RESUMO
Electrostatics is one of the fundamental driving forces of the interaction between biomolecules in solution. In particular, the recognition events between viruses and host cells are dominated by both specific and non-specific interactions and the electric charge of viral particles determines the electrostatic force component of the latter. Here we probe the charge of individual viruses in liquid milieu by measuring the electrostatic force between a viral particle and the Atomic Force Microscope tip. The force spectroscopy data of co-adsorbed Ï29 bacteriophage proheads and mature virions, adenovirus and minute virus of mice capsids is utilized for obtaining the corresponding density of charge for each virus. The systematic differences of the density of charge between the viral particles are consistent with the theoretical predictions obtained from X-ray structural data. Our results show that the density of charge is a distinguishing characteristic of each virus, depending crucially on the nature of the viral capsid and the presence/absence of the genetic material.
Assuntos
Adenoviridae , Fagos Bacilares , Vírus Miúdo do Camundongo , Vírion , Adenoviridae/química , Adenoviridae/ultraestrutura , Animais , Fagos Bacilares/química , Fagos Bacilares/ultraestrutura , Camundongos , Microscopia de Força Atômica , Vírus Miúdo do Camundongo/química , Vírus Miúdo do Camundongo/ultraestrutura , Eletricidade Estática , Vírion/química , Vírion/ultraestruturaRESUMO
Pseudodiverticulum of the hypopharynx is an infrequent but potentially serious complication of orogastric or nasogastric tube insertion and endotracheal intubation. We report two cases of injury to the hypopharynx resulting in a pseudodiverticulum of the hypopharynx that was initially diagnosed as esophageal atresia. Both cases were managed successfully by conservative therapy. We also review the literature regarding neonatal pharyngeal pseudodiverticulum.