Comparison of virus concentration methods and RNA extraction methods for SARS-CoV-2 wastewater surveillance.

Wastewater surveillance is a promising tool for population-level monitoring of the spread of infectious diseases, such as the coronavirus disease 2019 (COVID-19). Different from clinical specimens, viruses in community-scale wastewater samples need to be concentrated before detection because viral RNA is highly diluted. The present study evaluated eleven different virus concentration methods for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in wastewater.

Neuraminidase activity and specificity of influenza A virus are influenced by haemagglutinin-receptor binding.

Influenza virus haemagglutinin (HA) and neuraminidase (NA) are involved in the recognition and modulation of sialic acids on the cell surface as the virus receptor. Although the balance between two proteins functions has been found to be crucial for viral fitness, the interplay between the proteins has not been well established. Herein we present evidence for interplay between influenza HA and NA, which may affect the balance between two glycoprotein functions.

Unravelling the Role of O-glycans in Influenza A Virus Infection.

The initial stage of host cell infection by influenza A viruses (IAV) is mediated through interaction of the viral haemagglutinin (HA) with cell surface glycans. The binding requirement of IAVs for Galβ(1,4)Glc/ GlcNAc (lactose/lactosamine) glycans with a terminal α(2,6)-linked (human receptors) or α(2,3)-linked (avian receptors) N-acetylneuraminic residue commonly found on N-glycans, is well-established. However the role and significance of sialylated Galβ(1,3)GalNAc (core 1) epitopes that are typical O-glycoforms in influenza virus pathogenesis remains poorly detailed.

Tropism and innate host responses of influenza A/H5N6 virus: an analysis of and cultures of the human respiratory tract.

Since their first isolation in 2013, influenza A/H5N6 viruses have spread amongst poultry across multiple provinces in China and to Laos, Vietnam and Myanmar. So far, there have been 14 human H5N6 infections with 10 fatalities.We investigated the tropism, replication competence and cytokine induction of one human and two avian H5N6 isolates in and cultures derived from the human respiratory tract.

Toll-like receptor 10 is involved in induction of innate immune responses to influenza virus infection.

Toll-like receptors (TLRs) play key roles in innate immune recognition of pathogen-associated molecular patterns of invading microbes. Among the 10 TLR family members identified in humans, TLR10 remains an orphan receptor without known agonist or function. TLR10 is a pseudogene in mice and mouse models are noninformative in this regard.

Investigation of the binding and cleavage characteristics of N1 neuraminidases from avian, seasonal, and pandemic influenza viruses using saturation transfer difference nuclear magnetic resonance.

Objectives: The main function of influenza neuraminidase (NA) involves enzymatic cleavage of sialic acid from the surface of host cells resulting in the release of the newly produced virions from infected cells, as well as aiding the movement of virions through sialylated mucus present in the respiratory tract. However, there has previously been little information on the binding affinity of different forms of sialylated glycan with NA. Our objectives were then to investigate both sialic acid binding and cleavage of neuraminidase at an atomic resolution level.

Production of influenza pseudotyped lentiviral particles and their use in influenza research and diagnosis: an update.

Pseudotyped viral particles are being used as safe surrogates to mimic the structure and surface of many viruses, including highly pathogenic viruses such as avian influenza H5N1, to investigate biological functions mediated by the envelope proteins derived from these viruses. The first part of this article evaluates and discusses the differences in the production and characterization of influenza pseudoparticles. The second part focuses on the applications that such a flexible tool can provide in modern influenza research, in particular in the fields of drug discovery, molecular biology and diagnosis.

Formation of virus-like particles from human cell lines exclusively expressing influenza neuraminidase.

The minimal virus requirements for the generation of influenza virus-like particle (VLP) assembly and budding were reassessed. Using neuraminidase (NA) from the H5N1 and H1N1 subtypes, it was found that the expression of NA alone was sufficient to generate and release VLPs. Biochemical and functional characterization of the NA-containing VLPs demonstrated that they were morphologically similar to influenza virions.

Effects of moderate and substantial hypoxia on erythropoietin levels in rainbow trout kidney and spleen.

Erythropoietin (EPO) is a glycoprotein hormone that regulates the proliferation and differentiation of erythroid progenitor cells in mammals. Although EPO has been identified in fish, the specific function and effects of hypoxia have not been investigated previously. In this study, we have demonstrated a relationship between increases in renal EPO levels and decreases in spleen EPO levels and spleen-somatic index (SSI), with increases in haemoglobin (Hb) concentration in the blood during hypoxia exposure in rainbow trout.