Potential of the salt-tolerant laccase-producing strain Trichoderma viride Pers. NFCCI-2745 from an estuary in the bioremediation of phenol-polluted environments.

Industrialization causes the generation of phenolic pollutants in the environment. The ability of laccases to oxidize phenolic compounds and reduce molecular oxygen to water has led to intensive studies on these enzymes. Although salt-tolerant fungi are potential sources of enzymes for industrial applications, they have been inadequately explored for laccase production. This study describes the isolation of a salt- and phenol-tolerant strain of Trichoderma sp. with the ability to produce laccase, and thus with the potential for industrial applications. The coconut husk retting ground in the estuaries of Kerala, India, a saline environment highly polluted with phenolic compounds, was selected for isolating the fungus. Enhanced laccase production was observed at 5-10 ppt salinity. The organism could grow even at 30 ppt salinity with reduced biomass production and laccase secretion. The optimum concentration of different phenolic compounds for enhanced laccase secretion ranged between 20 and 80 mg L(-1) . As the concentration of phenolic compounds increased beyond 200 mg L(-1) , the enzyme activity decreased and was completely inhibited at 800 mg L(-1) . The tolerance of Trichoderma viride Pers. NFCCI-2745 to salinity and various phenolic compounds can be utilized in the bioremediation of highly saline and phenolic compound-rich industrial effluents.

Elimination of estrogenic activity of thermal paper using laccase from Trichoderma sp NFCCI-2745.

In thermal printing, bisphenol A (BPA) functions chemically as a developer and reacts with white or colorless dyes in the presence of heat, converting them to a dark color. BPA can transfer readily to skin in small amounts from these papers. Its damage to environment and organisms has caused an extensive concern. In the present study, thermal paper used at the local automated teller machine counters of India were analyzed for the presence of BPA, and the capability of the paper to produce estrogenicity were assessed using a yeast two-hybrid assay experimental system. The study also focused on eliminating the endocrine-disrupting properties with partially purified laccase from newly isolated ascomycete fungi. The results indicate that these papers can produce estrogen hormone-like effect on experimental systems. It should be noted that on a daily basis, tons of such receipts are being dumped in the environment. Estrogenic properties of thermal paper were effectively removed from the reaction mixture within 3 h of incubation with the partially purified enzyme. We propose the utilization of waste thermal paper as a cheap substrate for laccase production for a safer and cleaner environment.

Isolation of a salt tolerant laccase secreting strain of Trichoderma sp. NFCCI-2745 and optimization of culture conditions and assessing its effectiveness in treating saline phenolic effluents.

Most of the hazardous pollutants are phenolic in nature and persists in the environment. The ability of laccases to oxidize phenolic compounds and reduce molecular oxygen to water has led to intensive studies of these enzymes. Therefore the fungal strains with high laccase activity and substrate affinity that can tolerate harsh environmental conditions have a potential for biotechnological applications. Salt tolerant laccase secreting fungi can be utilized in treatment of saline and phenolic rich industrial effluents such as coir effluent and textile effluent that needed to be diluted several fold before microbial treatment. This is the first study describing the isolation and optimization of a salt tolerant strain of Trichoderma sp. potential for industrial applications. The fungus was identified based on morphological characteristics and was subsequently confirmed with molecular techniques and deposited at National Fungal Culture Collections of India (NFCCI) under the Accession No. Trichoderma viride NFCCI 2745. In contrast to other laccase secreting fungi, light conditions did not exert much influence on laccase production of this strain and salinity enhanced its laccase secretion. The fungus effectively removed the phenolic content of the textile effluent, coir-ret liquor and wood processing effluent within 96 hr of incubation. The tolerance of the fungus to high salinity and phenolic compounds makes this strain ideal for treating saline and phenolic rich industrial effluents.

Inverted binding due to a minor structural change in berberine enhances its phospholipase A2 inhibitory effect.

Biotransformation of berberine by Rhizopus oryzae leads to its demethylation, producing hydroxyl derivatives, as revealed by Fourier Transform Infra Red spectroscopy, Nuclear Magnetic Resonance and Electro Spray Ionization-Mass Spectrometric analyses. Surface Plasmon Resonance and enzyme kinetic studies showed that biotransformed derivatives of berberine had a higher inhibitory potential than berberine towards phospholipase A(2). X-ray crystal structures demonstrated that biotransformed berberine binds to PLA(2) in an entirely different, inverted orientation with respect to the binding of berberine. This study brings out the significance of biotransformation in generation of better drug-lead compounds.

Evaluation of biotransformed berberine derivatives as anti inflammatory drugs: an in silico study.

The anti inflammatory potential of the human and microbial biotransformed derivatives of berberine were determined by molecular docking. It was revealed that almost all derivatives formed as a result of biotransformation showed increase in phospholipase A(2) binding affinity compared to berberine. The newly introduced -OH group/groups establish stronger hydrogen bonding interactions and more number of van der Waals contacts with the protein. As phospholipase A(2) is a target of anti inflammatory drugs, it might be concluded that certain biotransformed derivatives of berberine could be better anti inflammatory agents compared to berberine.

Identification of a novel and potent inhibitor of phospholipase A(2) in a medicinal plant: crystal structure at 1.93Å and Surface Plasmon Resonance analysis of phospholipase A(2) complexed with berberine.

Crystal of Russell Viper venom phospholipase A(2) complexed with an isoquinoline alkaloid, berberine from a herbaceous plant Cardiospermum halicacabum, was prepared and its structure was solved by X-ray crystallography. The crystal diffracted up to 1.93Å and the structure solution clearly located the position of berberine in the active site of the enzyme. Two hydrogen bonds, one direct and the other water mediated, were formed between berberine and the enzyme. Gly 30 and His 48 made these two hydrogen bonds. Additionally, the hydrophobic surface of berberine made a number of hydrophobic contacts with side chains of neighboring amino acids. Surface Plasmon Resonance studies revealed strong binding affinity between berberine and phospholipase A(2). Enzyme inhibition studies proved that berberine is a competitive inhibitor of phospholipase A(2). It was inferred that the isoquinoline alkaloid, berberine, is a potent natural inhibitor of phospholipaseA(2).

Bisphenol-A can bind to human glucocorticoid receptor as an agonist: an in silico study.

Bisphenol-A (BPA) is a primary monomer in polycarbonate plastics and epoxy resins. BPA may be released into the environment following its formation via hydrolysis of ester bonds of the polymers. It has been detected in human plasma, placenta, amniotic fluid, amniotic chord, urine and saliva. BPA disrupts normal cell function by acting as an estrogen agonist as well as an androgen antagonist. The present study was carried out to investigate whether BPA can bind to human glucocorticoid receptor (GR) and elucidate its mode of interaction. BPA has been successfully docked in silico into the ligand binding site of GR using the program Discovery Studio 2.0. The structure has been compared with other agonist and antagonist bound structures of GR. It is found that the mode of interactions and binding energy of BPA were similar to that of DEXA and cortisol, two known agonists of GR. This reveals that BPA can bind to GR as an agonist. Hence, BPA may produce biological effects similar to that produced by glucocorticoids.