萹蓄的化学成分研究

从药用植物蓄 (Polygonumaviculare)全草的丙酮提取物中分离鉴定了 10个化合物 ,经波谱学鉴定为 :山奈酚 (kaempferol) (1) ,槲皮素 (quercetin) (2 ) ,胡桃宁 (juglanin) (3) ,黄芪甙 (astragalin) (4) ,蓄甙 (avicularin) (5 ) ,槲皮甙 (quercetrin) (6 ) ,杨梅树皮甙 (myricitrin) (7) ,desmanthin 1(8) ,loliolide(9)和丁香脂素 (syringaresinol) (10 )。其中 ,化合物 (8) ,(9) ,(10 )为首次从该植物中分离得到。     

肾茶的化学成分

从肾茶 (Clerodendranthusspicatus)的地上部分共分离了 19个化合物 ,分别被鉴定为 5 羟基 7,3′ ,4′ 三甲氧基黄酮 (1) ,鼠尾草素 (2 ) ,5 羟基 6 ,7,3′ ,4′ 四甲氧基黄酮 (3) ,泽兰黄素 (4 ) ,3′ 羟基 5 ,7,8,4′ 四甲氧基黄酮 (5 ) ,异橙黄酮 (6 ) ,黄芪苷 (7) ,异槲皮素 (8) ,咖啡酸 (9) ,对 -羟基苯甲醛 (10 ) ,对 -羟基苯甲酸 (11) ,原儿茶醛 (12 ) ,原儿茶酸 (13) ,3,4 二羟基苯酰甲醇 (14 ) ,迷迭香酸 (15 ) ,迷迭香酸乙酯 (16 ) ,秦皮乙素(17) ,neoorthosipholA (18)和β 谷甾醇 (19)。迷迭香酸和其它酚性化合物可能与该植物的抗菌、消炎的药效有着直接的关系。     

基于SRAP分子标记的海南沼虾种群遗传多样性

为了调查我国海南沼虾(Macrobrachium hainanense)不同地理种群遗传多样性及遗传分化状况,本文采用序列相关扩增多态性(sequence-related amplified polymorphism,SRAP)标记对我国南方瓯江(OJ)、闽江(MJ)、珠江(PR)、万泉河(WQ)、昌化江(CH)等5个海南沼虾种群的遗传多样性进行了研究。共得到255个清晰、稳定的位点,平均多态位点比例为47.05%,由小到大依次为:PR(43.92%)=WQ(43.92%)相似文献   

唐古特瑞香的化学成分研究

从唐古特瑞香(Daphne tangutica Maxim)95%乙醇提取物石油醚部分分离得到14个化合物,通过波谱学方法鉴定为β-谷甾醇(1)、β-胡萝卜苷(2)、2,4-二羟基-3,6-二甲基苯甲酸甲酯(3)、蛇床子素(4)、植物醇(5)、软脂酸(6)、stigmast-5-ene-3β,7α-diol(7)、(-)-lariciresinol(8)、daphnetin(9)、daphnoretin(10)、(-)-丁香树脂醇(11)、( )-medioresinol(12)、daphnelicin(13)和咖啡酸二十二酯(14)。     

鬼针草中一个新的查耳酮甙

从鬼针草BidenspilosaL .地上部分的丙酮提取物中 ,分离鉴定了 1 8个化合物 ,其中包括一个新的查耳酮甙类化合物 (α,3,2′,4′ tetrahydroxy 2′ O β D glucopyranosylchalcone,2 )。其它化合物分别鉴定为butein (1 ) ,okanin 4 methylether 3′ O β glucoside (3) ,sulfuretin (4) ,6 ,7,3′,4′ tetrahydroxyaurone (5) ,海生菊苷 (maritimein ,6) ,(Z ) 6 O (6″ acetyl β D glucopyr anosyl) 6 ,7,3′,4′ tetrahydroxy aurone (7) ,(Z ) 6 O (4″,6″ diacetyl β D glucopyranosyl) 6 ,7,3′,4′ tetrahydroxy aurone (8) ,(Z ) 6 O (3″,4″,6″ triacetyl β D glucopyranosyl) 6 ,7,3′,4′ tetrahydroxy aurone (9) ,木犀草素 (luteolin ,1 0 ) ,槲皮素 (quercetin,1 1 ) ,异槲皮苷 (iso quercitrin,1 2 ) ,芦丁 (rutin,1 3) ,黄芪苷 (astragalin,1 4 ) ,quercetin 3,4′ dimethylether 7 O rutinoside (1 5) ,反式丁烯二酸 (1 6) ,2 β D glucopyranosyloxy 1 hydroxy trideca 3 ,5,7,9,1 1 pentayne (1 7)和 3 β D glucopyranosyloxy 1 hydroxy 6 (E ) tetradecene 8,1 0 ,1 2 triyne (1 8)。     

