宽体金线蛭与菲牛蛭抗凝血酶活性及抗凝机制比较研究

摘 要 目的：比较宽体金线蛭和菲牛蛭抗凝血酶活性及对凝血途径的影响,为进一步揭示水蛭抗凝作用机制提供参考。方法: 采用凝血酶滴定法、发色底物法 萃取 HPLC联合法测定水蛭对凝血酶的作用;同时采用凝固法测定其活化部分凝血活酶时间（APTT）、凝血酶原时间（PT）和凝血酶时间（TT）,比较宽体金线蛭与菲牛蛭对不同凝血途径的影响。结果: 凝血酶滴定法的结果表明,不同水蛭的抗凝活性顺序依次为：菲牛蛭活体冻干品>菲牛蛭清水吊干品>>宽体金线蛭清水吊干品;发色底物法 萃取 HPLC法测定不同水蛭对凝血酶抑制作用的结果表明：不同水蛭水提取物对凝血酶的作用均表现出低浓度促进,高浓度抑制,且菲牛蛭具有强烈凝血酶抑制活性,而宽体金线蛭在加入更高剂量时才表现出抑制作用,且抑制作用较弱,菲牛蛭的抗凝血酶活性远远高于宽体金线蛭;不同水蛭样品均使APTT、PT、TT延长,但是菲牛蛭活体冻干品主要延长TT,清水吊干品主要延长APTT,而宽体金线蛭使APTT、TT延长更加显著。结论:宽体金线蛭和菲牛蛭对凝血酶及凝血途径的作用很大区别。     

基于分子生物学特异性扩增的方法鉴别菲牛蛭

目的：通过DNA条形码鉴定和建立特异性引物扩增的方法,有效区分菲牛蛭与其他水蛭品种。方法：通过聚合酶链式反应（PCR）对水蛭样品的COI序列进行扩增,利用MEGA 6.06软件通过建树法进行NJ树聚类分析,针对菲牛蛭素的编码基因序列、利用Primer Premier 5软件进行引物设计,对经设计、合成的8对引物通过PCR扩增和琼脂糖凝胶电泳实验进行筛选,并确定特异性引物的最佳退火温度。结果：通过COI序列的NJ树聚类分析可以确定20批水蛭样品中的9批菲牛蛭样品,经过Primer Premier 5软件进行引物设计共选出8对引物进行合成,通过PCR扩增和琼脂糖凝胶电泳预实验筛选出引物7、为最佳实验引物,且确定了引物7的最佳退火温度为49℃。结论：通过COI序列的DNA条形码研究,确定了样品中的菲牛蛭,通过特异性引物PCR扩增和电泳检测,有效地将菲牛蛭与其他水蛭样品进行区分,为菲牛蛭的分子生物学鉴定方法提供了参考。     

重组人粒细胞巨噬细胞集落刺激因子质量肽图分析及二硫键定位

目的 采用液相色谱-质谱联用技术绘制重组人粒细胞巨噬细胞集落刺激因子的质量肽图并鉴定二硫键位点。方法 重组人粒细胞巨噬细胞集落刺激因子原液经变性、还原、烷基化、脱盐、胰蛋白酶和V₈酶分别酶解后进行质量肽图分析;原液经变性、烷基化、脱盐、V₈酶和V₈酶结合胰蛋白酶分别酶解后进行二硫键定位鉴定。结果 胰蛋白酶酶切的质量肽图共发现14个匹配肽段,V₈酶酶切的质量肽图共发现18个匹配肽段,肽段覆盖率均为100%。经V₈酶酶切仅鉴定到1种二硫键匹配方式即Cys55-Cys97,经V₈酶结合胰蛋白酶酶切鉴定到2种二硫键匹配方式即Cys55-Cys97和Cys89-Cys122。结论 应用液相色谱-质谱联用技术进行质量肽图分析和二硫键定位可作为重组蛋白药物质量控制方法。     

