抗爪蟾角蛋白单克隆抗体的研究

本实验以非洲爪蟾(Xenopus laevis)成体皮肤角蛋白免疫的BALB/c鼠脾细胞与小鼠Sp2/0骨髓瘤细胞在PEG的作用下进行融合,经HAT选择培养、ELISA筛选、反复克隆化及冻存复苏,获得四株稳定分泌抗体的杂交瘤细胞株。对其中一株杂交瘤细胞KD_(10)及其分泌的抗体进行了较全面的研究。     

A novel type of cardiac calcium channel in ventricular cells

Calcium influx is vital for several aspects of cardiac activity, so it is important to ask if heart cells possess a single or multiple types of Ca channel. Only one Ca channel type has been identified in patch-clamp studies of unitary current, despite suggestions to the contrary from whole-cell recordings in heart cells and unitary recordings from other cells. Here we describe a novel type of cardiac Ca channel with several properties that distinguish it from the hitherto-identified Ca channel in heart cells. Its conductance in isotonic Ba is small (8 pS), and is no larger in Ba than in Ca. It activates and inactivates at relatively negative potentials and remains functional long after patch excision. It is insensitive to dihydropyridines such as nimodipine and the Ca agonist Bay K 8644, and is more resistant to block by external Cd than the previously described type of cardiac Ca channel.     

濒危植物黄山梅及其相关植物的叶表皮特征研究

对黄山梅属(Kirengeshoma Yatabe)黄山梅(Kirengeshoma palmata Yatabe)及其相关植物--草绣球属(Cardiandra Sieb.＆Zucc.)和银梅草属(Deinanthe Maxim.)植物作了叶表皮的微形态研究.结果表明:黄山梅(Kirengeshoma palmata Yatabe)叶下表皮细胞不规则,垂周壁深波状,气孔类型为不规则型;叶上表皮不规则或近多角形,垂周壁平直、弓形或波状.叶上、下表面均具单细胞T形毛,毛上疣突显著.毛基为单细胞型.草绣球(Cardiandra mollendorffii Li)叶下表皮不规则,垂周壁深波状,气孔类型为不规则型;叶上表皮细胞不规则,垂周壁浅波状,具针晶,单毛,具鞘状结构,表面光滑.毛基为多细胞型.二裂叶银梅草(Deinanthe bifida Maxim.)和银梅草(Deinanthe caerulea Stapf.)叶下表皮细胞不规则,垂周壁深波状,气孔类型为不规则型;叶上表皮细胞形状与垂周壁式样同叶下表皮,且均具针晶.另外,在二裂叶银梅草叶上、下表面发现两种类型的毛:锥形毛和T形毛.结合三属的现有资料,通过比较分析,笔者初步认为: 三属性状高度重叠,关系甚密,银梅草属可能是黄山梅属和草绣球属的过渡类型;叶表皮特征观察结果不支持Takhtajan系统把黄山梅独立出来提升为亚科的观点.     

鼻咽癌的角蛋白-粘液组化观察

作者采用同时显示角蛋白和粘液的PAP和ABC免疫组化染色法观察了14例经石蜡包埋的鼻咽癌组织切片,初步结果如下: 1.鼻咽柱状细胞和单纯化生的鳞状细胞均含人体角蛋白.当细胞的核呈异型性变时,角蛋白含量明显减少. 2.鼻咽分化差的鳞癌细胞一般含有角蛋白,虽然各个癌细胞之间含量有差异,但如果采用8型和18型单克隆抗体时,则情况有所不同,一些癌细胞呈阳性而另一些癌细胞则为阴性. 3.在呈异型性变的上皮中仍可找到少数几个粘液细胞,但在癌巢中却未见有粘液细胞. 本文讨论了上述结果在鼻咽癌组织发生学中的意义.     

Is ribonucleotide reductase the transforming function of herpes simplex virus 2?

