在不同流行程度下对流产布氏杆菌 RB51 和 19 号苗的田间实验研究

评价在布氏杆菌病不同流行程度情况下用流产布氏杆菌RB51和19号苗免疫牛群 ,经过12个月后 ,牛体所产生的保护性免疫情况。实验动物为450头血清阴性母牛 :330头犊牛(3 -8个月龄) ,120头后备母牛(10-12月龄)。分别来源于A区(发病率为39 %)和B区(发病率为2%)。285头牛用RB51苗免疫一或二次 ,165头牛用19号苗免疫一次 ,剂量均为5×109个克隆单位。免疫后 ,分别从两组中抽取74(占26 %)和30头(占18 %)与血清阳性公牛交配 ,并在原先已感染的牛群中饲养。30天以后 ,所有接种19号苗的牛血清转阳 ,而285头RB51苗接种的牛群经血清学检测(包括琼脂免疫扩散)均为阴性结果 ,并且怀孕母牛及其第一胎犊牛也为阴性。由此可见 :RB51菌苗可用作活体免疫 ,且不产生影响血清学检测诊断的抗体滴度 ,保护率达100% ,可有效地抵抗B型流产布氏杆野毒侵袭 ,在配种前免疫 ,免疫期可持续至少一年。在相同条件下 ,RB51菌苗比19号苗有效可靠。     

Purification and characterization of a stable cysteine protease ervatamin B, with two disulfide bridges, from the latex of Ervatamia coronaria

Latex of the medicinal plant Ervatamia coronaria was found to contain at least three cysteine proteases with high proteolytic activity, called ervatamins. One of these proteases, named ervatamin B, has been purified to homogeneity using ion-exchange chromatography and crystallization. The molecular mass of the enzyme was estimated to be 26 000 Da by SDS-PAGE and gel filtration. The extinction coefficient (epsilon(1%)(280 nm)) of the enzyme was 20.5 with 7 tryptophan and 10 tyrosine residues per molecule. The enzyme hydrolyzed denatured natural substrates such as casein, azoalbumin, and azocasein with a high specific activity. In addition, it showed amidolytic activity toward N-succinyl-alanine-alanine-alanine-p-nitroanilide with an apparent K(m) and K(cat) of 6.6 +/- 0.5 mM and 1.87 x 10(2) s(-)(1), respectively. The pH optima was 6.0-6.5 with azocasein as substrate and 7.0-7.5 with azoalbumin as substrate. The temperature optimum was around 50-55 degrees C. The enzyme was basic with an isoelectric point of 9.35 and had no carbohydrate content. Both the proteolytic and amidolytic activity of the enzyme was strongly inhibited by thiol-specific inhibitors. Interestingly, the enzyme had only two disulfide bridges versus three as in most plant cysteine proteases of the papain superfamily. The enzyme was relatively stable toward pH, denaturants, temperature, and organic solvents. Polyclonal antibodies raised against the pure enzyme gave a single precipitin line in Ouchterlony's double immunodiffusion and typical color in ELISA. Other related proteases do not cross-react with the antisera to ervatamin B showing that the enzyme is immunologically distinct. The N-terminal sequence showed conserved amino acid residues and considerable similarity to typical plant cysteine proteases.     

Ultrasonographic findings in abdominal mast cell disease: a retrospective study of 19 patients

A retrospective survey from January 1989 to January 1999 of Tufts University Foster Hospital for Small Animals radiology records of 12 dogs and seven cats with cytologically or histopathologically confirmed abdominal mast cell disease was performed. Ultrasound changes in hepatic mast cell infiltration in dogs included a subjective increase in size, a diffuse increase in echogenicity, and one or more hypoechoic nodules. Ultrasound findings in the affected canine spleen included one or more hypoechoic nodules and a subjective increase in size. Two ultrasonographically unremarkable canine livers and one unremarkable spleen were found to be infiltrated by mast cells. The mast cell-infiltrated feline spleen was subjectively increased in size, mottled, irregular, or contained nodules. The affected lymph nodes in both dogs and cats were hypoechoic or inhomogeneous, subjectively increased in size, and rounded. Gastrointestinal involvement in cats was characterized by a thickened ileocecocolic junction or colon with loss of wall layering. Mast cells were not found in the gastrointestinal tract in any dog. One dog with mast cell infiltrate of the kidneys had multiple hypoechoic nodules in the cortex that distorted the outer contour of the kidney. Although these findings are not specific to the disease in either species, abdominal ultrasound is considered a useful tool for determining the extent of disease in small-animal patients with mast cell tumor if used in conjunction with histopathology or cytology.     

Dynamics of Moraxella bovis infection and humoral immune response to bovine herpes virus type 1 during a natural outbreak of infectious bovine keratoconjunctivitis in beef calves

Infectious bovine keratoconjunctivitis (IBK) is an acute disease caused by Moraxella bovis (Mb). Several factors may predispose animals to an IBK outbreak; one commonly observed is infection with bovine herpes virus type 1 (BHV-1). The aim of this study was to investigate the dynamics of BHV-1 virus infection and its relation with clinical cases of IBK in weaned calves from a beef herd with a high prevalence of lesions caused by Mb. Sampling was carried out in six stages and included conjunctival swabs for isolating Mb as well as blood samples for identifying antibodies specific for BHV-1. A score for IBK lesions after observing each eye was determined. The findings of this study showed a high prevalence of BHV-1 virus infection (100% of animals were infected at the end of the trial); 67% of animals were culture-positive for Mb, but low rates of clinical IBK (19% of calves affected) were detected at the end of the trial. These results suggest that infection with BHV-1 did not predispose these animals to IBK, and that Mb infection produced clinical and subclinical disease in the absence of BHV-1 co-infection.     

Effect of Storage Time and Temperature of Equine Epididymis on the Viability,Motion Parameters,and Freezability of Epididymal Sperm

The recovery of sperm from the epididymal cauda may be the last chance to obtain genetic material when sudden death or serious injuries occur in valuable stallions. However, the lack of technical knowledge regarding the storage and transportation of the epididymis often prevents the preservation of the sperm. Therefore, the aim of this study was to compare sperm parameters of sperm obtained immediately after orchiectomy with sperm recovered from epididymal cauda at different times after storage at 5°C and at room temperature (RT). For that, 48 stallions of different breeds were used. In group 1 (control group), eight stallions were used, and the harvest of the epididymal sperm was performed immediately after orchiectomy. In group 2, 40 stallions were used, which were divided into five groups according to the storage time of the epididymis after orchiectomy (6, 12, 18, 24, or 30 hours), making a total of eight stallions per group. One epididymis of each stallion was stored at 5°C, and the contralateral epididymis was stored at RT, both for the same period. The sperm parameters of total motility, progressive motility, progressive linear velocity, curvilinear velocity, percentage of rapid sperm, and plasma membrane integrity were evaluated in all the groups after sperm recovery, resuspension in a sperm freezing diluent, and thawing. In conclusion, the storage of the testis-epididymis complex at 5°C provided better preservation of epididymal sperm than the storage at RT, and regardless of the temperature, the progressive motility is the sperm parameter that is most sensitive to storage time.