环介导等温扩增法检测牛奶中结核分枝杆菌条件的优化

为优化环介导等温扩增（loop-mediated isothermal amplification,LAMP）法检测牛奶中结核分枝杆菌的条件,以结核分枝杆菌高度保守的16S rRNA基因为靶基因设计3对特异性引物（F3-B3、FIP-BIP、FLP-BLP）进行试验。比较改良后的CATB/NaCl法、细菌基因组DNA提取试剂盒及热裂解法提取其DNA的效率,确定最佳的提取方法。用灭菌处理过的牛奶对结核分枝杆菌悬液进行倍比稀释以确定该检测方法的敏感度。以牛奶中常见的布鲁氏菌、大肠杆菌、金黄色葡萄球菌、李斯特菌、巴氏杆菌、沙门氏菌为对照,对该方法进行特异性测试。结果表明,改良后的CTAB/NaCl法对牛奶中结核分枝杆菌DNA的提取效果要优于其他两种方法。LAMP法检测结核分枝杆菌的灵敏度为3×10⁰ CFU/mL,对人工阳性乳中结核分枝杆菌检测的灵敏度为3×10¹ CFU/mL。     

Field evaluation of the protective efficacy of Mycobacterium bovis BCG vaccine against bovine tuberculosis

The protective efficacy of Mycobacterium bovis BCG (1 × 10⁶ single dose) was evaluated under field conditions. A total of 140 male Holstein Friesian calves, one to two week-old were selected. Two groups of 70 each were formed, one group was vaccinated and the other was injected with a placebo during their second week of age and followed until 12 months of age. The study considered a positive case of tuberculosis to be an animal that had a positive reaction to the three following tests in a row: tuberculin, IFNγ PPD-B and IFNγ ESAT6-CFP10 during the 12 months of exposure. The results showed a 59.4% efficacy (IC95%: 47.64-71.16). The non-vaccinated calves were 2.4 times more at risk of becoming infected (IC95%: 1.07-5.68) compared to vaccinated animals. As a complementary test a PCR test was performed using nasal exudates in some animals from both groups using a Mycobacterium complex detection kit. All the positive PCR reactions (5/44) were found in the non-vaccinated animals. These findings suggest that the use of the BCG vaccine, even though it is not capable of protecting 100%, does prevent TB vaccinated animals from excreting bacilli in their nasal secretions at their first year of age.     

水貂源牛分枝杆菌的分离与荧光PCR鉴定

目的探讨水貂源结核杆菌复合群的检测方法,并进行病原学调查。方法利用7H10培养基分离水貂结核病的病原,采用荧光探针PCR方法进行检测。结果经鉴定分离的病原菌为致病性牛分枝杆菌。结论通过荧光探针PCR能够直接对结核杆菌复合群进行亚种鉴定,该方法具有快速、敏感、特异性强的优点,能够减少动物检疫时间。     

牛分枝杆菌RecA基因的克隆与序列分析

以牛分枝杆菌(Mycobacterium bovis)Valleelll株染色体DNA为模板,以RecA基因特异性引物进行PCR扩增,获得约240 bp的DNA片段.将PCR产物克隆至pMDTM18-T Vector中,通过α-互补法筛选、质粒PCR鉴定及序列分析鉴定,成功构建出了重组质粒pMDTM18-T-RecA,为进一步研究RecA基因及其在牛结核病诊断中的应用奠定了基础.     

生物体中位点2切割蛋白酶在致病菌致病机理方面的研究进展

膜内切割蛋白酶在信号传导过程中起着重要作用。Site-2 proteases（简称s2p）属于膜内切割蛋白酶中的金属蛋白酶类,如今在大多数细菌基因组中都发现了s2p。然而目前除了具有代表性的Rsep和SpolVFB蛋白酶被人们熟知之外,s2p更多的作用还未被发现。笔者就其实验结果以及结合最新关于s2p蛋白的研究数据,对s2p在细菌体内的生理生化作用及其在致病菌内致病过程中所起到作用展开一定的讨论。     

