Jayashree Rout

An antioxidant extract of tropical lichen, Parmotrema reticulatum, induces cell cycle arrest and apoptosis in breast carcinoma cell line MCF-7.

This report highlights the phytochemical analysis, antioxidant potential and anticancer activity against breast carcinoma of 70% methanolic extract of lichen, Parmotrema reticulatum (PRME). Phytochemical analysis of PRME confirms the presence of various phytoconstituents like alkaloids, carbohydrates, flavonoids, glycosides, phenols, saponins, tannins, anthraquinones, and ascorbic acid; among which alkaloids, phenols and flavonoids are found in abundant amount. High performance liquid chromatography (HPLC) analysis of PRME revealed the presence of catechin, purpurin, tannic acid and reserpine. Antioxidant activity was evaluated by nine separate methods. PRME showed excellent hydroxyl and hypochlorous radical scavenging as well as moderate DPPH, superoxide, singlet oxygen, nitric oxide and peroxynitrite scavenging activity. Cytotoxicity of PRME was tested against breast carcinoma (MCF-7), lung carcinoma (A549) and normal lung fibroblast (WI-38) using WST-1 method. PRME was found cytotoxic against MCF-7 cells with an IC50 value 130.03±3.11 µg/ml while negligible cytotoxicity was observed on A549 and WI-38 cells. Further flow cytometric study showed that PRME halted the MCF-7 cells in S and G2/M phases and induces apoptosis in dose as well as time dependent manner. Cell cycle arrest was associated with downregulation of cyclin B1, Cdk-2 and Cdc25C as well as slight decrease in the expression of Cdk-1 and cyclin A1 with subsequent upregulation of p53 and p21. Moreover PRME induced Bax and inhibited Bcl-2 expression, which results in increasing Bax/Bcl-2 ratio and activation of caspase cascade. This ultimately leads to PARP degradation and induces apoptosis in MCF-7 cells. It can be hypothesised from the current study that the antioxidant and anticancer potential of the PRME may reside in the phytoconstitutents present in it and therefore, PRME may be used as a possible source of natural antioxidant that may be developed to an anticancer agent.

Isolation and Characterization of Two Cyanobacterial Strains Calothrix Sp. and Microchaete Sp. from Rice Fields of Karimganj District, Assam, North East India

Studies on various nitrogen fixing microalgal strains found in the rice paddy field soils are carried out in different parts of the world. In the present study two cyanobacterial strains belonging to the order nostocales, Calothrix sp. and Microchaete sp. were isolated from the rice fields of Karimganj district, South Assam, India and characterized based on their morphological, biochemical and molecular analysis. For the phenotypic characterization growth, pigments (chlorophyll a, total carotenoid content, phycobiliproteins) and biochemical properties (total carbohydrate and soluble proteins) were studied. The study showed that both strains contain lower phycoerythrin content as compared to the other pigments. The Microchaete strain contain a higher total carotenoid content while chlorophyll a accumulation was higher in the Calothrix strain. Phylogenetic compairision was made using 16S rRNA gene sequences including other sequences of Calothrix, Microchaete and Tolypothrix species from GenBank. The results showed that polyphasic approach provides necessary information for the identification of cyanobacterial species using morphological analysis in combination with molecular techniques.

Algal Diversity in some selected Vegetable Crop fields of Cachar District, Assam, India

A systematic study of distribution pattern and diversity of algae of vegetable crop fields has been carried out from December 2012 to May 2013 at Irongmara and Barjalenga in Cachar district, Assam. A total of 51 species representing 26 genera were recorded under Chlorophyceae, Bacillariophyceae and Cyanophyceae from the different sampling sites. of these, 22 species belonged to Cyanophyceae, 24 species belonged to Bacillariophyceae and 5 species belonged to Chlorophyceae. The soil pH was found to be mildly acidic in all the plots. It has been observed that Bacillariophyceae contributed major share to soil algal population. Among the species detected, the most dominant are A nabaena, Nostoc, Chroococcus, Oscillatoria, Scenedesmus, Haematococcus, Chlorella, Navicula, Cymbella, and Nitzschia.

Green synthesis of novel antioxidant luminescent silica nanoparticle embedded carbon nanocomposites from a blue-green alga

Abstract Silica nanoparticle embedded carbon 2D-nanocomposite material has been synthesized using a green procedure from a blue green alga, Scytonema guyanense, by direct pyrolysis at 600°C under inert atmosphere. The nanocomposite was characterized by Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), powder X-ray diffraction and energy dispersive spectroscopy (EDS). Characteristic Si-O-Si vibrational absorptions at ~720 cm-1, ~790 cm-1 and ~1080 cm-1 attested the occurrence of silica in the nanocomposite material. Transmission electron microscopy (TEM) analysis revealed five-fold multiply twinned quasi spherical silica nanoparticles (~40 nm) embedded in ~3 nm thick carbon nanoflakes. The material exhibited weak luminescence at 340 nm. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging study showed moderate antioxidant activity of the material.

Community Metrics Under Air Pollution Stress Condition

The chapter deals with the pattern of changes in the diversity components of lichen communities around a paper mill in northeastern Indian region. Four indices (Shannon index, Pielou index, Margalef index, and Simpson index) are calculated for the seventeen sites situated within a radius of 25 km from the mill. The indices are studied vis-a-vis the distance (from the mill) and elevation. Positive correlation is found between number of species and distance, while a negative correlation is found between numbers of species and the elevation. Changes in the pattern of indices are seen along three distance categories; 20 km. As expected, the dominance index increased (54 %) and the diversity, richness, and evenness index decreased near the mill; maximum decrease being for Shannon index (>14 %) of diversity. It is observed that neither of the indices showed significant correlation with the altitude or distance. The Shannon, Margalef, and Simpson index showed significant correlation with the number of species. The effect of stress on biodiversity is depicted with the help of changes in the shapes of Odum’s model of ‘concave’ curve. It is observed from the graphical representation of the ‘number of species’ and ‘number of individual per species’ that the nearness to the mill converted the ‘concave’ hollow curve into a flattened one and ultimately into a ‘convex’ curve.

Exploration of homegardens as important lichen conservation areas in dargakona village of southern assam, Northeast India

Homegardens create a forest like multistory structure with different vertical and horizontal layers and its characteristic species diversity. The present paper throws light on the importance of homegardens as a significant lichen refuge. The study explored a lichen diversity of 44 species with a representation of 17 genera and 9 families. Graphidaceae is the dominant family followed by Pyrenulaceae and Arthoniaceae. Graphis and Pyrenula are found to be the dominant genera representing about 40% of total species richness. It is observed that the homegardens are shelters to about 15% of lichens which have restricted distribution (endemic) in eastern Himalayan region. The traditional wisdom along with ecological knowledge of the local people in maintaining homegardens in northeastern region seems to be helping in conserving the genetic heritage of wild lichen species of eastern Himalayan region. This becomes more important in the wake of wanton destruction of forests and hence lichens growing there.