Time filter

Source Type

Deng L.,Chongqing University | Pan Y.,Chongqing University | Chen X.,Beijing Agro Biotechnology Research Center | Chen G.,Chongqing University | Hu Z.,Chongqing University
Plant Physiology and Biochemistry | Year: 2013

Homozygous state-associated co-suppression is not a very common phenomenon. In our experiments, two transgenic plants 3A29 and 1195A were constructed by being transformed with the constructs pBIN-353A and pBIN119A containing nptII gene as a marker respectively. The homozygous progeny from these two independent transgenic lines 3A29 and 1195A, displayed kanamycin-sensitivity and produced a short main root without any lateral roots as untransformed control (wild-type) seedlings when germinated on kanamycin media. For the seedlings derived from putative hemizygous plants, the percentage of the seedlings showing normal growth on kanamycin media was about 50% and lower than the expected percentage (75%). Southern analysis of the genomic DNA confirmed that the homozygous and hemizygous plants derived from the same lines contained the same multiple nptII transgenes, which were located on the same site of chromosome. Northern analysis suggested that the marker nptII gene was expressed in the primary and the hemizygous transformants, but it was silenced in the homozygous transgenic plants. Further Northern analysis indicated that antisense and sense small nptII-derived RNAs were present in the transgenic plants and the blotting signal of nptII-derived small RNA was much higher in the homozygous transgenic plants than that of hemizygous transgenic plants. Additionally, read-through transcripts from the TRAMP gene to the nptII gene were detected. These results suggest that the read-through transcripts may be involved in homozygous state-associated silencing of the nptII transgene in transgenic tomato plants and a certain threshold level of the nptII-derived small RNAs is required for the homozygous state-associated co-suppression of the nptII transgene. © 2013 Elsevier Masson SAS.

Liu J.,University of Science and Technology Beijing | Liu J.,Inner Mongolia University of Technology | Wang Q.,University of Science and Technology Beijing | Wang S.,University of Science and Technology Beijing | And 3 more authors.
Journal of Biotechnology | Year: 2013

Microwave-alkali and steam-alkali coupled pretreatments were carried out to improve the yield and optical purity of l-lactic acid produced using vinasse fermentation. Lactobacillus casei was inoculated into the system to initiate fermentation. Polymerase chain reaction denaturing gradient gel electrophoresis was used to analyze the microbial community during fermentation with and without the pretreatments. The original bacterial genus in vinasse was essentially inactivated, whereas L. casei became the dominant genus after 24. h of fermentation. The system subjected to microwave-alkali coupled pretreatment released more reducing sugars and produced more lactic acid (up to 30.32. g/L), which is twice that without pretreatment. In addition, the proportion of lactic acid in the organic acids also increased. The optical purity of the l-lactic acid produced under the microwave-alkali coupled pretreatment reached 91%, which is 2% higher than that under the steam-alkali coupled pretreatment and 7% higher than that under the control conditions. Therefore, the microwave-alkali coupled pretreatment is an effective method for the highly efficient bioconversion of vinasse into bioenergy. © 2012 Elsevier B.V.

Pan Y.,Chongqing University | Pan Y.,University of Nottingham | Seymour G.B.,University of Nottingham | Lu C.,University of Nottingham | And 3 more authors.
Plant Cell Reports | Year: 2012

A novel member of the AP2/ERF transcription factor family, SlERF5, was identified from a tomato mature leaf cDNA library screen. The complete DNA sequence of SlERF5 encodes a putative 244-amino acid DNA-binding protein which most likely acts as a transcriptional regulator and is a member of the ethylene responsive factor (ERF) superfamily. Analysis of the deduced SlERF5 protein sequence showed that it contained an ERF domain and belonged to the class III group of ERFs proteins. Expression of SlERF5 was induced by abiotic stress, such as high salinity, drought, flooding, wounding and cold temperatures. Over-expression of SlERF5 in transgenic tomato plants resulted in high tolerance to drought and salt stress and increased levels of relative water content compared with wild-type plants. This study indicates that SlERF5 is mainly involved in the responses to abiotic stress in tomato. © 2011 Springer-Verlag.

