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Yi Qian

Publications and source records attributed to Yi Qian.

At least 19 recordsLinked to original sources
PubMed2006

Interdomain interactions in the tumor suppressor discs large regulate binding to the synaptic protein GukHolder.

Multidomain scaffolding proteins are central components of many signaling pathways and are commonly found at membrane specializations. Here we have shown that multiple interdomain interactions in the scaffold Discs Large (Dlg) regulate binding to the synaptic protein GukHolder (GukH). GukH binds the Src homology 3 (SH3) and guanylate kinase-like (GK) protein interaction domains of Dlg, whereas an intramolecular interaction between the two domains inhibits association with GukH. Regulation occurs through a PDZ domain adjacent to the SH3 that allows GukH to interact with the composite SH3-GK binding site, but PDZ ligands inhibit GukH binding such that Dlg forms mutually exclusive PDZ ligand and GukH cellular complexes. The PDZ-SH3-GK module is a common feature of membrane associate guanylate kinase scaffolds such as Dlg, and these results indicate that its supramodular architecture leads to regulation of Dlg complexes.

Amino Acid Sequence↗
PubMed2006

Excess sludge reduction induced by Tubifex tubifex in a recycled sludge reactor.

Sludge reduction in a conventional activated sludge (CAS) process combined with a recycled sludge reactor where Tubifex tubifex (one of Oligochaeta) was inoculated was investigated in this study. The results showed sludge production could be reduced through T. tubifex's predation on sludge in the recycled sludge reactor. The sludge reduction rate of T. tubifex (R) was from 0.18 to 0.81 mg-VSS mg-Tubifex(-1) d(-1). The sludge reduction capacity of the recycled sludge reactor E was from 650 to 1080 mg-VSS L(-1) d(-1). The optimum density of T. tubifex was 2500 mg L(-1) and the optimum sludge recycled ratio was 1. The existence of T. tubifex did not affect COD and NH(4)(+)-N removals in the process, but led to a slight decrease in TP removal. SVI almost did not change when the T. tubifex density was lower than 3300 mg L(-1). The LC50 values on T. tubifex of copper and ammonia were 2.5 and 880 mg L(-1), respectively, both of which were higher than those on Aeolosoma hemprichi.

Ammonia↗
PubMed2006

In situ bioelectrokinetic remediation of phenol-contaminated soil by use of an electrode matrix and a rotational operation mode.

In situ bioremediation is a safe and cost-effective technology for the cleanup of contaminated sites, but its remediation rate is usually very slow. This study attempted to accelerate the process of bioremediation by employing non-uniform electrokinetic transport processes to mix organic pollutants and degrading bacteria in soils under in situ conditions (namely, in situ bioelectrokinetic remediation) by use of an electrode matrix and a rotational operation mode. A bench-scale non-uniform electrokinetic system with periodic polarity-reversal was developed for this purpose, and tested by using a sandy loam spiked with phenol as a model organic pollutant. The results demonstrated that non-uniform electrokinetic processes could enhance the in situ biodegradation of phenol in the soil, the efficiency of which depended upon the operational mode of the electric field. Compared with the unidirectional operation and the bidirectional operation, the rotational operation could effectively stimulate the biodegradation of phenol in the soil if adopting appropriate time intervals of polarity-reversal and electrode matrixes. A reversal interval of 3.0 h and a square-shaped electrode matrix with four electrode couples appeared appropriate for the in situ biodegradation of phenol, at which a maximum phenol removal of 58% was achieved in 10d and the bioremediation rate was increased about five times as compared to that with no electric field applied. The results also showed that adopting a small polarity-reversal interval and an appropriate electrode array could produce a high and uniform removal of phenol from the soil. It is believed that in situ bioelectrokinetic remediation holds the potential for field application.

Biodegradation, Environmental↗
PubMed2006

[Conjugation and immunogenic evaluation of complete immunogen for the small molecular environmental pollutants 2,4-D].

Conjugation of complete immunogen for 2,4-dichlorophenoxyacetic acid (2,4-D) was studied. 2,4-D was cross-linked to bovine serum albumin (BSA, carrier) by 1-ethyl-3-(3-dimethyl- aminopropyl) carbodiimide hydrochloride (EDC). The conjugation reaction was found to be more effective at 4 degrees C and incubated for 18 hour. 2,4-D was dissolved in 0.05 mol/L phosphate buffer between 10.0 - 12.0 mg/mL concentration, pH was adjusted to be 5.4 - 6.1. When the weight of added EDC was below 12 mg, the more EDC was added the higher substitution degree complete immunogen was synthesized. Complete immunogen of various substitution degree (2,4-D: protein) were applied to immunize balb/c mice. The conjugates of 2,4-D and poly-L-lysine was applied as coating antigen. It was experimentally found that complete immunogen of substitution degree 12 and 18 are more immunogenic than that of substitution degree 6 and 25. None-specific adsorption between antiserum that was produced by complete immunogen of substitution degree 18 and coating antigen was very weak, and the antiserum contained more 2,4-D specific antibody. It could be used as the immunogen for the preparation monoclonal antibody.

