Pseudocapillaria tomentosa, and both agents are common in zebrafish facilities. To elucidate the role of these two agents in the occurrence and severity of neoplasia and other intestinal lesions, we conducted two experimental inoculation studies. Exposed fish were examined at various time points over an 8-month period for intestinal histopathologic changes and the burden of Mycoplasma and nematodes. Fish exposed to Mycoplasma sp. isolated from zebrafish were associated with preneoplastic lesions. Fish exposed to the nematode alone or with the Mycoplasma isolate developed severe lesions and neoplasms. Both inflammation and neoplasm scores were associated with an increase in Mycoplasma burden. These results support the conclusions that P. tomentosa is a strong promoter of intestinal neoplasms in zebrafish and that Mycoplasma alone can also cause intestinal lesions and accelerate cancer development in the context of nematode infection.

Ecological and evolutionary drivers of haemoplasma infection and bacterial genotype sharing in a Neotropical bat community

Most emerging pathogens can infect multiple species, underlining the importance of understanding the ecological and evolutionary factors that allow some hosts to harbour greater infection prevalence and share pathogens with other species. However, our understanding of pathogen jumps is based primarily around viruses, despite bacteria accounting for the greatest proportion of zoonoses. Because bacterial pathogens in bats (order Chiroptera) can have conservation and human health consequences, studies that examine the ecological and evolutionary drivers of bacterial prevalence and barriers to pathogen sharing are crucially needed. Here were studied haemotropic Mycoplasma spp. (i.e., haemoplasmas) across a species-rich bat community in Belize over two years. Across 469 bats spanning 33 species, half of individuals and two-thirds of species were haemoplasma positive. Infection prevalence was higher for males and for species with larger body mass and colony sizes. Haemoplasmas displayed high genetic diversity (21 novel genotypes) and strong host specificity. Evolutionary patterns supported codivergence of bats and bacterial genotypes alongside phylogenetically constrained host shifts. Bat species centrality to the network of shared haemoplasma genotypes was phylogenetically clustered and unrelated to prevalence, further suggesting rare-but detectable-bacterial sharing between species. Our study highlights the importance of using fine phylogenetic scales when assessing host specificity and suggests phylogenetic similarity may play a key role in host shifts not only for viruses but also for bacteria. Such work more broadly contributes to increasing efforts to understand cross-species transmission and the epidemiological consequences of bacterial pathogens.

Imported biologicals: unforeseen biosecurity risks in the laboratory

Imported biological products are ubiquitous necessities of modern life that can pose significant biosecurity risks to Australia. Products produced using animal material are used everywhere from enzymes in cleaning products, to cell lines and bacterial cultures used to produce vaccines and medicines. This article highlights adventitious agents of biologicals and provides an overview of the considerations and regulatory tools administered under the Biosecurity Act 2015 (Commonwealth) to manage these biosecurity risks whilst still facilitating imports of biologicals.

Evaluation of mycoplasma removal reagents using qPCR-based quantification

In this study, we evaluated the efficacy of various mycoplasma removal reagents using nuclear staining, DNA gel electrophoresis, and qPCR-based quantification. Our results showed Plasmocure and Plasmocin are two effective anti-mycoplasma reagents whose effects can be observed within a week. However, prolonged treatment with Plasmocin led to development of resistance. Withdrawal of anti-mycoplasma reagents led to reoccurrence of mycoplasma contamination, but addition of prevention reagent, such as Primocin, prevented recontamination. Therefore, sequential treatment by Plasmocure and Primocin is the best course of action against mycoplasma contamination. Lastly, we developed methods based on qPCR to estimate the average number of mycoplasma associated with a single contaminated cell. We have shown, for the first time, that untreated contaminated BEAS-2B cells have approximately 300-400 mycoplasma contaminants per cell in the cytoplasm or attached to the cell membrane. Furthermore, withdrawal of anti-mycoplasma reagents led to reoccurrence of mycoplasma contamination within two days, and therefore continued use of prevention reagent is imperative.

Whole-Genome Sequence of Sphingomonas sp. Strain FARSPH, a Novel Sf9 Insect Cell Culture Contaminant

Here, we report the whole-genome sequence of Sphingomonas sp. strain FARSPH, isolated from an insect cell line as a contaminant. FARSPH shared high identity with Sphingomonas melonis and Sphingomonas aquatilis strains. Due to this finding, we recommend taking this genus into consideration for cell culture quality control.

