载脂蛋白模拟肽的研究进展

载脂蛋白模拟肽是利用现代生物技术合成的与载脂蛋白功能相当而分子量更小的一类多肽.应用这类模拟肽治疗动脉粥样硬化及其相关性疾病已成为近年来心血管疾病治疗领域的研究热点.本文就载脂蛋白模拟肽最新研究进展做一综述.     

Regions of botulinum neurotoxin A light chain recognized by human anti-toxin antibodies from cervical dystonia patients immunoresistant to toxin treatment. The antigenic structure of the active toxin recognized by human antibodies

This work was aimed at determining the BoNT/A L-chain antigenic regions recognized by blocking antibodies in human antisera from cervical dystonia patients who had become immunoresistant to BoNT/A treatment. Antisera from 28 immunoresistant patients were analyzed for binding to each of 32 overlapping synthetic peptides that spanned the entire L-chain. A mixture of the antisera showed that antibodies bound to three peptides, L11 (residues 141-159), L14 (183-201) and L18 (239-257). When mapped separately, the antibodies were bound only by a limited set of peptides. No peptide bound antibodies from all the patients and amounts of antibodies bound to a given peptide varied with the patient. Peptides L11, L14 and L18 were recognized predominantly. A small but significant number of patients had antibodies to peptides L27 (365-383) and L29 (379-397). Other peptides were recognized at very low and perhaps insignificant antibody levels by a minority (15% or less) of patients or had no detectable antibody with any of the sera. In the 3-dimensional structure, antibody-binding regions L11, L14 and L18 of the L-chain occupy surface areas and did not correlate with electrostatic potential, hydrophilicity/hydrophobicity, or temperature factor. These three antigenic regions reside in close proximity to the belt of the heavy chain. The regions L11 and L18 are accessible in both the free light chain and the holotoxin forms, while L14 appears to be less accessible in the holotoxin. Antibodies against these regions could prevent delivery of the L-chain into the neurons by inhibition of the translocation.     

Stephen C. Woods: a precocious scientist

To investigate the early scientific development of Steve Woods, I reviewed his research during the first decade after he received his doctoral degree in 1970. The main parts of his research program were conditioned insulin secretion and hypoglycemia, Pavlovian conditioning of insulin secretion before a scheduled access to food, and basal insulin as a negative-feedback signal from fat mass to the brain. These topics were pursued with experimental ingenuity; the resulting publications were interesting, clear, and rhetorically effective. Although the theoretical framework for his experiments with insulin was homeostatic, by the end of the decade he suggested that classic negative-feedback homeostasis needed to be revised to include learning acquired by lifestyle. Thus, Woods functioned as a mature scientist from the beginning of his research—he was very precocious. This precocity also characterized his teaching and mentoring as recalled by two of his students during that time, Joseph Vasselli and Paul Kulkosky. The most unusual and exemplary aspect of his precocity is that the outstanding performance of his first decade was maintained during the subsequent 30 years.     

Proteomic identification of an MHC-binding peptidome from pancreas and breast cancer cell lines

Peptides bound to cell surface MHC class I molecules allow the immune system to recognize intracellular pathogens and tumor-derived peptides. Our goal was to learn what the immune system “sees” on the surfaces of tumor cells by acid-eluting peptides from HLA molecules for extended time periods. We determined how long peptides would continue to elute over time from a pancreatic tumor cell line, Panc-1, and a breast cancer cell line, MCF-7, at pH 3.0 in citrate buffer while monitoring viability. Both cell lines demonstrated greater than 90% viability after 25 min at pH 3.0. Panc-1 remained >90% intact after 45 min at pH 3.0. Acid eluted peptide sequences were identified using LC–MS/MS and searching the NCBI refseq database. The total number of peptides eluted peaked between 40 and 45 min for Panc-1, but continued to increase over time from MCF-7. A total of 131 peptides were identified from Panc-1 while 101 peptides were identified from MCF-7 elutions. Two classes of peptides were eluted: (1) 8–10 amino acid peptides fitting the HLA-binding motifs of each cell line, and (2) peptides longer than 10 amino acids containing HLA-binding motifs of each cell line. W6/32 antibody affinity purification of intact MHC molecules after papain cleavage of MHC class I from tumor cell surfaces also indicated that peptides longer than 10 amino acids bind to class I proteins. A peptide–MHC-refolding assay further substantiated the binding of longer peptides to HLA-A*0201. Our findings provide sequences and gene names of peptides presented by MHC class I molecules from common pancreas and breast cancer cell lines. We utilized a novel refolding assay to demonstrate that peptides longer than the canonical 8–10 amino acids commonly bind in MHC class I cell surface molecules.     

青霉源抗菌肽类霉肽素的体外抑菌活性研究

目的研究抗菌肽类霉肽素（AF）的体外抑菌活性。方法通过抑菌圈法和二倍稀释法检测AF的抗菌谱和对金黄色葡萄球菌的MIC;通过检测在AF中传代菌的敏感性确定细菌是否容易对AF产生抗药菌;将AF和细菌在不同温度和pH环境作用后检测抑菌活性,明确AF发挥活性的最适温度和pH值。结果AF对大部分供试细菌和抗药菌有效,对金黄色葡萄球菌的MIC为0．8mg／ml,金黄色葡萄球菌在AF中传代200代后敏感性不变。在14℃到30℃之间AF的抑菌活性随温度升高而降低,在pH3到pH10之间AF的活性随pH值升高而降低。结论AF是一种对抗性菌有效的广谱抗菌肽,而且不容易诱导细菌产生抗药性。     

