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…     

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.     

Transmutation and functional representation of heterogeneous landscapes

Models of local small-scale ecological processes can be used to describe related processes at larger spatial scales if the influences of increased scale and heterogeneity are carefully considered. In this paper we consider the changes in the functional representation of an ecological process that can occur as one moves from a local small-scale model to a model of the aggregate expression of that process for a larger spatial extent. We call these changes spatial transmutation. We specifically examine landscape heterogeneity as a cause of transmutation. Spatial transmutation as a consequence of landscape heterogeneity is a source of error in the prediction of aggregate landscape behavior from smaller scale models. However, we also demonstrate a procedure for taking advantage of spatial transmutation to develop appropriately scaled landscape functions. First a mathematical function describing the process of interest as a local function of local variables is defined. The spatial heterogeneity of the local variables is described by their statistical distribution in the landscape. The aggregate landscape expression of the local process is then predicted by calculating the expected value of the local function, explicitly integrating landscape heterogeneity. Monte Carlo simulation is used to repeat the local-to-landscape extrapolation for a variety of landscape patterns. Finally, the extrapolated landscape results are regressed on landscape variables to define response functions that explain a useful fraction of the total variation in landscape behavior. The response functions are hypotheses about the functional representation of the local process at the larger spatial scale.     

A 31P topical magnetic resonance study of embryonic development in hens' eggs

1. A ³¹P topical magnetic resonance study of whole chicken's eggs in vivo is described.

2. Resonances from adenosine triphosphate, phosphocreatine, inorganic phosphate and phosphorous storage protein were observed. These changed in relative intensity as the embryo developed.

3. No ill effects due to exposure to radiofrequency radiation or magnetic fields were observed.

4. It is concluded that topical magnetic resonance can make a useful contribution to the study of embryonic development in avian eggs.     

An improved ferritin assay for canine sera

An improved serum ferritin assay for canine serum has been developed. It uses two monoclonal antibodies in a sandwich arrangement. Serum ferritin can be determined on undiluted canine sera with this assay. The recovery of ferritin added to canine serum ranged from 98 to 106%, the within-assay coefficient of variability was 3.3 to 4.5%, and the assay-to-assay variability was 9.8 to 10.2%. Serum ferritin from 61 apparently healthy dogs had a geometric mean of 252 ng/ml, with a range of 80 ng/ml to 800 ng/ml.     

Influence of age,sex, capture technique,and restraint on hematologic measurements and serum chemistries of wild California sea otters

Hematologic and/or serum chemical analyses were done on a total of 27 non-tranquilized adult and juvenile wild sea otters, 66 tranquilized adult and juvenile wild sea otters, and 26 wild sea otter pups. The median and inner 90 percentile range were determined for the adult, juvenile, and pup groups and for the following subgroups: adult male versus adult female, juvenile male versus juvenile female, pup male versus pup female, captured with dip net versus captured with Wilson trap, and tranquilized adults and juveniles versus non-tranquilized adults and juveniles. When values for adults were compared to values for juveniles and pups, hematocrits, red blood cell counts, and hemoglobin levels were significantly lower in pups. This is consistent with documented findings in other species. White cell counts were also somewhat lower in younger animals. Among the subgroups, significantly higher hemoglobin levels, white cell counts and neutrophil counts were found in adult females than in adult males. This is in direct contrast to what is seen in other mammalian species and warrants further documentation. Method of capture and tranquilization did not appear to influence either hematologic or serum biochemical determinations from a clinical perspective.