Abstract P-37: Phosphorous Mapping in Inactivated SARS-Cov-2 Particles by Electron Energy Loss Spectroscopy

Background: The severe COVID-19 pandemic started in December 2019 is caused by the SARS-CoV-2 virus. The SARS-CoV-2 virion consists of a positive-sense single-stranded RNA (ssRNA), bound with the nucleocapsid N protein and surrounded by a lipid membrane with the embedded glycoprotein S and the trans...

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Main Authors: Andrey Moiseenko, Lubov Kozlovskaya, Aydar Ishmukhametov, Alexey Egorov, Konstantin Shaitan, Mikhail Kirpichnikov, Olga Sokolova
Format: Article
Language:English
Published: International Medical Research and Development Corporation 2021-06-01
Series:International Journal of Biomedicine
Subjects:
Online Access:http://ijbm.org/articles/v11s1/ijbm_2021_11_s1_p37.pdf
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author Andrey Moiseenko
Lubov Kozlovskaya
Aydar Ishmukhametov
Alexey Egorov
Konstantin Shaitan
Mikhail Kirpichnikov
Olga Sokolova
author_facet Andrey Moiseenko
Lubov Kozlovskaya
Aydar Ishmukhametov
Alexey Egorov
Konstantin Shaitan
Mikhail Kirpichnikov
Olga Sokolova
author_sort Andrey Moiseenko
collection DOAJ
description Background: The severe COVID-19 pandemic started in December 2019 is caused by the SARS-CoV-2 virus. The SARS-CoV-2 virion consists of a positive-sense single-stranded RNA (ssRNA), bound with the nucleocapsid N protein and surrounded by a lipid membrane with the embedded glycoprotein S and the transmembrane proteins M and E. The structure of inactivated SARS-CoV-2 virions is crucial for the development of vaccine-induced immunity. Here we characterized the nucleic acid distribution within β-propiolactone inactivated whole-virion SARS-CoV-2 vaccine CoviVac. Methods: We used EELS to verify the presence of phosphorus (P) inside the β-propiolactone inactivated virions. Electron microscopy was performed with a JEM-2100 200kV LaB6 transmission electron microscope (JEOL, Japan) equipped with a Gatan GIF Quantum ER energy filter (Gatan, USA) operating in spectrometer mode, along with a High-Angle Annular Dark-Field (HAADF) scanning transmission electron microscopy (STEM) detector. The cooling holder model 21090 (JEOL, Japan) was operated at -182 °С to reduce the contamination effects and to enhance the specimen's stability under the electron beam. We employ a negative stain with 2% (NH4)2MoO4 rather than uranyl acetate since the Uranium O4,5 peak (edge at 96 eV) is close to the P L2,3 peak (edge at 132 eV) and interferes with the accurate background interpolation. Results: The intensity under the P peak after the background subtraction was used for STEM-EELS mapping. We observed the characteristic P signal from the inner part of the virion but not from the bare grid. The observed P signal could arise from either viral RNA or lipids of the virus membrane, and since the P signal is highly heterogeneous, it is more likely to originate from RNA. Conclusion: So far, phosphorous mapping in individual virions using EELS was done only with samples prepared using highly specialized techniques, which minimized the sample thickness, including the substrate thickness. Here, we performed elemental mapping on ordinary samples of whole viruses. All investigated virions contained P signal, but its spatial distribution and intensity differed significantly. This clearly reflects the non-even distribution of the genomic RNA, which, apparently, accompanies their inner heterogeneity, previously observed by in-situ cryo-electron tomography.
