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Heat-Denatured Lysozyme Inactivates Murine Norovirus as a Surrogate Human Norovirus.

Takahashi H, Nakazawa M, Ohshima C, Sato M, Tsuchiya T, Takeuchi A, Kunou M, Kuda T, Kimura B - Sci Rep (2015)

Bottom Line: Being highly infectious and highly viable in the environment, inactivation of the norovirus requires a highly effective inactivating agent.We observed that lysozymes heat-treated for 40 min at 100 °C caused a 4.5 log reduction in infectivity of norovirus.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.

View Article: PubMed Central - PubMed

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.

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.

No MeSH data available.


Related in: MedlinePlus

Transmission electron microscope image of (a) untreated murine norovirus −1(MNV-1) particles, (b) The MNV-1 particles exposed to the lysozyme solution for 1 min, (c) The MNV-1 particles exposed to the thermally denatured lysozyme for 1 min, (d) The MNV-1 particles exposed to the thermally denatured lysozyme for 1 hour.
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f3: Transmission electron microscope image of (a) untreated murine norovirus −1(MNV-1) particles, (b) The MNV-1 particles exposed to the lysozyme solution for 1 min, (c) The MNV-1 particles exposed to the thermally denatured lysozyme for 1 min, (d) The MNV-1 particles exposed to the thermally denatured lysozyme for 1 hour.

Mentions: The transmission electron microscopy (TEM) was used to confirm the expansion characteristics of MNV particles exposed to denatured lysozyme solution (40 min at 100 °C) (Fig. 3). In comparison to the MNV particles not exposed to the lysozyme solution, which expressed a particle size of 35.45 ± 1.70, the MNV particles exposed (1 min) to the thermally denatured lysozyme showed an average expansion of 13.64 nm (49.09 ± 2.12) (Table 1).


Heat-Denatured Lysozyme Inactivates Murine Norovirus as a Surrogate Human Norovirus.

Takahashi H, Nakazawa M, Ohshima C, Sato M, Tsuchiya T, Takeuchi A, Kunou M, Kuda T, Kimura B - Sci Rep (2015)

Transmission electron microscope image of (a) untreated murine norovirus −1(MNV-1) particles, (b) The MNV-1 particles exposed to the lysozyme solution for 1 min, (c) The MNV-1 particles exposed to the thermally denatured lysozyme for 1 min, (d) The MNV-1 particles exposed to the thermally denatured lysozyme for 1 hour.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4488868&req=5

f3: Transmission electron microscope image of (a) untreated murine norovirus −1(MNV-1) particles, (b) The MNV-1 particles exposed to the lysozyme solution for 1 min, (c) The MNV-1 particles exposed to the thermally denatured lysozyme for 1 min, (d) The MNV-1 particles exposed to the thermally denatured lysozyme for 1 hour.
Mentions: The transmission electron microscopy (TEM) was used to confirm the expansion characteristics of MNV particles exposed to denatured lysozyme solution (40 min at 100 °C) (Fig. 3). In comparison to the MNV particles not exposed to the lysozyme solution, which expressed a particle size of 35.45 ± 1.70, the MNV particles exposed (1 min) to the thermally denatured lysozyme showed an average expansion of 13.64 nm (49.09 ± 2.12) (Table 1).

Bottom Line: Being highly infectious and highly viable in the environment, inactivation of the norovirus requires a highly effective inactivating agent.We observed that lysozymes heat-treated for 40 min at 100 °C caused a 4.5 log reduction in infectivity of norovirus.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.

View Article: PubMed Central - PubMed

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.

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.

No MeSH data available.


Related in: MedlinePlus