scholarly journals Intrinsic noise modulation in closed oligomerization-type systems⋆

2018 ◽  
Author(s):  
Marianne Rooman ◽  
Fabrizio Pucci
Keyword(s):  
Molecular Species ◽  
Fano Factor ◽  
Type Systems ◽  
Intrinsic Noise ◽  
Individual Molecular Species ◽  
Intermediate States ◽  
The Individual ◽  
Random Fluctuations ◽  
Parameter Dependent ◽  
Oligomeric Product

AbstractHow random fluctuations impact on biological systems and what is their relationship with complexity and energetic cooperativity are challenging questions that are far from being elucidated. Using the stochastic differential equation formalism, we studied analytically the effect of fluctuations on a series of oligomerization processes, in which several molecules of the same or different species interact to form complexes, without interaction with the environment. The conservation of the total number of molecules within the systems imposes constraints on the stochastic quantities, among which the negativity of the covariances and the vanishing of the determinant of the covariance matrix. The intrinsic noise on the number of molecules of each species is represented by the Fano factor, defined as the variance to mean ratio. At the equilibrium steady states, the sum of the Fano factors of all molecular species is equal to the rank of the system, independently of the parameters. The Fano factors of the individual molecular species are, however, parameter dependent. We found that when the free energy cooperativity of the reactions increases, the intrinsic noise on the oligomeric product decreases, and is compensated by a higher noise on the monomeric reactants and/or intermediate states. The noise reduction is moreover more pronounced for higher complexity systems, involving oligomers of higher degrees.

Identification of the individual molecular species of ceramides derived from human erythrocytes using HPLC/MS and HPLC/MS/MS

2011 ◽  
Vol 66 (13) ◽  
pp. 1270-1275
Author(s):  
D. A. Korzhenevskii ◽  
V. N. Kuptsov ◽  
V. A. Mityanina ◽  
A. A. Selishcheva ◽  
S. V. Saveliev ◽  
...  
Keyword(s):  
Molecular Species ◽  
Human Erythrocytes ◽  
Individual Molecular Species ◽  
The Individual

scholarly journals Phospholipid molecular species composition of mouse liver nuclei. Influence of dietary n–3 fatty acid ethyl esters

1992 ◽  
Vol 287 (1) ◽  
pp. 237-240 ◽  
Author(s):  
R S Chapkin ◽  
L D Davidson ◽  
L A Davidson
Keyword(s):  
Species Composition ◽  
Molecular Species ◽  
Mouse Liver ◽  
Ethyl Esters ◽  
Safflower Oil ◽  
Molecular Species Composition ◽  
Individual Molecular Species ◽  
Phospholipid Molecular Species ◽  
Liver Nuclei ◽  
The Individual

The effect of dietary eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) ethyl esters on the individual molecular species composition of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) was determined in mouse liver nuclei. After a 10 day feeding period, there was a depletion of the sn-2 position of n-6 polyunsaturated fatty acids (PUFA) and substitution with n-3 PUFA. EPA feeding significantly increased (P less than 0.05) diacyl PC and PE 16:0-20:5, n-3, 16:0-22:6,n-3, 18:0-20:5,n-3 and 18:0-22:6,n-3 relative to control (safflower oil ethyl ester fed) animals. In comparison, DHA feeding significantly increased (P less than 0.05) 22:6 n-3-containing species, specifically 18:1-22:6,n-3, 16:0-22:6,n-3 and 18:0-22:6,n-3 in PC, and 18:1-22:6,n-3, 16:0-22:6,n-3 and 18:0-22:6,n-3 in PE. In addition, the presence of 18:0-20:5,n-3 PC in the nuclei of DHA-fed rats and of 18:2-20:5,n-3, 18:1-20:5,n-3 and 18:0-20:5,n-3 in nuclear PE indicate that incorporation of DHA retroconversion (22:6,n-3–>20:5,n-3) products. These results indicate both EPA and DHA are extensively incorporated into nuclear phospholipids, and therefore could potentially influence gene function.

