益生菌防治畜禽细菌性肠炎作用机制的研究进展

益生菌是一类对宿主机体有益、安全无害的活微生物,代替抗生素和疫苗广泛用于畜禽细菌性肠炎的防治。益生菌主要通过与病原菌竞争黏附位点、分泌抑菌物质、加固肠道黏膜屏障、调节肠道免疫应答等抑制病原菌增殖,缓解肠道炎症,防治细菌性肠炎的发生。本文对益生菌的作用机制进行了详细阐述,为益生菌的研究和应用提供参考。     

优良观赏保健树大叶冬青扩繁利用研究

在引进大叶冬青树种种质资源的基础上,系统地研究了大叶冬青生物学特性、生态适应性、生长习性、实生种播苗关键技术和组织培养及其微繁技术,以及生态复合拟生栽培技术,培育出了大叶冬青绿化苗木18万株。并测定了大叶冬青叶内可溶性蛋白质、超氧化物歧化酶(SOD)等抗衰老成分含量和叶组织中抗菌成分含量及其抑菌功能。因地制宜研制出优质嫩芽型、嫩叶炒青型、老叶微波干燥型3种苦丁保健绿茶,为大叶冬青叶资源产业化开发奠定了基础。     

Kaurane-type diterpenoids from Chromoleana odorata, their X-ray diffraction studies and potent α-glucosidase inhibition of 16-kauren-19-oic acid

A new diterpenoid, 15-angeloyloxy-16,17-epoxy-19-kauronic acid (1), along with five known metabolites, 16-kauren-19-oic acid (2), 6′-hydroxy-2′,3′,4,4′-tetramethoxychalcone (3), isosakuranetin (4), acacetin (5), and kaempferide (6) was isolated from the organic extracts of the roots of Chromoleana odorata. Their structures were determined by spectroscopic evidences. The structures of 1 and 2 were further confirmed by single-crystal X-ray diffraction studies. Compound 2 exhibited significant α-glucosidase inhibitory and antibacterial activities against Escherichia coli and Bacillus subtilis.     

Bioactive plants from Argentina and Bolivia

Antibacterial and molluscicidal activities of methanol and chloroform extracts of 16 plant species belonging to the families Compositae and Melastomataceae were evaluated. The chloroform extract of Vernonanthura tweediana and the methanol extract of Senecio santelisis resulted to be very toxic to brine shrimp nauplii (LC(50)=1 microg/ml). Chloroform extracts of S. santelisis and Senecio leucostachys as well as the methanol extract of Wedelia subvaginata displayed molluscicidal effects on Biomphalaria peregrina showing LC(100)<100 microg/ml. Moderate antibacterial action was produced by the chloroform extracts of Flaveria bidentis, Grindelia scorzonerifolia and Vernonia incana against two strains of Staphylococcus aureus.     

栗蚕蛹体液的一些免疫反应

为了探明栗蚕体内免疫机制,研究了栗蚕蛹体液免疫反应的某些特性。栗蚕蛹经细菌、真菌以及生理盐水诱导后,其体液对大肠杆菌(E.coli)、枯草杆菌(B.subtilis)、金黄色葡萄球菌(S.aureus)及柞蚕链球菌(T.streptoc-occus)均表现出一定的抑菌作用。大肠杆菌诱导6 h后,栗蚕蛹体液中出现抗菌活性物质,诱导后4 d,体液的抗菌活性达到高峰值,11 d后活性消失。SDS-PAGE电泳结果表明,诱导后的栗蚕蛹血淋巴中有新蛋白产生,推测可能与其产生新的抗菌活性有关。     

谷氨酰胺对断奶仔猪抗菌肽PR-39 mRNA的表达调控

本文旨在探讨谷氨酰胺(Gln)对断奶仔猪抗菌肽PR-39 mRNA表达的影响.选取64头胎次相同、28日龄断奶、体重(7.50±0.67)kg的三元杂交仔猪(杜×长×大),随机分为2个组,即基础日粮对照组和1.0%Gln添加组,每组设4个重复,每个重复8头猪(公母各1/2).于试验第28天,进行细胞因子白细胞介素-1β(IL-1β)、白细胞介素-6(IL-6)和肿瘤坏死因子(TNF-α)含量的分析.于第30天,采用半定量RT-PCR研究日粮中添加Gln对PR-39 mRNA的影响.试验结果表明:Gln添加显著提高仔猪血清中IL-1β含量(P<0.05),但对血清IL-6和TNF-α及空肠黏膜TNF-α、IL-2无显著影响(P>0.05);显著促使骨髓,空肠黏膜中PR-39 mRNA的表达(P<0.05),与对照组相比,骨髓和空肠黏膜中PR-39 mRNA分别提高50.5%(P<0.05)和24.0%(P<0.05).由结果可知,断奶仔猪日粮中添加Gln能显著促使骨髓及空肠黏膜PR-39 mRNA表达上调.     

