Exoplanetary Exoplanetary environments to harbour environments to harbour extremophile life as we extremophile life as we don´t know itdon´t know it
Claudia LAGEClaudia [email protected]@biof.ufrj.br
Instituto de Biofísica Carlos Chagas FilhoInstituto de Biofísica Carlos Chagas FilhoUniversidade Federal do Rio de Janeiro/BrazilUniversidade Federal do Rio de Janeiro/Brazil
1ASTROBIO 2010 Santiago, Jan 15
Outline
General surviving strategies to extreme environments found in micro-organisms
Deinococcus, a radiation survivor
Searching for new extremophiles on Earth
Concerns on the Panspermia connection with life as we don´t know it
1/ASTROBIO 2010 Santiago, Jan 15
3ASTROBIO 2010 Santiago, Jan 15
4ASTROBIO 2010 Santiago, Jan 15
The quest for perfect DNA duplication involves a protein complex
5ASTROBIO 2010 Santiago, Jan 15
Hyperthermophilic organisms mixed functions of an entire protein complex in a single protein
DNA primaseDNA helicaseDNA polymerase
Rossi et al., J Bacteriol, 2003
6ASTROBIO 2010 Santiago, Jan 15
Stronger surface charges cause hyperthermophilic proteins to stabilise complexes under higher temperatures
Archaeal PCNA
Yeast PCNA
7ASTROBIO 2010 Santiago, Jan 15
Low-temperature dependence for cold-loving species growth
8ASTROBIO 2010 Santiago, Jan 15
Membrane lipid structure in mesophilic organisms
Membrane lipid structure in cold-loving micro-organisms
Low-temperature adaption of cold-loving species membranes
9ASTROBIO 2010 Santiago, Jan 15
Solvent (concentration)log Pow
Staphylococcus sp. strain ZZ1
B. cereus strain ZZ2
B. cereus strain ZZ3
B. cereus strain ZZ4
Hexane 100 mM [1.3% (v/v)] 3.5 +++ +++ +++ +++
Cyclohexane 100 mM [1% (v/v)] 3.2 +++ +++ +++ +++
p-Xylene 100 mM [1.2% (v/v)] 3.0 +++ - ± -
Toluene 50 mM [0.53% (v/v)] 2.5 +++ +++ +++ +++
Toluene 100 mM [1% (v/v)] 2.5 +++ ± +++ +++
1-Heptanol 100 mM [1.4% (v/v)] 2.4 - - - -
Dimethylphthalate 100 mM [2% (v/v)] 2.3 +++ - +++ +++
Fluorobenzene 100 mM [1% (v/v)] 2.2 +++ +++ +++ +++
Benzene 100 mM [1% (v/v)] 2.0 +++ +++ +++ +++
Phenol 20 mM [0.18% (v/v)] 1.5 +++ - +++ +++
+++ growth overnight (16 h); ± minimal growth overnight; - no growth
Isolation and characterization of novel organic solvent-tolerant bacteria, Zahir et al. Extremophiles 2005 Oct
10ASTROBIO 2010 Santiago, Jan 15
Oceans of organic compounds are present in exoplanets and their moons... e.g. Titan
11 ASTROBIO 2010 Santiago, Jan 15
12ASTROBIO 2010 Santiago, Jan 15
ASTROBIO 2010 Santiago, Jan 15 13
ASTROBIO 2010 Santiago, Jan 15 14
They have been here since the beginning (chlorophyll-containing fossilisations in ~2,5Gyr Australian estromatolites)
15ASTROBIO 2010 Santiago, Jan 15
ORIGINS OF LIFE ON EARTHS
HOW CLOSE ARE WE TO MICRO-ORGANISMS?
STRESS RESPONSES ARE ALWAYS UP-TO-DATE!
Silicibacter sp.
Homo sapiens
ww
w.n
cbi.n
lm.n
ih.g
ov/B
LAST
/
17ASTROBIO 2010 Santiago, Jan 15
What´s up there in outer space?
