Authors:Y. Cheng, H. F. Wang, H. F. Sun, H. L. Li, Y. F. Liu, S. X. Peng, K. X. Liu, and Z. Y. Guo
Accelerator mass spectrometry (AMS) is an ultra-sensitive method to monitor and trace the environmental exposure levels of 14C-labeled molecules in vivo. Nicotine [3-(1-methyl-2-pyrrolidinyl)-pyridine], a major alkaloid in tobacco products, has proven to be a potential genotoxic compound. Using 14C-labeled nicotine and AMS, we have investigated the inhibitory effect of curcumin, garlic squeeze, grapeseed extract, tea polyphenols, vitamin C and vitamin E, respectively, on nicotine-hemoglobin (Hb) adduction in vivo. The results demonstrated that these dietary constituents induced remarkable decrease of nicotine-Hb adducts. The inhibitory fact may afford an important clue of the chemoprevention of the potential nicotine-induced carcinogenesis.
Authors:H. Dong, Y. Wang, Y. Ou, J. She, X. Shen, J. Li, C. Zhang, and L. Liu
Molecularly imprinted polymers (MIPs) were synthesized by imprinting a new template—S(-)-1,1′-binaphthalene-2,2′-diamine (S-DABN) and applied as chiral stationary phases for chiral separation of DABN racemates by high-performance liquid chromatography (HPLC). The influence of some key factors on the chiral recognition ability of MIPs, such as the type of functional monomers and porogen and the molar ratio of template to monomer, was systematically investigated. The chromatographic conditions, such as mobile phase composition, sample loading, and flow rate, were also measured. The chiral separation for DABN racemates under the optimum chromatographic conditions by using MIP chiral stationary phase (CSP) of P3, prepared with the S-DABN/MAA ratio = 1/4 and used acetonitrile (2 mL) and chloroform (4 mL) as porogen, showed the highest separation factor (2.14). Frontal analysis was used to evaluate affinity to the target molecule of MIPs. The binding sites (Bt) of MIPs and dissociation constant (Kd) were estimated as 4.56 μmol g−1 and 1.40 mmol L−1, respectively. In comparison with the previous studies, this approach had the advantages, such as the higher separation factor, easy preparation, and cost-effectiveness, it not only has the value for research but also has a potential in industrial application.
Authors:W.-Y. Liu, Sh.-L. Xie, X.-Zh. Xu, Ch.-Y. Wu, and F. Feng
Oroxylin A (5,7-dihydroxy-6-methoxyflavone), which has showed multiple pharmacological effects, was semi-synthesized chemically as a pharmaceutical agent. Its impurities, degradation products and their formation pathways remain unknown. In the present study, two impurities (5,6,7-trihydroxyflavone, 5-hydroxy-6,7-dimethoxytlavone) and a degradation product (5,7-dihydroxy-8-methoxyflavone) in Oroxylin A bulk drug substance were identified, and their formation pathways were proposed. A reversed phase liquid chromatographic method for the simultaneous determination of Oroxylin A and the three compounds was developed on a C18 column using methanol-acetonitrile-0.1% acetic acid (54:23:23, v/v/v) as the mobile phase. The detection was performed at 271 nm. The method was validated to be robust, precise, specific and linear between 4 and 40 μg mL−1; the limits of detection and quantification of Oroxylin A were 0.01 and 0.04 μg mL−1, respectively. The developed method was found to be suitable to check the quality of bulk samples of Oroxylin A at the time of batch release and also during its stability studies (long term and accelerated stability).
Authors:J. Fan, S. Zhang, J. Lu, J. Liu, X. Zhang, Y. Ding, and Y. Chang
In order to measure 182Hf by accelerator mass spectrometry (AMS), a chemical procedure for separation of hafnium from tungsten has been developed
by extraction chromatography. The extraction chromatographic behavior of hafnium and tungsten has been studied using tri-n-octylamine (TOA) as the stationary phase, HCl–H2O2 mixture and NH3·H2O as the mobile phase. The effects of H2O2 concentration, column loading and column dimensions are investigated. Hf and W with microgram amounts are successfully separated
on a chromatographic column (Ø5 × 196 mm), on which Hf is hardly retained after completely eluted with 6 M HCl–1% H2O2 and W strongly adsorbed is then eluted with 3 M NH3·H2O. The decontamination factor for tungsten is 3.0 × 105 and the recovery of hafnium is better than 99% using a single column separation.
