细菌对抗菌肽的耐药性

抗微生物肽(Antimicrobial peptides)又称抗菌肽,是广泛存在于生物体内的一种具有抗微生物活性的小分子肽类.因其独特的抑菌和杀菌机制,抗菌肽被认为是当今最具有潜力的抗生素替代品,在医药卫生、水产养殖以及农业等领域具有重大的应用前景.然而,近年发现细菌对抗菌肽会产生耐药性,本文就细菌对抗菌肽耐药性研究进展作一综述.     

野生蚕抗菌肽对癌细胞的杀伤作用及其超微结构的研究

目的从野蚕蛹血淋巴中分离纯化抗菌肽,并研究野蚕抗菌肽对体外培养癌细胞的杀伤作用及超微结构的影响。方法采用MTT法检测野蚕抗菌肽对癌细胞的杀伤作用,并用透射电镜观察野生蚕抗菌肽对癌细胞超微结构的影响。结果野蚕抗菌肽对体外培养的A549、HepG2、SW620、HME1四株癌细胞具有较强的杀伤作用,而对HNE1鼻咽癌细胞和MCF-7乳腺癌细胞杀伤作用较弱,透射电镜观察发现野蚕抗菌肽处理癌细胞后其细胞表面微绒毛减少、细胞膜破损,线粒体肿胀并形成空泡,核被膜消失、核浓缩聚集靠边呈块状或新月状凋亡小体。结论野蚕抗菌肽可有效地杀伤人体不同系统的癌细胞,并诱导HepG2癌细胞凋亡。     

昆虫抗菌肽的研究和应用

昆虫抗菌肽是昆虫血淋巴中产生的一类小分子肽 ,它具有相对分子质量小、热稳定、水溶性好、强碱性、抗菌谱广的特点 ,被认为是从细菌到高等哺乳动物普遍存在的一类防御性多肽 ,称之为“第二防御体系”。抗菌肽不仅抗菌谱广 ,而且可以抑杀某些真菌、病毒及原虫 ,并对多种癌细胞及动物实体瘤有明显的杀伤作用 ,而不破坏正常细胞。近年来 ,对昆虫抗菌肽的研究已成为一个迅速发展的新领域 ,越来越引起人们的关注和重视。本研究结合近年来新发现的昆虫抗菌肽 ,就其结构、类型、抗菌机制及应用前景等方面作一综述。1　昆虫抗菌肽的类型　　迄今为…     

家蝇幼虫抗菌肽对肿瘤细胞的作用效果观察

目的研究家蝇幼虫抗菌肽对肿瘤细胞的作用效果。方法针刺感染大肠杆菌诱导家蝇幼虫产生抗菌肽,经研磨、离心、层析等步骤提取其抗菌肽,所提取的抗菌肽作用于肿瘤细胞K562、Daudi、109及T24,以流式细胞仪检测其作用效果。结果抗菌肽对4种肿瘤细胞的有效杀伤力M1均在85%以上。结论家蝇幼虫抗菌肽可作为潜在的抗肿瘤药物开发。     

家蝇幼虫抗弓形虫抗菌肽分离纯化

目的 从家蝇幼虫血淋巴中分离纯化具有抗弓形虫作用的抗菌肽.方法 通过损伤加感染的方法诱导家蝇幼虫大量表达抗菌肽,然后经过研磨、离心和层析等过程,将家蝇幼虫抗菌肽进行分离纯化,采用四甲基偶氮噻唑蓝(MTT)比色法和血细胞计数法筛选对弓形虫速殖子有抑制作用的抗菌肽.结果 经Resource S阳离子柱和Superdex G75凝胶柱层析后,筛选出2种对弓形虫速殖子有杀伤作用的抗菌肽.结论 家蝇幼虫血淋巴中存在抗弓形虫作用的抗菌肽,而且不止一种,但其效果有所不同.     

