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Li B.,South China University of Technology | Li B.,Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters | Wu P.,South China University of Technology | Wu P.,Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters | And 5 more authors.
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2014

Four kinds of layered double hydroxides (LDHs) were prepared by chemical coprecipitation method and used as DNA adsorbents. Multiple characterization tools such as power X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and Standard electronic modules (SEM) were employed to characterize the LDHs. By examining the effect of initial concentration, solution pH, adsorption experiments were carried out to investigate the adsorption capacities of LDHs for DNA. The results revealed that the LDHs with Mg/Al = 3 had higher ability on adsorbing the DNA and were not affected by pH values. The LDHs exhibited excellent adsorption properties and completely adsorbed DNA within 2 h. The adsorption equilibrium data were fitted to the Langmuir and Freundlich models, showing that the Langmuir model which represented monolayer adsorption had better correlation with the adsorption linear equation. In addition, Circular dichroism (CD) spectrum, UV-vis spectorscopy and agarose gel electrophoresis revealed the integrity of DNA structure, suggesting that there had no damage on the DNA structure during the adsorption process. © 2013 Elsevier B.V. All rights reserved. Source


Yang Y.,Fujian Agriculture and forestry University | Huang S.,Guangdong Regular Higher Education Institutions | Huang S.,South China University of Technology
Research Journal of Biotechnology | Year: 2014

Pure cultures of Chelatococcus daeguensis TAD1 were incubated at high temperature (50°C) using nitrate as a substrate and an electron acceptor for denitrification. The periplasmic nitrate reductase gene (napA), nitrite reductase gene (nirK), nitric oxide reductase gene (cnorB) and nitrous oxide reductase gene (nosZ) expression were measured using a quantitative reverse transcription-PCR at various initial dissolved oxygen (DO) concentrations. All the four genes expression reached a maximum at 12h. The maximum expression level of napA, nirK and nosZ was at 50rpm, the corresponding DO concentrations of which were 2.2 mg/l, but the maximum expression level of cnorB was at 150rpm, the corresponding DO concentrations of which were 2.6 mg/l. These results demonstrated that low dissolved oxygen conditions were more beneficial to expression of the denitrification genes in C. daeguensis TAD1 at high temperature. Source


Yang Y.,Fujian Agriculture and forestry University | Huang S.,Guangdong Regular Higher Education Institutions | Huang S.,South China University of Technology | Zhang Y.,Guangdong Regular Higher Education Institutions | Xu F.,Guangdong Regular Higher Education Institutions
Applied Biochemistry and Biotechnology | Year: 2014

Chelatococcus daeguensis TAD1 was demonstrated to be an aerobic denitrifier. It can utilize not only nitrate and nitrite but also ammonium at high temperature (about 50 C). The strain had the capability to remove 122.7 and 71.7 mg L-1 NH4 +-N by 18 h at 50 and 30 C, respectively. Triplicate heterotrophic nitrification experiments showed that 32.3 % of removed NH4 +-N was completely converted to nitrogen gas by 18 h at 50 C. The denitrification genes involved in C. daeguensis TAD1 were identified and sequenced. It was found that the genes responsible for denitrification in TAD1 were napA, nirK, cnorB, and nosZ. Taken together, TAD1 can be an effective candidate for simultaneous nitrification and denitrificaton at high temperature. © 2013 Springer Science+Business Media New York. Source


Liang K.-M.,South China Agricultural University | Liang K.-M.,Key Laboratory of Agro Environment in the Tropics | Zhang J.-E.,South China Agricultural University | Zhang J.-E.,Key Laboratory of Agro Environment in the Tropics | And 7 more authors.
Chinese Journal of Ecology | Year: 2013

A laboratory experiment was conducted to study the effects of mechanical stimulation on the physiological characters of rice plant. Mechanical stimulation decreased the permeability of rice leaf plasma membrane, but, with the increase of stimulation intensity and treatment time, the permeability presented an increasing trend. The leaf chlorophyll a (Chl-a) content was increased by mechanical stimulation treatments, while the leaf chlorophyll b (Chl-b) content presented a decreasing trend. Low intensity mechanical stimulation increased the activities of protective enzymes peroxidase (POD), superoxide dismutase (SOD), and polyphenol oxidase (PPO) in rice leaves. In mechanical stimulation treatments, the leaf 3-indoleacetic acid (IAA) content was reduced with time, whereas the leaf abscisic acid (ABA) content and the root activity showed an opposite trend. These results indicated that mechanical stimulation could be one of the important reasons leading to the morphological and physiological variations of rice plant. The findings from this study could provide a theoretical basis to further study the effects and action mechanisms of mechanical stimulation on the rice plant growth in rice-duck farming system. Source


Xiang Y.,South China University of Technology | Xiang Y.,The Key Laboratory of Pollution Control and Ecosystem Restoration | Wu P.,South China University of Technology | Wu P.,The Key Laboratory of Pollution Control and Ecosystem Restoration | And 13 more authors.
Journal of Hazardous Materials | Year: 2010

The objectives of this study were to evaluate the solubility of copper in waste printed circuit boards (PCBs) by bacterial consortium enriched from natural acid mine drainage, and to determine optimum conditions of bioleaching copper from PCBs. The results indicated that the extraction of copper was mainly accomplished indirectly through oxidation by ferric ions generated from ferrous ion oxidation bacteria. The initial pH and Fe2+ concentration played an important role in copper extraction and precipitate formation. The leaching rate of copper was generally higher at lower PCB powder dosage. Moreover, a two-step process was extremely necessary for bacterial growth and obtaining an appropriate Fe2+ oxidation rate; a suitable time when 6.25g/L of Fe2+ remained in the solution was suggested for adding PCB powder. The maximum leaching rate of copper was achieved 95% after 5 days under the conditions of initial pH 1.5, 9g/L of initial Fe2+, and 20g/L of PCB powder. All findings demonstrated that copper could be efficiently solubilized from waste PCBs by using bacterial consortium, and the leaching period was shortened remarkably from about 12 days to 5 days. © 2010 Elsevier B.V. Source

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