人类睾丸精子和附睾精子的顶体蛋白酶活性

精子形成过程最明显的条件之一是顶体的发育，顶体蛋白酶则是顶体内发育的重要酶类。人类射出精子的顶体蛋白酶活性已有研究，但在人睾丸和附睾水平，顶体蛋白酶的活性状态国内外尚无报道。本文探讨顶体蛋白酶在人睾丸和附睾部位的活性和变化。先天性双侧输精管缺如者取睾丸精子和附睾精子；精索静脉曲张结扎者取睾丸精子和射出精子。睾丸精子从常规睾丸活检组织中分离；附睾精子在阴囊探查术或人工贮精囊术时获取。射出精子为手淫法取精。应用明胶薄层试验、去透明带地鼠卵穿透试验和透射电镜观察顶体蛋白酶活性及其影响。实验结果表明，睾…     

冷冻保存对人类精子顶体蛋白酶的影响

探讨了冷冻保存对人类精子顶体蛋白酶的影响,应用明胶薄层法检测,冷冻保存后精子顶体蛋白酶反应率和成环直径显著减少（ｎ＝３０,Ｐ＜０．０１）．透射电镜观察到冷冻保存后精子（ｎ＝３）头部结构完整性显著降低,提示浆膜、顶体膜超微结构的冷冻损伤与冷冻精子顶体蛋白酶活性丢失和降低有关．冷冻精子穿卵率与顶体蛋白酶反应率不呈相关性（ｎ＝２１,ｒ＝０．３４,Ｐ＞０．０５）,提示两项检测反映的是精子功能的不同方面．     

驴精子顶体蛋白酶的提纯及其一些性质的研究

顶体蛋白酶acrosin(EC3、4、21、10)是存在于哺乳动物精子顶体中的一种丝氨酸蛋白酶,生化性质上属于水溶性碱性糖蛋白,专一水解精氨酰键,最适pH为8.0—8.5。首先在兔精子中提取了顶体蛋白酶,发现此酶能分解兔卵透明带,并且被胰蛋白酶抑制剂所抑     

赤小豆胰蛋白酶抑制剂对人体精子体外抑制作用及其作用机理的初步探讨

本文首次报道,用从中药赤小豆(Phaseolus calcaratus Roxb)中提纯的胰蛋白酶抑制剂,剂量在400μg/0.2ml以上,在体外能全部抑制人体精子。该抑制剂对人体精子顶体粒蛋白亦有较强的抑制作用,初步探讨了它对人体精子顶体粒蛋白的抑制作用机理。通过进一步研究,赤小豆抑制荆可望成为一种新型的避孕药。     

赤小豆胰蛋白酶抑制剂抑制人体精子顶体蛋白酶的动力学

通过一系列酶促反应动力学的研究，结果表明赤小豆胰蛋白酶抑制剂对人体精子顶体蛋白酶（Ａｃｒｏｓｉｎ）有较强的不可逆竞争性抑制作用．其Ｋｍ和Ｋｉ值分别为１．８６×１０－３ｍｏｌ／Ｌ和２．１×１０－５ｍｏｌ／Ｌ．     

赤小豆胰蛋白酶抑制剂的分离纯化及其性质研究

用酸抽提、2.5％TCA热处理、硫酸铵盐析、凝胶层析和DEAE纤维素离子交换层析等方法,从中药赤小豆中分离得到一种胰蛋白酶抑制剂。聚丙烯酰胺凝胶电泳呈单一谱带。经SDS-聚丙烯酰胺凝胶电泳法测定,其分子量为7400。N-末端分析和氨基酸组成测定结果表明,赤小豆胰蛋白酶抑制剂不含半胱氨酸和胱氨酸,是以酪氨酸为N-末端,由54个氨基酸残基组成的单一多肽链。它仅对胰蛋白酶有较强的抑制作用,对胰凝乳蛋白酶、枯草杆菌蛋白酶和木瓜蛋白酶均无明显的抑制活力,对热及酸碱亦较稳定。     

中华绒螯蟹(Eriocheir sinensis)精子的形态和顶体反应的研究

研究了利用离子载体A23187诱导中华绒螯蟹（Eriocheir sinensis）精子产生顶体反应的最佳条件．结果表明：从雌性中华绒螫蟹纳精囊中获得的精子，在pH值为6．0，CaCl2浓度为0．2％的人工海水中，用离子载体A23187（40μg／mL）诱导70min，可以得到最大的精子顶体反应率（72％）．在此基础上用光镜观察了顶体反应过程中精子显微结构的变化，并采用天然海水配制的台盼蓝染色液和曙红B染色液对中华绒螯蟹精子的形态进行观察，确定中华绒螫蟹精子的顶体反应过程大致可分为4个阶段：第一阶段为辐射臂收缩，头帽鼓起；第二阶段为顶体囊外翻；第三阶段为顶体管前伸；第四阶段为顶体丝形成．     

