A comparative examination of swine sera for antibody to Aujeszky virus with the conventional and a modified virus-serum neutralization test and a modified direct complement fixation test.

Sera of pigs from élite breeding herds, of boars and sows collected at slaughter-houses, and of pigs from herds known to be infected, were examined for antibody to Aujeszky virus. The conventional and a modified virus-neutralizing antibody (VNA) test and a modified direct complement fixation (CF) test were employed. In simultaneous titrations of positive sera the modified VNA test gave titers approx. 4 log2 units above the titers obtained by the conventional test. The conventional VNA test was found insufficiently sensitive. Unspecific neutralization in the modified VNA test was infrequent in serum dilution 1/2 and rare in dilution 1/4. The GF tests on sera of slaughter sows and animals from known infected herds showed a remarkable consistency with the VNA tests. Inconsistent results were obtained with but few sera. Abt. 5 % of the sera could not be examined because of complement fixation with control antigen.     

Evaluation of a high-throughput nucleic acid extraction method for the detection of Mycobacterium avium subsp. paratuberculosis in bovine fecal samples by PCR

Johne’s disease (paratuberculosis) is an economically important disease of cattle worldwide. The disease is caused by Mycobacterium avium subsp. paratuberculosis (MAP), a fastidious gram-positive bacterium. PCR is increasingly used in diagnostic laboratories for the detection of MAP in fecal samples given the rapid test turnaround time and sensitivity and specificity comparable to fecal culture. However, efficient extraction of DNA for sensitive detection of MAP by PCR is affected by the complex lipid-rich cell wall of MAP and the presence of PCR inhibitors in feces. We evaluated a high-throughput nucleic acid extraction method (MagMAX core nucleic acid purification kit with mechanical lysis module) in conjunction with an hspX gene PCR for the detection of MAP from bovine fecal samples, which resulted in correct identification of all negative (13 of 13) and positive (35 of 35) proficiency test samples obtained from the National Veterinary Services Laboratories. In addition, all 6 negative and 50 of 51 positive diagnostic specimens tested were categorized correctly.     

诊断桑树黄化型萎缩病的新方法

本文探讨利用瑞氏染色法和旦尼氏染色法诊断桑树黄化型萎缩病的可能性。试验结果表明,用此方法,在病株枝条或主根的横切面上,韧皮部的病原寄生部位被染成兰色或青色,呈阳性反应,健株组织切片的韧皮部则不着色,呈阴性反应。可作为桑黄化型萎缩病病株的实验诊断手段。     

Update on the diagnosis of Haemophilus parasuis infection in pigs and novel genotyping methods

Haemophilus parasuis causes Gl?sser's disease as well as a number of other diseases in pigs. The diagnosis of H. parasuis-associated disease is usually established by clinical signs, pathological findings and bacterial isolation but diagnosis is complicated by the existence of non-virulent strains and the early colonisation of the upper respiratory tract of healthy piglets. Moreover, several strains can be found on a farm and even within a single animal so it is important to determine the specific strain that is causing the clinical outbreak. Recently, genotyping methods have been developed with the goal of correlating genotype with the degree of virulence of H. parasuis strains. The association between genotype and virulence in H. parasuis is challenging due to the lack of knowledge of the complete genomic sequence and virulence factors of this bacterium.     

Prevalence of Mycobacterium avium subspecies paratuberculosis (MAP) infection in suspected diarrhoeic buffaloes and cattle reporting at Veterinary University in India

Murrah buffaloes, best breed for milk production are native of Haryana state. They contributes significantly to the farmer’s income, livelihood and food (milk and meat) security, in the semi-tropical regions of North India. Johne’s disease though endemic in the domestic livestock of the country, but reports are not available in the buffaloes suffering from morbidity due to progressive weakness and diarrhoea. We estimated the status of JD in diarrhoeic buffaloes and cattle reporting at Veterinary Clinical Complex of Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar, Haryana, India, using conventional, serological and PCR assays.141 buffaloes suffering from chronic diarrhoea were screened to estimate sero-prevalence of MAP and 50.0 % young and 53.52 % adult animals were positive. Of 14 cattle screened, none of the young and 66.6 % adult cows were positive. In buffaloes, 66.1 and 6.77 %, fecal samples were positive in microscopy and IS900 PCR, respectively. Sero-prevalence of JD was very high in diarrhoeic buffaloes and cattle from Haryana state of India.Buffaloes positive for Mycobacterium avium subspecies paratuberculosis (MAP) infection had reduced total leukocyte count and lymphocytes.     

