A CpxR-Regulated zapD Gene Involved in Biofilm Formation of Uropathogenic Proteus mirabilis.

Proteus mirabilis, a frequent uropathogen, forms extensive biofilms on catheters that are infamously difficult to treat. To explore the mechanisms of biofilm formation by P. mirabilis, we performed in vivo transposon mutagenesis. A mutant with impaired biofilm formation was isolated. The mutant was found to have Tn5 inserted in the zapD gene, encoding an outer membrane protein of the putative type 1 secretion system ZapBCD. zapBCD and its upstream zapA gene, encoding a protease, constitute an operon under the control of CpxR, a two-component regulator. The cpxR mutant and zapA mutant strains also had a biofilm-forming defect. CpxR positively regulates the promoter activities of zapABCD, cpxP, and cpxR An electrophoretic mobility shift assay revealed that CpxR binds zapA promoter DNA. The loss of zapD reduced CpxR-regulated gene expression of cpxR, zapA, cpxP, and mrpA, the mannose-resistant Proteus-like (MR/P) fimbrial major subunit gene. The restoration of biofilm formation in the zapD mutant with a CpxR-expressing plasmid reinforces the idea that CpxR-mediated gene expression contributes to zapD-involved biofilm formation. In trans expression of zapBCD from a zapBCD-expressing plasmid also reestablished the biofilm formation ability of the cpxR mutant to a certain level. The zapD and cpxR mutants had significantly lower protease activity, adhesion, and autoaggregation ability and production of exopolysaccharides and extracellular DNA (eDNA) than did the wild type. Finally, we identified copper as a signal for CpxR to increase biofilm formation. The loss of cpxR or zapD abolished the copper-mediated biofilm upshift. CpxR was required for copper-induced expression of zapA and cpxR Taken together, these data highlight the important role of CpxR-regulated zapD in biofilm formation and the underlying mechanisms in P. mirabilis.

[Vertical Pollution Characteristics and Sources of Polycyclic Aromatic Hydrocarbons in a Heterogeneous Unsaturated Zone Under a Coking Plant].

Six deep sampling boreholes are used for studying the sources and vertical distribution of 16 polycyclic aromatic hydrocarbons (PAHs) in an abandoned coking plant. The maximum depth of soil sampling ranged from 9.5-42 m. The present study analyzes the distribution characteristics and sources of PAHs in addition to the important factors affecting migration of PAHs in the unsaturated zone. Results showed that the maximum values of total PAHs range of 134.79-11266.81 mg·kg-1 at vertical depths ranging from 1-5 m. We found that 2+3 rings dominated total PAHs and that the highest content was Nap. Results also showed that the main source of PAH pollution was coal combustion. Coal tar pitch and different oils from deep processing of tar played an important role in PAH pollution. The gravel layer served as a good infiltration channel for pollutants, and the sand lens below 20 m depth became the main enrichment layer for PAHs through adsorption and interception. Oils and wastewater from discharge and leaching of chemicals contributed to the migration of PAHs through inter-miscibility and competitive adsorption, which led to deep soil pollution. Soil layers above 1 m depth were affected by artificial disturbance, rainfall leaching, and degradation, and the unsaturated zone below 30 m depth was affected by leaching from groundwater. Consequently, the ratio of low to high rings first increased before decreasing with increased depth of the unsaturated zone. The types of pollution sources, rock particle sizes, organic matter content, and hydrogeological conditions all affected the vertical distribution and migration of PAHs.

Association of polymorphisms in tektin-t gene with idiopathic asthenozoospermia in Sichuan, China.

PURPOSE: The purpose of this research was to study the association between the single nucleotide polymorphisms (SNPs) of the tektin-t gene and idiopathic asthenozoospermia. METHODS: We conducted sequence analyses of the tektin-t gene in 104 idiopathic asthenozoospermia and 102 fertile men with normospermic parameters in Sichuan, China. RESULTS: In this study, we found that allele 136 T (odds ratio [OR] 1.745, 95 % confidence interval [CI] 1.146-2.655, P = 0.009) was significantly increased in idiopathic asthenozoospermic patients compared with fertile men. This mutation substitutes a highly conserved arginine at position 46 to cysteine. Moreover, PolyPhen-2 analysis predicted that this variant was "probably damaging". In addition, a novel heterozygous mutation, R207H (c.620G >A), was detected in five asthenozoospermic patients, while there was no detection of this genotype among the fertile candidates, indicating that the mutation was located within a conserved domain predicted by PolyPhen-2 analysis as "probably damaging" to the protein. CONCLUSIONS: These results suggested that tektin-t variants (Arg/Cys + Cys/Cys) were probably one of the high risk genetic factors for idiopathic asthenozoospermia among males in Sichuan, China, while the R207H polymorphism may be associated with idiopathic asthenozoospermia risk.

