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At least 181 records · Page 10Linked to original sources
PubMed2002

UV photochemistry of DNA in vitro and in Bacillus subtilis spores at earth-ambient and low atmospheric pressure: implications for spore survival on other planets or moons in the solar system.

Two major parameters influencing the survival of Bacillus subtilis spores in space and on bodies within the Solar System are UV radiation and vacuum, both of which induce inactivating damage to DNA. To date, however, spore survival and DNA photochemistry have been explored only at the extremes of Earth-normal atmospheric pressure (101.3 kPa) and at simulated space vacuum (10(-3)-10(-6) Pa). In this study, wild-type spores, mutant spores lacking alpha/beta-type small, acid-soluble spore proteins (SASP), naked DNA, and complexes between SASP SspC and DNA were exposed simultaneously to UV (254 nm) at intermediate pressure (1-2 Pa), and the UV photoproducts cis,syn-thymine-thymine cyclobutane dimer (c,sTT), trans,syn-thymine-thymine cyclobutane dimer (t,sTT), and "spore photoproduct" (SP) were quantified. At 101.3 kPa, UV-treated wild-type spores accumulated only SP, but spores treated with UV radiation at 1-2 Pa exhibited a spectrum of DNA damage similar to that of spores treated at 10(-6) Pa, with accumulation of SP, c,sTT, and t,sTT. The presence or absence of alpha/beta-type SASP in spores was partly responsible for the shift observed between levels of SP and c,sTT, but not t,sTT. The changes observed in spore DNA photochemistry at 1-2 Pa in vivo were not reproduced by irradiation of naked DNA or SspC:DNA complexes in vitro, suggesting that factors other than SASP are involved in spore DNA photochemistry at low pressure.

Atmospheric Pressure↗
PubMed2005

Experimental support for an immunological approach to the search for life on other planets.

We propose a three-phase approach to test for evidence of life in extraterrestrial samples. The approach capitalizes on the flexibility, sensitivity, and specificity of antibody-antigen interactions. Data are presented to support the first phase, in which various extraction protocols are compared for efficiency, and in which a preliminary suite of antibodies are tested against various antigens. The antigens and antibodies were chosen on the basis of criteria designed to optimize the detection of extraterrestrial biomarkers unique to living or once-living organisms.

Biomarkers↗
PubMed2001

Mars and Venus: unequal planets.

Self-help books, a pervasive and influential aspect of society, can have a beneficial or detrimental effect on the therapeutic process. This article describes a thematic analysis and feminist critique of the best-selling self-help book, Men are from Mars, Women are from Venus. This analysis revealed that the author's materials are inconsistent with significant family therapy research findings and key principles of feminist theories. His descriptions of each gender and his recommendations for improving relationships serve to endorse and encourage power differentials between women and men.

Books↗
PubMedDate not supplied

[Severe trauma rate during planet geomagnetic storms].

The growth of the diurnal frequency of appearance of heavy traumas during planetary geomagnetic storms is shown and statistically justified. No effect of short-term geomagnetic disturbances of natural and technogenic nature on the occurrence of acute mental and cardiovascular pathologies was detected on the basis of diurnal data.

Data Interpretation, Statistical↗
PubMed2000

Artificial biospheres as a model for global ecology on planet Earth.

Artificial biospheres of the scale and complexity of Biosphere 2 can only work with coordinated rigorous design at each level of ecology: biospheres, biomes, bioregions, ecosystems, communities, patches, phases, physical-chemical functions, guilds, populations, organisms, and cells (both eucaryotic and procaryotic). This article reviews these theoretical concepts and provides examples of how this structure was applied to the design and development of Biosphere 2. In addition to this ecological engineering design, the addition of humans as inhabitants in the closed system required design of ethnological patterns and of technical and cybernetic systems for meeting specifically human requirements of labor efficiency, climate, nutrition, wastewater recycle, and pure air and water. Ecological levels of biospheric complexity can be directly applied to studies of the Earth's biosphere and, in fact, must be used to understand complex biospheric processes.

Animals↗
PubMed1977

Life and the outer planets. II. Enzyme activity in ammonia-water systems and other exotic media at various temperatures.

Enzyme activities are customarily measured in aqueous solutions. Activity and thermodynamic parameters are based upon behavior in these solutions although they in no way represent the highly structured internal surface system of the cell. Actual environmental limits for enzyme action may be greater than generally assumed. Peroxidase, catalase, urease and amylase retain activity in drastically modified aqueous and nonaqueous media, including aprotic solvents. Examples include formic acid, methanol, formamide, nitromethane, 10 M LiCl and 15 M aqueous ammonia. Temperatures as low as 225-233 degrees K permit activity in some media. Ammonia-rich environments are compatible with some forms of terrestrial life. Enzyme activity in these exotic media and conditions is relevant to chemical evolution on Jupiter and similar planetary systems.

Ammonia↗