Transformation of cells by herpes simplex virus 2 (HSV-2) can be induced by the BglII C (0.43-0.58 map units) or N (0.58-0.625) fragments of the viral genome. Sequences partially overlapping both fragments (0.566-0.602) encode two 3' coterminal mRNAs; these in turn direct the synthesis of two related polypeptides of molecular weight 140,000 (140K) and 35K (refs 4, 7), which may be involved in transformation. Recently, a temperature-sensitive (ts) mutation affecting HSV-induced ribonucleotide reductase has been mapped within this common region (B.M. Dutia, personal communication). We have partially purified the induced reductase and raised a rabbit antiserum to it which inhibits the enzyme activity and immunoprecipitates from infected cells a 144K polypeptide and minor species including a 38K polypeptide. Here we show that a monoclonal antibody to the putative transforming proteins competes with the rabbit serum for the 144K and 38K antigens and also immunoprecipitates specifically the induced reductase activity. These results suggest a possible role for ribonucleotide reductase in HSV-2-induced transformation.     

Stimulation of connective tissue cell growth by substance P and substance K

Connective tissue cells proliferate actively when cultured in the presence of serum. Platelet-derived growth factor (PDGF), a basic protein of relative molecular mass approximately 30,000, has been identified as the major serum mitogen for these cells; its main physiological/pathophysiological role may be to initiate wound healing in connection with tissue injury. However, growth of cultured cells is also influenced by several other factors, including epidermal growth factor, fibroblast growth factor, insulin and somatomedins. Furthermore, Rozengurt and Sinnett-Smith recently showed that bombesin, a neuroendocrine peptide isolated from frog skin, stimulates DNA synthesis and cell division in cultures of a specific subtype of 3T3 cells. Substance P and substance K (also known as neurokinin A or neuromedin L) are mammalian peptides belonging to the tachykinin family. Substance P has been studied extensively; it is distributed widely throughout the central and peripheral nervous system, including primary sensory neurones, and can be released in the periphery from axon collaterals of stimulated pain fibres and contribute to the inflammatory response. Substance K is a member of the tachykinin family isolated from mammalian spinal cord; Nawa et al. determined the primary structure of two types of substance P precursors, one of which contained a sequence homologous to substance K, as well as the sequence of substance P. We report here that substance P and substance K stimulate DNA synthesis in cultured arterial smooth muscle cells and human skin fibroblasts, and that this stimulation is inhibited by the substance P-antagonist spantide.     

血管内皮生长因子C嵌合体（CA65）转基因小鼠的建立和分析

将血管内皮生长因子C嵌合体CA65插入角蛋白14（keratin 14,K14）启动子下游,构建了嵌合体CA65转基因表达载体,通过显微注射法建立转基因小鼠.利用特异引物聚合酶链式反应法鉴定转基因小鼠的基因型后,通过逆转录聚合酶链式反应检测嵌合体CA65的表达水平,证实成功建立了皮肤特异表达嵌合体CA65转基因小鼠.对...     

A keratin cytoskeletal protein regulates protein synthesis and epithelial cell growth

Cell growth, an increase in mass and size, is a highly regulated cellular event. The Akt/mTOR (mammalian target of rapamycin) signalling pathway has a central role in the control of protein synthesis and thus the growth of cells, tissues and organisms. A striking example of a physiological context requiring rapid cell growth is tissue repair in response to injury. Here we show that keratin 17, an intermediate filament protein rapidly induced in wounded stratified epithelia, regulates cell growth through binding to the adaptor protein 14-3-3sigma. Mouse skin keratinocytes lacking keratin 17 (ref. 4) show depressed protein translation and are of smaller size, correlating with decreased Akt/mTOR signalling activity. Other signalling kinases have normal activity, pointing to the specificity of this defect. Two amino acid residues located in the amino-terminal head domain of keratin 17 are required for the serum-dependent relocalization of 14-3-3sigma from the nucleus to the cytoplasm, and for the concomitant stimulation of mTOR activity and cell growth. These findings reveal a new and unexpected role for the intermediate filament cytoskeleton in influencing cell growth and size by regulating protein synthesis.     

Lateral inhibition during vulval induction in Caenorhabditis elegans

During Caenorhabditis elegans vulval induction the anchor cell of the gonad specifies a spatial pattern of three cell types among a set of six multipotent epidermal cells, the vulval precursor cells (VPCs). Previous studies suggested that the anchor cell produces a graded inductive signal which can directly stimulate VPCs away from a ground state (type 3) to become type 1 or type 2 depending on their distance from the anchor cell. Here, we investigate the interactions among VPCs in a mutant, lin-15, in which VPC fates are rendered partially independent of the inductive signal, and show that type 1 cells actively inhibit adjacent cells from also becoming type 1 cells. The fate of each VPC therefore depends on the combined action of two intercellular signals: a graded inductive signal from the anchor cell, and a lateral inhibitory signal from at least some of its neighbours. Pattern formation among the VPCs lin-15 mutant is analogous to the establishment of the pattern of neuroblasts and dermatoblasts during early insect neurogenesis, suggesting that the similarities in inferred molecular structure of the lin-12 and Notch gene products, which are involved in these two instances of pattern formation, might extend to similarities in function.     