Microscopic Fluorescence Spectral Characteristics of Mixing Ratio of Crude Oil Experiment.

The microscopic fluorescence spectroscopy has become a mature technology of fluid inclusions test and analysis system, which is used to distinguish different types of crude oil and oil inclusions. These would be the important basis to study the history of hydrocarbon accumulation of petroleum basins. The mixture of crude oil from different sources could occur in migration and accumulation process. In order to effectively identify the type of geological process, mixing ratio of crude oil experiment has been carried out. This study result shows that mixing of crude oil make fluorescence color and spectral parameters(λmax, QF535 and CIE-XY) change nonlinearly. Fluorescence spectral parameters of mixed oil is between end member oil A and B. The greater A or B ratio of mixed oil, the closer to A or B. Fluorescence color of mixed oil show nonlinear and gradual change in CIE-XY chromaticity diagram. Variation of spectral spectrum shape show that single peak is changed into double and three peaks. The relationship between QF535 and degree of mixing could calculate quantitatively relative contribution. Mixing different types of crude oil make spectral spectrum shape changes, which present characteristics of two peaks and three peaks but not unimodal peak. The main and subsidiary wavelength reserve wavelength information of end member oils. Based on variation characteristics of fluorescence spectrum, there are three different types of oil including blue, blue-green and yellow fluorescing oil filling in the bottom member of Pinghu formation in A gas field. At the same time, there also was a mixing process of blue-green fluorescing oil and yellow fluorescing oil. The degree of mixing is 47%~55%.

[Secondary Alterations Influence on Fluorescence Color and Spectral Parameters of Crude Oil and Oil Inclusion].

Based on oil samples and rock samples in several petroliferous basins, this paper studied that secondary alterations influence on fluorescence color and spectral parameters of crude oil and oil inclusions by using microscopic fluorescent spectral and geochemical parameters. The results demonstrated that secondary alterations influence on spectral parameters by changing the ratio of saturated hydrocarbon and aromatic hydrocarbon (saturation/aromatics). Biodegradation and water washing lead to redshift of fluorescence parameters while evaporative fractionation and oil cracking lead to blueshift. Beside, mixed oil lead to redshift and blueshift. The secondary alterations and main period of accumulation in research area were recognized by frequency histogram of crude oil and oil inclusion. The relationship between QF-535 and the parameters measuring the secondary alterations could the extent of secondary alterations from which crude oil suffered. In the microscopic fluorescence test, oil inclusions suffered from stretch or leakage, thermal cracking and photooxidation should be rejected.

Association of polymorphisms in glutathione S-transferase genes (GSTM1, GSTT1, GSTP1) with idiopathic azoospermia or oligospermia in Sichuan, China.

The reported effects of the glutathione S-transferase (GSTs) genes (GSTM1, GSTT1, and GSTP1) on male factor infertility have been inconsistent and even contradictory. Here, we conducted a case-control study to investigate the association between functionally important polymorphisms in GST genes and idiopathic male infertility. The study group consisted of 361 men with idiopathic azoospermia, 118 men with idiopathic oligospermia, and 234 age-matched healthy fertile male controls. Genomic DNA was extracted from the peripheral blood, and analyzed by polymerase chain reaction and restriction fragment length polymorphism analysis. There was a significant association between the GSTP1 variant genotype (Ile/Val + Val/Val) with idiopathic infertility risk (odds ratio [OR]: 1.53; 95% confidence interval [CI]: 1.11-2.11; P = 0.009). Similarly, a higher risk of infertility was noted in individuals carrying a genotype combination of GSTT1-null and GSTP1 (Ile/Val + Val/Val) (OR: 2.17; 95% CI: 1.43-3.31; P = 0.0002). These results suggest an increased risk of the GSTP1 variant genotype (Ile/Val + Val/Val) for developing male factor infertility. Our findings also underrate the significance of the effect of GSTM1 and/or GSTT1 (especially the former) in modulating the risk of male infertility in males from Sichuan, Southwest China.

