Obihiro University of Agriculture and Veterinary Medicine

I focus on host-parasite interactions with modified physiological condition of host animals using the transgenic technology. A target for protozoan infection might be host animals as well as parasites. In addition, techniques for reproductive bio-technology, one of the basic techniques of transgenic technology, are developing in the Research Unit for Functional Genomics.
Alpha-tocopherol transfer protein (α-TTP) is known to be a determinant of the plasma concentration of α-tocopherol (vitamin E), a lipid soluble ant-oxidant, in the body. Thus, α-TTP gene disruption induces vitamin E deficiency, undetectable level of vitamin E in circulation, in animals. When α-TTP knockout mice were infected with murine malarial parasites such as Plasmodium berghei NK65 and P. yoelli, their survival after the infection significantly extended as compared with wild type animals. The resistance phenotype against the protozoan infection were also seen in α-TTP knockout mice inoculated with trypanosoma congolense, a causing agent of Sura in domestic animals. Biochemical and molecular biological analysis revealed that proliferation of the infected parasites were inhibited by DNA damage derived from oxidative stress in circulation. In addition, α-TTP knockout mice infected with P. berghei ANKA, known to be able to induce cerebral malaria in mice, did not show any typical clinical symptom regarding cerebral malaria including blood brain barrier breakdown. These results indicate that inhibition of α-TTP activity might be a new approach for prevention and treatment of the protozoan infection in both human and other mammalian species.
Our techniques in reproductive bio-technology are applied for the improved breeding of the guide dogs for the blind people. Many countries including Japan suffer from an acute shortage of guide dogs. We have developed a novel cryoprotectant for canine spermatozoa for extension of artificial insemination technique in guide dog in Japan. More recently, we have successfully produced seven puppies derived from frozen embryos after the embryo transfer for the first time in the world. furthermore, control of zoonotic infection between dogs and humans may be an important factor for distribution and extension of the guide dog for the blind.

• Effect of vitamin E defficiency on protozoan infection.
• Analysis of pregnant malaria in mice.
• Analysis of reproductive ability in male infected with malaria.
• Cryopreservation of emmbryo, sperm and ovary in dog.
• Establishment of Babesia resistant cattle.