Isolation and characterization of cellulase-producing aeorobic bacterial £ora in the intestine of omnivorous tilapia (Oreochromis mossambica) and phytophagous Chinese grass carp (Ctenopharyngodon idella) have been carried out using selective carboxymethylcellulose-agar (CMC-agar) medium. The cellulolytic activity was measured both qualitatively and quantitatively. It was found that the ability of di¡erent strains in degrading cellulose varies within a wide range. Among the strains isolated from the gut of each test ¢sh, TM1 and CI3 isolated from O. mossambica and C. idella, respectively exhibited maximum cellulolytic activity (67.02 and 35.8 U mL À1 respectively). Pure cultures of these strains were selected for morphological, physiological and biochemical characterization. On the basis of these tests, the isolated strains were identi¢ed as Bacillus circulans (TM1) and Bacillus megaterium (CI3). Both the strains are rod-shaped, motile and show better temperature (15^42 1C) and pH (5^11) tolerance. The selected strains were further quantitatively assayed for amylase and protease activities. Maximum amylase and protease activities were exhibited by TM1 and CI3 respectively. Information generated from the present study might contribute towards better-feed formulation incorporating plant ingredients.

A series of peptides with a long fatty acyl chain covalently attached to the C-terminal part and a free amine (-NH) group at the N-terminus have been designed so that these molecules can be assembled in aqueous medium by using various noncovalent interactions. Five different peptide amphiphiles with a general chemical formula [HN-(CH)CONH-Phe-CONHC (n = 1-5, C = dodecylamine)] have been synthesized, characterized, and examined for self-assembly and hydrogelation. All of these molecules [P1 (n = 1), P2 (n = 2), P3 (n = 3), P4 (n = 4), P5 (n = 5)] form thermoresponsive hydrogels in water (pH 6.6) with a nanofibrillar network structure. Interestingly, the hydrogels obtained from compounds P4 and P5 exhibit potential antimicrobial activity against Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis) and Gram-negative bacteria (Escherichia coli). Dose-dependent cell-viability studies using MTT assay (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) by taking human lung carcinoma (A549) cells vividly demonstrates the noncytotoxic nature of these gelator molecules in vitro. Hemolytic studies show nonsignificant or little hemolysis of human erythrocyte cells at the minimum inhibitory concentration (MIC) of these tested bacteria. Interestingly, it has been found that these antibacterial noncytotoxic hydrogels exhibit proteolytic resistance toward the enzymes proteinase K and chymotrypsin. Moreover, the gel strength and gel recovery time have been successfully modulated by varying the alkyl chain length of the N-terminally located amino acid residues. Similarly, the thermal stability of these hydrogels has been nicely tuned by altering the alkyl chain length of the N-terminally located amino acid residues. In the era of antibiotic-resistant strains of bacteria, the discovery of this new class of peptide-based antibacterial, proteolytically stable, injectable, and noncytotoxic soft materials holds future promise for the development of new antibiotics.

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Background and ObjectiveThe world is currently experiencing the Coronavirus Disease-19 (COVID-19) pandemic. There is no approved drug for the definitive treatment of the disease. Various drugs are being tried for the treatment of COVID-19, including hydroxychloroquine (HCQ). This study was performed to systematically review the therapeutic role of HCQ in COVID-19 from the available literature. Methods PubMed, Embase, ClinicalTrials.gov, ICTRP (WHO), Cochrane Library databases, and two pre-print servers (medRxiv.org and Research Square) were searched for clinical studies that evaluated the therapeutic role of HCQ on COVID-19 until 10 May 2020. The available studies were critically analyzed and the data were extracted. Results A total of 663 articles were screened and 12 clinical studies (seven peer-reviewed and published studies and five non-peer-reviewed studies from pre-print servers) with a total sample size of 3543 patients were included. Some of the clinical studies demonstrated good virological and clinical outcomes with HCQ alone or in combination with azithromycin in COVID-19 patients, although the studies had major methodological limitations. Some of the other studies showed negative results with HCQ therapy along with the risk of adverse reactions. ConclusionThe results of efficacy and safety of HCQ in COVID-19, as obtained from the clinical studies, are not satisfactory, although many of these studies had major methodological limitations. Stronger evidence from well-designed robust randomized clinical trials is required before conclusively determining the role of HCQ in the treatment of COVID-19. Clinical prudence is required in advocating HCQ as a therapeutic armamentarium in COVID-19. Key PointsEfficacy and safety results obtained from clinical studies on the therapeutic role of HCQ in COVID-19 are not satisfactory.The majority of the published studies have major methodological limitations.Safety aspects associated with the use of HCQ along with azithromycin in COVID-19 warrants caution.Large and robust randomized controlled trials will conclusively determine the role of HCQ in COVID-19.

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