花椰菜与黑芥种间体细胞杂种的获得和鉴定

利用非对称体细胞杂交技术, 获得芸薹属花椰菜(Brassica oleracea var. botrytis)与黑芥(B. nigra)的种间杂种, 实现了野生种质抗病基因向甘蓝类蔬菜作物的渗透。以具有良好再生能力的花椰菜下胚轴原生质体作为融合受体, 具有抗黑腐、黑胫和根肿病优良性状的黑芥叶肉原生质体作为融合供体, 用不同强度的UV射线处理后, 利用PEG方法诱导供、受体原生质体融合。培养后获得170棵再生植株, 选取来自40个不同愈伤组织的40棵单株进行形态学观察及RAPD和SRAP分子标记检测, 结果表明其中30棵为体细胞杂种。染色体计数显示, 约23%杂种植株的染色体数目小于供、受体染色体数之和。用流式细胞仪测定DNA含量显示, 杂种植株DNA含量是受体的2-4倍, 20%杂种植株DNA含量小于供、受体之和。     

花椰菜与黑芥非对称体细胞杂种的鉴定分析

选用兼具抗黑腐病、黑胫病、根肿病的野生种质黑芥(B.nigra)作为供体,具有良好原生质体培养能力的花椰菜(Boleracea var.botrytis L.)基因型"0307"作为受体,供体叶肉原生质体经不同剂量UV照射处理后,通过PEG介导,与不经任何处理的受体下胚轴原生质体融合,培养获得再生植株.形态学观察显示再生植株的表型多样,呈偏向受体花椰菜类型及中间类型分布:SRAP分子标记特征表明,杂种中受体的遗传信息较为完整,而来自供体的特异扩增带丢失量约为20.0%-97.8%,且不同杂种中存在热点丢失序列;约23.0%的再生植株其染色体数目小于供、受体染色体数之和;采用流式细胞仪对再生株的细胞DNA含量进行分析,结果显示,20%的植株其DNA含量小于供、受体DNA含量总和.对22棵再生植株进行了黑腐病人工接种抗性鉴定,17棵再生植株表现良好抗性,初步证明通过非对称体细胞杂交技术已将外源抗性基因转入花椰菜中.实验表明UV辐射处理,导致再生植株中供体遗传信息的部分丢失或者染色体在不同程度上的消减,获得了花椰菜与黑芥的非对称体细胞杂种,但UV的剂量效应不明显.     

甘薯同一不亲和群内品种间体细胞杂种

利用PEG融合方法,融合甘薯(Ipomoea batatas)B不亲和群内品种‘koganesengan'和‘bitambi'的原生质体.将融合处理的原生质体进行培养,共获得45株再生植株.4株再生植株形态上表现出融合双亲的中间特性,其中2株染色体数为融合两亲之和(2n=12x(2n 2n)=180),另外2株分别为41～103和35～100,因细胞不同而不同.经RAPD分析,这4株再生植株分别具有双亲特异的DNA扩增带或双亲都不具有的新扩增带.鉴定这4株再生植株为杂交不亲和的B群内品种间体细胞杂种.     

电融合获得用于选择抗CTV砧木的酸橙与甜橙体细胞杂种植株

在已知参数条件下,通过电场诱导酸橙(Citrus aurantium L.)叶肉原生质体和沙漠蒂甜橙(C.sinensis Osbeck cv.Shamouti)的胚性愈伤组织原生质体融合,融合产物经培养再生出40棵植株.染色体检查表明所得到的植株具有36条染色体,为四倍体植株.再生植株具有翼叶,叶片厚,表现出多倍体的特征.采用2个10-碱基随机引物鉴别再生植株的杂种特性.在2个引物的扩增带型中,再生植株的随机扩增带图里出现了融合亲本的特征带.对再生植株染色体计数和RAPD分析的结果表明它们是酸橙和甜橙种间异源四倍体体细胞杂种植株.这些体细胞杂种植株的获得为选择具有酸橙优良性状、同时抗CTV的新型砧木提供了好的试材.     

