PROIMI   05436
PLANTA PILOTO DE PROCESOS INDUSTRIALES MICROBIOLOGICOS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Arsenic bioenergetics in haloarchaea from Diamante Lake (Andean Puna)
Autor/es:
STEPANENKO TATIANA MARIEL; FARIAS MARIA EUGENIA; SAONA LUIS ALBERTO; SORIA MARIANA NOELIA
Lugar:
Ischia
Reunión:
Congreso; 12th International Congress of Extremophiles; 2018
Institución organizadora:
International Society for Extremophiles-Italian Society of Astrobiology
Resumen:
Diamante Lake is an unusual and rare environment owing to its extreme conditions, resembling some of the ancient Earths lacustrine habitats. Its most important characteristic is the high content of arsenic (As) never before described in natural environments: 234 mg/L (1,2). Under such conditions, red haloarchaea (Euryarchaeota phylum) biofilms develop at the bottom of calcium carbonate microbialites. In addition, metagenomic analyzes of this ecosystem revealed a high abundance of genes used for arsenite oxidation (aioBA) and respiratory arsenate reduction (arrCBA), which suggests that these haloarchaea could use arsenic compounds to grow (1). To verify the importance of arsenic as a bioenergetic component, in this work we carried out physiological and molecular assays in the haloarquea Halorubrum sp. DM2, isolated from the biofilm of Diamante lake (3). The anaerobic and aerobic growth of this strain was determined in minimal medium (CDM-pyruvate), with different electron donors (As III, SO32-, NO2-) and acceptors (As V, SO42-, NO3-) and in light /dark conditions. We observed that in the presence of arsenate (As V) the anaerobic growth of Halorubrum sp. DM2 was greater with respect to the control and the other conditions tested, and independently of the presence/absence of light. However, no growth differences were observed in aerobiosis. Moreover, qPCR assays were carried out to analyze the expression of arsenic metabolism genes in the previously tested conditions, observing an increase in the transcriptional levels of aio when arsenic was added to the growth medium. These results suggest that Halorubrum sp. DM2 is able to use arsenic as a bioenergetics substrate to sustain its growth. Although it is not yet possible to assign the molecular mechanism by which this process would be carried out, the increase of the expression of the arsenite oxidase (aio) gene, would give us a guide on which way we should continue exploring to unravel this adaptation never reported before in haloarchaea of Euryarchaeota phylum.