The temperature-sensitive hemagglutinin (Tsh) expressed by strains of avian pathogenic Escherichia (E.) coli (APEC) has both agglutinin and protease activities. Tsh is synthesized as a 140 kDa precursor protein, whose processing results in a 106 kDa passenger domain (Tsh(s)) and a 33 kDa β-domain (Tsh(β)). In this study, both recombinant Tsh (rTsh) and supernatants from APEC, which contain Tsh(...

Background: Although Escherichia coli (E. coli)is a part of intestinal normal microflora of warm-blooded animals, includingpoultry, outbreaks occur in poultry raised below standard sanitation and duringthe course of respiratory or immunosuppressive diseases. Avian pathogenic E.coli (APEC) harbors several genes associated with virulence andpathogenicity. APEC strains are responsible for some dis...

Avian pathogenic Escherichia coli (APEC) is an economically important respiratory pathogen of chickens worldwide. Factors previously associated with the virulence of APEC include adhesins, iron-scavenging mechanisms, the production of colicin V (ColV), serum resistance, and temperature-sensitive hemagglutination, but virulence has generally been assessed by parenteral inoculation, which does no...

The temperature-sensitive hemagglutinin (Tsh) is an autotransporter protein secreted by avian-pathogenic Escherichia coli strains that colonize the respiratory tract and lead to airsacculitis, pericarditis, and colisepticemia. It is synthesized as a 140-kDa precursor protein, whose processing results in a 106-kDa passenger domain (Tshs) and a 33-kDa beta-domain (Tsh(beta)). The presence of a co...

In this article, we report the isolation and characterization of a gene that may be important in the adherence of avian pathogenic Escherichia coli to the avian respiratory tract. The E. coli strain HB101, which is unable to agglutinate chicken erythrocytes, was transduced with cosmid libraries from the avian pathogenic E. coli strain chi 7122. Enrichment of transductants that could agglutinate...

Virions from Newcastle disease virus mutants in four temperature-sensitive RNA+ groups were grown in embryonated hen eggs at the permissive temperature, purified, and then analyzed for biological properties at both the permissive and nonpermissive temperatures. At the permissive temperature, virions of mutants in groups B, C, and BC (11 mutants) were all lower in specific (per milligram of prot...

background : avian influenza virus (aiv) infection is a major cause of bird and human morbidity and mortality. we aimed to evaluate a specific and sensitive multiplex rt-pcr that can simultaneously detect influenza type a viruses and differenti­ate the two most important subtypes of avian influenza viruses h7 and h9 subtypes. methods : a multiplex reverse transcriptase-polymerase chain reaction...