[Antibiotics Induce Horizontal Gene Transfer of Resistance at Sublethal Concentrations].

In order to explore the conjugation of genes encoding extended-spectrum -lactamase (ESBL), ESBL-expressing and strains isolated from the wastewater of major hospitals in Singapore were used as donors. gfp-tagged SCC1 strains resistant to chloramphenicol (CHL) were chosen as recipients. Using response surface analysis, we detected and analyzed the induction of conjugal transfer under single-exposure and co-exposure of tetracycline (TC), sulfamethoxazole (SMZ), and ceftazidime (CAZ) at sublethal concentrations.

[Influence of Antibiotics on the Denitrification Process of Antibiotic Resistant Denitrifying Bacteria and the Analysis of Microbial Community Structure].

The removal rate of some antibiotics in urban sewage by conventional treatment is low, which leads to an increase in antibiotic resistant bacteria in natural water environments. To reduce the ecological harm of antibiotics to the water in towns, a risk control technique for degradation of microantibiotics by the co-metabolism of antibiotic resistant denitrifying bacteria was proposed. Using sodium acetate as an electron donor and maintaining the concentration of ofloxacin (OFLX) at 1 μg·g, gradually increasing the dominant growth of antibiotic degradation bacteria, denitrifying bacteria (DnB), trace antibiotics and sodium acetate, and denitrifying bacteria (DnB) with the presence of sodium acetate and nitrogen elements were cultured.

[Coupled Cytotoxicity of C60 Nano-Crystal Particle with Cu2+ to the Mouse Peritoneal Macrophage RAW 264.7].

This work evaluated the cytotoxicity effect of nC60 nano-crystal particle associated with Cu2+ by using mouse peritoneal microphage RAW264. 7 as the test cell line. The results showed that when exposed to nC60 of 6.

[Phosphorus fractions, sorption characteristics and its release in the sediments of Yangtze Estuary Reservoir, China].

To analyze the sediment phosphorus (P) fractions and sorption characteristics and P release from sediment of reservoir in Yangtze estuary, the sediment was investigated during April, 2011 to January, 2012. Results of chemical fractionation analysis showed that total P (TP) content in sediment ranged from 535.07 to 910.

[Removal of nickel from aqueous solutions using complexation-ultrafiltration process].

Polyacrylate (PAANa) and polyethylenimine (PEI) were used as complexing agents to combine with nickel ions. This complexation solution was transferred to the ultrafiltration cell and the separation by polyethersulfone (PES) ultrafiltration membranes was carried out under the pressure of 0.1 MPa.

N2O and N2 production during heterotrophic nitrification by Alcaligenes faecalis strain NR.

A heterotrophic nitrifier, strain NR, was isolated from a membrane bioreactor. Strain NR was identified as Alcaligenes faecalis by Auto-Microbic system and 16S rRNA gene sequence analysis. A.

Reactions of tetracycline antibiotics with chlorine dioxide and free chlorine.

Tetracyclines (TCs) are a group of widely used antibiotics that have been frequently found in the aquatic environment. The potential reactions of TCs with common water disinfection oxidants such as chlorine dioxide (ClO(2)) and free available chlorine (FAC) have not been studied in depth and are the focus of this study. The oxidation kinetics of tetracycline, oxytetracycline, chlorotetracycline and iso-chlorotetracycline by ClO(2) and FAC are very rapid (with large apparent second-order rate constants k(app) = 2.

[Isolation and characterazation of a carbazole-degrading bacterial strain].

A bacterial strain was isolated from soil samples using plate screening techniques. Results indicated this isolated were able to use carbazole as sole source of carbon and energy, simultaneously, including N-Methylcarbazole, 4-Hydroxycarbazole and 2,2'-Biphenol. It was identified as Flavobacterium sp.

Oxidation of fluoroquinolone antibiotics and structurally related amines by chlorine dioxide: Reaction kinetics, product and pathway evaluation.

Fluoroquinolones (FQs) are a group of widely prescribed antibiotics and have been frequently detected in the aquatic environment. The reaction kinetics and transformation of seven FQs (ciprofloxacin (CIP), enrofloxacin (ENR), norfloxacin (NOR), ofloxacin (OFL), lomefloxacin (LOM), pipemidic acid (PIP) and flumequine (FLU)) and three structurally related amines (1-phenylpiperazine (PP), N-phenylmorpholine (PM) and 4-phenylpiperidine (PD)) toward chlorine dioxide (ClO(2)) were investigated to elucidate the behavior of FQs during ClO(2) disinfection processes. The reaction kinetics are highly pH-dependent, can be well described by a second-order kinetic model incorporating speciation of FQs, and follow the trend of OFL > ENR > CIP ∼ NOR ∼ LOM > > PIP in reactivity.

[Removal of lead from aqueous solutions by complexation-ultrafiltration with chitosan].

Polyethersulphone (PES) membrane was chosen and chitosan was used as complexing agent to remove lead ions by complexation-ultrafiltration. Effects of solution pH, Pb2+/chitosan ratio, ionic strength and Ca2+ on the rejection coefficient of lead were investigated. The effect of concentration time on lead rejection coefficient and membrane flux was also studied.

[Effect of charged ultrafiltration membrane on natural organic matter removal and membrane fouling].

With the deterioration of water pollution and stringency of water standards, ultrafiltration (UF) has become one of the best alternatives replacing conventional drinking water treatment technologies. However, UF is not very effectively to remove natural organic matter (NOM) due to the comparatively large pore size compared to the size of NOM. Fouling issue is another factor that restricts its widespread application.

