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以屠宰场收集的新鲜、健康、雌性绵羊生殖器官为原材料．采用乙酸浸提、透析、Sephadex G-50凝胶过滤层析和反相高效液相色谱(RP-HPLC)等方法分离纯化绵羊生殖道抗菌肽．以G+、G-和真菌为抗菌活性检测指示菌株,利用薄层琼脂糖孔穴扩散法、微量肉汤稀释法进行抗菌活性检测．对分离纯化所得纯品进行分子质量质谱测定、纯度鉴定、N端测序,并对其性质进行研究．结果表明：分离纯化所得两个绵羊生殖道抗菌肽分子质量分别为4820.47 u和4012.5 u,N端部分氨基 酸序列分别为AYVLDEPKP和YDSGA．对G+细菌(S. aureus ATCC2592、Streptococcu ATCC55121)、G-细菌(E． coli ATCC25922)、真菌(C． albicans ATCC2002)均具有良好的抑菌活性．对家兔红细胞无溶血活性,对人血液凝固无影响．目前未见有从绵羊生殖道分离纯化得到抗菌肽的报道,并且这一研究结果进一步证实抗菌肽在多种动物生殖道天然免疫防御方面起着重要作用． 相似文献
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以我国主要经济海产品中国对虾（Penus chinensis）为研究对象,通过Sephadex G-50、RP-HPLC等技术分离纯化到PC-Ⅲ系列中国对虾天然抗菌肽。经初步鉴定,该系列抗菌肽对革兰氏阴性和革兰氏阳性菌都表现出程度不一的抑菌活性,且不同程度地影响小白鼠离体回肠肌收缩,但无丝氨酸蛋白酶抑制剂活性。用MALDI-TOF质谱对样品进行分析,检测到分子量分别为1071Da和1311Da的两种抗菌肽。这些抗菌肽对对虾抵御微生物的侵袭具有重要的作用。 相似文献
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鸣叫对无尾两栖类动物的生存与繁殖起重要作用。蛙类的鸣叫行为受到环境因素影响表现出一定的节律性。2016年8和9月,采用录音机和指向性话筒,在野外录制了57只沼水蛙（Hylarana guentheri）的鸣声并对其鸣声特征进行分析;通过悬挂录音笔和自动温湿度记录仪研究了沼水蛙鸣叫节律（17 d）及其与环境温度、相对湿度的关系。结果显示,沼水蛙的鸣声由1 ~ 4个音节组成,不同类型鸣声间的音节主频、音节时长存在显著差异（P < 0.05）。该物种全天具有鸣叫行为,13:00 ~ 14:00时为鸣叫高峰期。白天单音节鸣声、双音节鸣声、三音节鸣声、总鸣声和总音节的数量较夜晚显著增加（P < 0.01）。鸣声数量和音节数量均与环境温度呈正相关（P < 0.01）。结果表明,沼水蛙通过改变音节数量、音节主频和音节时长改变鸣叫策略。沼水蛙的鸣叫行为具有昼夜节律性且受环境温度的影响。 相似文献
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【背景】食品腐败的主要原因是食源性致病菌的污染。乳酸菌产生抗菌肽能够有效抑制食源性致病菌的生长。【目的】对一株具有广谱抑菌能力的植物乳植杆菌（Lactiplantibacillus plantarum）J50展开研究,分离纯化其产生的抑菌物质并开展其基因组学分析。【方法】通过多种酶处理判断抑菌物质种类,通过有机溶剂萃取、凝胶过滤层析和半制备高效液相色谱对其分离纯化,使用液质联用表征,人工合成后测定其稳定性和最低抑制浓度,并对菌株开展基因组学分析。【结果】通过酶敏感性试验判断其产生的抑菌有效物质为抗菌肽,分离纯化得到抗菌肽纯品,表征出肽段序列为：SGAGY （N→C）,相对分子质量为453.44 Da。其在pH≤5.5时能保持有效抑菌能力,具有较强的热稳定性和紫外线照射稳定性,对实验的G+和G–食源性致病菌的最低抑制浓度在0.7-1.6g/L。基因组学分析显示抗菌肽SGAGY是非核糖体肽,并且菌株J50具有双肽细菌素plantaricin EF合成相关基因。【结论】菌株J50至少能够产生2种高效抗菌肽,抑菌谱系较广,具有应用于食品工业的潜在价值。 相似文献
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经硫酸铵沉淀、超滤、阳离子交换分离和反相快速蛋白质液相色谱（FPLC）分析,得到了两种新的蚯蚓抗菌肽F-1与F-2,经电喷雾离子源质谱（ESI-MS）测定,其相对分子质量为535.27和519.27.串联质谱（MS/MS）数据表明F-1的肽序列为Ac-Ala-Met-Val-Ser-Ser,F-2的肽序列为Ac-Ala-Met-Val-Gly-Thr.最小抑菌浓度（MIC）实验表明,F-1与F-2对鹑鸡肠球菌(Enterococcus gallinarum)、绿脓杆菌(Pseudomonas pyocyanea)、鲍氏不动杆菌(Acinetobacter baumanii)、土生克雷伯氏菌（Klebsiella terrigena）的最小抑菌浓度分别为11.4 mg/L和12.85 mg/L,对粪肠球菌(Enterococcus faecalis)的最小抑菌浓度分别为22.8 mg/L和25.68 mg/L.对真菌白色念株菌（Candida albicans）没有表现为完全的抑制作用. 相似文献
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中国林蛙和中华蟾蜍皮肤抗菌肽的分离纯化及其抗菌活性 总被引：1，自引：0，他引：1
分别以中国林蛙长白山亚种Rana chensinensis changbaishansis和中华蟾蜍Bufo gargarizans的鲜皮为原料,通过酸化乙醇法提取抗菌肽粗提液,再经葡聚糖凝胶层析进一步分离纯化获得抗菌肽纯品,采用滤纸片法进行抑菌活性研究.结果 表明,经Sephadex G-50和Sephadex G-100分离纯化后获得3种多肽,中国林蛙与中华蟾蜍皮肤中的活性多肽对革兰氏阴性和革兰氏阳性细菌都具有一定的抗菌作用,其中多肽Ⅲ具有最佳的抑菌效果.抗菌肽相对含量比较的结果表明,蟾蜍皮肤中抗菌活性肽的含量较高,是理想的抗菌肽提出和纯化的源材料. 相似文献
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九香虫抗菌肽CcAMP1的分离纯化和抗菌活性检测 总被引：1，自引：0，他引：1
【目的】从药用昆虫九香虫 Coridius chinensis 中分离纯化抗菌肽,为进一步开发九香虫抗菌肽资源及深入挖掘九香虫的药用功能奠定基础。【方法】用大肠杆菌Escherichia coli 和金黄色葡萄球菌 Staphylococcus aureus 混合物作诱导源刺激九香虫产生抗菌肽,对血淋巴进行提取、凝胶过滤层析、固相萃取及反相色谱纯化,活性组分经质谱测定。对分离得到的这种抗菌肽进行人工合成,并进行抗菌活性检测。【结果】本研究获得一种九香虫抗菌肽CcAMP1,由17个氨基酸残基组成,分子量为1 997.37 u,带1个正电荷,表面有5个疏水氨基酸。对人工合成的CcAMP1进行抗菌活性检测表明,该抗菌肽与九香虫血淋巴一样对金黄色葡萄球菌等革兰氏阳性菌和大肠杆菌等革兰氏阴性菌都有较好的抗菌活性,且对革兰氏阴性菌的抗菌活性更强。【结论】从九香虫中分离得到具有较强抗菌活性的阳离子抗菌肽CcAMP1,有较大的开发利用价值。 相似文献
