Notes

Agrobacterium-Mediated Short-term Change regarding Marchantia Liverworts.
Spliceosome remodeling, executed by conserved adenosine triphosphatase (ATPase)/helicases including Prp2, enables precursor messenger RNA (pre-mRNA) splicing. However, the structural basis for the function of the ATPase/helicases remains poorly understood. Here, we report atomic structures of Prp2 in isolation, Prp2 complexed with its coactivator Spp2, and Prp2-loaded activated spliceosome and the results of structure-guided biochemical analysis. Prp2 weakly associates with the spliceosome and cannot function without Spp2, which stably associates with Prp2 and anchors on the spliceosome, thus tethering Prp2 to the activated spliceosome and allowing Prp2 to function. Pre-mRNA is loaded into a featured channel between the N and C halves of Prp2, where Leu536 from the N half and Arg844 from the C half prevent backward sliding of pre-mRNA toward its 5'-end. Adenosine 5'-triphosphate binding and hydrolysis trigger interdomain movement in Prp2, which drives unidirectional stepwise translocation of pre-mRNA toward its 3'-end. These conserved mechanisms explain the coupling of spliceosome remodeling to pre-mRNA splicing.Inflammasomes function as intracellular sensors of pathogen infection or cellular perturbation and thereby play a central role in numerous diseases. Given the high abundance of NLRP1 in epithelial barrier tissues, we screened a diverse panel of viruses for inflammasome activation in keratinocytes. We identified Semliki Forest virus (SFV), a positive-strand RNA virus, as a potent activator of human but not murine NLRP1B. SFV replication and the associated formation of double-stranded (ds) RNA was required to engage the NLRP1 inflammasome. Moreover, delivery of long dsRNA was sufficient to trigger activation. Biochemical studies revealed that NLRP1 binds dsRNA through its leucine-rich repeat domain, resulting in its NACHT domain gaining adenosine triphosphatase activity. Altogether, these results establish human NLRP1 as a direct sensor for dsRNA and thus RNA virus infection.Spliceosome activation involves extensive protein and RNA rearrangements that lead to formation of a catalytically active U2/U6 RNA structure. At present, little is known about the assembly pathway of the latter and the mechanism whereby proteins aid its proper folding. Here, we report the cryo-electron microscopy structures of two human, activated spliceosome precursors (that is, pre-Bact complexes) at core resolutions of 3.9 and 4.2 angstroms. These structures elucidate the order of the numerous protein exchanges that occur during activation, the mutually exclusive interactions that ensure the correct order of ribonucleoprotein rearrangements needed to form the U2/U6 catalytic RNA, and the stepwise folding pathway of the latter. Structural comparisons with mature Bact complexes reveal the molecular mechanism whereby a conformational change in the scaffold protein PRP8 facilitates final three-dimensional folding of the U2/U6 catalytic RNA.Factor-dependent transcription termination mechanisms are poorly understood. We determined a series of cryo-electron microscopy structures portraying the hexameric adenosine triphosphatase (ATPase) ρ on a pathway to terminating NusA/NusG-modified elongation complexes. An open ρ ring contacts NusA, NusG, and multiple regions of RNA polymerase, trapping and locally unwinding proximal upstream DNA. NusA wedges into the ρ ring, initially sequestering RNA. Captisol Upon deflection of distal upstream DNA over the RNA polymerase zinc-binding domain, NusA rotates underneath one capping ρ subunit, which subsequently captures RNA. After detachment of NusG and clamp opening, RNA polymerase loses its grip on the RNADNA hybrid and is inactivated. Our structural and functional analyses suggest that ρ, and other termination factors across life, may use analogous strategies to allosterically trap transcription complexes in a moribund state.Antimicrobial resistance is a major public health problem globally. Likewise, forms of tuberculosis (TB) resistant to first- and second-line TB medicines present a major challenge for patients, health care workers and health care services. In November 2019, WHO convened an independent international expert panel to review new evidence on the treatment of multi-drug and rifampicin resistant (MDR/RR)-TB, using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.Updated WHO guidelines emerging from this review, published in June 2020, recommend a shorter treatment regimen for patients with MDR/RR-TB not resistant to fluoroquinolones (of 9-11 months), with the inclusion of bedaquiline instead of an injectable agent, making the regimen all oral. For patients with MDR-TB and additional fluoroquinolone resistance, a regimen composed of bedaquiline, pretomanid, and linezolid may be used under operational research conditions (6-9 months). Depending on the drug-resistance profile, extent of TB disease or disease severity, a longer (18-20 months) all oral, individualised treatment regimen may be used. The review of new data in 2019 also allowed WHO to conclude that there are no major safety concerns on the use of bedaquiline for longer than 6 months duration, the use of delamanid and bedaquiline together and the use of bedaquiline during pregnancy, although formal recommendations were not made on these topics.The 2020 revision has highlighted the ongoing need for high-quality evidence and has reiterated the need for clinical trials and other research studies to contribute to the development of evidence-based policy.
Although delamanid has been approved for the treatment of multidrug-resistant tuberculosis (MDR-TB) in numerous regions, in areas where it is not yet registered, it can be accessed as part of salvage therapy-in particular, for those patients with limited treatment options-
the Otsuka Compassionate Use (CU) programme. Here we present the analysis of interim treatment outcomes by 24 weeks of more than 200 multidrug-resistant tuberculosis (MDR-TB) patients globally who received delamanid under the Otsuka CU programme.

We evaluated the treatment efficacy, with respect to culture negativity at 24 weeks, and safety profile of delamanid in a MDR-TB cohort of patients treated under CU between 2014 and 2019.

Among patients who received delamanid as part of a multidrug regimen, 123/202 (61%) had extensively drug-resistant tuberculosis (XDR-TB), 66/202 (33%) had HIV co-infection, and 34/202 (17%) were children ages between 6 and 17 years. Of those patients who were culture positive at delamanid treatment initiation and completed 24 weeks of delamanid treatment in combination with other anti-TB drugs, culture negativity was achieved in 116/147 (79%).
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