Sustainable mitigation of heavy metals from effluents: Toxicity and fate with recent technological advancements.

Increase in anthropogenic activities due to rapid industrialization had caused an elevation in heavy metal contamination of aquatic and terrestrial ecosystems. These pollutants have detrimental effects on human and environmental health. The majority of these pollutants are carcinogenic, neurotoxic, and are very poisonous even at very low concentrations. Contamination caused by heavy metals has become a global concern for which the traditional treatment approaches lack in providing a cost-effective and eco-friendly solution. Therefore, the use of microorganisms and plants to reduce the free available heavy metal present in the environment has become the most acceptable method by researchers. Also, in microbial- and phyto-remediation the redox reaction shifts the valence which makes these metals less toxic. In addition to this, the use of biochar as a remediation tool has provided a sustainable solution that needs further investigations toward its implementation on a larger scale. Enzymes secreted by microbes and whole microbial cell are considered an eco-efficient biocatalyst for mitigation of heavy metals from contaminated sites. To the best of our knowledge there is very less literature available covering remediation of heavy metals aspect along with the sensors used for detection of heavy metals. Systematic management should be implemented to overcome the technical and practical limitations in the use of these bioremediation techniques. The knowledge gaps have been identified in terms of its limitation and possible future directions have been discussed.

Removal of methylene blue dye using rice husk, cow dung and sludge biochar: Characterization, application, and kinetic studies.

The present studies aimed for the removal of Methylene blue (MB) dye using the rice husk biochar (RHB), cow dung biochar (CDB) and domestic sludge biochar (SB) synthesized through slow pyrolysis at 500 °C. The biochar was used for the adsorption of synthetic aqueous MB dye. The removal efficiencies of MB by CDB, RHB and SB in a batch experiment were 97.0-99.0; 71.0-99.0 and 73.0-98.9% at conditions, pH (2.0-11.0); Biochar dosage (0.5-6.0 g/100 mL) for 5 days. Adsorption isotherm of Langmuir constant (KL) were obtained 0.101, 0.583 and 0.128 for RHB, CDB and SB respectively. Further, adsorption kinetics of pseudo first order for RHB, CDB and SB were 0.068, 0.018, and 0.066 while it was 0.031, 0.023 and 0.273 for pseudo second order kinetics. Thus, CDB was more effective adsorbent for the dye removal. The pHz values were 7.8, 6.3 and 6.0 for the CDB, RHB, and SB, respectively.

A critical review on exploiting the pharmaceutical potential of plant endophytic fungi.

The escalating demand for secondary metabolites in international markets poses a severe threat to many plant species. An unscrupulous collection is also the immediate challenge to the survival of many unthreatened as well as vulnerable plants. Fungal endophytes have emerged in recent years as a promising substitute for sources of plant secondary metabolites. Many appealing secondary metabolites with potent antibacterial, antifungal, insecticidal, antioxidant, cytotoxic and anticancer properties have been discovered from endophytic fungi. Concerning their distinctive genetic and metabolic diversity and promising activities, they hold a plausible application in medicine and industry. However, there is little success in utilizing the pharmaceutical potential of fungal endophytes. Cutting-edge research is desirable to establish and bolster in vitro biosynthetic proficiency of fungal endophytes. Modern biotechnological techniques [such as multilocus sequence typing (MLST), metabolomics, metagenomics and next-generation sequencing (NGS) technologies] and bioinformatics approaches can fill a gap in fungal endophyte research. The present review focuses on how advanced chemical, biotechnological and computational molecular biology methods can be used for robust exploitation of bioactive compounds from these microorganisms.

Determination and quantification of asiaticoside in endophytic fungus from Centella asiatica (L.) Urban.

Centella asiatica (L.) Urban is a highly considered medicinal plant owing to its secondary metabolites asiaticoside, madecassoside, asiatic acid, and madecassic acid. The asiaticoside, one of the most important constituents of the plant, is a triterpenoid saponin having memory enhancement property. Given its medicinal properties, we isolated and characterized endophytic fungi from this plant with the aim to screen these microorganisms for asiaticoside production. In total, we isolated 13 endophytic fungi from the leaves of the plant, out of which one of the isolates produced asiaticoside. This asiaticoside producing isolate was identified as Colletotrichum gloeosporioides by internal transcribed spacer-based rDNA sequencing. The presence of asiaticoside in ethyl acetate extract of C. gloeosporioides was confirmed by LC-MS. The production of asiaticoside measured in relation to incubation time and subculture generation revealed presence of 62.29 ± 3.36 µg/100 mL of asiaticoside by C. gloeosporioides on the 15th day in first subculture generation followed by a decrease in subsequent generations. A similar trend was also shown by yield and growth curve of C. gloeosporioides. The asiaticoside production and yield were found to be positively correlated. This paper reported the production of asiaticoside by an endophytic fungus C. gloeosporioides for the first time. The present findings definitely provide an impetus to the production of asiaticoside by utilizing the endophytic source. Chemical compound studied in this article: Asiaticoside (PubChemCID: 108062).

