The Brucella genome at the beginning of the post-genomic era

The year 2002 began with the publication of the first complete genome sequence for a Brucella species, that of the two replicons of B. melitensis 16M. Hopefully in 2002, the complete genome of B. suis 1330, and, perhaps, a B. abortus strain will be published. This is the culmination of over 30 years investigation of the composition, structure, organisation and evolution of the Brucella genome. Brucella research must now adapt to the new challenges of the post-genomic era.     

制品生产用及地方疑难布氏菌DNA基因同源性的研究

本文以布氏菌19株国际标准菌种为对照,对国内外实验室参考菌种14株及地方疑难菌种11株结合常规方法进行了DNA G+Cmol％测定,同时以羊种菌M16 DNA为标准,与布氏菌所有种和型的24个代表株及8株地方疑难菌种进行了DNA-DNA杂交测定,布氏菌及地方疑难菌种的G+Cmol％值范围为54.1～59.3,M16株与布氏菌参考菌种的杂交率81.7～109％,与地方疑难菌种的杂交率除一株为72.1外,其余为84.2～109％,属高度同源,鉴定为布氏菌。本试验首次使用进口新仪器“PEKIN LAMBDA 17UV/Vis SPECTROPHOTOMETER”采用热变性法测DNA G+Cmol％,复性速率法进行DNA-DNA杂交,使杂交的DNA样品变性和复性在同一比色杯中进行,省去半导体点温计操作带来的麻烦,减小了实验误差,缩短测时,结果精确、操作简便、重复性好。     

提高布氏杆菌病虎红平板凝集试验抗原产量的研究

为提高布氏杆菌病虎红平板凝集试验抗原的产量,在生产中进行了一些探索,并对此进行分析、总结。     

Construction and Identification of an Induced Strain of Rough Brucella abortus

The purpose of the experiment was to study a new development method of brucellosis vaccine,and to successfully induce a rough Brucella abortus attenuated strain named RB71 by op inducer.Deletions of RB71-related genes were detected,The LPS integrity,growth characteristics,genetic stability,and viability in murine macrophage RAW264.7 cells were compared with those in smooth strains.The results showed that the mutant was successfully induced in the test,and the size of the missing fragment was 15 070 bp.The heat agglutination test was positive,which could be stained by crystal violet,and the acridine yellow agglutination test was positive.The extraction of lipopolysaccharide for silver staining showed that the O chain was deleted,and the induced strain RB71 lipopolysaccharide was incomplete.No gene mutation was detected by PCR after 30 consecutive passages.Under the same culture conditions in vitro,the growth rate of the induced strain RB71 was significantly lower than that of the parent strain A19.When infected with RAW264.7 macrophages in mice for 72 h,the intracellular survival rate was significantly reduced than that of the parent strain (P<0.01).In summary,this experiment successfully obtained an induced strain of Brucella RB71 with good genetic stability through the op inducer mutagenesis technique the survival ability of the induced strain in RAW264.7 cells was significantly weakened,which laid the technical foundation for the development of a new attenuated Brucella rough vaccine.     

规模化牛场奶牛衣原体和布鲁菌病相关抗体的检测分析

为检测并分析银川地区规模化牛场牛衣原体和布鲁菌病的相关抗体,采用鹦鹉热衣原体McAb-ELISA方法和布鲁菌虎红平板凝集试验(RBPT)方法进行特异性检测,应用McAb-ELISA方法与传统的IHA试验方法分别对同样50份待检牛血清进行衣原体抗体的比较检测。结果表明,银川地区的16个牛场1 161份牛血清衣原体总的阳性率为9.22%。布鲁菌的血清阳性率为13.26%。对50份牛血清采用2种试验方法同时进行衣原体抗体检测,ELISA阳性检出率为32%,IHA为24%。McAb-ELISA比IHA的特异性强。     

Investigations on the Prevalence of Bovine Tuberculosis and Brucellosis in Dairy Cattle in Dar es Salaam Region and in Zebu Cattle in Lugoba Area,Tanzania

A study between August 1995 and December 1997 included 343 dairy cattle on 20 farms in the Dar es Salaam region and 2289 zebu cattle on 39 bomas in the Lugoba area (coast region). The aim was to establish the prevalence of bovine tuberculosis (Mycobacterium bovis) and bovine brucellosis (Brucella abortus). In the single intradermal tuberculin test (SIT), 0.9% (3/343) of the animals in Dar es Salaam tested positive and 1.2% (4/343) were doubtful. Positive reactors were found in 10% (2/20) of the farms. In the Lugoba area, 0.6% (14/2206) were positive and 6.8% (149/2206) doubtful, positive cases being found in 21% (8/39) of all bomas. In the slow agglutination test (SAT) for B. abortus, 14.1% (48/341) of the serum samples reacted positively in Dar es Salaam and 2.3% (8/341) were doubtful. Positive SAT reactors were identified on 25% (5/20) of the dairy cattle farms. In the Lugoba area, 12.3% (273/2221) proved to be positive SAT reactors and doubtful reactions were observed in 2.9% (64/2221). SAT-positive animals were detected on 87% (34/39) of all bomas. The prevalence in single herds in Dar es Salaam varied from 4.3% to 5.3% for the SIT and from 2.2% to 50% for the SAT. The prevalence in single herds in Lugoba area was between 1.1% and 2.9% for SIT and from 1.4% up to 62.1% for SAT. The two cattle populations differed significantly (p<0.001) in the prevalence of both bovine tuberculosis and bovine brucellosis. Two cows that were positive reactors were slaughtered and subjected to post-mortem examination, and organ samples were bacteriologically cultured. The occurrence of Mycobacterium tuberculosis was confirmed by polymerase chain reaction (PCR) in both cows.     

