Assuntos
Asma , Pólipos Nasais , Eosinofilia Pulmonar , Rinite , Sinusite , Anticorpos Monoclonais Humanizados , Asma/complicações , Asma/diagnóstico , Asma/tratamento farmacológico , Doença Crônica , Humanos , Interleucina-5 , Pólipos Nasais/complicações , Eosinofilia Pulmonar/induzido quimicamente , Eosinofilia Pulmonar/diagnóstico , Eosinofilia Pulmonar/tratamento farmacológico , Rinite/complicações , Rinite/diagnóstico , Rinite/tratamento farmacológico , Sinusite/complicações , Sinusite/tratamento farmacológicoRESUMO
Many viruses strongly prefer to infect certain cell types, a phenomenon known as "tropism." Understanding tropism's molecular basis is important for the design of vaccines and antiviral therapy. A common mechanism involves viral protein interactions with cell-specific surface receptors, but intracellular mechanisms involving translation have also been described. In this report, we focus on Hepatitis A Virus (HAV) tissue tropism from the standpoint of the translational machinery. HAV genomic RNA, like other positive stranded RNA viruses, is devoid of a cap structure and its translation is driven by highly structured RNA sequences termed internal ribosome entry site (IRES) in the 5' untranslated region (UTR). Unlike most viral IRESs, HAV IRES-mediated translation requires eIF4E and the 3' end of HAV RNA is polyadenylated. However, the molecular mechanism of HAV IRES-mediated translation initiation remains poorly understood. We analyzed HAV-IRES-mediated translation in a cell-free system derived from either non-hepatic cells (HeLa) or hepatoma cells (Huh-7) that enables investigation of the contribution of the cap and the poly(A) tail. This revealed that HAV IRES-mediated translation activity in hepatoma cell extracts is higher as compared to extracts derived from a non-hepatic line. Our data suggest that HAV IRES-mediated translation is upregulated by a hepatic cell-specific activator in a poly(A) tail-independent manner.
RESUMO
One kojibiose phoshorylase (KP) homolog gene was cloned from Caldicellulosiruptor saccharolyticus ATCC43494. Recombinant KP from C. saccharolyticus (Cs-KP) expressed in Escherichia coli showed highest activity at pH 6.0 at 85 °C, and was stable from pH 3.5 to 10.0 and up to 85 °C for phosphorolysis. Cs-KP showed higher productivity of kojioligosaccharides of DP ⧠4 than KP from Thermoanaerobacter brockii ATCC35047.