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枯草芽孢杆菌JA分泌物中具有抑菌作用的粗提液通过DEAESepharose FF、SOURCE 15 PHE、Sephacry1 S200HR和反相HPLC多步柱层析分离纯化后,获得3种对水稻纹枯和小麦赤霉病菌均有抑菌作用的抗菌肽AFP1、AFP2和AFP3。MALDITOF质谱法测得其分子量分别为1462.645D、1476.390D和1490.530D。氨基酸组成分析结果表明,AFP1和AFP3由苏氨酸、异亮氨酸、酪氨酸、脯氨酸等多种氨基酸组成。目标产物热稳定性好、对蛋白酶有一定的耐受性,推断很可能是低分子量的环状脂肽。 相似文献
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We have investigated the effects of charge and lipophilicity on the antibacterial activity of an undecapeptide (FKCRRWQWRMK) derived from the sequence of bovine lactoferricin. We prepared ten analogues that were modified by the incorporation of Ala, Tyr, Trp, Met and Arg residues, which are amino acids known to be important for the antibacterial activity of longer derivatives of lactoferricins. All undecapeptides contained the native Trp residues in positions 6 and 8, and the Arg residues in positions 5 and 9. Generally, the Gram-positive bacterium Staphylococcus aureus was more susceptible to these undecapeptides than the Gram-negative bacteria, and a higher antibacterial activity was observed against Escherichia coli than against Pseudomonas aeruginosa. The only exception was the peptide Undeca 9 (RRWYRWAWRMR-NH2), which was almost equally active against all three test strains, displaying minimal inhibitory concentrations of 10 microg/ml (5.8 microM), 7.5 microg/ml (4.4 microM) and 5 microg/ml (2.9 microM) against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus, respectively. The peptides Undeca 6 (YRAWRWAWRWR-NH2) and Undeca 7 (YRMWRWAWRWR-NH2) were the two most active undecapeptides against Staphylococcus aureus, both displaying a minimal inhibitory concentration of 2.5 microg/ml (1.5 microM). The study showed that a level was reached in which undecapeptides having a net charge above +4 and containing three or four Trp residues all displayed a high antibacterial activity. All undecapeptides prepared were essentially non-haemolytic, but undecapeptides containing more than three Trp residues displayed 50% haemolysis of human red blood cells at concentrations above 400 microg/ml (>230 microM). 相似文献
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We report on structurally modified dodecapeptide amides (KYKLFKKILKFL‐NH2) and two analogs of a hexapeptide amide (WRWYCR‐NH2) with antibacterial activity against the Gram negative pathogens Pseudomonas syringae pv. actinidiae (Psa) and Erwinia amylovora (Ea). Dodecapeptide minimal inhibitory concentrations (MICs) ranged from 3.2 to 15.4 µM, with the unmodified peptide being the most potent against both pathogens. The unmodified dodecapeptide also had 32–58% α‐helicity in membrane mimetic environments (50% v/v trifluoroethanol and 30 mM SDS micelles). Structural modifications which included branching, acylation, and conjugation with 5‐nitro‐2‐furaldehyde (NFA) proved detrimental to both antimicrobial activity and α‐helicity. Scanning electron microscopy (SEM) revealed distinct morphological changes to bacterial cells treated with