Biosorption of lead and copper from aqueous solutions by pre-treated crab and arca shell biomass

Sorption potential of pretreated crab and arca shell biomass for lead and copper from aqueous media was explored. The effects of pH, initial concentration, biosorbent dosage and contact time were studied in batch experiments. Effects of common ions like sodium, potassium, calcium and magnesium on the sorption capacity of pretreated crab and arca biomasses were also studied. At equilibrium, the maximum uptake by crab shell biomass was 19.83+/-0.29 and 38.62+/-1.27 mg/g for lead and copper, respectively. In case of arca shell biomass the maximum uptake capacity was 18.33+/-0.44 mg/g and 17.64+/-0.31 mg/g for lead and copper, respectively. Combined effect of all the common ions up to 50 microg/ml concentration was negligible for both the metals using both biomasses. Sorption isotherms were studied to explain the removal mechanism of both elements by fitting isotherms data into Lagergren, Freundlich and Langmuir equations.     

Preliminary results on the photoluminescence and optically stimulated luminescence in Cu‐doped and Ag‐doped ZnB2X4 (B = Li,Na, K: X = Cl,Br) compounds

Photoluminescence, and optically stimulated luminescence in ZnB₂X₄ (B; Li,Na,K: X; Cl,Br) compounds doped with Cu⁺ or Ag⁺ were studied. Double humped emission bands attributable to the activators were observed in all the samples. The observed photoluminescence of Cu⁺ and Ag⁺ could be identified with 3d⁹4s¹?3d¹⁰ and 4d⁹5s¹?5d¹⁰ transitions respectively. The longer wavelength band (400–500 nm range) could be attributed to the Cu⁺ or Ag⁺ ion replacing alkali ion at the octahedral alkali site whereas short wavelength band (340–400 nm range) is attributed to a Cu or Ag ion at tetrahedral zinc site. The short wavelength band was found to be intense compared with long wavelength and gave an indication that most of the Cu or Ag ions prefered a tetrahedral Zn site compared with the octahedral alkali site. All the samples exhibit optically stimulated luminescence (OSL). The sensitivity was found to be lattice dependent. The lowest sensitivity of about 1% compared with Al₂O₃:C was observed in lithium lattices whereas highest the sensitivity of about 290% was observed in the case of Cu‐doped ZnNa₂Br₄.     

Genomic and physiological analyses of an indigenous strain, <Emphasis Type="Italic">Enterococcus faecium</Emphasis> 17OM39

The human gut microbiome plays a crucial role in human health and efforts need to be done for cultivation and characterisation of bacteria with potential health benefits. Here, we isolated a bacterium from a healthy Indian adult faeces and investigated its potential as probiotic. The cultured bacterial strain 17OM39 was identified as Enterococcus faecium by 16S rRNA gene sequencing. The strain 17OM39 exhibited tolerance to acidic pH, showed antimicrobial activity and displayed strong cell surface traits such as hydrophobicity and autoaggregation capacity. The strain was able to tolerate bile salts and showed bile salt hydrolytic (BSH) activity, exopolysaccharide production and adherence to human HT-29 cell line. Importantly, partial haemolytic activity was detected and the strain was susceptible to the human serum. Genomics investigation of strain 17OM39 revealed the presence of diverse genes encoding for proteolytic enzymes, stress response systems and the ability to produce essential amino acids, vitamins and antimicrobial compound Bacteriocin-A. No virulence factors and plasmids were found in this genome of the strain 17OM39. Collectively, these physiological and genomic features of 17OM39 confirm the potential of this strain as a candidate probiotic.     

A component of green tea, (-)-epigallocatechin-3-gallate, promotes apoptosis in T24 human bladder cancer cells via modulation of the PI3K/Akt pathway and Bcl-2 family proteins

Bladder cancer is the fourth most common cancer in men and ninth most common in women. It has a protracted course of progression and is thus an ideal candidate for chemoprevention strategies and trials. This study was conducted to evaluate the chemopreventive/antiproliferative potential of (-)-epigallocatechin gallate (EGCG, the major phytochemical in green tea) against bladder cancer and its mechanism of action. Using the T24 human bladder cancer cell line, we found that EGCG treatment caused dose- and time-dependent inhibition of cellular proliferation and cell viability, and induced apoptosis. Mechanistically, EGCG inhibits phosphatidylinositol 3'-kinase/Akt activation that, in turn, results in modulation of Bcl-2 family proteins, leading to enhanced apoptosis of T24 cells. These findings suggest that EGCG may be an important chemoprevention agent for the management of bladder cancer.