Three new antibacterial active diarylheptanoids from Alpinia officinarum

Three new diarylheptanoids, together with ten known ones, were isolated from the ethanol extract from the rhizomes of Alpinia officinarum Hance. The structural identification of these compounds was mainly achieved by spectroscopic methods. The new compounds were elucidated as 7-(4″, 5″-dihydroxy-3″-methoxyphenyl)-1-phenyl -4-heptene-3-one (1), 1, 7-diphenyl-5-heptene-3-one (2) and 4-phenethyl-1, 7-diphenyl -1-heptene-3, 5-dione (3), respectively. All of the compounds showed antibacterial activity against Helicobactor pylori. Especially, the three new compounds showed strong antibacterial activity against Hp-Sydney strain 1 with the MIC values of 9–12 μg/mL, and against Hp-F44 with the MIC values of 25–30 μg/mL.     

在毕赤酵母中利用口蹄疫病毒(FMDV)2A实现dTomato和串联MagaininⅡ基因的共表达

抗菌肽(antibacterial peptides)是生物体内经诱导产生的一种具有生物活性的多肽,是天然免疫的重要组成部分.为了提高抗菌肽的表达量以及很方便地检测抗菌肽的表达情况,本研究利用口蹄疫病毒(Foot-and-mouth disease virus,FMDV) 2A将荧光蛋白dTomato基因和3个串联的MagaininⅡ基因融合到一个开放阅读框中(open reading frame,ORE),融合的基因被置于pPIC9K载体醇氧化酶基因(AOX1)启动子的下游,构建分泌型重组酵母表达载体pPIC9K-dTomato -2A-3M,将线性化的重组酵母表达载体通过电击法转入毕赤酵母(Pichia pastoris )GS115中,经G418筛选和PCR鉴定得到阳性转化子,然后将其转至摇瓶,在30℃、0.5％甲醇的条件下进行诱导表达,连续诱导3d.SDS-PAGE电泳图谱显示,在31 kD(dTomato)和9.5kD(3M)处有蛋白条带出现,在荧光显微镜下观察酵母表达上清发出红色荧光,对大肠杆菌(Escherichia coli)和金黄色葡萄球菌(Staphylococcus aureus)抑菌试验结果表明,重组抗菌肽串联的MagaininⅡ具有明显的抑菌效果.结果表明,由2A连接的融合基因(荧光蛋白dTomato和串联的MagaininⅡ)在毕赤酵母中成功的进行了表达,FMDV 2A在其C端剪切多聚蛋白,得到dTomato和串联的MagaininⅡ两个独立而有活性的蛋白,为小分子抗菌肽的表达提供一个高效的检测方法.     

环丙沙星对水产动物气单胞菌的药效学研究

环丙沙星为第三代步诺酮类药，是一种安全。高效的抗菌剂。该药对临床分离的几株致病性气单胞菌的最小抑制浓度（MIC）为0.0098μg/ml。人工感染治疗试验表明，该药以1mg/（kg.d）剂量灌服，连用5天，能有效控制鲫鱼败血症的暴发。     

癸甲溴铵对褐牙鲆的急性毒性及抑菌试验

通过药浴方式,进行了癸甲溴铵对褐牙鲆的急性毒性试验;采用二倍稀释法,进行了癸甲溴铵对鳗弧菌、副溶血弧菌的体外抑菌试验;探讨了癸甲溴铵对鳗弧菌引起的褐牙鲆细菌性疾病的防治效果。结果表明,在19.0～21.0℃和24.5～25.5℃时,癸甲溴铵对褐牙鲆的24、48h半数致死浓度(LC50)和安全浓度(Sc)分别为6.35、4.84、0.84和2.43、2.14、0.5mg/L。通过对中毒死亡褐牙鲆的病理组织学观察表明,癸甲溴铵对褐牙鲆的鳃损害最严重,其次是肝脏,对肾脏的损害相对较轻,特别是对鳃的损害与鱼的死亡有很大的关系。在24和32℃,癸甲溴铵对鳗弧菌、副溶血弧菌的最小抑菌浓度(MIC)和最小杀菌浓度(MBC)分别为10、20和5、10mg/L。防治效果试验表明,癸甲溴铵0.3mg/L浓度药浴可有效防治鳗弧菌引起的褐牙鲆细菌性疾病。