Botechnology & Bioinformatics

The present study attempted to evaluate the antimicrobial and antioxidant activity of fungal endophytes associated with Centella asiatica and Murraya koengii , the ethnomedicinal plants used in traditional practices . Two endophytic fungi Aspergillus oryzae CeR1 and Colletotrichum gloeosporioides MKL1 were isolated from C. asiatica and M. koengii respectively which were characterized morphologically and by using rDNA-internal transcribed spacer. The total antioxidant power and free radical scavenging activity of the fungal extracts was estimated using the total phenolic content and 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical assay along with the flavonoids and alkaloids content. The DPPH free radical assay showed that the ethanolic extract of endophytic fungi Aspergillus oryzae CeR1 had higher radical scavenging activity than Colletotrichum gloeosporioides MKL1. Antimicrobial activity of fungal extract tested against three bacterial strain namely, Staphylococcus aureus MTCC 96, Streptococcus pyogenes MTCC1925, Enteroccocus faecalis MTCC2729 and one fungal strain Candida albicans MTCC183 showed inhibition of growth of test organisms except Staphylococcus aureus MTCC96.

In the present study, an attempt to evaluate the antimicrobial and antioxidant activity of fungal endophytes inhabiting Emblica officinalis has been made keeping in view the medicinal importance of the selected host plant in Indian traditional practices. A total of four endophytic fungi belonging to Phylum Ascomycetes were isolated from different parts of the plant which were characterized morphologically and by using rDNA-internal transcribed spacer. The most frequently isolated endophyte was Phomopsis sp. The antioxidant activity by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and reducing power assay, and total phenol were evaluated using ethanolic extract of endophytic fungi. DPPH activities in all the ethanolic extract increased with the increase in concentrations. Endophytes, Phomopsis sp. and Xylaria sp. showed highest antioxidant activity and also had the higher levels of phenolics. Antimicrobial activity of fungal extract were tested against four bacteria namely, Escherichia coli MTCC730, Enteroccocus faecalis MTCC2729, Salmonella enterica ser. paratyphi MTCC735 and Streptococcus pyogenes MTCC1925, and the fungus Candida albicans MTCC183. In general, the fungal extracts inhibited the growth of test organisms except E. coli.

Potentilla fulgens L. is an ethno-medicinal plant used for the cure of various ailments by the ethnic tribes of Northeast India. Considering its excessive exploitation for medicinal usage, the present investigation was aimed at screening the plant for associated endophytic fungi to assess their bioactivity like antioxidant and anti-inflammatory activity.

Wild edible mushrooms are consumed by the tribes of Meghalaya in the NorthEastern region of India, as part of their ethnic cuisine because of their favored organoleptic characteristics and traditionally known health benefits. Majority of these mushrooms have not yet been characterized in detail and are slowly shrinking in their natural habitats owing to anthropogenic factors and climate change. In the present study, representative specimens of ten morphologically distinct groups of wild edible mushrooms available in the traditional markets and their respective forest habitats, were subjected to multi-loci molecular characterization using SSU, ITS, RPB1 and RPB2 markers. The species identities inferred for the ten mushroom types using the SSU marker matched their morphological description in the case of four morphological groups only whereas the ITS marker successfully resolved the species identity for nine out of the ten mushroom groups under study. Both the protein coding gene markers RPB1 and RPB2 successfully resolved the species identity for three out of the ten morphologically distinct groups. Finally the most likely identity of the wild edible mushrooms under study has been suggested by matching their unique morphological characteristics with the generated DNA barcoding data. The present molecular characterization reveals the ten widely consumed wild mushroom types of Meghalaya, India to be Gomphus floccosus, Lactarius deliciosus, Lactarius volemus, Cantharellus cibarius, Tricholoma viridiolivaceum, Inocybe aff. sphaerospora, Laccaria vinaceoavellanea, Albatrellus ellisii, Ramaria maculatipes and Clavulina cristata. The final species identity generated by the ITS marker matched more accurately with the morphological characteristics/ appearance of the specimens indicating the ITS region as a reliable barcode for identifying wild edible mushrooms.

