title: Development of a method for long-term preservation of Bombyx mori silkworm strains using frozen ovaries.
abstract: Development of long-term preservation is essential for conservation of stocks of silkworm genetic resources. Thus far, a few methods have been reported, but more improvement is required for practical use. We have developed two effective modifications of a method for long-term preservation using frozen ovaries. One was slow cooling (1 °C per min) until -80 °C of the donor ovaries made possible by use of a BICELL freezing vessel. Using donor ovaries of 4th instar larvae, the average number of eggs laid per moth increased significantly from 110.7 ± 53.4 eggs per moth by slow cooling with the BICELL vessel vs 12.3 ± 10.3 eggs per moth by direct cooling in liquid nitrogen. A second improvement was connecting the thread bodies of the donor ovaries with those of the host in the transplantation step. Females operated on with the new method yielded a significantly higher percentage of moths that laid fertilized eggs than those transplanted with the standard procedure (70.4 ± 21.6% vs 22.9 ± 9.3%).
authors.affiliation: Institute of Genetic Resources, Graduate School of Bio Resources and Bioenvironmental Science, Kyushu University, Higashi-ku, Fukuoka 812-8581, Japan. banno@agr.kyushu-u.ac.jp
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Banno
authors.forename: Kiyomi
authors.initials: K
authors.lastname: Nagasaki
authors.forename: Marino
authors.initials: M
authors.lastname: Tsukada
authors.forename: Yuko
authors.initials: Y
authors.lastname: Minohara
authors.forename: Junko
authors.initials: J
authors.lastname: Banno
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Nishikawa
authors.forename: Kazunori
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Kei
authors.initials: K
authors.lastname: Tamura
authors.forename: Tsuguru
authors.initials: T
authors.lastname: Fujii
mesh_terms: D000818:Animals; D012831:Bombyx / Q000235:genetics / Q000502:physiology*; D015925:Cryopreservation / Q000379:methods / Q000662:veterinary*; D005260:Female; D005615:Freezing; D007814:Larva / Q000502:physiology; D010053:Ovary / Q000502:physiology* / Q000637:transplantation*; D015053:Zygote / Q000502:physiology