Endotoxin/lipopolysaccharide activates NF-kappa B and enhances tumor cell adhesion and invasion through a beta 1 integrin-dependent mechanism

Beta(1) integrins play a crucial role in supporting tumor cell attachment to and invasion into the extracellular matrix. Endotoxin/LPS introduced by surgery has been shown to enhance tumor metastasis in a murine model. Here we show the direct effect of LPS on tumor cell adhesion and invasion in extracellular matrix proteins through a beta(1) integrin-dependent pathway. The human colorectal tumor cell lines SW480 and SW620 constitutively expressed high levels of the beta(1) subunit, whereas various low levels of alpha(1), alpha(2), alpha(4), and alpha(6) expression were detected. SW480 and SW620 did not express membrane-bound CD14; however, LPS in the presence of soluble CD14 (sCD14) significantly up-regulated beta(1) integrin expression; enhanced tumor cell attachment to fibronectin, collagen I, and laminin; and strongly promoted tumor cell invasion through the Matrigel. Anti-beta(1) blocking mAbs (4B4 and 6S6) abrogated LPS- plus sCD14-induced tumor cell adhesion and invasion. Furthermore, LPS, when combined with sCD14, resulted in NF-kappaB activation in both SW480 and SW620 cells. Inhibition of the NF-kappaB pathway significantly attenuated LPS-induced up-regulation of beta(1) integrin expression and prevented tumor cell adhesion and invasion. These results provide direct evidence that although SW480 and SW620 cells do not express membrane-bound CD14, LPS in the presence of sCD14 can activate NF-kappaB, up-regulate beta(1) integrin expression, and subsequently promote tumor cell adhesion and invasion. Moreover, LPS-induced tumor cell attachment to and invasion through extracellular matrix proteins is beta(1) subunit-dependent.     

营养物质对桑黄菌丝生物量及胞外多糖产量的影响

研究了不同碳源、氮源和无机盐对桑黄深层培养菌丝生物量和胞外多糖产量的影响,结果表明：在培养温度为26℃、摇床转速为160r／min、发酵时间为10d的条件下,以桑黄菌丝生物量为指标,最适碳源、氮源和无机盐分别是果糖或葡萄糖、酵母粉或酵母膏、KH2P04或MgSO4·7H2O;菌丝生物量分别达到1．51、1．31、1．69、1．52、1．52、1．36g／100mL;以胞外多糖为指标,最适碳源、氮源和无机盐分别是葡萄糖、酵母膏、ZnSO4·7H2O,胞外多糖产量分别达到0．49、0．45、0．22g／100mL。     

Zn对细胞保护作用机理的研究

应用扫描质子微探针和同步辐射ｘ荧光分析技术测定了细胞中元素的分布和组成,为确定Zn是细胞结构成分提供了直接的实验依据.用上述核技术结合有关生化指标,分析测定了正常和损伤细胞（脂质过氧化损伤）中Fe,Zn和丙二醛、SH基含量变化的相互关系.实验结果表明,当细胞发生脂质过氧化损伤时,Fe含量和丙二醛含量同步增高,而Zn含量和SH基量则降低.给细胞补充Zn后,提高了细胞质膜中的Zn含量,SH基量也随之增加,同时丙二醛量降低.提示Zn保护细胞完整性的作用机理之一是控制脂质过氧化作用.Zn可保护膜蛋白的SH基,减少和阻止被Fe所催化的过氧化反应.     

黑麦草叶内游离脯氨酸含量对于不同类型和强度的水分胁迫的生理生态响应(英文)

实验植物黑麦草（Ｌｏｌｉｕｍｐｅｒｅｎｎｅ）种植于自行设计和制作的圆形土壤柱内,土壤含水量采用称重法加以控制,通过调节灌水次数和每次灌入水量模拟３种类型的水分胁迫,即周期性胁迫、持续稳定性胁迫和渐进性胁迫,并以充足灌水作为对照。３种胁迫又分别设有３个水平,即轻度、中度和重度。当土壤柱内植物建立稳定种群后开始胁迫处理,至生长季末共进行两个周期的胁迫实验。胁迫处理期间以固定间隔在草群内取最新完全展开的叶片测定其含水量和游离脯氨酸含量。实验结果表明,３种类型的水分胁迫均引起脯氨酸在植物叶内的积累且其数量随胁迫强度增加而变化,但这种效应是累积性的而不是即时性的。在任何一种处理的时间序列上,脯氨酸含量的变化与土壤含水量的变化不存在同步性,而与叶片含水量变化呈同步相反走势。通过与他人从生理生化角度所做的工作相比较,本文对上述研究结果的生理生态学意义进行了讨论。     

山楂蜂花粉中脂肪酸的GC-MS分析

用乙醇-氯仿作溶剂,提取出山楂蜂花粉粗脂肪,然后进行甲酯化处理,用气相色谱/质谱联用技术进行分离鉴定,共鉴定出10种脂肪酸,并测定相对含量,多不饱和脂肪酸含量较高,其中亚油酸相对含量为47.84%,亚麻酸相对含量为19.30%.     

