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At least 1,099 records · Page 61Linked to original sources
PubMed1994

Oligonucleotides as probes for studying polymerization reactions in dilute aqueous solution.

We have prepared a [32P]-labled oligonucleotide probe carrying a free primary amine at its 3'-terminus. This probe is used to initiate polymerization of aziridine (ethyleneimine) in aqueous solution. The nature of the oligomeric products and the kinetics of their formation are then monitored by gel electrophoresis. Our results are generally consistent with those obtained using conventional techniques. We have also investigated the effect of polyanionic templates on the rate of oligomerization of aziridine. We find that water-soluble polyanions generally accelerate the polymerization. The sodium salt of polymethacrylic acid is the most effective of the templates that we studied. The methods introduced in this paper should be applicable to a variety of polymerization reactions in aqueous solution. They should greatly simplify the screening of potentially prebiotic polymerization reactions.

Autoradiography↗
PubMed1992

Polycondensation reactions of certain biologically essential molecules on mineral surfaces.

Methods of detecting extraterrestrial forms of organic matter should take into account the results of research in the effects of irradiation on the synthesis of biopolymers. Processes occurring on clay mineral surfaces and on the surfaces of minerals of different kinds are illustrated and the possible role of clays in prebiological evolution is discussed.

Aluminum Silicates↗
PubMed1992

Hydrogen cyanide polymerization: a preferred cosmochemical pathway.

Current research in cosmochemistry shows that crude organic solids of high molecular weight are readily formed in planetary, interplanetary and interstellar environments. Underlying much of this ubiquitous chemistry is a low energy route leading directly to the synthesis of hydrogen cyanide and its polymers. Evidence from laboratory and extraterrestrial investigations suggests that these polymers plus water yield heteropolypeptides, a truly universal process that accounts not only for the past synthesis of protein ancestors on Earth but also for reactions proceeding elsewhere today within our solar system, on planetary bodies and satellites around other stars and in the dusty molecular clouds of spiral galaxies. The existence of this preferred pathway - hydrogen cyanide polymerization - surely increases greatly the probability that carbon-based life is widespread in the universe.

Amino Acids↗
PubMed1992

What makes a planet habitable, and how to search for habitable planets in other solar systems.

The availability of liquid water is the most important factor that makes a planet habitable, because water is a very effective polar molecule and hence an excellent solvent and facilitator for the complex chemistry of life. Its presence presupposes a planet with a significant mass that guarantees the presence of a substantial atmosphere, and a reasonable spinning rate to avoid overheating. It also implies that the planet is at moderate distances from its central star, a range that is called the Ecosphere or the Habitable Zone. Since the evolution of life to high intelligence seems to take billions of years, it requires also that the central star must be neither too massive, that will produce a lot of lethal UV radiation and will have too short a life-span to allow life to evolve, nor of very small mass which will be producing too feeble a radiation to sustain life. The detection of free Oxygen in the atmosphere of a planet is a very strong evidence for the presence of life, because Oxygen is highly reactive and would rapidly disappear by combining with other elements, unless it is continuously replenished by life as the by-product of the process of photosynthesis that builds food for life (sugars) from CO2 and H2O.

Atmosphere↗
PubMed1985

The search for extraterrrestrial life: recent developments. A report on IAU Symposium 112.

This paper is a report on the International Symposium "The Search for Extraterrestrial Life: Recent Developments" which was held in Boston, Massachusetts, USA, 18-21 June 1984. It was the first IAU Symposium organised by Commission 51 of the International Astronomical Union (IAU), and was co-sponsored by the IAF/IAA, COSPAR, ISSOL and IUBS. This report describes the highlights from the seven Sessions and two special events of the Symposium, which was attended by 145 participants from 18 countries and in which more than 50 invited and contributed papers were presented. It also discusses the future plans and activities of IAU Commission 51.

Astronomy↗
PubMed1998

Life's crucible.

Explore the source record for details and available documents.

Biological Evolution↗