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Angela Ciaravella Study the effects of X-ray radiation on biological molecules: DNA free and clay adsorbed in water solution Amino Acids in water solution.

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Presentation on theme: "Angela Ciaravella Study the effects of X-ray radiation on biological molecules: DNA free and clay adsorbed in water solution Amino Acids in water solution."— Presentation transcript:

1 Angela Ciaravella Study the effects of X-ray radiation on biological molecules: DNA free and clay adsorbed in water solution Amino Acids in water solution Since 2005 building the Laboratory for Experimental AstroBiology (LEAB) Astrobiology: interdisciplinary study of life in space, combining aspects of astronomy, biology and geology XACT The Astrobiology Research Activity at INAF-Osservatorio Astronomico di Palermo

2 A. Ciaravella –The Astrobiology Research Activity – Palermo 19/12/2007 Experimental Astrobiology at OAPA Effects of radiation on Organic molecules Life started on the Earth 3.8 – 4 × 10 9 yr Harsch radiation field Many uncertanties on the Earth atmosphere Synthesis of the building blocks of life UV + X-ray irradiation of ice analogoues DNA and Amino Acids Irradiation Experiments Early X-ray and UV radiation Origin of Life A new facility (LEAB) for a more realistic scenario

3 A. Ciaravella –The Astrobiology Research Activity – Palermo 19/12/2007 Origin of Life The building blocks of life were built Miller’s Experiment Hp: Earth Atmosphere (NH 3, CH 4, H 2 + H 2 O vapor) + Spark discarge Res: many organic compounds including amino acids However: 1) H rich atmosphere quickly lost 2) N2, CO, CO2 and H2O inefficient for organic molecules on the Earth UV H 2 O, CO, CO 2, CH 3 OH, NH 3 Glycine Alanine Valine Serine Proline ….. (Muñoz-Caro et al.; Bernstein et al. Nat ) MurchisonMiller ? Many open questions: Experiment & Results Why just UV? Amino Acids high photo-distruction rate Protection mechanisms Organic molecules are in: ▪ Interstellar clouds ▪ Micrometeorites (0.01 – 0.1mm) today: tons/day ▪ Meteorites ( + amino acids ) Heavy bombardment by comets, meteorites and micrometeorites main carriers of organic material × 10 9 yr ago = 10 3 × today value in space

4 A. Ciaravella –The Astrobiology Research Activity – Palermo 19/12/2007 min max X-ray Emission from Solar Type Stars:I ● X-ray emission fades much more rapidly than UV. ● The variations depends on the hardness of radiation: the hardest the fastest ( Micela 2002 ). ● In the 1-10 keV range, X Earth were >10 3 higher than today when the Sun was only 10 8 yr old. Early X-ray Sun: more active, hard and bright …but today is a modest X-ray source (L X = – erg/sec)

5 A. Ciaravella –The Astrobiology Research Activity – Palermo 19/12/2007 X-ray Emission from Solar Type Stars: II ● energetic radiation, very huge daily or weekly X-ray flares ( Feigelson \& Montmerle 1999;Feigelson et al. 2003) ● T Tauri show flares emitting at 8 keV for more than two day (Favata et al. 2005). Young Stars are Very Active in X-ray Very large flaring structures ( L » R* ) not found in more evolved star X-rays from the flare can heat up the planet- forming disk L X = – erg/sec

6 A. Ciaravella –The Astrobiology Research Activity – Palermo 19/12/2007 X-ray Irradiation of DNA Free Clay Ads. Al Ti Cu (erg sec -1 cm -2 ) (keV ) Irradiation Dose : × 10 4 erg minimum 8 months 3 × maximum 19 hours large flares 34 min The Sun today (1.5 –12.4 keV) (erg sec -1 cm -2 ) ⃟ ⃟ ⃟ Clay Adsorbed DNA is resistent Δ Δ Δ to the X-ray irradiation *** Free DNA is severely damaged by X-rays and the damage depends on the energy dose rather than the hardness of radiation (Ciaravella et al 2004,Int. J. Atrb.)

7 A. Ciaravella –The Astrobiology Research Activity – Palermo 19/12/2007 X-ray Irradiation of Amino Acids Tryptophan C 11 H 12 N 2 O 2 Preliminary Results  X-rays break the aliphatic chain:  Alanine  Alanine-Alanine peptide  UV (2780 Å) breaks the aromatic group  Solvent plays an important role (Ciaravella et al 2007, in prep)

8 A. Ciaravella –The Astrobiology Research Activity – Palermo 19/12/2007 The LEAB Facility: Why? Simulate space conditions : ● A cold finger with T= K ± 1 K ● A more realistic scenario for the synthesis of amino acids:  Not only UV HI Lya (usually used)  X-ray source (< 20 keV) (no used so far) more penetrating into protoplanetary disk and dust grains Multi-wavelength source quiete & flaring emission ● Big chamber (20 ×30 cm): allowing for many simultaneous diagnostics and irradiation sources High clean vacuum (~ mbar) oil-free vacuum pumping systems ● Mass spectrometer system up to 200 amu IR Spectroscopy UV X-ray Mass Spectrometer ~ 80 k€

9 A. Ciaravella –The Astrobiology Research Activity – Palermo 19/12/2007 X-ray & UV irradiation of Amino Acids in water solution X-ray irradiation of free & clay adsorbed DNA in water solution X-ray & UV irradiation of Amino Acids in icy mixtures Protection Survival Clays can protect DNA from X-ray & UV radiation Complexity Synthesis Amino acids in icy mixture implanted into different substrates ▪ Molecular complexity sustainable in space ▪ May radiation induce formation of more complex molecular structures 1) Synthesis of amino acids 2) Synthesis of amino acids inside cavities The Past, Ongoing and Future Experimental Plan Spring-Summer 2008 End

10 A. Ciaravella –The Astrobiology Research Activity – Palermo 19/12/2007 Sources of funds: ●Local Obs. (Director) (main source! ~ 70 k€ ) ●PRIN-INAF k€ ( 50 k€ OAPA; ~20 k€ lab.) ●ASI call “ Nuove Tecnologie e Spin-in: selezione di idee ” Nov proposal (selected) ●FP7_ITN (Initial Training Network) ) : COMIS: Complex Organic Molecules in Space : the first step toward understanding life in the Universe (selected) (1 Early Stage Researcher) ● FEBO: Facility for Exo-Biology Observations (ASI submitted) ● FP7_TNA (Trans National Activity) within Europlanet (in preparation) XACT + LEAB facilities Collaborations: ●C. Cecchi-Pestellini ( INAF-OACA) ● N. La Barbera, S. Giarrusso ( INAF-IASF) ●Chemists: (F. Mingoia; A. Venezia - CNR/INSM ) ●Biologists:(A. Puglia, M. Franchi, E. Gallori; Univ. Palermo & Firenze ) ●European scientists (Muñoz-Caro, Horneck, ……..) Funds & Collaborations


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