牦牛奶渣乳酸菌对虉草青贮品质的影响

为评价牦牛奶渣乳酸茵对藕草青贮饲料发酵品质和化学成分的影响,试验设置对照组（CK）和3个不同乳酸茵含量处理组（Nzl：0．1ml·kg-1FM;NZ2：0．3ml·kg-1FM;NZ3：0．5ml·kg—FM）,青贮60d后检测发酵品质和化学成分。试验表明：不同添加剂比例对藕草青贮饲料影响不同;NZ1和NZ3处理能够显著降低祷草青贮饲料的pH（P〈0．05）,具有较高的乳酸和乙酸含量（P〈0．05）,NZ3处理的中性、酸性洗涤纤维含量显著降低（P〈0．05）,说明牦牛奶渣乳酸茵可以改蒿草青贮饲料的发酵品质;随着添加浓度的增加赫草青贮饲料的可溶性碳水化合物和粗蛋白具有显著增加趋势,中、酸性洗涤纤维具有降低趋势,说明牦牛奶渣乳酸菌能够改籍草青贮饲料的营养价值;牦牛奶渣乳酸茵的最适添加量为0．5ml·kg-1FM。     

Urinary tract infections-microbial virulence determinants and reactive oxygen species

The human urinary tract is able to combat with the microbial invasion under normal circumstances. To cause urinary tract infection the organism has to evade the host defense mechanisms by possessing distinct properties which contribute to the virulence of the organism hence called virulence determinants Ninety percent of uncomplicated urinary tract infections are caused by Escherichia coli, hence the knowledge of the virulence determinants of this organism can be extrapolated to other uropathogenic organism as well. Virulence determinants of uropathogenic E. coli include adhesins, siderophore production, polysaccharide coating, hemolysin production, outer membrane proteins etc. The intestinal E. coli, which are the reservoir of E. coli for causing UTI, lack these virulence determinants. On the other hand these virulence determinants enable the organism to colonize and invade the urinary tract. In addition these are important in acquiring the nutrients in other wise nutrient deficient environment. Further, they also help the organisms in triggering an inflammatory response and hence bringing about pathological changes which leads to symptomatic UTI. Severity of symptomatic infections and tissue damage during the infective process depends upon the magnitude of the inflammatory response triggered by the uropathogen which in turn is dependent upon the amount of extrcellular release of reactive oxygen species by the phagocytic cells; hence role of antioxidants as an adjunct to antibiotics in the treatment of infective process needs to be evaluated further.     

猪传染性胃肠炎病毒S基因核酸疫苗免疫小鼠体液免疫功能变化的研究

本实验对TGEV S基因核酸疫苗免疫后体液免疫功能变化进行了研究,同时比较了两种核酸疫苗单独免疫小鼠后体液免疫应答的变化,证明重组核酸疫苗诱导小鼠产生体液免疫应答。     

Expression of receptors for luteinizing hormone,gastric-inhibitory polypeptide,and vasopressin in normal adrenal glands and cortisol-secreting adrenocortical tumors in dogs

Hypercortisolism caused by an adrenocortical tumor (AT) results from adrenocorticotropic hormone (ACTH)-independent hypersecretion of glucocorticoids. Studies in humans demonstrate that steroidogenesis in ATs may be stimulated by ectopic or overexpressed eutopic G protein-coupled receptors. We report on a screening of 23 surgically removed, cortisol-secreting ATs for the expression of receptors for luteinizing hormone (LH), gastric-inhibitory polypeptide (GIP), and vasopressin (V_1a, V_1b, and V₂). Normal adrenal glands served as control tissues. Abundance of mRNA for these receptors was quantified using quantitative polymerase chain reaction (QPCR), and the presence and localization of these receptors were determined by immunohistochemistry. In both normal adrenal glands and ATs, mRNA encoding for all receptors was present, although the expression abundance of the V_1b receptor was very low. The mRNA expression abundance for GIP and V₂ receptors in ATs were significantly lower (0.03 and 0.01, respectively) than in normal adrenal glands. The zona fasciculata of normal adrenal glands stained immunonegative for the GIP receptor. In contrast, islands of GIP receptor-immunopositive cells were detected in about half of the ATs. The zona fasciculata of both normal adrenal glands and AT tissue were immunopositive for LH receptor; in ATs in a homogenous or heterogenous pattern. In normal adrenal glands, no immunolabeling for V_1bR and V₂ receptor was present, but in ATs, V₂ receptor-immunopositive cells were detected. In conclusion, QPCR analysis did not reveal overexpression of LH, GIP, V_1a, V_1b, or V₂ receptors in the ATs. However, the ectopic expression of GIP and V₂ receptor proteins in tumorous zona fasciculata tissue may play a role in the pathogenesis of canine cortisol-secreting ATs.     

顶复门原虫电子转移链代谢及Ⅱ型NADH脱氢酶研究进展

顶复门原虫是包括刚地弓形虫、疟原虫及球虫等在内的一大类寄生性原虫的总称,可引起重要的人畜寄生虫病.抗顶复门原虫药物的长期使用,甚至是滥用,使得这类寄生虫对现有药物产生了明显的抗药性,急需开发新型药物.Ⅱ型NAD(P)H脱氢酶是电子转移链途径中的关键酶,由于其仅存在于某些植物、细菌、真菌和寄生原虫等一些低等生物体内,而在高等动物体内缺失,是研发新型抗感染性药物的重要靶标.笔者主要针对顶复门原虫线粒体电子转移链代谢途径以及Ⅱ型NAD(P)H脱氢酶的研究概况进行综述.