[BAO01-P14] 火星生命探査に用いる蛍光色素の最適濃度検討
キーワード：火星、蛍光顕微鏡
In the Viking mission performed on Mars in 1970s, no appreciable organic compound was detected1). However, the detection sensitivity of organic compound of Viking TV-GC-MS was found to be too low to detect microbes in the area with low densitiy of microbes on Earth, such as Atakama dessert.
The Curiosity: Mars Science Laboratory (MSL) of NASA detected organic matter in the Gale Crater on Mars2). H2O ice was discovered in Phoenix mission3). The seasonal apparence of black lines on the slope of craters called Recurrent Slope Lineae (RSL) were obseved by Mars Reconnaissance Orbiter (MRO)4), which may be related some water activities. These suggest the possible presence of life on Mars.
Yamagishi and his colleagues have proposed a Mars exploration mission for in situ life detection by directly observing cells and organic matters in the soil on the surface of Mars with a fluorescence microscope5). The microscope was named as Life Detection Microscope (LDM). The LDM has the sensitivity 1000 times higher than that by Viking apparatus. We plan to use two fluorescent dyes, SYTO24 and Propidium Iodide (PI), in LDM. SYTO24 can be transported across the cell membrane and stains organic matter locating both outside and inside of cells. PI can not be transported across the cell membrane nor can stain in side of cells. By using these two dyes, it is possible to judge the presence or absence of organic matter and whether the latter be the living or dead cells.
We have dettermined the optimum concentrations of PI and SYTO 24 for LDM and report our progress on the development of LDM.
1) Navarro-Ginzalez, R., et al.,2006, PNAS, 103: 16089-16094. 2) Freissient, C., et al.,2015, J. Geophys. Res. Planets. 120: 495-514. 3) Feldoman, W.C., et al., 2002. Science, 297, 75-78. 4) Alfred S. McEwen, et al., 2011, Science, 333: 740-743. 5) Yamagishi, A., et al., 2010, Bio. Sci. Space. 24: 67-82
The Curiosity: Mars Science Laboratory (MSL) of NASA detected organic matter in the Gale Crater on Mars2). H2O ice was discovered in Phoenix mission3). The seasonal apparence of black lines on the slope of craters called Recurrent Slope Lineae (RSL) were obseved by Mars Reconnaissance Orbiter (MRO)4), which may be related some water activities. These suggest the possible presence of life on Mars.
Yamagishi and his colleagues have proposed a Mars exploration mission for in situ life detection by directly observing cells and organic matters in the soil on the surface of Mars with a fluorescence microscope5). The microscope was named as Life Detection Microscope (LDM). The LDM has the sensitivity 1000 times higher than that by Viking apparatus. We plan to use two fluorescent dyes, SYTO24 and Propidium Iodide (PI), in LDM. SYTO24 can be transported across the cell membrane and stains organic matter locating both outside and inside of cells. PI can not be transported across the cell membrane nor can stain in side of cells. By using these two dyes, it is possible to judge the presence or absence of organic matter and whether the latter be the living or dead cells.
We have dettermined the optimum concentrations of PI and SYTO 24 for LDM and report our progress on the development of LDM.
1) Navarro-Ginzalez, R., et al.,2006, PNAS, 103: 16089-16094. 2) Freissient, C., et al.,2015, J. Geophys. Res. Planets. 120: 495-514. 3) Feldoman, W.C., et al., 2002. Science, 297, 75-78. 4) Alfred S. McEwen, et al., 2011, Science, 333: 740-743. 5) Yamagishi, A., et al., 2010, Bio. Sci. Space. 24: 67-82