人胎盘低分子量神经生长因子（hNGF）的分离、纯化和性质鉴定

将从小鼠颌下腺中分离纯化神经生长因子（ＮＧＦ）的方法运用于胎盘,通过中性搅拌抽提,两次ＣＭ－５２阳离子交换层析柱和一次ＳｅｐｈａｄｅｘＧ－７５凝胶过渡得到一纯度和比活都比较高的,可促进神经节生长的碱性蛋白质,通过免疫学（Ｗｅｓｔｅｒｎ－ｂｌｏｔｔｉｎｇ）和生物学性质（可以促进鸡胚背根神经节出神经纤维）的鉴定,确定此物是人为一种低分子量的神经生长因子（ｈＮＧＦ）。     

中华眼镜蛇毒神经生长因子的研究

采用ＣＭ－ＳｅｐｈａｒｏｓｅＣＬ－６Ｂ和ＳｅｐｈｏｓｉｌＣ８以及ＨＰＬＣ层析方法，自广西产中华眼镜蛇毒中分离纯化神经生长因子（ＮＧＦ），此ＮＧＦ经８ｄ鸡胚背根神经节体外培养证明具有促进神经纤维生长的活性。经ＨＰＬＣ及聚丙烯酰胺凝胶电泳鉴定为单一组成，经ＳＤＳＰＡＧＥ及ＨＰＬＣ测定分子量分别为２４．１ＫＤ和２４．９ＫＤ，等电聚焦电泳测得ｐＩ为８．２，氨基酸组分分析表明ＮＧＦ含酸性氨基酸较少，通过１２５｜标记ＮＧＦ测定出ＮＧＦ在生物体内主要分布于肾、肺、及周围神经     

ELISA对毒理实验动物血清中神经生长因子抗体动态的研究

用ＥＬＩＳＡ法对神经生长因子（ＮＧＦ）毒理实验动物犬和大鼠血清作了抗－ＮＧＦ抗体检测。结果表明在大鼠血清中没有发现抗－ＮＧＦ抗体,但犬血清中有相应的抗体产生,并随注射剂量增加和注射时间延长而逐渐升高,另外,对ＥＬＩＳＡ间接法和竞争抑制法进行了比较,结果表明,竞争抑制法明显优于间接法,而且是一种简便、特异的好方法。     

蛇毒神经生长因子的分离纯化及鉴定

采用Ｓｅｐｈａｄｅｘ Ｇ５０、ＣＭ－Ｃｅｌｌｕｌｏｓｅ ３２柱层析，从中华眼镜蛇中分离出神经生长因子（Ｎｅｒｖｅ Ｇｒｏｗｔｈ Ｆａｃｔｅｒ，ＮＧＦ）。经ＳＤＳ－聚丙烯酰胺凝胶电泳及Ｗｅｓｔｅｒｎ ｂｌｏｔｔｉｎｇ法证明所得以的ＮＧＦ为单一组分，相对分子质量约为１．３×１０＾４。经凝胶等电聚焦电泳测得ＮＧＦ等电点ＰＩ约为７．０左右。经ＨＰＬＣ及电泳图像分析系统测得纯度为９８％。此ＮＧＦ等８ｄ鸡胚背     

舞毒蛾非线性模型及其动态

从森林－舞毒蛾－寄生天敌系统的相互作用机理出发,组建了描述这个系统动力学行为的非线性离散模型：Ｆｔ＋１＝Ｆｔｅｘｐ（ｒ－ｒ（Ｆｔ＋ｂｃＧｔ）／Ｋ）,Ｇｔ＋１＝ｓＧ１ｅｘｐ（ｍ（ａＦ－ｃＧ）／Ｋ－ｑ１Ｐｔ）,Ｐｔ＋１＝ｗＧｔ（１－ｅｘｐ（－ｑＲｔ））,讨论了模型的平衡态及其稳定性以及舞毒蛾的非线性动力学行为,分析和模拟结果与舞毒蛾的动态行为是一致的,同时通过对模型的时间态动态以及各参数变化对模型动态     

