网络仿真实验系统的研究与实现

本文综合利用Sniffer协议分析技术,开发出一套高效实用的计算机网络实验系统.在构建一种新的基于Sniffer计算机网络协议分析模型上,系统通过截获各种协议数据包来实现计算机网络协议的分析,并在协议分析的基础上确定网络故障、病毒等,给出了常用的网络实验的主要内容及使用的主要工具,并对其中的一个实验进行了详细说明.     

基于XML的油田WebGIS的设计与实现

石油的勘探开采均与地理信息密切相关,目前全国各大油田更多的采用国外一些现成的GIS平台,这些平台不但价格昂贵,而且很难实现与油田信息的无缝集成。为此,在对SVG、XML以及WebGIS等相关技术研究的基础上,设计并实现了一个基于XML的轻型油田WebGIS平台,对平台构架及实现过程中涉及的关键技术进行了重点研究。与传统的WebGIS系统相比,它具有速度快、交互性强、易扩展、个性化等特点。     

A synthetic naringenin derivative, 5-hydroxy-7,4'-diacetyloxyflavanone-N-phenyl hydrazone (N101-43), induces apoptosis through up-regulation of Fas/FasL expression and inhibition of PI3K/Akt signaling pathways in non-small-cell lung cancer cells

Naringenin, a well-known naturally occurring flavonone, demonstrates cytotoxicity in a variety of human cancer cell lines; its inhibitory effects on tumor growth have spurred interest in its therapeutic application. In this study, naringenin was derivatized to produce more effective small-molecule inhibitors of cancer cell proliferation, and the anticancer effects of its derivative, 5-hydroxy-7,4'-diacetyloxyflavanone-N-phenyl hydrazone (N101-43), in non-small-cell lung cancer (NSCLC) cell lines NCI-H460, A549, and NCI-H1299 were investigated. Naringenin itself possesses no cytotoxicity against lung cancer cells. In contrast, N101-43 inhibits proliferation of both NCI-H460 and A549 cell lines; this capacity is lost in p53-lacking NCI-H1299 cells. N101-43 induces apoptosis via sub-G1 cell-cycle arrest in NCI-H460 and via G0/G1 arrest in A549 cells. Expression of apoptosis and cell-cycle regulatory factors is altered: Cyclins A and D1 and phospho-pRb are down-regulated, but expression of CDK inhibitors such as p21, p27, and p53 is enhanced by N101-43 treatment; N101-43 also increases expression levels of the extrinsic death receptor Fas and its binding partner FasL. Furthermore, N101-43 treatment diminishes levels of cell survival factors such as PI3K and p-Akt dose-dependently, and N101-43 additionally induces cleavage of the pro-apoptotic factors caspase-3, caspase-8, and poly ADP-ribose polymerase (PARP). Cumulatively, these investigations show that the naringenin derivative N101-43 induces apoptosis via up-regulation of Fas/FasL expression, activation of caspase cascades, and inhibition of PI3K/Akt survival signaling pathways in NCI-H460 and A549 cells. In conclusion, these data indicate that N101-43 may have potential as an anticancer agent in NSCLC.     

大白菜低温胁迫转录因子BcICE1的克隆及表达分析

本研究采用RT-PCR结合SON-PCR技术从大白菜(Brassica pekinens)中分离了BcICE1基因的cDNA序列(GenBank登录号为HQ902162).该基因全长1 591 by,含有一个1494 by长的开放阅读框,编码497个氨基酸.序列比对表明,该蛋白C端含有一个典型的bHLH结构域,与其他植...     

两种苹果砧木及其嫁接苗生长差异比较

研究了八棱海棠、平邑甜茶的实生苗及其嫁接苗的生长差异,以确认其在苹果苗木培育中的作用差别.结果表明,八棱海棠实生苗具有较复杂的形态多样性,且生长一致性不如平邑甜茶;而八棱海棠的嫁接苗则有更好的一致性,但其生长却稍逊于平邑甜茶嫁接苗.因而实现砧木品种化则显得尤为重要.     

Potent in vivo antifungal activity against powdery mildews of pregnane glycosides from the roots of Cynanchum wilfordii

Two new pregnane glycosides, kidjoranine 3-O-β-D-glucopyranosyl-(1 → 4)-β-D-glucopyranosyl-(1 → 4)-α-L-cymaropyranosyl-(1 → 4)-β-D-cymaropyranosyl-(1→4)-α-L-diginopyranosyl-(1 → 4)-β-D-cymaropyranoside (5) and caudatin 3-O-β-D-glucopyranosyl-(1 → 4)-β-D-glucopyranosyl-(1 → 4)-α-L-cymaropyranosyl-(1 → 4)-β-D-cymaropyranosyl-(1 → 4)-α-L-diginopyranosyl-(1 → 4)-β-D-cymaropyranoside (6), were isolated from the roots of Cynanchum wilfordii along with four known compounds (1-4). The antifungal activities of the six compounds against barley powdery mildew caused by Blumeria graminis f. sp. hordei were compared to the antifungal activity of polyoxin B. The caudatin glycosides (1, 4, and 6) showed stronger antifungal activities than polyoxin B, whereas kidjoranine glycosides (2, 3, and 5) had weaker activities than polyoxin B. A wettable powder-type formulation (C. wilfordii-WP20) of the ethyl acetate extract from C. wilfordii roots prohibited the development of barley powdery mildew much more effectively than the commercial fungicide polyoxin B-WP10. In addition, C. wilfordii-WP20 effectively controlled strawberry powdery mildew caused by Sphaerotheca humuli under greenhouse conditions. Thus, the crude extract containing the pregnane glycosides can be used as a botanical fungicide for the environmentally benign control of powdery mildews.     