Authors:J. Shao, Y. Yang, B. Li, L. Zhang, Y. Chen, and X. Liu
Two compounds of antimony trichloride and bismuth trichloride with valine are synthesized by solid phase synthesis at room
temperature. Their compositions, determined by element analysis, are Sb(C5H10O2N)3·2H2O and Bi(C5H10O2N)2Cl·0.5H2O. The crystal structure of antimony complex with valine belongs to triclinic system and its lattice parameters are: a=0.9599 nm, b=1.5068 nm, c=1.9851 nm, α=92.270, β=95.050, γ=104.270. The crystal structure of bismuth complex with valine belongs to monoclinic system
and its lattice parameters are: a=1.6012 nm, b=1.8941 nm, c=1.839 nm, β=99.73°. The far-infrared spectra and infrared spectra show that the amino group and carboxyl of valine may be
coordinated to antimony and bismuth, respectively, in two compounds. The TG-DSC results also reveal that the complexes were
This study aims to develop and validate a high-performance size-exclusion chromatography (HPSEC) method to determine the amount of polymer in cefmetazole sodium for injection and to compare this method with gel chromatography. A Zenix SEC-150 column was used with the mobile phase of phosphate buffer solution (pH 7.0; 0.01 M)—acetonitrile (90:10 v/v) at a flow rate of 0.8 mL min−1 and a detection wavelength of 240 nm. The polymer was quantified by an external standard method with self-control, and the amount was expressed by the percentage of cefmetazole. The HPSEC method was validated for specificity, linearity, and precision. The chromatographic conditions, chromatographic performances, sensitivity, linearity, and precision of the developed HPSEC method and gel chromatography were compared, and both methods were subsequently used to determine the amount of polymer from seven batches of samples. The HPSEC method was fully validated. The time of isocratic elution for sample assay was less than 14 min. The results of comparison indicate that the developed HPSEC method was superior to gel chromatography. The Student t test results also showed significant difference in the amount of polymer from the samples obtained by the two methods. Thus, the HPSEC method with two obvious advantages, the superior sensitivity and a shorter analysis time, is more suitable for determination of polymer amount in cefmetazole sodium for injection to control the quality of the product.
Soil moisture is a major driving force of plant community succession in restored meadows. Existing studies mainly focus on diversity-productivity relationships. However, studies which determine the effects of soil moisture on the plant community properties in restored meadows are lacking. In this study, we conducted a chronosequence analysis of the interactions between soil water content variation and plant community properties in meadows following passive restoration (3-, 5-, 9-, 14-, 17-, 21-year restoration) of abandoned farmlands on the Sanjiang Plain, China. Results showed that the plant community was characterized by ruderal plants in the initial year of succession, and then by perennial plants such as Calamagrostis angustifolia and Carex spp. in older restored meadows. Similarity of restored community to target site increased across succession time whereas species diversity gradually decreased. Plant height, coverage and biomass increased with restoration time, with plant density being the exception. The community height, coverage and root/shoot ratio were positively related to the water content in the surface soil layer (0–10 cm). Conversely, plant density was significantly and negatively related with soil moisture at 0–10 cm soil depth. Plant diversity (Shannon index, Richness index and evenness) was closely correlated to soil water content at the soil depth of 0–10 cm. Our findings indicate that vegetation of cultivated meadows could be effectively restored by passive restoration. Change of plant species diversity is an especially important response to hydrological recovery in restored meadows on the Sanjiang Plain.
Authors:X. Zhang, Y. Chen, Y. Wei, W. Lu, H. Liao, Y. Liu, X. Yang, X. Li, L. Yang, L. Li, and R. Li
Partial abortion of gametes possessing
genotype at locus
is responsible for hybrid sterility between indica and japonica subspecies in rice (
L.), while a single wide compatibility (WC) allele
can restore normal hybrid fertility between the two groups. In this study, Pei’ai 64S, one of the most popular WC line widely used for subspecific hybrid rice breeding program in South China was studied for location of its
locus. Twenty SSR (Simple Sequence Repeat) markers derived from Cornell SSR linkage map and 9 developed using sequences from GenBank database were employed to perform bulked segregant analysis of the mapping population derived from a three-way cross (Pei’ai 64S/T8//Akihikari) to tag fine location of the hybrid sterility locus,
locus was mapped on chromosome 6 approximately 0.2 cM from GXR6 and RM276 SSR markers. This tight linkage of the markers and the S-5 locus would be very useful for efficient marker-assisted selection for WC varieties and for map-based cloning of the gene.
Aegilops sharonensis (Sharon goatgrass) is a valuable source of novel high molecular weight glutenin subunits, resistance to wheat rust, powdery mildew, and insect pests. In this study, we successfully hybridized Ae. sharonensis as the pollen parent to common wheat and obtained backcross derivatives. F1 intergeneric hybrids were verified using morphological observation and cytological and molecular analyses. The phenotypes of the hybrid plants were intermediate between Ae. sharonensis and common wheat. Observations of mitosis in root tip cells and meiosis in pollen mother cells revealed that the F1 hybrids possessed 28 chromosomes. Chromosome pairing at metaphase I of the pollen mother cells in the F1 hybrid plants was low, and the meiotic configuration was 25.94 I + 1.03 II (rod). Two pairs of primers were screened out from 150 simple sequence repeat markers, and primer WMC634 was used to identified the presence of the genome of Ae. sharonensis. Sequencing results showed that the F1 hybrids contained the Ssh genome of Ae. sharonensis. The sodium dodecyl sulfate polyacrylamide gel electrophoresis profile showed that the alien high molecular weight glutenin subunits of Ae. sharonensis were transferred into the F1 and backcross derivatives. The new wheat-Ae. sharonensis derivatives that we have produced will be valuable for increasing resistance to various diseases of wheat and for improving the quality of bread wheat.
Authors:X.-J. Chen, W. Miao, Y. Liu, Y.-F. Shen, W.-S. Feng, T. Yu, and Y.-H. Yu
Using isothermal microcalorimetry, the growth power-time
curves of three strains of Tetrahymena
were determined at 28C. Their Euclidean distances and cluster analysis
diagram were obtained by using two thermokinetic parameters (r
and Qlog), which
showed that T. thermophila BF1
and T. thermophila BF5
had a closer relationship. Compared with the single molecular biomarker (ITS1)
method, microcalorimetry wasmaybe a simpler, more sensitive andmore economic
technique in the phylogenetic studies of Tetrahymena