2,4-Dichlorophenoxyacetic Acid↗
PubMed2006

[Production of ligninolytic enzymes in bioreactor].

Production of ligninolytic enzymes under nitrogen limited conditions(C/N = 56/2.2) was studied in a 5-L stirred tank bioreactor with a working volume of 2 L for obtaining higher production of ligninolytic enzymes by white rot fungus Phanerochaete chrysosporium BKM-F-1767 and its control strategy. Results show that the manganese peroxidase (MnP) and laccase (Lac) reached peak at the sixth day and the seventh day, respectively, and the variation of them with time in a batch cultivation are similar to the results by agitated Erlenmeyer flasks; however higher enzyme activity was not achieved by applying a fed-batch strategy, in which nitrogen limited medium was fed to the reactor. In addition, variation of pH during cultivation was related to the growth of P. chrysosporium and enzymes production during both batch and fed-batch cultivation. The pH value of liquid medium began to decline when the enzyme activity occurred in the system, and the decline became more and more slow along with the decrease of enzyme activity at the end of fermentation. So, pH would be as a control parameter to find out the growth of P. chrysosporium and enzymes production during incubating P. chrysosporium. However, fed-batch strategy still need further study.

Biofilms↗
PubMed2006

[Preparation of polyclonal antibody against microcystin-LR].

Good quality polyclonal antibody against Microcystin-LR (MC-LR) was obtained from the New Zealand rabbit immunized with the homemade complete antigen BSA-MC-LR. Indirect ELISA shows the titer of this antibody is more than 1.5 x 10(5); Indirect competitive ELISA immobilized the coating antigen OVA-MC-LR was adapted to detect MCs, the calibration curve shows that the detection lower limit is 10 ng/L, and the range of quantitative detection was between 30 ng/L to 3 microg/L, with a good linearity, which will well potentially suit for sensitive analysis for MC-LR in drinking as well as surface water samples.

Antibodies, Bacterial↗
PubMed2006

[Detection of SRPs in injection water of Shenli Oil Field by FISH].

Fluorescence in situ hybridization (FISH) with 16S rRNA-targeted oligonucleotide probes was applied for analyzing the structure of sulfate reducing prokaryotes (SRPs) community in injection water of Shengli Oil Field. Eight probes and their various combinations were used to detect SRPs in the water. Results showed SRPs detected in the water were diverse, which followed in 4 bacterial phyla and 1 archaeal phylum. Total amount of SRPs was 2.86 x 10(4) cells/mL, accounting for 20% of total cells of microorganisms in the water of the Oil Field. Desulfovibrio and Desulfotomaculum cells were about 8.71% (+/- 4.45%) and 12.15% (+/- 3.90%) of the total microbial cells respectively, being dominant in the water. The relative amounts of SRPs belonging to Desulfobacterales and Syntrophobacterales, Thermodesulfobacteriales, and Thermodesulfovibro to total microbial cells in the water were 7.59% (+/- 2.92%), 3.57% (+/- 1.39%) and 2.32% (+/- 0.80%) respectively. In addition, SRPs belonging to Archaeoglobus were also detected with the amount of 4.29% (+/- 1.75%) of total microbial cells, which tells that archeal SRPs are also very important sulfate reducing microorganisms in the injection water of oil field.

Archaea↗
PubMed2006

[Detection of microcystin-LR in waters using indirect competitive ELISA].

Indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) was established to detect microcystin-LR in waters, with the concentration of the complete antigen was 5microg/mL, the dilution of the monoclonal antibody was 1:3,000, the dilution of the enzyme tracer (goat anti-rabbit IgG-peroxidase) was 1:3,000, the concentration range of microcystin-LR was between 0.001 approximately 30microg/L, and using o-phenylenediamine as substrate. The assay showed a high relativity of more than 99% with high performance liquid chromatography, a mean relative standard deviation less than 10% , a detection limitation under 0.01microg/L and quantitative detection range was 0.01 approximately 3microg/L, high specificity for [4-arginine] microcystin, and it could still perform well under the influence from the samples.

Antibodies, Monoclonal↗
PubMed2006

[Approaches for increasing the culturability of microorganisms].

Only a tiny amount of microorganisms on the earth can be cultured so far, which seriously obstructs the investigation into principles of microbial activities and exploiting microbial resources. To improve the culturing methods and to develop novel culturing techniques is therefore very important to increase the culturabilty of microorganisms and to isolate more uncultured microorganisms, which is of crucial importance to research principles of microbial life, to understand the interaction between microbial cells for correctly designing, applying and manipulating environmental microbial processes. This review systematically summarized the causes for microorganisms' unculturability and recent work on the approaches to increase the culturability of microorganisms. To mimic natural environment (physically, chemically and biologically) and to introduce microbial interactions into culture medium as many as possible is suggested to be of key importance to increase culturability of microorganisms.

