Información Investigador: Yarzábal Rodríguez, Luis Andrés

Resumen Curricular: Obtuvo su Licenciatura en la Universidad Central de Venezuela en 1989. Culminó la Maestría en Biología Molecular (ULA) en 1995. En el año del 2003 obtuvo su Doctorado en Microbiología Molecular en la Universidad del Mediterráneo (Marsella, Francia). Es miembro fundador del Grupo de Microbiología Molecular y Biotecnología y actual Coordinador del Laboratorio del mismo nombre. Está adscrito al Postgrado Interdisciplinario de Biología Celular de la Facultad de Ciencias.Doctorado3527II - 2007; I - 200426 - 2005; 41 - 2003a) Aspectos genéticos, moleculares, fisiológicos y ecológicos de las interacciones entre bacterias y otros microorganismos del suelo (depredadores; competidores). b) Procesos de biofertilización y biomejoramiento de minerales, mediados por bacterias del suelo productoras de ácidos orgánicos (genética, fisiología y aplicaciones biotecnológicas).Agosto de 2006Licenciado en Biología+58 274 2401311Facultad de [email protected]

El plan de acción para la transformación de la educación superior en América Latina y el Caribe

EditorialBenítez, José Antonio; y Cadenas, EvelínRealidad y perspectiva de la universidad en el contexto latinoamericanoTünnermann B., CarlosEl plan de acción para la transformación de la educación superior en América Latina y el CaribeYarzabal, LuisMecanismos para el esbozo de un plan de anticipación-acción transformador de la educación superiorMedina, MisaelInforme final de las V Jornadas Nacionales de Planificación de la Educación Superior: De la anticipación a la acciónBenítez, José AntonioDeclaración mundial sobre educación superior en el siglo XXI: Visión y acciónOPI, LAC, UNESCOReglamento del Núcleo de Directores de PlanificaciónLlanos de la Hoz, Silvio; y Moyer, [email protected] analíticoanua

Cytochromes c of Acidithiobacillus ferrooxidans

The chemolithoautotrophic Gram-negative bacterium Acidithiobacillus ferrooxidans is versatile and can grow on a number of electron donors and acceptors. In the A. ferrooxidans ATCC 23270 genome, computer analysis identified 11 genes encoding putative cytochromes c. At least eight putative cytochromes c were differentiated on gels in ATCC 33020 cells grown on ferrous iron or sulfur. All these cytochromes were associated with the inner or the outer membranes. Lower levels of total cytochromes c were observed in sulfur- than in ferrous iron-grown cells. One cytochrome c was specific for sulfur conditions while three were specific for iron conditions, suggesting that cytochrome c synthesis is modulated depending on the electron [email protected]@ibsm.cnrs-mrs.f

Isolation and characterization of mineral phosphate-solubilizing bacteria naturally colonizing a limonitic crust in the south-eastern Venezuelan region

With the aim to explore the possible role of mineral phosphate-solubilizing bacteria (PSB) in phosphorus (P) cycling in iron-rich, acidic soils, we conducted a survey of PSB naturally colonizing a limonitic crust in the south-east region of Venezuela (Bolívar State). A total of 130 heterotrophic bacterial isolates showing different degrees of mineral tri-calcium phosphate (Ca3(PO4)2)-solubilizing activities were isolated from NBRIP plates. In contrast, no isolates showing iron phosphate (FePO4)- or aluminum phosphate (AlPO4)-solubilizing activities were detected by this experimental approach. The 10 best Ca3(PO4)2-solubilizers were selected for further characterization. These isolates were shown to belong to the genera Burkholderia, Serratia, Ralstonia and Pantoea by partial sequencing analysis of their respective 16S rRNA genes. All the PSB isolates were able to mediate almost complete solubilization of Ca3(PO4)2 in liquid cultures; in contrast, the PSB isolates were less effective when solubilizing FePO4. Two groups of PSB isolates were clearly differentiated on the basis of their Ca3(PO4)2 solubilization kinetics. Acidi.cation of culture supernatants seemed to be the main mechanism for P solubilization. Indeed, gluconic acid was shown to be present in the supernatant of .ve isolates. Furthermore, detection of genes involved in the production of this organic acid was possible in three isolates by means of a PCR protocol.2905–[email protected], [email protected]@[email protected]

