Arun Kumar Dutta

Signaling role of nitric oxide in the induction of plant defense by exogenous application of abiotic inducers

The objective of this work was to search out the probable molecule behind the activation of broad spectrum resistance during abiotic elicitors such as arachidonic acid, cupric chloride, chitosan, isonicotinic acid and salicylic acid mediated induced systemic resistance (ISR) in Raphanus sativus L. The elicitor compounds were sprayed on the radish leaves of healthy plant and after 24 h incubation a significant increase of β-1,3 glucanase, peroxidase, polyphenol oxidase and phenolics as well as a remarkable increase of nitric oxide (NO), a probable potent defense-signaling molecule in plant, was observed. Furthermore, treatment of the host with NO donor, sodium nitroprusside, also induced the same defense molecules. The results suggests that NO might be the signaling molecule during abiotic elicitor mediated ISR induction in the host system.

Inventory and spatial ecology of macrofungi in the Shorea robusta forest ecosystem of lateritic region of West Bengal

Macrofungi are broad in diversity and play an important role in sustaining ecosystems. However, the quantity and quality of their habitat is decreasing and the threat of extinction looms over the remaining 95% of the worlds undiscovered fungal species. There is an urgent need for inventorisation, monitoring and conservation of macrofungi and the habitats supporting their growth. This paper focuses on the species richness, assemblage and spatial ecology of the macrofungi whose lifecycles are intricately woven with natural Shorea robusta forests in the lateritic region of West Bengal, India. Decreasing soil productivity, poor regeneration of Shorea seedlings and subsequent habitat degradation for macrofungi are a prime cause of concern.

Macrofungal diversity and habitat specificity: a case study

The diversity of macrofungi in the lateritic region of West Bengal was explored and 120 species, one subgenus and a variety, having eight ecological functions, were found to grow among three types of habitats, i.e. natural forests, plantation forests and villages. Yate’s corrected chi-square (χ2) test statistic was performed upon the 2 × 2 table (contingency table) and testing the null hypotheses of independence of observed cell frequencies of the presence/absence of a species in a given habitat type. Various degrees of specificities of macrofungi to their habitats were observed, i.e. Amanita vaginata, Astraeus hygrometricus, Laccaria laccata, Lactarius zonarius, Porphyrellus malaccensis, Russula brevipes, Russula delica, Russula emetica and Russula laurocerasi were absolutely specific for natural forests; Pisolithus arhizus and Ramaria fumigata were absolutely specific for plantation forests; Auricularia auricula, Schizophyllum commune and Termitomyces clypeatus (only association coefficient 100%) were found to absolutely specific for village habitat. MS Excel-based formulas for calculation of association/specificity of species to habitat and species to species as well as other diversity indices are provided. Local and tribal populations used 19 species of macrofungi during their fruiting period, of which 17 had culinary values and four were locally considered medicinal. This study is a first of its kind, and has various applications to allied disciplines in understanding diversity, ecology and biological prospects of the macrofungal realm.

Prospecting Russula senecis: a delicacy among the tribes of West Bengal.

Russula senecis, a worldwide distributed mushroom, is exclusively popular among the tribal communities of West Bengal for food purposes. The present study focuses on its reliable taxonomic identification through macro- and micro-morphological features, DNA barcoding, confirmation of its systematic placement by phylogenetic analyses, myco-chemicals and functional activities. For the first time, the complete Internal Transcribed Spacer region of R. senecis has been sequenced and its taxonomic position within subsection Foetentinae under series Ingratae of the subgen. Ingratula is confirmed through phylogenetic analysis. For exploration of its medicinal properties, dried basidiocarps were subjected for preparation of a heat stable phenol rich extract (RusePre) using water and ethanol as solvent system. The antioxidant activity was evaluated through hydroxyl radical scavenging (EC50 5 µg/ml), chelating ability of ferrous ion (EC50 0.158 mg/ml), DPPH radical scavenging (EC50 1.34 mg/ml), reducing power (EC50 2.495 mg/ml) and total antioxidant activity methods (13.44 µg ascorbic acid equivalent/mg of extract). RusePre exhibited antimicrobial potentiality against Listeria monocytogenes, Bacillus subtilis, Pseudomonas aeruginosa and Staphylococcus aureus. Furthermore, different parameters were tested to investigate its chemical composition, which revealed the presence of appreciable quantity of phenolic compounds, along with carotenoids and ascorbic acid. HPLC-UV fingerprint indicated the probable existence of at least 13 phenolics, of which 10 were identified (pyrogallol > kaempferol > quercetin > chlorogenic acid > ferulic acid, cinnamic acid > vanillic acid > salicylic acid > p-coumaric acid > gallic acid). Result from the present work suggests that the fraction, RusePre, may open novel prospect as a functional ingredient in antioxidant supplements and in drugs to treat infectious disease.