Biomimetics↗
PubMed2006

[Effect of trace element on the growth of white rot fungus and suppressing yeast in liquid medium].

Growth of white rot fungus in liquid medium with different trace element and effect of these medium on suppressing the growth of yeast under non-sterile were investigated in agitated Erlenmeyer flasks. Results showed that the size and amount of mycelium pellets in liquid medium with trace element and Fe 3.5 mg/L was more than that with trace element but no iron and without any trace element under sterile condition; moreover, the size and amount of mycelium pellets increased with the rise of the concentration of trace element and iron. In addition, if applying the mode of incubating under sterile condition and degrading under non-sterile condition, the decolorization of reactive brilliant red K-2BP in liquid medium without any trace element and with trace element but no iron was similar to that of degrading under sterile condition; but the decolorization in liquid medium with trace element and Fe 3.5 mg/L was less than the results under sterile condition. Through observing under microscope, it was found that the amount of yeast in liquid medium with Fe 3.5 mg/L was more than the medium without any trace element and with trace element but no iron. Therefore, trace element, especially iron, plays a very important role in suppressing yeast in liquid medium; furthermore, iron also is necessary to the growth of whit rot fungus. So that, to control the concentration of iron in liquid medium could reduce the invasion of yeast under non-sterile condition as long as it does influence the growth of white rot fungus.

Azo Compounds↗
PubMed2005

Determination and comparison of sludge reduction rates caused by microfaunas' predation.

Using micorfauna to reduce excess sludge is a potentially effective ecological technology and scaling the rate of sludge reduction rate is the first step. A method to scale the rate of sludge reduction caused by microfauna was proposed, and comparison of sludge reduction rates induced by four microfaunas was carried out. The principle of this method is based on the change of carbon forms. The rate of sludge reduction was correlated with the rate at which solids were changed into liquid and gas. Four microfaunas, including Aeolosoma hemprichi, Daphnia magna, Tubifex tubifex and Physa acuta, were cultured with sterilized sludge in a covered sterilized bottle and were then isolated from the atmosphere above the liquid phase. The rates of sludge reduction using the four microfaunas were 0.8, 0.18, 0.54 and 0.1 mg-sludge/(mg-Microfauna d), respectively, changing with the microfaunas' phylum or class and body size. Based on the change of carbon (C) forms, the proposed method produced accurate results similar to those produced using the direct measuring method.

Animals↗
PubMed2005

The use of non-uniform electrokinetics to enhance in situ bioremediation of phenol-contaminated soil.

In situ bioremediation is an attractive and often cost-effective technology for the cleanup of organics-contaminated sites, but it often requires extended treatment time under field conditions. This study explored the feasibility of using non-uniform electrokinetic transport processes to enhance in situ bioremediation. A bench-scale non-uniform electrokinetic system with periodic polarity-reversal was developed for this purpose, and tested by using a sandy loam spiked with phenol as a model organic pollutant. The results demonstrated that non-uniform electrokinetic processes could accelerate the movement and in situ biodegradation of phenol in the soil. Bidirectional operation enhanced the phenol biodegradation more effectively than unidirectional operation. At the same time, a smaller polarity-reversing interval induced a higher and more uniform removal of phenol from the soil. The results also showed that reversing the polarity of electric field applied could maintain the soil pH and moisture, but it increased the consumption of electricity.

Biodegradation, Environmental↗
PubMed2005

Mobilization of phenol and dichlorophenol in unsaturated soils by non-uniform electrokinetics.

The poor mobility of organic pollutants in contaminated sites frequently results in slow remediation processes. Organics, especially hydrophobic compounds, are generally retained strongly in soil matrix as a result of sorption, sequestration, or even formation into non-aqueous-phase liquids and their mobility is thus greatly reduced. The objective of this study was to evaluate the feasibility of using non-uniform electrokinetic transport processes to enhance the mobility of organic pollutants in unsaturated soils with no injection reagents. Phenol and 2,4-dichlorophenol (2,4-DCP), and kaolin and a natural sandy loam soil were selected as model organics and soils, respectively. The results showed that non-uniform electrokinetics can accelerate the desorption and movement of phenol and 2,4-DCP in unsaturated soils. Electromigration and electroosmotic flow were the main driving forces, and their role in the mobilization of phenol and 2,4-DCP varied with soil pH. The movement of 2,4-DCP in the sandy loam towards the anode (about 1.0 cmd(-1)V(-1)) was 1.0-1.5 cmd(-1)V(-1) slower than that in the kaolin soil, but about 0.5 cmd(-1)V(-1) greater than that of phenol in the sandy loam. When the sandy loam was adjusted to pH 9.3, the movement of phenol and 2,4-DCP towards the anode was about twice and five times faster than that at pH 7.7, respectively. The results also demonstrated that the movement of phenol and 2,4-DCP in soils can be easily controlled by regulating the operational mode of electric field. It is believed that non-uniform electrokinetics has the potential for practical application to in situ remediation of organics-contaminated sites.

