Browsing by Author "Alan C. Gange"

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Advances in endophytic research
(Springer India, 2014) Vijay C. Verma; Alan C. Gange
In recent years there has been significant attention paid on the endophytic research by various groups working within this domain. Mutualistic endophytic microbes with an emphasis on the relatively understudied fungal endophytes are the focus of this special book. Plants are associated with micro-organisms: endophytic bacteria and fungi, which live inter- and intra-cellularly without inducing pathogenic symptoms, but have active biochemical and genetic interactions with their host. Endophytes play vital roles as plant growth promoters, biocontrol agents, biosurfactant producers, enzymes and secondary metabolite producers, as well as providing a new hidden repertoire of bioactive natural products with uses in pharmaceutical, agrochemical and other biotechnological applications. The increasing interest in endophytic research generates significant progress in our understanding of the host-endophyte relationship at molecular and genetic level. The bio-prospection of microbial endophytes has led to exciting possibilities for their biotechnological application as biocontrol agent, bioactive metabolites, and other useful traits. Apart from these virtues, the microbial endophytes may be adapted to the complex metabolism of many desired molecules that can be of significant industrial applications. These microbes can be a useful alternative for sustainable solutions for ecological control of pests and diseases, and can reduce the burden of excess of chemical fertilizers for this purpose. This book is an attempt to review the recent development in the understanding of microbial endophytes and their potential biotechnological applications. This is a collection of literature authored by noted researchers having signatory status in endophytic research and summarizes the development achieved so far, and future prospects for further research in this fascinating area of research. © 2014 Springer India. All rights reserved.
Biosynthesis of antimicrobial silver nanoparticles by the endophytic fungus Aspergillus clavatus
(2010) Vijay C. Verma; Ravindra N. Kharwar; Alan C. Gange
Aim: To induce the biosynthesis of silver nanoparticles (AgNPs) using Aspergillus clavatus and evaluate their antimicrobial potential. Materials & methods: Aspergillus clavatus (AzS-275), an endophytic fungus isolated from sterilized stem tissues of Azadirachta indica A. Juss., was challenged with 1 mM AgNO3 solution. The characterization of the AgNPs was carried out by x-ray diffraction spectrometry, transmission-electron microscopy and atomic force microscopy. Results & discussion: The synthesized AgNPs were found to be extracellular, polydispersed spherical or hexagonal particles ranging from 10 to 25 nm in size. Antimicrobial activity was performed using a disc-diffusion method against Candida albicans, Pseudomonas fluorescens and Escherichia coli. The results showed an average minimum inhibitory concentration of 5.83μg ml-1 and minimum fungicidal concentration of 9.7 μg ml -1 against C. albicans. Conclusions: AgNPs can be mycosynthesized extracellularly using A. clavatus as the fungal system, which is highly advantageous over chemical synthesis not only because it can be synthesized on a large scale, but because of the ease of downstream processing and its biomedical application in antimicrobial activity. © 2010 Future Medicine Ltd.
Endophytic actinomycetes from azadirachta indica A. Juss.: Isolation, diversity, and anti-microbial activity
(2009) Vijay C. Verma; Surendra K. Gond; Anuj Kumar; Ashish Mishra; Ravindra N. Kharwar; Alan C. Gange
Endophytic actinomycetes from Azadirachta indica A. Juss. were screened and evaluated for their anti-microbial activity against an array of pathogenic fungi and bacteria. A total of 55 separate isolates were obtained from 20 plants, and 60% of these showed inhibitory activity against one or more pathogenic fungi and bacteria. Actinomycetes were most commonly recovered from roots (54.5% of all isolates), followed by stems (23.6%), and leaves (21.8%). The dominant genus was Streptomyces (49.09% of all isolates), while Streptosporangium (14.5%), Microbispora (10.9%), Streptoverticillium (5.5%), Sacchromonospora sp. (5.5%), and Nocardia (3.6%) were also recovered. Streptomyces isolates AzR 006, 011, and 031 (all from roots) had acute activity against Pseudomonas fluorescens, while AzR027, 032, and 051 (also all from roots) showed activity against Escherichia coli. Meanwhile, an isolate of Nocardia sp. from leaves (AzL025) showed antagonism against Bacillus subtilis. Overall, 32 of the 55 were found to have broad spectrum significant antimicrobial activity, while about 4% of them showed strong and acute inhibition to pathogenic fungi and bacteria. Isolates of Streptomyces AzR031, 008, and 047, Nocardia sp. AzL025, and Streptosporangium sp. AzR 021 and 048 are of particular interest because they showed significant antagonistic activity against root pathogens, including Pythium and Phytophthora sp. Thus, many of the isolates recovered from A. indica in this study may be used in developing potential bio-control agents against a range of pathogenic fungi and bacteria and in the production of novel natural antimicrobial compounds. These results not only further our understanding of plant-microbe interactions but also indicate that there is an untapped resource of endophytic microorganisms that could be exploited in the biotechnological, medicinal, and agricultural industries. © 2008 Springer Science+Business Media, LLC.
Piperine production by endophytic fungus Periconia sp. Isolated from Piper longum L.
(2011) Vijay C. Verma; Emil Lobkovsky; Alan C. Gange; Santosh K. Singh; Satya Prakash
The endophytic fungus Periconia sp. produces piperine (5-(3, 4-methylenedioxyphenyl)-1-piperidinopent-2, 4-dien-1-one) under liquid culture. This is the first report of the alternative source for this chemical other than its host, Piper longum. The highly functionalized fungus-derived piperine exhibits strong antimycobacterial activity against Mycobacterium tuberculosis and M. smegmetis with minimum inhibitory concentrations of 1.74 and 2.62 μg ml-1, respectively. The compound was crystallized and the structure was elucidated by single-crystal X-ray crystallography. This finding is of significance as piperine is a potential cancer preventative agent. It is reaffirmed by this report that important pharmaceuticals can be produced by endophytic microbes, and these molecules appear to be mimetic to their host origin. Therefore, we can enhance the bioactive principles of medicinal plants by isolating and identifying the endophytes, thereby showing the importance of preserving the biodiversity of these plants. © 2011 Japan Antibiotics Research Association All rights reserved.