Browsing by Author "Ergunay, Koray"

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Characterization of local SARS-CoV-2 isolates and pathogenicity in IFNAR(-/-) mice
(2020) Hanifehnezhad, Alireza; Kehribar, Ebru Sahin; Oztop, Sidika; Sheraz, Ali; Kasirga, Serkan; Ergunay, Koray; Onder, Sevgen; Yilmaz, Erkan; Engin, Doruk; Oguzoglu, T. Cigdem; Seker, Urartu Ozgur Safak; Yilmaz, Engin; Ozkul, Aykut; 0000-0001-5653-6080; 33015402; AAJ-7911-2020
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) recently a global pandemic with unprecedented public health, economic and social impact. The development of effective mitigation strategies, therapeutics and vaccines relies on detailed genomic and biological characterization of the regional viruses. This study was carried out to isolate SARS-CoV-2 viruses circulating in Anatolia, and to investigate virus propagation in frequently-used cells and experimental animals. We obtained two SARS-CoV-2 viruses from nasopharngeal swabs of confirmed cases in Vero E6 cells, visualized the virions using atomic force and scanning electron microscopy and determined size distribution of the particles. Viral cytopathic effects on Vero E6 cells were initially observed at 72 h post-inoculation and reached 90% of the cells on the 5th day. The isolates displayed with similar infectivity titers, time course and infectious progeny yields. Genome sequencing revealed the viruses to be well-conserved, with less than 1% diversity compared to the prototype virus. The analysis of the viral genomes, along with the available 62 complete genomes from Anatolia, showed limited diversity (up to 0.2% on deduced amino acids) and no evidence of recombination. The most prominent sequence variation was observed on the spike protein, resulting in the substitution D614G, with a prevalence of 56.2%. The isolates produced non-fatal infection in the transgenic type I interferon knockout (IFNAR(-/-)) mice, with varying neutralizing antibody titers. Hyperemia, regional consolidation and subpleural air accumulation was observed on necropsy, with similar histopathological and immunohistochemistry findings in the lungs, heart, stomach, intestines, liver, spleen and kidneys. Peak viral loads were detected in the lungs, with virus RNA present in the kidneys, jejunum, liver, spleen and heart. In conclusion, we characterized two local isolates, investigated in vitro growth dynamics in Vero E6 cells and identified IFNAR-/- mice as a potential animal model for SARS-CoV-2 experiments.
A Highly Potent SARS-CoV-2 Blocking Lectin Protein
(2022) Ahan, Recep E.; Hanifehnezhad, Alireza; Kehribar, Ebru S.; Oguzoglu, Tuba C.; Foldes, Katalin; Ozcelik, Cemile E.; Filazi, Nazlican; Oztop, Sidika; Palaz, Fahreddin; Onder, Sevgen; Bozkurt, Eray U.; Ergunay, Koray; Ozkul, Aykut; Seker, Urartu Ozgur Safak; https://orcid.org/0000-0001-5653-6080; 35426678; AAJ-7911-2020
The COVID-19 (coronavirus disease-19) pandemic affected more than 180 million people around the globe, causing more than five million deaths as of January 2022. SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), the new coronavirus, has been identified as the primary cause of the infection. The number of vaccinated people is increasing; however, prophylactic drugs are highly demanded to ensure secure social contact. A number of drug molecules have been repurposed to fight against SARS-CoV-2, and some of them have been proven to be effective in preventing hospitalization or ICU admissions. Here, we demonstrated griffithsin (GRFT), a lectin protein, to block the entry of SARS-CoV-2 and its variants, Delta and Omicron, into the Vero E6 cell lines and IFNAR(-/-) mouse models by attaching to the spike protein of SARS-CoV-2. Given the current mutation frequency of SARS-CoV-2, we believe that GRFT protein-based drugs will have a high impact in preventing the transmission of both the Wuhan strain as well as any other emerging variants, including Delta and Omicron variants, causing the high-speed spread of COVID-19.
Multi-assay investigation of viral etiology in pediatric central nervous system infections
(2020) Altay-Kocak, Aylin; Bozdayi, Gulendam; Michel, Janine; Polat, Meltem; Kanik-Yuksek, Saliha; Tezer, Hasan; Ozkul, Aykut; Ahmed, Kamruddin; Nitsche, Andreas; Ergunay, Koray; 32683347
Introduction: In an attempt to identify a wide spectrum of viral infections, cerebrospinal fluid (CSF) specimens were collected from pediatric cases with the preliminary diagnosis of viral encephalitis/meningoencephalitis in two reference hospitals, from October 2011 to December 2015. Methodology: A combination of nucleic acid-based assays, including in house generic polymerase chain reaction (PCR) assays for enteroviruses, flaviviruses and phleboviruses, a commercial real-time PCR assay for herpesviruses and a commercial real time multiplex PCR, enabling detection of frequently-observed viral, bacterial and fungal agents were employed for screening. Results: The microbial agent could be characterized in 10 (10%) of the 100 specimens. Viral etiology could be demonstrated in 7 (70%) specimens, which comprises Human Herpesvirus 6 (4/7), Herpes Simplex virus type1 (2/7) and Enteroviruses (1/7). In 3 specimens (30%), Streptococcus pneumoniae, Listeria monocytogenes and Staphylococcus aureus were detected via the multiplex PCR, which were also isolated in bacteriological media. All specimens with detectable viral nucleic acids, as well as unreactive specimens via nucleic acid testing remained negative in bacteriological cultures. Conclusions: Herpes and enteroviruses were identified as the primary causative agents of central nervous system infections in children. Enterovirus testing must be included in the diagnostic work-up of relevant cases.