锈斑(虫寻)(Charybdis feriatus)精子超微结构的研究

利用透射电镜研究了锈斑虫寻成熟精子的超微结构,结果表明这类精子呈不规则的扁球形,无鞭毛,精子由球形的顶体、核杯及辐射臂组成。顶体结构复杂,包括头帽、顶体管与顶体囊,顶体囊包绕在顶体管的中央管周围。顶体被杯状的核包裹,仅头帽露于精子表面。中心粒、线粒体及少量的其它细胞器出现在核杯中。精子的表面有由核外突形成的辐射臂约2条。     

锈斑蝇（Charybdis feriatus）精子超微结构的研究

利用透射电镜研究了锈斑蟳成熟精子的超微结构，结果表明这类精子呈不规则的扁球形，无鞭毛，精子由球形的顶体、核杯及辐射臂组成、顶体结构复杂，包括头帽、顶体管与顶体囊，顶体囊包绕在顶体管的中央管周围。顶体被杯状的核包裹，仅头帽露于精子表面。中心粒、线粒体及少量的其它细胞器出现在核杯中。精子的表面有由核外突形成的辐射臂约2条。     

人输卵管液和输卵管上皮细胞培养液诱发精子的顶体反应

目的：探讨人输卵管液和上皮细胞培养液对人精子顶体反应的诱发作用。方法：用Ｈａｍ′ｓＦ１０作对照组，输卵管液和上皮细胞培养液为实验组，分别与生育力组（ｎ＝２０）和不育组（ｎ＝２０）的精子进行共孵育，用精子顶体三色染色法对顶体状态进行评价。结果：共孵育３ｈ时与Ｈａｍ′ｓＦ１０对照组相比较，两种输卵管液均可显著提高生育力组和不育组的精子顶反应率（Ｐ〈０．０５），但这两种输卵管液处理的生育力组与不育组之间     

大熊猫肌红蛋白的纯化及一级结构的研究

本文从大熊猫骨骼肌分离纯化了肌红蛋白,鉴定了纯度,测定了分子量及氨基酸组成。确定了该蛋白的N端及C端氨基酸。采用CNBr裂解的方法,用HPLC分离得到4个肽段,分别测定了大熊猫肌红蛋白1—52位,56—77位及132—153位氨基酸的排列顺序。大熊猫肌红蛋白共含153个氨基酸,本文已完成了96个氨基酸的序列测定。用此结果与食肉目有关动物已知肌红蛋白的氨基酸顺序进行比较,获得了有意义的结论。     

Molecular cloning of cDNA encoding human interleukin-2 receptor

The human interleukin-2 (IL-2) receptor was purified by affinity chromatography using the anti-Tac monoclonal antibody, and its N-terminal amino acid sequence was determined. Complementary DNA clones were isolated and sequenced to reveal the primary structure of the IL-2 receptor precursor, which has 272 amino acid residues. The receptor is separated into two domains by a putative 19-residue transmembrane region. Two mRNAs (1.4 and 3.5 kilobases) hybridizing to the cDNA clone were found in human T cells bearing the IL-2 receptor. The cDNA directed synthesis of the IL-2 receptor in COS cells.     

Homology between human bladder carcinoma oncogene product and mitochondrial ATP-synthase

More than 10 different dominant transforming genes (oncogenes) have been identified in human tumours. A human bladder carcinoma oncogene, closely related in sequence to retroviral transforming genes, is split into four exons; the first encodes the N-terminal 37 residues of p21, a protein of unknown function. The oncogene is activated by a single point mutation (guanine to thymine) resulting in the change glycine to valine at position 12 of p21 (refs 3, 4). We report here that the amino acid sequence surrounding this residue is highly homologous to the beta-subunit of mitochondrial and bacterial ATP-synthase in the region of the polypeptide that is believed to contribute to nucleotide binding. Thus, p21 may form part of an enzyme that uses purine nucleotides in catalysis. This is consistent with the finding that an equivalent murine oncogene product binds GTP.     

蝴蝶兰花发育相关基因pPI9的克隆与表达分析

为研究具有复杂而特异花型的蝴蝶兰花发育的分子机制,利用RT-PCR方法从蝴蝶兰花瓣总RNA中分离出834 bp长的cDNA片断.序列分析表明,该cDNA片断与拟南芥的PI基因有60%的同源性,命名为pPI9.它包含一个开放阅读框,具有编码24.5 ku蛋白质的能力.推导的氨基酸序列中,N端包含一个完整的MADS盒,C端有明显的PI基序.半定量PCR结果表明该基因只在植株的生殖器官中表达,而在营养器官中不表达,推测其可能参与花形态建成过程的调节.     

