Purification and Characterization of Alkaline Protease from Bacillus sp. HD292

Proceedings of the National Academy of Sciences, India Section B: Biological Sciences - Proteolytic enzymes form a very significant group of enzymes which are used for a variety of purposes...     

MOF derived carbon based nanocomposite materials as efficient electrocatalysts for oxygen reduction and oxygen and hydrogen evolution reactions

The escalating global energy demands and the formidable risks posed by fossil fuels coupled with their rapid depletion have inspired researchers to embark on a quest for sustainable clean energy. Electrochemistry based technologies, e.g., fuel cells, Zn–air batteries or water splitting, are some of the frontrunners of this green energy revolution. The primary concern of such sustainable energy technologies is the efficient conversion and storage of clean energy. Most of these technologies are based on half-cell reactions like oxygen reduction, oxygen and hydrogen evolution reactions, which in turn depend on noble metal based catalysts for their efficient functioning. In order to make such green energy technologies economically viable, the need of the hour is to develop new noble metal free catalysts. Porous carbon, with some assistance from heteroatoms like N or S or earth abundant transition metal or metal oxide nanoparticles, has shown excellent potential in the catalysis of such electrochemical reactions. Metal–organic frameworks (MOFs) containing metal nodes and organic linkers in an ordered morphology with inherent porosity are ideal self-sacrificial templates for such carbon materials. There has been a recent spurt in reports on such MOF-derived carbon based materials as electrocatalysts. In this review, we have presented some of this research work and also discussed the practical reasons behind choosing MOFs for this purpose. Different approaches for synthesizing such carbonaceous materials with unique morphologies and doping, targeted towards superior electrochemical activity, have been documented in this review.

Hetero-atom doped porous carbon materials derived from MOFs are efficient noble metal-free electrocatalysts.     

Green synthesis of gold nanoparticles using an antiepileptic plant extract: in vitro biological and photo-catalytic activities

Gold nanoparticles are one of the widely used metallic nanoparticle having unique surface plasmon characteristic, offers major utility in biomedical and therapeutic fields. However, chemically synthesized nanoparticle creates toxicity in the living organisms and contradicts the eco-friendly and cost-effective nature. So, developing greener synthetic route for synthesis of gold nanoparticle using natural materials is an enthralling field of research for its effectiveness in synthesizing eco-friendly, non-toxic materials. Moreover, biological components attached as stabilizing agent can exert its own effect along with the advantages of nanoparticle conjugation. In this work, we used for the first time methanolic leaf extract of Moringa oleifera as this fraction of M. oleifera exerts a neuroactive modulation against seizure as evidenced by earlier literature. The green gold nanoparticles synthesized were characterized by different characterization tools, dynamic light scattering and transmission electron microscopy techniques etc. Prepared nanoparticles were biologically (antioxidant, antimicrobial and blood cytotoxicity) characterized to screen their further utility in therapeutic strategies. Characteristics and activities of green gold nanoparticles were compared with conventional citrate stabilized gold nanoparticles. It was observed that green gold nanoparticles prepared using M. oleifera show less cytotoxicity and helps in regeneration of neuronal cells in animal model study. It establishes the fact that conjugation of different plant extract fraction for stabilization of gold nanoparticle may be responsible factor for enhancement of bioactive nature of green gold nanoparticle. In addition, the green gold nanoparticle show efficient photo-catalytic efficiency. Development of such bioactive gold nanoparticles will lead to functional materials for biomedical and therapeutic applications.

Gold nanoparticles are one of the widely used metallic nanoparticle having unique surface plasmon characteristic, offers major utility in biomedical and therapeutic fields.     

Post-Harvest Preservation of Whole Kinnow Fruit Using Betel Leaf Extract Coating

Proceedings of the National Academy of Sciences, India Section B: Biological Sciences - The present study aimed at preserving Kinnow using betel leaf (Piper betle L.) extract. The purpose was to...     

In Vitro Antifungal Activities of Bis(Alkylpyridinium)Alkane Compounds against Pathogenic Yeasts and Molds

