Stefan Leuko
Received Mag. Rer. Nat (equivalent to M.Sc.) in 2004 in Salzburg (Paris-Lodron University)
PhD Student
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Contact Details: Phone: + 61 2 9385 2098 Email: sleuko@bio.mq.edu.au
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Research area: Microbial adaptation physiologies to fluxes in desiccation and salinity of
coastal ecosystems.
My first contact with microbiology and molecular genetics was during the final year of high school. We learned about the DNA replication mechanism and about those tiny forms of life you normally don't see. Fascinated about this topic, I started my studies of biology at the Paris-Lodron University in Salzburg (Austria). During my studies, I got more and more interested in microbiology and how it is possible for microbes to survive in the most extreme environments on earth. At the end of my studies I first heard the term "Astrobiology" during a course with Prof. Stan-Lotter. Following some talks with Prof. Stan-Lotter I decided to write my diploma thesis on the topic: Survival of Halococcus dombrowskii H4 under extreme environmental situations including those of the martian atmosphere.
After finishing my thesis, I got in contact with the Australian Centre for Astrobiology and with one of the members, Assoc. Prof. Brett Neilan from the University of New South Wales. After winning an international Macquarie University Scholarsip (iMURS) award, I arrived in February 2004 in Sydney to start my PhD under the supervision of Prof. Malcolm Walter and Assoc. Prof. Brett Neilan.
At the moment I am working at UNSW, in the lab of Dr. Brett Neilan, on my PhD thesis. My thesis focusses on the mechanisms of halophilic archaea to survive low/high salt stress. Halophilic archaea need up to 20% NaCl to grow, but they can survive and grow in much higher concentrations, up to NaCl saturation.
Another topic is the diversity of microbes in the living stromatolites in Shark Bay. These stromatolites are mostly formed by cyanobacteria but little is known about the diversity in these laminated structures. At the moment I am trying to investigate the diversity with RISA (Ribosomal intergenic spacer analysis) - patterns and apply this method directly to environmental samples from Shark Bay. By investigating the diversity of halophilic archaea in these stromatolites, we hope to gain significant data about early life on Earth.
Publications:
Publications 2005 -2006:
Book Chapters:
Leuko, S. , Legat, A., Fendrihan, S., Wieland, H., Radax, C., Gruber, C., Pfaffenhuemer, M., Weidler, G., Stan-Lotter, H. (2005). Isolation of viable haloarchaea from ancient salt deposits and application of fluorescent stains for in situ detection of halophiles in hypersaline environmental samples and model fluid inclusions. In: Cellular Origins, Life in Extreme Habitats and Astrobiology (COLE), edited by Seckbach J. Vol. 9, Adaptations to Life at High Salt Concentrations in Archaea, Bacteria and Eukarya. Gunde-Cimerman N, Oren A, Plemenitas A (eds.), pp. 91 - 104, Springer Verlag, Heidelberg, New York.
Stan-Lotter, H., Leuko, S., Legat, A., Fendrihan, S. The assessment of the viability of halophilic microorganisms in natural communities. In: Methods in Microbiology. Extremophiles. Oren, A., Rainey, F. (Eds). Elsevier, Oxford (in press).
Stan-Lotter, H., Radax, C., Leuko, S., Legat, A., Gruber, C., Pfaffenhuemer, M., Wieland, H., Weidler, G. (2005). Viable halobacteria from ancient oceans - and in outer space? In: Life in the Universe. From the Miller Experiment to the Search for Life on Other Worlds. Series: Cellular origin and life in extreme habitats and astrobiology, Vol. 7. Seckbach, J., Chela-Flores, J., Owen, T., Raulin, F. (Eds), pp. 207-210, Springer Verlag, Heidelberg.
Journal Papers:
F. Goh, S.Leuko, M.A. Allen, J.P. Bowman, M. Kamekura, B.A. Neilan and B.P. Burns
Halococcus hamelinii sp. nov., a novel halophilic archaeon isolated from stromatolites in Shark Bay, Australia.(2006) Int. Syst. Evol. Microbiol, in press.
Craig P. Marshall, Elizabeth A. Carter, S. Leuko, and Emmanuel J. Javaux. Vibrational Spectroscopy of extant and fossil microbes: Relevance for the astrobiological exploration of Mars. Journal of Vibrational Spectroscopy. In press
Conference Proceedings:
S. Leuko , B. P. Burns, M. Walter and B. A. Neilan (2005) Adaptation of Halobacterium salinarum NRC-1 to different salt concentrations. IUMS 2005. Microbes in a Changing World, San Francisco, July 2005, Poster Presentation
Stan-Lotter, H., A. Legat, A., Pfaffenhuemer, M., Gruber, C., Fendrihan, S., Weidler, G., Leuko, S., Radax, C., Busse, H.-J. 2005. Remnants from ancient oceans - viable haloarchaea in rock salt. IUMS 2005. Microbes in a Changing World, San Francisco, July 2005, Abstr. 204B (Symposium).Stan-Lotter, H., Fendrihan, S., Leuko, S., Legat, A., Gruber, C., Pfaffenhuemer, M., Weidler, G., Busse, H.-J. (2005) Survival of halobacteria (haloarchaea) in fluid inclusions as a model of biotic survival in subterranean and extraterrestrial halite. Abstr. EGU05-A-09129, European Geosciences Union General Assembly, April 2005, Vienna, Austria.
In 2004:
S.Leuko, A. Legat, S. Fendrihan and H. Stan-Lotter. (2004) Evaluation of the LIVE/DEAD BacLight Kit for detection of extremophilic archaea and visualization of microorganisms in environmental samples. Appl. Environ. Microbiol. 70: 6884-6886.
Last Updated: Jan 30 2006