RESUMO
There is a potential risk for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spread through human contact with seafood and the inanimate materials contaminated by the virus. In this study, we examined the stability of the virus in artificial seawater (ASW) and on the surface of selected materials. SARS-CoV-2 (3.75 log10 TCID50 ) in ASW at 22â maintained infectious about 3 days and at 4â the virus survived more than 7 days. It should be noticed that viable virus at high titer (5.50 log10 TCID50 ) may survive more than 20 days in ASW at 4â and for 7 days at 22â. SARS-CoV-2 on stainless steel and plastic bag maintained infectious for 3 days, and on nonwoven fabric for 1 day at 22â. In addition, the virus remained infectious for 9 days on stainless steel and non-woven fabric, and on plastic bag for 12 days at 4â. It is important to highlight the role of inanimate material surfaces as a source of infection and the necessity for surface decontamination and disinfection.
Assuntos
COVID-19 , SARS-CoV-2 , Humanos , Plásticos , Água do Mar , Aço InoxidávelRESUMO
OBJECTIVE: To clone Streptococcus salivarius (Ss) 57. I urease gene, which can express ureolytic activity in Escherichia coli (Ec) without adding extra nickel ions. METHODS: Urease gene was cloned by polymerase chain reaction in three separate parts. The three separate plasmids were digested by specific restriction enzymes and ligated together. The expression of the complete urease gene in Ec was detected by phenol red assay and pH analysis. RESULTS: Urease gene of Ss 57.I was eventually cloned and proved correct. Urease activity of the obtained clone was positive in Ec. Without adding extra NiCl(2), the recombinant Ec could hydrolyze urea to produce ammonia, resulting in the increase of pH value. CONCLUSIONS: The clone of Ss urease gene obtained in this study could express ureolytic activity in Ec without adding extra nickel ions. The current clone can be used to construct ureolytic effector strain used in replacement therapy in caries prevention.