Електрофізичні властивості системи політетрафторетилен – вуглецеві нанотрубки

Проведено дослідження комплексної діелектричної проникності та електропровідності в надвисокочастотному діапазоні (9 ГГц) і на низьких частотах (0,1; 1 та 10 кГц) двох систем політетрафторетилен – багатошарові вуглецеві нанотрубки з вихідними та диспергованими у водному середовищі . Введення диспергованих нанотрубок в полімер знижує поріг перколяції з 4,5 % до 2,6 % (мас.) за рахунок рівномірного розподілу наповнювача у полімері, що призводить до зростання міжфазної поверхні взаємодії полімер – вуглецеві нанотрубки, яка проявляється в збільшенні значень дійсної та уявної складової комплексної діелектричної проникності.Проведены исследования комплексной диэлектрической проницаемости и электропроводности в сверхвысокочастотном диапазоне (9 ГГц) и на низких частотах (0,1; 1; 10 кГц) двух систем политетрафторэтилен–многослойные углеродные нанотрубки с исходными и диспергированными у водной среде. Введение диспергированных нанотрубок в полимер снижает порог перколяции с 4,5% до 2,6 % (масс.) за счет равномерного распределения наполнителя в полимере, что приводит к возрастанию межфазной поверхности взаимодействия полимер – углеродные нанотрубки, которая проявляется в увеличении значений действительной и мнимой составляющей комплексной диэлектрической проницаемости.Complex dielectric permeability and conductivity of two systems, namely polytetrafluorethylene – intact carbon nanotubes and polytetrafluorethylene – carbon nanotubes dispersed in aqueous media, has been studied in super high-frequency range (9 GHz) and at low frequencies (0,1; 1 and 10 kHz). Doping of the polymer with the dispersed nanotubes decreases percolation threshold (limit ) from 4,5 wt. % to 2,6 wt. % due to uniform distribution of the filler in the polymer. This results to increase of interface interaction polymer - carbon nanotubes that is demonstrated by increase of value of real and imaginary component of complex dielectric permeability

A human monoclonal antibody blocking SARS-CoV-2 infection

The emergence of the novel human coronavirus SARS-CoV-2 in Wuhan, China has caused a worldwide epidemic of respiratory disease (COVID-19). Vaccines and targeted therapeutics for treatment of this disease are currently lacking. Here we report a human monoclonal antibody that neutralizes SARS-CoV-2 (and SARS-CoV) in cell culture. This cross-neutralizing antibody targets a communal epitope on these viruses and may offer potential for prevention and treatment of COVID-19

The receptor binding domain of the new middle east respiratory syndrome coronavirus maps to a 231-residue region in the spike protein that efficiently elicits neutralizing antibodies

The spike (S) protein of the recently emerged human Middle East respiratory syndromecoronavirus (MERS-CoV) mediates infection by binding to the cellular receptor dipeptidyl peptidase 4 (DPP4). Here we mapped the receptor binding domain in the S protein to a 231-amino-acid fragment (residues 358 to 588) by evaluating the interaction of spike truncation variants with receptor-expressing cells and soluble DPP4. Antibodies to this domain-mch less so those to the preceding N-terminal region-efficiently neutralize MERS-CoV infection

ATP1A1-mediated Src signaling inhibits coronavirus entry into host cells

In addition to transporting ions, the multisubunit Na+,K+-ATPase also functions by relaying cardiotonic steroid (CTS)-binding- induced signals into cells. In this study, we analyzed the role of Na+,K+-ATPase and, in particular, of its ATP1A1 α subunit during coronavirus (CoV) infection. As controls, the vesicular stomatitis virus (VSV) and influenza A virus (IAV) were included. Using gene silencing, the ATP1A1 protein was shown to be critical for infection of cells with murine hepatitis virus (MHV), feline infectious peritonitis virus (FIPV), and VSV but not with IAV. Lack of ATP1A1 did not affect virus binding to host cells but resulted in inhibited entry of MHV and VSV. Consistently, nanomolar concentrations of the cardiotonic steroids ouabain and bufalin, which are known not to affect the transport function of Na+,K+-ATPase, inhibited infection of cells with MHV, FIPV, Middle East respiratory syndrome (MERS)-CoV, and VSV, but not IAV, when the compounds were present during virus inoculation. Cardiotonic steroids were shown to inhibit entry of MHV at an early stage, resulting in accumulation of virions close to the cell surface and, as a consequence, in reduced fusion. In agreement with an early block in infection, the inhibition of VSV by CTSs could be bypassed by low-pH shock. Viral RNA replication was not affected when these compounds were added after virus entry. The antiviral effect of ouabain could be relieved by the addition of different Src kinase inhibitors, indicating that Src signaling mediated via ATP1A1 plays a crucial role in the inhibition of CoV and VSV infections

