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161.
Chiral high-performance liquid chromatography (HPLC) is one of the most powerful tools to prepare enantiopure standards of chiral compounds. In this study, the enantiomeric separation of imidazolinone herbicides, i.e., imazethapyr, imazapyr, and imazaquin, was investigated using chiral HPLC. The enantioselectivity of Chiralpak AS, Chiralpak AD, Chiralcel OD, and Chiralcel OJ columns for the three analytes was compared under similar chromatographic conditions. Chiralcel OJ column showed the best chiral resolving capacity among the test columns. The resolved enantiomers were distinguished by their signs of circular dichroism detected at 275 nm and their structures confirmed with LC-mass spectrometric analysis. Factors affecting the chiral separation of imidazolinones on Chiralcel OJ column were characterized. Ethanol acted as a better polar modifier than the other alcohols including 2-propanol, 1-butanol, and 1-pentanol. Although the acidic modifier in the mobile phase did not influence chiral recognition, it was necessary for reducing the retention time of enantiomers and suppressing their peak tailing. Thermodynamic evaluation suggests that enantiomeric separation of imidazolinones on Chiralcel OJ column is an enthalpy-driven process from 10 to 40 degrees C. This study also shows that small amounts of pure enantiomers of imidazolinones may be obtained by using the analytical chiral HPLC approach. 相似文献
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Navid Bazghaleh Chantal Hamel Yantai Gan Bunyamin Tar'an Joan Diane Knight 《Applied and environmental microbiology》2015,81(7):2368-2377
Increasing evidence supports the existence of variations in the association of plant roots with symbiotic fungi that can improve plant growth and inhibit pathogens. However, it is unclear whether intraspecific variations in the symbiosis exist among plant cultivars and if they can be used to improve crop productivity. In this study, we determined genotype-specific variations in the association of chickpea roots with soil fungal communities and evaluated the effect of root mycota on crop productivity. A 2-year field experiment was conducted in southwestern Saskatchewan, the central zone of the chickpea growing region of the Canadian prairie. The effects of 13 cultivars of chickpea, comprising a wide range of phenotypes and genotypes, were tested on the structure of root-associated fungal communities based on internal transcribed spacer (ITS) and 18S rRNA gene markers using 454 amplicon pyrosequencing. Chickpea cultivar significantly influenced the structure of the root fungal community. The magnitude of the effect varied with the genotypes evaluated, and effects were consistent across years. For example, the roots of CDC Corrine, CDC Cory, and CDC Anna hosted the highest fungal diversity and CDC Alma and CDC Xena the lowest. Fusarium sp. was dominant in chickpea roots but was less abundant in CDC Corrine than the other cultivars. A bioassay showed that certain of these fungal taxa, including Fusarium species, can reduce the productivity of chickpea, whereas Trichoderma harzianum can increase chickpea productivity. The large variation in the profile of chickpea root mycota, which included growth-promoting and -inhibiting species, supports the possibility of improving the productivity of chickpea by improving its root mycota in chickpea genetic improvement programs using traditional breeding techniques. 相似文献
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166.
A novel reductive graphene oxide‐based magnetic molecularly imprinted poly(ethylene‐co‐vinyl alcohol) polymers for the enrichment and determination of polychlorinated biphenyls in fish samples
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Saichai Lin Ning Gan Jiabin Zhang Xidong Chen Yuting Cao Tianhua Li 《Journal of molecular recognition : JMR》2015,28(6):359-368
The novel reductive graphene oxide‐based magnetic molecularly imprinted poly(ethylene‐co‐vinyl alcohol) polymers (rGO@m‐MIPs) were successfully synthesized as adsorbents for six kinds of polychlorinated biphenyls (PCBs) in fish samples. rGO@m‐MIPs was prepared by surface molecular imprinting technique. Besides, Fe3O4 nanoparticles (NPs) were employed as magnetic supporters, and rGO@Fe3O4 was in situ synthesis. Different from functional monomer and cross‐linker in traditional molecularly imprinted polymer, here, 3,4‐dichlorobenzidine was employed as dummy molecular and poly(ethylene‐co‐vinyl alcohol) was adopted as the imprinted polymers. After morphology and inner structure of the magnetic adsorbent were characterized, the adsorbent was employed for disperse solid phase extraction toward PCBs and exhibited great selectivity and high adsorption efficiency. This material was verified by determination of PCBs in fish samples combined with gas chromatography‐mass spectrometry (GC‐MS) method. According to the detection, the low detection limits (LODs) of PCBs were 0.0035–0.0070 µg l−1 and spiked recoveries ranged between 79.90 and 94.23%. The prepared adsorbent can be renewable for at least 16 times and expected to be a new material for the enrichment and determination of PCBs from contaminated fish samples. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
167.