沙质草地3种优势植物叶片光合生理对增温和降水减少的响应北大核心CSCD

以沙质草地优势物种猪毛蒿、胡枝子和糙隐子草为研究对象,利用开顶式生长室(OTC)模拟增温,研究降水减少20%、40%和60%与增温的交互作用对3种典型植物叶片光合气体交换特征及叶绿素荧光特征的影响,以揭示沙质草地3种优势植物对气候变化的响应规律。结果显示:(1)与自然温度相比,OTC模拟增温增加了猪毛蒿C_(i),显著降低了胡枝子G_(s)、P_(n)和T_(r)、糙隐子草G_(s)和P_(n)、猪毛蒿WUE和L_(s),也显著降低了猪毛蒿和胡枝子F_(v)/F_(m)和F_(v)/F_(o)。(2)无论增温与否,随着降水减少幅度的增加,猪毛蒿G_(s)和P_(n)呈下降趋势,且中度以上的干旱胁迫下(降水减少>40%)胡枝子和糙隐子草P_(n)显著低于对照。(3)在自然温度条件下,轻度干旱胁迫时(降水减少20%)猪毛蒿T_(r)显著低于对照,重度干旱胁迫时(降水减少60%)其WUE、F_(v)/F_(m)和F_(v)/F_(o)显著低于对照;重度干旱胁迫时,胡枝子C_(i)显著高于对照,差异幅度达10.7%,L_(s)显著低于对照,轻度干旱胁迫时(降水减少20%)其F_(v)/F_(m)和F_(v)/F_(o)显著高于中度以上的干旱胁迫;中度以上的干旱胁迫下糙隐子草T_(r)和G_(s)显著低于对照,重度干旱胁迫时,其C_(i)、F_(v)/F_(m)和F_(v)/F_(o)显著低于对照,WUE和L_(s)显著高于对照。(4)增温与降水减少交互作用下,所有处理猪毛蒿C_(i)均高于对照,差异幅度分别达4.5%,6.0%和8.4%;胡枝子T_(r)均显著低于对照,差异幅度达57.8%;重度干旱胁迫时猪毛蒿L_(s)和WUE显著低于对照,糙隐子草F_(v)/F_(m)和F_(v)/F_(o)随降水减少而降低,中度以上的干旱胁迫时其值显著低于对照。(5)相关性分析表明,3个优势物种的P_(n)与F_(v)/F_(m)和F_(v)/F_(o)均呈显著正相关关系,其中猪毛蒿和糙隐子草的P_(n)—F_(v)/F_(m)和P_(n)—F_(v)/F_(o)斜率明显高于胡枝子。研究表明,气候变暖会在一定程度上加剧降水减少对沙质草地3种群落优势物种光合作用的抑制。     

小叶榕叶中具有抗HSV活性的黄烷成分(英文)

从小叶榕(Ficus microcarpa L.)叶的乙醇提取物中首次分离鉴定了(+)(2R,3S)阿夫儿茶素(1)、(-)(2R,3R)表阿夫儿茶素(2)、(-)(2R,3S)阿夫儿茶素-(4α-8)(2R,3S)阿夫儿茶素(3)、(-)(2R,3S)阿夫儿茶素-(4α-8)(2R,3R)表阿夫儿茶素(4)4个黄烷化合物,其中化合物1和2对兔肾细胞中培养的2型单纯疱疹病毒(HSV-2)具有抑制作用,半数抑制浓度(IC50)分别为0.49和0.55mgmL-1,治疗指数(TI)分别为4.31和3.19,可用作小叶榕叶药材质量控制的指标成分。从该提取物中还分离鉴定了另外7个已知成分:儿茶素(5)、phaseic acid(6)、苯甲酸(7)、4-羟基苯甲酸(8)、间苯三酚(9)、胡萝卜苷(10)和β-谷甾醇(11)。     

