用RAPD法研究火炬松愈伤组织发生的遗传特性(英文)

体外培养对于植物的快速繁殖是非常有效的。和其它一些松果类硬木植物一样,火炬松的体外培养成功率却一直很低。本工作研究了不同的基本培养基和低温条件对于火炬松Ｊ－５６, Ｓ－１００３, ａｎｄ Ｅ－４４０等三个品系的成熟合子胚形成愈伤组织、分化出芽、成苗的影响。在不同的基本培养基条件下芽分化的程度差异很大。合子胚经过９－１２周培养,开始分化,形成具有器官发生的愈伤组织（Ｆｉｇ．２ａ）。分化后３周,开始诱导出芽（Ｆｉｇ．２ｂ）,芽的生长快慢不同（Ｆｉｇ．２ｃ,ｄ）。同一个愈伤组织上会生出几个芽来（Ｆｉｇ．２ｅ）。在添加有ＩＢＡ和ＢＡ的ＴＥ培养基上芽生长最快（Ｆｉｇ．１）。低温条件持续 １５天,能增加芽的数量和分化的程度（Ｔａｂｌｅ１）。上述培养基中增加ＧＡ３时表明,ＧＡ３对于根的诱导有决定性的作用。将９８株再生苗转移到特殊的混合土壤上;成活了７５株苗（Ｆｉｇ．２ｆ）。以这三种火炬松的再生苗尖为材料制备ＤＮＡ。用２０个引物进行ＲＡＰＤ分析,结果表明：这三种火炬松苗的扩增产物是相同的（Ｆｉｇ．２ｇ,ｈ＆ｉ）。这说明：用愈伤组织克隆植株的过程中没有引起植物遗传变异。     

公平贸易引发的是一连串的问号

<正>本期封面题目或许有些生僻,实则与世人皆不无关系。四川安龙村七户农民为成都部分消费者预定种植和配送生态蔬菜,贵州流芳村农民协会在全村推广种植和外销无证的有机稻,内蒙古阿拉善盟牧民合作社在努力把极干旱地区的稀品驼肉和驼绒推上市场,云南景迈山的古茶园在普洱茶价格暴涨暴跌中的奇特经历,贵州白兴村的手工刺绣在市场上的两难境遇,部分北京市民在郊区"小毛驴"农场当起菜农为自己种菜……类似本期所讲述的这些故事,想必在全国不止成百上千。而从这     

肿瘤易感基因BRCA1

ＢＲＣＡ１为一新的肿瘤易感基因，定位在１７ｑ２１，其ｃＤＮＡ可转录７．８ｋｂｍＲＮＡ，编码含１８６３个氨基酸残基的长多态，在遣传性乳腺卵巢癌中有高频率的ＢＲＣＡ１基因杂合性丢失，同时有多形式多位点的基因突变，符合肿瘤抑制基因特点。     

An integrated database on ticks and tick-borne zoonoses in the tropics and subtropics with special reference to developing and emerging countries

Tick-borne zoonoses (TBZ) are emerging diseases worldwide. A large amount of information (e.g. case reports, results of epidemiological surveillance, etc.) is dispersed through various reference sources (ISI and non-ISI journals, conference proceedings, technical reports, etc.). An integrated database-derived from the ICTTD-3 project ( http://www.icttd.nl )-was developed in order to gather TBZ records in the (sub-)tropics, collected both by the authors and collaborators worldwide. A dedicated website ( http://www.tickbornezoonoses.org ) was created to promote collaboration and circulate information. Data collected are made freely available to researchers for analysis by spatial methods, integrating mapped ecological factors for predicting TBZ risk. The authors present the assembly process of the TBZ database: the compilation of an updated list of TBZ relevant for (sub-)tropics, the database design and its structure, the method of bibliographic search, the assessment of spatial precision of geo-referenced records. At the time of writing, 725 records extracted from 337 publications related to 59 countries in the (sub-)tropics, have been entered in the database. TBZ distribution maps were also produced. Imported cases have been also accounted for. The most important datasets with geo-referenced records were those on Spotted Fever Group rickettsiosis in Latin-America and Crimean-Congo Haemorrhagic Fever in Africa. The authors stress the need for international collaboration in data collection to update and improve the database. Supervision of data entered remains always necessary. Means to foster collaboration are discussed. The paper is also intended to describe the challenges encountered to assemble spatial data from various sources and to help develop similar data collections.     

Novel 9a,11-bridged azalides: One-pot synthesis of N'-substituted 2-imino-1,3-oxazolidines condensed to an azalide aglycone

An efficient one-pot method for the synthesis of novel 9a,11-bridged 15-membered 9a-aza-9-deoxo-9a-homoerythromycin A and its 6-O-methyl analogue has been developed. The novel bicyclic azalide scaffold is characterized by an N′-substituted-2-imino-1,3-oxazolidine moiety bound to a macrolactone ring between positions 9a and 11. Removal of the cladinose sugar from the starting compounds allows easy preparation of a small series of such bicyclic 3-keto and 3,6-hemiketal azalide derivatives. A mechanism for the formation of N′-substituted-2-imino-1,3-oxazolidines is discussed. Antibacterial properties of the prepared compounds were evaluated.     

日利用l基因工程培育成功耐高温植物

Nature Biotechnology 2000年18卷3期249页报道：日本九州大学的科学家们已培育成功一种可在高温下维持光合作用的转基因烟草(Science287,476～479,2000)。鉴于沙漠植物的叶绿体可在高温下减少三烯脂肪酸的合成,科学家们培育了含有来自拟南芥(Arabidopsis thaliana)的附加的叶绿体特异△-3去饱和酶(脱氢酶)基因的两个转基因烟草株系。互阻遏作用导致△-3去饱和酶基因在这些植株中的表达下降,以及与此伴随的三烯脂肪酸的相应减少。因此,这种转基因植株40℃高温下的光合作用活性可高于25℃下的活性(但40℃可极大地降低野生型植株的光合作用强度)。科学家们提示,利用内源基因可避免利－46用外源DNA进行基因操作时发生的有害效应。这个研究组的植物生理学家KohIba说：“此项研究给予我们的启迪是,利用基因操作技术可育成新的农作物或树木,以适应无可避免的全球性气候变化。例如可使寒冷地区的树木适应于高温环境”。汪开治     

应用基因工程技术生产IL-11和IL-12

目前武汉大学生命科学学院科研人员针对人体失血和免疫功能下降,应用基因工程技术生产出了人白细胞介素-11(即IL-11)和人白细胞介素-12(即IL-12)。 1 IL-11为人体自然产生的细胞生长因子,能增加血小板,提高凝血速度,防止伤口出血不止,在临床上用来治疗低血小板症,还能辅助治疗癌症,主要用于化疗。克隆于载体,通过大肠杆菌充分表达,经分离、纯化和精制,生产出质量很高的医用成药,故疗效很好。 2 IL-12这是目前在细胞素中发现对人体免疫活性细胞诱导和调节最强、范围最广的一种。其研制技术是将IL-12的两种不同来源的基因克隆于昆虫病毒载体,在昆虫细胞内表达,经分离纯化成工程蛋白,再制备成医药产品。它能诱导干扰素的产生,激活T细胞和NK细胞产生肿瘤坏死因子,能抗利什曼原虫、疟原虫、结核杆菌、血吸虫、肿瘤和病毒及其各相应的疾病,故美国基因研究所和惠施-阿耶斯特制药公司将它用于治疗艾滋病和肿瘤病,效果很好。秦春圃