三羟异黄酮对HER-2/neu高表达乳腺癌细胞血管生成相关因子表达的影响

三羟异黄酮(genistein)是大豆中的一种非营养成分,其结构与黄酮化合物类似,能竞争性地与雌激素受体结合,故称之为植物雌激素(phytoestrogen)。它具有广泛的生物学作用,如抗肿瘤、抗病毒、抗真菌、抗氧化、抗突变、抗高血压、抗增生等,其中genistein抑制肿瘤的血管生成是当前研究的热点之一。肿瘤的血管生成是肿瘤进一步生长转移的基础,该过程受肿瘤细胞和血管内皮细胞分泌的血管生成相关因     

Water-use efficiency of a mallee eucalypt growing naturally and in short-rotation coppice cultivation

This study compared mature Eucalyptus kochii subsp. plenissima trees in inner regions or edges of natural bushland to young trees belt-planted through cleared agricultural land as uncut saplings or regenerating coppice over 2.7 years at Kalannie, Western Australia (320 mm annual rainfall). We assessed the ability of the species to alter its gas exchange characteristics, leaf physical attributes, and water-use efficiency of foliar carbon assimilation (WUE _i) or of total dry matter production (WUE _DM). Stomatal conductance (g _s) varied five-fold between treatment means, with coppices exhibiting greatest values and mature bush least. Photosynthetic rates followed this trend. Leaf photosynthetic capacity estimated by chlorophyll content varied 1.3-fold parallel with variations in leaf thickness, with coppices rating lowest and mature edge trees most highly. WUE _i varied 1.5-fold between treatments and was greatest in mature inner-bush and edge trees. Leaf photosynthetic capacity and g _s were both correlated with WUE _i. Carbon isotope composition (δ¹³C values) of new shoot dry matter produced early in a seasonal flush were similar to those of root starch but when averaged over the whole season correlated well with WUE _i and gas exchange characteristics of trees of each treatment. Coppices showed poorest WUE _i and most negative shoot tip δ¹³C but their WUE _DM was high. This discrepancy was suggested to relate to carbon allocation strategies in coppices favouring fast growth of replacement shoots but not of roots. Physiology of coppice growth of E. kochii is usefully geared towards both rapid and water-use efficient production of woody biomass in water limited environments.     

果蝇多线染色体β异染色质区的螺旋结构(简报)

从1973年发现核小体至今,研究者们对染色质纤维结构和这种纤维组织成染色体的方式进行了广泛而深入的研究。由DNA到核小体到30nm染色质纤维几乎公认是按螺旋方式集缩的,但是有关30nm左右染色质纤维如何压缩形成染色体的高层次结构还没有统一的意见。关于这方面的研究目前已有许多模型。其中,Bak等提出的多级螺旋     

抗人肝癌单抗片段抗体HAb18F(ab')_2的冻干工艺研究

选择适合于HAb18F(ab')2片段抗体的冻干保护剂及其冻干工艺,是确保该生物制品的质量关键之一,对不同种类和不同浓度的保护剂进行了研究,结果表明10%蔗糖对HAb18F(ab')2片段抗体冻干样品的剂型、外观、残水量(<3%)、复溶时间(<10s)、纯度(>95%)及稳定性没有影响。研究优化与保护剂相结合的适用于HAb18F(ab')2片段抗体的最佳冻干工艺,为抗体片段扩大生产提供依据。     

Somatic embryogenesis and plantlet regeneration in mango (Mangifera indica L.)

Summary The ‘Carabao’ or ‘Manila Super’ mango (Mangifera indica L.), a virtually neglected fruit before the advent of KNO₃ flower induction in the early 1970s, is now the third leading Philippine export fruit after banana and pineapple. To apply biotechnology for improvement, a reliable embryogenesis and regeneration protocol is required. We have developed a protocol for somatic embryogenesis and plantlet regeneration in mango: eight strains of ‘Carabao’ and two unidentified varieties, PHL 12384 and PHL 12378. Over 40 batches of nucellar explants from immature fruis (0.75–5.0 cm long) were cultured in vitro from April 1999 to April 2000. Two media were used, MMSE. Mango Medium for Somatic Embryo Induction, Proliferation and Germination and MMPR, Mango Medium for Plantlet Regeneration. These are now routinely used. The protocol is reproducible in 14 other varieties of mango. Shifting the base medium from Gamborg's B5 medium to our own formulation. BP medium (Barba and Pate?a's formulation) effectively controlled browning. Browning has limited the successful in vitro culture of many woody species including the mango. Crop Science Society of the Philippines (CSSP) 2001 Best Paper Award, Asian Agriculture Congress, Westin Philippine Plaza, Manila, Philippines, April 24–27, 2001 and Philippine Fruit Association 2000 Best Poster Award, 8th National Symposium. PCARRD, Los Ba?os, Laguna, Philippines, November 14–16, 2000.     

玉米幼苗地上部/根间氮的循环及其基因型差异

以两个玉米（ZeamaysL.）自交系原引1号（YY1）和综31（Z31）为研究材料,采用盆栽土培的培养方法,在正常供氮（HN,0.15gN/kg干土）和低氮量供应（LN,0.038gN/kg干土）培养条件下对玉米幼苗植株体内氮的循环量及其在地上部/根间的分配量进行了定量地测定、计算。结果表明,在玉米幼苗地上部/根间氮的循环量很高。低氮量供应使玉米幼苗植株吸氮量下降,根中氮的分配比例增加,同时地上部/根间氮的循环量也随之减少。与氮低效自交系Z31相比,氮高效自交系YY1幼苗中地上部/根间的氮循环量大、氮向根的分配量高,因而有利于其根系的生长,表现为根/地上部之比和总根长较高。这可能有利于其中后期对氮素的高效吸收与利用。     

依赖于微环境的TGFβ信号

转化生长因子β（transforming growth factor β，TGFβ）家族成员是一类分泌的细胞因子，在胚胎发育、免疫调节、伤口修复、细胞增殖和抑制等过程中发挥重要作用。其中,TGFβ1、TGFβ2和TGFβ3在进化上最晚出现，并以潜伏态分泌。有别于家族中的大多数成员，TGFβ1-3的信号具有时空区域性，并依赖于其所处的微环境。阐明依赖于微环境的TGFβ信号的多层次调控机制对于理解TGFβ信号在免疫、癌症等生理、病理条件下的功能，以及开发临床治疗策略具有重要意义。本文从TGFβ前体复合物的结构入手，并从TGFβ的激活，配体-受体识别，跨膜信号传导及转录调控等方面，论述依赖于微环境的TGFβ信号的调控机制，同时讨论肿瘤微环境中多效的TGFβ信号，进而对今后的研究方向进行展望。