玉米肽研究进展

玉米蛋白肽在抗氧化和降血压、血脂、胆固醇方面具有显著效果。根据国内外相关研究进展,介绍玉米肽的主要制备提取方法,以及各提取方法的原理、优势和缺点,展望玉米肽的开发应用前景,为玉米肽的应用和开发研究提供理论参考。     

Antimicrobial Resistance Genes in Pigeons from Public Parks in Costa Rica

Antimicrobial resistance is known to be an emerging problem, but the extent of the issue remains incomplete. The aim of this study was to determine the presence or absence of nine resistance genes (bla_TEM, catI, mecA, qnrS, sulI, sulII, tet(A), tet(Q), vanA) in the faeces of 141 pigeons from four urban parks in Alajuela, Guadalupe, Tres Ríos and San José in Costa Rica. The genes were identified by real‐time PCR directly from enema samples. About 30% of the samples were positive for genes catI and sulI; between 13% and 17% were positive for qnrS, sulII, tet(A) and tet(Q); and 4% were positive for bla_TEM. The mecA and vanA genes were not detected. The average of antimicrobial resistance genes detected per pigeon was 2. Eight different patterns of resistance were identified, without differences in the sampling areas, being the most common pattern 2 (sulII positive samples). During rainy season, the genes more frequently found were sulI and tet(A). In conclusion, the urban inhabiting pigeons tested are currently carrying antimicrobial resistance genes, potentially acting as reservoirs of resistant bacteria and vectors to humans. To the authors’ knowledge, this is the first study carried out on direct detection of resistance genes in the digestive metagenomes of pigeons.     

天蚕素抗菌肽对817肉杂鸡生长性能及免疫功能的影响

试验旨在研究天蚕素抗菌肽对817肉杂鸡生长性能和免疫功能的影响。选取1日龄817肉杂鸡900羽,随机分为5个处理组（对照组、抗生素组及Ⅰ、Ⅱ、Ⅲ组）,每组6个重复,每个重复30羽。对照组饲喂基础日粮,抗生素组在基础日粮中添加150 mg/kg金霉素,Ⅰ、Ⅱ、Ⅲ组分别在基础日粮中添加100、200和300 mg/kg天蚕素抗菌肽,试验期42 d。结果显示,Ⅱ、Ⅲ组能显著提高1~21日龄817肉杂鸡的平均日增重（P<0.05）,显著降低料重比（P<0.05）;显著提高21、42日龄817肉杂鸡的胸腺、法氏囊和脾脏指数（P<0.05）;显著提高42日龄肉杂鸡的ND抗体水平和T淋巴细胞转化率（P<0.05）,表明在日粮中添加天蚕素抗菌肽能提高817肉杂鸡的生长性能和免疫功能,在本试验条件下,适宜的添加量为200 mg/kg。     

蛋氨酸三肽对奶牛乳腺上皮细胞酪蛋白和小肽转运载体基因表达量的影响

本试验旨在研究蛋氨酸三肽(Met-Met-Met)对奶牛乳腺上皮细胞(BMECs)酪蛋白和小肽转运载体基因表达量的影响。采用酶消化法培养的第3代奶牛乳腺上皮细胞为模型,各处理在培养基中分别添加0(对照)、40、50、60、70和80μg/mL的蛋氨酸三肽,每个处理5个重复,每个重复1个培养孔,分别培养细胞24、48和72h,检测奶牛乳腺上皮细胞的相对增殖率,整体试验重复2次,确定最佳培养时间;各处理在培养基中分别添加0(对照)、40、50、60、70和80μg/mL的蛋氨酸三肽,每个处理3个重复,每个重复1个培养孔,以最佳培养时间培养,用实时定量PCR法检测酪蛋白基因的表达量,确定适宜蛋氨酸三肽浓度,整体试验重复3次;以最佳培养时间和适宜蛋氨酸三肽浓度培养细胞,以未添加蛋氨酸三肽的培养基为对照,每个处理3个重复,每个重复1个培养孔,测定小肽转运载体基因的表达量,整体试验重复3次。结果表明:在培养基中添加蛋氨酸三肽培养奶牛乳腺上皮细胞24h时,相对增殖率最高;培养基中加入60μg/mL的蛋氨酸三肽培养细胞24h,αs1-酪蛋白和β-酪蛋白的基因表达量最高,同时发现奶牛乳腺上皮细胞中小肽转运载体1和小肽转运载体2基因表达量显著高于对照处理(P0.05)。综上所述,培养基中添加60μg/mL的蛋氨酸三肽能够提高奶牛乳腺上皮细胞酪蛋白和肽转运载体基因的表达量。     

