Bacteria-like organisms

It is also likely that organisms similar to the archaea (Section 3.2), bacteria-like organisms but with distinct rRNA characteristics, were ancestors of the bacteria and were the first organisms to fix carbon biologically. Members of the archaea are today found in extreme environments, such as deep-ocean vents and hydrothermal environments, which would have been more widespread in the early days of planet Earth and they persist reducing conditions with no oxygen. The biochemical reactions developed by such organisms may eventually have led to... 

This method depends on the fact that bacteria like all living organisms produce heat when they metabolize. Because of the small amount of heat produced, especially sensitive calorimetric devices are required hence the name microcalorimetry. The specimen to be evaluated is diluted with a nutrient medium and, if microorganisms are present and can metabolize, heat is produced and can be measured. An interesting offshoot of this technique is the fact that differing organisms produce different heat outputs and this may provide a means of identification. Microcalorimetry may enable organisms to be detected and possibly identified in 3 hours. 

An examination of stored industrial water supplies showed that 98% of the contaminants were Gram-ne live bacteria other organisms isolated were MrcrococcMv spp., Cytophaga spp., yeast, yeast-like fungi and actinomycetes. 

The need for effective bactericides is greater today than at any time in history. The recognition that mycoplasma-like organisms and xylem-limited bacteria cause plant disease means that there are additional diseases that are amenable to control with antibiotic-like compounds. X-disease, pear decline, peach yellows, phony peach, and plum leaf scorch are a few examples of diseases on deciduous tree-fruit crops caused by phytopathogenic prokaryotes. 

As previously mentioned (p. 7), bacteria like S. oneidensis and G. metallireducens have the capacity to reduce insoluble Mn02 to soluble Mn + enzymatically by anaerobic respiration with a suitable electron donor in a direct process in which the respective organisms attach to the surface of the oxide. In the case of S. oneidensis, the electron donor may be lactate, pyruvate, formate or H2, but not acetate. The lactate and pyruvate are oxidized to acetate as end-product. Geobacter metallireducens can use butyrate, propionate, lactate and acetate as electron donors, but not H2 or formate, and oxidizes the organic electron donors completely to CO2 and H2O. Geobacter sulfurreducens can use H2 as electron donor in Mn02 reduction (see Lovley, 2000). 

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