Characterization of the mineral phosphate-solubilizing activity of pantoea aglomerans MMB051 isolated from an Iron-Rich soil in southeastern Venezuela (Bolívar State)

The mineral phosphate-solubilizing (MPS) activity of a Pantoea agglomerans strain, namely MMB051, isolated from an iron-rich, acidic soil near Ciudad Piar (Bolý´var State, Venezuela), was characterized on a chemically defined medium (NBRIP). Various insoluble inorganic phosphates, including tri-calcium phosphate [Ca3(PO4)2], iron phosphate (FePO4), aluminum phosphate (AlPO4), and Rock Phosphate (RP) were tested as sole sources of P for bacterial growth. Solubilization of Ca3(PO4)2 was very efficient and depended on acidification of the external milieu when MMB051 cells were grown in the presence of glucose. This was also the case when RP was used as the sole P source. On the other hand, the solubilization efficiency toward more insoluble mineral phosphates (FePO4 and AlPO4) was shown to be very low. Even though gluconic acid (GA) was detected on culture supernatants of strain MMB051, a consequence of the direct oxidation pathway of glucose, inorganic-P solubilization seemed also to be related to other processes dependent on active cell growth. Among these, proton release by ammonium (NH4) fixation appeared to be of paramount importance to explain inorganic-P solubilization mediated by strain MMB051. On the contrary, the presence of nitrate (NO3) salts as the sole N source affected negatively the ability of MMB051 cells to solubilize inorganic [email protected], [email protected]@[email protected]@ula.v

Introdução ao estudo da migração internacional na Amazônia Introduction to the study of international migration in the Amazon

Apesar da importância que a migração internacional alcançou na mídia e na academia no mundo inteiro, existem somente uns poucos estudos esparsos sobre a migração internacional na Amazônia. Como se apresenta o processo de migração internacional na Amazônia e qual é a sua importância nos destinos da região? Este artigo busca se aproximar da resposta a essa pergunta. O texto sintetiza resultados de investigações recentes realizadas pelo Grupo de Pesquisa Meio Ambiente, População e Desenvolvimento da Amazônia (MAPAZ), do Núcleo de Altos Estudos Amazônicos (NAEA) da Universidade Federal do Pará. Primeiramente, destaca-se a dificuldade de se definir a Amazônia; posteriormente, são apresentadas algumas considerações sobre a migração internacional em nível da Grande Região, agregando os migrantes acumulados nas respectivas Amazônias nacionais, conforme os censos de população de cada país; e, finalmente, trata-se essa problemática no caso da Amazônia brasileira, destacando os países de nascimento e a distribuição espacial dos migrantes na Amazônia Legal. Na Amazônia, os padrões e as tendências discutidas aqui se tornarão mais dinâmicos e complexos em função do andamento de políticas de desenvolvimento na busca da integração regional e econômica.<br>Despite the importance that international migration has attained in the media and academia worldwide, there are only a few scattered studies on international migration in the Amazon. How is the process of international migration presented in the Amazon and what is its importance in the destiny of the region? This article is an initial approach to that question. The text summarizes results of recent research conducted by the Research Group on Environment, Population and Development in the Amazon (MAPAZ) of the Center for Advanced Amazonian Studies (NAEA) of the Federal University of Pará. First, it discusses the difficulty of defining the Amazon, then some considerations are made about international migration in the Greater Amazon Region, aggregating the accumulated migrants of the national portions, according to the census of population of each country, and, finally, this issue is considered with regard to Brazilian Amazon highlighting countries of birth and the spatial distribution of migrants in the Amazon. In the Amazon the patterns and trends discussed here will become more dynamic and complex as development policies in pursuit of regional integration and economic development advance