Anti-Inflammatory Properties of Plant Derived Natural Products – A Systematic Review

2019 ◽  
Vol 26 (24) ◽  
pp. 4506-4536 ◽  
Author(s):  
Iris E. Allijn ◽  
René P. Brinkhuis ◽  
Gert Storm ◽  
Raymond M. Schiffelers
Keyword(s):  
Systematic Review ◽  
Natural Products ◽  
Positive Control ◽  
Therapeutic Effects ◽  
Reference Compound ◽  
Individual Molecular Species ◽  
The Past ◽  
Anti Inflammatory ◽  
The Individual ◽  
Natural Medicines

Traditionally, natural medicines have been administered as plant extracts, which are composed of a mixture of molecules. The individual molecular species in this mixture may or may not contribute to the overall medicinal effects and some may even oppose the beneficial activity of others. To better control therapeutic effects, studies that characterized specific molecules and describe their individual activity that have been performed over the past decades. These studies appear to underline that natural products are particularly effective as antioxidants and anti-inflammatory agents. In this systematic review we aimed to identify potent anti-inflammatory natural products and relate their efficacy to their chemical structure and physicochemical properties. To identify these compounds, we performed a comprehensive literature search to find those studies, in which a dose-response description and a positive control reference compound was used to benchmark the observed activity. Of the analyzed papers, 7% of initially selected studies met these requirements and were subjected to further analysis. This analysis revealed that most selected natural products indeed appeared to possess anti-inflammatory activities, in particular anti-oxidative properties. In addition, 14% of the natural products outperformed the remaining natural products in all tested assays and are attractive candidates as new anti-inflammatory agents.

Research on the Pressure-Measuring Uncertainty of Standard Internal Crusher Gauge

2013 ◽  
Vol 300-301 ◽  
pp. 874-881
Author(s):  
Chuan Rong Zhao ◽  
De Ren Kong ◽  
Fang Wang ◽  
Li Xia Yang ◽  
Li Ping Li
Keyword(s):  
Theoretical Foundation ◽  
Evaluation Model ◽  
Computing Methods ◽  
Selection Methods ◽  
Pressure Source ◽  
True Value ◽  
Individual Character ◽  
Copper Cylinder ◽  
The Individual ◽  
Random Fluctuations

This article introduces the function, the method of selection and related criterion of standard internal crusher gauge, and systematically analyzes three factors that affect the measuring uncertainty of standard internal crusher gauge, including: inconsistency of pressure’s true value from pressure source, the uncertainty imported by standard copper-cylinder and the random fluctuations of the individual character of pressure measuring gauge. According to usage characteristics and selection methods of the standard internal crusher gauge, discusses computing methods of components of the measuring uncertainty and establishes evaluation model for measuring uncertainty of standard internal crusher gauge. The model can quantitatively calculate through experimental data of selection, which lay a theoretical foundation for the control of the pressure measuring uncertainty of standard internal crusher gauge.

Condensation Reactions Synthesize Random Polymers

2019 ◽  
Author(s):  
David Ross
Keyword(s):  
Origin Of Life ◽  
Rna World ◽  
Functional Polymers ◽  
Peptide Bonds ◽  
Individual Molecular Species ◽  
Condensation Reactions ◽  
Past Half Century ◽  
Working Together ◽  
The Origin Of Life ◽  
The Individual

Over the past half century of serious research on the origin of life, several schools of thought have emerged that focus on “worlds” and what came first in the pathway to the origin of life. One example is the RNA World, a term coined by Walter Gilbert after the discovery of ribozymes. Other examples include the Iron-Sulfur World of Günther Wächtershäuser and the Lipid World proposed by Doron Lancet and coworkers. Then we have a competition between “metabolism first” and “replication first” schools. The worlds and schools have the positive effect of sharpening arguments and forcing us to think carefully, but they also can lock researchers into defending their individual approaches rather than looking for patterns in a larger perspective. One of the main themes of this book is the notion that the first living cells were systems of functional polymers working together within membranous compartments. Therefore, it is best not to think of “worlds” and “firsts” as fundamentals but instead as components evolving together toward the assembly of an encapsulated system of functional polymers. At first the polymers will be composed of random sequences of their monomers, and the compartments will contain random assortments of polymers. Here, we refer to these structures as protocells which are being produced in vast numbers as they form and decompose in continuous cycles driven by a variety of impinging, free-energy sources. This chapter describes how thermodynamic principles can be used to test the feasibility of a proposed mechanism by which random polymers can be synthesized. There is a current consensus that early life may have passed through a phase in which RNA served as a ribozyme catalyst, as a replicating system, and as a means for storing and expressing genetic information. For this reason, we will use RNA as a model polymer, but condensation reactions also produce peptide bonds and oligopeptides. At some point in the evolutionary steps leading to life, peptides and RNA formed complexes with novel functional properties beyond those of the individual molecular species.

