陕西杨凌地区黑光灯下金龟甲种类组成及优势种群发生动态

2011年5～9月,在陕西省杨凌区西北农林科技大学植物保护学院试验站设置黑光灯,系统诱集金龟甲并鉴定种类,分析金龟甲种群的发生动态。结果表明,陕西杨凌地区黑光灯可诱到金龟甲3科17种,从5月上旬至9月上旬均可发生,以6月下旬至7月中旬为发生盛期;优势种类为铜绿丽金龟、赤绒鳃金龟、华北大黑鳃金龟和暗黑鳃金龟,发生盛期分别为6月下旬至7月下旬、7月下旬至8月上旬、7月上旬和6月下旬至7月下旬。     

西双版纳人工林林窗光照剖线分布特征

以林窗北缘为中心,研究了西双版纳地区橡胶林林窗及周边Ｎ－Ｓ样带上光照水平梯度分布。结果表明：林窗的发生导致光照明显增加,从林内到林窗中央,光强呈明显增大趋势,上午雾末消退时,相对光照强度水平梯度变化曲线峰值出现于林窗中央,午后雾消退后,林窗边缘为相对光强梯度变化最甚的地段,峰值由林窗中央向林窗北缘移进。林窗边缘,林窗中央及林内光照强度日变化曲线均为不对称的单峰型,但峰值出现和振幅不同。在太阳高度角     

Interaction of the Neurospora crassa heat shock factor with the heat shock element during heat shock and different developmental stages

The interaction of the heat shock factor (HSF) with the heat shock element (HSE) was determined by a non-radioactive electrophoretic mobility shift assay, in order to analyze HSF regulation in Neurospora crassa. HSF binds to HSE under normal, non-stress conditions and is thus constitutively trimerized. Upon heat shock, the HSF-HSE complex shows a retarded mobility. This was also observed in Saccharomyces cerevisiae, where this mobility shift was shown to be due to HSF phosphorylation [Sorger and Pelham (1988) Cell 54, 855-864]. In N. crassa, HSE-dependent electrophoretic mobility shift is temperature- and time-dependent. Under normal growth conditions, the HSF is located in the cytoplasm as well as in the nucleus. In germinating conidia the HSF shows a retarded mobility typical for heat shock even at normal growth temperatures. No HSF-dependent mobility shift was detectable in aerial hyphae.     

Laser-induced Breakdown Spectroscopy: A New Approach for Nanoparticle's Mapping and Quantification in Organ Tissue

Emission spectroscopy of laser-induced plasma was applied to elemental analysis of biological samples. Laser-induced breakdown spectroscopy (LIBS) performed on thin sections of rodent tissues: kidneys and tumor, allows the detection of inorganic elements such as (i) Na, Ca, Cu, Mg, P, and Fe, naturally present in the body and (ii) Si and Gd, detected after the injection of gadolinium-based nanoparticles. The animals were euthanized 1 to 24 hr after intravenous injection of particles. A two-dimensional scan of the sample, performed using a motorized micrometric 3D-stage, allowed the infrared laser beam exploring the surface with a lateral resolution less than 100 μm. Quantitative chemical images of Gd element inside the organ were obtained with sub-mM sensitivity. LIBS offers a simple and robust method to study the distribution of inorganic materials without any specific labeling. Moreover, the compatibility of the setup with standard optical microscopy emphasizes its potential to provide multiple images of the same biological tissue with different types of response: elemental, molecular, or cellular.     

Anti-proliferative effect of chalcone derivatives through inactivation of NF-κB in human cancer cells

To investigate the anti-proliferative effect of NF-κB inhibitor, a series of analogs of (E)-1-(2-hydroxy-6-(isopentyloxy)phenyl)-3-(4-hydroxyphenyl)prop-2-en-1-one (5a) were prepared and evaluated for their NF-κB inhibition and anti-proliferative activity against various human cancer cell lines. Compounds (E)-1-(2-(3,3-dimethylbutoxy)-6-hydroxyphenyl)-3-(4-hydroxyphenyl)prop-2-en-1-one (5e) and (E)-4-(3-(2-(3,3-dimethylbutoxy)-6-hydroxyphenyl)-3-oxoprop-1-enyl)benzenesulfonamide (5p) showed good NF-κB inhibition as well as potent anti-proliferative activity. SAR studies showed that all the compounds with potent or moderate NF-κB inhibition displayed good anti-proliferative activity. All the analogs (5b–r) maintained a good correlation between their NF-κB inhibition and anti-proliferative activity though the extent is not directly proportional to each other.     