Development of an enzyme-linked immunosorbent assay based a monoclonal antibody for the detection of pyrethroids with phenoxybenzene multiresidue in river water

A sensitive and broad class selective direct competitive enzyme-linked immunosorbent assay (ELISA) using monoclonal antibody (McAb) has been described for the detection of pyrethroids with phenoxybenzene group. One monoclonal antibody, 2G(2)E(7), was obtained and characterized after fusion of myeloma cells with spleen cells isolated from BALB/c mice. The assay with the most selectivity for the family pyrethroids with phenoxybenzene group was optimized. The IC(50) values of the optimized immunoassay were 1.8 μg L(-1) for deltamethrin, 1.5 μg L(-1) for cypermethrin, 2.0 μg L(-1) for fluvalinate and fenvalerate, 2.2 μg L(-1) for phenothrin, 2.4 μg L(-1) for flucythrinate, 3.0 μg L(-1) for fenpropathrin, and 5.0 μg L(-1) for permethrin. River water samples fortified with pyrethroids were analyzed with the ELISA to evaluate the accuracy of the assay. The recoveries of pyrethroids in spiked water samples ranged from 74 to 108%. The results indicate that the ELISA developed can accurately simultaneously determine pyrethroids with phenoxybenzene group in water samples.     

Structural properties of hydrolyzed high-amylose rice starch by α-amylase from Bacillus licheniformis

High-amylose cereal starch has a great benefit on human health through its resistant starch (RS) content. Enzyme hydrolysis of native starch is very helpful in understanding the structure of starch granules and utilizing them. In this paper, native starch granules were isolated from a transgenic rice line (TRS) enriched with amylose and RS and hydrolyzed by α-amylase. Structural properties of hydrolyzed TRS starches were studied by X-ray powder diffraction, Fourier transform infrared, and differential scanning calorimetry. The A-type polymorph of TRS C-type starch was hydrolyzed faster than the B-type polymorph, but the crystallinity did not significantly change during enzyme hydrolysis. The degree of order in the external region of starch granule increased with increasing enzyme hydrolysis time. The amylose content decreased at first and then went back up during enzyme hydrolysis. The hydrolyzed starches exhibited increased onset and peak gelatinization temperatures and decreased gelatinization enthalpy on hydrolysis. These results suggested that the B-type polymorph and high amylose that formed the double helices and amylose-lipid complex increased the resistance to BAA hydrolysis. Furthermore, the spectrum results of RS from TRS native starch digested by pancreatic α-amylase and amyloglucosidase also supported the above conclusion.     

Purification and biochemical characterization of insoluble acid invertase (INAC-INV) from pea seedlings

Invertase (EC 3.2.1.26) catalyzes the hydrolysis of sucrose into D-glucose and D-fructose. Insoluble acid invertase (INAC-INV) was purified from pea (Pisum sativum L.) by sequential procedures entailing ammonium sulfate precipitation, ion exchange chromatography, absorption chromatography, reactive green-19 affinity chromatography, and gel filtration. The purified INAC-INV had a pH optimum of 4.0 and a temperature optimum of 45 °C. The effects of various concentrations of Tris-HCl, HgCl(2), and CuSO(4) on the activities of the purified invertase were examined. INAC-INV was not affected by Tris-HCl and HgCl(2). INAC-INV activity was inhibited by 6.2 mM CuSO(4) up to 50%. The enzymes display typical hyperbolic saturation kinetics for sucrose hydrolysis. The K(m) and V(max) values of INAC-INV were determined to be 4.41 mM and 8.41 U (mg protein)(-1) min(-1), respectively. INAC-INV is a true member of the β-fructofuranosidases, which can react with sucrose and raffinose as substrates. SDS-PAGE and immunoblotting were used to determine the molecular mass of INAC-INV to be 69 kDa. The isoelectric point of INAC-INV was estimated to be about pH 8.0. Taken together, INAC-INV is a pea seedling invertase with a stable and optimum activity at lower acid pH and at higher temperature than other invertases.     

黄土丘陵区小流域尺度上土壤有机碳空间异质性

通过对上黄试区小流域不同土地利用类型下的60个样点的采样分析,结合地统计学原理对小流域土壤有机碳的空间异质性进行研究。试验结果表明,土壤有机碳含量随土层深度的增加而减少,不同土地利用类型下的土壤有机碳存在显著性差异。表层0-10cm的土壤有机碳含量为9.544g/kg,明显高于10-30cm的7.10g/kg和30-60cm的4.63g/kg。通过Kriging插值法估算,其结果也表现出相同的规律。由土壤有机碳含量分布图可知,0-10cm,10-30cm和30-60cm 3层土壤的有机碳含量均表现出天然草地和柠条纯林高于川台地和河滩地。土壤有机碳含量在空间分布上表现出的特征,与动植物在土体中的垂直分布格局、人类社会活动及区域气候条件等因素有关。