Risk factors for brucellosis seroprevalence of sheep and goat flocks in Spain

Risk factors for ovine and caprine brucellosis in the Ávila region (center of Spain) were evaluated using data from a cross-sectional study of the most important diseases of small ruminants in this Spanish region between 1996 and 1997. Questionnaire data from 56 herds (35 ovine and 21 caprine) were used. Sixteen (29%) flocks (3 caprine and 13 ovine) were brucellosis-seropositive. Overall, 0.7% of sheep and 0.1% of goats were seropositive. Eleven risk factors were studied at the group level by logistic regression using flock brucellosis-status as outcome, and by linear regression using percentage of brucellosis-seropositivity as outcome. Both final models contained the same variables: contact with sheep and grazing in communal pastures as risk factors, and frequency of disinfecting practices as a protective factor.     

左旋咪唑对鸡细胞免疫和体液免疫功能的作用

系统研究了左旋咪唑对鸡细胞免疫和体液免疫功能的作用。结果表明左旋咪唑可影响正常鸡的免疫功能 :左旋咪唑可显著促进鸡外周血T淋巴细胞增殖 ,但对B淋巴细胞无明显影响 :2 5～ 1 0mg/kg左旋咪唑可使CD+4/CD+8淋巴细胞比值明显升高 ;左旋咪唑可使鸡体内抗颗粒性、胸腺依赖性抗原SRBC抗体滴度 ,抗可溶性、胸腺依赖性抗原BSA抗体滴度和抗非胸腺依赖性抗原BA抗体滴度均明显升高 ;2 5～ 1 0mg/kg左旋咪唑可使鸡血清总补体活性明显升高。左旋咪唑影响正常鸡回忆性免疫应答反应 :左旋咪唑 ( 1 0mg/kg)可使二次免疫鸡抗SRBC抗体滴度和抗BA抗体滴度回忆性免疫应答反应明显升高 ;但使鸡对抗BSA抗体滴度回忆性免疫应答反应明显降低。     

2022年宁夏固原市肉用流产母牛病原血清学调查分析

[目的]为了明确宁夏固原地区肉用流产母牛4种流产相关病原的流行情况。[方法]试验选择宁夏固原市5个地区不同规模化肉牛养殖场,采集131份有流产史的母牛血清样品,采用酶联免疫吸附试验（ELISA）分别对流产相关病原抗体/抗原进行检测和分析。[结果]采集的131份血清样品中共检出109份阳性血清,阳性率为83.2%。其中BVDV抗体阳性率为62.6%（82/131）、流产衣原体抗体阳性率为59.5%（78/131）、IBRV抗体阳性率为13.7%（18/131）,布鲁氏菌抗体阳性率为0%（0/131）。结果表明,采集的131份血清样品中共检出109份阳性血清,阳性率为83.2%。其中BVDV抗体阳性率为62.6%（82/131）、流产衣原体抗体阳性率为59.5%（78/131）、IBRV抗体阳性率为13.7%（18/131）,布鲁氏菌抗体阳性率为0%（0/131）。109份阳性样品中,最多出现3种病原混合感染。其中单一病原感染阳性样品占42.2%（46/109）,以BVDV感染比例最大,与流产衣原体阳性率相比差异显著（P＜0.05）;2种病原混合感染样品占56.9%（62/109）,以BVDV和流产衣原体混合感染比例最大,与流产衣原体和IBRV混合感染阳性率、BVDV和IBRV混合感染阳性率差异极显著（P＜0.01）;3种病原混合感染样本占4.6％（4/109）,主要以BVDV、流产衣原体和IBRV混合感染为主。[结论]宁夏固原地区流产母牛均存在以上3种疫病感染,其中主要以BVDV和流产衣原体单独或混合感染为主。     

布鲁氏菌抗体的无标记电流型免疫传感器检测

为提高布鲁氏菌抗体检测的检测限及灵敏度,并适应定量、快速的测定要求,以便早期发现病畜,减少经济损失,采用丝网印刷金电极表面修饰巯基乙胺绑定抗原的方法,研制了一种一次性免疫传感器。通过循环伏安法表征免疫电极的反应过程,发现布鲁氏菌抗体在10-5~10-3IU/mL浓度范围内,氧化峰电流的变化值(ΔIpa)与抗体的浓度呈良好的线性关系,其相关系数r=0.999 9,检测下限为2.8×10-5IU/mL。将测定的循环伏安曲线进行半微分变换,建立半微分变化值(Δepa)与浓度的关系,在10-5~10-3IU/mL浓度范围内,半微分氧化峰电流的变化值与浓度呈线性关系,相关系数r=0.992 9,检测下限为2.7×10-6IU/mL,且在10-2~1 IU/mL浓度范围内,半微分氧化峰电流的变化值与浓度的相关系数r=0.999 2。表明半微分变换可以明显改善其检测范围和检测下限。