Aspergillus Secondary Metabolite Database, a resource to understand the Secondary metabolome of Aspergillus genus.

Aspergillus is a genus of ubiquitous fungi that are pathologically & therapeutically important. Aspergillus Secondary Metabolites Database (A2MDB) is a curated compendium of information on Aspergillus & its secondary metabolome. A2MDB catalogs 807 unique non-redundantsecondary metabolites derived from 675 Aspergillus species. A2MDB has a compilation of 100 cellular targets of secondary metabolites, 44 secondary metabolic pathways, 150 electron and light microscopy images of various Aspergillus species. A phylogenetic representation of over 2500 strains has been provided. A2MDB presents a detailed chemical information of secondary metabolites and their mycotoxins. Molecular docking models of metabolite-target protein interactions have been put together. A2MDB also has epidemiological data representing Aspergillosis and global occurrence of Aspergillus species. Furthermore a novel classification of Aspergillosis along with 370 case reports with images, were made available. For each metabolite catalogued, external links to related databases have been provided. All this data is available on A2MDB, launched through Indian Institute of Chemical Technology, Hyderabad, India, as an open resource http://www.iictindia.org/A2MDB . We believe A2MDB is of practical relevance to the scientific community that is in pursuit of novel therapeutics.

Isolation and characterization of phthalates from Brevibacterium mcbrellneri that cause cytotoxicity and cell cycle arrest.

Bacteria belonging to the family Brevibacterieae are ubiquitous Gram positive organisms that are responsible for the feet odour and cheese aroma. Brevibacterium mcbrellneri is a relatively new member belonging to Brevibacterieae. In the current manuscript we discuss isolation of biologically active metabolites from Brevibacterium mcbrellneri. Two aromatic esters were isolated from Brevibacterium mcbrellneri by "Bioassay guided fractionation strategy" and identified as di-(2-ethylhexyl) phthalate and dibutyl phthalate by chemical characterization using biophysical techniques. The phthalate compounds show broad spectrum antibacterial activity and mosquito larvicidal activity. Mosquito larvicidal activity has been attributed to inhibition of acetylcholinesterase enzyme activity. These compounds were found to be cytotoxic in multiple cell lines causing cell cycle arrest in G1 phase.

Acetylcholinesterase inhibitory activity of stigmasterol & hexacosanol is responsible for larvicidal and repellent properties of Chromolaena odorata.

BACKGROUND: Chromolaena odorata, has been traditionally known for its insect repellent property. Aim of this study was to determine larvicidal tendency of C. odorata on Culex quinquefasciatus and isolate compounds responsible for this activity and to determine the mechanism of action of these compounds. METHODS: C. odorata plant extract was screened for mosquito larvicidal activity. The extract was fractionated using chromatography and the bioactive fraction showing larvicidal activity was identified. The chemical nature of the compounds in the bioactive fraction was determined using NMR and Mass spectrometry. RESULTS: We identified phytosterols and alkanols to be the compounds regulating larvicidal activity in the bioactive fraction of the plant extract. Stigmasterol and 1-hexacosanol were identified to be the chief orchestrators of larvicidal activity and their mode of action has been observed to be neurotoxicity. At a molecular level both stigmasterol and 1-hexacosanol were found to be inhibiting acetylcholinesterase activity in C. quinquefasciatus & A. aegypti. The acetylcholinesterase inhibitory effect was validated in vitro using recombinant acetylcholinesterase and ex vivo in larval homogenates of Culex and Aedes. Electrophysiological studies using electroantennography have shown enhanced neural response to these compounds. CONCLUSIONS: Neurotoxic effect of C. odorata derived stigmasterol and 1-hexacosanol, exerted through acetylcholinesterase inhibition was responsible for the mortality of C. quinquefasciatus, A. aegypti &Chironomus riparius. EAG studies pointed out hyper-excitability of the olfactory system by these compounds. GENERAL SIGNIFICANCE: These compounds are natural agents for mosquito control that can be used in vector control as larvicidal compounds, pending further investigations.

Endophytic Fungi as Novel Resources of natural Therapeutics

ABSTRACT Fungal endophytes constitute a major part of the unexplored fungal diversity. Endophytic fungi (EF) are an important source for novel, potential and active metabolites. Plant-endophyte interaction and endophyte -endophyte interactions study provide insights into mutualism and metabolite production by fungi. Bioactive compounds produced by endophytes main function are helping the host plants to resist external biotic and abiotic stress, which benefit the host survival in return. These organisms mainly consist of members of the Ascomycota, Basidiomycota, Zygomycota and Oomycota. Recently, the genome sequencing technology has emerged as one of the most efficient tools that can provide whole information of a genome in a small period of time. Endophytes are fertile ground for drug discovery. EFare considered as the hidden members of the microbial world and represent an underutilized resource for new therapeutics and compounds. Endophytes are rich source of natural products displaying broad spectrum of biological activities like anticancer, antibacterial, antiviral, immunomodulatory, antidiabetic, antioxidant, anti-arthritis and anti-inflammatory.

Phytofabrication of silver nanoparticles using Myriostachya wightiana as a novel bioresource, and evaluation of their biological activities

ABSTRACT Nanobiotechnology deals with the properties of nanomaterials and their potential uses. Here we report for the first time novel, cost-effective and eco-friendly method for the rapid green synthesis of silver nanoparticles (AgNPs) using leaf extracts of Myriostachya wightiana. The growth of silver nanoparticles was monitored by UV-vis spectroscopy complemented by Zeta potential, dynamic light scattering technique (DLS), Fourier-transform infrared spectroscopy (FTIR), Transmission electron microscope (TEM) and X-ray diffraction (XRD). The surface plasmon resonance (SPR) band found at 434 nm confirmed the reduction of AgNO3 to AgNPs. TEM micrographs revealed that AgNPs are irregular in shape with the size range from 15-65 nm. The functional groups responsible for bio-reduction of silver nitrate into silver were analyzed by FTIR and confirmed by X-ray photoelectron spectrum (XPS). Further these biogenic AgNP were evaluated for insecticidal activities against stored product pests, Tribolium castaneum (Flour beetle), Rhyzopertha dominica (F.)(Lesser grain borer) and Sitophilus oryzae L (Rice weevil). The fabricated AgNPs showed moderate activity on stored pests and strong antibacterial activity with varying degrees against Xanthomonas campestris and Ralstonia solanacearum as evidenced by their zone of inhibition at all concentrations. Hence, these AgNP can be used as control agents against agricultural pests and pathogens in future.