ABSTRACT
The SARS-CoV2 pandemic has created extreme shortages of N95 mask necessitating the need for rapid development of reuse and reprocessing plans. Our aim was to create a process to recapture, reprocess, and redistribute N95 masks using hydrogen peroxide vapor as a real time disinfection method within a large hospital system. We were able to recapture and reprocess 29, 706 N95 masks using hydrogen peroxide vapor with approximately 25% loss due to damage.
Subject(s)
COVID-19/prevention & control , Equipment Reuse , Gases , Hydrogen Peroxide/pharmacology , N95 Respirators/standards , SARS-CoV-2 , Disinfectants/pharmacology , Disinfection/methods , Hospitals , HumansSubject(s)
COVID-19/diagnosis , Mass Screening , Telemetry , Thermography , Body Temperature , COVID-19/epidemiology , COVID-19/prevention & control , Dimensional Measurement Accuracy , Humans , Mass Screening/instrumentation , Mass Screening/methods , Remote Sensing Technology , Reproducibility of Results , SARS-CoV-2 , Telemetry/instrumentation , Telemetry/methods , Tertiary Care Centers , Texas , Thermography/instrumentation , Thermography/methodsABSTRACT
Understanding how enzyme specificity evolves will provide guiding principles for protein engineering and function prediction. The o-succinylbenzoate synthase (OSBS) family is an excellent model system for elucidating these principles because it has many highly divergent amino acid sequences that are <20% identical, and some members have evolved a second function. The OSBS family belongs to the enolase superfamily, members of which use a set of conserved residues to catalyze a wide variety of reactions. These residues are the only conserved residues in the OSBS family, so they are not sufficient to determine reaction specificity. Some enzymes in the OSBS family catalyze another reaction, N-succinylamino acid racemization (NSAR). NSARs cannot be segregated into a separate family because their sequences are highly similar to those of known OSBSs, and many of them have both OSBS and NSAR activities. To determine how such divergent enzymes can catalyze the same reaction and how NSAR activity evolved, we divided the OSBS family into subfamilies and compared the divergence of their active site residues. Correlating sequence conservation with the effects of mutations in Escherichia coli OSBS identified two nonconserved residues (R159 and G288) at which mutations decrease efficiency ≥200-fold. These residues are not conserved in the subfamily that includes NSAR enzymes. The OSBS/NSAR subfamily binds the substrate in a different orientation, eliminating selective pressure to retain arginine and glycine at these positions. This supports the hypothesis that specificity-determining residues have diverged in the OSBS family and provides insight into the sequence changes required for the evolution of NSAR activity.
Subject(s)
Carbon-Carbon Lyases/chemistry , Carbon-Carbon Lyases/metabolism , Conserved Sequence , Escherichia coli/enzymology , Amino Acid Sequence , Carbon-Carbon Lyases/genetics , Catalytic Domain , Computational Biology , Models, Molecular , Mutagenesis, Site-Directed , Mutation , Substrate SpecificityABSTRACT
A 59-year-old pseudophakic woman with a history of Prosed/DS use demonstrated a discolored Tecnis Z9001 (AMO) silicone intraocular lens (IOL). Polymethyl methacrylate (PMMA), hydrophobic acrylic, silicone, and Collamer IOLs were submerged in a physiologic concentration of methylene blue at 35 degrees C for 8 weeks and evaluated. No staining was noted in PMMA or hydrophobic acrylic IOLs, variable staining was noted in silicone IOLs, and intense staining was noted in Collamer IOLs. This is the first report of IOL staining with systemic use of methylene blue and of Collamer lens staining characteristics.