scholarly journals Molecular structural diversity of mitochondrial cardiolipins

2018 ◽  
Vol 115 (16) ◽  
pp. 4158-4163 ◽  
Author(s):  
Gregor Oemer ◽  
Katharina Lackner ◽  
Katharina Muigg ◽  
Gerhard Krumschnabel ◽  
Katrin Watschinger ◽  
...  
Keyword(s):  
Molecular Species ◽  
High Performance ◽  
Biological Diversity ◽  
Structural Diversity ◽  
Fatty Acyl ◽  
Model Organisms ◽  
Specific Class ◽  
Accurate Identification ◽  
Individual Molecular Species ◽  
Mass Spectral

Current strategies used to quantitatively describe the biological diversity of lipids by mass spectrometry are often limited in assessing the exact structural variability of individual molecular species in detail. A major challenge is represented by the extensive isobaric overlap present among lipids, hampering their accurate identification. This is especially true for cardiolipins, a mitochondria-specific class of phospholipids, which are functionally involved in many cellular functions, including energy metabolism, cristae structure, and apoptosis. Substituted with four fatty acyl side chains, cardiolipins offer a particularly high potential to achieve complex mixtures of molecular species. Here, we demonstrate how systematically generated high-performance liquid chromatography-mass spectral data can be utilized in a mathematical structural modeling approach, to comprehensively analyze and characterize the molecular diversity of mitochondrial cardiolipin compositions in cell culture and disease models, cardiolipin modulation experiments, and a broad variety of frequently studied model organisms.

The Potential for Correlative and Multiple Labeling With Colloidal Particles of Differing Shapes

2000 ◽  
Vol 6 (S2) ◽  
pp. 318-319 ◽  
Author(s):  
R.M. Albrecht ◽  
D.A. Meyer
Keyword(s):  
Molecular Species ◽  
Colloidal Particles ◽  
Imaging Systems ◽  
Staining Procedure ◽  
Individual Molecular Species ◽  
Imaging Technologies ◽  
Color Differences ◽  
Cell Components ◽  
Microscopic Studies

Labeling specific tissues, cells, cell components, or individual molecular species is often critical to correlative microscopic studies. In the case of larger structures such as tissues or cells it is often possible to use fluoresecent labels or cytologic/cytochemical based stains which are observable via photon based imaging systems. Specific locations on cells and tissues identified by the labeling or staining procedure can be delineated and then can be viewed via electron or force based instrumentation. This is provided preparative methodologies can be designed which: 1. are compatible with observation of the particular sample by the various desired imaging modes and 2. do not compromise structure viewed at the higher levels of resolution provided by electron and force based imaging technologies. This approach is particularly valuable where simultaneous multiple labeling is required since color differences permit discrimination of differing fluorescent and/or chromatic stains.

scholarly journals Can the Optical Fluctuations of 3C 273 be Random?

1972 ◽  
Vol 44 ◽  
pp. 179-187
Author(s):  
James Terrell ◽  
Kenneth H. Olsen
Keyword(s):  
Power Spectrum ◽  
Spectrum Analysis ◽  
Periodic Variation ◽  
Power Spectrum Analysis ◽  
Effective Length ◽  
New Methods ◽  
The Individual ◽  
Random Fluctuations ◽  
Optical Brightness ◽  
Computer Generation

The fluctuations in optical brightness of the quasi-stellar object 3C 273 have been investigated to determine whether the suggested periodicity of ∼ 10 yr is supported by the observational data extending over 80 yr. New methods of obtaining information from the power spectrum have been used, and moments and trends have also been investigated. No statistically-supportable evidence has been found in the power spectrum for such a non-random variation. The moments and trends are consistent with random fluctuations. If the observed fluctuations are of shot-noise character, due to random outbursts of light, the individual pulses must occur at the rate of 15 ± 5 per year and have an average effective length of 3.2 ± 1 yr. These conclusions were verified by computer-generation and power-spectrum analysis of such random signals. Thus any periodic variation in the brightness of 3C 273, if present, is completely obscured by random fluctuations. The power spectrum, moments, and trend are all consistent with random but long-lasting outbursts of light.

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