黏附肽改性纯钛表面成骨细胞的早期黏附能力研究

目的 对纯钛表面钝化态氧化膜进行生物化学活化改性,探讨生物化学改性对钛表面成骨细胞黏附的影响.方法 24个纯钛试件打磨抛光后均分为4组,每组6个;纯钛组不处理,碱-热处理组行碱-热处理,溶胶涂层组行碱-热处理+溶胶涂层处理,黏附肽组行碱-热处理+溶胶涂层+黏附精氨酸-甘氨酸-天冬氨酸-丝氨酸肽(Glycine-Tyrosine-Arginine-Glycine-Asparticacid-Serine,GYRGDS)处理.使用X射线光电子能谱(X-ray photoelectron spectroscopy,XPS)、傅里叶变换红外光谱计(Fourier transform infrared spectrometer,FTIR)分析各组钛表面化学元素及功能基团组成;在各组钛试件表面接种成骨细胞,经2.05 Pa流体剪切力作用30 min、1 h、2 h,计算细胞残留率.结果 碱-热处理组钛表面富含大量活性羟基,溶胶涂层组钛表面富含大量羟氧基团.黏附肽组钛表面经XPS及FTIR分析检测到酰胺峰,显示GYRGDS肽成功固定于钛表面.流体剪切力作用30 min、1 h和2 h后黏附肽组钛表面的成骨细胞残留率(分别为93.0%、54.4%、34.4%)均高于相应时间点其他组.结论 GYRGDS肽修饰后的钛表面成骨细胞黏附稳定性均优于非GYRGDS肽修饰组.     

Evolution and phylogeny of the corticotropin-releasing factor (CRF) family of peptides: Expansion and specialization in the vertebrates

New sequence data on CRF family members from a number of genomes has led to the modification of our understanding of CRF evolution in the Metazoa. The corticotropin-releasing factor (CRF) family of peptides include four paralogous lineages in jawed vertebrates; CRF, urotensin-I/urocortin/sauvagine, urocortin 2 (Ucn2) and urocortin 3 (Ucn3). CRF and the urotensin-I/urocortin/sauvagine group represent a gene duplication from one lineage, whereas Ucns 2 and 3 are the result of a gene duplication in the other paralogous lineage. Both paralogous lineages are the result of a gene duplication from a single ancestral peptide that occurred after the divergence of the tunicates from the ancestor that led to the evolution of chordates and vertebrates. The presence of a single CRF-like peptide in tunicates and insects suggests that a single CRF-like ancestor was present before the separation of deuterostomes and protostomes. Currently there is no strong evidence that indicates that CRF-like peptides were present in metazoan taxa that evolved before this time although the structural similarity between some CRF peptides in insects, tunicates and vertebrates with the calcitonin family of peptides hints that prior to the formation of deuterostomes and protostomes the ancestral peptide possessed both CRF and calcitonin-like structural attributes. Here, we show evidences of conservation of CRF-like function dating back to early prokaryotes. This ancestral CRF–calcitonin-like peptide may have initially resulted from a horizontal gene transfer event from prokaryotes to a protistan species that later gave rise to the metazoans.     

人工合成多肽防龋疫苗HDS的研究——I多肽HDS序列合成和鉴定

目的：人工合成变形链球菌葡糖基转移酶第549～567位多肽序列HDS。方法：应用固相多肽合成仪合成变形链球菌葡糖基转移酶上549～567位氨基酸序列HDS，使用基质辅助激光解吸电离飞行时间质谱法碎片结构分析技术，对合成产物进行检测。结果：准确合成了19个氨基酸的多肽序列HDS，纯度达97％。结论：成功合成变形链球菌葡糖基转移酶多肽片断为多肽防龋疫苗研究提供了基础。     

支气管哮喘患儿血浆降钙素基因相关肽和神经肽Y水平测定及临床意义

目的 :探讨降钙素基因相关肽 ( CGRP)和神经肽 Y( NPY)在儿童支气管哮喘时的水平变化以及在哮喘发病机制中的作用。方法 :采用放射免疫法 ( RA)对 38例支气管哮喘和 2 5例正常儿童血浆 CGRP和 NPY进行了检测。结果 :支气管哮喘患儿急性期血浆CGRP及 NPY均明显高于对照组 ( P<0 .0 1 ) ,而在哮喘缓解期 CGRP和 NPY有所降低 ,但仍高于对照组 ( P<0 .0 5 )。CGRP与 NPY水平之间有轻度相关关系 ( r=0 .65 ,P<0 .0 5 )。结论 :CGRP和 NPY的水平升高参与了支气管哮喘的发病机制 ,与哮喘病情严重性有密切关系     

^99mTc—P357血栓显像诊断急性肺栓塞的初步临床研究

为评价９９ｍＴｃＰ３５７血栓显像对急性肺栓塞的诊断价值及其安全性，对７例疑有急性肺动脉血栓栓塞的患者，经静脉注射９９ｍＴｃＰ３５７，１和２小时后行肺平面及断层显像，并与９９ｍＴｃ大颗粒聚合白蛋白肺灌注显像、肺动脉造影、超高速ＣＴ、ＤＳＡ和螺旋ＣＴ对比。结果：４例急性肺栓塞中３例９９ｍＴｃＰ３５７血栓显像阳性，１例溶栓后１个月血栓显像为阴性；另外３例显像结果为阴性，临床诊断分别为慢性肺栓塞、肺血管炎和高血压。初步临床研究表明，９９ｍＴｃＰ３５７对急性肺栓塞的诊断有较大价值。