Synthesis, characterization and kinetic study of silver and gold nanoparticles produced by the archaeon Haloferax volcanii.

AIMS: To evaluate the ability of the haloarchaeon Haloferax volcanii to produce Ag and Au nanoparticles (NPs) and to characterize the obtained material in order to find relevant properties for future potential applications. METHODS AND RESULTS: Nanoparticles were produced by incubating H. volcanii cells with the corresponding metal salt. In the presence of precursor salts, cultures evidenced a colour change associated to the formation of metallic nanostructures with plasmonic bands located in the visible range of the spectrum. X-ray fluorescence analysis confirmed the presence of Ag and Au in the NPs which were spherical, with average sizes of 25 nmol l-1 (Ag) and 10 nmol l-1 (Au), as determined by electronic microscopy. Fourier transformed infrared spectroscopy indicated that both types of NPs showed a stable protein capping. Ag NPs evidenced antibacterial activity and Au NPs improved the specificity of polymerase chain reaction reactions. Au and Ag NPs were able to reduce 4-nitrophenol when incubated with NaBH4 . CONCLUSIONS: Haloferax volcanii is able to synthesize metallic NPs with interesting properties for technological applications. SIGNIFICANCE AND IMPACT OF THE STUDY: Our data demonstrate the ability of H. volcanii to synthesize metal NPs and constitutes a solid starting point to deepen the study and explore novel applications.

Comunicación oral: aspectos básicos de su desarrollo, patología y tratamiento / Oral comunication: main aspects of its pathology and treatment

Se presenta una perspectiva interdisciplinaria actual incluyendo una introducción a los fundamentos para el diagnóstico y tratamiento de los problemas de la comunicación oral. Está destinada a médicos generales, otorrinolaringólogos pediatras y profesores, en formación. Se hace especial hincapié en aquellos trastornos derivados de problemas auditivos y se presentan los medios actuales avanzados. Asimismo se explica la importancia de promover la creación de nuevas unidades multidisciplinarias para diagnosticar y tratar estos problemas.

A current interdisciplinary perspective including an introduction to the fundamentals of the approach to diagnostic and treatment of speech communication disorders is presented. The diagnostic and therapeutic procedures are presented with special emphasis on those advanced and related to hearing problems. Additionally the importance of promoting new multidisciplinary units is pointed out. The work is destined to general practitioners pediatricians, ENTs, and primary school teachers, under education process.

Development of a nasal vaccine for chronic hepatitis B infection that uses the ability of hepatitis B core antigen to stimulate a strong Th1 response against hepatitis B surface antigen.

There are estimated to be 350 million chronic carriers of hepatitis B infection worldwide. Patients with chronic hepatitis B are at risk of liver cirrhosis with associated mortality because of hepatocellular carcinoma and other complications. An important goal, therefore, is the development of an effective therapeutic vaccine against chronic hepatitis B virus (HBV). A major barrier to the development of such a vaccine is the impaired immune response to HBV antigens observed in the T cells of affected patients. One strategy to overcome these barriers is to activate mucosal T cells through the use of nasal vaccination because this may overcome the systemic immune downregulation that results from HBV infection. In addition, it may be beneficial to present additional HBV epitopes beyond those contained in the traditional hepatitis B surface antigen (HbsAg) vaccine, for example, by using the hepatitis B core antigen (HBcAg). This is advantageous because HBcAg has a unique ability to act as a potent Th1 adjuvant to HbsAg, while also serving as an immunogenic target. In this study we describe the effect of coadministration of HBsAg and HBcAg as part of a strategy to develop a more potent and effective HBV therapeutic vaccine.