鹿茸多肽的分离纯化及药理活性

采用凝胶过滤层析、 离子交换层析以及高效液相方法, 从马鹿鲜鹿茸分离得到了一种多肽, 其在SDS-PAGE电泳上显示为一条带, HPLC图谱为单峰, 质谱显示其相对分子量为3　095.1. 氨基酸组成分析结果表明, 此多肽主要含有缬氨酸、 丙氨酸、 赖氨酸和 甘氨酸, 没有半胱氨酸. 经FDNB法测定, 其N-末端氨基酸为缬氨酸. 活性检测表明, 该多肽能够明显促进表皮细胞和BRL肝细胞株的增殖.     

Cloning of a novel gene encoding human thioredoxin-like protein

mRNA differential display (DDRT-PCR) has been used to analyze different human fetal brain tissues of different developmental stages (13- and 33-week). According to the sequence of one EST obtained in this assay, a pair of primers have been designed to screen the arrayed human fetal brain cDNA library. A1 .2-kb cDNA clone has been found. This cDNA consists of an 867 bp open reading frame, a 132 bp 5' untranslated sequence and a 209 bp 3' untranslated sequence with a typical polyadenylation signal. The coding region predicts a protein of 289 amino acids. Its N-terminal of 105 residues is highly homologous to human thioredoxin, while no homology has been found in the databases with its C-terminal of 184 residues. Its N-terminal region also contains the conserved active site sequence CGPC (Cys-Gly-Pro-Cys) of thioredoxin. It was named human Thioredoxin-like gene (hTRXL).     

Molecular cloning of a full-length cDNA for ECBP21 from Angelica dahurica

ECBP21 is an extracellular calmodulin-binding protein which was first detected and purified from extracellular extracts of suspension-cultured cells of Angelica dahurica. The purified protein was electroblotted onto PVDF membrane and the amino acid sequences from 1 to 20 were determined. Using degenerate oligonucleotides of the sequence, a full-length cDNA coding for ECBP21 was isolated by a combination of RT-PCR and 5′-RACE cloning. The cDNA contains 947 nucleotides and codes for a precursor protein of 216 amino acids. The N-terminal 1-25 amino acid sequence is a predicted signal peptide and the other 26-216 amino acid sequence is a mature peptide. The 26-45 amino acid sequence shows identity with the N-terminal amino acid sequence of purified ECBP21 from Angelica dahurica. The fragment of encoding the mature protein was cloned into pET-28b(+) and transformed into E. coli BL21(DE3). A protein with relative molecular mass 21 ku was expressed in E. coli. Using a biotinylated-CaM gel overlay technique, the expression protein was tested for its ability to bind CaM. The results indicated that the expression protein is a Ca2+- dependent CaM-binding protein. Thus, these results further defined the cDNA clone for ECBP21. This work laid a foundation for elucidating biological functions of ECBP21 by using molecular biological means.     

T-cell epitope of the autoantigen myelin basic protein that induces encephalomyelitis

Chronic relapsing paralysis and demyelination within the central nervous system (CNS), features associated with the human disease multiple sclerosis (MS), develop in mice after injection of murine T-cell clones specific for the autoantigen myelin basic protein (MBP). We examined the fine specificity of three independently derived encephalitogenic T-cell clones using synthetic polypeptides derived from portions of the N-terminal sequence of MBP. These clones appear functionally identical; they all respond to an epitope in the N-terminal nine amino acid residues in association with the same class II (I-A) molecules of the major histocompatibility complex (MHC). Both the N-terminal acetyl moiety and the first residue (Ala) are necessary for recognition. Only N-terminal MBP peptides recognized by these clones were found to cause encephalomyelitis (EAE) in vivo. These results show that the N-terminal MBP-specific T lymphocytes that mediate autoimmune encephalomyelitis are a small population with a limited repertoire; they all recognise the same combination of MHC and target.     

Tissue-specific expression of three distinct types of rabbit protein kinase C

We examined the structure of protein kinase C in an attempt to understand the molecular events connecting protein kinase C activation with the cellular response. Rabbit complementary DNA clones coding for three distinct types of protein kinase C, named alpha, beta and gamma, have been identified and sequenced. The deduced amino acid sequence for alpha, beta and gamma (673, 671 and 672 amino acids, respectively) are closely related. Kinases alpha and beta share an identical N-terminal sequence of 621 amino acid residues and their messenger RNAs arise from a single gene. The C-terminal halves of alpha, beta and gamma are protein kinase domains and are highly homologous to other protein kinases. The mRNAs for alpha, beta and gamma are expressed in various tissues with strikingly different tissue specificities. The one for gamma is found ubiquitously among various tissues, while those for alpha and beta predominate in the brain.