UV-RESISTANT BACTERIA FROM HIGH-ALTITUDE ANDEAN LAKES: GENOMIC AND ULTRASTRUCTURAL STUDIES

MARTINEZ, L.; ALBARRACÍN V. H.; GALVÁN, F. S.; SIÑERIZ, M.; ALONSO REYES D.; FARIAS M.E.

Valparaiso

Congreso; 1st ISME Latin America Congress; 2019

Universidad Técnica Federico Santa María

The HAALs are situated in northwest Argentina, Chile, and Bolivia at higher altitudes than 3,000 m. Their microbial communities have developed mechanisms for adaptations to extreme environmental factors, specifically UV. They constituted interesting models to carry out studies of compounds and systems involved in such adaptation, with promising biotechnological applications. In this work, we analyzed the genome and ultrastructure of two poly-extremophilic bacteria upon UV-exposure: Exiguobacterium sp. S17 isolated from modern stromatolites from Laguna Socompa (3,750 masl) and Acinetobacter sp. Ver3 isolated from the Laguna Verde (4,100 masl). Cell cultures of S17 and Ver3 were subjected to artificial UV-B radiation for different times: 0 (control), 60, 90 and 120 min, taking aliquots at each time for SEM and TEM. Genome annotation of both strains were performed using the standard operating procedures (SOPs) for prokaryotic annotation from ISGA and from the RAST annotation server. BLAST was used to compare the genome with nearby species. The results showed that UV-B exposure tends to favor a greater degree of bacterial aggregation and intercellular communications, probably as a protection mechanism against radiation stress. Genomic survey indicated in both strains the presence of coding genes for intercellular pili type IV. In Ver3 are present the genes pilE, pilV, pilX, pilQ and the pilC, pilT, PilB, where the latter were also found in S17, and are responsible the assembly and the formation of aggregates and adhesion to surfaces. In future research, the aims are to examine the proteome and transcriptome of systems that involve intercellular communication.