Microorganisms travel

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... 

The flow stream then typically travels through a filter (preferably less than 2 p pore size) which may or may not be part of the pumping system. This component is necessary to remove particles that could damage the check valves of most pumps. Since microorganisms can grow in water, it is required that aqueous solutions be filtered before use. 

DNP is not likely to build up in fish from water. We do not know how long DNP remains in water. Chemical reactions do not remove DNP from soil under natural conditions. The loss of DNP from soil to the air due to evaporation is not important. The extent that DNP seeps into soil from rainwater depends on the properties of the soil. DNP may travel deeper into certain soils than others, especially soils that are not acidic. Groundwater from a few disposal sites contains DNP. DNP in soil is destroyed primarily by microorganisms. It may take between 4 and 80 days for the level of DNP in soil to decrease by half. You will find further information about the fate and movement of DNP in the environment in Chapter 5. 

By using theory and experimental results concerning particle deposition in porous media, predictions can be made of the removal of viruses, bacteria, and other microorganisms in aquifers. For a clean aquifer (i.e., one that has not received significant inputs of colloidal particles), the effects of particle size and surface chemistry on colloid transport are illustrated in Figure 11. The travel distance required to deposit 99% of the particles in a suspension (L99) is plotted as a function of the size (radius) of those particles for two chemical conditions. 

It Is easier to demonstrate synergy in vitro than in vivo, and concerns about the toxic contribution of the sulfonamide (and, doubtless, commercial considerations as well) have led to a recent vogue for the use of trimethoprim alone. Trimethoprim has a broad spectrum in vitro, so it Is potentially useful against many microorganisms. Combined with sulfamethoxazole, it Is used for oral treatment of urinary tract infections, shigellosis, otitis media, traveler s diarrhea, methicillin-resistant Staphylococcus aureus (MRSA), Legionella infection, and bronchitis. 

Halogenated hydroxyquinolines act on microorganisms in the intestinal tract and have been used for traveler s diarrhea. In Japan clioquinol (Vioform) has caused a subacute myelooptic neuropathy (SMON). The oral preparations have therefore been removed from the market in most countries. Clioquinol is still used topically and can cause contact dermatitis. A flare of contact dermatitis after oral intake has been reported (Leifer and Steiner 1951 Domar and Juhlin 1967 Ekelund and Moller 1969). 

---