Following the demonstration of the efficacy of hydroxychloroquine against severe acute respiratory syndrome coronavirus 2 in vitro, many trials started to evaluate its efficacy in clinical settings. However, no systematic review and meta-analysis have addressed the issue of the safety and efficacy of hydroxychloroquine (HCQ) in coronavirus disease 2019. We conducted a systematic review and meta-analysis with the objectives of evaluation of safety and efficacy of HCQ alone or in combination in terms of "time to clinical cure," "virological cure," "death or clinical worsening of disease," "radiological progression," and safety. RevMan was used for meta-analysis. We searched 16 literature databases out of which seven studies (n = 1358) were included in the systematic review. In terms of clinical cure, two studies reported possible benefit in "time to body temperature normalization" and one study reported less "cough days" in the HCQ arm. Treatment with HCQ resulted in less number of cases showing the radiological progression of lung disease (odds ratio [OR], 0.31, 95% confidence interval [CI], 0.11-0.9). No difference was observed in virological cure (OR, 2.37, 95% CI, 0.13-44.53), death or clinical worsening of disease (OR, 1.37, 95% CI, 1.37-21.97), and safety (OR, 2.19, 95% CI, 0.59-8.18), when compared with the control/conventional treatment. Five studies reported either the safety or efficacy of HCQ + azithromycin. Although seems safe and effective, more data are required for a definitive conclusion. HCQ seems to be promising in terms of less number of cases with radiological progression with a comparable safety profile to control/conventional treatment. We need more data to come to a definite conclusion.

The N terminal domain (NTD) of Nucleocapsid protein (N protein) of coronavirus (CoV) binds to the viral (þ) sense RNA and results in CoV ribonucleoprotien (CoV RNP) complex, essential for the virus replication. In this study, the RNA-binding N terminal domain (NTD) of the N protein was targeted for the identification of possible inhibitors of RNA binding. Two NTD structures of N proteins were selected (2OFZ and 1SSK, 92% homology) for virtual screening of 56,079 compounds from Asinex and Maybridge library to identify top 15 hits for each of the targets based on 'docking score'. These tophits were further screened for MM-GBSA binding free energy, pharmacokinetic properties (QikProp) and drug-likeness (SwissADME) and subjected to molecular dynamics (MD) studies. Two suitable binders (ZINC00003118440 and ZINC0000146942) against the target 2OFZ were identified. ZINC00003118440 is a theophylline derivative under the drug class 'bronchodilators' and further screening with approved bronchodilators was also studied to identify their ability to bind to the RNA binding region on the N protein. The other identified top hit is ZINC0000146942, which is a 3,4dihydropyrimidone class molecule. Hence this study suggests two important class of compounds, theophylline and pyrimidone derivaties as possible inhibitors of RNA binding to the N terminal domain of N protein of coronavirus, thus opening new avenues for in vitro validations.

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Summary The topoisomerase III (Top3)-Rmi1 heterodimer, which catalyzes DNA single strand passage, forms a conserved complex with the Bloom's helicase (BLM, Sgs1 in budding yeast). This complex has been proposed to regulate recombination by disassembling double-Holliday junctions in a process called dissolution. Top3-Rmi1 has been suggested to act at the end of this process, resolving hemicatenanes produced by earlier BLM/Sgs1 activity. We here show that, to the contrary, Top3-Rmi1 acts in all meiotic recombination functions previously associated with Sgs1, most notably as an early recombination intermediate chaperone, promoting regulated crossover and noncrossover recombination, and preventing aberrant recombination intermediate accumulation. In addition, we show that Top3-Rmi1 has important Sgs1-independent functions that ensure complete recombination intermediate resolution and chromosome segregation. These findings indicate that Top3-Rmi1 activity is important throughout recombination, to resolve strand crossings that would otherwise impede progression through both early steps of pathway choice and late steps of intermediate resolution.

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The recent outbreak of coronavirus disease (COVID-19) caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has already affected a large population of the world. SARS-CoV-2 belongs to the same family of severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV). COVID-19 has a complex pathology involving severe acute respiratory infection, hyper-immune response, and coagulopathy. At present, there is no therapeutic drug or vaccine approved for the disease. There is an urgent need for an ideal animal model that can reflect clinical symptoms and underlying etiopathogenesis similar to COVID-19 patients which can be further used for evaluation of underlying mechanisms, potential vaccines, and therapeutic strategies. The current review provides a paramount insight into the available animal models of SARS-CoV-2, SARS-CoV, and MERS-CoV for the management of the diseases.

Background:The emergence of drug-resistant tuberculosis has called for the discovery of new antitubercular drugs. Results: We successfully generated 24-desmethylrifampicin by modifying the rifamycin polyketide backbone. Conclusion: 24-Desmethylrifamycin showed better antibacterial activity than rifampicin against multidrug-resistant strains of Mycobacterium tuberculosis. Significance: The combined genetic-synthetic strategy used in the study has opened up new avenues for generating more rifamycin analogs.

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