摘要：
The cell culture in a production medium in the dark is capable of producing a large quantity of shikonin and its derivatives, which were completely inhibited when the cell cultures were irradiated with continuous white light and blue light and partially repressed under continuous red light. The expressions of PAL1, 4CL1, and CYP98A6 were induced under continuous red, blue and white light. Transcript levels of HMGR and LDI2 gradually were decreased in the dark and under continuous red light, while no transcriptional product of LDI2 was detected under blue and white light. C4H2 and LePGT1 genes were constantly expressed irrespective of different light conditions. Among the genes studied, the expression of LDI2 was critical for light-regulated shikonin formation. The inducible expression of PAL1, 4CL1, and CYP98A6 as well as the inhibitory transcription of LDI2 mediated by continuous red light irradiation were likely accounted for the reduced accumulation of shikonin.
摘要：
Platinum nanowire (PtNW) can be grown by electrodeposition in polycarbonate membrane, with the average diameter of the nanowires about 250 nm. The PtNW and multiwalled carbon nanotubes (CNT) are then dispersed into chitosan (CHIT) solution. The resulting PtNW-CNT-CHIT material brings new capabilities for electrochemical devices by using the synergistic action of the electrocatalytic activity of PtNW and CNT. By dropping the PtNW-CNT-CHIT film onto the glassy carbon (GC) electrode surface, and after evaporation an amperometric sensor for the determination of indole-3-acetic acid (IAA) was developed. The oxidation current of IAA increased significantly at the PtNW-CNT-CHIT film coated GC electrode, in contrast to that at the CNT-CHIT modified GC. The linear response of the sensor is from 50 ng/ml to 50 μg/ml with a detection limit of 25 ng/mL.
通讯机构：
[Luo, ZY] C;Cent S Univ, Coll Biol Sci & Technol, Inst Mol Biol, Changsha 410078, Peoples R China.
关键词：
Aspergillus niger polysaccharide;elicitor;GBR6 mRNA expression;ginsenoside biosynthesis;ginsenoside biosynthesis candidate genes;mRNA differential expression;Panax ginseng C. A. Meyer
摘要：
To explore the mode of the spatio-temporal expression of six newly discovered ginsenoside biosynthesis candidate gene transcripts, both Northern blotting and semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) were used to elucidate the mRNA expression levels of the transcripts in various tissues and organs of Panax ginseng C. A. Meyer during different growth development stages. The six gene transcripts were all differentially expressed in cultured callus, root, stem, leaf, and seed.The mRNA expression levels were significantly higher in four-year-old roots than in one-year-old roots, and results of semi-quantitative RT-PCR assays were in accordance with those of Northern blotting analyses.The results strongly suggest that all six genes were differentially expressed at root-specific developmental stages. In particular, when a quiescent early stage culture suspension of P. ginseng cells was exposed to the ginsenoside biosynthesis-promoting elicitor Aspergillus niger polysaccharide, the GBR6 gene transcript response showed time-dependent increments and was parallel with ginsenoside productivity (P ＜ 0.01).Overexpression of the GBR6 gene is likely to play a critically important role in the biosynthesis of ginsenosides.The results of the present study provided a background for the further elucidation of the structure and physiological function of these six candidate genes.
摘要：
β-ocimene, a kind of monoterpene, was found recently as a plant communication signal molecule. It has two isomeric forms in nature: cis-β-ocimene and trans-β-ocimene. According to recent reports, all investigated plants, such as corn, cotton, lima bean, potato, tobacco, arabidopsis, and Mediterranean pine, could release the chemical component β-ocimene after fed by arthropod herbivores,
期刊：
Theoretical and Applied Genetics,2004年108(7):1434-1442 ISSN：0040-5752
通讯作者：
Jannink, JL
作者机构：
[Jannink, JL] Iowa State Univ Sci & Technol, Dept Agron, Ames, IA 50011 USA.;Hunan Agr Univ, Ctr Life Sci Res, Hunan 410128, Peoples R China.
通讯机构：
[Jannink, JL] I;Iowa State Univ Sci & Technol, Dept Agron, Ames, IA 50011 USA.
