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54. Solid-state Thermal Transformation of Methylammonium Monomolybdate to Polyoxomolybdates and their Applications as Staining Reagents for Transmission Electron Microscopy Observations of Viruses

Author

Sukmana, Ndaru Candra, Shinogi, Jun, Kojima, Tatsuhiro, Higashiura, Akifumi, Yamamoto, Akima, Sakaguchi, Takemasa, and Sadakane, Masahiro

Abstract

The solid-state heating of methylammonium monomolybdate, (CH3NH3)2[MoO4] (prepared by dissolving MoO3in an aqueous methylamine solution), in air released methylamine and water to produce (CH3NH3)6[Mo7O24] and followed by (CH3NH3)8[Mo10O34] before transformation to MoO3. We report the first single-crystal X-ray structural analysis of (CH3NH3)2[MoO4] and (CH3NH3)6[Mo7O24] and demonstrate that the decamolybdate structure is different from that obtained from ammonium molybdates. Furthermore, (CH3NH3)6[Mo7O24] is a good negative staining reagent for transmission electron microscopy observations of viruses, such as SARS-CoV-2 and influenza virus.The release of methylamine and water while heating methylammonium monomolybdate results in the formation of two methylammonium polyoxomolybdates (CH3NH3)6[Mo7O24] and (CH3NH3)8[Mo10O34] before transformation to molybdenum oxides such as hexagonal MoO3and orthorhombic MoO3. Methylammonium heptamolybdate can be used as a negative staining reagents for transmission electron microscopy observation of SARS-CoV-2 and influenza viruses.

Published
2023
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55. Thermal Structure Transformation of Methylammonium Vanadate and it's Application as a Negative Staining Reagent for Observing SARS‐CoV‐2.

Author

Sukmana, Ndaru Candra, Sugiarto, Shinogi, Jun, Yamamoto, Akima, Higashiura, Akifumi, Sakaguchi, Takemasa, and Sadakane, Masahiro

Subjects
METHYLAMMONIUM, DIFFERENTIAL scanning calorimetry, SARS-CoV-2, TRANSMISSION electron microscopy, SPACE groups, SNAKE venom
Abstract

The solid‐state thermal structure transformation of methylammonium vanadate, (CH3NH3)VO3, from −150 °C to 350 °C is reported. Variable‐temperature X‐ray single‐crystal structure analysis at 23, 0, −50, −100, and −150 °C reveal (CH3NH3)VO3 comprises of methylammonium cations and "snake‐like" ([VO3]−)n anion chains propagating along the c‐direction in the Pna21 space group. In between −150 and −100 °C, we observe a reversible structural transformation due to the re‐orientation of the methylammonium cations in the crystal packing, which is also confirmed by the reversible profiles observed in differential scanning calorimetry. The methylammonium vanadate is stable until at ca. 100 °C and further heating releases methylamine and water and V2O5 is formed at ca. 275 °C. Furthermore, we show that the methylammonium vanadate can be used as a negative staining reagent for visualizing SARS‐CoV‐2, allowing us to discern the spike proteins from the body of the virus using transmission electron microscopy. [ABSTRACT FROM AUTHOR]

Published
2022
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56. Rosmarinic acid is a novel inhibitor for Hepatitis B virus replication targeting viral epsilon RNA-polymerase interaction

Author

TSUKAMOTO, Yuta, IKEDA, Sotaro, 1000080347905, UWAI, Koji, TAGUCHI, Riho, CHAYAMA, Kazuaki, SAKAGUCHI, Takemasa, NARITA, Ryo, YAO, Wan-Ling, TAKEUCHI, Fumihiko, OTAKAKI, Yukie, WATASHI, Koichi, WAKITA, Takaji, KATO, Hiroki, FUJITA, Takashi, TSUKAMOTO, Yuta, IKEDA, Sotaro, 1000080347905, UWAI, Koji, TAGUCHI, Riho, CHAYAMA, Kazuaki, SAKAGUCHI, Takemasa, NARITA, Ryo, YAO, Wan-Ling, TAKEUCHI, Fumihiko, OTAKAKI, Yukie, WATASHI, Koichi, WAKITA, Takaji, KATO, Hiroki, and FUJITA, Takashi