基于斑马鱼模型比较宽体金线蛭和菲牛蛭对血管新生的影响

摘 要 目的：探讨及比较宽体金线蛭和菲牛蛭对Tg（kdrl:mCherry）斑马鱼的血管新生影响。方法: 将受精后 6 ~ 8 h（6 ~ 8hpf）的胚胎暴露在含不同浓度宽体金线蛭和菲牛蛭水提取物的胚胎培养液中,每24 h更换一次含药培养液。72 hpf时,在显微镜下观察发育形态和节间血管,测定48,72 hpf孵化率,72 hpf节间血管数目、心率。结果: 在抑制血管新生方面,宽体金线蛭组浓度≥30 μg· ml^-1时,菲牛蛭组浓度≥20 μg· ml^-1时,斑马鱼节间血管数目均较空白组明显减少（P<0.01）。毒性方面,在48 hpf,给药组浓度≥40 μg· ml^-1时,宽体金线蛭和菲牛蛭组斑马鱼的孵化率均较空白组明显降低（P<0.01）;在72 hpf,宽体金线蛭组斑马鱼的孵化率在100 μg·ml^-1时较空白组明显降低（P<0.01）,而菲牛蛭组斑马鱼的孵化率在80 μg· ml^-1就明显降低（P<0.01）。宽体金线蛭和菲牛蛭组斑马鱼的卵黄囊、心囊无明显水肿,脊柱未弯曲;两组心率显著降低（P<0.01）,但在正常心率范围内。结论: 宽体金线蛭和菲牛蛭都具有抗血管生成活性,且菲牛蛭的抗血管生成活性强于宽体金线蛭。两者对斑马鱼发育有一定程度的影响,但毒性不大。     

不同品种水蛭抗凝抗血栓作用的比较

目的:比较研究宽体金线蛭和菲牛蛭的体内外的抗凝、抗血栓作用。方法:采用凝血酶直接滴定法测定不同处理方法的2种水蛭体外抗凝血活性;采用胶原蛋白-肾上腺素诱导小鼠脑血栓,角叉菜胶诱导小鼠尾静脉血栓以及大鼠动-静脉旁路血栓形成的方法,观察不同处理方法的两种水蛭的抗血栓作用。采用毛细管法和剪尾法,观察不同处理方法的两种水蛭的抗凝血作用。结果:菲牛蛭鲜体和干品的体外抗凝活性远优于鲜体及干燥宽体金线蛭;鲜品菲牛蛭、干燥菲牛蛭以及经不同方法处理的宽体金线蛭均具有明显的体内抗凝抗血栓活性,其中以菲牛蛭鲜品的作用最强烈;煎煮后的菲牛蛭几乎无体内外生物活性。结论:菲牛蛭与宽体金线蛭的活性成分有很大区别,且菲牛蛭比目前广泛应用的宽体金线蛭具有更优的药效活性。     

特征肽技术用于龟甲(浙龟甲)中掺巴西龟的检查研究

目的 找出巴西龟特征肽段,建立龟甲（浙龟甲）中掺入巴西龟的专属性检查方法。方法 样品以水提法提取,胰蛋白酶酶解,利用超高效液相色谱-四级杆飞行时间质谱和数据处理软件查找巴西龟特征肽,并利用蛋白质搜库技术初步测序;利用找到的特征肽段,建立超高效液相色谱-串联四级杆质谱的多反应监测的巴西龟掺伪专属性检查方法。结果 找出巴西龟特征性肽段m/z 400.23（双电荷）,并初步测定序列,通过分析该特征肽段二级质谱图,确定了专属性检测离子对m/z 400.23（双电荷）→374.05,142.90,并建立了龟甲（浙龟甲）中掺入巴西龟的专属性检查方法。20批样品中,11批样品检出巴西龟成分。结论 该方法的专属性强,符合分析检测的方法技术要求,可用于龟甲（浙龟甲）掺入巴西龟的检查。     

