[Adsorption Mechanisms of Ciprofloxacin by Extracellular Polymeric Substances of Sulfate-reducing Bacteria Sludge].

Extracellular polymeric substances (EPS) in microbial sludge, fulfils a key role in removal of micro-organic pollutants during biological wastewater treatment. In this study, the authors evaluated the removal of ciprofloxacin (CIP) by sulfate-reducing bacteria (SRB) sludge in a sulfate-reducing up-flow sludge bed (SRUSB) reactor, and examined the role of EPS on CIP removal in an SRB sludge system. The results indicated that CIP was removed efficiently through adsorption and biodegradation by SRB sludge, with adsorption the major removal pathway. EPS also played an important role in CIP adsorption by SRB sludge, and the adsorption mechanisms of CIP by EPS were investigated using the three-dimensional excitation-emission matrix fluorescence spectroscopy technologies combined with parallel factor analysis. The functional groups binding CIP onto EPS were identified through Fourier transform infrared (FTIR) spectra analysis. The results suggested that the static quenching of EPS following CIP adsorption led to formation of an EPS-CIP complex, and that the CIP was mainly bound with tryptophan and tyrosine-like protein substances in EPS with the binding constants of 1.43×104 L·mol-1 and 1.02×104 L·mol-1, respectively. The FTIR results suggested that hydroxyl, amino and carboxyl functional groups were mainly responsible for binding of CIP onto EPS. The results revealed the adsorption mechanisms of CIP by EPS in SRB sludge, and enhanced understanding of the role of EPS in sulfur-mediated biological processes for the removal of CIP and other organic micro-pollutants.

Multiple genetic variants are associated with colorectal cancer risk in the Han Chinese population.

Colorectal cancer (CRC) is a major health burden worldwide and is the second-leading cause of cancer-related death in Europe. CRC is a complex disease resulting from a series of genetic and epigenetic changes that lead to a stepwise progression from normal mucosa to dysplasia and finally to carcinoma. In this study, we present genetic association results between 25 tag single-nucleotide polymorphisms and CRC in a case-control study (203 cases, 296 controls) of a Han Chinese population. We found that rs1143634 in the interleukin-1ß (IL1B) gene and rs1800871 in the interleukin-10 (IL10) gene were associated with increased risk for CRC in the Han Chinese. Further haplotype analysis revealed that the 'GAC' in the SMAD7 (mothers against decapentaplegic homolog 7) gene was found to increase CRC risk (odds ratio=1.48; 95% confidence interval, 1.09-2.01; P=0.012). Our results, combined with previous studies, suggest that IL10, PSCA, IL1B, and SMAD7 are significantly correlated with CRC susceptibility in the Han Chinese population.