Demergasso C.,Catolica del Norte University |
Demergasso C.,Centro de Investigacion Cientifico tecnologico para la Mineria |
Dorador C.,Catolica del Norte University |
Meneses D.,Catolica del Norte University |
And 6 more authors.
Journal of Geophysical Research: Biogeosciences | Year: 2010
The Chilean Altiplano is the westernmost part of a large volcanic-sedimentary plateau in the central Andes. High solar irradiance and rapid increase of temperature have contributed to make it a hot spot of global climatic change. In this study, we describe microbial diversity in the summit lake of the Simba volcano (5,870 m) and the evaporitic basins of Salar de Aguas Calientes (4,200 m) and Laguna Lejía (4,325 m) using both culture and culture-independent methods. The results obtained were analyzed together with available information from related environments to describe the traits of the microbial community driven by main environmental factors. Isolated cultures exhibit high resistance to all three types of UV radiation, further supporting the adaptation of microorganisms to the high altitude environment. The microbial community structures at Salar de Aguas Calientes and Laguna Lejía are similar to those from other saline systems and cold environments where Bacteroidetes is the major bacterial group. The abundance of sequences related to alphaproteobacteria and methanogenic populations likely reflects the importance of aerobic anoxigenic phothosynthesis and the cycling of one-carbon compounds in the high altitude lake ecosystems. Geochemistry and microbial communities at Simba as well as those reported in the Licancabur summit lake provide evidence for sulfur-rich environments but under different conditions. Those differences between neighboring mountain lake ecosystems highlight the effect of volcanic activity on microbial communities. The hypothetical ecosystem model described in this work provides a clue to follow the microbial community responses to geophysical environment coupled with rapid climate change. Copyright 2010 by the American Geophysical Union.
Pugin B.,University of Georgia |
Blamey J.M.,Fundacion Biociencia |
Baxter B.K.,Westminster College, Utah |
Wiegel J.,University of Georgia
International Journal of Systematic and Evolutionary Microbiology | Year: 2012
Novel strains of facultatively aerobic, moderately alkaliphilic and facultatively halophilic bacteria were isolated from a sediment sample taken from the Southern Arm of Great Salt Lake, Utah. Cells of strain JW/BP-GSL-QDT (and related strains JW/BP-GSL-RA and JW/BP-GSL-WB) were rod-shaped, spore-forming, motile bacteria with variable Gram-staining. Strain JW/BP-GSLQDT grew under aerobic conditions between 14.5 and 47 oC (optimum 39 oC), in the pH37°C range 6.5-10.3 (optimum pH37°C 8.0), and between 0.1 and 4.5 M Na+ (optimum 0.9 M Na+). No growth was observed in the absence of supplemented Na+. Strain JW/BP-GSL-QDT utilized L-arabinose, D-fructose, D-galactose, D-glucose, inulin, lactose, maltose, mannitol, D-mannose, pyruvate, D-ribose, D-sorbitol, starch, trehalose, xylitol and D-xylose under both aerobic and anaerobic conditions, and used ethanol and methanol only under aerobic conditions. Strains JW/ BP-GSL-WB and JW/BP-GSL-RA had the same profiles except that methanol was not used aerobically. During growth on glucose, the major organic compounds formed under aerobic conditions were acetate and lactate, and under anaerobic conditions, the fermentation products were formate, acetate, lactate and ethanol. Oxidase and catalase activities were not detected and cytochrome was absent. No respiratory quinones were detected. The main cellular fatty acids were iso-C15: 0 (39.1 %) and anteiso-C15: 0 (36.3 %). Predominant polar lipids were diphosphatidylglycerol, phosphatidylglycerol and an unknown phospholipid. Additionally, a small amount of an unknown glycolipid was detected. The DNA G+C content of strain JW/BP-GSLQDT was 35.4 mol% (determined by HPLC). For strain JW/BP-GSL-QDT the highest degree of 16S rRNA gene sequence similarity was found with Amphibacillus jilinensis (98.6 %), Amphibacillus sediminis (96.7 %) and Amphibacillus tropicus (95.6 %). The level of DNA-DNA relatedness between strain JW/BP-GSL-QDT and A. jilinensis Y1T was 58 %. On the basis of physiological, chemotaxonomic and phylogenetic data, strain JW/BP-GSL-QDT represents a novel species of the genus Amphibacillus, for which the name Amphibacillus cookii sp. nov. is proposed. The type strain is JW/BP-GSL-QDT (=ATCC BAA-2118T=DSM 23721T). © 2012 IUMS Printed in Great Britain.
Sancy M.,Academia Polytechnic Aeronautica |
Abarzua A.,Academia Polytechnic Aeronautica |
Azocar M.I.,University of Santiago de Chile |
Blamey J.M.,Fundacion Biociencia |
And 4 more authors.
Journal of Electroanalytical Chemistry | Year: 2015
In this paper we studied the influence of bacterial consortia on corrosion of fuel tanks of aircraft used often for pilot training. In the first part, we proceeded to the isolation and characterization of the consortia by DNA sequencing. The consortium was mainly constituted by two bacteria, which have a close affiliation to Bacillus subtilis and to Bacillus circulans. The substrate used in fuel tanks was an aluminum alloy 2024. Electrochemical measurements and morphological characterization were performed for different immersion times (1, 2, 3, 7 and 14 days) in sterile minimal salt medium (MSM) and in inoculated media (MSM + B. subtilis and MSM + consortia). For all immersion times, impedance diagrams showed a capacitive behavior characterized by a single constant time. Although for short exposure times, no corrosion process was evidenced, for longer exposure time, the resistance of the aluminum oxide (Rox) decreased markedly, indicating that a corrosion process was taking place. ©2014 Elsevier B.V. All rights reserved.
Correa-Llanten D.,Fundacion Biociencia |
Correa-Llanten D.,University of Santiago de Chile |
Larrain-Linton J.,Fundacion Biociencia |
Munoz P.A.,Fundacion Biociencia |
And 5 more authors.
Korean Journal of Microbiology and Biotechnology | Year: 2013
A gram-positive, rod-shaped, spore-forming, motile thermophilic bacterium was isolated from a sterilization oven. The microorganism GWE1, formally named Geobacillus wiegelii identified as a member of the genus Geobacillus. GWE1 grew under aerobic conditions of between 60-80°C (optimum 70°C), in a pH range of 3.0-8.0 (optimum pH70°C 5.8), and between 0 and 2 M NaCl (optimum 0.3 M). The membrane polar lipids were dominated by branched saturated fatty acids, which included as the major constituents; iso-15:0 (13.3%), 16:1(ω7) (12.8%), 16:0 (28.5%), iso-17:0 (13.5%) and anteiso-17:0 (12.3%). The DNA G+C content was 47.2 mol% (determined by HPLC). The 16S rRNA gene sequence of GWE1 showed a high similarity with Geobacillus caldoxylosilyticus (97%). However, the level of DNA-DNA relatedness was only 58%. These data suggest that GWE1 is probably a novel specie of the genus Geobacillus. © 2013, The Korean Society for Microbiology and Biotechnology.