A non-radioactive DNA probe for detecting dicyandiamide-degrading soil bacteria

Some soil bacteria are capable of degrading the nitrification inhibitor dicyandiamide (DCD). One of the most efficient isolates is strain EK1 of Mycobacterium sp. For detecting this and closely related DCD-degrading bacteria in soil we developed a non-radioactive DNA probe. A 1.7-kb EK1 DNA fragment was selected from a genomic library and labelled with digoxigenin. The probe was highly specific for EK1 and closely related or identical species of soil bacteria. A method for direct detection of DNA from soil was developed. The sensitivity of this methodology allowed detection of 2×10³ EK1 cells g^–1 soil. Received: 15 July 1996     

副结核分支杆菌Hed蛋白的抗原性分析及在间接ELISA中的应用

从副结核分支杆菌K-10菌株克隆出840 bp的hed基因片段,插入原核表达载体pET-32a(+),转化至Escherichia coliBL21(DE3),在0.8 mmol.L-1 IPTG诱导下进行表达,纯化重组蛋白,将其进行Western-blot分析、小鼠免疫试验,包被ELISA板,建立间接ELISA方法。结果显示:重组蛋白具有良好的抗原性,方阵滴定法确定了间接ELISA方法的抗血清最佳稀释度(100倍)和抗原包被浓度(4.4μg.mL-1),该方法具有较好的特异性和敏感性。     

结核分枝杆菌三价DNA疫苗在奶牛体内诱导的免疫应答

[目的]研究结核分枝杆菌Ag85B、MPB64和MPT83抗原DNA疫苗在奶牛体内诱导的免疫应答.[方法]以PJW4303为载体,构建上述3种抗原基因的三价DNA疫苗,免疫6月龄荷斯坦奶牛3次.ELISA法检测免疫奶牛的特异性抗体滴度.利用双抗夹心ELISA定量测定免疫奶牛各月IFN-γ浓度.[结果]免疫前奶牛体内特异性抗体为阴性,1免、2免后抗体效价上升较缓,3免后抗体效价上升快.MPT83特异性抗体上升最快,抗体效价1:3200持续6个月;Ag85B特异性抗体效价1:3200持续2个月;MPT64特异性抗体效价较低.免疫奶牛中MPT83、Ag85B、MPT64三种蛋白诱导产生IFN-γ在3免后6个月到达最高,浓度分别为(1 098.95±16.5.03)、(711.45士110.43)、(355.06±72.76) pg/mL,阴性对照组PBS刺激IFN -γ浓度为(114.5±27.46)pg/mL.阴性对照与三种抗原相比,差异均极显著(P＜0.01).[结论]多价核酸疫苗能同时诱导机体产生细胞免疫应答和体液免疫应答,可能有利于增强疫苗对抗结核病的抗性.     

副结核分枝杆菌McAb的某些特性鉴定

以超声波粉碎的副结核分枝杆菌地方株Ｃ２抗原免疫Ｂａｌｂ／ｃ小鼠，经与ＮＳ－１骨髓瘤细胞三次融合，获得了３株能稳定分泌抗副结核分枝ＭｃＡｂ的杂交瘤细胞系，其染色体数目为７８－１１０条，分别为ＩｇＭ和ＩｇＧ２。应用间接ＥＬＩＳＡ法测定细胞培养液，腹水和血清效价为１０＾－２～１０＾－７。交叉试验证明，ＭｃＡｂＯ１与受试的各株副结核分枝杆菌反应强烈，与牛分枝杆菌和草分枝杆菌有微弱特异性抗原之一。ＳＤＳ－Ｐ     

Marine Macrolides to Tackle Antimicrobial Resistance of Mycobacterium tuberculosis

Tuberculosis has become a major health problem globally. This is worsened by the emergence of resistant strains of Mycobacterium tuberculosis showing ability to evade the effectiveness of the current antimycobacterial therapies. Therefore, the efforts carried out to explore new entities from many sources, including marine, are critical. This review summarizes several marine-derived macrolides that show promising activity against M. tuberculosis. We also provide information regarding the biosynthetic processes of marine macrolides, including the challenges that are usually experienced in this process. As most of the studies reporting the antimycobacterial activities of the listed marine macrolides are based on in vitro studies, the future direction should consider expanding the trials to in vivo and clinical trials. In addition, in silico studies should also be explored for a quick screening on marine macrolides with potent activities against mycobacterial infection. To sum up, macrolides derived from marine organisms might become therapeutical options for tackling antimycobacterial resistance of M. tuberculosis.