两栖类动物皮肤抗菌肽研究进展

两栖类动物的皮肤在自然进化过程中形成了抵御病原微生物感染的三套防御系统,而皮肤抗菌肽是其先天性免疫系统的重要组成部分.抗菌肽广泛存在于动、植物体内,由基因编码、核糖体合成,能够有效的抑制和杀灭病原微生物,在进化上是一类非常古老而有效的天然防御物质.从两栖类动物皮肤抗菌肽的结构、作用机制、活性功能等方面进行阐述,以期系统认识和了解两栖类动物皮肤抗菌肽,并为其应用研究提供理论依据.     

Brain peptides as neurotransmitters

Numerous peptides appear to be neurotransmitter candidates in the brain. Some, such as the opioid peptide enkephalins, neurotensin, and substance P, were first isolaterd from the brain. Peptides, such as cholecystokinin and vasoactive intestinal polypeptide, were known as intestinal hormones and later recognized as brain constituents. Certain hypothalamic-releasing hormones, pituitary peptides, and blood-derived peptides like angiotensin II and bradykinin, may also be central neurotransmitters. The diversity of localization of these peptides throughout the brain implies a multiplicity of potential roles.     

离子通道特异性药物对昆虫ENF肽诱导家蚕麻痹的影响

昆虫ENF肽是一类存在于鳞翅目昆虫中,一级结构非常保守的多肽,具有诱导昆虫麻痹、血细胞扩散、抑制幼虫生长等多种生物学功能,其作用机制还不清楚.天蚕麻痹肽(Antheraea yamamai paralytic peptide,AnyPP)是昆虫ENF肽家庭成员之一.作者利用合成的天蚕麻痹肽,探讨离子通道的特异性药物在AnyPP诱导家蚕麻痹中的作用.结果表明,BK通道的特异性抑制剂IbTX可以减缓AnyPP对家蚕麻痹的诱导作用,暗示ENF肽诱导家蚕麻痹过程可能有BK通道的参与.结扎试验表明,ENF肽诱导家蚕麻痹与中枢神经系统的传导调节无关.     

抗菌肽作用机制及其在畜禽养殖中应用

抗菌肽又称宿主防御肽,是一种具有广谱抗菌活性小肽类物质,是生物先天免疫系统的重要组成部分。抗菌肽具有抗细菌,抗真菌、抗寄生虫、抗病毒、抗癌细胞和免疫调节等功能,与抗生素作用机制不同,不易产生耐药性,有望成为抗生素替代品,在畜禽生产中应用广泛。文章综述抗菌肽作用机制及其在畜牧养殖中的应用,初步探讨抗菌肽作为抗生素替代物的应用前景。     

Autologous peptides constitutively occupy the antigen binding site on Ia

Low molecular weight material associated with affinity-purified class II major histocompatibility complex (MHC) molecules of mouse (Ia) had the expected properties of peptides bound to the antigen binding site of Ia. Thus, the low molecular weight material derived from the I-Ad isotype was efficient in inhibiting the binding of 125I-labeled I-Ad-specific peptide to I-Ad, but did not significantly inhibit the binding of an I-Ed-specific peptide to I-Ed; the reciprocal isotype-specific inhibition was demonstrated with low molecular weight material derived from I-Ed. The inhibitory material was predominantly peptide in nature, as shown by its susceptibility to protease digestion. It was heterogeneous as measured by gel filtration (mean molecular weight approximately 3000), and when characterized by high-performance liquid chromatography, it eluted over a wide concentration of solvent. Such self peptide-MHC complexes may have broad significance in the biology of T cell responses, including generation of the T cell repertoire, the specificity of mixed lymphocyte responses, and the immune surveillance of self and nonself antigens in peripheral lymphoid tissues.     

An alternative bactericidal mechanism of action for lantibiotic peptides that target lipid II

Lantibiotics are polycyclic peptides containing unusual amino acids, which have binding specificity for bacterial cells, targeting the bacterial cell wall component lipid II to form pores and thereby lyse the cells. Yet several members of these lipid II-targeted lantibiotics are too short to be able to span the lipid bilayer and cannot form pores, but somehow they maintain their antibacterial efficacy. We describe an alternative mechanism by which members of the lantibiotic family kill Gram-positive bacteria by removing lipid II from the cell division site (or septum) and thus block cell wall synthesis.     

抗菌肽及其应用前景概述

抗菌肽是生物体产生的一种具有抗菌活性的多肽类物质,它对细菌、真菌和病毒等都具有明显的杀伤作用.抗菌肽有望开发成为防治人和动物疾病的药物,应用前景广阔.文章对抗菌肽的结构特征、作用机制及应用前景进行了综述,以期为抗菌肽的更深层次的研究与应用提供参考.     

