UbiNAAT: a multiplexed point-of-care nucleic acid diagnostic platform for rapid at-home pathogen detection.

The COVID-19 pandemic increased demands for respiratory disease testing to facilitate treatment and limit transmission, demonstrating in the process that most existing test options were too complex and expensive to perform in point-of-care or home scenarios. Lab-based molecular techniques can detect viral RNA in respiratory illnesses but are expensive and require trained personnel, while affordable antigen-based home tests lack sensitivity for early detection in newly infected or asymptomatic individuals. The few home RNA detection tests deployed were prohibitively expensive.

A rapid, instrument-free, sample-to-result nucleic acid amplification test.

The prototype demonstrated here is the first fully integrated sample-to-result diagnostic platform for performing nucleic acid amplification tests that requires no permanent instrument or manual sample processing. The multiplexable autonomous disposable nucleic acid amplification test (MAD NAAT) is based on two-dimensional paper networks, which enable sensitive chemical detection normally reserved for laboratories to be carried out anywhere by untrained users. All reagents are stored dry in the disposable test device and are rehydrated by stored buffer.

Comparison of point-of-care-compatible lysis methods for bacteria and viruses.

Nucleic acid sample preparation has been an especially challenging barrier to point-of-care nucleic acid amplification tests in low-resource settings. Here we provide a head-to-head comparison of methods for lysis of, and nucleic acid release from, several pathogenic bacteria and viruses-methods that are adaptable to point-of-care usage in low-resource settings. Digestion with achromopeptidase, a mixture of proteases and peptidoglycan-specific hydrolases, followed by thermal deactivation in a boiling water bath, effectively released amplifiable nucleic acid from Staphylococcus aureus, Bordetella pertussis, respiratory syncytial virus, and influenza virus.

Posttranslational modification of a vanadium nitrogenase.

In microbes that fix nitrogen, nitrogenase catalyzes the conversion of N2 to ammonia in an ATP-demanding reaction. To help conserve energy some bacteria inhibit nitrogenase activity upon exposure to ammonium. The purple nonsulfur phototrophic bacterium Rhodopseudomonas palustris strain CGA009 can synthesize three functional nitrogenase isoenzymes: a molybdenum nitrogenase, a vanadium nitrogenase, and an iron nitrogenase.

How posttranslational modification of nitrogenase is circumvented in Rhodopseudomonas palustris strains that produce hydrogen gas constitutively.

Nitrogenase catalyzes the conversion of dinitrogen gas (N(2)) and protons to ammonia and hydrogen gas (H(2)). This is a catalytically difficult reaction that requires large amounts of ATP and reducing power. Thus, nitrogenase is not normally expressed or active in bacteria grown with a readily utilized nitrogen source like ammonium.

Production of hydrogen gas from light and the inorganic electron donor thiosulfate by Rhodopseudomonas palustris.

A challenge for photobiological production of hydrogen gas (H(2)) as a potential biofuel is to find suitable electron-donating feedstocks. Here, we examined the inorganic compound thiosulfate as a possible electron donor for nitrogenase-catalyzed H(2) production by the purple nonsulfur phototrophic bacterium (PNSB) Rhodopseudomonas palustris. Thiosulfate is an intermediate of microbial sulfur metabolism in nature and is also generated in industrial processes.

Reversible N epsilon-lysine acetylation regulates the activity of acyl-CoA synthetases involved in anaerobic benzoate catabolism in Rhodopseudomonas palustris.

Rhodopseudomonas palustris grows photoheterotrophically on aromatic compounds available in aquatic environments rich in plant-derived lignin. Benzoate degradation is regulated at the transcriptional level in R. palustris in response to anoxia and the presence of benzoate and/or benzoyl-CoA (Bz-CoA).

Crystal structures of the pilus retraction motor PilT suggest large domain movements and subunit cooperation drive motility.

PilT is a hexameric ATPase required for bacterial type IV pilus retraction and surface motility. Crystal structures of ADP- and ATP-bound Aquifex aeolicus PilT at 2.8 and 3.

Redirection of metabolism for biological hydrogen production.

A major route for hydrogen production by purple photosynthetic bacteria is biological nitrogen fixation. Nitrogenases reduce atmospheric nitrogen to ammonia with the concomitant obligate production of molecular hydrogen. However, hydrogen production in the context of nitrogen fixation is a rather inefficient process because about 75% of the reductant consumed by the nitrogenase is used to generate ammonia.