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A new method is developed for protein-protein interaction (PPI) detection in vitro and in cells based on proximity biotinylation. The studies have shown that proximity biotinylation can be applied to different protein pairs.

Once considered a phenotypically monomorphic bacterium, there is a growing body of work demonstrating heterogeneity among Mycobacterium tuberculosis (Mtb) strains in clinically relevant characteristics, including virulence and response to antibiotics. However, the genetic and molecular basis for most phenotypic differences among Mtb strains remains unknown. To investigate the basis of strain variation in Mtb, we performed genome-wide transposon mutagenesis coupled with next-generation sequencing (TnSeq) for a panel of Mtb clinical isolates and the reference strain H37Rv to compare genetic requirements for in vitro growth across these strains. We developed an analytic approach to identify quantitative differences in genetic requirements between these genetically diverse strains, which vary in genomic structure and gene content. Using this methodology, we found differences between strains in their requirements for genes involved in fundamental cellular processes, including redox homeostasis and central carbon metabolism. Among the genes with differential requirements were katG, which encodes the activator of the first-line antitubercular agent isoniazid, and glcB, which encodes malate synthase, the target of a novel small-molecule inhibitor. Differences among strains in their requirement for katG and glcB predicted differences in their response to these antimicrobial agents. Importantly, these strain-specific differences in antibiotic response could not be predicted by genetic variants identified through whole genome sequencing or by gene expression analysis. Our results provide novel insight into the basis of variation among Mtb strains and demonstrate that TnSeq is a scalable method to predict clinically important phenotypic differences among Mtb strains.

Hepatitis C virus (HCV) remains a major public health problem, despite the availability of effective treatments. In many areas, the ability to diagnose HCV infection at the point of care is key to scaling up access to care and treatment. To achieve this, an accurate, easy-to-use, and affordable diagnostic tool is required-this would enable decentralized testing and the creation of one-stop centers to eliminate gaps in the care cascade, which would help reach the millions of people with undiagnosed HCV infection in low- and middle-income countries and high-risk populations in high-income countries. In this review, we examine the current state of point-of-care molecular technologies, the advantages and limitations of currently available devices (both near- and true-point-of-care), the potential of molecular testing to transform diagnostic medicine in the future, and the challenges that need to be addressed for broader adoption of this technology in routine clinical practice., Competing Interests: Potential conflicts of interest. FIND had joint collaborative projects with Cepheid, Molbio, PlusLife, and Sherlock Biosciences and provided financial support to these companies. No financial support from these companies was receieved by FIND or any of the authors. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2023. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)