家蝇成虫抗菌肽对4种肿瘤细胞的作用观察

目的观察家蝇成虫抗菌肽对肿瘤细胞的作用效果。方法针刺感染大肠埃希菌诱导家蝇成虫产生抗菌肽,经研磨、离心、层析等步骤提取其抗菌肽,将其作用于肿瘤细胞109、K562、Daudi及T24,以流式细胞仪检测其作用效果。结果该抗菌肽对4种肿瘤细胞的有效杀伤力M1均在85%以上。结论家蝇成虫抗菌肽可作为潜在的抗肿瘤药物开发。     

抗菌肽的分子生物学研究进展

抗菌肽是具有广谱杀菌、抑病毒、抑杀肿瘤细胞等作用的一类膜活性多肽,广泛存在于从细菌到哺乳动物的生物界。本文就抗菌肽在天然免疫中的地位、抗菌作用机制、抗肿瘤作用机制等研究进展进行综述。     

昆虫抗菌肽对人淋巴瘤细胞杀伤作用及筛选

目的 筛选对人淋巴瘤细胞Daudi有抑制或杀伤作用的昆虫抗菌肽.方法 针刺感染大肠埃希菌以诱导昆虫(家蝇幼虫、成虫、蛹)产生抗菌肽,再经研磨、离心、层析等步骤提取其血淋巴中抗菌肽.将所提取的抗菌肽作用于肿瘤细胞Daudi,以流式细胞仪检测其作用效果.结果 3种抗菌肽对肿瘤细胞Daudi均有杀伤力,家蝇成虫的荧光吸收率为97.86%,幼虫为85.45%.以家蝇成虫的效果更为明显.结论 家蝇成虫抗菌肽可作为潜在的抗人淋巴肿瘤药物开发.     

家蝇蛹抗弓形虫抗菌肽的分离纯化

目的从家蝇蛹血淋巴中分离纯化具有抗弓形虫作用的抗菌肽。方法通过损伤加感染的方法诱导家蝇蛹大量表达抗菌肽，然后经过研磨、离心和AKTA^TM purifier层析等步骤，将家蝇蛹抗菌肽进行分离纯化，采用血细胞计数法和MTT比色法筛选对弓形虫速殖子有抑制作用的抗菌肽。结果经ResourceS阳离子柱层析，测定280m处紫外吸收值，在保留体积为9．4ml处出现1个紫外吸收峰，经检测对弓形虫速殖子有杀伤作用，再将其用于Superdex G75凝胶柱层析后，测定280m处紫外吸收值，出现6个紫外吸收峰，发现第6个峰具有抗弓形虫作用。结论家蝇蛹血淋巴中存在抗弓形虫作用的抗菌肽。     

抗菌肽的应用前景

通过对抗菌肽的介绍,阐述了有关抗菌肽的应用前景,为抗生素的筛选提出了可能的研究方向。     

食品用防腐剂防腐效果测定和评价程序研究

目的建立食品防腐剂防腐效果评价程序和判定标准。方法以山梨酸为实验用模式防腐剂,以细菌(金黄色葡萄球菌、大肠杆菌、肠炎沙门菌)、酵母(白色假丝酵母)、丝状真菌(黑曲霉、黄曲霉、白地霉、岛青霉和圆弧青霉)为模式微生物,将一定量(102～105cfu/ml)的微生物与一定浓度(0.25～2g/L)的防腐剂溶液混合后,间隔一定时间(3、6、24和48h)检测微生物增减的数量,依次来判断防腐剂的防腐效能。结果山梨酸无论是对细菌还是真菌均有较强的抑制作用,且随着与受试微生物作用时间的延长和防腐剂浓度的增加抑菌作用越来越强。完全抑制革兰阴性细菌所需的山梨酸浓度及作用时间高/长于革兰阳性细菌;完全抑制细菌所需的山梨酸浓度和作用时间低/短于真菌,因此革兰阳性细菌比革兰阴性细菌对山梨酸敏感,细菌比真菌对山梨酸敏感。结论实验设计科学、合理,可用于食品防腐剂防腐效能的评价。     

