Embryonic tissues are viscoelastic materials

2000 ◽  
Vol 78 (3) ◽  
pp. 243-251 ◽  
Author(s):  
D A Beysens ◽  
G Forgacs ◽  
J A Glazier
Keyword(s):  
Surface Tension ◽  
Metastatic Potential ◽  
Relevant Information ◽  
Specific Cell ◽  
Biologically Relevant ◽  
Embryonic Tissues ◽  
Differential Adhesion ◽  
Equilibrium Configurations ◽  
Experimental Findings ◽  
Differential Adhesion Hypothesis

Early embryonic development is characterized by spectacular morphogenetic processes such as sorting or spreading of tissues. Analogy between viscoelastic fluids and certain properties of embryonic tissues turned out to be useful in interpreting some aspects of these morphogenetic phenomena. In accordance with the differential adhesion hypothesis, the values of tissue-specific surface tensions have been shown to be consistent with the equilibrium configurations such tissues reach in the course of sorting and spreading. A method to measure tissue surface tension and viscoelastic properties is described. Notions like the Laplace's equation relating surface tension to radii of curvature, or the Kelvin model of viscoelasticity are used to analyze the results of these measurements. The fluid analogy is extended to time-dependent phenomena, in particular, to the analysis of cellular pattern evolution in the course of spreading. On the basis of recent experimental findings, we demonstrate that the kinetics of spreading and nucleation in binary fluids can be analyzed using the same formalism. We illustrate how our results can be used to obtain biologically relevant information on the strength of binding between specific cell adhesion molecules under near physiological conditions. We also suggest a diagnostic application of our method to monitor the metastatic potential of tumors. PACS No.: 03.65Ge

Surface tensions of embryonic tissues predict their mutual envelopment behavior

Development ◽  
1996 ◽  
Vol 122 (5) ◽  
pp. 1611-1620 ◽  
Author(s):  
R.A. Foty ◽  
C.M. Pfleger ◽  
G. Forgacs ◽  
M.S. Steinberg
Keyword(s):  
Surface Tension ◽  
Lower Surface ◽  
Limb Bud ◽  
Surface Tensions ◽  
Physical Test ◽  
Embryonic Tissues ◽  
Differential Adhesion ◽  
Embryonic Limb ◽  
The One ◽  
Differential Adhesion Hypothesis

During embryonic development, certain tissues stream to their destinations by liquidlike spreading movements. According to the ‘differential adhesion hypothesis’, these movements are guided by cell-adhesion-generated tissue surface tensions (sigmas), operating in the same manner as surface tensions do in the mutual spreading behavior of immiscible liquids, among which the liquid of lower surface tension is always the one that spreads over its partner. In order to conduct a direct physical test of the ‘differential adhesion hypothesis’, we have measured the sigmas of aggregates of five chick embryonic tissues, using a parallel plate compression apparatus specifically designed for this purpose, and compared the measured values with these tissues' mutual spreading behaviors. We show that aggregates of each of these tissues behave for a time as elasticoviscous liquids with characteristic surface tension values. Chick embryonic limb bud mesoderm (sigma = 20.1 dyne/cm) is enveloped by pigmented epithelium (sigma = 12.6 dyne/cm) which, in turn, is enveloped by heart (sigma = 8.5 dyne/cm) which, in turn, is enveloped by liver (sigma = 4.6 dyne/cm) which, in turn, is enveloped by neural retina (sigma = 1.6 dyne/cm). Thus, as predicted, the tissues' surface tension values fall in the precise sequence required to account for their mutual envelopment behavior.

Contact Inhibition of Overlapping and Differential Cell Adhesion: A Sufficient Model for the Control of Certain Cell Culture Morphologies

1974 ◽  
Vol 16 (2) ◽  
pp. 401-419
Author(s):  
E. MARTZ ◽  
H. M. PHILLIPS ◽  
M. S. STEINBERG
Keyword(s):  
Cell Culture ◽  
Cell Adhesion ◽  
Cell Cultures ◽  
Contact Inhibition ◽  
Present Communication ◽  
Differential Adhesion ◽  
Equilibrium Configurations ◽  
Differential Cell ◽  
Differential Adhesion Hypothesis ◽  
Cells Cultured

Using intuitive arguments, several investigators have proposed that the relative strengths of adhesion of cell to cell and of cell to substratum could determine whether or not monolayering - and specifically contact inhibition of cell overlapping - will occur. In the present communication, these ‘strengths of adhesion’ are given precise physical definitions, and the adhesive relationships which would promote spontaneous cell monolayering are rigorously derived, using the thermodynamic approach embodied in the differential adhesion hypothesis. This analysis verifies that contact inhibition of overlapping could, in principle, be a result solely of differential adhesion. In addition, it is demonstrated that for homogeneous populations of uniform cells cultured on a solid, uniform substratum, eleven distinct equilibrium configurations (cell population morphologies) could be generated merely by varying the relative values of cell-to-cell and cell-to-substratum adhesiveness. Most of these configurations have been observed previously in actual cell cultures.

scholarly journals NoRCE: non-coding RNA sets cis enrichment tool

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Gulden Olgun ◽  
Afshan Nabi ◽  
Oznur Tastan
Keyword(s):  
Expression Patterns ◽  
Target Prediction ◽  
Enrichment Analysis ◽  
Fruit Fly ◽  
Relevant Information ◽  
R Package ◽  
Data Repository ◽  
Biologically Relevant ◽  
Gene Sets ◽  
Data Files

