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Klein, H. P.

Publications and source records attributed to Klein, H. P..

At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Factors affecting the palmitoyl-coenzyme A desaturase of Saccharomyces cerevisiae

The activity and stability of the palmitoyl-coenzyme A (CoA) desaturase complex of Saccharomyces cerevisiae was influenced by several factors. Cells, grown nonaerobically and then incubated with glucose, either in air or under N2, showed a marked increase in desaturase activity. Cycloheximide, added during such incubations, prevented the increase in activity, suggesting de novo synthesis. The stability of the desaturase from cells grown nonaerobically was affected by subsequent treatment of the cells; enzyme from freshly harvested cells, or from cells that were then shaken under nitrogen, readily lost activity upon washing or during density gradient analysis, whereas aerated cells, in the presence or absence of glucose, yielded stable enzyme preparations. The loss of activity in nonaerobic preparations could be reversed by adding soluble supernatant from these homogenates and could be prevented by growing the cells in the presence of palmitoleic acid and ergosterol, but not with several other lipids tested.

Klein, H. P.↗
NASA NTRS1974

Automated life-detection experiments for the Viking mission to Mars

As part of the Viking mission to Mars in 1975, an automated set of instruments is being built to test for the presence of metabolizing organisms on that planet. Three separate modules are combined in this instrument so that samples of the Martian surface can be subjected to a broad array of experimental conditions so as to measure biological activity. The first, the Pyrolytic Release Module, will expose surface samples to a mixture of C-14O and C-14O2 in the presence of Martian atmosphere and a light source that simulates the Martian visible spectrum. The assay system is designed to determine the extent of assimilation of CO or CO2 into organic compounds. The Gas Exchange Module will incubate surface samples in a humidified CO2 atmosphere. At specified times, portions of the incubation atmosphere will be analyzed by gas chromatography to detect the release or uptake of CO2 and several additional gases. The Label Release Module will incubate surface samples with a dilute aqueous solution of simple radioactive organic substrates in Martian atmosphere, and the gas phase will be monitored continuously for the release of labeled CO2.

Klein, H. P.↗
NASA NTRS1972

Biological experiments - The Viking Mars Lander.

From the biological point of view, the Viking 1975 mission might be regarded as a test of the Oparin-Haldane hypothesis concerning the chemical evolution of living systems. Mars is a planet whose early history was probably similar to that of the earth and whose present environmental conditions may be compatible with the maintenance of living organisms. Thus, the biological experiments aboard the Viking I spacecraft are primarily concerned with the question of whether chemical evolution on Mars took place, and, if so, whether the process reached a level of complexity characteristic of replicating systems.

Klein, H. P.↗
NASA NTRS1972

Potential targets in the search for extraterrestrial life.

Discussion of the potential for increasing understanding of the origins of terrestrial life by examination of other planets. If living organisms should be found on another planet, they could only have been transported from an inhabited planet or originated independently. The fundamental chemical and structural attributes of terrestrial organisms are so remarkably uniform that any living forms outside the terrestrial blueprint would almost certainly be regarded as alien organisms. It has been shown experimentally by various investigators that life can exist in an extremely wide range of temperatures and pressures. The presence of an atmosphere appears to be necessary.

Klein, H. P.↗
NASA NTRS1972

Biological instrumentation for the Viking 1975 mission to Mars.

A brief introduction is given on why Mars is of interest from a biological point of view, along with an overview of the Viking 1975 mission. Details are given about the four biology instruments aboard the spacecraft and the experiments for which they are to be used. These are: the carbon assimilation experiment to determine whether the soil is biologically active; the label release experiment to detect metabolic activity by the release of radioactive CO2 from C-14 labelled simple organic substrates; the gas exchange experiment to detect biological activity by repeated gas chromatography analysis of soil samples; and the light scattering experiment, where increase of scattering and decrease of light transmission would indicate the growth of organisms. Examples are given of data obtained with terrestrial soils in these experiments.

Klein, H. P.↗
NASA NTRS1970

The coming search for life on Mars

Extraterrestrial life hypotheses, citing astronomical considerations, inorganic chemical evolution and prebiotic synthesis with emphasis on Mars exploration for microorganisms

Klein, H. P.↗