Zhang L.,Northeast Dianli University | Zhuang Y.,Northeast Dianli University | Wang X.,Beijing Agro Biotechnology Research Center | Zhang H.,Northeast Dianli University
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2016

It is well accepted that nitrogen and phosphorus are the predominant compounds for the promotion of algae growth, and the removal of nitrogen and phosphorus involved in the wastewater has received a world-wide attention. In the biological wastewater treatment process, temperature is one of the most important physical factors, which will influence the metabolic activity and growth of microorganisms and thus their conversion capabilities in the carbonaceous, nitrogen and phosphorus compounds. The effects of temperature variations on the removal efficiencies of chemical oxygen demand (COD), nitrogen and phosphorus were investigated with an anaerobic-aerobic-anoxic process (AOA) (i.e., modified A2/O process). Compared to the conventional anaerobic-anoxic-aerobic process (i.e., A2/O process), the modified A2/O process could utilize the internal carbon contained in poly-β-hydroxybutyric acid (PHB) of the phosphorus accumulation organisms (PAOs) as the carbon source in the anoxic stage for denitrification. The AOA process could avoid the problem induced by the lack of carbon source in denitrification and the completion of carbon source between microorganisms for nitrogen and phosphorus removal. Besides, the environmental conditions created under the AOA process could promote the reproduction and growth of the denitrifying phosphorus accumulation organisms (DPAOs). The effects of temperature variations on PHB degradation rate, NO3 --N reduction rate and phosphorus uptake rate were also discussed. Furthermore, the effects of temperature on the kinetics of anoxic metabolism were analyzed. The present research could provide theoretical guidance and technical supports for the engineering application of the simultaneous removal process of nitrogen and phosphorus. The results showed that temperature had a significant impact on the denitrifying phosphorus removal system. When the temperature declined from 12 to 9℃, the removal efficiency of COD declined from 86.76% to 81.19% and the removal efficiency of total nitrogen (TN) declined from 61.44% to 59.39%, whereas the change of the removal efficiency of PO4 3--P was slight. According to the performance tests with the denitrifying phosphorus removal sludge, too high or too low temperature could lead to the changes of phosphorus release and absorption rate. The rates of anaerobic phosphorus release, aerobic phosphorus uptake and anoxic phosphorus uptake reached the maximum values at 27℃ and were 7.38, 9.18 and 5.15 mg/(g·h), respectively. The temperature also had a great influence on the proportion of DPAOs in the activated sludge. When the temperature was 27℃, the ratio of DPAOs/PAOs reached its maximum value of 56.16%. The effects of temperature on phosphorus uptake rate, NO3 --N reduction rate and PHB degradation rate were quite remarkable in the denitrifying phosphorus removal process. When the temperature was 27℃, the rates of the phosphorus uptake, nitrate reduction and PHB oxidation were the highest, which were 5.15 mg/(g·h), 7.13 mg/(g·h) and 0.81 mmol/(g·h), respectively. By using the extended Arrhenius equation, the temperature kinetic coefficients of the anoxic stage were 1.120-1.164 and 1.137-1.153, respectively, which indicated that all the anoxic stoichiometry parameters were sensitive to temperature changes. In conclusion, in the field application, measures should be taken to maintain an appropriate temperature range in order to enhance the simultaneous removal of nitrogen and phosphorus. © 2016, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.