Higher-Order Thalamocortical Inputs Gate Synaptic Long-Term Potentiation via Disinhibition

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半干旱黄土高原苜蓿草地撂荒过程土壤水分变化特征

土壤水分是黄土高原植被恢复和生态建设的主要限制因子,明确土壤水分随植被演替的变化规律是阐明黄土高原植被与水分相互作用机制的重要基础。以半干旱黄土高原小流域苜蓿草地撂荒过程为研究对象,通过对2016-2018年生长季苜蓿群落、苜蓿+赖草群落、赖草群落和长芒草群落四种草地群落0-1.8 m土壤水分进行动态监测以及0-5 m深度土壤水分测定,分析不同演替阶段苜蓿草地土壤水分的动态特征,探讨土壤水分对苜蓿草地撂荒过程的响应。结果表明：（1）在苜蓿草地撂荒演替过程中,土壤水分随群落恢复时间的延长呈先增加后降低的变化,降水的年际动态显著影响不同演替群落的土壤水分响应;（2）0-0.4 m土壤水分主要受降水影响,使得各草地群落在这一层次没有显著差异（P>0.05）,而1 m以下的土壤水分含量则主要受植被类型的影响,各草地群落之间存在显著差异（P<0.05）;（3）0-5 m深层土壤水分随群落的演替,1 m以下各土层土壤水分含量逐渐增加,表明撂荒过程中使土壤水分得到了一定程度的恢复。研究结果揭示了苜蓿草地撂荒过程土壤水分的变化规律,可为黄土高原生态恢复提供理论依据。     

Development of highly nutritive culture media

Summary A highly nutritive culture medium (MGM-464) was developed for insect cell primary culture. The new medium consists of 6 inorganic salts, 4 organic acids, 21 amino acids, 3 sugars, 10 vitamins, and 8 other chemicals, including natural substances. The complete medium was generated by adding 20 ml fetal bovine serum to 100 ml MGM-464. The detail of the composition of the medium is given in a table, and the protocol to prepare the medium is described in the text. Among the 15 kinds of cultures made with MGM-464, embryonic cells from a walking stick and ovarian cells from the common white were subcultured more than 70 times, and embryonic cells of a chrysomelid beetle were subcultured more than 15 times. Other cultures could not be subcultured. However, embryonic cells from the commercial silkworm and a cockroach, ovarial cells from the commercial silkworm and a sphingid moth, nervous cells from the commercial silkworm and two sphingid moths, and cells from the dorsal vessel plus surrounding tissue of the commercial silkworm survived for several mo. The cells from the honeybee embryos, aphid embryos, and planthopper embryos were rather short-lived, and deteriorated after about 1 mo.     

X-Ray Analysis of the Magnesium-containing Endonuclease from Serratia marcescens

The three-dimensional crystal structure of the DNA/RNA nonspecific endonuclease from Serratia marcescenswas refined at the resolution of 1.07 Å to Rfactor of 12.4% and R _freefactor of 15.3% using the anisotropic approximation. The structure includes 3924 non-hydrogen atoms, 715 protein-bound water molecules, and a Mg²⁺ion in each binding site of each subunit of the nuclease homodimeric globular molecule. The 3D topological model of the enzyme was revealed, the inner symmetry of the monomers in its N-and C-termini was found, and the local environment of the magnesium cofactor in the nuclease active site was defined. Mg²⁺ion was found to be bound to the Asn119 residue and surrounded by five associated water molecules that form an octahedral configuration. The coordination distances for the water molecules and the O¹atom of Asn119 were shown to be within the range of 2.01–2.11 Å. The thermal factors for the magnesium ion in subunits are 7.08 and 4.60 Ų, and the average thermal factors for the surrounding water molecules are 11.14 and 10.30 Ų, respectively. The region of the nuclease subunit interactions was localized, and the alternative side chain conformations were defined for 51 amino acid residues of the nuclease dimer.     

发酵食品中乳酸菌的耐药性现状分析

乳酸菌中的许多种类都是食品工业中常用的发酵菌种,但其耐药性会给食品安全带来风险。本文就乳酸菌的耐药机制、敏感性检测方法及发酵食品中乳酸菌的耐药现状和耐药转移性进行分析,为同行研究者能准确找出问题切入点提供资料。