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Efficient and quick inactivation of SARS coronavirus and other microbes exposed to the surfaces of some metal catalysts

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Abstract

To study the two metal catalysts Ag/Al2O3 and Cu/Al2O3 that interdict the transmission pathway for SARS and other respiratory infectious diseases. Two metal catalysts Ag/Al2O3 and Cu/Al2O3 were pressed into wafers. One hundred microL 10(6) TCID50/mL SARS-CoV, 100 microL 10(6) PFU/mL recombinant baculovirus expressing hamster's prion protein (haPrP) protein and roughly 10(6) E. coli were slowly dropped onto the surfaces of the catalyst wafers and exposed for 5 and 20 min, respectively. After eluted from the surfaces of wafers, the infectivity of viruses and propagation of bacteria were measured. The expression of PrP protein was determined by Western blot. The morphological changes of bacteria were observed by electronic microscopy. After exposure to the catalysts surfaces for 5 and 20 min, the infectivity of SARS-CoV in Vero cells and baculovirus in Sf9 cells dropped down to a very low and undetectable level, and no colony was detected using bacteria culture method. The expression of haPrP protein reduced to 21.8% in the preparation of Sf9 cells infected with recombinant baculovirus exposed for 5 min and was undetectable exposed for 20 min. Bacterial membranes seemed to be cracked and the cytoplasm seemed to be effluent from cell bodies. Exposures to the surfaces of Ag/Al2O3 and Cu/Al2O3 destroy the replication and propagation abilities of SARS-CoV, baculovirus and E. coli. Inactivation ability of metal catalysts needs to interact with air, utilizing oxygen molecules in air. Efficiently killing viruses and bacteria on the surfaces of the two metal catalysts has a promising potential for air-disinfection in hospitals, communities, and households.
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An idea of the chemical reconstruction caused by the formation of quasi-compounds and their self-assembly is defined. New surfaces were fabricated by combining the reaction of the quasi-compounds and their self-assembly. A quasi-compound of (CuO) strings was grown in the [11̄0] direction on Ag(110) by the reaction of (AgO) strings with Cu atoms, which brought about a reversible reaction of (CuO)⇄(Cu)6+O2. By the reaction of (AgO) strings with CO2, a composite structure of (AgO) and (AgCO3) was established on the Ag(110) surface. When Cu atoms were vaporized on this composite surface, the (AgO) strings reacted selectively with Cu atoms, and (CuO) strings grew in the [11̄0] direction. Interestingly, an opposite selective reaction occurred when the composite surface was scanned with a W tip coated with Cu; that is, Cu atoms react selectively with carbonate species. These phenomena suggest that the chemical reaction and the chemical transportation reaction will make realize atomic scale surface fabrication possible. The photochemical reaction of a quasi-compound was also attained on a composite surface of (AgO) and (Ag2N) strings on the Ag(110) surface, where the (AgO) strings were selectively erased by illumination.
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Conversion of the PrP cellular form (PrP(C)) to the pathogenic form (PrP(Sc)) is the key step in the pathogenesis of transmissible spongiform encephalophathies. Although the mechanism of conformational conversion of PrP proteins remains uncertain, the cell-free conversion reaction and other in vitro PrP amplification tests allow it to be studied under the much quicker and simpler conditions than those of transmission bioassay in vivo. Using baculovirus expression system, wild-type hamster (HaPrP) and human PrP (HuPrP), as well as D178N mutated human PrP (HuPrPm178) were expressed in HIS-fusion form. After 35S-methionine labeling and purification with Ni-NTA agarose affinity chromatography, individual expressed PrP proteins were mixed with PrP(Sc) isolated from hamster brain tissue infected with scrapie 263K. Protease-resistant isoform was detected in the homologous HaPrP reaction, but not in the two heterologous HuPrP preparations, implying a species-specific molecular recognition between PrP(C) and PrP(Sc). HIS-tag in HIS-HaPrP seems to have little effect on the formation of protease-resistant protein in this preparation. This system proposes a simple and protein productive-enriched way for cell-free conversion of prion proteins, as the replacement of native or genetic engineering expressed sole PrP(C) from mammalian or non-mammalian sources.
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An outbreak of severe acute respiratory syndrome (SARS) has been reported in Hong Kong. We investigated the viral cause and clinical presentation among 50 patients. We analysed case notes and microbiological findings for 50 patients with SARS, representing more than five separate epidemiologically linked transmission clusters. We defined the clinical presentation and risk factors associated with severe disease and investigated the causal agents by chest radiography and laboratory testing of nasopharyngeal aspirates and sera samples. We compared the laboratory findings with those submitted for microbiological investigation of other diseases from patients whose identity was masked. Patients' age ranged from 23 to 74 years. Fever, chills, myalgia, and cough were the most frequent complaints. When compared with chest radiographic changes, respiratory symptoms and auscultatory findings were disproportionally mild. Patients who were household contacts of other infected people and had older age, lymphopenia, and liver dysfunction were associated with severe disease. A virus belonging to the family Coronaviridae was isolated from two patients. By use of serological and reverse-transcriptase PCR specific for this virus, 45 of 50 patients with SARS, but no controls, had evidence of infection with this virus. A coronavirus was isolated from patients with SARS that might be the primary agent associated with this disease. Serological and molecular tests specific for the virus permitted a definitive laboratory diagnosis to be made and allowed further investigation to define whether other cofactors play a part in disease progression.
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Ralph A. Tripp, Lia M. Haynes, Deborah Moore, Barbara Anderson, Azaibi Tamin, Brian H. Harcourt, Les P. Jones, Mamadi Yilla, Gregory J. Babcock, Thomas Greenough, Donna M. Ambrosino, Rene Alvarez, Justin Callaway, Sheana Cavitt, Kurt Kamrud, Harold Alterson, Jonathan Smith, Jennifer L. Harcourt, Congrong Miao, Raj Razdan, James A. Comer, Pierre E. Rollin, Thomas G. Ksiazek, Anthony Sanchez, Paul A. Rota, William J. Bellini, Larry J. Anderson. (2005) Monoclonal antibodies to SARS-associated coronavirus (SARS-CoV): Identification of neutralizing and antibodies reactive to S, N, M and E viral proteins. Journal of Virological Methods 128, 21-28 CrossRef