Four marine-derived fungi for bioremediation of raw textile mill effluents

Textile dye effluents pose environmental hazards because of color and toxicity. Bioremediation of these has been widely attempted. However, their widely differing characteristics and high salt contents have required application of different microorganisms and high dilutions. We report here decolorization and detoxification of two raw textile effluents, with extreme variations in their pH and dye composition, used at 20–90% concentrations by each of the four marine-derived fungi. Textile effluent A (TEA) contained an azo dye and had a pH of 8.9 and textile effluent B (TEB) with a pH of 2.5 contained a mixture of eight reactive dyes. The fungi isolated from mangroves and identified by 18S and ITS sequencing corresponded to two ascomycetes and two basidiomycetes. Each of these fungi decolorized TEA by 30–60% and TEB by 33–80% used at 20–90% concentrations and salinity of 15 ppt within 6 days. This was accompanied by two to threefold reduction in toxicity as measured by LC₅₀ values against Artemia larvae and 70–80% reduction in chemical oxygen demand and total phenolics. Mass spectrometric scan of effluents after fungal treatment revealed degradation of most of the components. The ascomycetes appeared to remove color primarily by adsorption, whereas laccase played a major role in decolorization by basidiomycetes. A process consisting of a combination of sorption by fungal biomass of an ascomycete and biodegradation by laccase from a basidiomycete was used in two separate steps or simultaneously for bioremediation of these two effluents.     

Vibrational analysis of peptides, polypeptides and proteins. XXVII. Structure of gramicidin S from normal mode analyses of low-energy conformations

Normal mode calculations have been carried out on three low-energy structures of gramicidin S obtained from conformational energy calculations. When the results on the amide modes are compared with observed bands in the infrared and Raman spectra of crystalline gramicidin S and its N-deuterated derivative, one of the structures is clearly disfavored. Of the other two, one is slightly favored, and it corresponds to the lowest-energy structure obtained from the energy calculations. Spectra from solutions in DMSO and CH3 OH suggest that the molecular conformation is essentially retained in these solvents.     

Quenching of fluorescence by meclizine,a probe study for structural and conformational changes in human serum albumin

The goal of this study was to investigate the interactions between meclizine (MEC) and human serum albumin (HSA) under physiological conditions by different spectroscopies and molecular modeling technique. The drug, MEC quenched the intrinsic fluorescence of HSA and the analysis of the results revealed that static quenching mechanism. The binding of MEC quenches the HSA fluorescence; stoichiometry was 1:1 interaction. Thermodynamic quantities were calculated at different temperatures suggested that hydrophobic and van der Waals interaction with HSA–MEC. The molecular distance, r, between donor and acceptor was estimated according to Forster’s theory of non-radiation energy transfer. CD and FT-IR studies confirm changes of secondary structure of HSA. Molecular docking studies validate MEC molecule interact to HSA in sub domain IIA.     

Microwave-assisted synthesis,molecular docking and antitubercular activity of 1,2,3,4-tetrahydropyrimidine-5-carbonitrile derivatives

Based on bioisosteric similarities with isoniazid, a series of 1,2,3,4-tetrahydropyrimidine-5-carbonitrile derivatives has been designed. The target compounds have been synthesized by multicomponent reaction which involves one-pot organic reactions using ethylcyanoacetate, urea/thiourea and arylaldehydes in presence of ethanolic K₂CO₃. Two methodologies, conventional and microwave-assisted, have been adopted for the synthesis. The later strategy gave high yields in less than 10 min as compared to long hours using the former approach. Molecular docking of the target compounds into the enzyme Mycobacterium tuberculosis enoyl reductase (InhA) revealed important structural information on the plausible binding interactions. Major binding interactions were found to be of dispersion type (residues Tyr158, Ile215, Met103 and Met199) and a hydrogen bond with Tyr158. Binding poses of the all the compounds were energetically favorable and showed good interactions with the active site residues. Few selected compounds were also evaluated for antitubercular activity in vitro against drug-sensitive M. tuberculosis H37Rv strain and clinically isolated S, H, R and E resistant M. tuberculosis by luciferase reporter phage (LRP) assay method. Some compounds displayed promising antimycobacterial activity comparable or less than the standard drugs isoniazid and rifampicin.     

Cell-mediated resistance induced by axenic amoebal RNA--protein fraction

Immunologically potent, RNA protein fraction could be isolated from axenic Entamoeba histolytica (NIH: 200) using a phenol extraction method. Immunization of animals with amoebal RNA protein (Eh RNA) fraction evoked an intense cellular sensitization. In immunized animals the percent leucocyte migration inhibition was found to be 73.7 +/- 6.9. In control groups where the animals were treated with Freund's complete adjuvant, yeast RNA and amoebal RNA treated with RNase, the percent leucocyte migration inhibition was 15.8 +/- 2.9, 16.8 +/- 6.2 and 14.0 +/- 4.0 respectively. Anti Eh RNA antibodies (haemagglutinins and precipitins) could not be demonstrated in immunized animals at any stage of observations. The cellular immunity could be maintained at its high level by giving three immunization doses of Eh RNA and also a high degree (95.45%) of protection against experimental challenge with virulent strain of E. histolytica could be obtained in immunized animals. The immunogenic and protective capabilities of Eh RNA were found to be specific since they were abolished by the RNase treatment. Further, the yeast RNA failed to elicit immunity.     

Anti-inflammatory activity of piperine

Piperine (1-peperoyl piperidine) was isolated from Piper nigrum Linn for the evaluation of anti-inflammatory activity in rats. Different acute and chronic experimental models like carrageenin-induced rat paw edema, cotton pellet granuloma, and croton oil-induced granuloma pouch, were employed. Simultaneously, biochemical estimations were made to elucidate the underlying mechanism of the action. Piperine acted significantly on early acute changes in inflammatory processes and chronic granulative changes. It also acted partially through stimulation of pituitary adrenal axis. Exudative changes in both acute and chronic models, however, were insignificant.     

alpha-Santonin 1,2-reductase and its role in the formation of dihydrosantonin and lumisantonin by Pseudomonas cichorii S

1,2-Dihydrosantonin is the first stable product in the degradative pathway of alpha-santonin by Pseudomonas cichorii S. Its formation is catalyzed by an oxidoreductase, which is NADH or NADPH dependent and has an apparent Km value of 66.66 microM for santonin and 44.33 microM for NADH. The enzyme activity is stable at pH 6.0, 7.0, and 8.0, and is not affected by EDTA and divalent metal ions. It is postulated that the enzymic reduction of santonin occurs via formation of a transient zwitterionic intermediate, which undergoes nonenzymatic 1,4-sigmatropic rearrangement to yield lumisantonin during the solvent extraction process. Lumisantonin is, thus, not a true metabolic intermediate but an artifact.     

Mitochondrial Complex I Impairment and Nitrate Reductase Activity in Leaves of Nicotiana sylvestris

Loss of major mitochondrial complex I subunit Nad 7 in the leaves of CMS II mutant of Nicotiana sylvestris caused increase in both in vivo and in vitro nitrate reductase activities and the per cent activation state of NR was also higher in CMS II as against wild type. The differences suggest a possibility for export of mitochondrial NADH due to impairment of complex I, a major and high affinity sink for NADH. Loss of complex I subunit also resulted in constitutive expression of alternate oxidase (Aox) thereby providing a mechanism for continuous supply of carbon skeletons required for nitrate assimilation. The possibility of close coordination between mitochondrial redox perturbation and nitrate reduction and its further assimilation is discussed.