Symmetry Breaking Instabilities in Biological Systems

Nature ◽  
1969 ◽  
Vol 223 (5209) ◽  
pp. 913-916 ◽  
Author(s):  
I. PRIGOGINE ◽  
R. LEFEVER ◽  
A. GOLDBETER ◽  
M. HERSCHKOWITZ-KAUFMAN
Keyword(s):  
Symmetry Breaking ◽  
Biological Systems

scholarly journals Symmetry breaking and functional incompleteness in biological systems

2020 ◽  
Vol 150 ◽  
pp. 1-12 ◽  
Author(s):  
Andrej Korenić ◽  
Slobodan Perović ◽  
Milan M. Ćirković ◽  
Paul-Antoine Miquel
Keyword(s):  
Symmetry Breaking ◽  
Biological Systems

scholarly journals Pattern-induced local symmetry breaking in active-matter systems

2020 ◽  
Vol 117 (50) ◽  
pp. 31623-31630
Author(s):  
Jonas Denk ◽  
Erwin Frey
Keyword(s):  
Symmetry Breaking ◽  
Biological Systems ◽  
Local Symmetry ◽  
Theoretical Explanation ◽  
Feedback Mechanism ◽  
Hydrodynamic Theory ◽  
Active Matter ◽  
Theoretical Understanding ◽  
Self Organized ◽  
Microscopic Interactions

The emergence of macroscopic order and patterns is a central paradigm in systems of (self-)propelled agents and a key component in the structuring of many biological systems. The relationships between the ordering process and the underlying microscopic interactions have been extensively explored both experimentally and theoretically. While emerging patterns often show one specific symmetry (e.g., nematic lane patterns or polarized traveling flocks), depending on the symmetry of the alignment interactions patterns with different symmetries can apparently coexist. Indeed, recent experiments with an actomysin motility assay suggest that polar and nematic patterns of actin filaments can interact and dynamically transform into each other. However, theoretical understanding of the mechanism responsible remains elusive. Here, we present a kinetic approach complemented by a hydrodynamic theory for agents with mixed alignment symmetries, which captures the experimentally observed phenomenology and provides a theoretical explanation for the coexistence and interaction of patterns with different symmetries. We show that local, pattern-induced symmetry breaking can account for dynamically coexisting patterns with different symmetries. Specifically, in a regime with moderate densities and a weak polar bias in the alignment interaction, nematic bands show a local symmetry-breaking instability within their high-density core region, which induces the formation of polar waves along the bands. These instabilities eventually result in a self-organized system of nematic bands and polar waves that dynamically transform into each other. Our study reveals a mutual feedback mechanism between pattern formation and local symmetry breaking in active matter that has interesting consequences for structure formation in biological systems.

Symmetry breaking in biological systems. From molecules to tissues

2007 ◽  
Vol 18 (6) ◽  
pp. 899-907 ◽  
Author(s):  
Alexandre Michel Robert ◽  
Catherine Sylvie Robert ◽  
Ladislas Robert
Keyword(s):  
Symmetry Breaking ◽  
Biological Systems

scholarly journals Symmetry Breaking as an Interdisciplinary Concept Unifying Cell and Developmental Biology

Cells ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 86
Author(s):  
Andrew B. Goryachev
Keyword(s):  
Developmental Biology ◽  
Symmetry Breaking ◽  
Biological Systems ◽  
Modern Biology ◽  
Definition Of ◽  
Interdisciplinary Concept

The concept of “symmetry breaking” has become a mainstay of modern biology, yet you will not find a definition of this concept specific to biological systems in Wikipedia [...]

Transmission Electron Microscopy of Protein Macromolecules

1971 ◽  
Vol 29 ◽  
pp. 424-425
Author(s):  
Henry S. Slayter
Keyword(s):  
Biological Systems ◽  
Metal Vapor ◽  
Resolving Power ◽  
Electron Microscopic ◽  
Chemical Methods ◽  
Molecular Weights ◽  
The Past ◽  
Physical Chemical ◽  
Transmission Electron

Electron microscopic methods have been applied increasingly during the past fifteen years, to problems in structural molecular biology. Used in conjunction with physical chemical methods and/or Fourier methods of analysis, they constitute powerful tools for determining sizes, shapes and modes of aggregation of biopolymers with molecular weights greater than 50, 000. However, the application of the e.m. to the determination of very fine structure approaching the limit of instrumental resolving power in biological systems has not been productive, due to various difficulties such as the destructive effects of dehydration, damage to the specimen by the electron beam, and lack of adequate and specific contrast. One of the most satisfactory methods for contrasting individual macromolecules involves the deposition of heavy metal vapor upon the specimen. We have investigated this process, and present here what we believe to be the more important considerations for optimizing it. Results of the application of these methods to several biological systems including muscle proteins, fibrinogen, ribosomes and chromatin will be discussed.

Symmetry breaking in convergent-beam diffraction

1989 ◽  
Vol 47 ◽  
pp. 480-481
Author(s):  
D.J. Eaglesham
Keyword(s):  
Symmetry Breaking ◽  
Point Group ◽  
X Ray Diffraction ◽  
Multiple Diffraction ◽  
Space Groups ◽  
Atomic Displacements ◽  
Small Probe ◽  
Phase Sensitive ◽  
Convergent Beam

Convergent Beam Electron Diffraction is now almost routinely used in the determination of the point- and space-groups of crystalline samples. In addition to its small-probe capability, CBED is also postulated to be more sensitive than X-ray diffraction in determining crystal symmetries. Multiple diffraction is phase-sensitive, so that the distinction between centro- and non-centro-symmetric space groups should be trivial in CBED: in addition, the stronger scattering of electrons may give a general increase in sensitivity to small atomic displacements. However, the sensitivity of CBED symmetry to the crystal point group has rarely been quantified, and CBED is also subject to symmetry-breaking due to local strains and inhomogeneities. The purpose of this paper is to classify the various types of symmetry-breaking, present calculations of the sensitivity, and illustrate symmetry-breaking by surface strains.CBED symmetry determinations usually proceed by determining the diffraction group along various zone axes, and hence finding the point group. The diffraction group can be found using either the intensity distribution in the discs

Freeze-fracture cytochemistry: A goal set by Russell Steere in 1957

1993 ◽  
Vol 51 ◽  
pp. 60-61
Author(s):  
Nicholas J Severs
Keyword(s):  
Chemical Nature ◽  
Biological Systems ◽  
Freeze Fracture ◽  
Structural Components ◽  
Major Goal ◽  
Membrane Biology ◽  
Routine Application ◽  
The Future ◽  
Freeze Etching

In his pioneering demonstration of the potential of freeze-etching in biological systems, Russell Steere assessed the future promise and limitations of the technique with remarkable foresight. Item 2 in his list of inherent difficulties as they then stood stated “The chemical nature of the objects seen in the replica cannot be determined”. This defined a major goal for practitioners of freeze-fracture which, for more than a decade, seemed unattainable. It was not until the introduction of the label-fracture-etch technique in the early 1970s that the mould was broken, and not until the following decade that the full scope of modern freeze-fracture cytochemistry took shape. The culmination of these developments in the 1990s now equips the researcher with a set of effective techniques for routine application in cell and membrane biology.Freeze-fracture cytochemical techniques are all designed to provide information on the chemical nature of structural components revealed by freeze-fracture, but differ in how this is achieved, in precisely what type of information is obtained, and in which types of specimen can be studied.

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