Characterization of the cathelicidin cluster in the Japanese quail (Coturnix japonica)

The Japanese quail has several advantages as a low‐fat meat bird with high immunity against diseases. Cathelicidins (CATHs) are antimicrobial peptides that play an important role in innate immunity. The aim of this study was to characterize the CATH cluster in the Japanese quail (Coturnix japonica). The Japanese quail CATH (CjCATH) cluster, contains four CATH genes, as in the chicken. The coding sequences of CjCATHs exhibited >85.3% identity to chicken CATHs. The predicted amino acid sequences of the four CjCATH genes contained the cathelin‐like domain characteristic of CATH proteins. Polymorphisms were detected in the open reading frames (ORFs) of all CjCATH sequences. Two amino acid substitutions were observed in the antimicrobial region of the mature peptide of CjCATH2, and predicted to influence peptide function. CjCATH1 is expressed in lung, heart, bone marrow and bursa of Fabricius (BF). CjCATH2 is expressed in bone marrow. CjCATH3 is expressed in lung, heart, bone marrow, BF, tongue and duodenum. CjCATHB1 is expressed in bone marrow and BF. This study is the first to characterize CATH genes in the Japanese quail, and identifies novel antimicrobial peptide sequences belonging to the cathelicidin family, which may play a role in immunity in this species.     

Research Progress on Novel Peptide Epitopes Technology

As an important component of the antigen, peptide epitopes can be recognized by T cell receptor (TCR) and antibodies which induced protective immunity by the host immune system. Traditional research methods, such as overlapping peptide synthesis is long time-consuming which greatly limits the study of epitopes. With the development of bioinformatics, high-throughput sequencing, CRISPR/Cas9 technology, MS and other technologies and explaining the processing mechanism of TAP-dificient protein constantly, the research for epitopes is being perfect continually. In this article, some new methods to study epitopes were introduced, including computer prediction of B cell or T cell epitopes, identification of epitopes based on the structure and interaction of MHC and antigenic peptides, screening epitopes by means of high throughput sequencing, screening epitopes by means of newly genome editing, the up-to-date research in TAP-deficient T cell epitopes, etc. Finally,future prospect for research direction of peptides was further forecasted.     

参附养心汤对老年阳虚水泛型慢性心力衰竭患者心功能及血清IL-6、TNF-α、hs-CRP水平的影响

目的 观察参附养心汤治疗老年阳虚水泛型慢性心力衰竭的临床效果。方法 将老年阳虚水泛型慢性心力衰竭患者92例随机分为观察组和对照组,每组46例。对照组采用西医常规治疗,观察组在对照组治疗方法基础上给予参附养心汤治疗。治疗4周后,对两组患者临床疗效、脑钠肽（BNP）、6 min步行距离、心功能指标[左心室舒张末期容积（LVEDV）、收缩末期容积（LVESV）、左心室射血分数（LVEF）]及细胞炎性因子[白细胞介素-6（IL-6）、肿瘤坏死因子（TNF-α）、超敏C-反应蛋白（hs-CRP）]进行比较。结果 治疗4周后,观察组总有效率为89.1%,显著高于对照组71.7%,差异具有统计学意义（P<0.05）;观察组的BNP水平显著低于对照组,而6 min步行距离显著高于对照组,差异具有统计学意义（P<0.05）;观察组的LVEDV、LVESV均显著低于对照组,而LVEF高于对照组,差异具有统计学意义（P<0.05）;观察组的血清hs-CRP、IL-6及TNF-α水平均显著低于对照组,差异具有统计学意义（P<0.05）。结论 参附养心汤能显著改善老年阳虚水泛型慢性心力衰竭患者的心功能指标,降低BNP水平,减轻炎症反应,提高运动耐量,疗效显著。     

