title: HCl Treatment for Preventing Diapause Causes Ca2+ Efflux in Bombyx mori Eggs.
abstract: To elucidate the mechanism for preventing entry into embryonic diapause or breakdown of diapause in Bombyx mori by HCl and dimethyl sulfoxide (DMSO) treatment or a combination of cold and HCl treatment, we performed quantitative analysis of Ca2+ and Mg2+ in the chorion and egg content using inductively coupled plasma atomic emission spectrometry (ICP-AES). When diapause eggs that had been incubated at 25°C for 2 days from oviposition and at 4°C for an additional six days were treated with HCl solution, the amount of Ca2+ in the chorion and egg content after HCl treatment was reduced to one-seventh, as compared with the amount before treatment. In contrast, there was no change in the amount of Mg2+ with HCl treatment. The amount of Ca2+ in the HCl solution after the diapause eggs were treated increased 7.5-fold, as compared with that of eggs treated with water. Even when 17-day-old diapausing eggs were treated with HCl, which did not break diapause, the amount of Ca2+ in the chorion and egg content was reduced to one-fifth, as compared with the control. Meanwhile, changes in Ca2+ and Mg2+ contents were not observed in 12-hr-old diapause-destined eggs before or after treatment with DMSO, which effectively prevents diapause. These data may suggest that Ca2+ efflux from diapause eggs by HCl is not directly associated with preventing entry into diapause or breaking of diapause. In addition, we discovered that the amount of Ca2+ in diapause-destined eggs was more than 2.4-fold larger than in non-diapause-destined eggs.
authors.affiliation: 1 Depertment of Correlative Study of Physics and Chemistry, Graduate School of Integrated Basic Sciences, Nihon University, Setagaya-ku, Tokyo 156-8550, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Kitta
authors.forename: Sin-ichiro
authors.initials: S
authors.lastname: Okawa
authors.forename: Miho
authors.initials: M
authors.lastname: Saito
authors.forename: Keisuke
authors.initials: K
authors.lastname: Mase
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sawada
mesh_terms: D000818:Animals; D012831:Bombyx / Q000187:drug effects* / Q000502:physiology; D002118:Calcium / Q000378:metabolism*; D003080:Cold Temperature; D064666:Diapause, Insect / Q000187:drug effects* / Q000502:physiology; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D006851:Hydrochloric Acid / Q000494:pharmacology*; D008274:Magnesium / Q000378:metabolism; D010063:Ovum / Q000187:drug effects* / Q000502:physiology; D014867:Water / Q000737:chemistry
chemical_list: D014867:Water; D008274:Magnesium; D006851:Hydrochloric Acid; D002118:Calcium; D004121:Dimethyl Sulfoxide
keywords: Bombyx mori; Ca2+; DMSO; Embryonic diapause; HCl treatment; diapause prevention or breaking