光纤陀螺的研究现状及发展趋势

综述了光纤陀螺的最新进展,并着重介绍了中、低性能干涉式光纤陀螺（Ｉ－ＦＯＧ）的应用情况和高性能Ｉ－ＦＯＧ、谐振腔光纤陀螺（Ｒ－ＦＯＧ）以及布里渊光纤陀螺（Ｂ－ＦＯＧ）的研究状况．     

子群或商群均为局部（π—q）群的有限群

令Ｆ（ Ｇ） 表示群Ｇ 的Ｆｉｔｔｉｎｇ 子群。若Ｇ 的每个含于Ｆ（ Ｇ） 的子群与Ｇ 的所有Ｓｙｌｏｗ 子群可交换,则称Ｇ是局部（π－ ｑ） 群。局部（ π－ ｑ） 群的子群和商群未必是局部（ π－ ｑ） 群。本文研究了子群或商群仍为局部（ π－ ｑ） 群的有限群,给出了它的结构。     

神经生长因子抗体亲和柱的制备与应用

利用已分离纯化的神经生长因子为抗原,制备兔抗ＮＧＦ抗血谱,用饱和（ＮＨ４）２ＳＯ４盐析和Ｐｒｏｔｅｉｎ Ａ亲和层析的方法,纯化其中的ＩｇＧ组分,再将其偶联到ＣＮＢｒ活化的Ｓｅｐｈａｒｏｓｅ ４Ｂ上,制备抗ＮＧＦ ＩｇＧ免疫亲和性,应用此亲和柱可一步纯化蛇毒中的ＮＧＦ,大大简化了ＮＧＦ纯化工艺。     

用逻辑方程解集关系求逻辑方程组的解集

给出了逻辑方程ｍｉ＝１（Ｆｉ＋Ｇ－ｉ）＝１,ｍｉ＝１　ＦｉＧ－ｉ＝１及逻辑方程组Ｆ１＝Ｇ１,Ｆｍ＝Ｇｍ的解集关系定理,得到了如下结论：若逻辑方程ｍｉ＝１（Ｆｉ＋Ｇ－ｉ）＝１和ｍｉ＝１　ＦｉＧ－ｉ＝１解集分别为Ｓ１和Ｓ２,则逻辑方程组Ｆ１＝Ｇ１,Ｆｍ＝Ｇｍ的解集为Ｓ１－Ｓ２．     

关于有限群GF（2）──模的若干结果

有限群的ＧＦ（Ｐ）－模特别是ＧＦ（２）－模的研究是有限群论研究工作的一个重要方面，本文利用有限群论的基本理论和方法讨论了置换群∑３和∑６的ＧＦ（２）－模的结构。     

Amino acid sequence of rat submaxillary tonin reveals similarities to serine proteases

Tonin, an esteroprotease isolated from rat submaxillary gland, is a serine protease with trypsin- and chymotrypsin-like activity. The substrate specificity of tonin shows that it differs from kallikreins and is definitely not a renin-like enzyme or an angiotensin-converting enzyme. Tonin can produce directly the vasoactive peptide angiotensin II, from angiotensin I, angiotensinogen and the synthetic tetradecapeptide substrate of renin by cleavage of a Phe-His bond. It has also been found to cleave some Phe and Arg bonds in various substrates such as beta-lipotropin (beta-LPH), adrenocorticotropin (ACTH), pro-opiomelanocortin (POMC) and substance P. Here we describe the complete amino acid sequence of rat submaxillary gland, tonin. Comparison of the sequence of 219 amino acids with other serine proteases, particularly kallikreins, gamma-subunit of nerve growth factor (NGF) and the recently described gamma-renin, reveals extensive similarities. More interestingly, it also reveals the substitution of an Asp residue always found in the serine protease active site triad (Asp, His, Ser) by a Leu residue. This unusual substitution does not seem to affect the proteolytic activity of the enzyme.     

Stimulation of the pituitary-adrenocortical axis by nerve growth factor.

