Vineet Meshram

Muscodor kashayum sp. nov. – a new volatile anti-microbial producing endophytic fungus

Muscodor kashayum (MycoBank no.: MB 803800; GenBank no.: KC481680) is a newly described endophytic fungus of a medicinal plant Aegle marmelos (Bael tree), growing in the tropical conserved rainforest in the Western Ghats of India. Muscodor kashayum possesses distinct morphological, molecular and physiological features from the earlier reported Muscodor species. The fungus forms characteristic rings of the ropy mycelium on potato dextrose agar medium. This sterile fungus is characterised by the presence of a pungent smell which is attributable to a blend of more than 23 volatile organic constituents, predominantly 3-cyclohexen-1-ol,1-(1,5-dimethyl-4-hexenyl)-4-methyl; 1,6-dioxacyclododecane-7,12-dione; 2,6-bis(1,1-dimethylethyl)-4-(1-oxopropyl) phenol; 2,4-di-tert-butylthiophenol and 4-octadecylmorpholine. In the in vitro anti-microbial assay using M. kashayum, growth of 75% of test fungi/yeasts and 72% of the test bacteria were completely inhibited. Therefore, M. Kashayum holds potential for future application to be used as a myco-fumigation agent.

Synthesis and Anti-Staphylococcal Activity of 2,4-Disubstituted Diphenylamines

Infections caused by Staphylococcus aureus are ubiquitous and life threatening. Evolution of resistant strains has necessitated the need to continuously discover new drugs to combat such organisms. Diphenyl ethers, such as triclosan, have recently shown potential as antibacterial agents. In this study, a series of diphenyl amines were synthesized and evaluated for in vitro antibacterial activity against Gram-positive (Staphylococcus aureus, Bacillus subtilis, Staphylococcus epidermidis) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa, Pseudomonas putida) bacteria. Preliminary results showed that six of the twelve synthesized molecules were active against Staphylococcus aureus. Most notable amongst them were compounds 2(2,4-dinitrophenylamino)phenol and 2(2-dinitrophenylamino)phenol having minimum inhibitory concentration (MIC) in the range of 7.8-15.6 µg mL-1 and 7.8-62.5 µg mL-1respectively for all the eight selected organisms. Five active compounds from the preliminary results were further screened against resistant S. aureus cultures where compounds 2(2,4-dinitrophenylamino)phenol, 2(2-dinitrophenylamino)phenol and 2-chloro-N-(2-(2,4-dichlorophenylamino)phenyl)acetamide gave encouraging results having MIC in the range 3.9-7.8 µg mL-1for most of the organisms. Results obtained above for the selected organisms and the resistant S. aureus strains conclude that hydroxyl group at 2-position of ring B potentiates the antibacterial activity and overcomes the antibiotic resistance.

Xylarinase: a novel clot busting enzyme from an endophytic fungus Xylaria curta

Abstract Xylarinase is a bi-functional fibrinolytic metalloprotease isolated from the culture filtrate of endophytic fungus Xylaria curta which is monomeric with a molecular mass of ∼33.76 kDa. The enzyme displayed both plasmin and tissue plasminogen activator like activity under in vitro conditions. It hydrolyses Aα and Bβ chains of the fibrinogen. Optimal fibrinolytic activity of xylarinase is observed at 35 °C, pH 8. Ca2+ stimulated the fibrinolytic activity of xylarinase while Fe2+ and Zn2+ inhibited suggesting it to be a metalloprotease. The Km and Vmax values of xylarinase were 240.9 μM and 1.10 U/ml for fibrinogen and 246 μM and 1.22 U/ml for fibrin, respectively. Xylarinase was found to prolong the activated partial thromboplastin time and prothrombin time. The N-terminal sequence of xylarinase (SNGPLPGGVVWAG) did not show any homology with previously known fibrinolytic enzymes. Thus xylarinase is a novel fibrinolytic metalloprotease which could be possibly used as a new clot busting enzyme.

The Biological Promises of Endophytic Muscodor Species

With increasing human population and limited land for agriculture, it has become a herculean task to provide food security to over 7 billion people around the world. The majority of the food produced is lost in postharvest losses. The present approaches to manage the current situation appear to be ineffective and unsustainable. Further, the development of resistance in microbes against the current arsenal of drugs and the destructive effects of methyl bromide and sulfur dioxide on the ozone layer has worsened the situation. This calls for an urgent need to explore alternate avenues for management of postharvest losses. Besides various chemical approaches, exploration of natural resources for finding out new anti-infective and biocontrol agents appears to be a plausible and sustainable solution for management of postharvest losses. Muscodor is a genus of sterile endophytic fungi which has the remarkable property to produce a mixture of volatile organic compounds (VOCs) which are lethal against a number of plant and human pathogenic bacteria and fungi, nematodes, and moths. Further, the VOCs of Muscodor spp. have also shown promising application as biocontrol agent and in management of human waste. Recently, the extrolites of Muscodor species have also shown promising antimicrobial, anti-obesity, antihyperuricemic, and antioxidant activity. Hence, the current chapter embodies the potential uses of volatiles and other extrolites produced by Muscodor species and their possible application in agriculture and pharmaceutical industries.

Endophytes: A Gold Mine of Enzyme Inhibitors

Ever since the landmark discovery of paclitaxel from endophytic Taxomyces andreanae, plant endophytes have been the fountainheads of bioactive secondary metabolites with potential application in medicine, agriculture, and food industry. In the last two decades, lead molecules with antimicrobial, anticancer, antioxidant, and anti-inflammatory properties have been successfully discovered from endophytic microorganisms. Bioprospecting endophytes for enzyme inhibitors has been an important facet of endophytic research. Several enzyme inhibitors like altenusin, huperzine, camptothecin, and podophyllotoxin have been successfully isolated from endophytic microorganisms. The current chapter partially embodies the research progress on endophytic microorganisms for producing bioactive enzyme inhibitors and their possible use in pharmaceutical industries.

Mycoherbicidal Potential of Phaeoacremonium italicum, A New Pathogen of Eichhornia crassipes Infesting Harike Wetland, India

Abstract Mycoherbicides are exclusive biotechnology products which offer a non-chemical solution to control noxious weeds on the land as well as aquatic in systems, viz a viz saving environment from hazardous impact of synthetic chemicals. The present paper highlights the mycobiota associated with Eichhornia crassipes infesting Harike wetland area of Punjab and evaluation of their pathogenic potential for futuristic application as a mycoherbicide. Of the 20 isolates tested by leaf detached assay and whole plant bioassays, only one isolate (#8 BJSSL) caused 100% damage to E. crassipes. Further, the culture filtrate of this isolate also exhibited a similar damage to the leaves in an in vitro detached leaf assay. The potential isolate was identified as Phaeoacremonium italicum using classical and modern molecular methods. This is the first report of P. italicum as a pathogen of E. crassipes and of its potential use as a biological control agent for the management of water hyacinth.

Erratum to: Potential fibrinolytic activity of an endophytic Lasiodiplodia pseudotheobromae species

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