[Perchlorate removal from underground water by anaerobic biological reduction with bark].

Batch experiments were conducted to check the feasibility of perchlorate removal from underground water with bark as a carbon source and reaction media, the effect of bark dosage, temperature and initial perchlorate concentrations on perchlorate reduction were also investigated. The results indicated that compared to corn cob, sweet potato and potato, bark in combination with perchlorate reducing microorganisms (PRMs) can efficiently achieve perchlorate removal from underground water, the concentrations of dissolved organic carbon (DOC) which was available to PRMs was the limiting factor that affected the perchlorate removal efficiency. Degradation of 10 mg perchlorate needed to consume 35-40 mg DOC when using bark as the solid carbon source. The removal rate of perchlorate was increased by about 3 fold when the bark dosage was increased from 1:500 to 3:500; however, further increase of solid-liquid ratio (over 5:500) provided no further benefit to the perchlorate reduction rate. The rate constant reached 1.365 mg x (L x d)(-1) at (38 +/- 1) degrees C which was the highest in the batch experiments. The activation energy was 31.08 kJ x mol(-1). Anaerobic biological reduction supported by bark had a good impact on the water quality; the high perchlorate concentration did not cause substrate inhibition.

Predicting mixture toxicity of seven phenolic compounds with similar and dissimilar action mechanisms to Vibrio qinghaiensis sp.nov.Q67.

The predictions of mixture toxicity for chemicals are commonly based on two models: concentration addition (CA) and independent action (IA). Whether the CA and IA can predict mixture toxicity of phenolic compounds with similar and dissimilar action mechanisms was studied. The mixture toxicity was predicted on the basis of the concentration-response data of individual compounds. Test mixtures at different concentration ratios and concentration levels were designed using two methods. The results showed that the Weibull function fit well with the concentration-response data of all the components and their mixtures, with all relative coefficients (Rs) greater than 0.99 and root mean squared errors (RMSEs) less than 0.04. The predicted values from CA and IA models conformed to observed values of the mixtures. Therefore, it can be concluded that both CA and IA can predict reliable results for the mixture toxicity of the phenolic compounds with similar and dissimilar action mechanisms.

Profile of organochlorine pesticides in soil cores from some hotspot areas of Beijing, China.

For the valid use of urban land and the safety of public health, an extensive contamination survey of organochlorine pesticides from five soil cores was conducted in the highly urbanized areas of Beijing in China. For topsoils in five soil cores, level of ∑HCHs and ∑DDTs varied from 0.174 to 4,783 ng g(-1) and 0.62 to 57,849 ng g(-1), respectively. The profile in topsoil of cores displayed that levels of pollutants in four soil cores from the urban areas with dense population are higher than that from outskirts. The depth characteristics of pollutants indicated that the level of ∑HCHs and ∑DDTs in BY and WU was close to/below the background value of soil in China (50 ng g(-1)), but those in some soil samples from A, B and ZX core, especially A and B, was above the threshold value for the soil safety (1,000 ng g(-1)). In views of the usage history of the land and profiles of contaminants, the source in A and B probably came from the dumped waste chemical materials in the old chemical factories. The study of soil cores sampled revealed the existence of chemical "time bomb" in urban regions of Beijing. Also, the finding indicated the absolute necessity of assessing the soil quality with the unprecedented land use changes in the big city community.

[Effects of benzene, toluene on reductive dechlorination of trichloroethylene and its daughter product cis-1,2-dichloroethylene by granular iron].

Mixed plumes contained chlorinated solvents and petroleum hydrocarbons which mainly refers to BTEX (benzene, toluene, ethylbenzene and xylenes) in groundwater can be remediated by sequential units combined an iron permeable reactive barrier (Fe0-PRB) with an anoxic wall. In design of the Fe0-PRB it should be taken into account the necessity of altering the width of the iron cell in the presence of BTEX. Three column experiments were conducted to evaluate the effects of benzene, toluene on the long-term performance of reductive dechlorination of trichloroethylene (TCE) by granular iron. The results showed that the kinetics of TCE (at the initial concentration of 2 mg x L(-1) more or less) reduction was accorded with pseudo first-order even in the presence of benzene or toluene (at about 1-2 mg x L(-1), respectively). The existence of benzene and toluene inhibited the removal of TCE by 15.1% and 18. 5% , respectively; however, the presence of benzene slightly increased cis-1,2-DCE reduction rate by 4.5%, and the presence of toluene increased cis-1,2-DCE reduction rate by 42.8%. The inhibition of benzene and toluene other than mineral precipitates was not one of the decisive factors in the long-term performance of an Feo-PRB; in addition, the kinds of chlorinated daughter products of TCE in the presence/absence of benzene or toluene were identical and cis-1,2-dichloroethylene (cis-1,2-DCE), the major intermediate, firstly broke through from all the 3 columns at concentrations about 2-75 microg x L(-1), indicating that designing the width of an Fe0-PRB should be based on the hydraulic residence time of cis-1,2-DCE. In conclusion, if only considering the TCE remedial goals and disregarding the effects of cis-1,2-DCE on BTEX biodegradation downgradient the Fe0-PRB, the results suggested that it should be not necessary to increase the width of the iron cell for constructing sequential permeable reactive barriers (SPRBs) to rescue TCE- and BTEX-contaminated aquifers.

