Effect of rhizospheric inoculation of isolated arsenic (As) tolerant strains on growth, As-uptake and bacterial communities in association with Adiantum capillus-veneris.

Two arsenic (As) hyper-tolerant bacterial strains NM01 Paracoccus versutus and NM04 Aeromonas caviae were isolated from As polluted site of West Bengal, India. The strains not only possess the potential to tolerate up to 20,000 mgl-1 As(V) and 10,000 mgl-1 As(III) but also possess plant growth promoting (PGP) traits like phosphate solubilization, siderophore production, IAA production. Greenhouse pot experiments were conducted to assess the effect of rhizospheric inoculation of both the strains individually and in consortia in As accumulation by Adiantum capillus-veneries. It was observed that the microbial inoculation significantly (p < 0.05) increased the synthesis of thiolic compounds and thus, enhanced As accumulation with translocation factor (TF) > 1. The strains regulated endogenous phytohormone up to 90% and 77.9% increase in auxin of consortia inoculated root and shoot, respectively. Interestingly, inoculation of the isolated strains augmented rhizospheric microbial diversity which was negatively affected by heavy metal. The results of high-throughput Illumina MiSeq sequencing technique to observe the composition of the bacterial community revealed 11,536 unique bacterial operational taxonomic units (OTUs) from As + S (non-inoculated), whereas 11,884 from Consortia As + S (inoculated) rhizospheric soil samples. Inoculated soil displayed higher bacterial diversity indices (ACE and Chao 1) with the dominant bacterial phyla Proteobacteria, Actinobacteria and Firmicutes. Our results highlight the innate PGP abilities of the strains and its potential to facilitate phytoextraction by enhancing As accumulation in the shoot.

Biological evaluation of endophytic fungus, Chaetomium globosum JN711454, as potential candidate for improving drug discovery.

The main objective of this research work focused on investigating the biological and chemical aspects of endophytic fungus Chaetomium globosum, for pharmaceutical purposes to improve the drug discovery process. The endophytic C. globosum was isolated from healthy leaves of Egyptian medicinal plant Adiantum capillus-veneris collected from Saint Katherine Protectorate, Sinai, Egypt. The identification of C. globosum was on the basis of classical and molecular taxonomy. Gene encoding for 18S rRNA was partially sequenced, submitted to the GenBank and got the accession number JN711454, to resolve the phylogenetic relations with fungal ancestor using phylogenetic tree. To explore the biosynthetic power of endophytic C. globosum JN711454, the fungus was cultivated over five different media, oatmeal, rice, yeast malt glucose, potato dextrose agar (PDA) and Czapek's dox media, for 3 weeks at 30 °C, followed by extraction with different solvents, ethyl acetate (EA), and methanol. The ethyl acetate extract of C. globosum cultivated on PDA medium was the most potent extract. It showed strong antioxidant activity with EC50 11.5 µg/ml, potent anticancer activity with 55 % toxicity toward HepG-2 cells at 100 µg/ml and 66 % cytotoxicity to FGC4 cells at 250 µg/ml, promising butyrylcholinesterase inhibitory activities (>85 %), and moderate antimicrobial and stopped the attachment of HSV-2 virus to VERO cells. The metabolomic profiling of PDA-EA extract using LC-MS revealed the presence of several metabolites to which the observed bioactivities could be attributed. Here we report for the first time inhibitory activity of endophytic C. globosum JN711454 secondary metabolites to butyrylcholinesterase, one of neuro hydrolase enzymes that play a major role in development of Alzheimer's disease.