The ongoing outbreak of COVID-19 that began in Wuhan, China, has constituted a Public Health Emergency of International Concern, with cases confirmed in multiple countries. Currently, patients are the primary source of infection. We report a confirmed case of COVID-19 whose oropharyngeal swab test of SARS-CoV-2 RNA turned positive in convalescence. This case highlights the importance of active surveillance of SARS-CoV-2 RNA for infectivity assessment.
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http://dx.doi.org/10.1016/j.ijid.2020.03.003 | DOI Listing |
Nucleic Acids Res
January 2025
Single-Molecule and Cell Mechanobiology Laboratory, Daejeon, 34141, South Korea.
Helicase is a nucleic acid motor that catalyses the unwinding of double-stranded (ds) RNA and DNA via ATP hydrolysis. Helicases can act either as a nucleic acid motor that unwinds its ds substrates or as a chaperone that alters the stability of its substrates, but the two activities have not yet been reported to act simultaneously. Here, we used single-molecule techniques to unravel the synergistic coordination of helicase and chaperone activities, and found that the severe acute respiratory syndrome coronavirus helicase (nsp13) is capable of two modes of action: (i) binding of nsp13 in tandem with the fork junction of the substrate mechanically unwinds the substrate by an ATP-driven synchronous power stroke; and (ii) free nsp13, which is not bound to the substrate but complexed with ADP in solution, destabilizes the substrate through collisions between transient binding and unbinding events with unprecedented melting capability.
View Article and Find Full Text PDFMikrobiyol Bul
January 2025
Kocaeli Üniversitesi Tıp Fakültesi, Tıbbi Mikrobiyoloji Anabilim Dalı, Kocaeli.
Son yıllarda pandemi nedeniyle virüslerin tanı ve tedavisine yönelik terapötik yöntemlerin geliştirilmesi ve antivirallerin test edilmesi amacıyla çok sayıda in vitro çalışma yapılmaktadır. Literatürde SARS-CoV-2'nin modellenebilmesi için HCoV-229E'nin kullanımının güvenli ve yeterli olup olmadığını inceleyen çalışmalar sınırlıdır. Bu sebeple bu çalışmada, BSL-2 şartlarında gerçekleştirilebilen HCoV-229E kültürü ve kantitasyon çalışmalarının, BSL-3 şartları gerektiren SARS-CoV-2 deneylerinde bir ön çalışma modeli olup olamayacağının antiviral etkinlik analizleri üzerinden araştırılması amaçlanmıştır.
View Article and Find Full Text PDFActa Naturae
January 2024
Lomonosov Moscow State University, Faculty of Biology, Moscow, 119234 Russian Federation.
Analytical electron microscopy techniques, including energy-dispersive X-ray spectroscopy (EDX) and electron energy-loss spectroscopy (EELS), are employed in materials science and biology to visualize and chemically map diverse elements. This review presents cases of successful identification of nucleic acids in cells and in DNA- and RNA-containing viruses that use the chemical element phosphorus as a marker.
View Article and Find Full Text PDFPLoS One
January 2025
Department of Pharmacology & Toxicology, The University of Texas Medical Branch, Galveston, Texas, United States of America.
Severe acute respiratory syndrome coronavirus-1 (SARS-CoV-1) and -2 (SARS-CoV-2) are beta-coronaviruses (β-CoVs) that have caused significant morbidity and mortality worldwide. Therefore, a better understanding of host responses to β-CoVs would provide insights into the pathogenesis of these viruses to identify potential targets for medical countermeasures. In this study, our objective is to use a systems biology approach to explore the magnitude and scope of innate immune responses triggered by SARS-CoV-1 and -2 infection over time in pathologically relevant human lung epithelial cells (Calu-3/2B4 cells).
View Article and Find Full Text PDFJ Cachexia Sarcopenia Muscle
February 2025
Meakins-Christie Laboratories and Translational Research in Respiratory Diseases Program, Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada.
Background: COVID-19 has been associated with both respiratory (diaphragm) and non-respiratory (limb) muscle atrophy. It is unclear if SARS-CoV-2 infection of skeletal muscle plays a role in these changes. This study sought to: 1) determine if cells comprising skeletal muscle tissue, particularly myofibres, express the molecular components required for SARS-CoV-2 infection; 2) assess the capacity for direct SARS-CoV-2 infection and its impact on atrophy pathway genes in myogenic cells; and 3) in an animal model of COVID-19, examine the relationship between viral infection of skeletal muscle and myofibre atrophy within the diaphragm and limb muscles.
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