羊支原体性肺炎两标准株对抗菌药物敏感性的研究

本实验测定了环丙沙星、氧氟沙星、单诺沙星、红霉素、罗红霉素、泰勒菌素、泰妙菌素、四环素等8种药物对羊肺炎支原体两个标准株Y98和Y-goat的体外抑菌浓度以及红霉素与氧氟沙星、泰勒菌素对Y-goat和四环素与氧氟沙星、泰勒菌素对Y98的联合药敏作用。对羊肺炎支原体两个标准株对抗菌药物的敏感性进行了分析。     

八种中草药体外抑制大肠杆菌的效果观察

选取马尾松、田基黄、艾草、雷公根、芭蕉芯、浮萍、野菊花、番石榴叶8种中草药，采用常规中草药药敏试验打孔法和试管法对猪大肠杆菌（K88）、大肠杆菌（0157）进行体外抑菌试验。结果显示，艾草、野菊花、番石榴叶对大肠杆菌呈高度敏感，其中艾草对大肠杆菌抑菌力最强；马尾松挥发油对大肠杆菌呈中度敏感；田基黄、雷公根、芭蕉芯、浮萍对大肠杆菌无抑菌作用。     

山羊传染性胸膜肺炎支原体和绵羊肺炎支原体对抗菌药物敏感性的研究

测定了环丙沙星、氧氟沙星、单诺沙星、红霉素、罗红霉素、泰乐菌素、泰妙菌素、四环素等8种药物对羊肺炎支原体两个标准株Y-98和Y-goat的体外抑菌浓度以及红霉素与氧氟沙星、泰乐菌素对Y-goat和四环素与氧氟沙星、泰乐菌素对Y-98的联合药敏作用.结果表明,这8种抗菌药物对Y-goat和Y-98的MIC(μg/mL)分别为:环丙沙星0.223、0.002 23,氧氟沙星0.281、0.014 0,单诺沙星0.136、0.014 0,红霉素0.021 8、无效,罗红霉素0.032 7、无效,泰乐菌素0.042 2、0.039 0,泰妙菌素0.021 7、0.052 0,四环素0.195、0.052 0.红霉素与氧氟沙星的联合药敏指数为1,是相加作用;红霉素与泰乐菌素对Y-goat的联合药敏指数为1.5,是无关作用;四环素与氧氟沙星、泰乐菌素对Y-98的联合药敏试验指数均为0.375,是协同作用.     

In Vitro Evaluation of the Effects of Selected Plants on the Growth of the Mycelial Form of Histoplasma capsulatum Variety farciminosum in Ethiopia

Epizootic lymphangitis is prevalent in equines in Ethiopia, causing remarkable economic and welfare impacts but often neglected. Lack of effective treatment contributed to its continued occurrence, and hence, search for an effective treatment should be considered a priority area to minimize its impacts. Previous ethnobotanical studies have reported that Curcuma longa, Phytolacca dodecandra, and Datura stramonium were used to treat cutaneous fungal infections and reduce their incidence. The treatment effects of these plants against epizootic lymphangitis should be studied. The in vitro growth inhibitory effects of methanol extracts of the root of C. longa, berry of P. dodecandra, and leaf of D. stramonium were evaluated. Histoplasma capsulatum var farciminosum was isolated from clinical cases of epizootic lymphangitis in carthorses in central Ethiopia. The nested polymerase chain reaction was used to confirm the identity of the isolates. Serial twofold dilutions of the extract of berries of P. dodecandra and leaves of D. stramonium were done in sterile water, whereas dilution of the extract of roots of C. longa was done in dimethylsulphoxide. The effects of the plants on the growth of Histoplasma capsulatum var farciminosum were assessed by agar dilution assay. Culture media with no antifungal agent and media containing ketoconazole served as negative and positive control, respectively. The methanol extract of C. longa showed inhibitory effects at concentrations ranging from 0.07 to 5 mg/mL. Similarly, the methanol extract of P. dodecandra showed growth inhibitory effects at concentrations ranging from 0.156 to 5 mg/mL. That is, the growth inhibitory concentration of C. longa was 0.07 mg/mL, whereas that of P. dodecandra was 0.156 mg/mL. In contrast, D. stramonium showed no inhibitory effect. This preliminary observation showed that methanol extracts of C. longa and P. dodecandra showed inhibitory effects on the growth of Histoplasma capsulatum var farciminosum requiring further repeated in vitro evaluation so as to generate adequate evidence, which would justify in vivo trials.     

In vitro susceptibility of Brachyspira hyodysenteriae to organic acids and essential oil components

The antibacterial potential of organic acids and essential oil components against Brachyspira hyodysenteriae, the causative pathogen of swine dysentery, was evaluated. Minimum inhibitory concentrations (MIC) of 15 compounds were determined at pH 7.2 and pH 6.0, using a broth microdilution assay. In addition, possible synergism was determined. MIC values for the three tested strains were similar. For organic acids, MIC values at pH 6.0 were lower than at pH 7.2. B. hyodysenteriae was most sensitive to cinnamaldehyde and lauric acid, with MIC values <1.5 mM. Most antibacterial effects of binary combinations were additive, however, for thymol and carvacrol, synergism could be observed. In vitro results demonstrate the antibacterial action of certain essential oil components and organic acids against B. hyodysenteriae.     

