title: Inactivation of Bombyx mori macula-like virus under physical conditions.
abstract: The Bombyx mori macula-like virus (BmMLV) is a member of the genus Maculavirus, family Tymoviridae, and contains a positive-sense single-stranded RNA genome. Previously, we reported that almost all B. mori-derived cell lines have already been contaminated with BmMLV via an unknown infection route. Since B. mori-derived cell lines are used for the baculovirus expression vector system, the invasion of BmMLV will cause a serious safety risk in the production of recombinant proteins. In this study, to determine the inactivation effectiveness of BmMLV, viruses were treated with various temperatures as well as gamma and ultraviolet (UV) light radiation. After these treatments, the virus solutions were inoculated into BmMLV-free BmVF cells. At 7 days postinoculation, the amount of virus in cells was evaluated by real-time reverse transcription PCR. Regarding heat treatment, conditions under 56°C for 3 h were tolerated, whereas infectivity disappeared after treatment at 75°C for 1 h. Regarding gamma radiation treatment, viruses were relatively stable at 1 kGy; however, their infectivity was entirely eliminated at a dose of 10 kGy. With 254 nm UV-C treatment, viruses were still active at less than 120 mJ/cm(2); however, their infectivity was completely lost at greater than 140 mJ/cm(2) UV-C radiation. These results provide quantitative evidence of the potential for BmMLV inactivation under a variety of physical conditions.
authors.affiliation: Department of Agrobiology and Bioresources, Faculty of Agriculture, Utsunomiya University, Mine-machi 350, Utsunomiya-shi, Tochigi, 321-8505, Japan.
authors.forename: Kodai
authors.initials: K
authors.lastname: Uchiyama
authors.affiliation: Department of Quality Assurance and Radiological Protection, National Institute of Infectious Diseases, Toyama 1-23-1, Shinjuku-ku, Tokyo, 162-8640, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Fujimoto
authors.affiliation: Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo, 113-8657, Japan.
authors.forename: Susumu
authors.initials: S
authors.lastname: Katsuma
authors.affiliation: Genebank, National Institute of Agrobiological Science, Kannondai 2-1-2, Tsukuba-shi, Ibaraki, 305-8602, Japan.|PrevenTec, Inc., Owashi 1-2, Tsukuba-shi, Ibaraki, 305-0851, Japan.
authors.forename: Shigeo
authors.initials: S
authors.lastname: Imanishi
authors.affiliation: Department of Quality Assurance and Radiological Protection, National Institute of Infectious Diseases, Toyama 1-23-1, Shinjuku-ku, Tokyo, 162-8640, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kato
authors.affiliation: Department of Agrobiology and Bioresources, Faculty of Agriculture, Utsunomiya University, Mine-machi 350, Utsunomiya-shi, Tochigi, 321-8505, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Kawasaki
authors.affiliation: Department of Agrobiology and Bioresources, Faculty of Agriculture, Utsunomiya University, Mine-machi 350, Utsunomiya-shi, Tochigi, 321-8505, Japan. iwanaga@cc.utsunomiya-u.ac.jp.
authors.forename: Masashi
authors.initials: M
authors.lastname: Iwanaga
mesh_terms: D000818:Animals; D016367:Baculoviridae / Q000235:genetics; D012831:Bombyx / Q000821:virology*; D002460:Cell Line; D005720:Gamma Rays; D006358:Hot Temperature; D012367:RNA, Viral / Q000528:radiation effects*; D046830:Tymoviridae / Q000472:pathogenicity / Q000528:radiation effects*; D014466:Ultraviolet Rays; D038301:Virus Inactivation / Q000528:radiation effects*
chemical_list: D012367:RNA, Viral
keywords: BEVS; BmMLV; Gamma radiation; Heat inactivation; Maculavirus; UV-C radiation