Ammonia-Assimilating Microbes in the Animal Waste Treatment Systems

Ammonia assimilation by microbes is one of important steps of ammonia removal from animal waste treatment systems. We have investigated about distribution and abundance of ammonia-assimilating microbes in the animal waste treatment systems. Ammonia assimilating microorganisms were isolated from the animal waste treatment systems by nitrogen-limited medium. Many of isolates utilized ammonia even when they were cultivated in the media containing viable microbial flora of the animal waste treatment systems. Almost of the dominant species which were detected by analysis of microbial community structure did not coincide with isolates which showed the high ammonia-assimilating ability in the lagoon, but some species by analysis of actinomycetes community structure coincided with the high ammonia-assimilating isolates in the compost. These results suggested that ammonia-assimilating microbes existed as non-dominant species in the microbial community in a lagoon, but some of cultured actinomycetes were the member of dominant species in the actinomycetes community in compost

Molecular and virulence characteristics of an outer membrane-associated RTX exoprotein in Pasteurella pneumotropica

<p>Abstract</p> <p>Background</p> <p><it>Pasteurella pneumotropica </it>is a ubiquitous bacterium that is frequently isolated from laboratory rodents and causes various clinical symptoms in immunodeficient animals. Currently two RTX toxins, PnxIA and PnxIIA, which are similar to hemolysin-like high-molecular-weight exoproteins are known in this species. In this study, we identified and analyzed a further RTX toxin named PnxIIIA and the corresponding type I secretion system.</p> <p>Results</p> <p>The RTX exoprotein, PnxIIIA, contains only a few copies of the RTX repeat-like sequence and 3 large repeat sequences that are partially similar to the outer membrane protein found in several prokaryotes. Recombinant PnxIIIA protein (rPnxIIIA) was cytotoxic toward J774A.1 mouse macrophage cells, whereas cytotoxicity was attenuated by the addition of anti-CD11a monoclonal antibody. rPnxIIIA could bind to extracellular matrices (ECMs) and cause hemagglutination of sheep erythrocytes. Binding was dependent on the 3 large repeat sequences in PnxIIIA. Protein interaction analyses indicated that PnxIIIA is mainly localized in the outer membrane of <it>P. pneumotropica </it>ATCC 35149 in a self-assembled oligomeric form. PnxIIIA is less cytotoxic to J774A.1 cells than PnxIA and PnxIIA.</p> <p>Conclusions</p> <p>The results implicate that PnxIIIA is located on the cell surface and participates in adhesion to ECMs and enhanced hemagglutination in the rodent pathogen <it>P. pneumotropica</it>.</p

Prevalence and analysis of Pseudomonas aeruginosa in chinchillas

<p>Abstract</p> <p>Background</p> <p>Chinchillas (<it>Chinchilla laniger</it>) are popular as pets and are often used as laboratory animals for various studies. <it>Pseudomonas aeruginosa </it>is a major infectious agent that causes otitis media, pneumonia, septicaemia enteritis, and sudden death in chinchillas. This bacterium is also a leading cause of nosocomial infections in humans. To prevent propagation of <it>P. aeruginosa </it>infection among humans and animals, detailed characteristics of the isolates, including antibiotic susceptibility and genetic features, are needed. In this study, we surveyed <it>P. aeruginosa </it>distribution in chinchillas bred as pets or laboratory animals. We also characterized the isolates from these chinchillas by testing for antibiotic susceptibility and by gene analysis.</p> <p>Results</p> <p><it>P. aeruginosa </it>was isolated from 41.8% of the 67 chinchillas included in the study. Slide agglutination and pulsed-field gel electrophoresis discriminated 5 serotypes and 7 unique patterns, respectively. For the antibiotic susceptibility test, 40.9% of isolates were susceptible to gentamicin, 77.3% to ciprofloxacin, 77.3% to imipenem, and 72.7% to ceftazidime. DNA analyses confirmed that none of the isolates contained the gene encoding extended-spectrum β-lactamases; however, 2 of the total 23 isolates were found to have a gene similar to the <it>pilL </it>gene that has been identified in the pathogenicity island of a clinical isolate of <it>P. aeruginosa</it>.</p> <p>Conclusions</p> <p><it>P. aeruginosa </it>is widely spread in chinchillas, including strains with reduced susceptibility to the antibiotics and highly virulent strains. The periodic monitoring should be performed to help prevent the propagation of this pathogen and reduce the risk of infection from chinchillas to humans.</p

The Effect of Grazing on Fecal Shedding of Pathogenic Escherichia coli in Beef Cattle

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In vitro methods to ensure absence of residual undifferentiated human induced pluripotent stem cells intermingled in induced nephron progenitor cells

ヒトiPS細胞から作製した腎前駆細胞に未分化な細胞が残存していないことを確認する方法の開発. 京都大学プレスリリース. 2022-11-16.A new sensitive method to detect for minute amounts of contaminating undifferentiated iPS cells. 京都大学プレスリリース. 2022-11-21.Cell therapies using human induced pluripotent stem cell (hiPSC)-derived nephron progenitor cells (NPCs) are expected to ameliorate acute kidney injury (AKI). However, using hiPSC-derived NPCs clinically is a challenge because hiPSCs themselves are tumorigenic. LIN28A, ESRG, CNMD and SFRP2 transcripts have been used as a marker of residual hiPSCs for a variety of cell types undergoing clinical trials. In this study, by reanalyzing public databases, we found a baseline expression of LIN28A, ESRG, CNMD and SFRP2 in hiPSC-derived NPCs and several other cell types, suggesting LIN28A, ESRG, CNMD and SFRP2 are not always reliable markers for iPSC detection. As an alternative, we discovered a lncRNA marker gene, MIR302CHG, among many known and unknown iPSC markers, as highly differentially expressed between hiPSCs and NPCs, by RNA sequencing and quantitative RT-PCR (qRT-PCR) analyses. Using MIR302CHG as an hiPSC marker, we constructed two assay methods, a combination of magnetic bead-based enrichment and qRT-PCR and digital droplet PCR alone, to detect a small number of residual hiPSCs in NPC populations. The use of these in vitro assays could contribute to patient safety in treatments using hiPSC-derived cells