A yeast-based oral therapeutic delivers immune checkpoint inhibitors to reduce intestinal tumor burden.

Engineered probiotics are an emerging platform for in situ delivery of therapeutics to the gut. Herein, we developed an orally administered, yeast-based therapeutic delivery system to deliver next-generation immune checkpoint inhibitor (ICI) proteins directly to gastrointestinal tumors. We engineered Saccharomyces cerevisiae var.

Genomic Analyses of Longitudinal Mycobacterium abscessus Isolates in a Multicenter Cohort Reveal Parallel Signatures of In-Host Adaptation.

Background: Nontuberculous mycobacteria (NTM) are ubiquitous in the environment and an increasingly frequent cause of opportunistic infections. Mycobacterium abscessus complex (MABC) is one of the major NTM lung pathogens that disproportionately colonize and infect the lungs of individuals with cystic fibrosis (CF). MABC infection can persist for years, and antimicrobial treatment is frequently ineffective.

Starvation sensing by mycobacterial RelA/SpoT homologue through constitutive surveillance of translation.

The stringent response, which leads to persistence of nutrient-starved mycobacteria, is induced by activation of the RelA/SpoT homolog (Rsh) upon entry of a deacylated-tRNA in a translating ribosome. However, the mechanism by which Rsh identifies such ribosomes in vivo remains unclear. Here, we show that conditions inducing ribosome hibernation result in loss of intracellular Rsh in a Clp protease-dependent manner.

Molecular dissection of RbpA-mediated regulation of fidaxomicin sensitivity in mycobacteria.

RNA polymerase (RNAP) binding protein A (RbpA) is essential for mycobacterial viability and regulates transcription initiation by increasing the stability of the RNAP-promoter open complex (RP). RbpA consists of four domains: an N-terminal tail (NTT), a core domain (CD), a basic linker, and a sigma interaction domain. We have previously shown that truncation of the RbpA NTT and CD increases RP stabilization by RbpA, implying that these domains inhibit this activity of RbpA.

Perspectives and Advances in the Understanding of Tuberculosis.

(), the causative agent of tuberculosis (TB), remains a leading cause of death due to infection in humans. To more effectively combat this pandemic, many aspects of TB control must be developed, including better point of care diagnostics, shorter and safer drug regimens, and a protective vaccine. To address all these areas of need, better understanding of the pathogen, host responses, and clinical manifestations of the disease is required.

The stringent response and Mycobacterium tuberculosis pathogenesis.

During infection, the host restrains Mycobacterium tuberculosis (Mtb) from proliferating by imposing an arsenal of stresses. Despite this onslaught of attacks, Mtb is able to persist for the lifetime of the host, indicating that this pathogen has substantial molecular mechanisms to resist host-inflicted damage. The stringent response is a conserved global stress response in bacteria that involves the production of the hyperphosphorylated guanine nucleotides ppGpp and pppGpp (collectively called (p)ppGpp).

Domains within RbpA Serve Specific Functional Roles That Regulate the Expression of Distinct Mycobacterial Gene Subsets.

The RNA polymerase (RNAP) binding protein A (RbpA) contributes to the formation of stable RNAP-promoter open complexes (RP) and is essential for viability in mycobacteria. Four domains have been identified in the RbpA protein, i.e.

Cooperative stabilization of Mycobacterium tuberculosis rrnAP3 promoter open complexes by RbpA and CarD.

The essential mycobacterial transcriptional regulators RbpA and CarD act to modulate transcription by associating to the initiation complex and increasing the flux of transcript production. Each of these factors interacts directly with the promoter DNA template and with RNA polymerase (RNAP) holoenzyme. We recently reported on the energetics of CarD-mediated open complex stabilization on the Mycobacterium tuberculosis rrnAP3 ribosomal promoter using a stopped-flow fluorescence assay.

Major alteration in coxsackievirus B3 genomic RNA structure distinguishes a virulent strain from an avirulent strain.

Coxsackievirus B3 (CV-B3) is a cardiovirulent enterovirus that utilizes a 5' untranslated region (5'UTR) to complete critical viral processes. Here, we directly compared the structure of a 5'UTR from a virulent strain with that of a naturally occurring avirulent strain. Using chemical probing analysis, we identified a structural difference between the two 5'UTRs in the highly substituted stem-loop II region (SLII).