Spores , bacterial, survival space

When considering how the evolution of life could have come about, the seeding of terrestrial life by extraterrestrial bacterial spores traveling through space (panspermia) deserves mention. Much is said about the possibility of some form of life on other planets, including Mars or more distant celestial bodies. Is it possible for some remnants of bacterial life, enclosed in a protective coat of rock dust, to have traveled enormous distances, staying dormant at the extremely low temperature of space and even surviving deadly radiation The spore may be neither alive nor completely dead, and even after billions of years it could have an infinitesimal chance to reach a planet where liquid water could restart its life. Is this science fiction or a real possibility We don t know. Around the turn of the twentieth century Svante Arrhenius (Nobel Prize in chemistry 1903) developed this theory in more detail. There was much recent excitement about claimed fossil bacterial remains in a Martian meteorite recovered from Antarctica (not since... 

Besides being desiccated and irradiated, microorganisms traveling in space will be exposed to space vacuum that can reach 10-14 pascal (a unit of pressure—100 Pa = 1 mbar).57 The result is extreme dehydration, and naked spores can survive for only days if exposed to space vacuum. Survival of spores is increased if they are associated with various chemicals such as sugars, or are embedded in salt crystals. Nicholson et al. (2000) discuss the various stresses that a microbial cell or spore would have to endure to survive interplanetary travel.58 They include the process that transports them out of Earth s atmosphere, such as volcanic eruptions and bolide impacts, long periods of transit in the cold of space, and atmospheric entry into a new planetary home. Spores have been shown to survive the shock conditions of a meteorite impact and the ultraviolet radiation and low temperature of space.59 It is clear that panspermia is possible and even probable if bacterial spores become embedded in rocks that are ejected from one planet and eventually enter the atmosphere of another. Bacterial... 

Bacterial spores have been deliberately taken into space, in particular spores of the bacterium Bacillus subtilis. Up to 70 per cent of the bacterial spores survive in the short term for approximately 10 days of exposure to space vacuum. The chances of survival in space are increased if the spores are embedded in chemical protection such as sugars, or salt crystals, or if they are exposed in thick layers. For example, 30 per cent of B. subtilis spores survived for nearly 6 years in space when embedded in salt crystals and 80 per cent survived in the presence of glucose. Bacillus subtilis spores in Dominican amber have remained viable for several million years. Transport to a friendly environment with a source of energy is all that is required for life to be seeded on this planet or the next. 

In the dormant spore state, endospores are resistant to a wide variety of chemical and physical stresses such as UV and gamma radiation, desiccation, temperature and pressure extremes, and attack by toxic agents (67-70). As they are resilient to most sterilization procedures, bacterial spores are used in several industries as biological indicators (71,72). Certain species can even survive the vacuum, extreme temperatures, and radiation of space (73,74), making them the focus of research concerning planetary protection, panspermia (transfer of life from one... 

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