Energy and biological evolution—I. The equilibrium states of biochemical processes

1982 ◽  
Vol 44 (4) ◽  
pp. 501-535
Author(s):  
G. E. Tanyi
Keyword(s):  
Biological Evolution ◽  
Equilibrium States ◽  
Biochemical Processes

EQUILIBRIUM, STABILITY AND DYNAMICAL RESPONSE IN A MODEL OF THE EXTRINSIC APOPTOSIS PATHWAY

2007 ◽  
Vol 15 (03) ◽  
pp. 261-285 ◽  
Author(s):  
LUCIANO CAROTENUTO ◽  
VINCENZA PACE ◽  
DINA BELLIZZI ◽  
GIOVANNA DE BENEDICTIS
Keyword(s):  
Dynamical Behavior ◽  
Equilibrium Concentration ◽  
Equilibrium States ◽  
Model Parameters ◽  
Dynamical Response ◽  
Apoptosis Pathway ◽  
Biochemical Processes ◽  
Programmed Death ◽  
Dynamical Time ◽  
Extrinsic Apoptosis

In the past few years several mathematical models have been proposed to formally represent the biochemical processes that lead to the programmed death of the cell (apoptosis) starting from an intrinsic or extrinsic stimulus. In this paper we consider the model proposed by Eissing and colleagues in 2004 and, compared to the previously published results, provide several original contributions. We prove formally that the model can have one, two or three equilibrium states; one of these (the life equilibrium) represents the normal state of the cell: we state a stability criterion for this equilibrium and prove that its stability/instability is related to the number of equilibrium states. A large sample of models with randomly generated parameter vectors (representative of a population of cells) is numerically analyzed as regards both the equilibria and respective stability properties, and the dynamical behavior. Many patterns of stable/unstable equilibrium states, and different types of bifurcations are discovered. Correlations between model parameters, equilibrium patterns and equilibrium concentration of a critical protein are also carried out. The analysis of the dynamical time responses shows that the richness of behaviors accounted by the model is much larger than that implied by the classification into life-monostable, bistable, death-monostable models.

The Tempo and mode(S) of Prebiotic Evolution

1997 ◽  
Vol 161 ◽  
pp. 419-429 ◽  
Author(s):  
Antonio Lazcano
Keyword(s):  
Origin Of Life ◽  
Organic Compounds ◽  
Biological Evolution ◽  
Current Evidence ◽  
Early Diversification ◽  
Time Period ◽  
The Galaxy ◽  
History Of ◽  
Widespread Phenomenon ◽  
The Origin Of Life

AbstractDifferent current ideas on the origin of life are critically examined. Comparison of the now fashionable FeS/H2S pyrite-based autotrophic theory of the origin of life with the heterotrophic viewpoint suggest that the later is still the most fertile explanation for the emergence of life. However, the theory of chemical evolution and heterotrophic origins of life requires major updating, which should include the abandonment of the idea that the appearance of life was a slow process involving billions of years. Stability of organic compounds and the genetics of bacteria suggest that the origin and early diversification of life took place in a time period of the order of 10 million years. Current evidence suggest that the abiotic synthesis of organic compounds may be a widespread phenomenon in the Galaxy and may have a deterministic nature. However, the history of the biosphere does not exhibits any obvious trend towards greater complexity or «higher» forms of life. Therefore, the role of contingency in biological evolution should not be understimated in the discussions of the possibilities of life in the Universe.

3-D imaging of cells using a confocal laser scanning microscope and digital image processing

1988 ◽  
Vol 46 ◽  
pp. 96-97
Author(s):  
Thomas M. Jovin ◽  
Michel Robert-Nicoud ◽  
Donna J. Arndt-Jovin ◽  
Thorsten Schormann
Keyword(s):  
Laser Scanning ◽  
Confocal Laser Scanning Microscope ◽  
Laser Scanning Microscopy ◽  
Confocal Laser Scanning ◽  
Confocal Laser ◽  
Scanning Microscope ◽  
Laser Scanning Microscope ◽  
Biochemical Processes ◽  
Adjacent Structures

Light microscopic techniques for visualizing biomolecules and biochemical processes in situ have become indispensable in studies concerning the structural organization of supramolecular assemblies in cells and of processes during the cell cycle, transformation, differentiation, and development. Confocal laser scanning microscopy offers a number of advantages for the in situ localization and quantitation of fluorescence labeled targets and probes: (i) rejection of interfering signals emanating from out-of-focus and adjacent structures, allowing the “optical sectioning” of the specimen and 3-D reconstruction without time consuming deconvolution; (ii) increased spatial resolution; (iii) electronic control of contrast and magnification; (iv) simultanous imaging of the specimen by optical phenomena based on incident, scattered, emitted, and transmitted light; and (v) simultanous use of different fluorescent probes and types of detectors.We currently use a confocal laser scanning microscope CLSM (Zeiss, Oberkochen) equipped with 3-laser excitation (u.v - visible) and confocal optics in the fluorescence mode, as well as a computer-controlled X-Y-Z scanning stage with 0.1 μ resolution.

Macroeconomic Equilibrium Theory in the Context of Methodological Problems of Contemporary Economic Science

2008 ◽  
pp. 77-88
Author(s):  
M. Likhachev
Keyword(s):  
Empirical Analysis ◽  
Equilibrium States ◽  
Equilibrium Theory ◽  
Economic Systems ◽  
Economic Science ◽  
The Real ◽  
Theoretical Status ◽  
Methodological Problems ◽  
Real Stability

The article is devoted to the analysis of methodological problems in using the conception of macroeconomic equilibrium in contemporary economics. The author considers theoretical status and relevance of equilibrium conception and discusses different areas and limits of applicability of the equilibrium theory. Special attention is paid to different epistemological criteria for this theory taking into account both empirical analysis of the real stability of economic systems and the problem of unobservability of equilibrium states.

The essence of biological evolution

1984 ◽  
Vol 143 (7) ◽  
pp. 429 ◽  
Author(s):  
M.V. Vol'kenshtein
Keyword(s):  
Biological Evolution

The essence of biological evolution

1983 ◽  
Vol 141 (11) ◽  
pp. 546 ◽  
Author(s):  
M.V. Vol'kenshtein
Keyword(s):  
Biological Evolution
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