Organization of the multifunctional neural network regulating visceral organs inHelix pomatia L (Mollusca,Gastropoda)

Summary InHelix pomatia L. the overlapping neuronal network was found to regulate the visceral functions (e.g. cardiorenal, respiratory and genital functions). The neural network is organized around the multifunctional interneurons, which take part in forming both afferent and efferent pathways. The interneurons are sensitive to a wide range of neurotransmitters or transmitter candidates including low molecular weight substances (ACh, 5HT, DA, octopamine, glutamate) and several oligopeptides. In this system both selection of information and modification of membrane properties (for example habituation) are carried out by a combination of simultaneously liberated active agents.     

Nervous control of smooth muscle by transmitters,cotransmitters and modulators

Conclusion The part played by peripheral neuroeffector control mechanisms has been underestimated. These are additional to central and ganglionic control mechanisms and are much more elaborate than originally thought. While the classical view is that the autonomic nervous system consists largely of antagonistic cholinergic and adrenergic nerves, about sixteen putative neurotransmitters have been proposed in autonomic nerves in the past few years, including various monoamines, polypeptides, purines and amino acids. Modulatory transmitter mechanisms have also been recognized, including prejunctional inhibition or enhancement of transmitter release, postjunctional modulation of transmitter action, and the secondary involvement of locally synthesized hormones and prostaglandins. The existence of more than one transmitter substance in some nerves is now widely recognized, and suggestions have been made about the ways that this can lead to differential peripheral control mechanisms at nerve terminals themselves. The cotransmitters always have synergistic actions on postjunctional effector cells, but two different operating mechanisms are postulated. 1) If both substances are stored in the same vesicles (for example, ACh or NA with ATP), release is closely parallel at all impulse frequencies. Upon release, the cotransmitter, in addition to having a direct action on postjunctional cells, may facilitate the action of the other transmitter and/or act as an inhibitor of its release. Differential actions at different impulse frequencies are achieved post-junctionally by ATP and NA acting via EJP-spike and spike-independent mechanisms, respectively. 2) If the two substances are stored in separate vesicle types (for example ACh or NA with some peptides), then differential release is possible at different impulse frequencies; the peptides released at higher frequencies modulate the role of the classical transmitter, by both prejunctional enhancement of its release and post-junctional facilitation of its action.     

Lipopeptaibols, a novel family of membrane active, antimicrobial peptides

Lipopeptaibols are members of a novel group of naturally occurring, short peptides with antimicrobial activity, characterized by a lipophilic acyl chain at the N-terminus, a high content of the turn/helix forming α-aminoisobutyric acid and a 1,2-amino alcohol at the C-terminus. The amino acid sequences range from 6 to 10 residues and the fatty acyl moieties from 8 to 15 carbon atoms. The peptide portion of lipopeptaibols can be shorter than those of the nonlipidated peptaibols that range from 10 to 19 amino acid residues. The longest peptides fold into a mixed 3₁₀/α helix, whereas the shortest peptides tend to adopt a β-turn/sheet structure. Using solution methodologies, a series of analogues of trichogin GA IV was synthesized which allowed determination of the minimal lipid chain and peptide main-chain lengths for the onset of membrane activity and exploitation of a number of spectroscopic techniques aimed at determining its preferred conformation under a variety of conditions and investigating in detail its mode of interaction with, and its effect on, the phospholipid membranes. Received 26 January 2001; received after revision 7 March 2001; accepted 15 March 2001     

福建老酒中血管紧张素转换酶抑制物质的分离鉴定

福建老酒的样品经在ＴｏｙｏｐｅａｒｌＨＷ４０５凝胶过滤色谱柱分离成包括蛋白质、肽、乙醇和糖类等５个主要组分，其中含肽类物质的第二组分显示出较强的ＡＣＥ抑制活性，该组分经ＳｕｐｅｒｄｅｘＰｅｐｔｉｄｅＨＲ１０／３０进一步分离纯化，获得３个组分．其中的第二及第三组分具有ＡＣＥ抑制活性，其ＩＣ（５０）分别为２．８及８．１μｇＰｒｏｔｅｉｎ／ｍＬ，而分子量则为１１００和４５０．     