沙枣(Elaeagnus angustifolia L.)体内、外胚胎发育的比较研究

本文应用经典制片法和离体培养法。对沙枣体内、外胚胎发育的各阶段做比较研究。主要区别于原胚期:1)、形态发生:体内只有一种方式,即两极分化方式。而离体的有二种方式,即器官发生和胚状体发生途径。2)、胚性细胞起源:体内只一种起源(即起源于受精卵),离体的胚性细胞的起源有三种方式:a由紧邻表皮细胞的单个薄壁细胞产生;b由表皮细胞横分裂产生和c由表皮及其下的薄璧细胞共同参与产生。3)胚性细胞的细胞学特征:体内发生的合子具明显的极性分化,细胞质、淀粉粒和细胞核集中在合点端。它第一次分裂后,顶、基细胞在细胞学特征上具明显区别。而离体条件下的胚性细胞第一次分裂后无典型的顶、基细胞之分。故也缺乏典型的胚柄细胞。胚分化和成熟期、二者在形态学特征上基本相同     

Striking similarities between antigen receptor J pieces and sequence in the second chain of the murine CD8 antigen

The CD8 antigen is a marker for T-lymphocyte subsets that is absent from helper T cells but expressed on cytotoxic T cells which recognize foreign determinants in association with class I major histocompatibility complex (MHC) antigens. It has been suggested that CD8 plays some part in recognition by CD8+ cytotoxic T cells since anti-CD8 antibodies can block their functions and the human CD8 antigen contains a domain with clear similarities to immunoglobulin and T-cell receptor (TCR) variable-region (V) domains. Human CD8 antigen is thought to be a homodimer but in the mouse and rat the equivalent antigens (alternatively called Lyt2,3 and OX8) are heterodimeric. Rat CD8 contains two chains of relative molecular mass 32,000 (32K) and 37K: the 32K chain is the rat homologue of human CD8 and mouse Lyt2. We describe here the molecular cloning of the rat 37K chain using an oligonucleotide probe predicted from peptide sequence. The full protein sequence is derived from the complementary DNA and matches limited peptide sequence for mouse Lyt3. The new sequence is more like immunoglobulin and T-cell receptor V domains than other T-cell antigens and includes a patch that is almost identical to some joining (J) piece sequences. This suggests that the CD8 and receptor heterodimers may have evolved directly from a common ancestor.     

根瘤菌诱导紫云英根表面传递细胞的观察

对紫云英无菌苗进行接菌处理，以不接菌为对照。于灭菌无氮培养液中培养1周，在接菌处理的紫云英苗中，取根毛密集、形变明显的根段固定，同时在不接菌对照处理的紫云英苗中，截取相应部位根段固定。两组固定的根段分别进行塑料半薄切片光镜观察和超薄切片透射电镜观察。结果发现：经根瘤菌处理的根段，其根表皮细胞的外切向壁上，发育出大量壁内突结构，甚至在根毛细胞四周也发育出大量的壁内突结构，属典型的传递细胞。经透射电镜观察，这些壁内突结构主要为乳头状和盾状结构。而对照苗的根段内未发现壁内突结构，证明紫云英根表皮传递细胞的形成是由紫云英根瘤菌诱导所致。     

任意多面体重心及积分的精确算法

通过对三维单纯形积分公式的分析给出了其伪代码实现,并结合具体实例描述了其求解过程,给出了任意形状多面体重心计算方法。利用上述算法,对比了中空规则形状多面体重心的计算值与理论值差异,分析了不同边长比（10-4-104）情况下计算值与理论值的差异,讨论了计算结果的精度。通过非规则形状多面体重心计算结果的稳定性分析,讨论了单纯形积分的普适性特征。结果表明,积分和重心的计算值与理论值的相对误差约为10-15-10-14,图形条件对积分结果的影响极小且不存在系统性。因此,单纯形积分结果具有高度的稳定性和精确性。     