蛋清源生物活性肽功能及其构效关系研究进展

禽蛋为人类提供了丰富的营养物质,如蛋白质、脂质和维生素等。蛋清蛋白不仅具有许多功能性质,通过酶法制备获得的蛋清肽还具有丰富的生物活性。然而,通过水解得到的蛋清源生物活性肽往往具有多种生物活性,且产量较低、结构差异较大,难以获得普适的活性-结构关系结论。本文以鸭蛋蛋清蛋白和鸡蛋蛋清蛋白为对象,综述了蛋清肽的主要生物学功能如降血压、抗氧化、促进矿物质吸收、降血糖、调节肠道健康等,探讨了其结构-活性关系,并对蛋清源生物活性肽的后续深入研究进行了展望,以期为蛋清蛋白的高值化利用提供参考。     

鱼蛋白小肽螯合锌对小鼠的补锌效果及抗氧化作用

以昆明种小鼠(Mus musculus)为试验材料,观察鱼蛋白小肽螯合锌对小鼠的补锌和抗氧化作用,研究鱼蛋白小肽螯合锌的生物活性.结果表明:鱼蛋白小肽螯合锌可以明显提高小鼠肝脏、血清中的锌含量,显著降低小鼠肝匀浆中丙二醛含量,提高总抗氧化能力.鱼蛋白小肽螯合锌具有明显的补锌效果和抗氧化效果,效果优于同剂量的葡萄糖酸锌或...     

抗菌肽抗细菌机理研究进展

抗菌肽是一类有望解决全球范围内抗生素耐药性问题的新型抑菌多肽。抗菌肽主要有3种抑菌机制:其一是针对细菌细胞膜作用,膜作用主要针对两种不同菌膜结构特性的细菌,革兰氏阴性菌外膜富含脂多糖,革兰氏阳性菌细胞壁富含磷壁酸,抗菌肽可靶向作用于此类细菌菌膜结构特定组分。此外,抗菌肽可抑制细菌生物被膜形成,分解已形成细菌生物被膜。抗菌肽作用于特异性酶或靶向作用于DNA产生抑菌效果,其抑制作用可抵抗细菌耐药性产生。基于抗菌肽改变菌膜结构并抑制细菌外膜及酶合成的特性,此杀菌策略已应用于抗菌药物设计。     

Immunogenicity of synthetic peptides from circumsporozoite protein of Plasmodium falciparum

In a study of recombinant proteins that might be useful in developing a vaccine against malaria, synthetic peptides from the circumsporozoite (CS) protein of Plasmodium falciparum were found to be immunogenic for mice and rabbits. Antibody to peptides from the repeating region of the CS protein recognized native CS protein and blocked sporozoite invasion of human hepatoma cells in vitro. Antibodies to peptides from regions I and II had no biologic activity, although antibody to region I recognized processed CS protein by Western blot analysis. These data support the feasibility of developing a vaccine against the sporozoite stage of the malaria parasite by using synthetic peptides of the repeating region of the CS protein conjugated to a carrier protein.     

Purification and sequence analysis of bioactive atrial peptides (atriopeptins)

Mammalian cardiac atria have several biologically active peptides that exert profound effects on sodium excretion, urine volume, and smooth muscle tone. In the present study two such peptides of low molecular weight were purified and separated from each other on the basis of differences in charge, hydrophobicity, and biological profile. The first peptide, designated atriopeptin I, exhibits natriuretic and diuretic activity and selectivity relaxes intestinal smooth muscle but not vascular smooth muscle strips. The second peptide, atriopeptin II, is a potent natriuretic and diuretic that relaxes both intestinal and vascular strips. Sequence analysis of atriopeptin I indicates that it is composed of 21 amino acids, of which serine and glycine residues predominate. The amino terminal sequence of atriopeptin II up to residue 21 is the same as that of atriopeptin I, with the addition of the Phe-Arg extension at the carboxyl terminus. Both peptides appear to be derived from a common high molecular weight precursor (designated atriopeptigen); their biological selectivity and potency may be determined by the site of carboxyl terminal cleavage.     

