苦杏仁精油对粘虫的触杀活性研究

以粘虫4龄幼虫为对象,采用"点滴法"研究了山杏种仁两种苦杏仁精油(含HCN和去HCN)对粘虫的触杀活性及其生长发育的影响.结果显示,处理后48 h,5～100 μL/mL浓度处理的试虫死亡率均在51.67%以上,40和100 μL/mL浓度处理的粘虫死亡率分别达到了95%(含HCN)/98.33%(去HCN)和100%,48 h时含HCN与除去HCN两种苦杏仁精油对粘虫的触杀致死中浓分别为5.10和4.69 μL/mL;苦杏仁精油对粘虫的化蛹期以及羽化期提前1～3 d,并有一定数量的畸形蛹出现,部分试虫虽能正常化蛹并羽化,但其蛹以及成虫虫体均较对照小,且羽化后蛾体萎缩,活动力降低,因展翅困难而死.可见,两种苦杏仁精油对粘虫具有很强的触杀活性,且去HCN的苦杏仁精油对粘虫的活性高于含HCN的苦杏仁精油,其对粘虫生长发育抑制活性主要表现化蛹期以及羽化期提前,苦杏仁精油有望发展为植物性杀虫剂.     

Enhancement of Astragalus polysaccharide on the immune responses in pigs inoculated with foot-and-mouth disease virus vaccine

The effects of Astragalus polysaccharides (APS) on the immune response in pigs immunized with foot-and-mouth disease virus (FMDV) vaccine were investigated. Fifteen pigs were randomly divided into five groups. Four groups were vaccinated with a FMDV inactivated vaccine. Pigs in three experimental groups were administered varying doses of APS (APS1, 5 mg/kg; APS2, 10 mg/kg; APS3, 20 mg/kg). The influence of APS on the number of CD3⁺CD4⁻CD8⁺ cytotoxic T cells, CD3⁺CD4⁺CD8⁺ T helper memory cells, and CD3⁻CD4⁻CD8⁺ natural killer cells among peripheral blood lymphocytes (PBL) in the three APS groups were significant compared to the vaccine group. In vitro stimulation of PBL by Con A and LPS in APS groups induced a stronger proliferative response at 2 and 6 weeks post-inoculation (PI). APS markedly increased the titer of FMDV-specific antibody in a dose-dependent manner, and up-regulated mRNA expression of IFN-γ and IL-6. APS could potentially be used as an immunomodulator for a FMDV vaccine and provide better protection against FMDV.     

Identification of diagnostic biomarkers for infection in premature neonates

Infection is a leading cause of neonatal morbidity and mortality worldwide. Premature neonates are particularly susceptible to infection because of physiologic immaturity, comorbidity, and extraneous medical interventions. Additionally premature infants are at higher risk of progression to sepsis or severe sepsis, adverse outcomes, and antimicrobial toxicity. Currently initial diagnosis is based upon clinical suspicion accompanied by nonspecific clinical signs and is confirmed upon positive microbiologic culture results several days after institution of empiric therapy. There exists a significant need for rapid, objective, in vitro tests for diagnosis of infection in neonates who are experiencing clinical instability. We used immunoassays multiplexed on microarrays to identify differentially expressed serum proteins in clinically infected and non-infected neonates. Immunoassay arrays were effective for measurement of more than 100 cytokines in small volumes of serum available from neonates. Our analyses revealed significant alterations in levels of eight serum proteins in infected neonates that are associated with inflammation, coagulation, and fibrinolysis. Specifically P- and E-selectins, interleukin 2 soluble receptor alpha, interleukin 18, neutrophil elastase, urokinase plasminogen activator and its cognate receptor, and C-reactive protein were observed at statistically significant increased levels. Multivariate classifiers based on combinations of serum analytes exhibited better diagnostic specificity and sensitivity than single analytes. Multiplexed immunoassays of serum cytokines may have clinical utility as an adjunct for rapid diagnosis of infection and differentiation of etiologic agent in neonates with clinical decompensation.     