Molecular Characterization and In Silico Analysis of Defensin From Tor putitora (Hamilton).

Antimicrobial peptides (AMPs) are vital constituents of innate immune system. In fish, one of the most important AMP is ß-defensin that has a potential to activate the adaptive immune system. ß-defensin is a cysteine-arginine-rich cationic AMP with broad spectrum activity against microbes. In this study, we identified cloned and characterized ß-defensin 1 from Tor putitora, a cold water fish species also known as mahseer. An open reading frame of ß-defensin 1 was amplified, cloned and sequenced which encodes a peptide of 67 amino acid residues. The pro-peptide includes a signal peptide comprising 24 amino acids as predicted by Signal P along with a mature peptide of 43 amino acid residues. Tor putitora ß-defensin 1 (TP-ßdf1) has a molecular weight of 4.6 kDa with a pI of 8.35. Six cysteine residues are present in the mature peptide which is a characteristic feature of defensins. All six cysteine residues are involved in the formation of three intra-molecular disulfide bonds. Three-dimensional modeling of mature peptide of TP-ßdf1 was carried out using Modeller 9.10, and validated TP-ßdf1 model revealed three ß-sheets. The cysteine residues form three disulfide bonds in the pattern of Cys(1)-Cys(5), Cys(2)-Cys(4), Cys(3)-Cys(6) stabilizing the ß-sheet. Structural analysis revealed three ß-strands and an α-helix at the N terminus. Phylogenetic analysis revealed that the ß-defensin 1 of Tor putitora was close to Megalobrama amblycephala which possibly suggests that TP-ßdf1 peptide sequence is quite similar to ß-defensin peptide sequences of carps and minnows.

Characterization and structural analysis of hepcidin like antimicrobial peptide from Schizothorax richardsonii (Gray).

Innate immune system is a primary line of defense in fish that protects it from the invading pathogens. Antimicrobial peptides (AMPs) are widely distributed in nature and are essential components of innate immunity. These molecules enable the host's innate immune system to fight against a variety of infectious agents. One such AMP, hepcidin, is a cysteine rich amphipathic peptide. We have amplified, cloned and characterized hepcidin like AMP from Schizothorax richardsonii that inhabits one of the most difficult aquatic ecosystems in the Indian Himalayas. The cDNA encoding hepcidin like peptide was amplified as a 371 bp fragment with an open reading frame (ORF) of 279 nucleotides flanked by 5' and 3' UTRs of 70 and 22 bases respectively. This ORF encodes a peptide of 93 amino acids with a signal peptide of 24 amino acids and a mature peptide of 25 amino acids. The mature hepcidin like peptide of S. richardsonii has eight cystine residues that participate in the formation of four disulfide bonds, a unique feature of hepcidin like AMPs. A 3D model of hepcidin like mature peptide was generated using Modeller 9.10 which was validated using PROCHECK and ERRAT. Phylogenetic analysis of hepcidin like AMP from S. richardsonii revealed that it was closely related to hepcidin from olive barb (Puntius sarana).

Marinomonas polaris sp. nov., a psychrohalotolerant strain isolated from coastal sea water off the subantarctic Kerguelen islands.

Two aerobic, psychrohalotolerant, motile bacterial isolates, CK13T and CK16, isolated from sea-water samples collected off the subantarctic Kerguelen island, were characterized by using a polyphasic taxonomic approach. On the basis of 16S rRNA gene sequence data, the strains were 99.6% similar and exhibited 93-97% similarity with the seven recognized species of Marinomonas. The most closely related species were Marinomonas pontica and Marinomonas primoryensis, with 97 and 96 % similarity at the 16S rRNA gene sequence level, respectively. DNA-DNA hybridization values between strain CK13T and M. pontica and M. primoryensis were only 58 and 40%, respectively. The major fatty acids present in strain CK13T were iso-C(16:0), C(16:0), C(16:1)omega7c and C(18:1)omega7c. The DNA G+C content of strain CK13T was 41.2 mol%. Phosphatidylethanolamine and phosphatidylglycerol were identified as the predominant phospholipids. All the above characteristics support the affiliation of strain CK13T to the genus Marinomonas. Phylogenetic analysis and phenotypic and genotypic distinctiveness confirmed that strains CK13T and CK16 are members of a novel species of the genus Marinomonas, for which the name Marinomonas polaris sp. nov. is proposed. The type strain is CK13T (=MTCC 6645T=DSM 16579T=JCM 12522T).