Diapause Prevention Effect of Bombyx mori by Dimethyl Sulfoxide

Takayuki Yamamoto,Hiroshi Sawada,Keisuke Mase,Michael Polymenis

doi:10.1371/journal.pone.0064124

Takayuki Yamamoto, Hiroshi Sawada + Show 2 more

Open Access

https://doi.org/10.1371/journal.pone.0064124

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Journal: PloS one	Publication Date: May 13, 2013
Citations: 29	License type: CC BY 4.0

Affiliation: Kitasato University, Nihon University

Abstract

HCl treatment has been, for about 80 years, the primary method for the prevention of entry into embryonic diapauses of Bombyx mori. This is because no method is as effective as the HCl treatment. In this study, we discovered that dimethyl sulfoxide (DMSO) prevented entry into the diapause of the silkworm, Bombyx mori. The effect of diapause prevention was 78% as a result of treatment with 100% DMSO concentration, and the effect was comparable to that of the HCl treatment. In contrast, in the case of non-diapause eggs, hatchability was decreased by DMSO in a concentration-dependent manner. The effect of DMSO was restricted within 24 hours after oviposition of diapause eggs, and the critical period was slightly shorter than the effective period of the HCl treatment. DMSO analogs, such as dimethyl formamide (DMF) and dimethyl sulfide (DMS), did little preventive effect against the diapause. Furthermore, we also investigated the permeation effects of chemical compounds by DMSO. When treated with an inhibitor of protein kinase CK2 (CK2) dissolved in DMSO, the prevention rate of the diapause was less than 40%. This means that the inhibition effect by the CK2 inhibitor was the inhibition of embryonic development after diapause prevention by DMSO. These data suggest that DMSO has the effects of preventing from entering into the diapause and permeation of chemicals into diapause eggs.

Highlights

In many insects, development is arrested and diapause is initiated in a specific stage to ensure survival under unfavorable environmental conditions [1]
Diapause prevention effect of B. mori by dimethyl sulfoxide (DMSO) To elucidate the preventive effects of DMSO on embryonic diapause, we examined the effects of various concentrations of DMSO, effective treatment times, impact of treatment on the developmental stages, and effects of DMSO analogs
We investigated the relationship between developmental stages and the prevention effects by DMSO

Summary

Introduction

Development is arrested and diapause is initiated in a specific stage to ensure survival under unfavorable environmental conditions [1]. In the case of the silkworm, Bombyx mori, diapause occurs in the late gastrula stage of embryogenesis, when the embryonic cell cycle becomes arrested in the G2 phase [2,3]. The molecular and developmental mechanisms underlying diapause termination and subsequent embryogenesis of B. mori remain unexplained. It is essential to delineate embryonic development after diapause termination and before the initiation of the diapause phase [4,5,6,7,8,9,10,11,12,13,14]. The molecular mechanism of to prevent entry into the diapause by the HCl treatment is not yet understood. Several hypotheses for the effects of the HCl treatment have been proposed [16,17,18,19]

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