title: Heat-Denatured Lysozyme Inactivates Murine Norovirus as a Surrogate Human Norovirus.
abstract: Human norovirus infects humans through the consumption of contaminated food, contact with the excrement or vomit of an infected person, and through airborne droplets that scatter the virus through the air. Being highly infectious and highly viable in the environment, inactivation of the norovirus requires a highly effective inactivating agent. In this study, we have discovered the thermal denaturing capacity of a lysozyme with known antimicrobial activity against gram-positive bacteria, as well as its inactivating effect on murine norovirus. This study is the first report on the norovirus-inactivating effects of a thermally denatured lysozyme. We observed that lysozymes heat-treated for 40 min at 100 °C caused a 4.5 log reduction in infectivity of norovirus. Transmission electron microscope analysis showed that virus particles exposed to thermally denatured lysozymes were expanded, compared to the virus before exposure. The amino acid sequence of the lysozyme was divided into three sections and the peptides of each artificially synthesised, in order to determine the region responsible for the inactivating effect. These results suggest that thermal denaturation of the lysozyme changes the protein structure, activating the region responsible for imparting an inactivating effect against the virus.
authors.affiliation: Department of Food Science and Technology, Faculty of Marine Science, Tokyo University of Marine Science and Technology, 4 -5-7, Konan, Minato-ku, Tokyo, 108-8477 Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Takahashi
authors.affiliation: Department of Food Science and Technology, Faculty of Marine Science, Tokyo University of Marine Science and Technology, 4 -5-7, Konan, Minato-ku, Tokyo, 108-8477 Japan.
authors.forename: Moemi
authors.initials: M
authors.lastname: Nakazawa
authors.affiliation: Department of Food Science and Technology, Faculty of Marine Science, Tokyo University of Marine Science and Technology, 4 -5-7, Konan, Minato-ku, Tokyo, 108-8477 Japan.
authors.forename: Chihiro
authors.initials: C
authors.lastname: Ohshima
authors.affiliation: 1] Department of Food Science and Technology, Faculty of Marine Science, Tokyo University of Marine Science and Technology, 4 -5-7, Konan, Minato-ku, Tokyo, 108-8477 Japan [2] Kewpie Corporation, Sengawa Kewport, 2-5-7, Sengawa-cho, Chofu-shi, Tokyo, 182-0002 Japan.
authors.forename: Miki
authors.initials: M
authors.lastname: Sato
authors.affiliation: Department of Food Science and Technology, Faculty of Marine Science, Tokyo University of Marine Science and Technology, 4 -5-7, Konan, Minato-ku, Tokyo, 108-8477 Japan.
authors.forename: Tomoki
authors.initials: T
authors.lastname: Tsuchiya
authors.affiliation: Kewpie Corporation, Sengawa Kewport, 2-5-7, Sengawa-cho, Chofu-shi, Tokyo, 182-0002 Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Takeuchi
authors.affiliation: Kewpie Corporation, Sengawa Kewport, 2-5-7, Sengawa-cho, Chofu-shi, Tokyo, 182-0002 Japan.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Kunou
authors.affiliation: Department of Food Science and Technology, Faculty of Marine Science, Tokyo University of Marine Science and Technology, 4 -5-7, Konan, Minato-ku, Tokyo, 108-8477 Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kuda
authors.affiliation: Department of Food Science and Technology, Faculty of Marine Science, Tokyo University of Marine Science and Technology, 4 -5-7, Konan, Minato-ku, Tokyo, 108-8477 Japan.
authors.forename: Bon
authors.initials: B
authors.lastname: Kimura
mesh_terms: D000818:Animals; D005516:Food Microbiology; D006094:Gram-Positive Bacteria / Q000472:pathogenicity; D006358:Hot Temperature; D006801:Humans; D051379:Mice; D009113:Muramidase / Q000737:chemistry*; D029322:Norovirus / Q000737:chemistry* / Q000472:pathogenicity; D011506:Proteins / Q000737:chemistry; D038301:Virus Inactivation
chemical_list: D011506:Proteins; D009113:Muramidase