电融合获得用于选择抗CTV砧木的酸橙与甜橙体细胞杂种植株

在已知参数条件下,通过电场诱导酸橙（Cit-rus aurantium L.）叶肉原生质体和沙漠蒂甜橙（C.sinensis Osbeck cv.Shamouti）的胚性愈伤组织原生质体融合,副合产物经培养再生出40棵植株。染色体检查表明所得到的植株具有36条染色体。为四倍体植株。再生植株具有翼叶,叶片厚,表现出多倍体的特征,采用2个10－碱基随机引物鉴别再生植株的杂种特性。在2个引物的扩增带型中,再生植株的随机扩增带图里出现了融合亲本的特征带。对再生植株染色体计数和RAPD分析的结果表明它们是酸橙和甜橙种间异源四倍体体细胞杂种植株。这些体细胞杂种植株的获得为选择具有酸橙优良性状、同时抗CTV的新型砧木提供了好的试材。     

同一小麦品种不同来源的两种原生质与簇毛麦原生质体融合再生杂种植株

小麦（Triticum asetivum L.)济南177的两种原生质体,一种来自快速生长的悬浮细胞,它们因长期继代而丧失分化能力,其染色体只有2n-24-28,另一种来自可以再生的愈伤组织,其原生质体不能持续分裂,它们中任一种与UV照射过的簇毛麦原生质体融合均不能再生植株,然而当它们混合在一起作为受体时,能够获得再生绿色植株,细胞核基因和胞质基因的分析证明这些绿色植株是杂种,以上事实说明这两种原生质体在融合时存在某些互补的关系,讨论了这种融合方式的可能作用及重要性。     

脐橙与柠檬种间细胞电融合再生杂种植株

‘纽荷尔’脐橙（Ｃｉｔｒｕｓｓｉｎｅｎｓｉｓ（Ｌ．）Ｏｓｂｅｃｋ）胚性细胞悬浮原生质体与‘尤力克’柠檬（Ｃｉｔｒｕｓｌｉｍｏｎ（Ｌ．）Ｂｕｒｍ．ｆ）叶肉原生质体经电场诱导融合,培养８个月,首批再生了１棵植株,形态学观察,染色体计数及ＲＡＰＤ分析证明异源四倍体体细胞杂种,该杂种的获得为三倍体无籽柠檬品种培育提供了杂交亲本。     

白菜与甘蓝之间体细胞杂交种获得与遗传特性鉴定

为拓宽白菜育种的基因资源,改良白菜品质,以白菜(Brassica campestris,2n=20,AA)和甘蓝(B.oleracea L.var.capitata,2n=18,CC)的子叶和下胚轴为材料分离、制备原生质体。采用40%聚乙二醇(Polyethylene glycol,PEG)进行原生质体融合。融合细胞在以0.3 mol/L蔗糖、0.3 mol/L葡萄糖为渗透稳定剂,附加1.0 mg/L 2,4-D+0.5 mg/L 6-苄氨基嘌呤(6-BA)+0.1 mg/L 1-萘乙酸(NAA)+1.0 mg/L激动素(Kinetin,Kin)的改良K8p培养基中培养并诱导细胞分裂。小愈伤组织经增殖培养后在MS+0.2 mg/L玉米素(Zeatin,ZEA)+1 mg/L 6-BA+0.5 mg/L Kin+0.4 mg/L NAA的固体分化培养基上诱导出不定芽。30 d后再转入MS基本培养基,获得完整的再生植株。将生根的植株转移到花盆,并对其杂种性质进行形态学、细胞学和分子生物学鉴定。结果表明,经细胞融合分裂出的320个愈伤组织中,获得了35棵再生植株,其再生率达10.94%。形态学观察显示,绝大多数再生植株的叶面积较大,株型和叶型为两种杂交亲本的中间型,部分植株的叶片浓绿、肥厚。染色体计数结果显示,36.4%的再生植株染色体数为2n=38;36.4%的再生植株的染色体数为2n=58 60;27.2%的再生植株的染色体数为2n=70 76,超过两个融合亲本的染色体数的总和。流式细胞仪测定DNA含量显示,再生植株DNA含量变化比较大,其结果与染色体鉴定结果相吻合。随机扩增多态性DNA(Randomamplified polymorphic DNA,RAPD)和基因组原位杂交(Genomic in situ hybridization,GISH)分析结果证明再生植株具有双亲基因组。体细胞杂种花粉育性比较低,杂交、回交后其育性逐渐获得恢复,与白菜回交后代逐渐恢复了育性。通过体细胞杂交和回交、杂交获得了形态变化广泛的个体,为白菜的品种育种提供多样的种质资源。     

