Asunto(s)
Asma , Pólipos Nasales , Eosinofilia Pulmonar , Rinitis , Sinusitis , Anticuerpos Monoclonales Humanizados , Asma/complicaciones , Asma/diagnóstico , Asma/tratamiento farmacológico , Enfermedad Crónica , Humanos , Interleucina-5 , Pólipos Nasales/complicaciones , Eosinofilia Pulmonar/inducido químicamente , Eosinofilia Pulmonar/diagnóstico , Eosinofilia Pulmonar/tratamiento farmacológico , Rinitis/complicaciones , Rinitis/diagnóstico , Rinitis/tratamiento farmacológico , Sinusitis/complicaciones , Sinusitis/tratamiento farmacológicoRESUMEN
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.
Asunto(s)
Proteínas Bacterianas/metabolismo , Disacáridos/metabolismo , Fosforilasas/metabolismo , Proteínas Recombinantes/metabolismo , Thermoanaerobacterium/enzimología , Proteínas Bacterianas/genética , Clonación Molecular , Escherichia coli , Calor , Concentración de Iones de Hidrógeno , Cinética , Fosforilasas/genética , Plásmidos , Proteínas Recombinantes/genética , Especificidad por Sustrato , Thermoanaerobacterium/química , Transformación BacterianaRESUMEN
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.