Abstract

Current therapeutics for hepatitis B virus (HBV) patients such as nucleoside analogs (NAs) are effective; however, new antiviral drugs against HBV are still desired. Since the interaction between the epsilon (c) sequence of HBV pregenomic RNA and viral polymerase (Pot) is a key step in the HBV replication cycle, we aimed to identify small compounds for its inhibition, and established a pull-down assay system for the detection of c-RNA-binding-Pol. Screening showed that 5 out of 3,965 compounds inhibited c-Pol binding, and we identified rosmarinic acid, which exhibited specificity, as a potential antiviral agent. In order to examine the anti-HBV effects of rosmarinic acid, HBV-infected primary human hepatocytes from a humanized mouse liver were treated with rosmarinic acid. The rosmarinic acid treatment decreased HBV components including the amounts of extracellular HBV DNA with negligible cytotoxicity. We also investigated the combined effects of rosmarinic acid and the NA, lamivudine. rosmarinic acid slightly enhanced the anti-HBV activity of lamivudine, suggesting that the HBV replication step targeted by rosmarinic acid is distinct from that of NA. We analyzed an additional 25 rosmarinic acid derivatives, and found that 5 also inhibited c-Pol. Structural comparisons between these derivatives implied that the "two phenolic hydroxyl groups at both ends" and the "caffeic acid-like structure" of rosmarinic acid are critical for the inhibition of c-Pol binding. Collectively, our results demonstrate that rosmarinic acid inhibits HBV replication in HBV-infected cells by specifically targeting c-Pol binding.

Published
2021

63. Molecular characterization and the mutation pattern of SARS-CoV-2 during first and second wave outbreaks in Hiroshima, Japan

Author

Ko, Ko, primary, Nagashima, Shintaro, additional, E., Bunthen, additional, Ouoba, Serge, additional, Akita, Tomoyuki, additional, Sugiyama, Aya, additional, Ohisa, Masayuki, additional, Sakaguchi, Takemasa, additional, Tahara, Hidetoshi, additional, Ohge, Hiroki, additional, Ohdan, Hideki, additional, Kubo, Tatsuhiko, additional, Kishita, Eisaku, additional, Kuwabara, Masao, additional, Takahashi, Kazuaki, additional, and Tanaka, Junko, additional

Published
2021
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72. Crystal structure of O‐ureidoserine racemase found in the d‐cycloserine biosynthetic pathway.

Author

Oda, Kosuke, Sakaguchi, Takemasa, and Matoba, Yasuyuki

Abstract

The O‐ureidoserine racemase (DcsC) is an enzyme found from the biosynthetic gene cluster of antitubercular agent d‐cycloserine. Although DcsC is homologous to diaminopimelate epimerase (DapF) that catalyzes the interconversion between ll‐ and dl‐diaminopimelic acid, it specifically catalyzes the interconversion between O‐ureido‐l‐serine and its enantiomer. Here we determined the crystal structure of DcsC at a resolution of 2.12 Å, implicating that the catalytic mechanism of DcsC shares similarity with that of DapF. Comparing the structure of the active center of DcsC to that of DapF, Thr72, Thr198, and Tyr219 of DcsC are likely to be involved in the substrate specificity. [ABSTRACT FROM AUTHOR]

Published
2022
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73. Sequential dynamics of virological and serological changes in the serum of SARS‐CoV‐2 infected patients.

Author

Ouoba, Serge, Okimoto, Mafumi, Nagashima, Shintaro, Kitahara, Yoshihiro, Miwata, Kei, Ko, Ko, E, Bunthen, Sugiyama, Aya, Takahashi, Kazuaki, Sakaguchi, Takemasa, Takafuta, Toshiro, and Tanaka, Junko