the different peptides, leading to blistering of the membrane and cell lysis. MICs of the hexapeptide amide were 3.9–7.7 µM against both pathogens. The hexapeptide acid did not show anti‐bacterial activity against either pathogen. However, the NFA conjugated hexapeptide acid was more active than the parent peptide or NFA alone with MICs of 1.6–3.2 µM against the pathogens. SEM analysis revealed shriveling and collapse of bacterial cells treated with the hexapeptide, whereas shortening and compactness on exposure to streptomycin. A colorimetric assay demonstrated that the dodecapeptides were likely to act by targeting the bacterial membrane, whereas the hexapeptides, streptomycin, and NFA were not, thereby supporting the morphological changes observed during SEM. To the best of our knowledge, this appears to be the first report of antimicrobial peptide activity against Psa, a pathogen that is currently devastating the kiwifruit industry internationally. © 2013 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 102: 88–96, 2014. 相似文献
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A series of mannuronic acid (M-block) and guluronic acid (G-block) fractions (M1–M5 and G1–G5) with different molecular weights were obtained by lyase depolymerization of alginate and evaluated for in vitro antibacterial activity against 19 bacterial strains. The antibacterial data revealed that both types of fractions generally showed activity against certain tested bacteria, whereas M-block fractions showed broader spectra and more potent inhibition than G-block fractions. Among these fractions, M3 (molecular weight 4.235 kDa) exhibited the broadest spectrum of inhibition and high inhibitory activity against Escherichia coli (minimal inhibitory concentration, MIC = 0.312 μg mL−1), Salmonella paratyphi B (MIC = 0.225 μg mL−1), Staphylococcus aureus (MIC = 0.016 μg mL−1) and Bacillus subtilis (MIC = 0.325 μg mL−1). 相似文献
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Highly antimicrobial active arginine- and tryptophan-rich peptides were synthesized ranging in size from 11 to five amino acid residues in order to elucidate the main structural requirement for such short antimicrobial peptides. The amino acid sequences of the peptides were based on previous studies of longer bovine and murine lactoferricin derivatives. Most of the peptides showed strong inhibitory action against the Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa, and the Gram-positive bacterium Staphylococcus aureus. For the most active derivatives, the minimal inhibitory concentration values observed for the Gram-negative bacteria were 5 microg/ml (3.5 microM), whereas it was 2.5 microg/ml (1.5 microM) for the Gram-positive bacterium. It was essential for the antimicrobial activity that the peptides contained a minimum of three tryptophan and three arginine residues, and carried a free N-terminal amino group and an amidated C-terminal end. Furthermore, a minimum sequence size of seven amino acid residues was required for a high antimicrobial activity against Pseudomonas aeruginosa. The insertion of additional arginine and tryptophan residues into the peptides resulted only in small variations in the antimicrobial activity, whereas replacement of a tryptophan residue with tyrosine in the hepta- and hexapeptides resulted in reduced antimicrobial activity, especially against the Gram-negative bacteria. The peptides were non-haemolytic, making them highly potent as prospective antibiotic agents. 相似文献