[Contamination characteristics and pollutant sources analysis on PAHs in shallow groundwater in suburb of Taihu plain].

To investigate shallow groundwater quality in Taihu plain, south of Jiangsu province, 56 samples were collected in north area (C area), north east area (W area) and east area (S area). The concentrations of priority 16 polycyclic aromatic hydrocarbons (PAHs) were analyzed by HP 6890-GC. Hierarchical cluster analysis (HCA) and Molecular ratios were used to characterize their possible pollution sources. Concentrations of total priority 16 PAHs in shallow groundwater samples ranged from below method detection limits (< MDLs) to 32.45 microg/L with the average value of 4.42 microg/L, which were predominated by three and four-ring PAHs. High contents of PAHs were found in the vicinity of industrial areas. Ratios of specific PAH compounds including phenanthrene/anthracene (Phe/Ant), fluoranthene/pyrene (FL/Pyr), chrysene/ benzo(a)/anthracene (Chr/BaA), low-molecular-weight PAH/high-molecular-weight PAH (LPAH/HPAH) were calculated to evaluate the possible sources of PAH contamination. These ratios reflected a mixed pattern of pyrolytic and petrogenic inputs of PAHs with different proportion in shallow groundwater. Hierarchical cluster analysis (HCA) results showed that the abnormal benzo (k) fluoranthene concentration dominated the HCA results in C area, the abnormal benzo(a)anthracene concentration dominated the HCA results in W area, and the abnormal benzo (b) fluoranthene concertration dominated the HCA results in S area. At level 0.05, FL, AcPy, Acp, Phe and Bap in C area had Pearson correlation between 0.680 and 0.712. BP, BaA and Bap in W area had Pearson correlation between 0.724 and 0.773. AcPy and Flu in S area had Pearson correlation 0.659, which meant that these PAHs listed in each areas might came from the same kind of sources.

[Chlorinate solvents natural biodegradation in shallow groundwater].

Chlorinated solvents contaminations are most popular in shallow groundwater. A serious local groundwater contamination of chlorinated solvents is founded in a north city of China during the organic pollution investigation. On the basis of the available data and the determining methods of chlorinated solvents biodegradation in groundwater under natural conditions, research on chlorinated solvents biodegrading potential is carried out. The results show that the ground water environment parameters, Eh and pH of the groundwater, indirect sign of biodegradation, i.e. NO3- changing, and concentration variation of biodegradation intermediate products of PCE and TCE all proved that chlorinated solvents can be degraded by microorganism in groundwater. The results of simulating experiment also reveal that, co-metabolism biodegradation of chlorinated solvent was possible under the groundwater circumstances in this sample. Therefore, admitting there is biotransformation from PCE to TCE can explain the present situation more reasonably.

Hydrocarbon charging histories of the Ordovician reservoir in the Tahe oil field, Tarim Basin, China.

The Ordovician reservoir of the Tahe oil field went through many tectonic reconstructions, and was characterized by multiple hydrocarbon chargings. The aim of this study was to unravel the complex charging histories. Systematic analysis of fluid inclusions was employed to complete the investigation. Fluorescence observation of oil inclusions under UV light, and microthermometry of both oil and aqueous inclusions in 105 core samples taken from the Ordovician reservoir indicated that the Ordovician reservoir underwent four oil chargings and a gas charging. The hydrocarbon chargings occurred at the late Hercynian, the Indo-Sinian and Yanshan, the early Himalaya, the middle Himalaya, and the late Himalaya, respectively. The critical hydrocarbon charging time was at the late Hercynian.