Comparative antigenic analysis of extracellular proteins of Bacteroides nodosus isolated from virulent and benign ovine footrot

Antigens in the extracellular protein (ECP) complexes of Bacteroides nodosus, isolated from sheep with either benign or virulent footrot, were studied by immunoelectrophoresis (IEP). Rabbit antisera against ECP from virulent and benign strains, were used in homologous and heterologous crossed IEP. Four precipitin peaks unique to the virulent strain, and five peaks unique to the benign strain were identified. In an attempt to characterize the different antigens in ECP, rabbit antisera were raised against an outer membrane protein (OMP, mol. wt. 35 000 daltons), pili and various proteases of virulent and benign strains of B. nodosus. No precipitin band was observed when ECP from both B. nodosus strains were reacted against anti-OMP and anti-pilus antisera. However, single precipitin bands unique to one protease from the benign strain and one protease from the virulent strain were identified. The results suggest that specific antigens other than proteases or pili are important in determining whether a B. nodosus isolate is virulent or benign.     

猪轮状病毒2型(PCV2)是潜在的“定时炸弹”吗?

对猪轮状病毒2型(PCV2)的研究,为全球探讨断奶后多系统消瘦综合征(PMWS)的特殊问题,提供了许多答案。但是本文提出了一些还需要特别注意的地方 ,用以避免其可能导致的“恶果”出现。过去几年里 ,在关于断奶后多系统消瘦综合征(PMWS)、猪轮状病毒病(PCVD )全球性的探讨中 ,已经对许多关于疾病流行特点的来源和特征进行了广泛的研究。猪血清中猪轮状病毒2型 (PCV2)抗体以及猪的组织样本的检测表明 ,至少从1969年起 ,猪轮状病毒2型 (PCV2)的抗体就已经存在于猪的群体中了。现在已经确定 ,从1986年起在西班牙和英国就发现了传统的PMWS…     

Anaerobes in periodontal disease in the dog: a review

As anaerobic sampling and culture techniques improved, the documented prevalence of anaerobic bacteria in periodontal disease has increased. The anaerobic bacteria have become more well-known in humans and consequently in dogs, since this species is a major model in periodontal studies. A review of the literature related to anaerobic flora is described.     

Ⅱ型猪圆环病毒--滴答作响的定时炸弹?

对Ⅱ型猪圆环病毒的研究为与猪断奶后多系统消耗性综合征在全球爆发有关的问题提供了大量答案,但还有一些方面迫切需要引起人们的关注,以便为可能出现的梦魇般的前景准备对策.     

Potential effects of glucocorticoids on serum iron concentration in dogs

Prednisone was give norally(2mg/kg b.i.d.) to seven healthy mixed breed dogs for 3 consecutive days. Serum iron concentration increased significantly (p < 0.05) from 142 +/- 26 micro g/dl (mean +/- SE) before a drug adminis- tration on Day 0 to a maximum of 307 +/- 47 micro g/dl on Day 2, and returned to the Day 0 value by Day 5. Mean total iron binding capacity did not vary more than 25% from the Day 0 value during the 9 day long study. The percent saturation of transferrin with iron increased from 33 +/- 6% on Day 0 to a maximum of 71 +/- 9% on Day 3. This determination had decreased to 34 +/- 3% on Day 5. No statistically significant changes occurred in these parameters studied in six control dogs that were not given the drug. To determine whether serum iron concentration might be correlated with endogenous serum cortisol concentration, these tests were determined in serum collected from nine dogs at 7 a.m., 3 p.m., and 11 p.m. each day for 3 consecutive days. Serum iron concentration was lower at 7 a.m. (147 +/- 9 micro g/dl) than at 3 p.m. (164 +/- 9 micro g/dl) or 11 p.m. (159 +/- 10 micro g/dl). Likewise serum cortisol was lower at 7 a.m. (1.29 +/- 0.18 micro g/dl) than at 3 p.m. (1.49 +/- 0.19 micro g/dl) or 11 p.m. (1.51 +/- 0.22 micro g/dl). There was a significant positive linear correlation between serum iron and serum cortisol concentrations when they were compared using mean values for each dog. From these studies, it appears that exogenously administered glucocorticoids and endogenous increases in serum cortisol concentrations may result in increased serum iron concentrations in dogs.     

Divergent selection for postweaning feed conversion in Angus beef cattle: II. Genetic and phenotypic correlations and realized heritability estimate.

A single generation divergent selection study, replicated four times (1983, 1984, 1985, and 1986), was conducted to assess genetic differences between progeny of high and low feed conversion sires in Angus beef cattle and to determine correlated response for weight gain (ADG140), feed intake (AVFD140), and BW (OFFTSTWT) in a time- (140-d) and fat-constant (8.9 mm) period. Realized heritability estimates for unadjusted (feed/gain; FEFF140; .26) and adjusted feed conversion (adjusted as recommended by the BIF, 1986; ADJFDEFF; .46) were obtained. The difference in heritability estimates reflects variation accounted for by adjustment for BW differences, and thus maintenance requirements, of individual progeny. Phenotypic and "pseudo" realized genetic correlations of FEFF140 with ADG140, AVFD 140, and OFFTSTWT were -.33 and -.66, .49 and -.26, and .15 and -.41, respectively. Phenotypic and "pseudo" realized genetic correlations of ADJFDEFF with ADG140, AVFD140, OFFTSTWT, and FEFF140 were -.54 and -.59, .30 and -.23, .27 and -.36, and .97 and .49, respectively. Subcutaneous fat (as estimated by ultrasonic measurement; BF140) had phenotypic and "pseudo" realized genetic correlations with FEFF140 of -.33 and .66, respectively, and with ADJFDEFF of -.44 and -.58, respectively.