Bacteria growth laws

Enterobacter aerogenes, B. subtilis, P. fluorescens, and Serratia marces-cens produce acetoin by decarboxylation of a-acetolactate. However, yeasts and E. coli form acetoin from the acetaldehyde-TPP complex and free acetaldehyde (Rodopulo et al 1976). These organisms do not decarboxylate a-acetolactate, but use it to produce valine and pantothenic acid. In lactic acid bacteria, a-acetolactate is not used for valine or pantothenic acid synthesis, since these substances are required for growth (Law et al. 1976B Reiter and Oram 1962). In those microorganisms which can synthesize valine, this amino acid inhibits a-acetolactate synthesis (Rodopulo et al 1976). 

The growth of a bacteria Stepinpoopi can be described by die logistic growth law... 

The production of a product P from a particular gram negative bacteria follows the Monod growth law... 

Hence, sometimes phenomena associated with enzyme kinetics control the rate of biotransformations. If suitable enzymes are present in the microbial community, for example due to consumption of structurally related growth substrates, then we may see immediate degradation of compounds of interest like BQ when they are added to these metabolically competent microbial communities (Fig. 17.17). For such cases, if the abundance of the bacteria is varied, the rate of removal changes accordingly. Consequently, the removal of BQ could be described by a second-order rate law (Smith et al., 1978) ... 

Italy Since 1999 toxicity assays for effluents are required by law (order D.L. 152/99). The following tests are recommended - Acute toxicity test on Daphnia magna or Ceriodaphnia dubia - Algal growth inhibition test on algae Selenastmm capricomutum - Luminescence inhibition test on bacteria - Acute toxicity test on Artemia salina (for saline discharges)... 

From these considerations, Emerson (E3) concluded that growth of a fungal culture in liquid medium ought to follow a different law than does growth of bacteria. In particular, he concluded that, for batch growth. 

As long as growth follows the above law it is said to be logarithmic. In a vessel where fresh medium is continually supplied and old medium removed bacteria may be maintained in the logarithmic phase indefinitely, but in a static system one of two things happens either the supply of material becomes exhausted, or the concentration of inhibitory products formed by the bacterial reactions becomes too high. Growth then ceases and the cells enter what is usually called the stationary phase. 

The possibility of adaptation seems to follow clearly enough from the conclusion that the different enzyme systems obey the law of autocatalytic growth and that when the bacteria are cultured under constant conditions the amounts of the different enzymes settle down to steady ratios. The proportions depend upon the various reaction velocity constants. If something changes the constants, then the proportions should gradually change also. 

The growth rates of different bacteria obviously follow quite different time laws as far as both the shape and the timescale are concerned. The scheme of the growth development seems, however, to be the same for each bacterium independent of the degree of contamination. This allows identifying different bacteria from the shape of the heat production rate independent of the respective concentration of... 

Nutritional dependence on pterinoid antimetabolites is a fascinating phenomenon and part of the problem of resistance to the antifolics in cancer therapy. Law (1958) noted that some strains of mouse leukemia have become dependent on antifolics. Is the explanation like that for Neurospora If one had antifolio-dependent strains of protozoa and bacteria, analysis of their growth requirements might uncover new metabolites, as happened for streptomycin-dependent bacteria. 

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