西南峡谷型喀斯特不同生态系统的碳格局

采用样方法研究了黔西南峡谷型喀斯特水田生态系统(ST)、旱地生态系统(HD)、草地生态系统(CD)、灌草生态系统(GC)、人工林生态系统(RGL)和次生林生态系统(CSL)的碳贮量、组成及其分布格局。结果表明:1)6种生态系统的植物碳贮量为RGL(121.53)CSL(116.76)GC(54.14)CD(36.05)ST=HD(0.00)103kg C/hm2,占植物碳贮量绝对贡献的层次:RGL和CSL为乔木层、GC为灌木层、CD为草本层;2)地被物碳贮量分别为CSL(18.34)﹥GC(5.82)﹥RGL(3.96)﹥CD(0.47)﹥ST=HD(0.00)103kg C/hm2,仅占生态系统总碳贮量的0%—4.9%;3)土壤碳含量为CSL(44.11)RGL(29.39)GC(21.50)CD(19.81)ST(17.56)HD(16.70)g C/kg,土壤碳贮量为CD(153.12)CSL(126.11)ST(112.26)HD(115.31)RGL(65.04)GC(52.69)103kg C/hm2,均随土壤深度的增加而显著降低,且与土壤深度之间有良好的线性关系;4)生态系统总碳贮量为CSL(261.21)﹥RGL(190.53)﹥CD(189.64)﹥HD(115.31)﹥GC(112.65)﹥ST(112.26)103kg C/hm2;RGL的碳格局为植物大于土壤,CSL反之,但都是地上大于地下;GC为植物约等于土壤,地下大于地上;ST、HD和CD为土壤大于植物,地下大于地上。黔西南峡谷型喀斯特固碳潜力很大,减少人为干扰、适宜的退耕还林还草造林措施和合理的管理对策是促进该区域植被恢复、生态重建、增加碳贮存的关键。     

非嗜食植物乙醇提取物对小菜蛾种群控制作用评价

通过建立实验种群生命表和自然种群生命表,应用种群趋势指数(indexofpopulationtrend,I)和干扰作用控制指数(interferenceindexofpopulationcontrol,IIPC),评价花椒(Zanthoxylumbungeanum)、细叶桉(Eucalyptustereticornis)、烟草(Nicotianatabacum)、构树(Broussonetiapapyrifera)、羊蹄甲(Bauhiniavariegata)、假莲翘(Durantarepens)、飞扬草(Euphorbiahirta)、茶枯(Camelliaoleifera)8种非嗜食植物乙醇提取物对小菜蛾实验种群的控制作用,以及细叶桉、烟草、茶枯3种非嗜食植物乙醇提取物及其混合液对小菜蛾自然种群的控制作用.室内试验结果表明,在各种植物乙醇提取物作用下,I值从小到大的顺序为4.4842(细叶桉)、5.3702(花椒)、5.5199(飞扬草)、6.1609(假莲翘)、6.8937(羊蹄甲)8.0945(烟草)、9.8052(茶枯)、11.1382(构树),对照的I值为69.8964;IIPC值从小到大的顺序为0.0642(细叶桉)、0.0768(花椒)、0.0790(飞扬草)、0.0881(假莲翘)、0.0986(羊蹄甲)、0.1158(烟草)、0.1403(茶枯)、0.1594(构树),说明供试植物提取物对小菜蛾实验种群增长都有一定的抑制和干扰作用.小菜蛾自然种群生命表研究结果表明,在各种植物乙醇提取物作用下,I值从小到大的顺序为5.1997(细叶桉)、7.4160(烟草)、7.3644(茶枯)和3.1399(混合液),对照的I值为21.6232;IIPC值从小到大的顺序为混合液(0.1608)、细叶桉(0.2405)、茶枯(0.3549)、烟草(0.3695),说明供试植物提取物都能明显降低种群趋势指数,在一定程度上抑制和干扰小菜蛾自然种群增长,在生产中有一定的应用前景.     