僵蚕抗凝成分仿生提取液的氨基酸序列分析

目的利用高效液相色谱-质谱法（LC-MS/MS）对僵蚕胃蛋白酶提取液的有效抗凝成分进行结构分析。方法采用Hola C₁₈ (2.1mm×100 mm,2.7 μm)色谱柱, 以0.05%甲酸水溶液-0.05%甲酸乙腈溶液为流动相,梯度洗脱, LC-MS/MS正离子模式分析,初步探究抗凝活性成分的相对分子量和氨基酸组成。结果僵蚕经胃蛋白酶解得到相对分子量500~1000的活性肽,且多肽为低于10个氨基酸组成的低聚肽。结论僵蚕蛋白类组分通过酶解为活性低聚肽发挥抗凝作用,胃蛋白酶提取法更具科学性。     

广西菲牛蛭消化液中抗凝物质的分离纯化

目的从广西菲牛蛭中分离纯化抗凝物质,并对其生化性质进行测定。方法用三氯醋酸沉析、离子交换、凝胶过滤和高效液相色谱法分离纯化广西菲牛蛭消化液中的抗凝物质,用SDS-聚丙烯酰胺凝胶电泳测定其蛋白质的相对分子质量(Mr),用等电聚焦法测定蛋白质的等电点。结果从广西菲牛蛭中分离出2种抗凝物质———菲牛蛭素A(BDA)和菲牛蛭素B(BDB),BDAMr约为15 200,等电点为3.97;BDBMr为14 600,等电点为4.61。每1 000 mL菲牛蛭消化液(含抗凝活性10 ATU/mg)可分离出BDA 630μg,收率约为0.303%,比活为2 777.8 ATU/mg,活性收率约为27.8%;BDB 615μg,收率约为0.300%,比活为2 845.5 ATU/mg,活性收率约为28.4%。结论从广西菲牛蛭消化液中分离出的BDA,BDB对凝血酶具有极强的抑制作用,具有广阔的运用前景。     

广西菲牛蛭中一种纤溶酶的分离纯化

目的从广西菲牛蛭消化液中分离纯化出一种纤溶酶,并研究其生化性质。方法应用有机溶剂沉淀、DEAESepharoseCL-6B离子交换柱和SephadexG-75凝胶柱过滤的方法分离纯化出广西菲牛蛭纤溶酶,用纤维蛋白平板法测定其纤溶活力,SDS-聚丙烯酰胺凝胶电泳测定纤溶酶相对分子质量(Mr)。结果从广西菲牛蛭中分离出一种单一组分的纤溶酶,其Mr约为42×103,在普通纤维蛋白平板和加热平板上都能溶解纤维蛋白,收率为0.43%。结论此方法成功地从广西菲牛蛭中分离出一种纤溶酶,其纤溶机理是直接溶解纤维蛋白。     

长白山白眉蝮蛇血凝酶的分离纯化研究

摘 要 目的：建立一种分离纯化长白山白眉蝮蛇血凝酶的方法。方法: 先后采用分子筛层析法、离子交换色谱法、肝素 Sepharose亲和层析法从长白山白眉蝮蛇蛇毒中分离纯化得到一种具有有凝血活性的酶成分,并采用SDS-Page法、RP-HPLC法测定其纯度,凝胶电泳法(SDS-Page)考察其对牛纤维蛋白原的作用方式、高效空间排阻色谱法（HPSEC）测定其相对分子质量,等电聚焦电泳分析法（IEF）测定其等电点,Lowry法测定其蛋白浓度。结果: 从长白山白眉蝮蛇蛇毒中分离纯化了一种凝血酶成分,SDS-Page显示为一条带,HPLC得到单一的色谱峰,该酶只作用于纤维蛋白原的α链,其相对分子质量为32.2 kD,等电点为5.21,此酶具有体外凝血活性。结论:该方法可用于长白山白眉蝮蛇血凝酶的分离纯化。     

Patent Evaluation: Antimicrobial Peptides

Summary

Novelty: New peptides, which are said to have good antimicrobial activity, are disclosed.

Biology: The antimicrobial activity of these peptides was determined against E. coli proliferation, Gram-negative and Gram-positive microorganisms, and fungal strains. The results demonstrate an antimicrobial effect at a concentration of at least 5 ppm.

Chemistry: The peptide isolated from an enzymatic hydrolysate of bovine LF was determined together with various other effective peptides.     