Prevalence, Genotype Richness, and Coinfection Patterns of Hemotropic Mycoplasmas in Raccoons (Procyon lotor) on Environmentally Protected and Urbanized Barrier Islands

Raccoons (Procyon lotor) are successful urban adapters and hosts to a number of zoonotic and nonzoonotic pathogens, yet little is known about their hemoplasma infections and how prevalence varies across habitat types. This study identifies hemotropic Mycoplasma species infection in raccoons from urban and undisturbed habitats and compares hemoplasma infection in sympatric urban cats (Felis catus) from the same geographic region. We collected blood from raccoons (n = 95) on an urban coastal island (n = 37) and an undisturbed coastal island (n = 58) and from sympatric urban cats (n = 39) in Georgia, USA. Based on 16S rRNA gene amplification, 62.1% (59/95) of raccoons and 17.9% (7/39) of feral cats were positive for hemoplasma. There was a greater percentage of hemoplasma-infected raccoons on the undisturbed island (79.3% [46/58]) than on the urban island (35.1% [13/37]; χ2 = 16.9, df = 1, P = 0.00004). Sequencing of the full-length 16S rRNA gene amplicons revealed six hemoplasma genotypes in raccoons, including five novel genotypes that were distinct from three known hemoplasma species identified in the sympatric cats. In addition, the hemoplasma genotypes detected in raccoons were not identified in sympatric cats or vice versa. Although all six hemoplasma genotypes were found in raccoons from urban and undisturbed islands, coinfection patterns differed between sites and among individuals, with the proportion of coinfected raccoons being greater in the undisturbed site. This study shows that raccoons are hosts for several novel hemoplasmas and that habitat type influences infection patterns.IMPORTANCE This study provides information about novel hemoplasmas identified in raccoons (Procyon lotor), which can be used for assessments of the prevalence of these hemoplasmas in raccoon populations and for future studies on the potential pathogenic impacts of these hemoplasmas on raccoon health. Raccoons from the undisturbed habitat had a higher prevalence of hemoplasma infection than urban raccoons. There does not appear to be cross-species transmission of hemotropic mycoplasmas between urban raccoons and feral cats. Raccoons appear to be hosts for several novel hemoplasmas, and habitat type influences infection patterns.

Intrauterine growth restriction perturbs nucleosome depletion at a growth hormone-responsive element in the mouse IGF-1 gene

Intrauterine growth restriction (IUGR) is a common human pregnancy complication. IUGR offspring carry significant postnatal risk for early-onset metabolic syndrome, which is associated with persistent reduction in IGF-1 protein expression. We have previously shown that preadolescent IUGR male mice have decreased hepatic IGF-1 mRNA and circulating IGF-1 protein at postnatal day 21, the age when growth hormone (GH) normally upregulates hepatic IGF-1 expression. Here we studied nucleosome occupancy and CpG methylation at a putative growth hormone-responsive element in intron 2 (in2GHRE) of the hepatic IGF-1 gene in normal, sham-operated, and IUGR mice. Nucleosome occupancy and CpG methylation were determined in embryonic stem cells (ESCs) and in liver at postnatal days 14, 21, and 42. For CpG methylation, additional time points out to 2 yr were analyzed. We confirmed the putative mouse in2GHRE was GH-responsive, and in normal mice, a single nucleosome was displaced from the hepatic in2GHRE by postnatal day 21, which exposed two STAT5b DNA binding sites. Nucleosome displacement correlated with developmentally programmed CpG demethylation. Finally, IUGR significantly altered the nucleosome-depleted region (NDR) at the in2GHRE of IGF-1 on postnatal day 21, with either complete absence of the NDR or with a shifted NDR exposing only one of two STAT5b DNA binding sites. An NDR shift was also seen in offspring of sham-operated mothers. We conclude that prenatal insult such as IUGR or anesthesia/surgery could perturb the proper formation of a well-positioned NDR at the mouse hepatic IGF-1 in2GHRE necessary for transitioning to an open chromatin state.

Sensitivity of biochemical test in comparison with other methods for the detection of mycoplasma contamination in human and animal cell lines stored in the National Cell Bank of Iran

Mycoplasma contamination in cell culture is considered as serious problem in the manufacturing of biological products. Our goal in this research is to find the best standard and rapid method with high sensitivity, specificity, accuracy and predictive values of positive and negative results for detection of mycoplasma contamination in cell cultures of the National Cell Bank of Iran. In this study, 40 cell lines suspected to mycoplasma contamination were evaluated by three different methods: microbial culture, enzymatic mycoalert(®) and molecular. Enzymatic evaluation was performed using the mycoalert(®) kit while in the molecular technique, a universal primer pair was designed based on the common and fixed 16SrRNA ribosomal sequences used. Mycoplasma contaminations in cell cultures with molecular, enzymatic and microbial culture methods were determined as 57.5, 52.5 and 40 %, respectively. These results confirmed the higher rate of sensitivity, specificity and accuracy for the molecular method in comparison with enzymatic and microbial methods. Polymerase chain reaction (PCR) assay based on fixed and common sequences in the 16SrRNA, is a useful valuable and reliable technique with high sensitivity, specificity and accuracy for detection of mycoplasma contamination in cell cultures and other biological products. The enzymatic mycoalert(®) method can be considered as a substitution for conventional microbial culture and DNA staining fluorochrome methods due to its higher sensitivity, specificity and speed of detection (<20 min).

