texas-red and Influenza--Human

Aggregation effects of gold nanoparticles (AuNPs) were examined for the discrimination of single point mutations through the hybridization of oligonucleotides (25-50 nM) modified with a fluorescent Texas red dye. The sequences of oligonucleotides were designed to detect the H1N1 virus gene. Single-base mismatch detection due to different adsorption propensities of oligonucleotides could be achieved using fluorescence quenching and surface-enhanced Raman scattering (SERS) properties of the dye. We observed that the addition of perfectly matched double stranded DNA (pmdsDNA), modified with the Texas red dye in the suspension of citrate-reduced AuNPs could increase fluorescence recovery intensities more substantially than either single-base mismatched double stranded DNA (sbmdsDNA) or single stranded DNA (ssDNA). We also tested DNA hybridization under both aggregation and near non-aggregation conditions for fluorescence measurements. A spectral difference in fluorescence intensity between pmdsDNA and sbmdsDNA appeared to be more discriminating under near non-aggregation than aggregation conditions. On the other hand, the SERS intensities of pmdsDNA and sbmdsDNA decreased more significantly than that of ssDNA under aggregation conditions, whereas we could not observe any SERS intensities under non-aggregation conditions.

Topics: Base Pair Mismatch; Base Sequence; Biosensing Techniques; DNA; DNA Probes; DNA, Single-Stranded; DNA, Viral; Fluorescent Dyes; Gold; Humans; Influenza A Virus, H1N1 Subtype; Influenza, Human; Metal Nanoparticles; Nucleic Acid Hybridization; Oligonucleotides; Spectrometry, Fluorescence; Spectrum Analysis, Raman; Xanthenes

Differences between isotypes of monoclonal antibodies were employed to detect influenza A and B viruses and respiratory syncytial virus by direct immunofluorescence using fluorescein isothiocyanate or Texas Red conjugates. Examination of 56 specimens for influenza A and B viruses and 112 specimens for influenza A virus and respiratory syncytial virus showed the mixed-isotype test to be comparable to the conventional procedure.

Topics: Antibodies, Monoclonal; Antibodies, Viral; Diagnosis, Differential; Evaluation Studies as Topic; Fluorescein-5-isothiocyanate; Fluorescent Antibody Technique, Direct; Fluorescent Dyes; Humans; Immunoglobulin Isotypes; Influenza A virus; Influenza B virus; Influenza, Human; Respiratory Syncytial Virus Infections; Respiratory Syncytial Viruses; Xanthenes