方格星虫多肽的结构分析及体外抗氧化活性

目的 以方格星虫为原料,酶解制备水溶性多肽并考察其抗氧化活性,探究其结构-活性关系。方法 利用5种蛋白酶酶解新鲜方格星虫,并结合超滤方法得到高分子量(>50kDa)、中分子量(5～50 kDa)和低分子量(＜5kDa)的酶解肽段;利用氨基酸自动分析仪测定方格星虫酶解肽的氨基酸组成。综合考察多肽对1,1-二苯基-2-苦基肼(DPPH.)自由基、羟基自由(.OH)、超氧阴离子自由基( O-2.)的清除能力以及还原力效果,评价方格星虫多肽抗氧化活性;利用高效液相色谱-串联质谱方法鉴定小分子肽的氨基酸组成和序列结构。结果 胰蛋白酶水解方格星虫4h得到的酶解液蛋白含量最高,并在酶解液中检测确定了17种氨基酸,其中精氨酸含量最高13.65%。高中低三组肽段中,低分子量肽段的抗氧化活性优于其他：对DPPH 自由基和羟自由基清除能力大小顺序为低分子量>高分子量>中分子量、对超氧阴离子清除能力大小顺序为低分子量>高分子量≈ 中分子量、还原能力强弱顺序为高分子量>低分子量 > 中分子量。经高效液相色谱-串联质谱联鉴定了GFAGDDAPR、GLGGLSPEK 、LDLAGR和VTKEIPR 4个肽段。结论 低分子量的方格星虫酶解多肽具有较好的抗氧化活性,有潜力用作生物医药或化妆品工业的原料。     

The Effect of β-Turn Structure on the Permeation of Peptides Across Monolayers of Bovine Brain Microvessel Endothelial Cells

Purpose. To investigate the effects of the -turn structure of a peptide on its permeation via the paracellular and transcellular routes across cultured bovine brain microvessel endothelial cell (BBMEC) monolayers, an in vitro model of the blood-brain barrier (BBB). Methods. The effective permeability coefficients (P_eff) of the model peptides were determined across BBMEC monolayers. The dimensions of the aqueous pores in the tight junctions (TJs) of the BBMEC monolayers were determined using a series of hydrophilic permeants. This value and the molecular radius of each peptide were used to calculate the theoretical paracellular (P_P ^*) and transcellular (P_T ^*) permeability coefficients for each peptide. Results. A comparison of the theoretical P_P ^* values with the observed P_eff values was made for a series of model peptides. For the most hydrophobic peptides (Ac-PheProXaaIle-NH₂ and Ac-PheProXaaIleVal-NH₂; Xaa = Gly, Ile), it was concluded that the Gly-containing peptide of each pair more readily permeates BBMEC monolayers via the transcellular pathway than the Ile-containing analog. In addition, the Gly-containing peptides, which exhibit more -turn structure, were shown to be more lipophilic than the Ile-containing peptides as estimated by the log of their l-octanol:HBSS partition coefficients (log P_o/w). However, the three hydrophilic peptide pairs (Ac-TyrProXaaAspVal-NH₂, Ac-TyrProXaaAsnVal-NH₂, and Ac-TyrProXaaIleVal-NH₂; Xaa = Gly, Ile) were found to permeate BBMEC monolayers predominantly via the paracellular pathway. No differences were observed in the P_eff values of the hydrophilic peptides having higher -turn structures as compared to the peptides lacking these structural features. In addition, the Ile-containing peptides exhibited significantly higher log P_o/w values than the Gly-containing hydrophilic peptides. Conclusions. Hydrophobic peptides that exhibit significant -turn structure in solution are more lipophilic as measured by log P_o/w, and more readily permeate BBMEC monolayers via the transcellular route than hydrophobic peptides that lack this type of solution structure. Similar secondary structural features in hydrophilic peptides do not appear to sufficiently alter the physicochemical properties of the peptides so as to alter their paracellular flux through BBMEC monolayers.     