Tungrymbai is a fermented indigenous soybean food, common to the ethnic tribes of Meghalaya. The microbial diversity in this food is studied to assess the nature of microbes and their source during spontaneous fermentation. The microorganisms associated with this fermented food are also present in the equipment and materials used during preparation and packing. Various species of lactic acid bacteria, yeasts and spore forming forms were recovered in the isolation process which included Bacillus subtilis (Ehrenberg), Entercoccus faecium (Orla-Jensen) Schleifer and Klipper-Balz, Candida parapsilosis (Ashford) Langeron and Talice, Geotrichum candidum Link, Saccharomyces bayanus Sacc. and Saccharomycopsis fibuligera (Linder) Klocker. The fermenting microbes were found to be associated with the equipments and materials used during the spontaneous fermentation of Tungrymbai. Spore forming forms were isolated from all the materials and equipments used during the process while lactic acid bacteria and yeasts could be isolated only from selective materials.

The North Eastern region of India is undergoing industrial development at a faster rate than expected. Roads form the main system of transportation and communication owing to the hilly topography of the region. Automobiles discharge a number of gaseous and trace metal contaminants. Human activities like stone grinding, road construction and sand milling also increase the atmospheric dust and heavy metal contaminant level. These contaminants get settled on leaf surfaces at roadsides and enter in contact with phylloplane microorganisms. This study compares microorganisms on leaf surfaces of alder (Alnus nepalensis (Betulaceae)) on roadside and non-roadside environments. Two sites dominated by alder were selected. One at a busy road intersection on the National Highway no. 44 in Shillong with high traffic density (8 000-9 000 heavy vehicles/day), taken as the polluted site and the other one in a forest approximately 500 m away from the roadside considered as the unpol-luted site. Analysis of phylloplane microorganisms, lead, zinc, copper, cadmium and sulphur was carried out from leaves. The bacterial population was higher at the unpolluted site. Bacterial population showed a significant negative correlation with lead, zinc, copper, cadmium and sulphur. Similarly, fungal population was higher at the unpolluted site. A total of 29 fungal species were isolated from the phylloplane of A. nepalensis (polluted site 16 species; unpolluted site 28 species). Some fungal forms like Mortierella sp., Fusarium oxysporum and Aureobasidium pollulans were dominant in the polluted site. Numbers of phylloplane fungi and bacteria were significantly reduced in the polluted site. The correlation coefficient indicated a detrimental effect of metals like lead, zinc, copper, cadmium and sulphur on the microbial community of leaf surfaces. The specificity of certain fungi to the unpolluted site may be attributed to their sensitivity to pollution. The predominance of Aureobasidium pollulans, Fusarium oxysporum and Mortierella sp. in the polluted site may be due to their resistance to pollutants in roadside conditions. Rev. Biol. Trop. 56 (3): 1521-1529. Epub 2008 September 30.

Uranium (U)-tolerant aerobic chemo-heterotrophic bacteria were isolated from the sub-surface soils of U-rich deposits in Domiasiat, North East India. The bacterial community explored at molecular level by amplified ribosomal DNA restriction analysis (ARDRA) resulted in 51 distinct phylotypes. Bacterial community assemblages at the U mining site with the concentration of U ranging from 20 to 100 ppm, were found to be most diverse. Representative bacteria analysed by 16S rRNA gene sequencing were affiliated to Firmicutes (51%), Gammaproteobacteria (26%), Actinobacteria (11%), Bacteroidetes (10%) and Betaproteobacteria (2%). Representative strains removed more than 90% and 53% of U from 100 µM and 2 mM uranyl nitrate solutions, respectively, at pH 3.5 within 10 min of exposure and the activity was retained until 24 h. Overall, 76% of characterized isolates possessed phosphatase enzyme and 53% had PIB-type ATPase genes. This study generated baseline information on the diverse indigenous U-tolerant bacteria which could serve as an indicator to estimate the environmental impact expected to be caused by mining in the future. Also, these natural isolates efficient in uranium binding and harbouring phosphatase enzyme and metal-transporting genes could possibly play a vital role in the bioremediation of metal-/radionuclide-contaminated environments.

The phylogenetic relationships of the most dominant and morphologically cryptic endophytic fungal isolates from each of five selected medicinal plants, namely Potentilla fulgens, Osbeckia stellata, Osbeckia chinensis, Camellia caduca, and Schima khasiana of the biodiversity rich state of Meghalaya, were assessed with random amplification of polymorphic DNA and PCR-restriction fragment length polymorphism profiles. Sequencing of the internal transcribed spacer 1, small subunit rRNA and partial β-tubulin gene fragments was also conducted to determine the phylogenetic relationships of these isolates with fungal sequences available in Genbank, NCBI. The identity of the fungal isolates is suggested based on the molecular phy-logenetic data.