Abstract Background While some non-coding RNAs (ncRNAs) are assigned critical regulatory roles, most remain functionally uncharacterized. This presents a challenge whenever an interesting set of ncRNAs needs to be analyzed in a functional context. Transcripts located close-by on the genome are often regulated together. This genomic proximity on the sequence can hint at a functional association. Results We present a tool, NoRCE, that performs cis enrichment analysis for a given set of ncRNAs. Enrichment is carried out using the functional annotations of the coding genes located proximal to the input ncRNAs. Other biologically relevant information such as topologically associating domain (TAD) boundaries, co-expression patterns, and miRNA target prediction information can be incorporated to conduct a richer enrichment analysis. To this end, NoRCE includes several relevant datasets as part of its data repository, including cell-line specific TAD boundaries, functional gene sets, and expression data for coding & ncRNAs specific to cancer. Additionally, the users can utilize custom data files in their investigation. Enrichment results can be retrieved in a tabular format or visualized in several different ways. NoRCE is currently available for the following species: human, mouse, rat, zebrafish, fruit fly, worm, and yeast. Conclusions NoRCE is a platform-independent, user-friendly, comprehensive R package that can be used to gain insight into the functional importance of a list of ncRNAs of any type. The tool offers flexibility to conduct the users’ preferred set of analyses by designing their own pipeline of analysis. NoRCE is available in Bioconductor and https://github.com/guldenolgun/NoRCE.

scholarly journals Noise matters: elephants show risk-avoidance behaviour in response to human-generated seismic cues

2021 ◽  
Vol 288 (1953) ◽  
pp. 20210774
Author(s):  
Beth Mortimer ◽  
James A. Walker ◽  
David S. Lolchuragi ◽  
Michael Reinwald ◽  
David Daballen
Keyword(s):  
Seismic Noise ◽  
Information Transfer ◽  
Conservation Management ◽  
Sensory Ecology ◽  
Loxodonta Africana ◽  
Relevant Information ◽  
African Elephants ◽  
Risk Avoidance ◽  
Biologically Relevant ◽  
Seismic Vibrations

African elephants ( Loxodonta africana ) use many sensory modes to gather information about their environment, including the detection of seismic, or ground-based, vibrations. Seismic information is known to include elephant-generated signals, but also potentially encompasses biotic cues that are commonly referred to as ‘noise’. To investigate seismic information transfer in elephants beyond communication, here we tested the hypothesis that wild elephants detect and discriminate between seismic vibrations that differ in their noise types, whether elephant- or human-generated. We played three types of seismic vibrations to elephants: seismic recordings of elephants (elephant-generated), white noise (human-generated) and a combined track (elephant- and human-generated). We found evidence of both detection of seismic noise and discrimination between the two treatments containing human-generated noise. In particular, we found evidence of retreat behaviour, where seismic tracks with human-generated noise caused elephants to move further away from the trial location. We conclude that seismic noise are cues that contain biologically relevant information for elephants that they can associate with risk. This expands our understanding of how elephants use seismic information, with implications for elephant sensory ecology and conservation management.

Exploring Dimensions of the Media Dream

2016 ◽  
pp. 1-39 ◽  
Author(s):  
Rollin McCraty ◽  
Stephen Brock Schafer
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Electromagnetic Coupling ◽  
Relevant Information ◽  
Living Systems ◽  
Biologically Relevant ◽  
Dream Analysis ◽  
Psychological Analysis ◽  
Dramatic Structure ◽  
The Media

The earth's magnetic fields are carriers of biologically relevant information that connects all living systems. The electromagnetic coupling of the human brain, cardiovascular and nervous systems, and geomagnetic frequencies supports the hypothesis that the mediated reality of electromagnetic bandwidths can be correlated with bio-energetic and geomagnetic frequencies. Understood as bio-energetic functions (Thinking, Feeling, Sensing, & Intuiting), the media-sphere becomes measurable according to principles of coherency (measured as heart-rate variability, HRV) and principles of Jungian dream analysis (compensation and dramatic structure). It has been demonstrated that the rhythmic patterns in beat-to-beat heart rate variability reflect emotional functions, permeate every bodily cell, and play a central role in the generation and transmission of system-wide information via the electromagnetic field. So, the “media dream” becomes susceptible to psychological analysis leading to a better understanding of unconscious cognitive archetypal patterns of contextual collectives.

scholarly journals Co-expression networks for plant biology: why and how

2019 ◽  
Vol 51 (10) ◽  
pp. 981-988 ◽  
Author(s):  
Xiaolan Rao ◽  
Richard A Dixon
Keyword(s):  
Gene Expression ◽  
Network Analysis ◽  
Expression Analysis ◽  
Expression Profiling ◽  
Recent Literature ◽  
Genomic Data ◽  
Relevant Information ◽  
Plant Biology ◽  
Biologically Relevant

Abstract Co-expression network analysis is one of the most powerful approaches for interpretation of large transcriptomic datasets. It enables characterization of modules of co-expressed genes that may share biological functional linkages. Such networks provide an initial way to explore functional associations from gene expression profiling and can be applied to various aspects of plant biology. This review presents the applications of co-expression network analysis in plant biology and addresses optimized strategies from the recent literature for performing co-expression analysis on plant biological systems. Additionally, we describe the combined interpretation of co-expression analysis with other genomic data to enhance the generation of biologically relevant information.

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