Two LINE 1 repeats in rat

One LINE 1 repeat has been located 661 bp downstream from the last albumin exon and another approx. 10 kbp downstream from the last alpha-fetoprotein exon in the rat genomic DNA. The LINE 1 repeat following the albumin gene is truncated at its 5' end and is 1204 nucleotides long. The 5' end of the longer repeat downstream from the alpha-fetoprotein gene has not been determined. The two repeats have 95% homology with each other, with the exception of a short diverse 3' end sequence just preceding the putative polyadenylation signal.     

小麦间期集缩染色质的超微结构研究

本文以普通小麦(Triticum aestivum L.)根端分生组织为材料,在透射电镜下对间期细胞核内的集缩染色质的高层次结构进行了研究。在其中观察到直径约为20—25nm、50nm及110—120nm 的不同等级染色线,并且发现直径110—120nm 的染色线是由50nm 的染色线组成的,而直径约50nm 的染色线是由20—25nm 的染色线组成的。对这三个层次染色质结构之间的集缩方式进行了讨论。     

植物单盐毒害和离子拮抗机理研究Ⅰ.单盐和混合盐对植物原生质体膜某些特性、超氧物歧化酶和过氧化氢酶活性的影响

单盐(KCl, CaCl_2或MgCl_2)和混合盐(KC_1+CaCl_2或KCl+MgCl_2)对植物原生质体完整率、存活率和膜透性等均有明显影响。K~+、Ca~(2+)或Mg~(2+)等单种阳离子明显降低原生质体膜完整率和存活率而增加其物质渗漏量,其中以单价阳离子K~+的影响为甚。上述单种阳离子还明显降低小麦幼叶超氧物歧化酶(SOD)和过氧化氢酶活性。只有由单价和二价阳离子组成的平衡混合盐才能使原生质体维持较高的完整率、存活率和较正常的膜透性.并能使细胞维持较高的SOD和过氧化氢酶活性。 认为单盐毒害机理可能是首先引起细胞膜发生不正常的膜相变或细胞累积较多的有害氧自由基,引起膜脂发生过氧化或脱酯化而破坏膜结构。在离子平衡混合盐作用下,膜系才能维持正常液晶相,具有较高活性的SOD和过氧化氢酶等生物保护性酶系是离子拮抗作用之原因。     

桂西壮族手皮纹的分析

本文对广西西部500例健康壮族大、中学生的手皮纹进行了观察分析,计算出各型指纹频率、指纹脊线总数、指纹频度指数、atd角度、a-b脊线数、τ距比、主线横向指数、皮纹花样出现率、掌褶纹出现率共九项基本参数,并将这些数值与汉族作了比较,桂西壮族的手纹与汉族既有相似之处,又有本民族的特点。     

Production and characterization of a monoclonal antibody cross-reactive with most group A trichothecenes

A monoclonal antibody cross-reactive with most group A trichothecenes was produced by fusion of P3/NS-1/1-AG4-1 myeloma cells with spleen cells isolated from a BALB/c mouse that had been immunized with 3-acetyl-neosolaniol-hemisuccinate conjugated to bovine serum albumin. One stable clone, H159B1D5, which produced monoclonal antibody that bound with both T-2 toxin and diacetoxyscirpenol (DAS) was obtained after subcloning. Enzyme-linked immunosorbent assay (ELISA) revealed that the antibody belongs to the immunoglobulin G1 (kappa chain) isotype and had binding constants of 2.81 x 10(9), 1.05 x 10(9), and 1.57 x 10(8) liters per mole for T-2 tetraol tetraacetate, T-2 toxin, and DAS, respectively. The relative cross-reactivities of the antibody with T-2 tetraol tetraacetate, T-2 toxin, and DAS were 200, 100, and 20, respectively, with tritiated T-2 toxin as the marker ligand. The relative cross-reactivities for the above toxins were 667, 100, and 73, respectively, with tritiated DAS as the marker ligand. No cross-reaction with HT-2 and deoxynivalenol triacetate was observed in either system. By using this monoclonal antibody, an indirect ELISA for analysis of T-2 toxin was also developed. The linear portion of the standard curve for analysis of T-2 toxin in each analysis by radioimmunoassay and ELISA was in the range of 0.1 to 2 ng and 0.05 to 1.0 ng, respectively.     

