Physical and Serologic Properties of an Antigen Prepared from Erythrocytes of Horses with Acute Babesiosis*

SYNOPSIS. By means of precipitation with protamine sulfate, a soluble antigen (PS) was obtained from erythrocytes of horses with acute babesiosis due to Babesia caballi and B. equi. This antigen reacted in gel diffusion tests with sera from horses recovered from acute babesiosis. The PS antigen was found to be muco-protein, susceptible to destruction by trypsin and taka-diastase. Analysis of the antigen by paper electrophoresis revealed 2 components which were not present in similar preparations made from erythrocytes of Babesia-free horses. When the PS antigen was heated in boiling water for 30 minutes, a serologically inactive precipitate was formed; however, the supernate remained serologically active and was termed boiled PS (BPS) antigen. This antigen was polysaccharide in nature; its serologic activity was destroyed by taka-diastase. In gel diffusion tests with sera of recovered horses, the PS antigen formed 2 lines of precipitation which coalesced in a single line formed between these sera and the BPS antigen. Both PS and BPS antigens reacted with sera of horses recovered from acute babesiosis in the gel-diffusion test, but not with sera of dogs and rats recovered from acute infection with Babesia canis and Babesia rodhaini, respectively. The serologic specificity of these antigens suggests that they might have application in the serodiagnosis of inapparent Babesia infections of equine animals.     

Novel tetranucleotide microsatellite markers from the Del Norte salamander (Plethodon elongatus) with application to its sister species the Siskiyou Mountain salamander (P. stormi)

Eleven tetranucleotide microsatellite loci were developed for the Del Norte salamander (Plethodon elongatus). The loci were variably polymorphic, ranging from two to 20 alleles per locus, with expected heterozygosities ranging from 0.07 to 0.86. The loci also amplified in a congener, the Siskiyou Mountain salamander (P. stormi). The microsatellite loci will be used to assess the utility of highly polymorphic markers to assay within‐ and between‐species differentiation between these two closely related species.     

Morphology, Performance and Fitness

Selection can be measured in natural populations by the changesit causes in the means, variances and covariances of phenotypiccharacters. Furthermore the force of selection can be measuredin conventional statistical terms that also play a key rolein theoretical equations for evolutionary change. The problemof measuring selection on morphological traits is simplifiedby breaking the task into two parts: measurement of the effectsof morphological variation on performance and measurement ofthe effects of performance on fitness. The first part can bepursued in the laboratory but the second part is best accomplishedin the field. The approach is illustrated with a hypotheticalanalysis of selection acting on the complex trophic morphologyof snakes.     

Behavior, Energy and Fitness

SYNOPSIS. Fitness relations in behavioral energetics can bestudied using the optimality approach (cost-benefit analysis),correlational analysis of selection, the experimental approachand the comparative method, as well as other approaches. Theseapproaches ask different questions, have different virtues anddifferent deficiencies. By using the approaches in combinationwe could gain new understanding of the relationships betweenbehavior, energy and fitness.