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spelling doaj.art-9956aa62b6b04462a2eeb57012ec68ce2022-12-21T20:08:51ZengInternational Medical Research and Development CorporationInternational Journal of Biomedicine2158-05102158-05292021-06-0111Suppl_1282810.21103/IJBM.11.Suppl_1.P37Abstract P-37: Phosphorous Mapping in Inactivated SARS-Cov-2 Particles by Electron Energy Loss SpectroscopyAndrey Moiseenko0Lubov Kozlovskaya1Aydar Ishmukhametov2Alexey Egorov3Konstantin Shaitan4Mikhail Kirpichnikov5Olga Sokolova6Lomonosov Moscow State University, Moscow, RussiaChumakov Federal Scientific Center Research and Development of Immune and Biological Product of Russian Academy of Sciences, Moscow, RussiaChumakov Federal Scientific Center Research and Development of Immune and Biological Product of Russian Academy of Sciences, Moscow, RussiaLomonosov Moscow State University, Moscow, Russia; N.N.Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, Moscow, RussiaLomonosov Moscow State University, Moscow, Russia; N.N.Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, Moscow, RussiaLomonosov Moscow State University, Moscow, RussiaLomonosov Moscow State University, Moscow, RussiaBackground: The severe COVID-19 pandemic started in December 2019 is caused by the SARS-CoV-2 virus. The SARS-CoV-2 virion consists of a positive-sense single-stranded RNA (ssRNA), bound with the nucleocapsid N protein and surrounded by a lipid membrane with the embedded glycoprotein S and the transmembrane proteins M and E. The structure of inactivated SARS-CoV-2 virions is crucial for the development of vaccine-induced immunity. Here we characterized the nucleic acid distribution within β-propiolactone inactivated whole-virion SARS-CoV-2 vaccine CoviVac. Methods: We used EELS to verify the presence of phosphorus (P) inside the β-propiolactone inactivated virions. Electron microscopy was performed with a JEM-2100 200kV LaB6 transmission electron microscope (JEOL, Japan) equipped with a Gatan GIF Quantum ER energy filter (Gatan, USA) operating in spectrometer mode, along with a High-Angle Annular Dark-Field (HAADF) scanning transmission electron microscopy (STEM) detector. The cooling holder model 21090 (JEOL, Japan) was operated at -182 °С to reduce the contamination effects and to enhance the specimen's stability under the electron beam. We employ a negative stain with 2% (NH4)2MoO4 rather than uranyl acetate since the Uranium O4,5 peak (edge at 96 eV) is close to the P L2,3 peak (edge at 132 eV) and interferes with the accurate background interpolation. Results: The intensity under the P peak after the background subtraction was used for STEM-EELS mapping. We observed the characteristic P signal from the inner part of the virion but not from the bare grid. The observed P signal could arise from either viral RNA or lipids of the virus membrane, and since the P signal is highly heterogeneous, it is more likely to originate from RNA. Conclusion: So far, phosphorous mapping in individual virions using EELS was done only with samples prepared using highly specialized techniques, which minimized the sample thickness, including the substrate thickness. Here, we performed elemental mapping on ordinary samples of whole viruses. All investigated virions contained P signal, but its spatial distribution and intensity differed significantly. This clearly reflects the non-even distribution of the genomic RNA, which, apparently, accompanies their inner heterogeneity, previously observed by in-situ cryo-electron tomography.http://ijbm.org/articles/v11s1/ijbm_2021_11_s1_p37.pdfcovid-19β-propiolactone inactivated virus particleseelsnucleocapsid
spellingShingle Andrey Moiseenko
Lubov Kozlovskaya
Aydar Ishmukhametov
Alexey Egorov
Konstantin Shaitan
Mikhail Kirpichnikov
Olga Sokolova
Abstract P-37: Phosphorous Mapping in Inactivated SARS-Cov-2 Particles by Electron Energy Loss Spectroscopy
International Journal of Biomedicine
covid-19
β-propiolactone inactivated virus particles
eels
nucleocapsid
title Abstract P-37: Phosphorous Mapping in Inactivated SARS-Cov-2 Particles by Electron Energy Loss Spectroscopy
title_full Abstract P-37: Phosphorous Mapping in Inactivated SARS-Cov-2 Particles by Electron Energy Loss Spectroscopy
title_fullStr Abstract P-37: Phosphorous Mapping in Inactivated SARS-Cov-2 Particles by Electron Energy Loss Spectroscopy
title_full_unstemmed Abstract P-37: Phosphorous Mapping in Inactivated SARS-Cov-2 Particles by Electron Energy Loss Spectroscopy
title_short Abstract P-37: Phosphorous Mapping in Inactivated SARS-Cov-2 Particles by Electron Energy Loss Spectroscopy
title_sort abstract p 37 phosphorous mapping in inactivated sars cov 2 particles by electron energy loss spectroscopy
topic covid-19
β-propiolactone inactivated virus particles
eels
nucleocapsid
url http://ijbm.org/articles/v11s1/ijbm_2021_11_s1_p37.pdf
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