Adsorption↗
PubMed2005

Effect of direct electric current on the cell surface properties of phenol-degrading bacteria.

The change in cell surface properties in the presence of electric currents is of critical concern when the potential to manipulate bacterial movement with electric fields is evaluated. In this study, the effects of different direct electric currents on the cell surface properties involved in bacterial adhesion were investigated by using a mixed phenol-degrading bacterial culture in the exponential growth phase. The traits investigated were surface hydrophobicity (measured by adherence to n-octane), net surface electrostatic charge (determined by measurement of the zeta potential), and the cell surface shape and polymers (determined by scanning electron microscope analysis). The results showed that a lower current (less than 20 mA) induced no significant changes in the surface properties of phenol-degrading bacteria, that an electric current of 20 mA could increase the surface hydrophobicity and flatten the cell shape, and that a higher current (40 mA) could increase the surface extracellular substances and the net negative surface electrostatic charge. The results also revealed that the electric current effects on cell hydrophobicity varied with the suspending medium. We suggest that an electric current greater than 20 mA is not suitable for use in manipulation of the movement of the phenol-degrading bacteria, although such a current might favor the electrophoretic movement of the bacterial species.

Bacteria↗
PubMed2005

Effect of salinity variations on the performance of activated sludge system.

OBJECTIVE: To investigate the influence of salinity variations on the performance of activated sludge systems, treating domestic wastewater. METHODS: The completely mixed reactor was used and operated in a batch-wise mode. The activated sludge taken from the Gaobeidian Wastewater Treatment Plant was used as a seeding sludge. Total organic carbon (TOC), oxygen uptake rate (OUR) and suspended solids (SS) were used as parameters to characterize the performance of the treatment systems. TOC was measured using a TOC-analyzer (TOC-5000, Japan). The OUR value was measured with a dissolved oxygen meter (YSI model-58). SS was measured gravimetrically. RESULTS: The TOC removal efficiency and the OUR value of activated sludge were not deteriorated when the NaCl shock concentration was less than 0.5 g/L. However, when the NaCl shock concentrations were up to 10g/L and 20 g/L, the OUR of activated sludge was reduced by 35% and TOC removal efficiency was dropped by 30%, compared with the control experiment without NaCl shock loading. CONCLUSION: The effect of NaCl shock loading on the activated sludge wastewater treatment system is dependant upon the NaCl concentrations and the degree of influence can be inferred through the change of substrate utilization rate at different shock NaCl loadings.

Bioreactors↗
PubMed2005

[Synthesis of complete antigen of microcystin-LR and its antibody production].

Based on the analysis of coupling location, coupling regent, carrying protein and coupling process, completed antigen of Microcystin-LR (MC-LR) was synthesized. A free amidogen was introduced to microcystin-LR (MC-LR) using chemical modification (aminoethylation) of its 7th core amino acids, N-methyl-dehydroalanine. The intermediate product Aminoethyl-MC-LR (H2N-etMC-LR) was purified by Solid Phase Elute (SPE) and identified by Mass Spectrometry, then coupled with BSA through glutaraldehyde to be complete antigen. The completed antigen was dialyzed and identified by SDS-PAGE, UV-scanning and bio-mass spectrometry. The result show that the coupling ratio between MC-LR and BSA of complete antigen in average was over 5, and it is sufficient to immunity.

Antibodies↗
PubMed2005

[Metabolic properties of the microbial community in the biofilters using biolog microplates].

It is very important to know the structure and metabolic function of the microbial community in a bioreactor in order to improve its performance. In this study, two biofilters, packed with wood chips and granular activated carbons respectively, were operated for 160 days to treat toluene gas. The metabolic profiles of the microbial communities in the biofilters were monitored using Biolog microplates periodically during the experiments. The metabolic activities of the microorganisms in both biofilters were observed to decrease during long-term operation. According to the results of principle components analysis, the metabolic profiles of the microbial communities did not change much in the former period of the operation, but they changed in the inlet layers on day 103 and changed throughout the filter beds on day 160. The variation of the metabolic profiles in both biofilters showed little difference, which suggested that the packing media had little effect on them during long-term operation. Among the 95 carbon sources in Biolog microplate, carboxylic acids and amino acids were much easier to be utilized by the microorganisms in the biofilters than the other carbon

Air Pollutants↗