A I131V Substitution in the Fusion Glycoprotein of Human Parainfluenza Virus Type 1 Enhances Syncytium Formation and Virus Growth.

Human parainfluenza virus type 1 (hPIV1) has two spike glycoproteins, the hemagglutinin-neuraminidase (HN) glycoprotein as a receptor-binding protein and the fusion (F) glycoprotein as a membrane-fusion protein. The F glycoprotein mediates both membrane fusion between the virus and cell and membrane fusion between cells, called syncytium formation. Wild-type C35 strain (WT) of hPIV1 shows little syncytium formation of infected cells during virus growth.

Easy and Rapid Detection of Mumps Virus by Live Fluorescent Visualization of Virus-Infected Cells.

Mumps viruses show diverse cytopathic effects (CPEs) of infected cells and viral plaque formation (no CPE or no plaque formation in some cases) depending on the viral strain, highlighting the difficulty in mumps laboratory studies. In our previous study, a new sialidase substrate, 2-(benzothiazol-2-yl)-4-bromophenyl 5-acetamido-3,5-dideoxy-α-D-glycero-D-galacto-2-nonulopyranosidonic acid (BTP3-Neu5Ac), was developed for visualization of sialidase activity. BTP3-Neu5Ac can easily and rapidly perform histochemical fluorescent visualization of influenza viruses and virus-infected cells without an antiviral antibody and cell fixation.

Rapid Fluorescent Detection Assay for Human Parainfluenza Viruses.

Human parainfluenza virus type 1 (hPIV1) does not form clear plaque by the conventional plaque formation assay because of slightly a cytopathic effects in many cell lines infected with hPIV1, thus making in virus titration, isolation and inhibitor evaluation difficult. We have succeeded in fluorescent histochemical visualization of sialidase activities of influenza A and B viruses, Newcastle disease virus and Sendai virus by using a novel fluorescent sialidase substrate, 2-(benzothiazol-2-yl)-4-bromophenyl 5-acetamido-3,5-dideoxy-α-D-glycero-D-galacto-2-nonulopyranosidonic acid (BTP3-Neu5Ac). In this study, we applied the BTP3-Neu5Ac assay for rapid detection of hPIV1 and hPIV type 3.

A novel method for detection of Newcastle disease virus with a fluorescent sialidase substrate.

Newcastle disease virus (NDV), belonging to the family Paramixoviridae, causes respiratory and neuronal symptoms in almost all birds. NDV has haemagglutinin-neuraminidase (HN) glycoprotein possessing sialidase activity. HN glycoprotein is highly expressed on the surface of NDV-infected cells, resulting in much higher sialidase activity in NDV-infected cells than in non-infected cells.

Histochemical fluorescent staining of Sendai virus-infected cells with a novel sialidase substrate.

Sialidases, enzymes that remove terminal sialic acid residues, are pivotal in various biological processes such as malignancy and infection with pathogens. For histochemical staining of sialidase activity, we have developed a new synthetic sialidase substrate, sialic acid-conjugated fluorescent benzothiazolylphenol derivative (BTP3-Neu5Ac), for rapid, sensitive, and specific fluorescent staining of sialidase activity. Here, we showed the usefulness of BTP3-Neu5Ac for histochemical fluorescent staining of cells infected with Sendai virus (SV), which possesses sialidase activity.

Imaging of influenza virus sialidase activity in living cells.

Influenza virus is rich in variation and mutations. It would be very convenient for virus detection and isolation to histochemically detect viral infection regardless of variation and mutations. Here, we established a histochemical imaging assay for influenza virus sialidase activity in living cells by using a new fluorescent sialidase substrate, 2-(benzothiazol-2-yl)-4-bromophenyl 5-acetamido-3,5-dideoxy-α-D-glycero-D-galacto-2-nonulopyranosidonic acid (BTP3-Neu5Ac).