舍蝇抗菌肽的提取及其对肿瘤细胞生长的抑制作用

目的：研究含蝇抗菌肽的提取对肿瘤细胞生长的抑制作用；方法：对舍蝇幼虫采用针刺损伤及金黄色葡萄球菌感染诱导方法，并通过研磨、加热、阳离子交换柱层析及Sephadex G—50葡聚糖凝胶柱层析等步骤提取抗菌肽；结果：经SDS—PAGE电泳分离到2条带，分子量分别为4kD，9．6kD；结论：提取的舍蝇抗菌肽能有效地抑制人胃癌细胞MGC80—3和BGC—823，人乳腺癌细胞MCF—7及人肺癌细胞SPC—A—1的体外增殖，并且呈浓度依赖关系。     

Anti-Salmonella Activity and Peptidomic Profiling of Peptide Fractions Produced from Sturgeon Fish Skin Collagen (Huso huso) Using Commercial Enzymes

This study investigated peptide fractions from fish skin collagen for antibacterial activity against Escherichia coli and Salmonella strains. The collagen was hydrolyzed with six commercial proteases, including trypsin, Alcalase, Neutrase, Flavourzyme, pepsin and papain. Hydrolyzed samples obtained with trypsin and Alcalase had the largest number of small peptides (molecular weight <10 kDa), while the hydrolysate produced with papain showed the lowest degree of hydrolysis and highest number of large peptides. Four hydrolysates were found to inhibit the growth of the Gram-negative bacteria, with papain hydrolysate showing the best activity against E. coli, and Neutrase and papain hydrolysates showing the best activity against S. abony; hydrolysates produced with trypsin and pepsin did not show detectable antibacterial activity. After acetone fractionation of the latter hydrolysates, the peptide fractions demonstrated enhanced dose-dependent inhibition of the growth (colony-forming units) of four Salmonella strains, including S. abony (NCTC 6017), S. typhimurium (ATCC 13311), S. typhimurium (ATCC 14028) and S. chol (ATCC 10708). Shotgun peptidomics analysis of the acetone fractions of Neutrase and papain hydrolysates resulted in the identification of 71 and 103 peptides, respectively, with chain lengths of 6–22 and 6–24, respectively. This work provided an array of peptide sequences from fish skin collagen for pharmacophore identification, structure–activity relationship studies, and further investigation as food-based antibacterial agents against pathogenic microorganisms.     

Bioactive peptides from muscle sources: meat and fish

Bioactive peptides have been identified in a range of foods, including plant, milk and muscle, e.g., beef, chicken, pork and fish muscle proteins. Bioactive peptides from food proteins offer major potential for incorporation into functional foods and nutraceuticals. The aim of this paper is to present an outline of the bioactive peptides identified in the muscle protein of meat to date, with a focus on muscle protein from domestic animals and fish. The majority of research on bioactives from meat sources has focused on angiotensin-1-converting enzyme (ACE) inhibitory and antioxidant peptides.     

IN WHAT FORMS ARE DIGESTED PROTEINS ABSORBED FROM THE SMALL INTESTINE?

Despite recent evidence questioning the primacy of free amino acids as absorbable nitrogen, it seems premature to believe that peptides are the predominant form in which food proteins leave the intestinal lumen.     