Proteome of monocled cobra (Naja kaouthia) venom and potent anti breast cancer peptide from trypsin hydrolyzate of the venom protein

Anticancer peptide is one of the target in the development of new anticancer drug. Bioactive peptide can be originated from isolated free peptide or produced by hydrolysis of protein. Protein is the main component of Naja kaouthia venom, and due to the toxicity of the venom, it can be assessed as the source of anticancer peptides. This study aims to characterize the venom protein and to identify peptides from the snake venom of N. kaouthia as anticancer. Proteome analysis was employed trypsin hydrolysis of N. kaouthia venom protein completed with HRMS analysis protein database query. Preparative tryptic hydrolysis of the protein followed by reverse-phased fractionation and anti breast cancer activity testing were performed to identify the potent anticancer from the hydrolysate. Proteomic analysis by high-resolution mass spectrometry revealed that there are 20 enzymatic and non-enzymatic proteins in N. kaouthia venom. The 25% methanol peptide fraction had the most active anticancer activity against MCF-7 breast cancer cells and showed promising selectivity (selectivity index = 12.87). Amino acid sequences of eight peptides were identified as potentially providing anticancer compounds. Molecular docking analysis showed that WWSDHR and IWDTIEK peptides gave specific interactions and better binding affinity energy with values of −9.3 kcal/mol and −8.4 kcal/mol, respectively. This study revealed peptides from the snake venom of N. kaouthia became a potent source of new anticancer agents.     

HAZ,a novel peptide with broad-spectrum antibacterial activity

ObjectiveThe growing microbial resistance to antibiotics is a global public concern, which creates serious needs for newer antimicrobial agents. Antimicrobial peptides (AMPs) are increasingly exploited in drug development as therapeutic candidates. Here, we aimed to design and characterize a novel peptide with broad spectrum antimicrobial activity.MethodsHybridization and sequence modification approaches were used to design the novel peptide, named HAZ, aiming at optimizing the physicochemical parameters involved in antimicrobial activity. Peptide activities were assessed alone or combined with different selected antibiotics against various sensitive and drug-resistant bacterial strains. In addition, the hemolysis and the cytotoxic activities of HAZ peptide were evaluated on human red blood cells and epithelial adenocarcinoma cells (A549), respectively.ResultsHAZ peptide was sequentially modified to result in favored physicochemical parameters (helicity 95.24 %, hydrophobic ratio 47 %, and net charge of 8 + ). Functional assessment of HAZ revealed significant antimicrobial activity, with MIC values of 15 – 20 µM against tested bacterial strains. It also exhibited biofilm eradication activity at slightly higher concentrations. HAZ-antibiotics combinations exhibited a synergistic action mode that led to dramatic decrease in the MIC values for both HAZ peptide and the antibiotic. Such efficacy was accompanied with minimal hemolytic toxicity on human erythrocytes. Importantly, HAZ displayed promising anticancer activity against human lung cancer cells.ConclusionRationally-designed antimicrobial peptides offer promising alternatives to the current antibiotics for management of infectious diseases. HAZ peptide is a broad-spectrum AMP, and a promising candidate for antimicrobial and anticancer drug development.     

Activities of ACTH-potentiating substances isolated from rat serum on steroidogenesis in isolated rat adrenal cells

Peptides that potentiate the response of adrenal cells to ACTH1-24 were isolated from rat serum. ACTH-potentiating activity was found in fractions of 9,000-40,000 in molecular weight (APS-Fr) and of smaller molecular weight (SM-Fr) on Sephadex G-100 gel filtration of the serum extract. The peptides were isolated from APS-Fr by preparative acid polyacrylamide gel electrophoresis and named d1, d, d2, e, f and g. Their molecular weights, estimated by Sephadex G-75 gel filtration, were 41,000, 33,000, 24,000, 17,500, 17,500 and 16,000, respectively. All of these peptides were glycopeptides. The isoelectric point of peptide d was 8.45 and some of the others, such as f and g, were more basic. Sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis revealed that these peptides were decomposed into various fragments. ACTH-potentiating activity was highest in peptide d1 and lowest in peptide e. The maximum activity of peptide d was observed at 3 X 10(-8) M when steroidogenesis was induced by 9 X 10(-12) M ACTH1-24. While these peptides did not show any ACTH-like activity at any stage of isolation, the fractions of these peptides eluted from a Sephadex G-75 column showed more or less ACTH-like activity. These peptides therefore seemed to possess latent ACTH-like activity. The molecular weight of SM-Fr was smaller than ACTH1-24. The ACTH-potentiating activity of SM-Fr was low, and SM-Fr did not show any ACTH-like activity. SM-Fr therefore seems to be the smallest structure which has ACTH-potentiating activity. The similarity of these peptides to proopiomelanocortin-related substances was discussed.     