Nerve growth factor (NGF) is a protein essential for the development and maintenance of the peripheral sympathetic nervous system, causing responsive neurones to increase in size and to extend neurites. Biochemically, the selective induction of tyrosine hydroxylase (TH) and dopamine beta-hydroxylase key enzymes in catecholamine biosynthesis is one of its most characteristic effects. Both the morphological and biochemical effects are modulated by glucocorticoids, suggesting a close relationship between specific effects of NGF and hormone action. NGF has been shown to induce an increase in adrenal cyclic AMP in intact but not in hypophysectomised rats, and so we have looked directly at the effect of systemic administration of NGF on the hypothalamo-pituitary-adrenal axis. We report here that NGF induced an enhanced secretion of adrenocorticotropin (ACTH) and a prolonged increase in plasma glucocorticoid concentration after intravenous (i.v.) injection. Such effects could have important implications for the biological activity of NGF.     

Desensitisation of cultured glial cells to epidermal growth factor by receptor down-regulation.

Epidermal growth factor (EGF), which can be purified from the mouse submaxillary gland or from pregnant human urine, is a potent multiplication-stimulating factor for several types of cultured cells, including human fibroblasts and glial cells. The molecule binds with high affinity and saturation kinetics to a cell-surface receptor, is subsequently internalised and finally degraded. The binding event is accompanied by a reduction in the number of EGF receptors. This phenomenon--'receptor down-regulation'--has been demonstrated with several hormones and may be a general principle for the modulation of binding groups on the outer cell surface. Further, it has been proposed that receptor loss acts to regulate the cellular response to the binding ligand. The present study provides direct experimental support for this hypothesis. It demonstrates that down-regulation of EGF receptors on glial cells causes desensitisation of the mitogenic response of these cells to subsequent stimulation with EGF.     

Nerve growth factor regulates expression of neuropeptide genes in adult sensory neurons

Nerve growth factor (NGF) is a trophic molecule essential for the survival of sympathetic and sensory neurons during ontogeny. The extent to which NGF is involved in the maintenance or regulation of the differentiated phenotypes of mature peripheral neurons is much less clear, however. Biochemical analysis of the actions of NGF upon peripheral neurons has been hampered by the lack of a preparation of neuronal cells that are responsive to NGF but do not require it for survival. We report here that in adult dorsal root ganglion neurons, which can be isolated, enriched and maintained in culture in the absence of neuronal growth factors, the expression of mRNAs encoding the precursors of two neuropeptides, substance P and calcitonin gene-related peptide is regulated by NGF. Our results provide the first direct evidence of a continuous dynamic role for NGF in regulation of peptide neurotransmitter/neuromodulator levels in mature sensory neurons.     

Mouse prepro-epidermal growth factor synthesis by the kidney and other tissues

Epidermal growth factor (EGF), a protein comprising 53 amino acids, is derived from a precursor of 1,217 amino acids that includes at least seven EGF-like sequences. EGF has diverse biological activities: it is a potent mitogen for many tissue culture cells, inhibits gastric acid secretion from the intestinal mucosa and promotes healing of the corneal epithelium. EGF given to fetal animals accelerates several developmental processes including palate formation, incisor eruption, eyelid opening and lung maturation. However, the physiological roles of EGF in vivo are unknown. The presence of high-affinity receptors in many fetal and adult tissues suggests that EGF is involved in normal cellular functions. Immunocytochemical studies have revealed the presence of EGF in mouse and human submaxillary glands, rat brain and human intestine. The low levels of EGF in extracts from many tissues may reflect sequestration rather than synthesis of the polypeptide. We show here that several mouse tissues contain preproEGF mRNA and that it is synthesized mainly in the distal tubules of the kidney. PreproEGF does not seem to be processed to EGF or other peptides in this tissue.     

