Phospholipids fatty acids of drinking water reservoir sedimentary microbial community: Structure and function responses to hydrostatic pressure and other physico-chemical properties.

Microbial communities in three drinking water reservoirs, with different depth in Xi'an city, were quantified by phospholipids fatty acids analysis and multivariate statistical analysis was employed to interpret their response to different hydrostatic pressure and other physico-chemical properties of sediment and overlying water. Principle component analyses of sediment characteristics parameters showed that hydrostatic pressure was the most important effect factor to differentiate the overlying water quality from three drinking water reservoirs from each other. NH4+ content in overlying water was positive by related to hydrostatic pressure, while DO in water-sediment interface and sediment OC in sediment were negative by related with it. Three drinking water reservoir sediments were characterized by microbial communities dominated by common and facultative anaerobic Gram-positive bacteria, as well as, by sulfur oxidizing bacteria. Hydrostatic pressure and physico-chemical properties of sediments (such as sediment OC, sediment TN and sediment TP) were important effect factors to microbial community structure, especially hydrostatic pressure. It is also suggested that high hydrostatic pressure and low dissolved oxygen concentration stimulated Gram-positive and sulfate-reducing bacteria (SRB) bacterial population in drinking water reservoir sediment. This research supplied a successful application of phospholipids fatty acids and multivariate analysis to investigate microbial community composition response to different environmental factors. Thus, few physico-chemical factors can be used to estimate composition microbial of community as reflected by phospholipids fatty acids, which is difficult to detect.

Mechanism studies on chlorine and potassium permanganate degradation of microcystin-LR in water using high-performance liquid chromatography tandem mass spectrometry.

The presence of microystins (MCs) in water has the potential to harm people's health. In the MCs various isomers, MC-LR has the strongest toxicity and is the most harmful one. At present, several kinds of pre-oxidants, which are commonly used in water treatment process, are effective to remove MC-LR. However, it is still not clear about their degeneration mechanisms. Chlorine and potassium permanganate were selected in the present work since they are used worldwide for preoxidation treatment. Using the testing method of HPLC-MS, studies on the degeneration of MC-LR were conducted. The results indicate that HPLC-MS is creditable and sensitive. It was also found that linear relationship between concentration of MC-LR and peak area holds in the range of 5-500 microg.L(-1) on the calibration curves, the correlation coefficient (R2) is 0.9993. Under the general condition of oxidant dose and reaction time, MC-LR was degraded rapidly. With active chlorine and potassium permanganate the degradation reaction followed the mode of first-order kinetics. The molecular weight of the degradation product was determined through analyzing the full-scan mass spectrum of MC-LR. And the oxidative degradation mechanism of MC-LR was discussed as well.

Microbial effects on phosphorus release in aquatic sediments.

Microbial effects on phosphorus release were studied for the sediments of Tianjin source water by controlling DO and pH. The results show that: (1) In sterilised water, phosphorus began to release when pH = 9.1 and the stable release rate was 9.51 mg/(d.m2). It indicates that microorganisms may utilise anaerobic iron respiration to release Fe-P. (2) With unsterilised water, phosphorus release rate is 2.14 mg/(d.m2) when pH = 6.5, 8.60 mg/(d.m2) when pH is uncontrolled, and gets to 8.51 mg/(d.m2) when pH = 9.1. This indicates that microorganisms can dissolve insoluble phosphates to accelerate the ion exchange of OH(-) and PO4(3-), which are derived from iron-bound ortho-P and aluminium-bound ortho-P.

The effects of maternal cigarette smoking on pregnancy outcomes using assisted reproduction technologies: An updated meta-analysis.

There is strong evidence indicating that smoking has negative effects on female reproductive health. Studies to investigate the effects of female smoking on IVF outcomes have been conducted by several research groups, yet the results are controversial. To evaluate the impacts of female smoking on the outcomes of assisted reproduction, a meta-analysis was performed, which included studies published in English up to September 6, 2017 from the MEDLINE, EMBASE, and Cochrane library databases. Twenty-eight studies encompassing 5009 female smokers seeking assisted reproduction and 10,078 non-smokers were used in this meta-analysis. Significant negative outcomes were detected in the female smokers compared with non-smokers including decreases in live birth rate per cycle (OR=0.52, 95% CI 0.37-0.74), in clinical pregnancy rate per cycle (OR 0.59, 95% CI 0.51-0.68), in number of retrieved oocytes (MD=-0.87, 95% CI -1.39 to -0.25), and in average fertilization rate (MD=-4.80, 95% CI -8.49 to -2.02), as well as a significantly increased miscarriage rate per pregnancy (OR=2.48, 95% CI 1.79-3.43). In conclusion, the current meta-analysis provides compelling evidence that female smoking has a significantly negative impact on the outcomes of assisted reproductive technology (ART) and strongly recommends that female smokers will greatly benefit from a smoking cessation before employing ART to become pregnant.