Proteomic analysis of tilapia Oreochromis niloticus Streptococcus agalactiae strains with different genotypes and serotypes
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L. Li Y. Shi R. Wang T. Huang W. Liang H. Luo X. Gan W. Huang J. Li A. Lei M. Chen 《Journal of fish biology》2015,86(2):615-636
Nine tilapia Oreochromis niloticus group B streptococcus (GBS) strains differing in serotype and genotype were selected and paired. Two‐dimensional difference gel electrophoresis (2D DIGE) and matrix‐assisted laser‐desorption ionization time‐of‐flight‐mass spectrometry (MALDI‐TOF‐MS) were used to analyse the protein profiles of the strain pairs. Forty‐three proteins corresponding to 66 spots were identified, of which 35 proteins were found in the seven selected strain pairs that represented pairs differing in genotype and serotype. Among the 35 proteins, numbers of differentially expressed proteins in strains of different serotypes were greater than found in strains of different genotypes, suggesting that serotype plays a more essential role than genotype in the differential protein expression among GBS strains. No distinct pattern was found with respect to genotype and the protein expression profile of GBS strains. Several proteins were identified as surface‐associated cytoplasmic proteins that possessed the typical immunity‐eliciting characteristics of surface proteins. The identified proteins were found to be involved in 16 biological processes and seven Kyoto encyclopaedia of genes and genomes (KEGG) pathways. The data, for the first time, identified differentially expressed proteins in O. niloticus GBS strains of different serotypes, which play a major role in immunogenicity of O. niloticus GBS than does genotype, offering further information for design of a vaccine against O. niloticus GBS. 相似文献
168.
Crustal fluid and ash alteration impacts on the biosphere of Shikoku Basin sediments,Nankai Trough,Japan
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M. E. Torres T. Cox W.‐L. Hong J. McManus J. C. Sample C. Destrigneville H. M. Gan H. Y. Gan J. W. Moreau 《Geobiology》2015,13(6):562-580
We present data from sediment cores collected from IODP Site C0012 in the Shikoku Basin. Our site lies at the Nankai Trough, just prior to subduction of the 19 Ma Philippine Sea plate. Our data indicate that the sedimentary package is undergoing multiple routes of electron transport and that these differing pathways for oxidant supply generate a complex array of metabolic routes and microbial communities involved in carbon cycling. Numerical simulations matched to pore water data document that Ca2+ and Cl1‐ are largely supplied via diffusion from a high‐salinity (44.5 psu) basement fluid, which supports the presence of halophile Archean communities within the deep sedimentary package that are not observed in shallow sediments. Sulfate supply from basement supports anaerobic oxidation of methane (AOM) at a rate of ~0.2 pmol cm?3 day?1 at ~400 mbsf. We also note the disappearance of δ‐Proteobacteria at 434 mbsf, coincident with the maximum in methane concentration, and their reappearance at 463 mbsf, coinciding with the observed deeper increase in sulfate concentration toward the basement. We did not, however, find ANME representatives in any of the samples analyzed (from 340 to 463 mbsf). The lack of ANME may be due to an overshadowing effect from the more dominant archaeal phylotypes or may indicate involvement of unknown groups of archaea in AOM (i.e., unclassified Euryarchaeota). In addition to the supply of sulfate from a basement aquifer, the deep biosphere at this site is also influenced by an elevated supply of reactive iron (up to 143 μmol g?1) and manganese (up to 20 μmol g?1). The effect of these metal oxides on the sulfur cycle is inferred from an accompanying sulfur isotope fractionation much smaller than expected from traditional sulfate‐reducing pathways. The detection of the manganese‐ and iron‐reducer γ‐Proteobacteria Alteromonas at 367 mbsf is consistent with these geochemical inferences. 相似文献
169.
Yan Gan Qiang Chen Shijun Zhang Shenghong Ju Zhi-Yong Li 《Biomedical engineering online》2015,14(Z1):S9
Background
Different from other indicators of cardiac function, such as ejection fraction and transmitral early diastolic velocity, myocardial strain is promising to capture subtle alterations that result from early diseases of the myocardium. In order to extract the left ventricle (LV) myocardial strain and strain rate from cardiac cine-MRI, a modified hierarchical transformation model was proposed.Methods
A hierarchical transformation model including the global and local LV deformations was employed to analyze the strain and strain rate of the left ventricle by cine-MRI image registration. The endocardial and epicardial contour information was introduced to enhance the registration accuracy by combining the original hierarchical algorithm with an Iterative Closest Points using Invariant Features algorithm. The hierarchical model was validated by a normal volunteer first and then applied to two clinical cases (i.e., the normal volunteer and a diabetic patient) to evaluate their respective function.Results
Based on the two clinical cases, by comparing the displacement fields of two selected landmarks in the normal volunteer, the proposed method showed a better performance than the original or unmodified model. Meanwhile, the comparison of the radial strain between the volunteer and patient demonstrated their apparent functional difference.Conclusions
The present method could be used to estimate the LV myocardial strain and strain rate during a cardiac cycle and thus to quantify the analysis of the LV motion function.170.
Yu Zhang Rong-quan He Yi-wu Dang Xiu-ling Zhang Xiao Wang Su-ning Huang Wen-ting Huang Meng-tong Jiang Xiao-ning Gan You Xie Ping Li Dian-zhong Luo Gang Chen Ting-qing Gan 《Cancer cell international》2015,16(1):89