We found a novel lipase gene in the Paenibacillus pasadenensis CS0611 strain.The lipase gene sequence was cloned into the pET-28a expression vector to construct a recombinant lipase protein containing 6×His tags ...We found a novel lipase gene in the Paenibacillus pasadenensis CS0611 strain.The lipase gene sequence was cloned into the pET-28a expression vector to construct a recombinant lipase protein containing 6×His tags at the C-and N-termini,respectively.High-level expression of the lipase in E.coli BL21(DE3)was obtained upon induction with IPTG at 20°C.The recombinant lipase activity was approximately 1631-fold higher than the wild type.His-tagged recombinant lipase was purified rapidly and efficiently by using Ni-charged affinity chromatography with 63.5%recovery and a purification factor of 10.78.The purified lipase was stable in a broad range of temperatures and pH values,with the optimal temperature and pH being 50°C and 7.0,respectively.Its activity was stimulated to different degrees in the presence of metal ions such as Ca2+,Mg2+,and some non-ionic surfactants.In addition,the purified lipase was activated by a series of water-miscible organic solvents such as some short carbon chain alcohols and was highly tolerant to some water-immiscible organic solvents.展开更多
Terrain referenced navigation estimates an aircraft navigation status by utilizing a radar altimeter measuring a distance between the aircraft and terrain elevation. Accurate digital elevation map is essential to esti...Terrain referenced navigation estimates an aircraft navigation status by utilizing a radar altimeter measuring a distance between the aircraft and terrain elevation. Accurate digital elevation map is essential to estimate the aircraft states correctly. However, the elevation map cannot represent the real terrain perfectly and there exists map error between the estimated and the true maps. In this paper, an influence of the map error on measurement equation is analyzed and a technique to incorporate the error in the filter is proposed. The map error is divided into two sources, accuracy error and resolution error. The effectiveness of the suggested technique is verified by simulation results. The method modifies a sensor noise covariance only so there is no additional computational burden from the conventional filter.展开更多
Aluminum(Al)is the most abundant metal element in the earth’s crust.On acid soils,at pH 5.5 or lower,part of insoluble Al-containing minerals become solubilized into soil solution,with resultant highly toxic effects ...Aluminum(Al)is the most abundant metal element in the earth’s crust.On acid soils,at pH 5.5 or lower,part of insoluble Al-containing minerals become solubilized into soil solution,with resultant highly toxic effects on plant growth and development.Nevertheless,some plants have developed Al-tolerance mechanisms that enable them to counteract this Al toxicity.One such well-documented mechanism is the Al-induced secretion of organic acid anions,including citrate,malate,and oxalate,from plant roots.Once secreted,these anions chelate external Al ions,thus protecting the secreting plant from Al toxicity.Genes encoding the citrate and malate transporters responsible for secretion have been identified and characterized,and accumulating evidence indicates that regulation of the expression of these transporter genes is critical for plant Al tolerance.In this review,we outline the recent history of research into plant Al-tolerance mechanisms,with special emphasis on the physiology of Al-induced secretion of organic acid anions from plant roots.In particular,we summarize the identification of genes encoding organic acid transporters and review current understanding of genes regulating organic acid secretion.We also discuss the possible signaling pathways regulating the expression of organic acid transporter genes.展开更多
We constructed an expression cassette of the organophosphorus pesticide degrading （opal） gene under the control of the E8 promoter. Then opd was transformed into tomato fruit using an agroinfiltration transient expr...We constructed an expression cassette of the organophosphorus pesticide degrading （opal） gene under the control of the E8 promoter. Then opd was transformed into tomato fruit using an agroinfiltration transient expression system. β-Glucuronidase （GUS） staining, reverse transcription-polymerase chain reaction （RT-PCR）, wavelength scanning, and fluorescent reaction were performed to examine the expression of the opd gene and the hydrolysis activity on coumaphos of organo- phosphorus hydrolase （OPH） in tomato fruit. The results show that the agroinfiltrated tomato fruit-expressed OPH had the maximum hydrolysis activity of about 11.59 Uhng total soluble protein. These results will allow us to focus on breeding transgenic plants that could not only enhance the degrading capability of fruit and but also hold no negative effects on pest control when spraying organophosphorus pesticides onto the seedlings in fields.展开更多
文摘We found a novel lipase gene in the Paenibacillus pasadenensis CS0611 strain.The lipase gene sequence was cloned into the pET-28a expression vector to construct a recombinant lipase protein containing 6×His tags at the C-and N-termini,respectively.High-level expression of the lipase in E.coli BL21(DE3)was obtained upon induction with IPTG at 20°C.The recombinant lipase activity was approximately 1631-fold higher than the wild type.His-tagged recombinant lipase was purified rapidly and efficiently by using Ni-charged affinity chromatography with 63.5%recovery and a purification factor of 10.78.The purified lipase was stable in a broad range of temperatures and pH values,with the optimal temperature and pH being 50°C and 7.0,respectively.Its activity was stimulated to different degrees in the presence of metal ions such as Ca2+,Mg2+,and some non-ionic surfactants.In addition,the purified lipase was activated by a series of water-miscible organic solvents such as some short carbon chain alcohols and was highly tolerant to some water-immiscible organic solvents.