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AIMS: The objective of this study was to evaluate the effectiveness of antibiotics and antimicrobial peptides against 10 strains of Xylella fastidiosa. METHODS AND RESULTS: The minimal inhibitory concentration (MIC) of 12 antibiotics and 18 antimicrobial peptides were determined by agar dilution tests and growth inhibition assays. Antibiotics with the lowest MIC for X. fastidiosa strains were gentamicin, tetracycline, ampicillin, kanamycin, and novobiocin, chloramphenicol, and rifampin. Plate growth inhibition assays showed that four of the antimicrobial peptides (Magainin 2, Indolicidin, PGQ, and Dermaseptin) were toxic to all X. fastidiosa strains. CONCLUSION: All X. fastidiosa strains were sensitive to several groups of antibiotics, and minor differences in sensitivity to several antimicrobial peptides were observed among strains. SIGNIFICANCE AND IMPACT OF THE STUDY: This study shows that antibiotics and antimicrobial peptides have some activity against the pathogen, X. fastidiosa and may have application in protecting plants from developing Pierce's disease. 相似文献
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The binding, conformation and orientation of a hydrophilic vector peptide penetratin in lipid membranes and its state of self-association in solution were examined using circular dichroism (CD), analytical ultracentrifugation and fluorescence spectroscopy. In aqueous solution, penetratin exhibited a low helicity and sedimented as a monomer in the concentration range approximately 50-500 microM. The partitioning of penetratin into phospholipid vesicles was determined using tryptophan fluorescence anisotropy titrations. The apparent penetratin affinity for 20% phosphatidylserine/80% egg phosphatidylcholine vesicles was inversely related to the total peptide concentration implying repulsive peptide-peptide interactions on the lipid surface. The circular dichroism spectra of the peptide when bound to unaligned 20% phosphatidylserine/80% egg phosphatidylcholine vesicles and aligned hydrated phospholipid multilayers were attributed to the presence of both alpha-helical and beta-turn structures. The orientation of the secondary structural elements was determined using oriented circular dichroism spectroscopy. From the known circular dichroism tensor components of the alpha-helix, it can be concluded that the orientation of the helical structures is predominantly perpendicular to the membrane surface, while that of the beta-type carbonyls is parallel to the membrane surface. On the basis of our observations, we propose a novel model for penetratin translocation. 相似文献