霍乱肠毒素B亚单位在转基因番茄中表达的研究

将霍乱肠毒素B亚单位（CT－B）基因及内质网引导序列（SEKDEL）克隆到质粒pRTL2和pBI121中,分别构建植物双元表达载体pBI-CTB和pBI-CTBK,CT-B基因由Ca35S启动子控制表达。采用叶盘法经根癌农杆菌介导转化番茄（金丰1号,Jinfeng1)各表达载体得到一批转基因植株。经PCR和Southern blot分析表明CT－B基因整合到了番茄基因组中;ELISA和Western blot分析表明pBI-CTB和pBI-CTBK的转基因植株能够有效表达CT－B多肽,分别占番茄叶片可溶性蛋白的0.055%和0.084%。     

用寡核苷酸本身作为PCR引物检测其重组DNA

以待检测的寡核苷酸本身作为一个引物,加上两个载体特异引物,组成两对PCR引物。含待检测寡核苷酸片段的重组DNA用这两对引物可分别扩增出两个大小不同的片段,而载体DNA只有一对引物（即载体特异引物）可扩增出一个较小的片段。     

An expression profile of human α-lactalbumin in the milk of transgenic mouse

a-lactalbumin(a-Lac),amajorwheyprotein,isacalciummetalloprotein,thathasbeenfoundinallmilksstudiedsofar.ItinteractswithUDP-galactosyl-transferasetoformthelactosesynthetaseandthusmightbeakeyproteinforlactogenesis.Lactosesyn-thetaseispostulatedtobetherate-limitingenzymeforlactosebiosynthesis.Theincreaseda-Lacactivitycanproducesufficientlactosesynthetaseforthesynthesisoflactose,andinmilkyieldbydrawingwaterintomilk,sincelactoseisanosmoreactivemolecule.Transgenicswineoverexpressingbovinea-lactalbu…     

Urimem,a membrane that can store urinary proteins simply and economically,makes the large-scale storage of clinical samples possible

By nature,biomarker is the measurable change associated with a physiological or pathophysiological process.Unlike blood which has mechanisms to minimize changes and to keep the internal environment homeostatic,urine is more likely to reflect changes of the body and is a better biomarker source.Because of its potential in biomarker discovery,urinary proteins should be preserved comprehensively as the duration of the patients’corresponding medical records.Here,we propose a method to adsorb urinary proteins onto a membrane we named Urimem.This simple and inexpensive method requires minimal sample handling,uses no organic solvents,and is environmentally friendly.Urine samples were filtered through the membrane,and urinary proteins were adsorbed onto the membrane.The proteins on the membrane were dried and stored in a vacuum bag,which keeps the protein pattern faithfully preserved.The membrane may even permit storage at room temperature for weeks.Using this simple and inexpensive method,it is possible to begin preserving urine samples from all consenting people.Thus,medical research especially biomarker research can be conducted more economically.Even more objective large-scale prospective studies will be possible.This method has the potential to change the landscape of medical research and medical practice.     

Single-seeded InDel fingerprints in rice:An effective tool for indica-japonica rice classification and evolutionary studies

Asian cultivated rice(Oryza sativa L.),an important cereal crop worldwide,was domesticated from its wild ancestor 8000 years ago.During its long-term cultivation and evolution under diverse agroecological conditions, Asian cultivated rice has differentiated into indica and japonica subspecies.An effective method is required to identify rice germplasm for its indica and japonica features,which is essential in rice genetic improvements.We developed a protocol that combined DNA extraction from a single rice seed and the insertion/deletion(InDel) molecular fingerprint to determine the indica and japonica features of rice germplasm.We analyzed a set of rice germplasm,including 166 Asian rice varieties,two African rice varieties,30 accessions of wild rice species,and 42 weedy rice accessions,using the single-seeded InDel fingerprints(SSIF).The results show that the SSIF method can efficiently determine the indica and japonica features of the rice germplasm.Further analyses revealed significant indica and japonica differentiation in most Asian rice varieties and weedy rice accessions.In contrast,African rice varieties and nearly all the wild rice accessions did not exhibit such differentiation.The pattern of cultivated and wild rice samples illustrated by the SSIF supports our previous hypothesis that indica and japonica differentiation occurred after rice domestication under different agroecological conditions.In addition,the divergent pattern of rice cultivars and weedy rice accessions suggests the possibility of an endoferal origin(from crop)of the weedy rice included in the present study.     

