Prevalence of sibling-species of Anopheles (Cellia) fluviatilis complex in Himachal Pradesh, India.

BACKGROUND & OBJECTIVES: Malaria is one of the most infectious and life-threatening vector borne disease in the tropics. Climate change can significantly influence malaria epidemiology and expansion of malaria vectors to hilly regions of Himachal Pradesh in India, hitherto considered areas of low transmission. Entomological surveillance in Kangra district of Himachal Pradesh revealed high density of a proven efficient vector of malaria, Anopheles fluviatilis, but transmission intensity of malaria was found very low. It was therefore considered prudent to investigate the sibling-species composition of An. fluviatilis complex in Kangra valley to ascertain their role in transmission of malaria. METHODS: The study was undertaken in six villages in Kangra district of Himachal Pradesh, India. A total of 4446 mosquitoes were collected during the one-year study period (2018) and processed in pools of ten for molecular characterization. DNA extraction and multiplex PCR was performed on 900 An. fluviatilis mosquitoes for differentiation of sibling-species. ELISA was used to detect Plasmodium falciparum and Plasmodium vivax circumsporozoite proteins in 3790 An. fluviatilis samples. RESULTS: Among prevalent mosquito species, An. fluviatilis was the predominant species constituting 69.5% of total mosquito collection. Sibling-species U was found in 92.22% and species T in 7.78% samples assayed. ELISA confirmed the absence of evidence of malaria parasite in any of the An. fluviatilis mosquitoes screened. Based on the difference in the sequences of conserved regions of the 28SrDNA, sibling-species U was confirmed as prevalent in the study villages. INTERPRETATION & CONCLUSION: Study revealed that in Kangra district, An. fluviatilis sibling-species U is predominant followed by species T, and both are non-vectors. The absence of malaria parasite and zoophagic nature of An. fluviatilis established through blood meal analysis, confirmed that both U and T are non-vector sibling-species.

Toxic metals biosorption by Jatropha curcas deoiled cake: equilibrium and kinetic studies.

The equilibrium sorption of Cr(VI) and Cu(II) from aqueous solution using Jatropha curcas deoiled cake, has been studied with respect to adsorbent dosage, contact time, pH, and initial metal concentration in batch mode experiments. Removal of Cu(II) by deoiled cake was greater than that of Cr(VI). The adsorbent chemical characteristics, studied by Fourier transform-infrared analysis, suggested that the presence of Cr(VI) and Cu(II) in the biomass influenced the bands corresponding to hydroxyl and carboxyl groups. Desorption studies revealed that maximum metals recovery was achieved by HNO3 followed by CH3COOH and HCl. The Freundlich isotherm model showed good fit to the equilibrium adsorption data. The adsorption kinetics followed the pseudo-second-order model, which provided the best correlation for the biosorption process, and suggested that J. curcas deoiled cake can be used as an efficient biosorbent over other commonly used sorbents for decontamination of Cr(VI)- and Cu(II)-containing wastewater.

Cr(VI) sorption by free and immobilised chromate-reducing bacterial cells in PVA-alginate matrix: equilibrium isotherms and kinetic studies.

Chromate-resistant bacterial strain isolated from the soil of tannery was studied for Cr(VI) bioaccumulation in free and immobilised cells to evaluate its applicability in chromium removal from aqueous solution. Based on the comparative analysis of the 16S rRNA gene, and phenotypic and biochemical characterization, this strain was identified as Paenibacillus xylanilyticus MR12. Mechanism of Cr adsorption was also ascertained by chemical modifications of the bacterial biomass followed by Fourier transform infrared spectroscopy analysis of the cell wall constituents. The equilibrium biosorption analysed using isotherms (Langmuir, Freundlich and Dubinin-Redushkevich) and kinetics models (pseudo-first-order, second-order and Weber-Morris) revealed that the Langmuir model best correlated to experimental data, and Weber-Morris equation well described Cr(VI) biosorption kinetics. Polyvinyl alcohol alginate immobilised cells had the highest Cr(VI) removal efficiency than that of free cells and could also be reused four times for Cr(VI) removal. Complete reduction of chromate in simulated effluent containing Cu(2+), Mg(2+), Mn(2+) and Zn(2+) by immobilised cells, demonstrated potential applications of a novel immobilised bacterial strain MR12, as a vital bioresource in Cr(VI) bioremediation technology.

Bioligninolysis: recent updates for biotechnological solution.

Bioligninolysis involves living organisms and/or their products in degradation of lignin, which is highly resistant, plant-originated polymer having three-dimensional network of dimethoxylated (syringyl), monomethoxylated (guaiacyl), and non-methoxylated (p-hydroxyphenyl) phenylpropanoid and acetylated units. As a major repository of aromatic chemical structures on earth, lignin bears paramount significance for its removal owing to potential application of bioligninolytic systems in industrial production. Early reports illustrating the discovery and cloning of ligninolytic biocatalysts in fungi was truly a landmark in the field of enzymatic delignification. However, the enzymology for bacterial delignification is hitherto poorly understood. Moreover, the lignin-degrading bacterial genes are still unknown and need further exploration. This review deals with the current knowledge about ligninolytic enzyme families produced by fungi and bacteria, their mechanisms of action, and genetic regulation and reservations, which render them attractive candidates in biotechnological applications.