Publisher Correction: A human monoclonal antibody blocking SARS-CoV-2 infection (Nature Communications, (2020), 11, 1, (2251), 10.1038/s41467-020-16256-y)

The competing interests section of the original article contained an error. In the sentence “A patent application has been filed on 12 March 2020 on monoclonal antibodies targeting SARS-CoV-2 (United Kingdom patent application no. 2003632.3”, the number 2003632 was hyperlinked in error to an irrelevant page. The link has been removed both from the PDF and the HTML version of the article

Immunometabolism pathways as the basis for innovative anti-viral strategies (INITIATE): A Marie Sklodowska-Curie innovative training network

The past century has witnessed major advances in the control of many infectious diseases, yet outbreaks and epidemics caused by (re-) emerging RNA viruses continue to pose a global threat to human health. As illustrated by the global COVID19 pandemic, high healthcare costs, economic disruption and loss of productivity reinforce the unmet medical need to develop new antiviral strategies to combat not only the current pandemic but also future viral outbreaks. Pivotal for effective anti-viral defense is the innate immune system, a first line host response that senses and responds to virus infection. While molecular details of the innate immune response are well characterized, this research field is now being revolutionized with the recognition that cell metabolism has a major impact on the antiviral and inflammatory responses to virus infections. A detailed understanding of the role of metabolic regulation with respect to antiviral and inflammatory responses, together with knowledge of the strategies used by viruses to exploit immunometabolic pathways, will ultimately change our understanding and treatment of pathogenic viral diseases. INITIATE is a Marie Sklodowska-Curie Actions Innovative Training Network (MSCA-ITN), with the goal to train 15 early stage PhD researchers (ESRs) to become experts in antiviral immunometabolism (http

Identification of sialic acid-binding function for the Middle East respiratory syndrome coronavirus spike glycoprotein

Middle East respiratory syndrome coronavirus (MERS-CoV) targets the epithelial cells of the respiratory tract both in humans and in its natural host, the dromedary camel. Virion attachment to host cells is mediated by 20-nm-long homotrimers of spike envelope protein S. The N-terminal subunit of each S protomer, called S1, folds into four distinct domains designated S1A through S1D. Binding of MERS-CoV to the cell surface entry receptor dipeptidyl peptidase 4 (DPP4) occurs via S1B. We now demonstrate that in addition to DPP4, MERS-CoV binds to sialic acid (Sia). Initially demonstrated by hemagglutination assay with human erythrocytes and intact virus, MERS-CoV Sia-binding activity was assigned to S subdomain S1A. When multivalently displayed on nanoparticles, S1 or S1A bound to human erythrocytes and to human mucin in a strictly Sia-dependent fashion. Glycan array analysis revealed a preference for α2,3-linked Sias over α2,6-linked Sias, which correlates with the differential distribution of α2,3-linked Sias and the predominant sites of MERS-CoV replication in the upper and lower respiratory tracts of camels and humans, respectively. Binding is hampered by Sia modifications such as 5-N-glycolylation and (7,)9-O-acetylation. Depletion of cell surface Sia by neuraminidase treatment inhibited MERS-CoV entry of Calu-3 human airway cells, thus providing direct evidence that virus–Sia interactions may aid in virion attachment. The combined observations lead us to propose that high-specificity, low-affinity attachment of MERS-CoV to sialoglycans during the preattachment or early attachment phase may form another determinant governing the host range and tissue tropism of this zoonotic pathogen