Project description:Naegleriavirus virions purified from the amoeboflagellate Naegleriaclarki were analysed. The virus infects members of the genus Naegleriaincluding the infamous human pathogen Naegleria fowleri, the causativeagent of the rare but lethal disease primary amoebicmeningoencephalitis.
Project description:Naegleria fowleri, the causative agent of primary amoebic meningoencephalitis (PAM), requires increased research attention due to its high lethality and the potential for increased incidence as a result of global warming. The aim of this study was to investigate the interactions between N. fowleri and host cells in order to elucidate the mechanisms underlying the pathogenicity of this amoeba. A co-culture system comprising human fibrosarcoma cells was established to study both contact-dependent and contact-independent cytopathogenicity. Proteomic analyses of the amoebas exposed to human cell cultures or passaged through mouse brain were used to identify novel virulence factors. Our results indicate that actin dynamics, regulated by Arp2/3 and Src kinase, play a considerable role in amoeba cell ingestion. We have identified three promising candidate virulence factors, namely lysozyme, cystatin and hemerythrin, which may be critical in facilitating N. fowleri evasion of host defenses, migration to the brain and induction of a lethal infection. Long-term co-culture secretome analysis revealed an increase in protease secretion, which enhances N. fowleri cytopathogenicity. Raman microspectroscopy revealed significant metabolic differences between axenic and brain-isolated amoebae, particularly in lipid storage and utilization. Taken together, our findings provide important new insights into the pathogenic mechanisms of N. fowleri and highlight potential targets for therapeutic intervention against PAM.
Project description:We report the application of high-throughput RNA sequencing technology to examine expression profiling of plasma transfer RNA (tRNA)-derived small RNAs (tsRNAs) in children with fulminant myocarditis during acute phase (FM-A group), children with fulminant myocarditis during convalescent phase (FM-C group), and healthy volunteers (Con group). A total of 750 precisely matched tsRNAs were identified in the plasma from the three groups. We find that a total of 13 tsRNAs were differentially expressed in FM-A and CON samples, of which 11 tsRNAs were upregulated and 2 were downregulated, and 694 tsRNAs were excluded ; a total of 8 tsRNAs were differentially expressed in paired FM-C and CON samples, of which 2 tsRNAs were upregulated and 6 were downregulated and 703 tsRNAs were excluded . This study provides new ideas for future research on elucidating the mechanisms of myocarditis through regulating tsRNAs levels.
Project description:<p>We report the case of a 15-year-old female with hypodiploid pre-B acute lymphoblastic leukemia status post allogeneic hematopoietic stem cell transplantation (HCT) from a matched unrelated male donor who presented on transplant day +75 with cardiac arrest due to ventricular fibrillation associated with fulminant myocarditis. Using conventional diagnostics, an exhaustive search for microbial pathogens in the heart biopsy as well as nasopharynx, blood, urine, and endotracheal aspirate was performed but did not uncover a candidate pathogen. The family consented to a research study for the use of unbiased next-generation genomic sequencing for pathogen identification in the myocardial biopsy. DNA sequencing was performed on 1.5 x 10<sup>8</sup> sequencing pairs and no microbial pathogens were identified. Interestingly, a significant component of Y-chromosomal human DNA was identified, suggesting infiltration of at least 10 donor leukocytes per host cell. This finding is grossly consistent with the lymphocyte:myocyte ratio in the biopsy according to visual inspection at 40x magnification. This case merits discussion due to (1) her survival after 17 days of veno-arterial extracorporeal life support (ECLS) and (2) the possibility of cardiotropic graft versus host disease (GVHD).</p>