[Comparison of the effect of solution environment on humic acid removal behavior with charged and traditional neutral ultrafiltration membranes].

Experiments were performed to evaluate the effect of solution environment (pH value, ionic strength and Ca2+) on humic acid removal and membrane fouling during filtration of humic acid through charge-modified regenerated (RC) ultrafiltration (UF) membrane and traditional unmodified neutral RC UF membrane. Results showed that: (1) the pH value changed the net charge on humic acid molecule and charged membrane through protonation effect, which further influenced the ultrafiltration behavior. When the solution pH value decreased from 7.

Nitrogen removal capability through simultaneous heterotrophic nitrification and aerobic denitrification by Bacillus sp. LY.

The heterotrophic nitrification and aerobic denitrification capabilities of Bacillus sp. LY were investigated under the aerobic condition. The results indicate that Bacillus sp.

Heterotrophic nitrogen removal by Providencia rettgeri strain YL.

Providencia rettgeri strain YL was found to be efficient in heterotrophic nitrogen removal under aerobic conditions. Maximum removal of NH(4) (+)-N occurred under the conditions of pH 7 and supplemented with glucose as the carbon source. Inorganic ions such as Mg(2+), Mn(2+), and Zn(2+) largely influenced the growth and nitrogen removal efficiency.

Heterotrophic nitrogen removal by a newly isolated Acinetobacter calcoaceticus HNR.

Strain HNR, isolated from a Membrane Bioreactor (MBR), demonstrates a surprising ability to convert ammonium to nitrogen gas under aerobic conditions while growing heterotrophically. On the basis of phylogenetic analysis of the 16S rRNA gene sequence, strain HNR was related to Acinetobacter calcoaceticus (98.9% identity).

[Characteristic and prospects of heterotrophic nitrification].

Nitrification is a key step in the global nitrogen cycle. Classically, nitrifying bacteria are chemoautotroph. Recently, bacteria that have the ability of heterotrophic nitrification have been intensively studied as potential microorganisms that may be used to overcomeproblems inherent in the conventional method.

The enthalpies of formation for polychlorinated dibenzofurans with use of G3XMP2 model chemistry and density functional theory.

The standard gas-phase enthalpies of formation of polychlorinated dibenzofurans (PCDFs) have been predicted by using G3XMP2 model chemistry, density functional theory (DFT), and second-order Muller-Plesset (MP2) theory, coupled with isodesmic reactions. The results show a large difference between G3XMP2 and DFT methods with 6-31G(2df,p) and 6-311++G(3df,3pd) basis sets, while MP2/G3MP2Large calculations agree closely with G3XMP2. Two isodesmic reaction schemes are used for better prediction of formation enthalpies.

[Effects of organic matters and temperature on the anaerobic biodegradation of nonylphenol polyethoxylates].

The biodegradation of nonylphenol polyethoxylates (NPEOs) was studied under three different reductive conditions (methanogenesis, denitrification, and desulfuration conditions). Effects of organic matter and temperature on the biodegradation of NPEOs were also studied. The results showed that NP9EO could be rapidly biodegraded under three different reductive conditions.

[Biodegradation of nonylphenol ethoxylates by a bacterial strain with heterotrophic nitrogen removal ability].

Biodegradation of nonylphenol ethoxylates (NPEOs) by Bacillus sp. LY with heterotrophic nitrogen removal ability was investigated. The study showed that Bacillus sp.

Isolation and characterization of a new heterotrophic nitrifying Bacillus sp. strain.

Objective: To characterize the heterotrophic nitrifying bacteria.

Methods: The bacteria were isolated from membrane bioreactor for treating synthetic wastewater using the method newly introduced in this study. Fluorescence in situ hybridization (FISH) was used to validate the nonexistence of autotrophic ammonia oxidizers and nitrite oxidizers.

[Biodegradation of toxic organic pollutants by Bacillus sp. LY with heterotrophic nitrogen removal ability].

Bacillus sp. LY, with heterotrophic nitrogen removal ability, can biodegrade many kinds of toxic organic pollutants. The study illuminates that Bacillus sp.

[Nitrogen removal by Bacillus sp. LY with heterotrophic nitrification ability].

Bacillus sp. LY has the ability of nitrogen removal. Under the NH4(+) -N load of 40, 80 and 120 mg/L, after 120 hours culture, the NH4(-) -N removal rate finally was 100%, 85.

[Biodegradation of 2, 4- and 2, 6-dinitrotoluene in a pilot-scale system for soil contaminated with explosive compounds].

A pilot-scale system consisting of a soil biodegradation tank, a denitrification tank, and a recirculating feeding tank was designed and applied to study the biodegradation of 2,4- and 2,6-dinitrotoluene in soil contaminated with the explosives. The experimental results showed that 2, 4- and 2, 6-DNT can be degraded completely by native DNT degrading bacteria existing in the contaminated soil, despite water temperatures as low as 8 degrees C to 15 degrees C. Compared to 2,4-DNT, the biodegradation of 2,6-DNT was much slower and took much longer time.

Isolation of a new heterotrophic nitrifying Bacillus sp. strain.

A heterotrophic nitrifier, named Bacillus sp. LY, was newly isolated from a membrane bioreactor (MBR). Bacillus sp.

[Study progress on the mechanism of heterotrophic nitrification].

Nitrification plays an important role in the nitrogen cycle. Autotrophic bacteria have traditionally been regarded as the nitrifying agents. However, research in last few decades has established that a lot of heterotrophic microorganisms also make contribution to nitrification.