Dye free automated cell counting and analysis

We have developed an automated cell counting method that uses images obtained at multiple focal heights to enumerate cells in confluent culture. By taking the derivative of image intensity with respect to focal height using two complementary images, we are able to count high-density monolayers of cells over a large image area. Our method resists errors arising from variability in the focal plane caused by flatness or tilt non-uniformities with a minimal amount of focal plane alignment, allowing the automated collection of images across a large area.

Identification of Mycoplasmas using a fluorophore-free microarray and infrared chemical imaging (IRCI)

A novel application of mid-infrared chemical imaging (IRCI) for the fluorophore-free detection and identification of mycoplasma species is reported for the first time. The PCR-amplified biotinylated targets hybridized to microarray probes were treated with streptavidin-gold nanoparticles followed by silver enhancement. This modification has the potential to expand the implementation of DNA microarray techniques in laboratories involved in the detection of cell substrates, other biological products, and clinical materials for the presence of mycoplasmas.

Detection of Mollicutes in bioreactor samples by real-time transcription-mediated amplification

AIM

Contamination by Mollicutes is a significant challenge for research laboratories and biopharmaceutical industry. It leads to alteration of results or production quality as well as loss of time, materials and revenue. These organisms can czoriginate from mammalian, avian, insect, plant or fish cells. Culture-based methods may require 28 days to detect Mollicutes. Traditional microbiology could advantageously be replaced by nucleic acid testing for earlier detection.

METHODS AND RESULTS

A membrane filtration-based concentration of the Mollicutes has been coupled to real-time transcription-mediated amplification (real-time TMA) to demonstrate these advantages. The eight species required by European Pharmacopoeia have been tested and were detected with sensitivity below 100 CFU per 20-ml sample. Co-culture experiments, in which Mollicutes are grown with CHO-S (suspension) or HEK 293 (adherent) cells, were also performed to respectively mimic a bioreactor or flask contamination. Despite the fact that Mollicutes can attach to or invade mammalian cells, they were consistently detected over multiple days.

CONCLUSIONS

the sample preparation and amplification method used in this study increases sensitivity and reduces time-to-result for detection of Mollicutes.

SIGNIFICANCE AND IMPACT OF THE STUDY

the described system allows real-time monitoring for microbial contamination of cell-based processes and products for the biopharmaceutical industry.

Evaluation of Mycoplasma inactivation during production of biologics: egg-based viral vaccines as a model

Although mycoplasmas are generally considered to be harmless commensals, some mycoplasma species are able to cause infections in pediatric, geriatric, or immunocompromised patients. Thus, accidental contamination of biologics with mycoplasmas represents a potential risk for the health of individuals who receive cell-derived biological and pharmaceutical products. To assess the efficiency of inactivation of mycoplasmas by the agents used in the manufacture of egg-derived influenza vaccines, we carried out a series of experiments aimed at monitoring the viability of mycoplasmas spiked into both chicken allantoic fluid and protein-rich microbiological media and then treated with beta-propiolactone, formalin, cetyltrimethylammonium bromide, Triton X-100, and sodium deoxycholate, which are agents that are commonly used for virus inactivation and disruption of viral particles during influenza vaccine production. Twenty-two mycoplasma species (with one to four strains of each species) were exposed to these inactivating agents at different concentrations. The most efficient inactivation of the mycoplasmas evaluated was observed with either 0.5% Triton X-100 or 0.5% sodium deoxycholate. Cetyltrimethylammonium bromide at concentrations of >or=0.08% was also able to rapidly inactivate (in less than 30 min) all mycoplasmas tested. In contrast, negligible reductions in mycoplasma titers were observed with 0.0125 to 0.025% formaldehyde. However, increasing the concentration of formaldehyde to 0.1 to 0.2% improved the mycoplasmacidal effect. Incubation of mycoplasmas with 0.1% beta-propiolactone for 1 to 24 h had a marked mycoplasmacidal effect. A comparison of the mycoplasma inactivation profiles showed that strains of selected species (Mycoplasma synoviae, Mycoplasma gallisepticum, Mycoplasma orale, Mycoplasma pneumoniae, and Acholeplasma laidlawii) represent a set of strains that can be utilized to validate the effectiveness of mycoplasma clearance obtained by inactivation and viral purification processes used for the manufacture of an inactivated egg-based vaccine.