食品蛋白质中血管紧张素转化酶抑制肽的研究

血管紧张素转化酶I在人体血压调节过程中起重要的生理作用．一方面,它使无活性的血管紧张素I转化为升压物质——血管紧张素Ⅱ,另一方面它能使降压物质——缓激肽分解成失活片段．源于食品蛋白质中的降压肽有明显的降血压作用,这些肽又是通过抑制血管紧张素转化酶的活性起降血压作用．综述血管紧张素转化酶抑制肽的降血压机理和研究现状,展望其前景．     

Antimicrobial and cytolytic peptides of venomous arthropods

As a response to invading microorganisms, the innate immune system of arthropods has evolved a complex arrangement of constitutive and inducible antimicrobial peptides that immediately destroy a large variety of pathogens. At the same time, venomous arthropods have developed an additional offensive system in their venom glands to subdue their prey items. In this complex venom system, several enzymes, low-molecular-mass compounds, neurotoxins, antimicrobial and cytolytic peptides interact together, resulting in extremely rapid immobilization and/or killing of prey or aggressors. This review provides an overview of antimicrobial peptides identified in the hemolymph of venomous arthropods, and especially of cytolytic peptides in their venom. For these peptides a dual role is proposed: acting as antimicrobials as well as increasing the potency of the venom by influencing excitable cells.Received 17 March 2003; received after revision 11 June 2003; accepted 17 June 2003     

分子印迹技术在多肽、蛋白质分离中的应用

介绍了分子印迹聚合物(Molecularly Imprinted Ploymer,MIP)在分离生物大分子——多肽、蛋白质等领域中的应用进展，及其发展前景。     

草鱼日粮中虾蛋白肽对幼龄草鱼生长性能的影响

用300尾(3.74±0.23)g的草鱼Ctenopharyngodon idella作日粮中不同添加量虾蛋白肽(平均肽链长为3.61)对幼龄草鱼生长性能影响研究.实验分为4组,每组75尾鱼,每25尾鱼饲于0.25m3的水族箱中,每组设3个平行水族箱.试验1、2、3组日粮中分别添加w为0.25%虾蛋白肽 w为0.75%鱼粉、w为0.5%虾蛋白肽 w为0.5%鱼粉、w为1%虾蛋白肽,对照组添加w为1%鱼粉.试验期56 d.结果表明:试验各组草鱼其特定生长率、蛋白保留效率、饲料系数和血浆中磷、镁含量与小肽总量均高于对照组,特别是试验2、3组与对照组有显著性差异(P＜O.05);草鱼日粮中适宜的虾蛋白肽添加量为w为0.5%.草鱼日粮中添加一定比例的虾蛋白肽均可提高饲料表观消化率和蛋白消化率,增加血液循环中生物活性肽的含量,提高机体对日粮中氨基酸的利用率,从而增加体内氮沉积,减少肝胰脏和肠系膜脂肪储积.     

降钙素基因相关肽和内皮素-1对支气管上皮细胞与嗜酸性粒细胞黏附功能的影响

观察肺内调节肽对嗜酸性粒细胞(EOS)与支气管上皮细胞(BEC)粘附功能的影响.选择降钙素基因相关肽(CGRP)和内皮素-1(ET-1)两种调节肽作为研究对象,观察它们对BEC白细胞介素(ILs)分泌及细胞间粘附分子-1(ICAM-1)表达的影响.结果表明:CGRP,ET-1可使O3应激的BEC分泌ILs能力升高,并上调气道上皮ICAM-1的表达.CGRP、ET-1能促进BEC与EOS的粘附,对气道炎症起正性调节作用,加重局部的损伤.