Transition metals and oxidation reactions trigger stargate opening during the initial stages of the replicative cycle of the giant Tupanvirus.

Tupanviruses, members of the family Mimiviridae, infect phagocytic cells. Particle uncoating begins inside the phagosome, with capsid opening via the stargate. The mechanism through which this opening takes place is unknown. Once phagocytized, metal ion flux control and ROS are induced to inactivate foreign particles, including viruses. Here, we studied the effect of iron ions, copper ions, and H2O2 on Tupanvirus particles. Such treatments induced stargate opening in vitro, as observed by different microscopy techniques. Metal-treated viruses were found to be non-infectious, leading to the hypothesis that stargate opening likely resulted in the release of the viral seed, which is required for infection initiation. To the best of our knowledge, this is the first description of a giant virus capsid morphological change induced by transition metals and H2O2, which may be important to describe new virulence factors and capsid uncoating mechanisms.

Traversing the Cell Wall: The Chitinolytic Activity of Histoplasma capsulatum Extracellular Vesicles Facilitates Their Release.

Histoplasma capsulatum is the causative agent of histoplasmosis. Treating this fungal infection conventionally has significant limitations, prompting the search for alternative therapies. In this context, fungal extracellular vesicles (EVs) hold relevant potential as both therapeutic agents and targets for the treatment of fungal infections. To explore this further, we conducted a study using pharmacological inhibitors of chitinase (methylxanthines) to investigate their potential to reduce EV release and its subsequent impact on fungal virulence in an in vivo invertebrate model. Our findings revealed that a subinhibitory concentration of the methylxanthine, caffeine, effectively reduces EV release, leading to a modulation of H. capsulatum virulence. To the best of our knowledge, this is the first reported instance of a pharmacological inhibitor that reduces fungal EV release without any observed fungicidal effects.

Prevalence of opportunistic invasive aspergillosis in COVID-19 patients with severe pneumonia.

BACKGROUND: As the global coronavirus pandemic (COVID-19) spreads across the world, new clinical challenges emerge in the hospital landscape. Among these challenges, the increased risk of coinfections is a major threat to the patients. Although still in a low number, due to the short time of the pandemic, studies that identified a significant number of hospitalised patients with COVID-19 who developed secondary fungal infections that led to serious complications and even death have been published. OBJECTIVES: In this scenario, we aim to determine the prevalence of invasive fungal infections (IFIs) and describe possible associated risk factors in patients admitted due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. PATIENTS/METHODS: We designed an open prospective observational study at the Rey Juan Carlos University Hospital (Mostoles, Spain), during the period from February 1 to April 30, 2020. RESULTS: In this article, we reported seven patients with COVID-19-associated pulmonary aspergillosis (CAPA) who had a poor prognosis. Severely ill patients represent a high-risk group; therefore, we must actively investigate the possibility of aspergillosis in all of these patients. Larger cohort studies are needed to unravel the role of COVID-19 immunosuppressive therapy as a risk factor for aspergillosis. CONCLUSIONS: As the pandemic continues to spread across the world, further reports are needed to assess the frequency of emergent and highly resistant reemergent fungal infections during severe COVID-19. These coinfections are leading a significant number of patients with COVID-19 to death due to complications following the primary viral disease.