The chromatin structure of specific genes: I. Evidence for higher order domains of defined DNA sequence.

When the chromatin of Drosophila is examined by digestion with DNAase I or micrococcal nuclease, no general structural organization above the level of the nucleosome is revealed by the cleavage pattern. In contrast, the DNAase I cleavage pattern of specific regions of the Drosophila chromosome shows discrete bands with sizes ranging from a few kilobase pairs (kb) to more than 20 kb. Visualization of such higher order bands was achieved by the use of the Southern blotting technique. The DNAase I-cleaved fragments were transferred onto a nitrocellulose sheet after size fractionation by gel electrophoresis. Hybridization was then carried out with radioactively labeled cloned fragments of DNA from D. melanogaster. For the five different chromosomal regions examined, each gives a unique pattern of higher order bands on the autoradiogram; the patterns are different for different regions. Restriction enzyme cleavage of the fragments generated indicates that the preferential DNAase I cleavage sites in chromatin are position-specific. The chromosomal regions bounded by preferential DNAase I cleavage sites are referred to as supranucleosomal or higher order domains for purposes of discussion and analysis. The micrococcal nuclease cleavage pattern of chromatin at specific loci was also examined. In the one case studied in detail, this nuclease also cleaves at position-specific sites.     

辽宁和江苏两省杂草稻植物性状多样性

辽宁和江苏两省是我国杂草稻(Oryza sativa f. spontanea)发生最为严重的地区之一, 为明确两省杂草稻识别特征和类型, 我们在两省14个市29个样点采集样品, 与当地栽培水稻品种一并在南京种植, 观测了营养生长期和生殖生长期的23个植物性状。结果表明, 两省杂草稻在营养生长期的1月株高、1月和2月分蘖数, 在生殖生长期的果皮色、谷粒长/宽比、百粒重、落粒性、秆硬度、剑叶宽、剑叶长、有效穗数、50%黄熟、50%黄熟–50%抽穗和全黄熟等性状与相应的当地栽培稻存在差异;主成分1和主成分2组成的二维散点图(累计贡献率达43.24%)也显示出两省杂草稻间以及与栽培稻间的差异性。采用欧氏距离对两省杂草稻进行系统聚类可以将杂草稻分为籼型和粳型。其中辽宁省杂草稻全部聚在粳型类群中, 它们又可细分为两类; 江苏省杂草稻既有粳型, 又有籼型, 其中粳型与辽宁省杂草稻聚在粳型类群中, 籼型又可分为3类。这6个类群分别具有如下突出特点: 第1类为强落粒、粒轻、秆矮、早熟、偏粳等; 第2类为无芒、穗多、强休眠、剑叶窄、偏粳等; 第3类为长芒、弱分蘖、穗少、弱落粒、偏粳等; 第4类为硬秆、剑叶宽、迟熟、强休眠、偏籼等; 第5类为红果皮、粒长、软秆、粒重、偏籼等; 第6类为无芒、株高、穗长、剑叶长、偏籼等。上述杂草稻的形态学指标和类型的研究将为两省开展杂草稻危害防治工作提供理论依据。     

地毯草黄单胞菌双组分系统VgrS-VgrR基因敲除及表型筛选

【目的】研究地毯草黄单胞菌双组分系统VgrS-VgrR与致病性的关系,为木薯细菌性病害的高效防控提供分子生物学证据。【方法】采用同源重组方法构建vgrS和vgrR的插入失活突变体,用可移动的cosmid载体p HM1构建互补菌株。检测突变体的致病性、细菌游动性、胞外酶、胞外多糖的变化,观察细菌对H_2O_2和金属离子胁迫的反应。【结果】相比野生型菌株,vgrS和vgrR突变体接种寄主植物木薯后致病力显著降低,突变体的游动性减少、蛋白酶活性减弱、H_2O_2耐受性降低,在高浓度金属离子Fe²⁺、Fe³⁺、Cu²⁺、Ni²⁺、Zn²⁺、Co²⁺的胁迫条件下菌体生长显著减弱。然而,vgrS和vgrR突变体的胞外多糖含量显著升高,分别是野生型的2.14和1.89倍。【结论】阐明了VgrS-VgrR系统在细菌致病过程中发挥的重要作用,为鉴定VgrS-VgrR调控机制提供线索,为药物筛选提供靶向目标。     

昆虫嗅觉感受细胞电反应计算机数据分析

昆虫嗅觉感受细胞电反应计算机数据分析吴锋,吴才宏（北京志同电子公司北京１０００８０）（北京大学生命科学学院北京１００８７１）昆虫触角电位和单个嗅觉感受细胞电反应记录已成为研究昆虫性信息素及化学通讯机制的重要手段。实验中要记录和分析处理大量数据。在所记...