The Astrobiology Research Activity at INAF-Osservatorio Astronomico di Palermo

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

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 × 109 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 AcidsIrradiation Experiments

Early X-ray and UV radiation

Origin of Life

A new facility (LEAB) for a more realistic scenario


Origin of LifeThe building blocks of life were built

Miller’s Experiment

Hp: Earth Atmosphere (NH3, CH4, H2 + H2O vapor)

+ Spark discarge

Res: many organic compounds including amino acids

However: 1) H rich atmosphere quickly lost2) N2, CO, CO2 and H2O inefficient for organic molecules

on the Earth

UV H2O, CO, CO2, CH3OH, NH3

GlycineAlanineValine Serine

Proline ….. (Muñoz-Caro et al.; Bernstein et al. Nat. 2002)

Murchison Miller

?Many open questions: Experiment & Results Why just UV?Amino Acids high photo-distruction rateProtection mechanisms

Organic molecules are in:

▪ Interstellar clouds

▪ Micrometeorites (0.01 – 0.1mm) today: 50- 100 tons/day

▪ Meteorites (+ amino acids)

Heavy bombardment by comets, meteorites and micrometeorites main carriers of organic material

4.2 - 3.9 × 109 yr ago = 103× today value

in space


Sun

@ m

inSu

n @

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 photons @ Earth were >103 higher than today when the Sun was only 108 yr old.

Early X-ray Sun: more active, hard and bright …but today is a modest X-ray source (LX = 1027 – 1030 erg/sec)


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

LX = 1031 – 1033 erg/sec


X-ray Irradiation of DNA

Free

Clay Ads.

Al 1.49 0.15 Ti 4.51 0.17 Cu 8.04 0.20

(erg sec-1 cm -2 )(keV )

Irradiation Dose : 102 - 5.8 × 104 erg

10-5 minimum 8 months 3 × 10-3 maximum 19 hours 10-1 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.)


X-ray Irradiation of Amino Acids

Tryptophan C11H12N2O2

ppm (t1)0.01.02.03.04.05.06.07.08.0

0

500

1000

1500

2000

1.00

1.03

1.00

1.00

1.01

3.07

-0.0

0

tri000 in D20

NH2

NH

COOH

HaHb1

Hb2

H2

H4H5

H6H7

ppm (t1)0.01.02.03.04.05.06.07.08.0

0

10

20

30

40

7.6167.5907.4207.3937.1797.1547.1297.0937.0677.043

4.962

3.9333.9173.9073.8913.4283.4113.3853.3693.3343.318

3.2533.2043.1773.1533.126

1.968

1.0951.0731.0571.036

0.0380.015

-0.051

tri 005 D2O "overdose of X"

H2NCHC

CH2

OHO

HN

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)


The LEAB Facility: Why? Simulate space conditions :

● A cold finger with T=10 -300 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 (~10-11 mbar) oil-free vacuum pumping systems

● Mass spectrometer system up to 200 amu

IR Spectroscopy

UV

X-ray

Mas

s Sp

ectro

met

er

~ 80 k€


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 acids2) Synthesis of amino acids inside cavities

The Past, Ongoing and Future Experimental Plan

Spring-Summ

er 2008E

nd 2008-2009


Sources of funds: ● Local Obs. (Director) (main source! ~ 70 k€ )● PRIN-INAF 2006 - 60k€ ( 50 k€ OAPA; ~20 k€ lab.) ● ASI call “Nuove Tecnologie e Spin-in: selezione di idee” Nov. 2006 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

Documents

The Astrobiology Research Activity at INAF-Osservatorio Astronomico di Palermo