Hu Z.-L.,Chongqing University | Deng L.,Chongqing University | Yan B.,Chongqing University | Pan Y.,Chongqing University | And 4 more authors.
Biologia Plantarum | Year: 2011

The full-length cDNA of LeSGR1 was cloned from tomato by RT-PCR and RACE. The cDNA encoded a protein of 272 amino acid residues and was deposited in GenBank (accession No. DQ100158). Northern analysis suggests that LeSGR1 gene specifically expresses in senescent leaves and mature fruits of tomatoes. Desiccation and flooding induce the expression of LeSGR1 in tomato leaves and stems. Both in ethylene-insensitive mutants (Nr) and ripening inhibitor mutants (rin), the expression of LeSGR1 is markedly decreased compared with that in the wild type. Alignment of the nucleotide sequence of SGR1 cloned from the tomato green flesh (gf) mutant with that from the wild type tomato shows a single nucleotide change leading to an amino acid substitution in gf mutant. Furthermore, LeSGR1 gene silencing by RNA interference results in inhibited chlorophyll degradation similar to the phenotype in gf mutant. Thus, we conclude that LeSGR1 is crucial to chlorophyll degradation and the mutation of SGR1 protein might be responsible for gf tomato properties. © 2011 Springer Science+Business Media B.V.

Wang L.-H.,University of Science and Technology Beijing | Wang L.-H.,Handan College | Wang Q.,University of Science and Technology Beijing | Cai W.,University of Science and Technology Beijing | Sun X.,Beijing Agro Biotechnology Research Center
Biosystems Engineering | Year: 2012

The solid-state anaerobic co-digestion (AC) of distiller's grains (DG) and food waste (FW) for biogas production was investigated. The effects of different DG/FW (TS) ratios (10/1, 8/1, 6/1, 4/1, 1/0, and 0/1) were examined. Co-digestion with the above DG/FW ratios was found to be superior to that of mono-digestion. The AC of DG and FW had a good synergistic effect of the lower range of propionate/acetate ratio and VFA/alkalinity ratio. No methane was produced when the propionate/acetate ratio was >0.1 ± 0.01, but this inhibition was reversible. When the propionate/acetate ratio was <0.08 ± 0.01, methane production began to recover. When the volatile fatty acids (VFA)/alkalinity ratios were <0.9 ± 0.05, the AC of the influents successfully proceeded in a stable manner. However, when the VFA/alkalinity and propionate/acetate ratios were >1.25 ± 0.21 and 0.1 ± 0.01, respectively, the AC system reached an acidification crisis and failed. Therefore, the propionate/acetate and VFA/alkalinity ratios may be used as important indices for controlling anaerobic digestion (AD). © 2012 IAgrE.

Wang Y.,Beijing Agro Biotechnology Research Center | Wang H.,Beijing Agro Biotechnology Research Center | Li R.,Beijing Agro Biotechnology Research Center | Ma Y.,Hebei Normal University of Science and Technology | Wei J.,Beijing Agro Biotechnology Research Center
African Journal of Biotechnology | Year: 2011

A dehydrin gene, isolated from cDNA library established from the root of Populus euphratica, was determined from sequence analysis to be an SK2-type dehydrin (Pedhn). To investigate the function of Pedhn, it was expressed via the CaMV 35S promoter in transgenic Populus tremula × Populus alba. The Pedhn transgenic lines demonstrated higher water retention capacities in excised leaves of transgenic lines than that of wild type, and the rate of water loss in the leaves of transgenic lines were slower than that of wild type controls under drought stress. Higher water retention capacity and reduced water loss suggest that the transgenic lines would exhibit enhanced drought tolerance. Consistently, the seedlings of transgenic lines did have significantly enhanced drought tolerance when compared with that of the wild type controls under drought challenge, which indicated that expression of Pedhn could be used to genetically modify poplar to improve drought tolerance. © 2011 Academic Journals.