Optimization of phage heptapeptide library-screening process for developing inhibitors of the isocitrate lyase homologue from Mycobacterium tuberculosis

The aims of this study were to screen peptide inhibitors specific for isocitrate lyase (ICL) using a phage peptide library and computer molecular docking and to explore the relevant mechanisms. Using ICL as a target, the phage peptide library was screened to obtain peptides with specific binding affinity. Based on the three-dimensional crystal structure of ICL(pdb:1F8I), the obtained polypeptides were docked to the 1F8I using the computer-simulated molecular docking technique. The successfully docked polypeptides were synthesized using the Fmoc solid-phase synthesis method, and the ICL inhibition rate of these peptides was measured. Finally, the possible mechanism underlying the inhibition was explored by Binding Site Analysis. A total of 29 heptapeptides were obtained through screening the phage peptide library. We found that 12 out of the 29 peptides were successfully docked to the 1F8I, and all 12 peptides could obviously inhibit the ICL activity, of which three heptapeptides showed an inhibiting (extent of inhibition over 50 %), IC50 value of 126 μM. Structural analysis revealed that the ICL tetramer has a large cavity in the center, and the polypeptides bind to ICL at amino acid residue 119’s GLN of the ICL monomer. We successfully obtained peptide inhibitors specific for ICL, and analyzed the mechanism underlying the interaction between the peptides and ICL. Our study provides scientific evidence for the development of antituberculosis peptide drugs targeting ICL.     

Evaluation of basic amphipathic peptides for cellular delivery of antisense peptide nucleic acids

Cellular permeation peptides have been used successfully for the delivery of a variety of cargoes across cellular membranes, including large hydrophilic biomolecules such as proteins, oligonucleotides, or plasmid DNA. For the present work, a series of short amphipathic peptides was designed to elucidate the structural requirements for efficient and nontoxic delivery of peptide nucleic acids (PNAs). On the basis of an idealized alpha-helical structure, the helical parameters were modulated systematically to yield peptides within a certain range of hydrophobicity and amphipathicity. The corresponding PNA conjugates were synthesized and characterized in terms of secondary structure, enzymatic stability, and antisense activity. The study revealed correlations between the physicochemical and biophysical properties of the conjugates and their biological activity and led to the development of potent peptide vectors for the cellular delivery of antisense PNAs. Two representative compounds were radiolabeled and evaluated for their biodistribution in healthy mice.     

Structural properties of bioactive peptides with α‐glucosidase inhibitory activity

Bioactive peptides are emerging as promising class of drugs that could serve as α‐glucosidase inhibitors for the treatment of type 2 diabetes. This article identifies structural and physicochemical requirements for the design of therapeutically relevant α‐glucosidase inhibitory peptides. So far, a total of 43 fully sequenced α‐glucosidase inhibitory peptides have been reported and 13 of them had IC₅₀ values several folds lower than acarbose. Analysis of the peptides indicates that the most potent peptides are tri‐ to hexapeptides with amino acids containing a hydroxyl or basic side chain at the N‐terminal. The presence of proline within the chain and alanine or methionine at the C‐terminal appears to be relevant for high activity. Hydrophobicity and isoelectric points are less important variables for α‐glucosidase inhibition whilst a net charge of 0 or +1 was predicted for the highly active peptides. In silico simulated gastrointestinal digestion revealed that the high and moderately active peptides, including the most potent peptide (STYV), were gastrointestinally unstable, except SQSPA. Molecular docking of SQSPA, STYV, and STY (digestion fragment of STYV) with α‐glucosidase suggested that their hydrogen bonding interactions and binding energies were comparable with acarbose. The identified criteria will facilitate the design of new peptide‐derived α‐glucosidase inhibitors.