title: Development of the irradiation method for the first instar silkworm larvae using locally targeted heavy-ion microbeam.
abstract: To carry out the radio-microsurgery study using silkworm, Bombyx mori, we have already developed the specific irradiation systems for eggs and third to fifth instar larvae. In this study, a modified application consisting of the first instar silkworm larvae was further developed using heavy-ion microbeams. This system includes aluminum plates with holes specially designed to fix the first instar silkworm larvae during irradiation, and Mylar films were used to adjust energy deposited for planning radiation doses at certain depth. Using this system, the suppression of abnormal proliferation of epidermal cells in the knob mutant was examined. Following target irradiation of the knob-forming region at the first instar stage with 180-mum-diameter microbeam of 220 MeV carbon (12C) ions, larvae were reared to evaluate the effects of irradiation. The results indicated that the knob formation at the irradiated segment was specially suppressed in 5.9, 56.4, 66.7 and 73.6% of larvae irradiated with 120, 250, 400 and 600 Gy, respectively, but the other knob formations at the non-irradiated segments were not suppressed in either irradiation. Although some larva did not survive undesired non-targeted exposure, our present results indicate that this method would be useful to investigate the irradiation effect on a long developmental period of time. Moreover, our system could also be applied to other species by targeting tissues, or organs during development and metamorphosis in insect and animals.
authors.affiliation: Microbeam Radiation Biology Group, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma 370-1292, Japan. fukamoto.kana@jaea.go.jp
authors.forename: Kana
authors.initials: K
authors.lastname: Fukamoto
authors.forename: Koji
authors.initials: K
authors.lastname: Shirai
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Sakata
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Sakashita
authors.forename: Tomoo
authors.initials: T
authors.lastname: Funayama
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Hamada
authors.forename: Seiichi
authors.initials: S
authors.lastname: Wada
authors.forename: Takehiko
authors.initials: T
authors.lastname: Kakizaki
authors.forename: Sachiko
authors.initials: S
authors.lastname: Shimura
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Kenji
authors.initials: K
authors.lastname: Kiguchi
mesh_terms: D000818:Animals; D019521:Body Patterning / Q000528:radiation effects*; D012831:Bombyx / Q000196:embryology* / Q000254:growth & development / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D004867:Equipment Design; D019544:Equipment Failure Analysis; D020450:Heavy Ions; D007814:Larva / Q000254:growth & development / Q000528:radiation effects; D011829:Radiation Dosage; D014916:Whole-Body Irradiation / Q000295:instrumentation* / Q000379:methods