麻楝果实化学成分及其抗烟草青枯病菌活性的研究

为研究麻楝(Chukrasia tabularis)的化学成分,采用色谱法从麻楝果实乙醇提取物中分离得到15个化合物,利用波谱学方法鉴定其结构分别为:没食子酸甲酯(1)、没食子酸乙酯(2)、没食子酸(3)、ozoroalide(4)、stigmast-4-en-6β-ol-3-one(5)、黄柏呈(6)、chukranin A(7)、chisopanin M(8)、21α,24α-methylmelianodiol(9)、toonaciliatin K(10)、21α,25-dimethylmelianodiol(11)、odoratone(12)、bourjotinolone A(13)、hispidone(14)和phragmalin di-isobutyrate(15)。化合物4~14为首次从麻楝属植物中分离得到。采用滤纸片琼脂扩散法对单体化合物进行抗烟草青枯病菌(Ralstonia solanacearum)的活性研究,结果表明化合物1、2和3具有中等拮抗活性。     

RGNTF单抗与多抗的特性和抑制作用（简报）

We have immunized Balb/c mice and rabbits with a minute quantity of a 30 kD neuronotrophic factor which was isolated from the extract of newborn rat tectum (Te) by Phast System gel electrophoresis. Splenic cells from the immunized mice were hybridized with NS-1 mouse myeloma cells. Three clones were selected from 576 wells of hybridomas and were capable of secreting monoclonal antibodies specific to the retinal ganglion neuronotrophic factor (RGNTF-MAbs), namely A1, D3 and E8. Subtyping of the three monoclonal antibodies revealed that A1 and D3 are IgG3 and E8 is IgM. They maintained secreting antibodies even after six months of culturing in vitro. In order to determine the specificities of these antibodies, we have used their ascites fluids containing antibodies at a different dilutions to study their effects on the survival of retinal ganglion cells in vitro. The results indicated that at the dilution ranges of 1:250 to 2000, all three monoclonal antibodies exhibited inhibition on the survival of retinal ganglion cells and the inhibition increased with increases in antibody concentrations; especially at a dilution of 1:250, the E8 monoclonal antibody reaching 70% inhibition and A1 and D3 reaching 66% and 62% inhibition, respectively. Polyclonal antibodies from rabbits exhibited similar but weaker results of inhibition. We can conclude that the monoclonal and polyclonal antibodies can specifically inhibit the activity of the 30 kD retinal ganglion neuronotrophic factor.     

SARS-CoV单克隆抗体的制备及抗原表位的初步鉴定

参照已发表的SARS冠状病毒BJ01株基因序列 ,利用计算机软件预测并选取该病毒S、M、N三种主要结构蛋白部分抗原性优势区域 ,以编码Gly-Pro-Gly序列相连接合成两段嵌合基因A和B。并分别克隆于pGEX -6p- 1载体上用IPTG进行诱导表达 ,以纯化的嵌合蛋白A和B为抗原 ,分别免疫BALB c小鼠制备单克隆抗体。利用单克隆抗体亚型检测试剂盒和SARS CoV商品化ELISA检测试剂盒对其进行亚型和特异性鉴定。结果表明融合表达两段嵌合基因产物 ,其大小分别为 34kD和35kD ,Westernblot分析证实两种表达产物都能被SARS病人康复期血清所识别。获得了 6株能稳定分泌特异性抗体的阳性细胞克隆株。亚型鉴定结果除D3C5为IgG2a外其他单抗均为IgG1,而且所有单抗的轻链均为κ链。特异性鉴定发现除D3D1外 ,其余的 5株单抗均能与SARS CoV商品化ELISA检测试剂盒发生特异性反应。将D3D1与灭活后经超声波裂解的SARS CoV进行Westernblot分析 ,发现它能特异性识别 180kD的蛋白带。分别融合表达了 6个S蛋白的寡肽 (S1- S6 ) ,并对筛选出的单克隆…     

人凝血因子Ⅶ单克隆抗体的制备与鉴定

目的：制备抗人凝血因子Ⅶ单克隆抗体并鉴定其特性。方法：应用杂交瘤融合技术,以重组人凝血因子Ⅶ为抗原免疫BALB／c小鼠;取免疫小鼠的脾细胞与Sp2／0骨髓瘤细胞融合,经间接ELISA法筛选、融合细胞有限稀释法克隆、克隆化杂交瘤细胞株的亚类鉴定等方法筛选出单克隆抗体杂交瘤细胞株,并对单克隆抗体的特异性进行鉴定;用杂交瘤细胞株诱生小鼠腹水,应用蛋白A亲和层析法进行单抗的纯化。结果：获得了3株可稳定分泌单克隆抗体的杂交瘤细胞3E8、3D2和1C5,诱生的腹水效价分别为1：1×10^7、1：1×10^6和1：1×10^6;亚类鉴定表明388为IgG2a,其余2株均为IgGl;特异性鉴定显示它们与多种血浆蛋白均无交叉反应,表明单抗是特异的;经过亲和层析,获得了纯化的单抗。结论：获得了特异性的人凝血因子Ⅶ单克隆抗体,为建立人凝血因子Ⅶ检测及纯化方法奠定了基础。     

