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Suryanarayanan T.S.,Vivekananda Institute of Tropical Mycology VINSTROM | Suryanarayanan T.S.,Ohio State University | Thirunavukkarasu N.,RKM Vivekananda College | Govindarajulu M.B.,Vivekananda Institute of Tropical Mycology VINSTROM | Gopalan V.,Ohio State University
Fungal Diversity | Year: 2012

Horizontally transmitted endophytes are an ecological group of fungi that infect living plant tissues and survive in them without causing any disease symptoms. Even as facets of the endophyte-plant symbiotic relationship are being uncovered, there is an increasing appreciation of the different growth substrates exploited by endophytes and the vast repertoire of secreted enzymes of these fungi. These attributes exemplify the striking biodiversity of fungal endophytes and should motivate bioprospecting these organisms to identify novel biocatalysts that might help address challenges in medicine, food security, energy production and environmental quality. © 2012 The Mushroom Research Foundation.

Thirunavukkarasu N.,Ramakrishna Mission Vivekananda College | Suryanarayanan T.S.,Vivekananda Institute of Tropical Mycology VINSTROM | Girivasan K.P.,Government Arts College for Men Autonomous | Venkatachalam A.,Vivekananda Institute of Tropical Mycology VINSTROM | And 3 more authors.
Fungal Diversity | Year: 2012

Ten marine sponge species from Rameswaram, southern India were studied for their filamentous fungal symbionts. The results suggest that fungal symbionts of marine sponges are hyperdiverse. Genera such as Acremonium, Alternaria, Aspergillus, Cladosporium, Fusarium and Penicillium were frequently isolated; no true marine fungal species were present. Species of Aspergillus were dominant and co-dominant in all the sponges screened. The fungal isolates produced antialgal, antifungal, antioxidant, antibiotic, antiinsect metabolites. A few fungi produced acetylcholinesterase inhibitors. © Kevin D. Hyde 2011.

Suryanarayanan T.S.,Vivekananda Institute of Tropical Mycology VINSTROM | Govindarajulu M.B.,Vivekananda Institute of Tropical Mycology VINSTROM | Thirumalai E.,Vivekananda Institute of Tropical Mycology VINSTROM | Reddy M.S.,Thapar University | Money N.P.,Miami University Ohio
Fungal Biology | Year: 2011

This study concerns the thermotolerance of spores of mesophilic fungi isolated from a tropical semi-arid habitat subject to dry season fire in the Western Ghats, southern India. Among 25 species of Ascomycota isolated from leaf litter, nine were able to grow after incubation in a drying oven for 2. h at 100 °C; the spores of two of these species survived 2. h incubation at 110 °C, and one survived exposure to 115 °C for 2. h. The range of thermotolerance among mesophilic fungi isolated from the leaf litter was surprising: filamentous fungi from other habitats, including species that colonize scorched vegetation after fires and thermophilic forms occurring in self-heating plant composts, cannot survive even brief exposure to such high temperatures. It is possible that the exceptional heat resistance of the Indian fungi is related to adaptations to surviving fires. Genetic analysis of the physiological mechanisms of heat resistance in these fungi offers prospects for future biotechnological innovations. The discovery of extreme thermotolerance among common saprotrophs shows that this physiological trait may be more widespread than recognized previously, adding to concern about the evolution of opportunistic pathogens on a warmer planet. The fungi in this study are among the most heat-resistant eukaryotes on record and are referred to here as 'Agni's Fungi', after the Hindu God of Fire. © 2011 British Mycological Society.

Venkatachalam A.,Vivekananda Institute of Tropical Mycology VINSTROM | Thirunavukkarasu N.,Mission Research | Suryanarayanan T.S.,Vivekananda Institute of Tropical Mycology VINSTROM
Fungal Ecology | Year: 2015

The rhizome and leaf tissues of 10 seagrass species (seven of the family Cymodoceaceae and three of the family Hydrocharitaceae) collected along the coast of Tamilnadu state, southern India were sampled for the presence of fungal endophytes. A culture-based study revealed that the colonization frequency (CF%) of the endophytes was generally lower than that reported for terrestrial plants and that members of Eurotiomycetes dominate the endophyte assemblage in these marine angiosperms. The CF% of the endophytes was more for the rhizome than for the leaves. Species of Aspergillus, Paecilomyces and Penicillium occurred in high CF% and could be isolated from both the tissue types of seagrasses belonging to both the families. © 2014 Elsevier Ltd and The British Mycological Society.

Suryanarayanan T.S.,Vivekananda Institute of Tropical Mycology VINSTROM | Murali T.S.,Mission Research | Murali T.S.,Manipal University India | Thirunavukkarasu N.,Mission Research | And 4 more authors.
Biodiversity and Conservation | Year: 2011

Fungal endophytes of tropical trees are expected to be exceptionally species rich as a consequence of high tree diversity in the tropics and the purported host restriction among the endophytes. Based on this premise, endophytes have been regarded as a focal group for estimating fungal numbers because their possible hyperdiverse nature would reflect significantly global fungal diversity. We present our consolidated ten-year work on 75 dicotyledonous tree hosts belonging to 33 families and growing in three different types of tropical forests of the NBR in the Western Ghats, southern India. We conclude that endophyte diversity in these forests is limited due to loose host affiliations among endophytes. Some endophytes have a wide host range and colonize taxonomically disparate hosts suggesting adaptations in them to counter a variety of defense chemicals in their hosts. Furthermore, such polyphagous endophytes dominate the endophyte assemblages of different tree hosts. Individual leaves may be densely colonized but only by a few endophyte species. It appears that the environment (the type of forest in this case) has a larger role in determining the endophyte assemblage of a plant host than the taxonomy of the host plant. Thus, different tropical plant communities have to be studied for their endophyte diversity to test the generalization that endophytes are hyperdiverse in the tropics, estimate their true species richness, and use them as a predictor group for more accurate assessment of global fungal diversity. © 2011 Springer Science+Business Media B.V.