青花菜与白菜间体细胞杂种获得与遗传特性鉴定

为获得芸薹属白菜Brassica campestris与青花菜Brassica oleracea var. botrytis的种间体细胞杂交体,以青花菜和白菜的子叶与下胚轴为材料,分离制备原生质体,用40％聚乙二醇 (Polyethylene glycol,PEG) 进行原生质体融合。融合细胞在以0.3 mol/L 蔗糖、0.3 mol/L葡萄糖为渗透稳定剂,附加0.2 mg/L 2,4-D+0.5 mg/L 6-苄氨基嘌呤 (6-BA) +0.1 mg/L 1-萘乙酸 (NAA) +0.1 mg/L激动素 (Kinetin,Kin) 的改良K8p培养基中液体浅层培养。将包埋于0.1％琼脂糖的8~10个细胞期的细胞在添加0.3 mol/L蔗糖和2 mg/L 6-BA+2 mg/L玉米素 (Zeatin,ZEA) +1 mg/L NAA+0.5 mg/L Kin的Kao培养基中诱导愈伤组织。愈伤组织转到MS+5 mg/L ZEA+2 mg/L IAA诱导不定芽。将长1～2 cm的不定芽转到1/2 MS+0.2 mg/L NAA诱导生根。将生根的植株转移到花盆,并对其杂种性质进行形态学、细胞学和分子生物学鉴定。结果表明,融合细胞培养2～7 d后发生第1次分裂,培养35 d后植板率为0.66％,不定芽再生率达3.7％。形态学观察显示,绝大多数再生植株的叶面积较大,株型和叶型为两种杂交亲本的中间型。染色体计数结果显示,再生植株染色体数目为2n=38。流式细胞仪测定DNA含量显示,再生植株DNA含量是亲本之和。随机扩增多态性DNA (Random amplified polymorphic DNA,RAPD) 和基因组原位杂交 (Genomic in situ hybridization,GISH) 分析结果证明再生植株具有双亲基因组。体细胞杂种花粉育性比较低,杂交、回交后其育性逐渐获得恢复。     

甘薯同一不亲和群内品种间体细胞杂种

利用PEG融合方法,融合甘薯(Ipomoea batatas ) B不亲和群内品种‘koganesengan’和‘bitambi’的原生质体。将融合处理的原生质体进行培养,共获得45株再生植株。4株再生植株形态上表现出融合双亲的中间特性,其中2株染色体数为融合两亲之和（2n = 12x (2n + 2n) = 180）,另外2株分别为41～103和35～100,因细胞不同而不同。经RAPD分析,这4株再生植株分别具有双亲特异的DNA扩增带或双亲都不具有的新扩增带。鉴定这4株再生植株为杂交不亲和的B群内品种间体细胞杂种。     