Monoclonal antibody for calcitriol (1 alpha,25-dihydroxyvitamin D3)

Hybridoma cell lines secreting antibodies for vitamin D3 metabolites have been generated by fusing splenocytes from BALB/c mice immunized with 3 beta-glutaryl-25-hydroxyvitamin D3 conjugated to bovine serum albumin (3 beta-glu-25-OH-D3-BSA) and Sp2/O-Ag14 myeloma cells. Purification of monoclonal antibodies from culture media or ascites fluids was accomplished by procedures including affinity chromatography on Protein A-Sepharose 4B. Each monoclonal antibody was analyzed as to its affinity and specificity by equilibrium dialysis and an enzyme immunoassay (EIA) based on a double antibody system. It was demonstrated that clone 1C2-60 produced an antibody highly specific to 1 alpha,25-dihydroxyvitamin D3 (calcitriol), and the clone 2B3-66 antibody was reactive to 25-hydroxyvitamin D3 and similar structural compounds. These two monoclonal antibodies produced by 1C2-60 and 2B3-66 were determined to belong to the IgG2a class, and their affinity constants (Ka) with 3 beta-glu-25-OH-D3 were demonstrated to be 3.6 X 10(9) M-1 and 2.9 X 10(9) M-1, respectively, at 4 degrees C. The characteristics of these monoclonal antibodies were compared with those of conventional antibodies raised in mice and rabbits. Finally, by using monoclonal antibody 1C2-60, a sensitive EIA has been developed that can detect 10 pg of calcitriol.     

大麦黄花叶病毒单克隆抗体的制备

大麦黄花叶病毒(Barley yellow mosaic virus,BaYMV)广泛分布于西欧、日本和我国长江中下游和东部沿海地区,严重危害了大麦生产,并呈现出不断蔓延扩大的趋势。该病毒经土壤禾谷多粘菌介体感染大麦后,病毒繁殖发病的状况,易受到大麦品种不同、环境温湿度等因素的影响,发病程度的差异很大,而且还发现带毒隐症的大麦品种,使大麦抗源筛选和大麦抗性品种的选育工作受到严重干扰,因此迫切需要建立一种快速、灵敏和准确的检测方法。目前,比较理想的方法是ELISA等免疫学技术。     

Detection of multiple antigenically related proteins from various rat tissues by monoclonal antibodies against 3 alpha-hydroxysteroid dehydrogenase.

Mouse hybridomas were prepared by fusing myelomas and spleen cells from mice immunized with purified rat 3 alpha-hydroxysteroid dehydrogenase. Hybridomas secreting monoclonal antibodies against 3 alpha-hydroxysteroid dehydrogenase were selected by indirect enzyme-linked immunoassay and then subcloned by limiting dilution. From two mice we have obtained four positive hybridomas, three secreting high affinity immunoglobulin (Ig) G1 and one secreting IgM. Only two of these monoclonal antibodies (MAbs 3G6 and 7D3, both IgG1) recognized denatured enzyme and, therefore, were used for further immunoblotting experiments. MAb 7D3 recognized a structurally related mouse enzyme, but not the human enzyme, whereas monoclonal antibody 3G6 recognized a human enzyme, but not the mouse enzyme. When these two monoclonal antibodies were used in immunoblotting to survey the expression of 3 alpha-hydroxysteroid dehydrogenase in rat liver and a number of other tissues, striking differences were found in the protein band patterns in kidney, lung, and testis. Both MAbs 7D3 and 3G6 recognized 3 alpha-hydroxysteroid dehydrogenase, a 34-kDa 7D3 recognized a protein of the same size as the liver protein, whereas MAb 3G6 recognized a 34-kDa protein plus another protein of 36 kDa. In kidney only MAb 3G6, but not MAb 7D3, recognized a 34-kDa protein. Conversely, the 34-kDa protein in testis was recognized by MAb 7D3, but not by MAb 3G6. These findings suggest the existence of multiple antigenically related proteins in different tissues.     

