MONOD theory

The relationship between nutrients and the growth of populations of microorganism can be described in three ways. The simplest theory is the one developed for organic-carbon-limited bacterial growth by Monod (1942) and popularised for application to phytoplankton by Dugdale (1967). In this MONOD theory, the rate of uptake of dissolved nutrient (per unit biomass) depends on ambient concentration S ... 

The Jacob-Monod theory predicts (or, more correctly, was based on) two kinds of control-deficient mutations. Mutations in the regulatory gene prevent formation of active repressor. Lack of a functional repressor leads to uncontrolled high-level expression of the structural... 

The Jacob-Monod theory therefore predicts two types of constitutive mutants, one unlinked to the operon and recessive, and the other adjacent to the operon and cis-dominant. It generated some surprise, then, when regulatory mutants of the histidine operon were found to fall into a total of six different chromosomal positions. 

Because of the crucial role of this enzyme in one of the most important bicxrhemical pathways in the cell, its allosteric properties have been studied extensively in solution. Interpretation of these studies in terms of the theory of allosteric enzymes led Monod and coworkers to conclude that ... 

The basic kinetic properties of this allosteric enzyme are clearly explained by combining Monod s theory and these structural results. The tetrameric enzyme exists in equilibrium between a catalytically active R state and an inactive T state. There is a difference in the tertiary structure of the subunits in these two states, which is closely linked to a difference in the quaternary structure of the molecule. The substrate F6P binds preferentially to the R state, thereby shifting the equilibrium to that state. Since the mechanism is concerted, binding of one F6P to the first subunit provides an additional three subunits in the R state, hence the cooperativity of F6P binding and catalysis. ATP binds to both states, so there is no shift in the equilibrium and hence there is no cooperativity of ATP binding. The inhibitor PEP preferentially binds to the effector binding site of molecules in the T state and as a result the equilibrium is shifted to the inactive state. By contrast the activator ADP preferentially binds to the effector site of molecules in the R state and as a result shifts the equilibrium to the R state with its four available, catalytically competent, active sites per molecule. 

From theories on cooperative enzymes proposed by Monod and co-workers [16] came the idea that channels could... 

Jacob, Monod, and Changeux proposed a theory of the function and action of allosteric enzymes. 

J. Monod, Continuous culture technique. Theory and applications, Ann. Inst. Pasteur Paris 1950, 79, 390-410. 

Bottom-up systems biology does not rely that heavily on Omics. It predates top-down systems biology and it developed out of the endeavors associated with the construction of the first mathematical models of metabolism in the 1960s [10, 11], the development of enzyme kinetics [12-15], metabolic control analysis [16, 17], biochemical systems theory [18], nonequilibrium thermodynamics [6, 19, 20], and the pioneering work on emergent aspects of networks by researchers such as Jacob, Monod, and Koshland [21-23]. 

Mo2] J. Monod (1950), La technique de culture continue theorie et applications, Annates de I lnstitute Pasteur 79 390-401. 

Monod, J., La Technique of Culture Continue Theorie et Applications, ... 

Monod, J. (1971). Chance andNecessity, transi. A. Wainhouse. New York, NY Knopf. Morowitz, H. J. (1999). A theory of biochemical organization, metabolic pathways, and... 

One such theory was put forward in 1965 by J. Monod, J. Wyman, and J. P, Changeux. A very simple version of it is as follows. Suppose that the enzyme molecule consists of two subunits, each one of which can occur in two distinct conformations, which... 

Monod (M12) made two improvements on the theory of M Kendrick and Pai. In the view of the latter authors, the essential process involved in growth may be represented as a chemical reaction... 

I. Monod, "La Technique de Culture Continue, Theorie et Applications," Ann. Inst. Pasteur, 79 390-410 (1950). 

The biosynthesis of a particular enzyme is itself an elaborate and complex process Involving several cellular components. The genetic information for any particular enzyme is carried in a stretch of DNA which is the structural gene for that protein. The pattern is transcribed in a strip of the messenger RNA that dictates the proper sequence of amino acids in the synthesis of the enzyme. Van Dedem and Moo-Young have made an interesting beginning into incorporation of the operon theory of Jacob and Monod into a kinetic model for enzyme syntheses [3]. Indeed even a relatively simple model leads to many unidentifiable kinetic constants. 

Janoschek R (1991) Theories on the origin of biomolecular homochirality. In Janoschek R (ed) Chirality - from weak bosons to the a-helix. Springer, Berlin, pp 18-33 Monod J (1970) Le Hasard et la Necessite - Essai sur la philosophie naturelle de la biologie moderne. Editions du Seuil, Paris... 

Imai. K. Analyses of oxygen equilibria of native and chemically modified human adult hemoglobins on the basis of Adair s stepwise oxygenation theory and the allosteric model of Monod. Wyman, and Changeux. Biochemistry 1973, 12. 798-807. 

The present-day theory of microbial growth kinetics stems from, and is still dominated by, Monod s formulation (1942, 1949) of the function fi = /x(s), given in Equ. 2.54. Also, this relation is a homologue of the Michaelis-Menten equation Monod derived it empirically, and thus this is a formal kinetic equation. The consequence is a different interpretation of the parameters and K. The microbial growth rate is... 

In most cases of inhibition, the formal kinetic model equations are, like Monod s relationship, derived from theories of the inhibition of single enzymes. The equations are, however, only hypotheses they may be replaced by any other adequate model. 

While molecular biologists were investigating the structure of the molecules that store and serve to transfer specificity from DNA to protein, microbiologists investigated the spontaneous and induced mutations that occur in bacteria. Jacob and Monod used all the modern discoveries in molecular biology and bacterial genetics in a theory on the organization... 

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