文摘Terrain referenced navigation estimates an aircraft navigation status by utilizing a radar altimeter measuring a distance between the aircraft and terrain elevation. Accurate digital elevation map is essential to estimate the aircraft states correctly. However, the elevation map cannot represent the real terrain perfectly and there exists map error between the estimated and the true maps. In this paper, an influence of the map error on measurement equation is analyzed and a technique to incorporate the error in the filter is proposed. The map error is divided into two sources, accuracy error and resolution error. The effectiveness of the suggested technique is verified by simulation results. The method modifies a sensor noise covariance only so there is no additional computational burden from the conventional filter.
基金supported by the National Natural Science Foundation of China(Nos.31572193,31760615,and 31760584)111 Project(No.B14027)the Changjiang Scholars Program of China
文摘Aluminum(Al)is the most abundant metal element in the earth’s crust.On acid soils,at pH 5.5 or lower,part of insoluble Al-containing minerals become solubilized into soil solution,with resultant highly toxic effects on plant growth and development.Nevertheless,some plants have developed Al-tolerance mechanisms that enable them to counteract this Al toxicity.One such well-documented mechanism is the Al-induced secretion of organic acid anions,including citrate,malate,and oxalate,from plant roots.Once secreted,these anions chelate external Al ions,thus protecting the secreting plant from Al toxicity.Genes encoding the citrate and malate transporters responsible for secretion have been identified and characterized,and accumulating evidence indicates that regulation of the expression of these transporter genes is critical for plant Al tolerance.In this review,we outline the recent history of research into plant Al-tolerance mechanisms,with special emphasis on the physiology of Al-induced secretion of organic acid anions from plant roots.In particular,we summarize the identification of genes encoding organic acid transporters and review current understanding of genes regulating organic acid secretion.We also discuss the possible signaling pathways regulating the expression of organic acid transporter genes.
基金Project supported by the National Key Technology R&D Program of China(No.2007BAD59B06)the International Science and Technology Cooperation Program of China(No.2007DFA31260)
文摘We constructed an expression cassette of the organophosphorus pesticide degrading （opal） gene under the control of the E8 promoter. Then opd was transformed into tomato fruit using an agroinfiltration transient expression system. β-Glucuronidase （GUS） staining, reverse transcription-polymerase chain reaction （RT-PCR）, wavelength scanning, and fluorescent reaction were performed to examine the expression of the opd gene and the hydrolysis activity on coumaphos of organo- phosphorus hydrolase （OPH） in tomato fruit. The results show that the agroinfiltrated tomato fruit-expressed OPH had the maximum hydrolysis activity of about 11.59 Uhng total soluble protein. These results will allow us to focus on breeding transgenic plants that could not only enhance the degrading capability of fruit and but also hold no negative effects on pest control when spraying organophosphorus pesticides onto the seedlings in fields.