Activation of STAT3 stimulates AHSP expression in K562 cells

Studies on the chaperone proteinα-hemoglobin stabilizing protein(AHSP)reveal that abundant AHSP in erythroid cells enhance the cells’tolerance to oxidative stress imposed by excessα-hemoglobin in pathological conditions.However,the potential intracellular modulation of AHSP expression itself in response to oxidative stress is still unknown.The present study examined the effect and molecular mechanism of STAT3,an oxidative regulator,on the expression of AHSP.AHSP expression increased in K562 cells upon cytokine IL-6-induced STAT3 activation and decreased in STAT3 knock-down K562 cells.Regulation of AHSP in oxidative circumstance was then examined inα-globin-overloaded K562 cells,and real-time PCR showed strengthened expression of both AHSP and STAT3.ChIP analysis showed binding of STAT3 to AHSP promoter and binding was significantly augmented with IL6 stimulation and uponα-globin overexpression.Dual luciferase reporter assays of the wildtype and mutated SB3 element,an IL-6RE site,in the AHSP promoter in K562 cells highlighted the direct regulatory effect of STAT3 on AHSP gene.Finally,direct binding of STAT3 to SB3 site of AHSP promoter was confirmed with EMSA assays.Our work reveals an adaptive AHSP regulation mediated by the redox-sensitive STAT3 signaling pathway,and provides clues to the therapeutic strategy for AHSP enhancement.     

展望21世纪的生命科学

对本世纪以来发展迅猛异常的生物科学的概况,特别是近对二三十年来,在分子生物学的带动下,生命科学在结构分子生物学;中心法则及其后的生物学细节研究;基因表达、调控和发育生物学;基因组计划和应用生物学及生物技术的发展;宏观生物学等方面讨论了生命科学的发展和特点,并从四个主要方面对２１世纪生命科学（包括生物技术）的发展趋势进行了预测,以达到综览生命科学全局,明确今后发展方向的目的。     

巴西人参化学成分和药理活性研究进展

巴西人参原产于南美洲,当地人把它当做具有壮阳、增强体质等作用的草药。巴西人参已在我国广西、浙江等地引种栽培成功,现代研究发现,其主要含有三萜和三萜皂苷类、甾体类等多种化学成分,具有抗肿瘤、抗炎、保护胃黏膜等药理活性。本文通过对近年来巴西人参的研究情况进行综述,阐明已有的化学物质基础和药理作用,为其进一步的深入研究和开发提供理论依据。     

金鱼草（Antitthinum majus L．）下胚轴外植体不定芽的高频再生

本文发展的技术可以使金鱼草下胚轴外植体不定芽高频再生。添加有２ｍｇ／ｌＢＡＰ和０．５ｍｇ／ｌＮＡＡ的ＭＳ培养基上再生芽出得又快又多，淡黄色愈伤组织易于形成并存活。但主要依赖的是６－ＢＡＰ。ＭＳ培养基中含有０．１ｍｇ／ｌ或６ｍｇ／ｌ浓度的６－ＢＡＰ均能刺激芽的发育，最适浓度为２－３ｍｇ／ｌ．仅加２，４－Ｄ，也能形成正常的黄色愈伤组织。但这样形成的愈伤组织在只含有０．１－６ｍｇ／ｌ６－ＢＡＰ或含有２ｍｇ／ｌ６－ＢＡＰ和０．５ｍｇ／ｌＮＡＡ的ＭＳ培养基上均不能分化生出再生芽来。仅加ＮＡＡ，能够刺激下胚轴形成根。加入ＡｇＮＯ＿３，则抑制不定芽的再生，并导致整个外植体变成棕色而死亡。组织化学分析结果表明：不定芽的再生源于下胚轴外植体表皮细胞。在不含有任何生长调节剂的ＭＳ培养基上，再生苗均能形成根。再生植株移栽至花盆可开花结实。     

Cryo-electron microscopy reveals high-resolution structures of 30-nm chromatin fibers in vitro

<正>Human chromosomes are the largest and most visible structures involved in the transfer of genetic information.The most striking property of a chromosome is that about three billion base pairs of the human genome are compacted into a nucleus of only several micrometers in diameter.It is well known that DNA in eukaryotic cells is initially packaged into nucleosomes by means of extensive association