Zhang L.,Northeast Dianli University | Sun L.,Northeast Dianli University | Sun L.,Beijing Agro Biotechnology Research Center | Qiu T.,Beijing Agro Biotechnology Research Center | And 2 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2013

Solid-phase denitrification (SPD) process is characterized by insoluble biodegradable polymers used as carbon sources. It is likely to avoid the risk of overdosing of liquid carbon sources in the conventional with the resultant deterioration of the effluent water quality. SPD process has been successfully applied on the treatment of groundwater and wastewater with a low ratio of carbon to nitrogen. This work was carried out in order to predict the nitrate concentration in the treated water and optimize the parameters using SPD process. A laboratory scale reactor was used, which was packed with the poly (3-Hydroxybutyrate-co-3-Hydroxyvalerate) (PHBV) granules as both carbon source and biofilm carrier for nitrate removal from the contaminated water. Based on Box-Behnken experimental design, the relationship among the effluent and influent nitrate-nitrogen concentrations, temperature and hydraulic retention time (HRT) was quantitatively investigated using response surface methodology. The calculated values of the equation were agreed well with the experimentally tested data, and their relative errors ranged from 1.5% to 19%. This equation can quantitatively describe the relationship among the effluent and influent nitrate-nitrogen concentrations, temperature and HRT. Influent nitrate-nitrogen concentration, HRT, temperature and their interaction had significant impacts on the response value by analysis of variance (P<0.05).

Zhang L.-H.,Northeast Dianli University | Li D.-S.,Northeast Dianli University | Wang X.-M.,Beijing Agro Biotechnology Research Center | Zhang H.-F.,Northeast Dianli University
Huaxue Gongcheng/Chemical Engineering (China) | Year: 2015

A long-term continuous experiment was carried out using A2/O process in order to improve the efficiency of biological phosphorus removal system. The effects of different carbon sources (acetate, propionate and glucose) on the competition between polyphosphate-accumulating organisms (PAO) and glycogen-accumulating organisms (GAO) were investigated. The results show that when propionate is used as the sole carbon source, the changes of intracellular substances and the accumulated GAO in the activated sludge system are minimal, and the mass concentration of phosphorus released is 38.3 mg/L and removal efficiency of TP is 93.8%. When acetate is used as the sole carbon source, the mass concentrations of phosphorus released (55.7 mg/L) and PAO accumulated are respectively highest, and the removal efficiency of TP is 89.1%. When glucose is used as the sole carbon source, the accumulated concentration of GAO is maximal. However, the mass concentration of phosphorus released is the lowest (4.9 mg/L) and the removal efficiency of TP is also minimal (57.5%). The acetate and propionate are utilized easily as an energy source by the PAO and PAO becomes the dominant species. The glucose is utilized easily as an energy source by GAO and GAO becomes the dominant species. © 2015, Editorial Office of Chemical Engineering (China). All right reserved.

PubMed | Beijing Agro Biotechnology Research Center
Type: Journal Article | Journal: Huan jing ke xue= Huanjing kexue | Year: 2013

Polylactic acid/Poly (3-Hydroxybutyrate-co-3-Hydroxyvalerate) (PLA/PHBV) granules were used as both carbon source and biofilm carrier for nitrate removal from the contaminated water. The polymerase chain reaction-denature gradient gel electrophoresis (PCR-DGGE) was used to investigate the dynamic change of microbial community in the biofilm coating onto PLA/PHBV granules. The results showed that a decrease in microbial diversity was observed at the initial stage of reactor operation. Shannon-Wiener and Simpson diversity indexes of microbial community in the biofilm slightly changed during the stable period of the reactor running. The major microorganisms in the biofilm were Gram-negative rod bacteria including the genera of Diaphorobacter, Acidovorax, Rubrivivax, Azospira, Thermomonas and Devosia, and all of them belonged to alpha-, beta- and gamma- Proteobacteria, according to the SEM photo of biofilm and 16S rDNA sequences of the DGGE profile. Moreover, the abundance of Diaphorobacter-like genera was the highest in the solid-phase-denitrification biofilm.

Loading Beijing Agro Biotechnology Research Center collaborators
Loading Beijing Agro Biotechnology Research Center collaborators