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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

Estimation of MNV-1 particles after exposed to distilled water, untreated lysozyme for 1 min, heat denatured lysozyme for 1 min, and heat denatured lysozyme for 1 hour by real-time PCR.Significant differences were observed between distilled water and non-denatured lysozyme treatment(p < 0.05) and between non-denatured lysozyme treatment and heat denatured lysozyme treatment(p < 0.01).
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f4: Estimation of MNV-1 particles after exposed to distilled water, untreated lysozyme for 1 min, heat denatured lysozyme for 1 min, and heat denatured lysozyme for 1 hour by real-time PCR.Significant differences were observed between distilled water and non-denatured lysozyme treatment(p < 0.05) and between non-denatured lysozyme treatment and heat denatured lysozyme treatment(p < 0.01).

Mentions: Heat-treated and untreated lysozyme solutions were each mixed with MNV-1 to obtain a final concentration of 1%. Real-time PCR was used to measure the virus particle count (Fig. 4). As a result, the virus particle count in the virus samples exposed to the heated lysozyme for 1 min and 1 h were well below the detection limit of this real-time PCR assay.


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)

Estimation of MNV-1 particles after exposed to distilled water, untreated lysozyme for 1 min, heat denatured lysozyme for 1 min, and heat denatured lysozyme for 1 hour by real-time PCR.Significant differences were observed between distilled water and non-denatured lysozyme treatment(p < 0.05) and between non-denatured lysozyme treatment and heat denatured lysozyme treatment(p < 0.01).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f4: Estimation of MNV-1 particles after exposed to distilled water, untreated lysozyme for 1 min, heat denatured lysozyme for 1 min, and heat denatured lysozyme for 1 hour by real-time PCR.Significant differences were observed between distilled water and non-denatured lysozyme treatment(p < 0.05) and between non-denatured lysozyme treatment and heat denatured lysozyme treatment(p < 0.01).
Mentions: Heat-treated and untreated lysozyme solutions were each mixed with MNV-1 to obtain a final concentration of 1%. Real-time PCR was used to measure the virus particle count (Fig. 4). As a result, the virus particle count in the virus samples exposed to the heated lysozyme for 1 min and 1 h were well below the detection limit of this real-time PCR assay.

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