杜鹃花科植物活性成分及作用机制研究进展

杜鹃花科(Ericaceae)植物约有54属,1700余种,分布极广,主产于南、北半球的温带和北半球的亚寒带。中国约有15属550余种,其中有毒品种9属100种以上,集中于金叶子属(Cribiodendron)、米饭花属(Lyonia)、马醉木属(Pieris)和杜鹃花属(Rhododendron)〔1〕。中国西南山区被认为是全国也是全世界的杜鹃花属分布中心,不少种被引种到欧美,成为当地著名庭园花卉的亲本〔2〕。杜鹃花科植物或具极高的欣赏价值,或有很高的药用价值,其广阔的开发应用前景已引起国内外的重视。笔者综述了近年来关于杜鹃花科植物活性成分、构效关系、生物活性及作用机制方…     

Expression and purification of the catalytic domain of human vascular endothelial growth factor receptor 2 for inhibitor screening

Vascular endothelial growth factor (VEGF), an endothelial cell-specific mitogen, can act in tumor-induced angiogenesis by binding to specific receptors on the surface of endothelial cells. One such receptor, VEGFR-2/KDR, plays a key role in VEGF-induced angiogenesis. Here, we expressed the catalytic domain of VEGFR-2 as a soluble active kinase using Bac-to-Bac expression system, and investigated correlations between VEGFR-2 activity and enzyme concentration, ATP concentration, substrate concentration and divalent cation type. We used these data to establish a convenient, effective and non-radioactive ELISA screening technique for the identification and evaluation of potential inhibitors for VEGFR-2 kinase. We screened 200 RTK target-based compounds and identified one (TKI-31) that potently inhibited VEGFR-2 kinase activity (IC50=0.596 microM). Treatment of NIH3T3/KDR cells with TKI-31 blocked VEGF-induced phosphorylation of KDR in a dose-dependent manner. Moreover, TKI-31 dose-dependently suppressed HUVEC tube formation. Thus, we herein report a novel, efficient method for identifying VEGFR-2 kinase inhibitors and introduce one, TKI-31, that may prove to be a useful new angiogenesis inhibitor.     

南瓜属4个栽培种种子蛋白质电泳分析

通过聚丙烯酰胺凝胶电泳(PAGE)对南瓜属4个栽培种中国南瓜、印度南瓜、美洲南瓜及黑籽南瓜的12个品种种子蛋白组分进行了分析。结果显示,黑籽南瓜种子以盐溶蛋白条带居多;其它3个栽培种以水溶蛋白条带居多,其次为盐溶蛋白;4个栽培种酸溶蛋白条带均较少;醇溶蛋白未分离得到蛋白谱带。水溶、盐溶、酸溶蛋白电泳图谱显示各栽培种间蛋白谱带差异明显,同一栽培种品种间蛋白谱带较为一致。     

Soil Properties and their Spatial Pattern in a Degraded Sandy Grassland under Post-grazing Restoration, Inner Mongolia, Northern China

In this study, we use classical and geostatistical methods to identify characteristics of some selected soil properties including soil particle size distribution, soil organic carbon, total nitrogen, pH and electrical conductivity and their spatial variation in a 5-year recovery degraded sandy grassland after two different grazing intensity disturbance: post-heavy-grazing restoration grassland (HGR) and post-moderately grazing restoration grassland (MGR), respectively, in Horqin steppe, Inner Mongolia, northern China. The objective was to examine effect of grazing intensity on spatial heterogeneity of soil properties. One hundred soil samples were taken from the soil layer 0–15 cm in depth of a grid of 10 m×10 m under each treatment. The results showed that soil fine fractions (very fine sand, 0.1–0.05 mm and silt + clay, <0.05 mm), soil organic carbon and total nitrogen concentrations were significant lower and their coefficients of variation significant higher under the HGR than under the MGR. Geostatistical analysis of soil heterogeneity revealed that soil particle size fractions, organic carbon and total nitrogen showed different degree of spatial dependence with exponential or spherical semivariograms on the scale measured under HGR and MGR. The spatial structured variance account for a large proportion of the sample variance in HGR plot ranging from 88% to 97% for soil particle fractions, organic C and total N, however, except for organic C (88.8%), the structured variance only account for 50% of the sample variance for soil particle fractions and total N in the MGR plot. The ranges of spatial autocorrelation for coarse-fine sand, very fine sand, silt + clay, organic C and total N were 13.7 m, 15.8 m, 15.2 m, 22.2 m and 21.9 m in HGR plot, respectively, and was smaller than in MGR plot with the corresponding distance of 350 m, 144.6 m, 45.7 m, 27.3 m and 30.3 m, respectively. This suggested that overgrazing resulted in an increase in soil heterogeneity. Soil organic C and total N were associated closely with soil particle fractions, and the kriging-interpolated maps showed that the spatial distribution of soil organic C and total N corresponded to the distribution patterns of soil particle fractions, indicating that high degree of spatial heterogeneity in soil properties was linked to the distribution of vegetative and bare sand patches. The results suggested that the degree of soil heterogeneity at field scale can be used as an index for indicating the extent of grassland desertification. Also, the changes in soil heterogeneity may in turn influence vegetative succession and restoration process of degraded sandy grassland ecosystem.