Embryo and Endosperm Function and Failure inSolanumSpecies and Hybrids

Although the importance of the endosperm as a food store inmany angiosperm seeds is well known, its significance duringearly embryogenesis has been neglected. In many interspecifichybrids, and in some other situations, embryos do not developfully and abort. It has often been stated that this is causedby the endosperm failing to conduct sufficient nutrients tothe embryo, but seldom has it been suggested that the endospermactively controls most of the early stages of morphogenesisof the embryo. Information gleaned from a broad survey of theliterature, combined with additional evidence presented here,obtained fromSolanum incanumand interspecific hybrids, indicatethat the endosperm is dynamic and very active in regulatingearly embryo development. This requires highly integrated geneticcontrol of rapidly changing metabolism in the endosperm. Ininterspecific hybrids, lack of coordination may cause unbalancedproduction of growth regulating substances by the endospermand hence abortion of the embryo, or even unregulated productionof nucleases and proteases resulting firstly in autolysis ofthe endosperm and then digestion of the embryo. The endospermmay thus serve to detect inappropriate hybridization of speciesor ploidy levels and so prevent waste of resources by producingseeds that would result in sterile hybrids or unthrifty subsequentgenerations. This discriminatory function of the endosperm hasdiminished during evolution and domestication of the crop plantSolanummelongenaL.Copyright 1998 Annals of Botany Company Solanum, embryo morphogenesis, endosperm, hybrid, seed development.     

HIFs and tumors--causes and consequences

For most organisms oxygen is essential fo life. When oxygen levels drop below those required to maintain the minimum physiological oxygen requirement of an organism or tissue it is termed hypoxia. To counter act possible deleterious effects of such a state, an immediate molecular response is initiated causing adaptation responses aimed at cell survival. This response is mediated by the hypoxia-inducible factor-1 (HIF-1), which is a heterodimer consisting of an alpha- and a beta-subunit. HIF-1 alpha protein is stabilized under hypoxic conditions and therefore confers selectivity to this response. Hypoxia is characteristic of tumors, mainly because of impaired blood supply resulting from abnormal growth. Over the past few years enormous progress has been made in the attempt to understand how the activation of the physiological response to hypoxia influences neoplastic growth. In this review some aspects of HIF-1 pathway activation in tumors and the consequences for pathophysiology and treatment of neoplasia are discussed.     

环腺苷酸应答元件结合蛋白与学习记忆

环腺苷酸(cAMP)应答元件结合蛋白(cAMP response element binding protein,CREB)是一种核转录因子,可与cAMP反应元件结合,调节基因转录,具有调节精子生成,昼夜节律,学习记忆等功能.近年来关于其在学习记忆中的作用成为医学研究热点.CREB是神经元内多条信息传递途径的汇聚点,参与长时记忆形成和突触可塑性.长时记忆(long-term memory)形成需依赖CREB介导的基因转录,干扰或抑制CREB活性可破坏长时记忆.长时程增强(long-term potentiation,LTP)是研究学习记忆的理想模型,在LTP诱导和维持过程中均可观察到CREB活性持续升高.但增龄过程中,海马CREB活性下降,影响学习记忆功能,与许多神经退行性疾病发生有关.     

Astrocytes and Synaptosomes Transport and Metabolize Lactate and Acetate Differently

Astrocytes transport the monocarboxylate acetate, but synaptosomes do not. The reason for this is unknown, because both preparations express monocarboxylate transporters (MCT). The transport and metabolism of lactate, another monocarboxylate, was examined in these two preparations, and the results were compared to those for acetate. Lactate transport is more rapid in astrocytes than in synaptosomes, but of lower affinity (Kms of 17 and 4 mM, respectively). Lactate (0.2 mM) is metabolized to CO2 more rapidly in synaptosomes than in astrocytes (rates of 0.37 and 0.07 nmol x mg protein(-1) x min(-1), respectively). The reason for this is unclear, but cellular differences in lactate dehydrogenase isotype expression may be involved. Acetate is metabolized to CO2 more rapidly in astrocytes than in synaptosomes (rates of 0.43 and 0.02 nmol x mg protein(-1) x min(-1), respectively). This is likely due to cellular differences in the expression of monocarboxylate transporter subtypes.