RESUMO
We report the biochemical, structural, and functional characterization of the protein coded by gene PA4880 in the P. aeruginosa PAO1 genome. The PA4880 gene had been annotated as coding a probable bacterioferritin. Our structural work shows that the product of gene PA4880 is a protein that adopts the Dps subunit fold, which oligomerizes into a 12-mer quaternary structure. Unlike Dps, however, the ferroxidase di-iron centers and iron coordinating ligands are buried within each subunit, in a manner identical to that observed in the ferroxidase center of P. aeruginosa bacterioferritin. Since these structural characteristics correspond to Dps-like proteins, we term the protein as P. aeruginosa Dps-like, or Pa DpsL. The ferroxidase centers in Pa DpsL catalyze the oxidation of Fe2+ utilizing O2 or H2O2 as oxidant, and the resultant Fe3+ is compartmentalized in the interior cavity. Interestingly, incubating Pa DpsL with plasmid DNA results in efficient nicking of the DNA and at higher concentrations of Pa DpsL the DNA is linearized and eventually degraded. The nickase and endonuclease activities suggest that Pa DpsL, in addition to participating in the defense of P. aeruginosa cells against iron-induced toxicity, may also participate in the innate immune mechanisms consisting of restriction endonucleases and cognate methyl transferases.
RESUMO
BACKGROUND: Post-COVID-19 syndrome (PCS; also known as "long COVID") is a relatively novel disease comprising physical, psychological, and cognitive complaints persisting several weeks to months after acute infection with SARS-CoV-2. Approximately 10% of patients with COVID-19 are affected by long-term symptoms. However, effective treatment strategies are lacking. The ErgoLoCo (Occupational Therapy [Ergotherapie] for Long COVID) study was designed to develop and evaluate a novel occupational therapy (OT) concept of online delivery of therapy for long COVID. OBJECTIVE: The primary study objective is to assess the feasibility of the online OT intervention in PCS. Secondary aims include the evaluation of online OT concerning cognitive problems, occupational performance, and social participation. METHODS: This randomized controlled interventional pilot study involves parallel mixed methods process analyses and a realist evaluation approach. A total of 80 clients with PCS aged at least 16 years will be recruited into two interventional groups. The control cohort (watch and wait) comprises 80 clients with long COVID. Treatment is provided through teletherapy (n=40) or delivery of prerecorded videos (n=40) using the same standardized OT concept twice weekly over 12 weeks. Analyses of quantitative questionnaires and qualitative interviews based on the theoretical framework of acceptability will be performed to assess feasibility. Focus group meetings will be used to assess how acceptable and helpful the intervention was to the participating occupational therapists. Standardized tests will be used to assess the initial efficacy of the intervention on neurocognitive performance; limitations in mobility, self-care, and everyday activities; pain; disabilities; quality of life (QoL); social participation; and anxiety and depression in PCS, and the possible effects of online OT on these complaints. RESULTS: The German Ministry of Education and Research provided funding for this research in March 2022. Data collection took place from October 2022 to August 31, 2023. Data analysis will be completed by the end of April 2024. We anticipate publishing the results in the fall of 2024. CONCLUSIONS: Despite the enormous clinical need, effective and scalable treatment options for OT clients who have PCS remain scarce. The ErgoLoCo study will assess whether online-delivered OT is a feasible treatment approach in PCS. Furthermore, this study will assess the effect of the intervention on cognitive symptoms, QoL, and occupational performance and participation in everyday life. Particular emphasis will be placed on the experiences of clients and occupational therapists with digitally delivered OT. This study will pave the way for novel and effective treatment strategies in PCS. TRIAL REGISTRATION: German Clinical Trial Registry DRKS00029990; https://drks.de/search/de/trial/DRKS00029990. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/50230.