Effects of traces of rare earth elements on the protozoanBlepherisma and on mice

The growth of the protozoanBlepherisma is stimulated by Lanthanum (La) at concentrations as low as 0.32 ppm. In mice Yttrium (Y) and Ytterbium (Yb) are absorbed, accumulated, and metabolized. Both rare earth elements (RE) exhibit a high affinity for teeth and bones, accumulation occurs and metabolism is slow. In the livers of RE-exposed mice, concentrations are variable. The liver is apparently capable of absorbing and discharging RE in a manner depending on metabolic activity. The main route of discharge for ingested REs is the alimentary canal. Exposure of pregnant mice to RE leads to rapid placental transfer of RE; 14.1% of the total amount of RE administered was detected in newborn mice. Young, developing organisms appear to be especially susceptible to RE accumulation.     

Cross-reactivity of antibodies against T-2 with deepoxide T-2 toxin

Two types of antibodies raised against T-2 toxin, namely anti-T-2-HS-BSA and anti-3 -Ac -NEOS-HS -BSA, showed good cross-reactivity with deepoxy T-2 toxin. Our results indicate that the epoxide is not an important epitope for the production of antibody against T-2 toxin     

Tubulin isotypes and their interaction with microtubule associated proteins

Summary To assay the functional significance of the multiple but closely related - and -tubulin polypeptides (termed isotypes) that are expressed in mammalian cells, we have generated a number of sera that uniquely discriminate among these isotypes. These sera have been used to demonstrate that there is no subcellular sorting of either - or -tubulin isotypes among microtubules of diverse function, either in cells growing in culture or in tissues consisting of cell types that contain specialized kinds of microtubule. In spite of this failure to segregate between functionally distinct kinds of microtubule, the fact that isotype-specific amino acid sequences have been strictly conserved over extensive periods of evolutionary time argues persuasively for a functional role for the different tubulin gene products. One possibility is that they are required for specific interactions with microtubule associated proteins (MAPs), and that tubulin isotypes have coevolved with different cell type-specific MAPs with which they must interact. We have tested this hypothesis by examining the distribution of -tubulin isotypes in mammalian cerebellum in relationship to the known patterns of expression of a number of MAPs, and find that these patterns correlate in the case of M 2 and MAP 3, and M 6 and MAP 1 a. These data, plus emerging data based on a structural analysis of tau, MAP 1 b and MAP 2 obtained via sequence determination of cloned cDNAs, are discussed in terms of the possible functional significance of tubulin isotype/MAP interactionsin vivo.     

小麂、黑麂、赤麂精母细胞联会复合体的比较研究

本工作以界面铺张——硝酸银染色技术,对小麂(Muntiacus reeuesi)、黑麂(M.crinifrons)和赤麂(M.muntjak)的精母细胞联会复合体(Syna ptonemal complex,SC)进行亚显微结构的比较研究。结果表明: 1.SC的平均相对长度和臂比指数同有丝分裂细胞相应染色体的数值有很好的一致性。根据SC的相对长度和臂比指数绘制了三种麂的SC组型图。雄性黑麂减数分裂前期形成一个复杂的易位多价体,意味着其核型的演化过程涉及两次染色体易位和一次臂间倒位。 2.在减数分裂前期,性染色体的形态和行为同常染色体的有明显差异,如性染色体嗜银性较强,配对延迟等。XY的配对起始于早粗线期,在中粗线期,Y的全长均同X配对;XY-SC开始解体于晚粗线期。 3.在粗线期,X染色体未配对区域出现自身折叠,形成“发夹”状结构。这种“发夹”结构的形成,可能是在性染色体的进化过程中,X染色体通过不对称易位得到的重复片段在减数分裂前期同源配对的一种细胞学表现。