Elemental and redox analysis of single bacterial cells by x-ray microbeam analysis

High-energy x-ray fluorescence measurements were used to make elemental maps and qualitative chemical analyses of individual Pseudomonas fluorescens strain NCIMB 11764 cells. Marked differences between planktonic and adhered cells were seen in the morphology, elemental composition, and sensitivity to Cr(VI) of hydrated cells at spatial scales of 150 nm. This technology can be applied to natural geomicrobiological systems.     

不同盐度条件下秋茄根系单宁含量动态变化

对不同盐度(0‰-40‰)栽培下秋茄根的总酚、可溶性缩合单宁、结合缩合单宁、总缩合单宁的含量进行测定,探讨盐度对单宁生产的效应.结果表明:(1)不同盐度下栽培60-135d,总酚含量在相同盐度条件下随栽培时间的延长呈现出先波动而后升高的趋势,其中总酚最高含量出现在高盐度,说明一定的高盐度胁迫可以促进总酚的合成;总缩合单宁与可溶性缩合单宁含量变化趋势相似,其中可溶性缩合单宁含量显著高于结合缩合单宁.(2)在15‰盐度下栽培75-135d,秋茄根不同部位的总酚、可溶性缩合单宁、结合缩合单宁和总缩合单宁含量有相似的变化趋势,即由根尖往远离根尖的部位呈下降趋势.     

四川省优质安全农产品物流配送体系发展战略研究

分析了农产品物流配送的特点和模式，并针对四川省农产品物流配送的现状和问题．提出四川省优质安全农产品物流配送体系的发展思路及其发展对策。     

Axonal neuregulin-1 regulates myelin sheath thickness

In the nervous system of vertebrates, myelination is essential for rapid and accurate impulse conduction. Myelin thickness depends on axon fiber size. We use mutant and transgenic mouse lines to show that axonal Neuregulin-1 (Nrg1) signals information about axon size to Schwann cells. Reduced Nrg1 expression causes hypomyelination and reduced nerve conduction velocity. Neuronal overexpression of Nrg1 induces hypermyelination and demonstrates that Nrg1 type III is the responsible isoform. We suggest a model by which myelin-forming Schwann cells integrate axonal Nrg1 signals as a biochemical measure of axon size.     

5种榕属植物不同发育阶段叶片的热值与灰分含量动态

对厦门园林植物园的5种榕属植物不同发育阶段叶片的灰分含量、干质量热值与去灰分热值的变化动态进行了初步研究。结果表明:①随着叶片的发育(从幼叶→成熟叶→老叶),灰分含量有升高的趋势,5种植物中老叶灰分含量均不是最低,说明叶片可能具有维持自身营养元素平衡的机制;②5种榕属植物不同发育阶段的叶片中,幼叶含有较高的干质量热值,不同发育阶段的榕属植物叶片干质量热值变化趋势因种而异;③5种榕属植物不同发育阶段叶片的干质量热值与灰分含量具有显著的线性相关(P<0 05);④不同发育阶段叶片去灰分热值的变化趋势因种而异,也不是固定不变的。表4参16     

Comparative genome and proteome analysis of Anopheles gambiae and Drosophila melanogaster

Comparison of the genomes and proteomes of the two diptera Anopheles gambiae and Drosophila melanogaster, which diverged about 250 million years ago, reveals considerable similarities. However, numerous differences are also observed; some of these must reflect the selection and subsequent adaptation associated with different ecologies and life strategies. Almost half of the genes in both genomes are interpreted as orthologs and show an average sequence identity of about 56%, which is slightly lower than that observed between the orthologs of the pufferfish and human (diverged about 450 million years ago). This indicates that these two insects diverged considerably faster than vertebrates. Aligned sequences reveal that orthologous genes have retained only half of their intron/exon structure, indicating that intron gains or losses have occurred at a rate of about one per gene per 125 million years. Chromosomal arms exhibit significant remnants of homology between the two species, although only 34% of the genes colocalize in small "microsyntenic" clusters, and major interarm transfers as well as intra-arm shuffling of gene order are detected.     

Biflavonoids from Caper (Capparis spinosa L.) fruits and their effects in inhibiting NF-kappa B activation

Caper (Capparis spinosa L.) fruits have been widely used as food and folk medicine in the Mediterranean basin and in central and west Asia. In this study, two biflavonoids, isoginkgetin, and ginkgetin, together with three other flavonoids, were isolated from caper fruits. Their chemical structures were elucidated by spectroscopic analyses and comparison with literature. To our knowledge, isoginkgetin, ginkgetin and sakuranetin were identified in caper for the first time. Notably, it is also the first time that biflavonoids have ever been found in the Capparidaceae. Concentrations of the two biflavonoids were measured in caper fruits collected from four major growing areas in northwest China. The anti-inflammatory effects of the flavonoids from caper fruits were evaluated by secreted placental alkaline phosphatase (SEAP) reporter assay, which was designed to measure nuclear factor-kappa B (NF-κB) activation. Isoginkgetin and ginkgetin showed inhibitory effects in initial screen at 20 μM, while the effect of ginkgetin was much greater than that of isoginkgetin. In a dose-response experiment, the IC(50) value of ginkgetin was estimated at 7.5 μM, suggesting it could be a strong NF-κB inhibitor and worthy of study in vivo.     

Synthesis,fungicidal activity,and 3D-QSAR of pyridazinone-substituted 1,3,4-oxadiazoles and 1,3,4-thiadiazoles

A series of novel 5-[1-aryl-1,4-dihydro-6-methylpyridazin-4-one-3-yl] -2-arylamino-1,3,4-oxadiazoles, fungicidally active, were synthesized based on bioisosterism and tested in vivo against wheat leaf rust, Puccinia recondita. These compounds were shown to be fungicidally active, and their activity was influenced by the nature of the substituents. By using the three-dimensional quantitative structure-activity relationships (3D-QSAR) method of comparative molecular field analysis (CoMFA), we have studied the structure and activity relationship of the compounds containing both pyridazinone-substituted 1,3,4-thiadiazoles and pyridazinone-substituted 1,3,4-oxadiazoles. The 3D-QSAR modes gave good correlation between the variations on percent inhibition and the steric-electrostatic properties. The results are consistent with a common mode of action for the pyridazinone-substituted 1,3,4-thiadiazoles and the pyridazinone-substituted 1,3,4-oxadiazoles, which further confirms that the 1,3,4-oxadiazole ring is a bioisosteric analogue of the 1,3,4-thiadiazole ring. These offer important structural insights into designing highly active compounds prior to their synthesis.