斑点叉尾(鱼回)LEAP2成熟肽在毕赤酵母中的表达及其抑菌活性

LEAP-2 (Liver expressed antimicrobial peptide-2) 抗菌肽是一类主要在动物肝脏中表达的小分子肽,其生物学活性来自成熟肽区域,它们在动物的免疫系统中发挥了重要作用。本文以斑点叉尾鮰 (Ictalurus punctatus) LEAP-2成熟肽(mLEAP2)为研究对象,拟通过建立毕赤酵母表达系统,实现mLEAP2在毕赤酵母中的重组DNA表达,以期获得具生物学活性的重组体mLEAP2 (rmLEAP2),为进一步研究其功能和扩大制备奠定基础。首先以既有的斑点叉尾鮰mLEAP2的原核表达载体“pET-32a-mLEAP2”为模板,通过PCR扩增,获得5’端含EcoRⅠ酶切位点、3’端含NotⅠ酶切位点及6×his标签的LEAP-2成熟肽基因mLEAP2,然后将其与真核表达载体pPIC9K连接,构建重组表达载体“pPIC9K-mLEAP2”;电转化至毕赤酵母GS115细胞中,经不同浓度G418和选择性培养基筛选,获得高拷贝酵母转化子;在29 ℃、250 r/m条件下,以0.5%的甲醇对其诱导表达120 h;采用固化金属离子亲和层析(IMAC)对表达产物进行纯化,通过MALDI-TOF/TOF质谱对纯化产物的结构进行分析和鉴定。结果表明：表达的重组体蛋白为预期的目的蛋白rmLEAP2,其表达量约2.2 mg/L;另一方面,抑菌实验结果显示rmLEAP2具有明显的抑制枯草芽孢杆菌(Bacillus subtilis)的活性。     

来源于植物的短肽LD-1对番茄灰霉病的抑制作用及其抗病性研究

短肽LD-1是从牛心朴子草根中新分离的具有抗菌活性的多肽。本文以番茄灰霉病为供试菌株,研究了短肽LD-1对番茄灰霉病的抑制作用及其抗病性。结果表明:短肽LD-1对番茄灰霉病菌菌丝生长及孢子萌发具有较好的抑制作用。离体试验中,短肽LD-1对番茄灰霉病菌菌丝生长抑制作用的EC50在24、48、72h分别为28.3051、30.2134、32.7427mg/L,对孢子萌发的EC50为16.6919mg/L;活体试验中,短肽LD-1对番茄灰霉病具有较好的防治效果,90mg/L短肽LD-1对番茄灰霉病防治效果达到74.24%。短肽LD-1能导致病菌芽管发育畸形,不能正常发育。短肽LD-1对番茄种子的萌发和根系生长具有明显的促进效果,并且经短肽LD-1处理后的番茄须根发达,须根数目明显增多,促进了番茄的生长发育,提高了抗病性。     

Optimization of hydrolysis conditions for the production of angiotensin-I converting enzyme-inhibitory peptides and isolation of a novel peptide from lizard fish (Saurida elongata) muscle protein hydrolysate

Lizard fish (Saurida elongata) muscle protein was hydrolyzed using neutral protease to produce protein hydrolysate (LFPH), and the hydrolysis conditions were investigated using response-surface methodology. The optimum conditions for producing peptides with the highest angiotensin-I converting enzyme (ACE)-inhibitory activity were the following: enzyme-to-substrate ratio of 10,000 U/g, temperature of 48 °C, pH 7.0, and hydrolysis time of 2 h. Under these conditions, the ACE-inhibitory activity of LFPH and the degree of hydrolysis were 84% and 24%, respectively. A novel ACE-inhibitory peptide was isolated from LFPH using ultrafiltration, Sephadex G-15, and high-performance liquid chromatography. The amino acid sequence of the ACE-inhibitory peptide was identified as Ser-Pro-Arg-Cys-Arg (SPRCR), and its IC₅₀ was 41 ± 1 µM.