ABSTRACT
Previously, we demonstrated unique insertion/deletion polymorphisms of equine histidine-rich glycoprotein (eHRG) with five genotypes composed of 45-bp or 90-bp deletions in the histidine-rich region of eHRG in Thoroughbred horses. Although leukocytes are typically used to collect DNA for genotyping, blood sampling from animals is sometimes difficult and invasive. Moreover, the method for extracting DNA from blood leukocytes involves complicated steps and must be performed soon after blood sampling for sensitive gene analysis. In the present study, we performed eHRG genotyping using DNA, isolated from oral mucosa swabs collected by rubbing the mucosa on the underside of the upper lip of horses and 100 mg of freshly excreted feces obtained by scraping their surface. In the present study, we performed eHRG genotyping using DNA isolated from oral mucosa swabs and feces of horses (18 Thoroughbreds, 17 mixed breeds, 2 warm bloods), and compared the accuracy of this method with that of the method using DNA from leukocytes. The DNA derived from oral mucosa swabs was sufficient in quantity and quality for eHRG genotyping. However, DNA derived from fecal samples requires a more sensitive detection system because of contamination with non-horse DNA, and the test quality is low. Collection of oral mucosa swabs is less invasive than blood sampling; further, oral swabs can be stored for a longer period in a specified high-quality solution. Therefore, collecting DNA samples from oral mucosa swabs is recommended for the genetic analysis of not only horses but also other animals that are not accustomed to humans.
ABSTRACT
Self-absorption in a plastic scintillation fiber can be utilized to determine the incident position of single beta particles. A dichroic mirror directs scintillation photons with shorter wavelengths to one Si photomultiplier and those with longer wavelengths to another. An index calculated from the two signals is a monotonic function of the distance between the tip of the fiber and the incident point. Once this relation is known, one can determine the distance from the two measurables. In an experiment, such a calibration curve was acquired to detect the position of a 90Sr source up to a distance of 240â cm. The average total number of photoelectrons for a single beta particle was about 15-17. Depending on the propagation distance in the scintillation fiber, they were unevenly divided by the two photodetectors.
ABSTRACT
Histidine-rich glycoprotein (HRG) is abundant plasma protein with various effects on angiogenesis, coagulation, and immune responses. Previously, we identified the base and amino acid sequences of equine HRG (eHRG) and revealed that eHRG regulates neutrophil functions. In this study, we first conducted a large-scale gene analysis with DNA samples extracted from 1700 Thoroughbred horses and identified unique insertion/deletion polymorphisms in the histidine-rich region (HRR) of eHRG. Here we report two types of polymorphisms (deletion type 1 [D1] and deletion type 2 [D2]) containing either a 45 bp or 90 bp deletion in the HRR of eHRG, and five genotypes of eHRG (insertion/insertion [II], ID1, ID2, D1D1, and D1D2) in Thoroughbred horses. Allele frequency of I, D1, and D2, was 0.483, 0.480, and 0.037 and the incidence of each genotype was II: 23.4%, ID1: 46.2%, ID2: 3.6%, D1D1: 23.1%, and D1D2: 3.7%, respectively. The molecular weights of each plasma eHRG protein collected from horses with each genotype was detected as bands of different molecular size, which corresponded to the estimated amino acid sequence. The nickel-binding affinity of the D1 or D2 deletion eHRG was reduced, indicating a loss of function at the site. eHRG proteins show a variety of biological and immunological activities in vivo, and HRR is its active center, suggesting that genetic polymorphisms in eHRG may be involved in the performance in athletic ability, productivity, and susceptibility to infectious diseases in Thoroughbred horses.