大蒜素对番茄叶霉菌不同生理小种的抑制作用

研究大蒜素对番茄生产上叶霉菌主流生理小种1.2.3.4以及2014年新发现生理小种2.5、2.4.5和1.2.3.4.9的抑制作用,为开发安全、高效的植物源农药奠定基础。首先制备大蒜素抽提母液,采用定硫法对其中的大蒜素进行定量测定,发现当溶液中滴加4 m L浓硝酸、溶液p H值为2.0时能够更为准确地测得大蒜素的含量,试验测得大蒜素含量为0.52%。在此基础上,进行了大蒜素对4个叶霉菌生理小种菌丝生长、孢子萌发的抑制试验,离体叶片上的病害预防试验以及苗期药效试验。结果表明,当大蒜素剂量25μL/m L时,其对叶霉菌生理小种菌丝生长的抑制活性较高,其中对1.2.3.4的抑制率最高,对1.2.3.4.9的抑制率最低,对其他2个生理小种的抑制率差异不显著。当大蒜素剂量7.5μL/m L时,其对4个生理小种孢子萌发的抑制效应存在差异,其中对1.2.3.4.9的孢子萌发抑制率最低,对1.2.3.4的孢子萌发抑制率最高。当大蒜素剂量为125μL/m L时,其对叶霉菌4个生理小种在离体叶片上的预防效果均超过95%。苗期药效试验表明,在相等剂量下,大蒜素对叶霉菌的防治效果高于多菌灵和甲基托布津,说明大蒜素是一种可以替代化学药剂防治叶霉病的有效抑菌物质。     

Comparative pharmacokinetics of marbofloxacin in healthy and Mannheimia haemolytica infected calves

The pharmacokinetics of marbofloxacin were investigated in healthy (n=8) and Mannheimia haemolytica naturally infected (n=8) Simmental ruminant calves following intravenous (i.v.) and intramuscular (i.m.) administration of 2 mg kg(-1) body weight. The concentration of marbofloxacin in plasma was measured using high performance liquid chromatography with ultraviolet detection. Following i.v. administration of the drug, the elimination half-life (t(1/2 beta)) and mean residence time (MRT) were significantly longer in diseased calves (8.2h; 11.13 h) than in healthy ones (4.6 h; 6.1 h), respectively. The value of total body clearance (CL(B)) was larger in healthy calves (3 ml min(-1) kg(-1)) than in diseased ones (1.3 ml min(-1) kg(-1)). After single intramuscular (i.m.) administration of the drug, the elimination half-life, mean residence time (MRT) and maximum plasma concentration (C(max)) were higher in diseased calves (8.0, 12 h, 2.32 microg ml(-1)) than in healthy ones (4.7, 7.4 h, 1.4 microg ml(-1)), respectively. The plasma concentrations and AUC following administration of the drug by both routes were significantly higher in diseased calves than in healthy ones. Protein binding of Marbofloxacin was not significantly different in healthy and diseased calves. The mean value for MIC of marbofloxacin for M. haemolytica was 0.1+/-0.06 microg ml(-1). The C(max)/MIC and AUC(24)/MIC ratios were significantly higher in diseased calves (13.0-64.4 and 125-618 h) than in healthy calves (8-38.33 and 66.34-328 h). The obtained results for surrogate markers of antimicrobial activity (C(max)/MIC, AUC/MIC and T > or = MIC) indicate the excellent pharmacodynamic characteristics of the drug in diseased calves with M. haemolytica, which can be expected to optimize the clinical efficacy and minimize the development of resistance.     

发酵法制备蛤蜊ACE抑制肽的菌种筛选

为筛选适用于发酵蛤蜊制备降血压活性多肽的纳豆芽孢杆菌,本试验从7种日本纳豆中初筛6株具有较高蛋白酶活性的纳豆芽孢杆菌株用于发酵蛤蜊,以体外血管紧张素转化酶(ACE)抑制率及多肽含量为评价指标筛选目的菌株。结果表明,共筛选出3株目的菌株(GL-5、GL~(-1)2和GL-25),其发酵产物对ACE抑制率分别为71.55%、78.31%、75.08%,多肽含量分别可达8.12、9.62、8.79mg·m L~(-1)。其中,GL~(-1)2发酵产物经消化酶水解后仍保持68.31%的ACE抑制率,表明其具有较强的抗消化能力。本研究结果为蛤蜊高值化利用开发具有降血压作用的功能食品提供了一定的理论依据。     

恩施藤茶乙醇提取物对高温煮熟鱼肉腐败菌的抑制作用研究

以生长菌落数为评价指标,研究恩施藤茶乙醇提取物对高温煮熟鱼肉的防腐效果;采用稀释平板法分离纯化和16S rDNA测序技术鉴定导致高温煮熟鱼肉腐败变质的细菌;运用滤纸片法测试恩施藤茶乙醇提取物对腐败变质细菌的抑菌活性;通过测定恩施藤茶乙醇提取物对腐败变质细菌生长曲线、导电率及生物大分子含量的影响研究其抑菌机理。结果表明:在储藏15 d内,30 mg·mL-1恩施藤茶乙醇提取物能完全抑制高温煮熟鱼肉中细菌生长;分离、鉴定了2株导致高温煮熟鱼肉腐败变质的细菌Bacillus methylotrophicus T-10、Alcaligenes faecalis T-9;恩施藤茶乙醇提取物对这2株腐败菌具有中敏抑菌活性(抑菌圈直径:10~20 mm),其最小抑菌浓度(MIC)分别为16.0 mg·mL-1和20.0 mg·mL-1;恩施藤茶乙醇提取物通过破坏菌体细胞膜的完整性,致使生物大分子物质外溢而发挥抑菌作用。