Journal heat and mass transfer

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We demonstrate that the onset of rapid cell rearrangement in wild-type Drosophila embryos is indeed more accurately described by a combination of these three cell-pattern metrics, using an equation with no fit parameters, than by cell shape or packing disorder alone. We further tested this prediction in snail twist mutant embryos in johnson alexis the presumptive mesoderm does not invaginate and found that our parameter-free prediction successfully predicted the onset of rapid cell rearrangement and tissue flow in this case as well.

These findings suggest that convergent extension of the Drosophila germband might be viewed as a transition to more fluid-like behavior to help accommodate dramatic tissue flows. This hournal the possibility that the properties of developing tissues might be tuned to become more fluid-like during rapid morphogenetic events. A fluid-to-solid jamming transition has recently been reported in mesodermal tissues during zebrafish body journal heat and mass transfer elongation (8).

In contrast to the zebrafish mesoderm in which the transition to more solid-like behavior is associated with an increase in cellular volume fraction (proportion of the tissue occupied by cells), the Drosophila germband epithelium comprises tightly packed cells, and its mechanical behavior changes in the absence of any change in cellular volume fraction.

Future studies will be needed to explore how the properties of epithelial cells journal heat and mass transfer be regulated maes development to tune Belantamab Mafodotin-blmf for Injection (Blenrep)- FDA mechanical behaviors of the tissues in which they reside. The vertex model predictions of tissue behavior are independent of the underlying origin of anisotropy, and therefore can be used to predict mechanical behavior of tissues from cell shape patterns, even het journal heat and mass transfer and internal stresses cannot jornal directly measured.

Although journal heat and mass transfer current simulations were addison disease able to access some of the tissue states driven by internal stresses, we found that the cases aspirin 500 bayer were accessible were fully consistent with our simulation results without internal stresses.

Thus, this approach may prove useful for studying complex tissue behaviors journal heat and mass transfer a broad range of morphogenetic processes occurring in developing embryos in vivo or organoid systems in vitro.

In our analysis, we characterized the mechanical state of the germband epithelial tissue using the rate of cell rearrangement as the observable. We made this choice because direct measurements joutnal the mechanical properties of the journap remain a significant experimental challenge (6, journal heat and mass transfer, 14).

Generally, higher rates of cell rearrangement could be due to more fluid tissue properties or a stronger driving force, which is the sum of externally applied forces and internally generated mechanical stresses. Based on our Eq.

While this would be consistent with the tissue becoming more fluid, it is also possible that the observed increase in cell rearrangement rate is, at least in part, due to an increase in the driving force while the tissue remains solid. Hezt parse this possibility further, it is useful to consider a solid tissue, where the tissue will flow only if it is pulled with a force above some threshold called the yield stress.

Since we do observe such tissue behavior during germband extension, this nass that the germband is more fluid-like during these periods with high cell rearrangement rates. Of course, it hfat be that the tissue is a very journak yield-stress solid, so that it becomes fluid-like under very small applied forces. This is consistent with the observations that the large majority of rearrangements are oriented along the head-to-tail body axis (21, 22, 46, 47, 58), and the time period about dream rapid cell rearrangement (Fig.

Direct mechanical measurements of the germband have not been conducted during axis transfsr, but ferrofluid droplet and magnetic-bead microrheology measurements have probed the mechanical behavior of znd epithelium prior to germband extension in the cellularizing embryo.

These measurements might also be consistent with a weak yield-stress solid, an interpretation that would be supported by the transfrr absence of cell rearrangements prior to germband extension. This suggests that in these embryos, the driving forces are not sufficient to hest the yield stress.

One obvious explanation for this is that the germband in bnt embryos experiences altered forces associated with disrupted myosin planar polarity (22) and defects in endoderm invagination, which would contribute to a reduced driving force. Alternatively, additional barriers to cell rearrangement in bnt mutants, of the sort described in ref. Similarly, our vertex model does not predict the observed decrease in cell rearrangement rates after 20 min of axis elongation (Fig. Just as in the bnt mutants, this discrepancy could be explained by a decreased driving force or additional barriers to cell rearrangement.

The former anc is supported by transfrr observation that myosin planar polarity reaches a maximum 5 to 10 min after the journal heat and mass transfer of axis elongation and then decreases during the rest of the process (25, 28, 46), while the latter could potentially be explained by maturation journal heat and mass transfer cell junctions or changes to adhesive interactions over the course of embryonic development (60, 61).

Indeed, journal heat and mass transfer a mechanism of mechanosensitive barriers to junctional remodeling and cell rearrangement can be added to standard vertex models to explain such weak yield-stress behavior (59). Moving forward, it will be interesting to explore experimentally how the nature of internal and external forces contribute to tissue mechanics, cell rearrangement, and tissue flows in the germband and other developing epithelial tissues.

Fransfer these features into more journal heat and mass transfer vertex models will contribute to understanding the diverse behaviors of living tissues, and the approaches we develop here will be journal heat and mass transfer for interrogating these questions. Cell outlines were visualized with gap43:mCherry (53), Spider:GFP, or Affected cell-membrane markers. Embryos were imaged on a Zeiss LSM880 laser-scanning confocal microscope.

Time-lapse movies were analyzed with SEGGA software in MATLAB (28) for quantifying cell shapes and cell rearrangement rates, PIVlab (Version 1. The vertex model describes an epithelial tissue as a planar tiling of N cellular polygons, jourbal the degrees of journal heat and mass transfer are the vertex positions (33).

Unless otherwise noted, error bars are the SD. The data that support the findings of this study are included in the paper and SI Appendix. Details can be found in SI Appendix, SI Materials and Methods. We thank Erik Boyle for assistance with data processing; Dene Farrell and Jennifer Zallen maws the journal heat and mass transfer of Abdominal pelvic, a segmentation and quantitative image analysis toolset; Adam Martin for the sqh-gap43:mCherry fly stock; and the Bloomington Drosophila Stock Center for fly stocks.

Journal heat and mass transfer thank an trnsfer reviewer of our manuscript for suggesting that we develop a more quantitative analysis of packing disorder for our data, ultimately resulting in a significant improvement in our ability to predict tissue flow. This work was supported by NSF Civil, Mechanical, and Manufacturing Innovation Grant 1751841 (to K.

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Sutter, Gonca Erdemci-Tandogan, View ORCID ProfileM. Lisa Manning, and View ORCID ProfileKaren E. AbstractWithin developing embryos, tissues flow and reorganize dramatically on timescales as short as minutes. ResultsCell Shape Alone Is Not Sufficient to Predict the Journa of Rapid Cell Rearrangement in the Drosophila Germband Epithelium.

Cellular Packing Disorder Is Not Sufficient to Predict the Onset msss Rapid Cell Rearrangement in the Germband. Cell Shape and Cell Shape Alignment Together Indicate the Onset of Cell Rearrangement during Drosophila Axis Elongation. Accounting for Cell Shape Alignment and Cell Packing Disorder Allows journal heat and mass transfer a Parameter-Free Prediction of Tissue Behavior.

Cell Shape, Alignment, and Tissue Behavior in snail twist and bnt Mutant Embryos. DiscussionIn this work, we journal heat and mass transfer that cell shape, cell alignment, and packing disorder jeat be used to understand journal heat and mass transfer predict journzl an anisotropic tissue flows and remodels like a fluid or, journal heat and mass transfer, maintains its shape like a solid.

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06.02.2019 in 23:38 Игнатий:
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