Bacteria sporulation

Microbial insecticides are very complex materials in their final formulation, because they are produced by fermentation of a variety of natural products. For growth, the bacteria must be provided with a source of carbon, nitrogen, and mineral salts. Sufficient nutrient is provided to take the strain of choice through its life cycle to complete sporulation with concomitant parasporal body formation. Certain crystalliferous bacilli require sources of preformed vitamins and/or amino acids for growth. Media for growing these bacilli may vary from completely soluble, defined formulations, usable for bench scale work, to rich media containing insoluble constituents for production situations (10,27). Complex natural materials such as cottonseed, soybean, and fish meal are commonly used. In fact, one such commercial production method (25) is based on use of a semisolid medium, a bran, which becomes part of the final product. 

Mycobacteria are more resistant than other non-sporulating bacteria to a wide range of biocides. Examples of such organisms axe Mycobacterium tuberculosis, theM avium-intracellulare (MAI) group andM. chelonae (M. chelonei). Of the bacteria, however, the most resistant of all to biocides are bacterial spores, e.g. Bacillus subtilis, B. cereus. 

Spore formation is limited almost entirely to two genera of rodshaped bacteria Bacillus (aerobic or facultatively anaerobic), and Clostridium (anaerobic or aerotolerant). With one possible exception, the common spherical bacteria do not sporulate. Some spore-bearing species can be made to lose their ability to produce spores. When the ability to produce spores is once lost, it is seldom regained. SporMation is not a process to increase bacterial numbers because a cell rarely produces more than one spore. 

PHAs are synthesized as intracellular energy and carbon storage materials. Therefore, bacterial cells with a high content of poly(3HB) are better able to survive than cells with a low poly(3HB) content [15]. Poly(3HB) also serves as an endogenous carbon and energy source for sporulation in Bacillus species and cyst formation in Azobacter species [16-18] and the majority of bacteria investigated accumulate PHAs in response to a nutrient limitation. The reported... 

Structurally, the sulfate reducing bacteria are pointed, non-mot ile rods, often associated in pairs. They are gram-negative and non-sporulating. These properties do not correspond with the... 

A striking accumulation of Mn2+ often occurs within bacterial spores (Chapter 32). Bacillus subtilus absolutely requires Mn2+ for initiation of sporulation. During logarithmic growth the bacteria can concentrate Mn2+ from 1 pM in the external medium to 0.2 mM internally during sporulation the concentrations become much higher.593... 

Sporulation. Bacteria of the genera Bacillus and Clostridium form metabolically inert spores when deprived of adequate nutrients (Fig. 32-1L83,203,20 1 Bacterial spores are remarkably resistant to heat and can survive boiling water for prolonged periods. 

More complex alternative developmental programs are followed by colonial forms of bacteria such as the myxobacteria. The life cycle involves aggregation of cells and formation of fruiting bodies as well as sporulation.185... 

Hoch, J. A. Control of cellular development in sporulating bacteria by the phosphorelay two-component signal transduction system. In, Two component signal transduction. Hoch, J.A., Silvay, T.J. eds., ASM Press Washington, D.C. 1995 pp. 129-144. 

Figure 8 Structures of nonmodified oligopeptide signal molecules mediating intraspecies cell-to-cell communication in Gram-positive bacteria, (a) Peptide sex pheromones and their inhibitors involved in the regulation of conjugative plasmid transfer in Enterococcus faecalis. (b) Competence- and sporulation-stimulating factors of Bacillus subtilis.

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