纤维的形变和断裂——Ⅰ.拉伸角蛋白纤维形变和断裂的动态研究

作者在扫描电子显微镜样品室中拉伸角蛋白纤维,观察纤维形变和断裂的过程并摄取其照片。采用低加速电压观察和适当的样品准备技术,避免了纤维在拉伸过程中出现荷电现象。该现象是非导电材料作动态观察的主要困难。从所观察到的纤维形变和断裂形态和高聚物断裂理论讨论了角蛋白纤维的形变和断裂机理。结论如下:角蛋白纤维伸长和断裂过程中出现银纹样形态,但其断裂为脆性方式;该类纤维的拉伸断裂起始于角质细胞的内、外角质层;角质与角质和角质与皮质细胞间的物质是角蛋白纤维的力学薄弱区。     

Neural subsystems for object knowledge.

Critical issues in the cognitive neuroscience of language are whether there are multiple systems for the representation of meaning, perhaps organized by processing system (such as vision or language), and whether further subsystems are distinguishable within these larger ones. We describe here a patient (K.R.) with cerebral damage whose pattern of acquired deficits offers direct evidence for a major division between visually based and language-based higher-level representations, and for processing subsystems within language. K.R. could not name animals regardless of the type of presentation (auditory or visual), but had no difficulty naming other living things and objects. When asked to describe verbally the physical attributes of animals (for example, 'what colour is an elephant?'), she was strikingly impaired. Nevertheless, she could distinguish the correct physical attributes of animals when they were presented visually (she could distinguish animals that were correctly coloured from those that were not). Her knowledge of input stimulus. To explain this selective deficit, these data mandate the existence of two distinct representations of such properties in normal individuals, one visually based and one language-based. Furthermore, these data establish that knowledge of physical attributes is strictly segregated from knowledge of other properties in the language system.     

Bovine papillomavirus E5 oncoprotein binds to the 16K component of vacuolar H(+)-ATPases.

The major transforming protein of bovine papillomavirus type 1, E5, is mainly associated with endomembranes, specifically binding to a cellular protein of relative molecular mass 16,000 (16K). At the same time as transformation, E5 causes the phosphorylation of tyrosine residues in epidermal and platelet-derived growth factor receptors. We show here that the 16K protein associated with E5 is the 16K component of vacuolar ATPases. This protein is known to be an integral membrane protein in endosomes, bovine chromaffin granules, synaptic vesicles, fungal and plant vacuoles and clathrin-coated vesicles, as well as a component of gap-junction-like membrane complexes. Because proton pumps are critical for the function of cellular compartments that process growth-factor receptors, the interaction of E5 with the 16K protein could explain the pleiomorphic features of cells transformed by E5.     

螺旋多肽链中的孤子与生物现象

提出一个描述螺旋多肽链的氢键链间耦合模型。得到了扭结团,包络孤子团和呼吸子团。其中对称和非对称扭结团分别对应于螺旋多肽链的压缩（或扩张）和扭曲变形区。     

SWAP-70 is a guanine-nucleotide-exchange factor that mediates signalling of membrane ruffling

Phosphoinositide-3-OH kinase (PI(3)K), activated through growth factor stimulation, generates a lipid second messenger, phosphatidylinositol-3,4,5-trisphosphate (PtdIns(3,4,5)P3). PtdIns(3,4,5)P3 is instrumental in signalling pathways that trigger cell activation, cytoskeletal rearrangement, survival and other reactions. However, some targets of PtdIns(3,4,5)P3 are yet to be discovered. We demonstrate that SWAP-70, a unique signalling protein, specifically binds PtdIns(3,4,5)P3. On stimulation by growth factors, cytoplasmic SWAP-70, which is dependent on PI(3)K but independent of Ras, moved to cell membrane rearrangements known as ruffles. However, mutant SWAP-70 lacking the ability to bind PtdIns(3,4,5)P3 blocked membrane ruffling induced by epidermal growth factor or platelet-derived growth factor. SWAP-70 shows low homology with Rac-guanine nucleotide exchange factors (GEFs), and catalyses PtdIns(3,4,5)P3-dependent guanine nucleotide exchange to Rac. SWAP-70-deficient fibroblasts showed impaired membrane ruffling after stimulation with epidermal growth factor, and failed to activate Rac fully. We conclude that SWAP-70 is a new type of Rac-GEF which, independently of Ras, transduces signals from tyrosine kinase receptors to Rac.