Ten bis(alkylpyridinium)alkane compounds were tested for antifungal activity against 19 species (26 isolates) of yeasts and molds. We then determined the MICs and minimum fungicidal concentrations (MFCs) of four of the most active compounds (compounds 1, 4, 5, and 8) against 80 Candida and 20 cryptococcal isolates, in comparison with the MICs of amphotericin B, fluconazole, itraconazole, voriconazole, posaconazole, and caspofungin, using Clinical Laboratory and Standards Institutes broth microdulition M27-A3 (yeasts) or M38-A2 (filamentous fungi) susceptibility protocols. The compounds were more potent against Candida and Cryptococcus spp. (MIC range, 0.74 to 27.9 μg/ml) than molds (0.74 to 59.7 μg/ml). MICs against Exophiala were 0.37 to 5.9 μg/ml and as low as 1.48 μg/ml for Scedosporium but ≥25 μg/ml for zygomycetes, Aspergillus, and Fusarium spp. Compounds 1, 4, 5, and 8 exhibited good fungicidal activity against Candida and Cryptococcus, except for Candida parapsilosis (MICs of >44 μg/ml). Geometric mean (GM) MICs were similar to those of amphotericin B and lower than or comparable to fluconazole GM MICs but 10- to 100-fold greater than those for the other azoles. GM MICs against Candida glabrata were <1 μg/ml, significantly lower than fluconazole GM MICs (P < 0.001) and similar to those of itraconazole, posaconazole, and voriconazole (GM MIC range of 0.4 to 1.23 μg/ml). The GM MIC of compound 4 against Candida guilliermondii was lower than that of fluconazole (1.69 μg/ml versus 7.48 μg/ml; P = 0.012). MICs against Cryptococcus neoformans and Cryptococcus gattii were similar to those of fluconazole. The GM MIC of compound 4 was significantly higher for C. neoformans (3.83 μg/ml versus 1.81 μg/ml for C. gattii; P = 0.015). This study has identified clinically relevant in vitro antifungal activities of novel bisalkypyridinium alkane compounds.Invasive fungal disease is a significant cause of morbidity and mortality in seriously ill and immunocompromised patients (16, 26, 35). Despite the recent addition of a new class of antifungal agent (the echinocandins) (20) and more potent, broader-spectrum triazoles such as voriconazole (VRC) and posaconazole (POS) (23, 25), the number of available drugs for treatment of fungal infections remains limited. Many are fungistatic rather than fungicidal, and others are associated with substantial toxicity (4). Furthermore, clinical efficacy may be compromised by intrinsic or acquired drug resistance (29, 34). There is therefore a continuing need to develop and test novel antifungal agents with different modes of action.Targeting of fungal virulence determinants, such as, for example, phospholipase B (PLB), is a potentially fruitful approach to new drug development. PLB is a proven virulence determinant of Candida albicans and Cryptococcus neoformans and is secreted by other pathogenic fungi, including Aspergillus spp. (6, 7, 13). Cryptococcal PLB (PLB1) in particular, has been well characterized (8, 13). As part of a study seeking inhibitors of cryptococcal PLB1, Ganendren et al. identified a novel class of phospholipase inhibitors and observed that the bis(quaternary phosphonium)-alkane 1,12-bis(tributylphosphonium) dodecane dibromide not only inhibited cryptococcal PLB1 but also exhibited in vitro antifungal activity (18).Properties of an “ideal” antifungal agent include ease of manufacture, potent antifungal activity, an excellent safety profile, and low cost. Bis-quaternary ammonium salts, which fulfill the above conditions, have long been recognized as potential antimicrobial agents (21, 32). Other than bisphosphonium salts (as described above) (18), we have previously determined that bisammonium-alkanes with a 12-carbon spacer between the positively charged bisammonium head groups exhibit antifungal activity with MICs of ∼1 to 2.5 μg/ml against C. neoformans and C. albicans and that antifungal activity correlated with inhibition of cryptococcal PLB1 activity (27). Subsequent work on bis(aminopyridinium)alkane molecules indicated that these were also strongly antifungal, but they did not inhibit cryptococcal PLB1. This second class of compounds was significantly less toxic to human erythrocytes than the bisammonium-alkanes (28). Most recently, Obando et al. designed a third novel class of antifungal compound—the bis(alkylpyridinium)alkanes—with combined structural features of the bis(quaternary ammonium)alkanes and bis(aminopyridinium)alkanes (30). The compounds differ from previously described antimicrobial bispyridinium compounds (21, 28) as the pyridinium rings are attached to each other through the ring nitrogen atoms, with alkyl substituents appended directly to the pyridinium rings at the 2-, 3-, or 4-positions; preliminary testing of two of these compounds (compounds 1 and 9 in the present study) against 11 unique fungal strains indicated that they may have useful antifungal activities (30).Given the promising antifungal activity of this class of compounds as observed by Obando et al. (30), we evaluated the in vitro antifungal activities of 10 novel bisalkylpyridinium compounds, including compounds designated in the present study as 1 and 9 (described above); the in vitro hemolytic and cytotoxic activities of these compounds have previously been determined (30). Initially, the 10 compounds were screened for antifungal activity against a panel of key fungal pathogens. The MICs and minimum fungicidal concentrations (MFCs) of four of the most active compounds and MICs of marketed triazoles, amphotericin B (AMB), and caspofungin (CAS) were then determined against a large number of Candida (representing eight species) and cryptococcal isolates.