Growth and Metabolism

Growth and metabolism depends on the availability of water as microorganisms take up the nutrients present in water and produce cell material (51). Under favorable conditions, some bacteria can double in number every 20 min or less. Thus a single bacterium can produce a mass of over a million microorganisms in 7 h. The bacteria can survive from -10 to 100°C, pH 0-10.5, dissolved oxygen 0 to saturation, pressure of vacuum to 31 MPa, and a salinity of ppb to 30%. Most of the bacteria encountered in corrosion grow best at 15-45 C and pH of 6-8 (41). 

A majority of these microorganisms can form extracellular polymeric materials known as polymer or slime. The slime helps glue the organisms to the surface, trap, concentrate nutrients as food for microbes and shields the organisms from biocides. 

The slime can also act as a diffusion barrier and change the concentrations of different elements and pH at the electrochemical interface (41). 

Juvenile-onset diabetes has to be treated by replacement insulin therapy. Insulin is a polypeptide in which a 21-amino-acid chain (A) is linked to a 30- 

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In addition to reproductive effects, fish exposed to endocrine disrupters may have a decreased response to stress or decreased growth and metabolism which can affect their ability to survive, or to defend themselves against predators. All of these factors can affect the ability of the species to survive and to reproduce itself in sufficient numbers to maintain the stocks on which our commercial and sport fisheries are based. Not all fish species will be equally susceptible to the effects of endocrine disrupters. Selective sensitivity to such effects, especially those affecting reproduction, may well lead to major changes in the flora and fauna of some of our major aquatic ecosystems as the balance between fish, mammals, invertebrates and plants, and between predators and prey, is destabilised... 

Medium Mixture of nutrient substanees required by eells for growth and metabolism. 

The thyroid gland, located in the base of the neck, exerts i key role on growth and metabolism. In contrast with that of some of the other endocrine glands, this control is effected Ihrough a pair of relatively simple molecules, thyroxine, and its close congener, triiodothyronine. Cases of thyroid deficien-cy (hypothyroidism) are common enough to warrant the production... 

The stoichiometry of growth and metabolism can also be described by elemental material balances. This approach can provide an insight into the potential of the organism for biomass or product production, and thus the scope for process improvement. 

This allows an assessment of the relative efficiencies of the biochemical pathways involved in microbial growth and metabolism. 

For type 3 processes, growth and metabolic activity reach a maximum early in the batch process cycle (Figure 3.1) and it is not until a later stage, when oxidative activity is low, that maximum desired product formation occurs. The stoichiometric descriptions for both type 3 and 4 processes depend upon the particular substrates and products involved. In the main, product formation in these processes is completely uncoupled from cell growth and dictated by kinetic regulation and activity of cells. 

Cell growth and metabolic activities are similarly described as a simple chemical reaction. It is also necessary to establish a definite formula for dry cell matter. The elemental composition of certain strains of microorganism is defined by an empirical formula CHaO/3Ns. The general biochemical reaction for biomass production is based on consumption of organic substrate, as shown below. Substrate oxidation is simplified in the following biochemical oxidation ... 

Wullschleger S, Loewith R, Hall MN (2006) TOR Signaling in growth and metabolism. Cell 124 471-484... 

Only two decades ago researchers started to study the effect of nutrient concentration on cell growth and metabolism systematically and the effect of pro-... 

Manganese and iron oxidation are coupled to cell growth and metabolism of organic carbon. Microbially deposited manganese oxide on stainless and mild steel alters electrochemical properties related to the potential for corrosion. Iron-oxidizing bacteria produce tubercles of iron oxides and hydroxides, creating oxygen-concentration cells that initiate a series of events that individually or collectively are very corrosive. 

In natural ecosystems, microbial growth and metabolism may be limited by the concentrations of inorganic nutrients such as nitrogen, phosphorus, or even iron. Systematic investigation of these... 

Filip Z, Haider K, and Martin JP (1972) Influence of clay minerals on growth and metabolic activity of Epicoccum nigrum Stachbotrys chartarum. Soil Biol Biochem 4 135-145... 

Elevated accumulations occur in aquatic plants during exposure to 100 pg/L and in fish during exposure between 1 and 13 pg/L. All species in these groups, however, seemed unaffected by elevated body burdens, as judged by normal growth and metabolism. 

McKenney, C.L., Jr. D.E. Weber, D.M. Celestial, and M.A. MacGregor. 1998. Altered growth and metabolism of an estuarine shrimp (Palaemonetes pugio) during and after metamorphosis onto fenvalerate-laden sediment. Arch. Environ. Contam. Toxicol. 35 464-471. 

Thyroid A gland located near the windpipe (trachea) that produces thyroid hormone, which helps regulate growth and metabolism. [NIH]... 

Microbial activity requires energy, and all microorganisms generate energy. This energy is subsequently stored as adenosine triphosphate (ATP), which can then be utilized for growth and metabolism as needed, subject to the second law of thermodynamics [2,23,35,41,42,51,54]. 

Oremland RS, Blum JS, Culbertson CW, et al. 1994. Isolation, growth, and metabolism of an obligately anaerobically, selenate-respiring bacterinm, strain SES-3. Appl Environ Microbiol 60 3011-9. 

Generally, in plant cells well supplied with O2, energy is provided for growth and metabolism by the oxidation of glucose in the three stages shown in Figure 6.1 ... 

Maynard, A.I., The influence of magnesium ions on the growth and metabolism of Saccharomyces cerevisiae, PhD thesis, Dundee Institute of Technology, 1993. 

Ratledge, C., Biochemistry of growth and metabolism, in Bu Lock, J.D. and Kristiansen, B., (eds.), Basic biotechnology. Academic Press, London, 1987. 

Biotin cannot be synthesized by mammals. The contribution of the biotin synthesized by intestinal bacteria to the hnman reqnirements is still controversial. Biotin is an essential cofactor for carboxylases involved in prodnction of fatty acids, cell growth, and metabolism of fats and amino acids. 

Suspension systems can be operated in different modes batch, fed-batch, chemostat, and perfusion (Fig. 1). These operation modes differ basically in the way nutrient supply and metabolite removal are accomplished, which in turn determines cell concentration, product titer and volumetric productivity that can be achieved [8]. The intrinsic limitation of batch processes, where cells are exposed to a constantly changing environment, limits full expression of growth and metabolic potentials. This aspect is partially overcome in fed-batch cultures, where a special feeding strategy prolonges the culture and allows an increase in cell concentration to be achieved. In perfusion and chemostat processes nutrients are continuously fed to the bioreactor, while the same amount of spent medium is withdrawn. However, in perfusion cultures the cells are retained within the bioreactor, as opposed to continuous-flow culture (chemostat), which washes cells out with the withdrawn medium [9]. 

The engineered bioremediation system (EBS) is a proprietary process for the ex situ bioremediation of organic contaminated soils. The system is designed to enhance the natural bioremediation rate of organic constituents by controlling factors affecting microbial growth and metabolism. 

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