Macrofungal diversity and ecology of the mangrove ecosystem in the Indian part of Sundarbans

Sundarbans, the world’s largest mangrove biomes, have a rich biodiversity of diverse flora and fauna. Although various attempts had been made previously to explore the diversity of this World Heritage Site, information related to the diversity and ecology of macrofungi in this region is sparse. In this context, the aim of this study was to record the macrofungal diversity and describe the macrofungal communities of this ecosystem whose lifecycles are intricately woven with the mangrove ecosystem of the Indian part of Sundarbans. Carpophore surveys were conducted from June 2010 to September 2012 over 77 randomly placed quadrats (20 × 20 m2). A total of 455 carpophores belonging to 62 species across 27 families and 46 genera were recorded. Of the total number of macrofungal species listed, around 55% were saprophytic. The genera with the greatest species richness were Ganoderma and Tricholoma. Comparing the species richness estimators, the cumulative number of species over the three successive years revealed that 75–100% of potential macrofungal species were recorded. Results from the present study are an important contribution to the knowledge of the macrofungal diversity of the mangrove ecosystems, both in India and worldwide.

Taxonomic and phylogenetic study on gymnopoid fungi from Eastern India. I

Five species of gymnopoid/marasmioid fungi from Eastern India are described based on morphological and molecular (nuclear ribosomal internal transcribed spacer regions and large subunit DNA) sequence data. Of the taxa described, one represents a new species (Marasmiellus foliiphilus), and two (Gymnopus melanopus and Gymnopus menehune) represent first distribution reports from India. Comprehensive descriptions and illustrations are provided for all of the five species. An artificial key of currently reported species of Gymnopus and Marasmiellus from India is provided.

Contribution to the Macromycetes of West Bengal, India: 8–12

Five members of Agaricales (Agrocybe pediades, Calocybella swetha, Cantharocybe virosa, Lepiota echinacea, and Oudemansiella canarii) were collected from different parts of West Bengal, India and are reported herein with detailed morphological characters. Literature survey revealed that all of the collected taxa represent their first distributional record from the state.

Introducing a novel mushroom from mycophagy community with emphasis on biomedical potency

Mushrooms have been prized by humankind as medicine and culinary wonder since antiquity. Though several species are ethnically valued; many prospective species are still being discovered. One such wild macrofungus has recently been discovered during subsequent field surveys in West Bengal, India which in turn exposed as a traditionally consumed popular myco-food. The collected taxon was found to be unique with regard to its morphological as well as genetical features. After detailed characterizations, the fungus was identified as a novel taxon belonging to the genus Russula (Russulaceae, Basidiomycota). Besides, the investigation was further extended in search of new functional ingredients and in this context, a water soluble crude polysaccharide rich extract (Rusalan) was isolated from dried basidiocarps. Accumulating evidences from GC-MS, HPTLC, FT-IR along with several spectrophotometric methods postulated that the fraction consisted mainly of carbohydrate in triple helical conformation, where glucose was the major monosaccharide mostly with β-type glycosidic linkage. Conversely, Rusalan showed pronounced antioxidant activity in six in vitro assay systems with EC50 value ranging from 190–1328 μg/ml concentration. The crude polysaccharide was also evaluated against six bacterial strains using microdilution method and the growth of Staphylococcus aureus and Bacillus subtilis were found to be inhibited effectively. In addition, immune-stimulatory assays demonstrated that Rusalan could evidently promote proliferation, induce phagocytosis, release NO, produce intracellular ROS and upregulate mRNA expression of iNOS, TNF-α, COX-2, as well as IL-6 genes in in mouse macrophage cells. Therefore, aim of the present study was not only to describe a new taxon to the world mycoflora but also to introduce a potent therapeutic agent that could be explored for food and pharmaceutical purposes. However, isolation of active component and in vivo studies need to be designed further.

Microanatomical, Physicochemical characterization, and antioxidative activity of methanolic extract of Oudemansiella canarii (Jungh.) Höhn

Objectives: Oudemansiella canarii is an edible mushroom highly appreciated throughout the world due to its being a gastronomic delicacy. To date, no extensive work has been reported on the pharmacological or antioxidative aspects of this macrofungus. The present study focuses on the micromorphological features, confirmation of its identity based on molecular sequence (nrITS rDNA) data, and determination of its physicochemical parameters such as organoleptic features and fluorescent behavior. Materials and Methods: Collected basidiocarps were powdered and used for microscopic and organoleptic evaluation. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging method, total antioxidant activity methods, and 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay were used for evaluating the antioxidant capacities of the methanolic extract. High-performance liquid chromatography (HPLC) analysis profile was also recorded to analyze the phenolic fingerprint. Results: The DPPH radical scavenging activity was determined with an EC50 value of 0.912 μg, total antioxidant activity was found to be 15.33 μg ascorbic acid equivalent/mg of extract, and the ABTS assay revealed 12.91 μm TE/mg of extract antioxidant activity. The HPLC chromatogram revealed the presence of 12 peaks. Several parameters were tested for the determination of chemical composition, revealing the existence of major bioactive components in the extract in the following order: phenol>flavonoid>ascorbic acid>β-carotene~lycopene. Conclusion: The present work suggests that O. canarii may be considered a novel prospect as a functional food and antioxidant supplement.

Contribution to the Macromycetes of West Bengal, India: 23–27

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