No heat
No gases
No water
18ASTROBIO 2010 Santiago, Jan 15
ASTROBIO 2010 Santiago, Jan 15
Ejection Reentry
Transport
Density: 1 to 106 molecules.cm-3
Pressure > 10-17 atm
Radiation UV: 122.3 J.m-2.s-1
Temperature = 0 to hundreds K
Panspermia
19
ASTROBIO 2010 Santiago, Jan 15 1/
Horneck et al., Adv Space Res, 1994
Bacterial SPORES were shown to survive a 6-yr exposure to low Earth orbit radiation
21ASTROBIO 2010 Santiago, Jan 15
Mineral deposit on rockAvenca ???
Observation may be confusing in the search for life…
22ASTROBIO 2010 Santiago, Jan 15
23
24ASTROBIO 2010 Santiago, Jan 15
About Deinococcus...
ASTROBIO 2010 Santiago, Jan 15 25Deinococcus radiodurans
• The radiation constraint…
• 4Gy gamma rays to humans = • 15.000Gy gamma rays to
radiodurans
•
26ASTROBIO 2010 Santiago, Jan 15
SIMULATION EXPERIMENT IN THE SINCHROTRON LIGHT NATIONAL LABORATORY, Campinas, Brazil
CELL POWDER+
HIGH VACUUM+
WHITE BEAM VUV SOLAR RADIATION
1/ASTROBIO 2010 Santiago, Jan 15
28ASTROBIO 2010 Santiago, Jan 15
http://microbialgenomics.energy.gov/primer/featured_bugs.shtml
29ASTROBIO 2010 Santiago, Jan 15
ASTROBIO 2010 Santiago, Jan 15 30
ASTROBIO 2010 Santiago, Jan 15 31
Superfície microscópicada fita de carbono
MAUA 17 OUT 200932ASTROBIO 2010 Santiago, Jan 15
ASTROBIO 2010 Santiago, Jan 15
100µm
Morphologic comparison between surfaces of Concordia 2002 micrometeorite (Antartica) and that of the carbon tape on which bacterial powder was layered for irradiation (with permission of M. Maurette)..
CONCORDIA MICROMETEORITES CARBON TAPE
1/
ASTROBIO 2010 Santiago, Jan 15 34
ASTROBIO 2010 Santiago, Jan 15
Viability of Deinococcus radiodurans under shielding conditions
35
ASTROBIO 2010 Santiago, Jan 15
1/
Multiple secondary radiation effects enhance energy absorption by a large rock fragment
ASTROBIO 2010 Santiago, Jan 15
1/
Micro-sized particles have lower probability to interact with radiation
ATACAMA has life and you don´t see it
38ASTROBIO 2010 Santiago, Jan 15
0
5
10
15
20
25
30
35
40
45
50
Stromatolite Mats Mats Water table Well
Phylogenetic group
%
Alfa
Beta
Gamma
Cf
SRB
Arch
Eub
Sítio Maria Elena – Atacama - Chile
Marte
ASTROBIO 2010 Santiago, Jan 15 39
ASTROBIO 2010 Santiago, Jan 15
WATER ICE UPON MARS LANDING OF PHOENIX!!!
40
Searching for novel radiation resistant micro-organisms !!!
ASTROBIO 2010 Santiago, Jan 15 41
ASTROBIO 2010 Santiago, Jan 15
Growth curves after 300J.m-2 UV (single dose)
0,01
0,1
1
10
100
1000
0 3 6Days after UV
N/N
0
57
46
136-D
Growth curves of control cultures
0,01
0,1
1
10
100
1000
0 3 6 Days
N/N
o
57
46
136-D
UV (254nm) survival of bacterial isolates fromAntarctic samples
42
KOISTRA et al., 1958:
The behaviour of microorganisms under simulated Martian environmental conditions.
- low pressure chamber (0.06 mbar);
- soil samples from distinct geographic regions (in natura specific microflora);
- initial counts of colonies and after 1, 2 and 3 months under martian conditions;
- environmental “simulation” = cycles of 9h at 25oC, then 15h at -22oC.
Results:
ASTROBIO 2010 Santiago, Jan 15 43
ASTROBIO 2010 Santiago, Jan 15 44
Surface temperature estimates for some known exoplanets
• The surface temperature estimation depends not only on the stellar temperature but also e.g. on the planet's albedo and atmospheric chemical composition which will define the extent of the greenhouse effect and on how the heat is distributed around the planet
• The present sample of known exoplanets is strongly biased: e.g., long period planets are much more difficult to detect.
