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Volume 22 (2008)
- Issue 4 Pages 141-
- Issue 3 Pages 93-
- Issue 2 Pages 41-
- Issue 1 Pages 3-
Volume 22, Issue 1
Displaying 1-3 of 3 articles from this issue
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Nobuo Suzuki, Katsunori Omori, Masahisa Nakamura, Makoto J. Tabata, Mi ...2008 Volume 22 Issue 1 Pages 3-7
Published: 2008
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSFish scale is a calcified tissue which is similar to those found in human bones. Recently, we developed a scale culture system in which osteoblasts and osteoclasts remain intact after being prepared. Using this system, we analyzed the bone metabolism under 2-, 4-, and 7-gravity (G) loading by centrifuge and compared with control (1-G). After loading for 5 and 10 min, the scales were incubated for 6 and 24 h. The osteoblastic and osteoclastic activities were then measured. The osteoblastic activity significantly increased under 2- and 4-G loading. This activity increased remarkably under 7-G loading. On the other hand, we found that the osteoclastic activity significantly decreased under 2-G loading. Under 4-G loading, there was no significant difference between G-loaded scales and control scales. The osteoclastic activity tended to increase under 7-G loading. These results were similar to our previous study of acceleration by vibration. Bone consists of osteoblasts, osteoclasts, and bone matrix. In our culture system including bone matrix, osteoblasts and osteoclasts reacted precisely to G loading by centrifuge. Therefore, we strongly believe that our culture system is useful for the analysis of bone metabolism under G loading.View full abstractDownload PDF (1108K) -
Mayumi Arai, Kaori Tomita-Yokotani, Seigo Sato, Hirofumi Hashimoto, Ma ...2008 Volume 22 Issue 1 Pages 8-17
Published: 2008
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSThe growth of terrestrial cyanobacterium, Nostoc sp., on the Martian Regolith Simulant (MRS) and its vacuum tolerance were studied as one of our challenges in this century to inhabit Mars. The viability of the tested cyanobacteria was evaluated by microscopic observation after staining by fluorescein diacetate (FDA). The general terrestrial cyanobacterial lump collected from the ground showed a significantly high tolerance to a high vacuum environment (10-5 Pa) for over one year. To scientifically elucidate its high tolerance function, Nostoc sp. HK-01 was used as another suitable scientific material for this study. After exposure to the high vacuum environment (10-5 Pa) for two weeks, Nostoc sp. HK-01 began to grow again. Some of it was also re-incubated again with a liquid culture medium. The A'MED (Arai's Mars Ecosystem Dome) is designed to be installed on Mars for agricultural production. A'MED was useful to conduct our study. We performed the fundamental experiment using the MRS. Nostoc sp. HK-01 was found to grow for over 140 days along with having the normal function of chlorophyll synthesis on the MRS. These results show the possibility that cyanobacteria could adapt to the MRS, and grow under the low pressure environment expected on Mars.View full abstractDownload PDF (1129K) -
Yinjie Yang, Shiho Itahashi, Shin-ichi Yokobori, Akihiko Yamagishi2008 Volume 22 Issue 1 Pages 18-25
Published: 2008
Released on J-STAGE: June 30, 2009
JOURNAL FREE ACCESSFive bacterial strains have been isolated from dust samples collected from the upper troposphere and lower stratosphere during several aircraft flights. Most of them displayed much higher resistance to ultraviolet radiation (254 nm) than surface airborne isolates. The role of UV radiation combined with other conditions to determine survivability of bacterial species in the upper atmosphere is discussed. Two strains from the upper atmosphere (ST0316 and TR0125) exhibited extreme UV resistance and tend to form cell clumps or aggregates. Forming cell aggregation might be a strategy to enhance their survivability in the harsh conditions such as high dosage of UV at high altitude.View full abstractDownload PDF (1411K)
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