PROIMI   05436
PLANTA PILOTO DE PROCESOS INDUSTRIALES MICROBIOLOGICOS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Genome sequence analysis of Acinetobacter sp. Ver3 and Exiguobacterium sp. S17 isolated from High Altitude Andean Lakes?.
Autor/es:
KURTH, D; ORDOÑEZ, OF; ALBARRACIN, V; CORTEZ, N; TURJANSKI, A; VAZQUEZ, M; FARIAS, ME
Lugar:
Santiago, Chile
Reunión:
Conferencia; The second International Society for Computational Biology Latin American regional meeting (ISCB-Latin America); 2012
Institución organizadora:
International Society for Computational Biology Latin American
Resumen:
The High-Altitude Andean Lakes (HAAL) ecosystems are almost unexplored systemsof shallow lakes formed during the Tertiary geological period, distributed in thegeographical area called the Puna, at altitudes from 3,000 to 6,000 m above sea level,and isolated from direct human activity. The HAAL ecosystems are unique not only fortheir geographical characteristics and broad range of extreme environments but alsofor their abundant biodiversity. The microbial communities that have evolved withinthese high-altitude aquatic ecosystems tolerate chemical and physical stresses suchas wide fluctuations in daily temperatures, hypersalinity, and variable pH and haveproved to be adapted to high levels of UV radiation, a low level of nutrient availability,and high concentrations of heavy metals.Here we present and analyze genomic sequences of two bacteria isolated from theseextreme environments. They include Acinetobacter sp. Ver3, isolated from LagunaVerde, and Exiguobacterium sp. S17, isolated from Laguna Socompa. Genomesequences were obtained using a whole-genome shotgun (WGS) strategy with a 454GS Titanium pyrosequencer at INDEAR, Argentina. From the annotated genomes,loaded on RAST annotation server, functional analysis shows remarkable features.Particularly Acinetobacter sp. Ver3 shows a high number of genes in the category ofVirulence, Disease and Defense, which includes genes conferring resistance toantibiotics and heavy metals.We are most interested in genomic features related to survival of these organisms inthe harsh conditions prevailing at the HAAL. We focused our analysis on arsenicresistance. The high number of antibiotic resistance genes found in theseenvironments is surprising, as no selective pressure due to human contact can beexpected. The presence of such genes suggests that new compounds could beisolated from these environments. DNA repair systems were also studied, as all theseisolates are highly resistant to UV-B radiation. However, no unique genes were found.The improved resistance could be explained due to more efficient interactions orregulation of common repair systems. Further analysis will be required to associate thisphenotype to the presence/absence of particular genes.Finally we performed a detailed analysis of the genes associated to arsenic resistance.The most well characterized arsenic resistance mechanism is the ars operon locatedon plasmids/chromosomes of prokaryotes. HAAL isolates show enhanced resistancecompared to other bacteria possessing the ars operon. This is explained by thepresence of additional genes related to this function, including extra copies of the arsoperon (in Acinetobacter sp. Ver3) or supplementary extrusion pumps (inExiguobacterium sp. S17). The origin of these genes, either by horizontal gene transferor duplication events, is discussed.