Subjects
SARS-CoV-2, CORONAVIRUS diseases, COVID-19, VIRAL antibodies
Abstract

Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) viral load dynamics in respiratory samples have been studied, but knowledge about changes in serial serum samples of infected patients in relation to their immunological response is lacking. We investigated the dynamics of SARS‐CoV‐2 viral load and antibody response in sequential serum of coronavirus disease 2019 (COVID‐19) patients and attempted to culture the virus in the serum. A total of 81 sequential serum samples from 10 confirmed COVID‐19 patients (5 with mild and 5 with moderate symptoms) were analyzed. Samples were collected during hospitalization and after discharge (median follow‐up of 35 days). SARS‐CoV‐2 ribonucleic acid in the serum was detected by real‐time polymerase chain reaction. Total antibody and IgG to SARS‐CoV‐2 Spike protein were analyzed by Chemiluminescent Immunoassays, and neutralizing antibodies were detected using a Surrogate Virus Neutralization Test. Viremia was observed in all cases at admission, and viral copy gradually dropped to undetectable levels in patients with mild symptoms but fluctuated and remained persistent in moderate cases. The viral culture of samples with the highest viral load for each patient did not show any cytopathic change. The antibody response was faster and higher in moderate cases. This study provides a basic clue for infectious severity‐dependent immune response, viremia, and antibody acquisition pattern. [ABSTRACT FROM AUTHOR]

Published
2022
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75. The ion channel activity of the influenza virus M2 protein affects transport through the Golgi apparatus

Author

Sakaguchi, Takemasa, Leser, George P., and Lamb, Robert A.

Subjects
Ion channels -- Research, Influenza viruses -- Physiological aspects, Golgi apparatus -- Research, Biological sciences
Abstract

The rate of intracellular transport of hemagglutinin (HA) and other membrane glycoproteins is inhibited by higher levels of expression of the M2 ion channel protein of the influenza virus. HA coexpressed with M2 properly folded and trimerizes with the same kinetics as when HA is expressed alone. The Golgi transport delay is due to the M2 protein ion channel activity maintaining pH between the Golgi lumen and the cytoplasm. There is some similarity of effects of M2 ion channel activity and monensin on transport through the Golgi apparatus.

Published
1996

83. Inactivation of the Influenza Virus by a Supplemental Fermented Plant Product (Manda Koso)

Author

Nomura, Toshihito, Yoshimoto, Reiko, Kawabata, Ryoko, Matsubara, Toshiki, Narai, Seika, Oda, Kosuke, Fukushi, Masaya, Irie, Takashi, and Sakaguchi, Takemasa

Subjects
viruses, anti-viral reagents, feline calicivirus, virus diseases, cytotoxicity, influenza virus
Abstract

Manda Koso is a commercial fermented plant product (FPP) made from 53 types of fruits and vegetables that are fermented for more than 3 years. We hypothesized that the FPP can prevent infection by influenza virus and human norovirus. Therefore, we investigated the effects of the FPP on influenza virus and feline calicivirus, a surrogate of human norovirus. We found that 10% FPP inactivated the influenza virus but not the feline calicivirus. Inhibition of the influenza virus was highly concentration-dependent: 1% and 0.3% FPP showed reduced inactivation efficacy. The effects of the FPP on the influenza virus-infected cells were investigated by addition of the FPP to the culture medium after virus infection. No suppressive effect of the FPP on influenza replication in MDCK cells was observed. The results showed that the FPP could inactivate influenza virus by affecting the virus particles.

Published
2017

86. Rosmarinic acid is a novel inhibitor for Hepatitis B virus replication targeting viral epsilon RNA-polymerase interaction

Author

Tsukamoto, Yuta, primary, Ikeda, Sotaro, additional, Uwai, Koji, additional, Taguchi, Riho, additional, Chayama, Kazuaki, additional, Sakaguchi, Takemasa, additional, Narita, Ryo, additional, Yao, Wan-Ling, additional, Takeuchi, Fumihiko, additional, Otakaki, Yukie, additional, Watashi, Koichi, additional, Wakita, Takaji, additional, Kato, Hiroki, additional, and Fujita, Takashi, additional

Published
2018
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89. Rosmarinic acid is a novel inhibitor for Hepatitis B virus replication targeting viral epsilon RNA-polymerase interaction

Author

20852437, Tsukamoto, Yuta, Ikeda, Sotaro, Uwai, Koji, Taguchi, Riho, Chayama, Kazuaki, Sakaguchi, Takemasa, Narita, Ryo, Yao, Wan-Ling, Takeuchi, Fumihiko, Otakaki, Yukie, Watashi, Koichi, Wakita, Takaji, Kato, Hiroki, Fujita, Takashi, 20852437, Tsukamoto, Yuta, Ikeda, Sotaro, Uwai, Koji, Taguchi, Riho, Chayama, Kazuaki, Sakaguchi, Takemasa, Narita, Ryo, Yao, Wan-Ling, Takeuchi, Fumihiko, Otakaki, Yukie, Watashi, Koichi, Wakita, Takaji, Kato, Hiroki, and Fujita, Takashi