Food Matrices Affect the Peptides Produced during the Digestion of Arthrospira platensis-Based Functional Aliments

Arthrospira platensis (Spirulina) has been credited with multiple beneficial effects, many of which are attributed to bioactive peptides produced during the gastrointestinal digestion of this micro-alga. Many Spirulina-based nutraceuticals have been produced, and numerous functional foods enriched with Spirulina are available on the market. These are subjected to checks aimed at verifying the amount of algae actually present, but few studies relating to the bioavailability of the bioactive compounds in these products have been carried out. However, such investigations could be very important to elucidate the possible critical effects exerted by food matrices on protein digestion and bioactive peptide production. Here, in order to assess the suitability of Spirulina-enriched foods as a source of potentially bioactive peptides, a simulated digestion protocol was used in combination with mass spectrometry quantitative analysis to analyze functionalized pasta and sorbets. In the case of the pasta enriched with Spirulina, the production of peptides was quite similar to that of the Spirulina powder. On the other hand, the type of fruit present in the food matrix influenced the digestion of Spirulina inside the sorbets. In particular, the high concentration of protease inhibitors in kiwifruit drastically reduced the production of peptides from Spirulina in kiwi sorbet.     

Identification and Characterization of Edible Cricket Peptides on Hypertensive and Glycemic In Vitro Inhibition and Their Anti-Inflammatory Activity on RAW 264.7 Macrophage Cells

Recent studies continue to demonstrate the potential of edible insects as a protein base to obtain bioactive peptides applicable for functional food development. This study aimed at identifying antihypertensive, anti-glycemic, and anti-inflammatory peptides derived from the in vitro gastrointestinal digests of cricket protein hydrolysates. After sequential fractionation, the protein digest subfraction containing the lowest molecular weight (<0.5 kDa), hydrophobic (C18) and cationic peptides (IEX) was found responsible for the most bioactivity. The cationic peptide fraction significantly reduced (p < 0.05) α-amylase, α-glucosidase, and angiotensin converting enzyme (ACE) activity in vitro, and also inhibited the expression of NF-κB in RAW 264.7 macrophage cells. A total of 28 peptides were identified with mass spectrometry (LC–MS/MS) and de novo sequencing from the potent fraction. Three novel peptides YKPRP, PHGAP, and VGPPQ were chosen for the molecular docking studies. PHGAP and VGPPQ exhibited a higher degree of non-covalent interactions with the enzyme active site residues and binding energies comparable to captopril. Results from this study demonstrate the bioactive potential of edible cricket peptides, especially as ACE inhibitors.     

家蝇抗菌肽对弓形虫的抑制作用研究

目的研究家蝇抗菌肽对弓形虫速殖子的抑制作用。方法对家蝇幼虫针刺感染细菌，诱导其产生抗菌肽，以离心法提取其血淋巴中所含的抗菌肽。结果家蝇血淋巴中抗菌肽有杀伤弓形虫速殖子的作用。结论提取的血淋巴中含有抑制弓形虫的成分。     

Identification of potential bioactive peptides generated by simulated gastrointestinal digestion of soybean seeds and soy milk proteins

In this work, the bioactive peptides produced during in vitro gastrointestinal digestion of soybean seeds and soy milk were investigated. The analysis was performed on extracted protein samples from soybean seeds and milk or directly on untreated soy milk. Proteins samples were subjected to simulated gastrointestinal digestion and then analyzed by nano-liquid chromatography coupled to tandem mass spectrometry for peptide sequencing. The identified peptides were 1173 in soybean seed samples, 1364 in untreated soy milk samples and 1422 in soy milk samples in which proteins were extracted by precipitation. The peptide identifications were then employed to search specific databases and look for the presence of bioactive peptides in the investigated samples, either with known biological activity or with potential antimicrobial activity. Results pointed out that soybean proteins underwent an extensive degradation process during gastrointestinal digestion and generated a large number of bioactive peptides, some with established activity, some with predicted antimicrobial activity. Finally, the supernatants collected after protein precipitation with acetone from both soybean seeds and soy milk were also analyzed to evaluate the presence of peptides produced by the action of endogenous proteases. Likely, peptides found in soy milk samples could be formed during food processing.     

抗病毒肽作用机制研究进展

抗病毒肽是一类具有抗病毒活性的生物小分子,通过特有的作用方式,其在体外或体内展示了良好的病毒抑制效应,有着良好的应用前景.此文就抗病毒肽的典型作用机制进行了综述.