Govinda Rajulu M.B.,Mission Research | Thirunavukkarasu N.,Mission Research | Suryanarayanan T.S.,Vivekananda Institute of Tropical Mycology VINSTROM | Ravishankar J.P.,Dg Vaishnav College | And 2 more authors.
Fungal Diversity | Year: 2011

Fungal endophytes isolated from leaves of tree species of the forests of Western Ghats, southern India were screened for chitin modifying enzyme production. Thirtyone of the one hundred and sixty two isolates were positive for chitinase, while different isolates produced isoforms of the enzyme. Many isolates produced chitosanase that acted on chitosan with different degrees of acetylation. Modified chitin and different types of chitosans are used in biomedical applications including wound healing, drug delivery, gene delivery, tissue engineering, in the food industry as preservatives and emulsifying agents, and in biocatalysis. Horizontally transmitted endophytes appear to be a good source for a variety of chitin modifying enzymes with the potential to be used in biotechnology. The possibility of chitin modifying enzymes of endophytes in regulating plant defense against pathogens and pests in vivo should also be addressed. © Kevin D. Hyde 2010.

Suryanarayanan T.S.,Vivekananda Institute of Tropical Mycology VINSTROM
Progress in molecular and subcellular biology | Year: 2012

Seaweeds are being studied for their role in supporting coastal marine life and nutrient cycling and for their bioactive metabolites. For a more complete understanding of seaweed communities, it is essential to obtain information about their interactions with various other components of their ecosystem. While interactions of seaweeds with herbivores such as fish and mesograzers and surface colonizers such as bacteria and microalgae are known, their interactions with marine and marine-derived fungi are little understood. This chapter highlights the need for investigations on the little-known ecological group of fungi, viz. the fungal endosymbionts, that have intimate associations with seaweeds.

Suryanarayanan T.S.,Vivekananda Institute of Tropical Mycology VINSTROM
Botanica Marina | Year: 2012

A few recent investigations have established that marine-derived fungi associated with sponges are an excellent source of novel bioactive metabolites with the potential to function as drugs or drug leads. Given the high species diversity and wide distribution of sponges, it is reasonable to expect that they harbour marine-derived fungi with the ability to produce diverse secondary metabolites. For a more complete realisation of their technological potential, a thorough knowledge of the different taxa of marine-derived fungi associated with sponges is essential. There is scarce information on the interplay between sponges and associated marinederived fungi and between the marine-derived fungi and other sponge endosymbionts. Unravelling such interactions could be useful in recreating the sponge microcosm conditions in vitro for harvesting novel fungal metabolites. This is essential as many genes of fungal secondary metabolism are inactive in axenic cultures. This review addresses these issues by focusing on the isolation, identification, nature of association, secondary metabolites and potential interactions of marine-derived fungi of sponges and presents some future prospects regarding the bioprospecting of these fungi.

Kaushik N.K.,Malaria Research Laboratory | Murali T.S.,Manipal University India | Sahal D.,Malaria Research Laboratory | Suryanarayanan T.S.,Vivekananda Institute of Tropical Mycology VINSTROM
Acta Parasitologica | Year: 2014

Eighty four different fungal endophytes isolated from sea grasses (5), marine algae (36) and leaves or barks of forest trees (43) were grown in vitro and the secondary metabolites secreted by them were harvested by immobilizing them on XAD beads. These metabolites were eluted with methanol and screened using SYBR Green I assay for their antiplasmodial activity against blood stage Plasmodium falciparum in human red blood cell culture. Our results revealed that fungal endophytes belonging to diverse genera elaborate antiplasmodial metabolites. A Fusarium sp. (580, IC50: 1.94 μg ml-1) endophytic in a marine alga and a Nigrospora sp. (151, IC50: 2.88 μg ml-1) endophytic in a tree species were subjected to antiplasmodial activity-guided reversed phase high performance liquid chromatography separation. Purification led to potentiation as reflected in IC50 values of 0.12 μg ml-1 and 0.15 μg ml-1 for two of the fractions obtained from 580. Our study adds further credence to the notion that fungal endophytes are a potential storehouse for a variety of novel secondary metabolites vested with different bioactivities including some that can stall the growth of the malaria parasite. © W. Stefański Institute of Parasitology, PAS.

Suryanarayanan T.S.,Vivekananda Institute of Tropical Mycology VINSTROM
Fungal Ecology | Year: 2013

Many fungi belonging to mostly Ascomycota inhabit living tissues of plants of all major lineages without causing any visible symptoms. Termed horizontally transmitted endophytes, they have been investigated mostly for their capacity to produce bioactive secondary metabolites. However, many questions regarding the interactions between endophytes and their plant hosts, phytophagous insects and other fungi remain unanswered. This review highlights some of these areas of endophyte biology about which very little or no knowledge exists. Information garnered' using modern methodologies' on these grey areas of 'endophytism' (endophytic mode of lifestyle) would help immensely in understanding the evolution of endophytes of aerial plant tissues and in exploiting endophytes in various fields of biotechnology. © 2013 Elsevier Ltd and The British Mycological Society.

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