异色瓢虫卵黄蛋白单克隆抗体的制备及鉴定

【目的】为了能准确地追踪异色瓢虫Harmonia axyridis (Pallas)卵黄原蛋白（vitellogenin, Vg）的合成、转运途径和吸收方式,以及卵黄蛋白（vitellin, Vn）在卵母细胞内的积累及分布情况,本研究对异色瓢虫的Vn进行了单克隆抗体（monoclonal antibody, McAb）的制备。【方法】以异色瓢虫Vn免疫BLAB/C小鼠,应用杂交瘤技术,经过3次亚克隆筛选,制备能稳定分泌抗Vn的单克隆抗体。【结果】实验获得4株能够稳定分泌抗异色瓢虫Vn的单克隆抗体,即5E2, 5E11, 1E9和5H8。其中1E9, 5E11和5E2亚型均为IgG1,5H8亚型为IgM。Western blot免疫印迹分析显示,4株单克隆抗体可以特异性地识别Vn,而与雄虫血淋巴无反应。其中,5E2和1E9可以与异色瓢虫抗原的4个亚基发生较强的免疫反应,结合腹水制备前上清效价检测结果最终选取5E2制备单克隆抗体。5E2单克隆抗体的效价为1∶81 000,SDS-PAGE分析显示5E2重链和轻链的分子量分别为50和27 kD。【结论】本实验成功制备出一株能够稳定分泌抗异色瓢虫Vn的单克隆抗体,为建立酶联免疫吸附试验（ELISA）方法测定其动态变化奠定了基础。     

Asia I口蹄疫vp2蛋白单克隆抗体的制备及单抗竞争ELISA方法的建立

制备Asia I口蹄疫病毒vp2单克隆抗体(mAb)并建立了单抗竞争ELISA方法。用纯化的Asia I型口蹄疫病毒vp2重组蛋白免疫BALB/c小鼠, 将免疫小鼠的脾细胞与骨髓瘤SP2/0细胞融合, 采用间接ELISA和有限稀释法筛选杂交瘤细胞。分别用ELISA、Western blotting检测mAb腹水的效价及其特异性。筛选到杂交瘤细胞2株, 腹水效价均在100×29以上; 以纯化后的Asia I型口蹄疫病毒vp2重组蛋白作为抗原, 利用Asia I型口蹄疫病毒vp2单抗酶标物建立了竞争ELISA方法用来检测Asia I型口蹄疫抗体。临床应用表明, 该方法与UBI公司的口蹄疫全病毒抗体检测试剂盒总符合率达89.0%, 和荷兰赛迪公司的口蹄疫病毒LPB-ELISA抗体检测试剂盒总符合率达86.5%。     

Production of Monoclonal Antibodies to Guinea Pig Liver Transglutaminase

Monoclonal antibodies are now a powerful tool in biology and medicine. Transglutaminase has been implicated in diverse biological functions, and the characteristics of its catalytic action are suitable for applied enzymology. In this study, we produced hybridoma cells which synthesize monoclonal antibodies against guinea pig liver transglutaminase by fusing mouse myeloma cells with spleen cells of mouse immunized with the enzyme protein. Eight hybridoma clones (coded 2F, 4B, 7C, 8B, 8D, 8E, 9F and 11C) were selected to produce monoclonal antibodies. The subclass of IgG produced by clone 9F was IgG_2a and those from the seven other clones were all IgG₁ The 9F antibody inhibited transglutaminase activity, but the other antibodies did not. A solid-phase antibody-binding assay showed that of these antibodies, 8D antibody has the highest affinity to the antigen. Transglutaminase protein in crude liver extract was identified with Western blotting analysis using 8D antibody as the probe.     

Analysis of ephrin-A2 in the chick retinotectal projection using a function-blocking monoclonal antibody

Eph receptor tyrosine kinases and their ligands have been shown to be involved in processes of cell migration and axon guidance during embryonic development. Here we describe the development of a function-blocking monoclonal antibody against chick ephrin-A2, and its effect on retinal ganglion cell axons studied both in vitro and in vivo. In the stripe assay, the blocking antibody completely abolished the repulsive effect of posterior tectal membranes. In vivo, in a loss-of-function approach, hybridoma cells secreting the antiephrin-A2 antibody were applied to chick embryos from embryonic day 3 (E3) on, and the retinotectal projection was subsequently analyzed at E16. DiI tracing analyses showed that although the projection of both temporal and nasal retinal ganglion axons in the tectum was, overall, normal, occasionally diffuse and extra termination zones were observed, in addition to axons over-shooting their termination zones. These data support the idea that ephrin-A2 contributes to the establishment of the chick retinotectal projection.