• Surface temperatures of the known exoplanets are on the average higher than for planets in the Habitable Zone (HZ)
ASTROBIO 2010 Santiago, Jan 15 45
– Surface temperatures of a number of Neptune-like planets have been estimated (e.g., Rivera et al. 2005, Bonfils et al. 2005; Bonfils et al. 2007; Demory et al. 2007)
– They are supposedly mainly composed of icy/rocky material, being formed without or having lost the extended gaseous atmosphere
– Some of them have orbital periods between 2 and 6 days and surface temperature ranges from 400 to 700 K
– Even in these particular cases, extremophiles existing on Earth (hyperthermophiles) could live even in the coldest of them
ASTROBIO 2010 Santiago, Jan 15 46
MOST FAVOURABLE KNOWN CASE:
Gliese 581c (Udry et al. 2007)
A 5 MEarth planet in the HZ of a MV (red) star
For Earth-like or Venus-like albedos, the surface temperature of Gliese 581c is estimated to range between
270 and 313 K, respectively.
Many extremophiles could live under these conditions!
ASTROBIO 2010 Santiago, Jan 15 47
INTERESTING POSSIBILITY: moons of planets in the HZ
Jupiter-like planets in the HZ: Examples:HD10697 (G5V ; 6.35 MJ, 1072 d orbit) TS 264 K
HD37124 (G4V ; 1.04 MJ, 155.7 d orbit) TS 327 K
HD134987 (G5V ; 1.58 MJ, 260 d orbit) TS 315 K
HD177830 (K2IV ; 1.22 MJ, 392 d orbit) TS 362 K
HD222582 (G3V ; ?? MJ, 576 d orbit) TS 234 K
Extremophiles could live “confortably” under these temperatures
ASTROBIO 2010 Santiago, Jan 15 48
SUMMARY OF KEY POINTS
The flux of solid material (large dust meteoroids) arriving on Earth from nearby stars was estimated in detail by Murray et al. (2004) from radar detections: ~ 10 yr-1·km-2; estimates on the amount of micro-sized material coming to Earth point to 10,000 TONS/YR !!!
We are presently located in an inter-arm (relatively low-density) region of the Galaxy. Each ~70 to 140 million years the solar system traverses a spiral arm region of much higher stellar and gas density. At each crossing of the Sun through a spiral arm, the flux of dust and gas of extra-solar origin arriving on top of terrestrial atmosphere will increase by many orders of magnitude.
The Panspermia hypothesis might thus be much more efficient. Microbes coming from other places in the CONTAMINATED GALAXY could use dust grains and micrometeorites as natural vehicles and benefit of the shielding effect operated by MICROPARTICULATE material. Living organisms could have more intensively seeded Earth during crossings of the solar system through dense galactic regions because of shorter times required for any organism to reach Earth.
ASTROBIO 2010 Santiago, Jan 15 49
IN CONCLUSION,
Micro-organisms could function as “minimal” biological organization spreading life in many planetary systems.
Microbial life could give birth to complex life, upon reaching a minimally viable planet/moon.
The ability of extremophile organisms to cope with environmental conditions far beyond conceivable limits should broaden the astronomical concept of HABITABLE ZONE to a biological one, the EXTREMOPHILE ZONE (EZ).
B
Brazilian team:
MSc Ivan PAULINO-LIMADr. João Alexandre R. G. BARBOSA1
Dr. Arnaldo Naves de BRITO1
Prof. Dr. Eduardo JANOT-PACHECO3
Dr Douglas GALANTE3
Gabriel DALMASO
1Laboratório Nacional de Luz Síncrotron – MCT/CNPq 2Instituto de Física – IF/UFRJ3Departamento de Astronomia – IAG/USP
International co-operation:Dr. Nigel MASON, Open University, UKDr. Charles COCKELL, Open University, UKArmando AZUA-BUSTOS, Univ Católica Chile
SAB 03 set 200750ASTROBIO 2010 Santiago, Jan 15
KEEP WATCHING...
Absence of evidence is not evidence of absence
Considering the immense Universe and the infinity of time, it is a joy for me to share a planet and a time with you…
Carl Sagan
THANK YOU
1/ASTROBIO 2010 Santiago, Jan 15