ABSTRACT
Adequate treatment of influenza requires identification of viral type as well as detection of mutation(s) conferring drug resistance. Reverse hybridization-based line probe assays (LiPA) can be performed using several probes immobilized on nitrocellulose, strips enabling LiPA to determine simultaneously viral subtypes and detect the presence or absence of the H274Y mutation, which confers oseltamivir resistance of H1N1 influenza viruses. LiPA was developed for identification of H1N1 influenza virus subtypes (pandemic 2009 and seasonal types), as well as H3N2 and B subtypes, and to detect the H274Y mutation. The diagnostic capability of this assay was evaluated using cultured virus isolates as well as nasal swabs obtained from patients suspected of infection with influenza. In examining 354 cultured virus isolates, the LiPA showed 100% specificity for virus typing and 99% specificity for detecting the H274Y mutation. In 49 nasal swabs from a clinical study, the assay showed 100% specificity for virus typing and 88% specificity for detecting the absence of the H274Y mutation, although none of these swabs was PCR-positive for this mutation. These findings indicate that LiPA for influenza viruses may be used to monitor viral trends during the influenza season.
Subject(s)
Influenza A Virus, H1N1 Subtype/classification , Mutation , Reagent Kits, Diagnostic , Reverse Transcriptase Polymerase Chain Reaction/methods , DNA Probes/chemistry , Genes, Viral , Humans , Influenza A Virus, H1N1 Subtype/genetics , Influenza A Virus, H1N1 Subtype/isolation & purification , Influenza A Virus, H3N2 Subtype/classification , Influenza A Virus, H3N2 Subtype/genetics , Influenza A Virus, H3N2 Subtype/isolation & purification , Influenza B virus/classification , Influenza B virus/genetics , Influenza B virus/isolation & purification , Influenza, Human/virology , Sensitivity and Specificity , Viral Proteins/analysis , Viral Proteins/geneticsABSTRACT
A maltose binding protein, p78, was purified to homogeneity from Aspergillus nidulans by a single column chromatography step on cross-linked amylose. The partial amino acid sequence was highly homologous to the glycogen branching enzymes (GBEs) of human and yeast, and p78 did show branching enzyme activity. The genomic gene and its cDNA encoding GBE (p78) were isolated from the A. nidulans genomic and cDNA libraries. Furthermore, a cDNA encoding A. oryzae GBE was entirely sequenced. A. nidulans GBE shared overall and significant amino acid sequence identity with GBEs from A. oryzae (83.9%), Saccharomyces cerevisiae (61.1%) and human (63.0%), and with starch branching enzymes from green plants (55-56%).