摘要：
In a population intended for breeding and selection, questions of interest relative to a specific segregating QTL are the variance it generates in the population, and the number and effects of its alleles. One approach to address these questions is to extract several inbreds from the population and use them to generate multiple mapping families. Given random sampling of parents, sampling strategy may be an important factor determining the power of the analysis and its accuracy in estimating QTL variance and allelic number. We describe appropriate multiple-family QTL mapping methodology and apply it to simulated data sets to determine optimal sampling strategies in terms of family number versus family size. Genomes were simulated with seven chromosomes, on which 107 markers and six QTL were distributed. The total heritability was 0.60. Two to ten alleles were segregating at each QTL. Sampling strategies ranged from sampling two inbreds and generating a single family of 600 progeny to sampling 40 inbreds and generating 40 families of 15 progeny each. Strategies involving only one to five families were subject to variation due to the sampling of inbred parents. For QTL where more than two alleles were segregating, these strategies did not sample QTL alleles representative of the original population. Conversely, strategies involving 30 or more parents were subject to variation due to sampling of QTL genotypes within the small families obtained. Given these constraints, greatest QTL detection power was obtained for strategies involving five to ten mapping families. The most accurate estimation of the variance generated by the QTL, however, was obtained with strategies involving 20 or more families. Finally, strategies with an intermediate number of families best estimated the number of QTL alleles. We conclude that no overall optimal sampling strategy exists but that the strategy adopted must depend on the objective.
摘要：
Trigonelline (TRG), which act as a cell cycle regulator and a compatible solute in response to salinity and water-stress, is the N-methyl conjugate of nicotinic acid the formation of which is catalyzed by S-adenosyl-L-methionine nicotinic acid-N-methyltransferase. The enzyme was purified 2650-fold from soybean (Glycine max L.) leaves with a recovery of 4 %. The purification procedure included ammonium sulfate (45 - 60 %) precipitation, linear gradient DEAE-Sepharose chromatography, adenosine-agarose affinity chromatography, hydroxyapatite chromatography and gel filtration (Sephacryl-S-200). The purified enzyme preparation showed a major band with a molecular mass of 41.5 kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis that is related to the enzyme activity. The native enzyme had a molecular mass of about 85 kDa as estimated by gel filtration. The K m values for S-adenosyl-L- methionine and nicotinic acid were 31 and 12.5 μM, respectively. The purified enzyme showed optimum activity at pH 6.5 and temperature of 40 - 45°C. High concentration of dithiothreitol (10 mM) and glycerol (20 %) stabilize the enzyme during purification and storage. Hg 2+ strongly inhibits enzyme activity.
作者机构：
[Jannink, JL] Iowa State Univ, Dept Agron, Ames, IA 50011 USA.;Hunan Agr Univ, Ctr Life Sci Res, Changsha 410218, Hunan, Peoples R China.
通讯机构：
[Jannink, JL] I;Iowa State Univ, Dept Agron, Ames, IA 50011 USA.
摘要：
When multiple related families derived from inbred lines are jointly analysed to detect quantitative trait loci (QTLs), the analysis should estimate allelic effects as accurately as possible and estimate the probability that different parents carry alleles that are identical in state. Analyses exist that assume that all parents carry unique alleles or that all parents but one carry the same allele. In practice, many configurations are possible that group different parents according to their identity-in-state condition at a putative QTL allele. Here, we propose a variable model Bayesian analysis that selects among possible identity-in-state configurations and jointly estimates the allelic effects of identical-in-state parents. We contrast this analysis with a fixed model analysis that estimates unique allelic effects for all parents. We analyse two simulated mating designs: an experimental design in which three inbred parents were crossed to generate two families of 150 doubled haploid lines; and a breeding design in which 20 inbred parents were crossed to generate 60 families of 20 doubled haploid lines, with each parent contributing to six families. In all cases where some parents were simulated to carry alleles of identical effect (that is, they were identical in state), the variable analysis estimated allelic effects with lower mean-squared error than the fixed analysis. The variable analysis showed that, unless each family contains many individuals (more than 100), there is insufficient information in DNA-marker and phenotypic data to determine with high probability the QTL allelic number.
摘要：
A novel piezoelectric immunosensor has been developed for the determination of β-indole acetic acid (IAA) in dilute solutions. The detection is based on competitive immunoreaction between a hapten (IAA) and an antigen (IAA-BSA, hapten-protein conjugation) bound to an anti-IAA antibody, immobilized on a quartz crystal microbalance (QCM). The frequency change (y) of the sensor caused by antigen is linearly related to the logarithm of the concentration of IAA (x) in the range of 0.5 ng/ml - 5 μg/ml with a regression equation of the form y = - 23x + 151 (r = 0.9937).