抗癌肽改造及其对人乳腺癌MCF7作用的评估

为了探讨不同净电荷及疏水度对天然多肽CMAP-8衍生物抗人乳腺癌细胞MCF7增殖抑制作用的影响,分别采用带正电荷的K和疏水性的F两种氨基酸对天然多肽CMAP-8进行设计改造,得到系列衍生物。其净电荷数为0~8,疏水度为42%~57%,采用MTT法检测所得多肽衍生物对人乳腺癌细胞MCF7的增殖抑制率,Anti CP对多肽抗癌活性的预测。结果表明,净电荷为0的多肽均没有预测抗肿瘤活性,可能是因为多肽的净电荷对其预测活性有一定的影响。体外抗乳腺活性结果表明,CMAP-L-20、CMAP-L-23、CMAP-L-24和CMAP-L-25对MCF7细胞的抑制率与CMAP-8相比,差异达到了极显著水平(Duncan-test,P0.01)。所筛选的4条多肽净电荷数为6~8,疏水度均为46%,而天然多肽CMAP-8净电荷为0,疏水度为42%。多肽活性预测结果与体外抗乳腺癌检测结果一致,共同表明了净电荷的改变对多肽抗乳腺癌活性的影响更大,而疏水度并非越大越好,应该处在合适的范围内。     

大豆多肽苦味机理及脱苦技术

大豆多肽具有多种优良的生理活性功能,具有广泛的应用价值。但其在酶解过程中产生苦味,影响其加工和应用。本文综述了大豆多肽苦味的形成受多肽疏水度、氨基酸序列及空间结构的影响和脱苦技术的理化、酶法及微生物脱苦法等。     

Antibodies that react with predetermined sites on proteins

Contrary to previous predictions, relatively short synthetic peptides that mimic part of a protein sequence are routinely capable of eliciting an antiserum that reacts with the partially mimicked protein. Peptides capable of eliciting protein-reactive serums are frequently represented in the primary sequence of a protein, can be characterized by a set of simple chemical rules, and are confined neither to immunodominant regions of intact proteins nor to the amino or carboxyl terminals. As such, synthetic peptide immunogens are valuable for eliciting reagents with predetermined specificity that can be used for basic research. In addition, some synthetic peptides are capable of mimicking regions of virus proteins and eliciting immune responses in animals that are protective against the viral agents. Such peptides may thus serve as the basis for safe, chemically defined synthetic vaccines.     

昆虫抗菌肽研究与应用

昆虫抗菌肽(AMPs)是昆虫在受到刺激或感染之后,在其血淋巴中会产生的一种抗菌类物质,具有分子量小、稳定性好、广谱抗菌、无毒副作用等特点。随着抗菌肽家族的不断扩大,其各方面的研究也日益深入,昆虫抗菌肽作为一种新型短肽以其独特的特性已成为食品、农业、医药等领域的研究热点。简要综述了昆虫抗菌肽的生物特性、作用机理及应用现状。     

水溶性黑柄炭角菌肽的体外抗氧化活性

研究水溶性黑柄炭角菌肽的体外抗氧化活性 方法通过测定水溶性黑柄炭角菌肽对邻苯三酚自 氧化产生的超氧阴离子Fenton反应产生的羟自由基DPPH自由基的清除率还原能力及抑制脂质体过氧化全面 考察水溶性黑柄炭角菌肽的体外抗氧化能力 结果水溶性黑柄炭角菌肽能明显降低邻苯三酚自氧化速率对羟自 由基有极强的清除能力对DPPH自由基清除率随浓度增加而增加其IC50 分别为10 0.49 mg/mL和16.3 g/mL 进一步研究表明黑柄炭角菌肽具有一定的还原力且与浓度呈正比例关系同时也能抑制脂质体的过氧化反应 结 论水溶性黑柄炭角菌肽在体外具有明显的抗氧化作用 关键词     

抗菌肽在农业和食品工业上的应用

抗菌肽是免疫学的研究热点,具有防效好、抗菌谱广、无污染等特点,是传统化学杀虫剂和抗生素的有力新型替代物,也可改善杀虫剂和抗生素长时间滥用导致的害虫和病原体抗性。人们也已经掌握了许多基因编码的动植物抗菌肽,并以此成功设计了新型杀虫剂和药物,许多都已生产和应用。虽然抗菌肽也有正常机体认可及应用技术等问题亟待解决,但是其在农业和食品工业中的成功应用,预示着抗菌肽的前景会很广阔。     

米糠肽的研究与应用

介绍了米糠蛋白的性质及其活性肽在降血压、阿片样拈抗活性、抗氧化、免疫调节等方面的作用,并概述了米糠蛋白及肽在食品行业的应用状况及发展前景.     

Brain peptides: what, where, and why?

Within the past decade, a large number of peptides have been described within the vertebrate central nervous system. Some of these peptides were previously known to be present in nonneural vertebrate tissues, as well as in lower species, in which they may serve as primitive elements of intercellular communication prior to the development of neuronal or endocrine systems. In vertebrates, these peptides are thought to have neurotransmitter or neuromodulatory roles and appear to be involved in the regulation of a number of homeostatic systems, although the mechanisms of their actions are still unclear.