Published
2018

90. Rosmarinic acid is a novel inhibitor for Hepatitis B virus replication targeting viral epsilon RNA-polymerase interaction

Author

TSUKAMOTO Yuta, IKEDA Sotaro, UWAI Koji, TAGUCHI Riho, CHAYAMA Kazuaki, SAKAGUCHI Takemasa, NARITA Ryo, YAO Wan-Ling, TAKEUCHI Fumihiko, OTAKAKI Yukie, WATASHI Koichi, WAKITA Takaji, KATO Hiroki, FUJITA Takashi, TSUKAMOTO Yuta, IKEDA Sotaro, UWAI Koji, TAGUCHI Riho, CHAYAMA Kazuaki, SAKAGUCHI Takemasa, NARITA Ryo, YAO Wan-Ling, TAKEUCHI Fumihiko, OTAKAKI Yukie, WATASHI Koichi, WAKITA Takaji, KATO Hiroki, and FUJITA Takashi

Abstract

Current therapeutics for hepatitis B virus (HBV) patients such as nucleoside analogs (NAs) are effective; however, new antiviral drugs against HBV are still desired. Since the interaction between the epsilon (c) sequence of HBV pregenomic RNA and viral polymerase (Pot) is a key step in the HBV replication cycle, we aimed to identify small compounds for its inhibition, and established a pull-down assay system for the detection of c-RNA-binding-Pol. Screening showed that 5 out of 3,965 compounds inhibited c-Pol binding, and we identified rosmarinic acid, which exhibited specificity, as a potential antiviral agent. In order to examine the anti-HBV effects of rosmarinic acid, HBV-infected primary human hepatocytes from a humanized mouse liver were treated with rosmarinic acid. The rosmarinic acid treatment decreased HBV components including the amounts of extracellular HBV DNA with negligible cytotoxicity. We also investigated the combined effects of rosmarinic acid and the NA, lamivudine. rosmarinic acid slightly enhanced the anti-HBV activity of lamivudine, suggesting that the HBV replication step targeted by rosmarinic acid is distinct from that of NA. We analyzed an additional 25 rosmarinic acid derivatives, and found that 5 also inhibited c-Pol. Structural comparisons between these derivatives implied that the "two phenolic hydroxyl groups at both ends" and the "caffeic acid-like structure" of rosmarinic acid are critical for the inhibition of c-Pol binding. Collectively, our results demonstrate that rosmarinic acid inhibits HBV replication in HBV-infected cells by specifically targeting c-Pol binding.

Published
2018

93. Inhibition of Virus-like Particle Release of Sendai virus and Nipah virus, but not that of Mumps virus, by Tetherin/CD317/BST-2

Author

Kong, Weng-Sheng, Irie, Takashi, Yoshida, Asuka, Kawabata, Ryoko, Kadoi, Takahiro, and Sakaguchi, Takemasa

Subjects
Paramyxovirus, Mumps virus, viruses, virus diseases, Tetherin/CD317/BST-2, Nipah virus, biochemical phenomena, metabolism, and nutrition, Sendai virus
Abstract

Tetherin (also known as BST-2 or CD317) has recently been identified as a potent IFN-induced anti-viral protein that inhibits the release of diverse enveloped virus particles from infected cells. The anti-viral activity of tetherin on a number of enveloped viruses, including retroviruses, filoviruses and arenaviruses, has been examined. Here, we show that tetherin is also capable of blocking the release of virus-like particles (VLPs) driven by the matrix protein of Sendai virus. Together with inhibition of Nipah virus VLP release by tetherin, these results indicate that paramyxoviruses are to be added to the list of viruses that are susceptible to tetherin inhibition. Tetherin co-localized with Nipah virus matrix proteins and accumulated in cells, indicating that it is present at, or recruited to, sites of particle assembly. It should be noted, however, that tetherin was not effective against the release of paramyxovirus mumps VLPs, indicating that certain enveloped viruses may not be sensitive to tetherin activity.

Published
2012

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