BDNF is a neurotrophic factor for dopaminergic neurons of the substantia nigra

Brain-derived neurotrophic factor (BDNF), present in minute amounts in the adult central nervous system, is a member of the nerve growth factor (NGF) family, which includes neurotrophin-3 (NT-3). NGF, BDNF and NT-3 all support survival of subpopulations of neural crest-derived sensory neurons; most sympathetic neurons are responsive to NGF, but not to BDNF; NT-3 and BDNF, but not NGF, promote survival of sensory neurons of the nodose ganglion. BDNF, but not NGF, supports the survival of cultured retinal ganglion cells but both NGF and BDNF promote the survival of septal cholinergic neurons in vitro. However, knowledge of their precise physiological role in development and maintenance of the nervous system neurons is still limited. The BDNF gene is expressed in many regions of the adult CNS, including the striatum. A protein partially purified from bovine striatum, a target of nigral dopaminergic neurons, with characteristics apparently similar to those of BDNF, can enhance the survival of dopaminergic neurons in mesencephalic cultures. BDNF seems to be a trophic factor for mesencephalic dopaminergic neurons, increasing their survival, including that of neuronal cells which degenerate in Parkinson's disease. Here we report the effects of BDNF on the survival of dopaminergic neurons of the developing substantia nigra.     

Crystal structure of nerve growth factor in complex with the ligand-binding domain of the TrkA receptor.

Nerve growth factor (NGF) is involved in a variety of processes involving signalling, such as cell differentiation and survival, growth cessation and apoptosis of neurons. These events are mediated by NGF as a result of binding to its two cell-surface receptors, TrkA and p75. TrkA is a receptor with tyrosine kinase activity that forms a high-affinity binding site for NGF. Of the five domains comprising its extracellular portion, the immunoglobulin-like domain proximal to the membrane (TrkA-d5 domain) is necessary and sufficient for NGF binding. Here we present the crystal structure of human NGF in complex with human TrkA-d5 at 2.2 A resolution. The ligand-receptor interface consists of two patches of similar size. One patch involves the central beta-sheet that forms the core of the homodimeric NGF molecule and the loops at the carboxy-terminal pole of TrkA-d5. The second patch comprises the amino-terminal residues of NGF, which adopt a helical conformation upon complex formation, packing against the 'ABED' sheet of TrkA-d5. The structure is consistent with results from mutagenesis experiments for all neurotrophins, and indicates that the first patch may constitute a conserved binding motif for all family members, whereas the second patch is specific for the interaction between NGF and TrkA.     

Nucleotide sequence of epidermal growth factor cDNA predicts a 128,000-molecular weight protein precursor

Epidermal growth factor (EGF) has a profound effect on the differentiation of specific cells in vivo, and has been shown to be a potent mitogenic factor for a variety of cultured cells, of both ectodermal and mesodermal origin (see ref. 1 for review). This 53-amino acid polypeptide of known sequence contains six cysteine residues, which are thought to form three intrachain disulphide bonds. Urogastrone, a polypeptide bearing anti-gastric secretory activity isolated from human urine, which is presumably synthesized in submandibular and Brunner's glands, shares extensive sequence homology (70%) with EGF and may represent the human EGF equivalent. Here we present the sequence of a mouse EGF cDNA clone, which suggests that EGF is synthesized as a large protein precursor of 1,168 amino acids. Our data indicate that the discrepancy between EGF levels in male and female mouse submaxillary glands (MSGs) is due to different EGF mRNA levels in these tissues, and suggest that precursor EGF processing may differ from that described previously for other polypeptide hormones.     

Immunohistochemical localization of endogenous nerve growth factor

Nerve growth factor (NGF) has been proposed as a trophic molecule essential for the development of sympathetic and primary sensory neurones. In newborn mice and rats, administration of nerve growth factor results in an increase in the number of surviving neurones, whereas administration of antiserum to NGF decreases neuronal survival. Thus it has been proposed that the factor is produced and secreted by the relevant target tissues to provide trophic support for the ingrowing nerves. The site of synthesis of nerve growth factor is still unknown, and it has been emphasized that a precise physiological role for the molecule cannot be ascribed until the cell types that produce it are known. I report here the use of immunohistochemistry to localize endogenous NGF in the rat iris, a tissue in which there is sound biochemical evidence for the production of NGF activity. Surprisingly, the results reveal that NGF can be detected readily in Schwann cells, but not in smooth muscle cells of the iris when it is sympathetically denervated or cultured.