RESUMEN
Thermococcus kodakarensis possesses two DNA polymerases, Pol B and Pol D. We generated a T. kodakarensis strain (DPB1) in which polB was completely deleted and a derivative of DPB1 in which polB was overexpressed; neither of the generated strains exhibited any growth delay, indicating that the lack or overexpression of Pol B in T. kodakarensis did not affect cell growth. We also found that DPB1 showed higher sensitivity to four DNA-damaging agents (ultraviolet C irradiation, γ-ray irradiation, methyl methanesulfonate, and mitomycin C) than the parental strain. The sensitivity of DPB1 was restored to the level of the parent strain by the introduction of a plasmid harboring polB, suggesting that the DNA damage-sensitive phenotype of DPB1 was due to the loss of polB. Collectively, these results indicate that Pol B is involved in DNA repair, but not DNA replication, which, in turn, implies that Pol D is the sole replicative DNA polymerase in Thermococcus species.
Asunto(s)
Reparación del ADN/genética , ADN de Archaea/genética , ADN Polimerasa Dirigida por ADN/genética , Thermococcus/enzimología , Thermococcus/genética , Proteínas Bacterianas/genética , Daño del ADN/efectos de los fármacos , Daño del ADN/genética , Reparación del ADN/efectos de los fármacos , Replicación del ADN , Eliminación de Gen , Expresión Génica , Inhibidores de la Síntesis del Ácido Nucleico/farmacología , Thermococcus/efectos de los fármacosRESUMEN
A nanoimprint-lithography-based fabrication method to generate stable protein films is described. The process is environmentally friendly and generalizable with respect to the protein building blocks. These non-fouling surfaces are readily patternable, incorporate intrinsic protein charge into the film, and able to control cellular adhesion.
Asunto(s)
Nanoestructuras , Proteínas , Células 3T3 , Animales , Bovinos , Adhesión Celular , Dicroismo Circular , Fibroblastos/citología , Fibroblastos/fisiología , Hemoglobinas/química , Ratones , Microscopía de Fuerza Atómica , Microscopía Fluorescente , Muramidasa/química , Presión , Proteínas/síntesis química , Proteínas/química , Albúmina Sérica Bovina/química , Propiedades de Superficie , Temperatura , Agua/químicaRESUMEN
A facile method is developed to functionalize nanofiber surfaces with nanoparticles (NPs) through dithiocarbamate chemistry. Gold nanoparticles (AuNPs) and quantum dots (QDs) are immobilized on the nanofiber surface. These surfaces provide scaffolds for further supramolecular functionalization, as demonstrated through the Förster resonance energy transfer (FRET) pairing of QD-decorated fibers and fluorescent proteins.
Asunto(s)
Técnicas Biosensibles/instrumentación , Nanopartículas del Metal/química , Nanofibras/química , Oro/química , Puntos Cuánticos/químicaRESUMEN
The intrinsic coagulation activity of silica nanoparticles strongly depends on their surface curvature. Nanoparticles with higher surface curvature do not denature blood coagulation factor XII on its surface, providing a coagulation 'silent' surface, while nanoparticles with lower surface curvature show denaturation and concomitant coagulation.