Change of the differentiation pattern of amphibian ectoderm after the increase of the initial cell mass

In this paper, we focus on the qualitative analysis of a parabolic–elliptic attraction–repulsion chemotaxis model with logistic source. Applying a fixed point argument, [Formula: see text]-estimate technique and Moser’s iteration, we derive that the model admits a unique global solution provided the initial cell mass satisfying [Formula: see text] for [Formula: see text] While for [Formula: see text], there are no restrictions on the initial cell mass and the result still holds.

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Analyzing growth in cell cultures. II. Effect of initial cell mass on growth

Canadian Journal of Botany ◽

10.1139/b86-034 ◽

1986 ◽

Vol 64 (1) ◽

pp. 238-241 ◽

Cited By ~ 4

Author(s):

Susan R. Singer ◽

Carl N. McDaniel

Keyword(s):

Growth Rate ◽

Cell Line ◽

Cell Lines ◽

Growth Rates ◽

Relative Rate ◽

Cell Mass ◽

Mass Effect ◽

Initial Mass ◽

Lower Growth ◽

Initial Cell

Numerous factors must be considered when analyzing growth in a cultured cell system. One extremely critical factor is the initial cell mass. The effect of initial mass (10 to 400 mg) on growth rate was assessed for cell lines tolerant and susceptible to the herbicides 3-amino-1,2,4-triazole (amitrole) and N-(phosphonomethyl)glycine (glyphosate). For a given cell line, the relationship between initial mass and growth rate was comparable in the presence and absence of the growth inhibitors. However, among cell lines the response varied. For one amitrole- and glyphosate-tolerant cell line, increased initial callus mass resulted in an increased relative rate of growth. However, the opposite effect was observed for another cell line which was also tolerant to both herbicides. For a third cell line which was herbicide sensitive no initial mass effect was observed. A fourth cell line (amitrole tolerant – glyphosate sensitive) also showed no initial mass effect except for the very small 10-mg calluses, which had significantly lower growth rates. The observed effect of initial mass was dependent on the method of calculating growth rates.

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Morphological changes and germ layer formation in the porcine embryos from days 7–13 of development

Zygote ◽

10.1017/s0967199413000531 ◽

2013 ◽

Vol 23 (2) ◽

pp. 266-276 ◽

Cited By ~ 8

Author(s):

Ruizhen Sun ◽

Lei Lei ◽

Shichao Liu ◽

Binghua Xue ◽

Jianyu Wang ◽

...

Keyword(s):

Inner Cell Mass ◽

Morphological Changes ◽

Cell Mass ◽

Primitive Streak ◽

Thin Sections ◽

Asynchronous Development ◽

Embryonic Disc ◽

Gradual Disappearance ◽

Differentiation Pattern ◽

Migrating Cells

SummaryMorphogenesis and identification of embryonic differentiation in porcine embryos are crucial issues for developmental biology and laboratory animal science. The current paper presents a study on the asynchronous development of hatched porcine embryos from days 7 to 13 post-insemination. Examination of semi-thin sections of the hypoblast showed that it had characteristics similar to those of the mouse anterior visceral endoderm during embryonic disc formation. Also, a cavity appeared in the epiblast, which was similar to a mouse proamniotic cavity. With the gradual disappearance of Rauber's layer, the cavity opened and contacted the external environment directly, all of which formed the embryonic disc. To confirm the differentiation characteristics, we performed immunohistochemical analyses and showed that GATA6 was detected clearly in parietal endoderm cells during embryonic disc establishment. OCT4 was expressed in the inner cell mass (ICM) and trophoblast of hatched blastocysts and in the epiblast during formation of the embryonic disc. However, OCT4 showed comparatively decreased expression in the posterior embryonic disc, primitive streak and migrating cells. SOX2 was present in the ICM and epiblast. Therefore, both SOX2 and OCT4 can be used as markers of pluripotent cells in the porcine embryonic disc. At the start of gastrulation, staining revealed VIMENTIN in the posterior of the embryonic disc, primitive streak and in migrating cells that underlay the embryonic disc and was also expressed in epiblast cells located in the anterior primitive streak. Together with serial sections of embryos stained by whole mount immunohistochemistry, the mesoderm differentiation pattern was shown as an ingression movement that took place at the posterior of the embryonic disc and with bilateral migration along the embryonic disc borders.

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Ultrastructural Correlations between Clonal Human Tumor Colonies and in Vivo Neoplasms

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100053711 ◽

1982 ◽

Vol 40 ◽

pp. 210-211

Author(s):

M.J. Murphy ◽

R.R. Price ◽

J.C. Sloman

Keyword(s):

Cultured Cells ◽

Human Tumor ◽

Cell Type ◽

Tumor Mass ◽

Initial Cell ◽

Cloning Assay ◽

Human Tumor Cloning ◽

The Relationship

The in vitro human tumor cloning assay originally described by Salmon and Hamburger has been applied recently to the investigation of differential anti-tumor drug sensitivities over a broad range of human neoplasms. A major problem in the acceptance of this technique has been the question of the relationship between the cultured cells and the original patient tumor, i.e., whether the colonies that develop derive from the neoplasm or from some other cell type within the initial cell population. A study of the ultrastructural morphology of the cultured cells vs. patient tumor has therefore been undertaken to resolve this question. Direct correlation was assured by division of a common tumor mass at surgical resection, one biopsy being fixed for TEM studies, the second being rapidly transported to the laboratory for culture.

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Use of F9 teratocarcinoma STEM cells to study cell-matrix interactions in the early mouse embryo

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100123416 ◽

1992 ◽

Vol 50 (1) ◽

pp. 602-603

Author(s):

Marc Lenburg ◽

Rulang Jiang ◽

Lengya Cheng ◽

Laura Grabel

Keyword(s):

Mouse Embryo ◽

Inner Cell Mass ◽

Cell Mass ◽

Cell Types ◽

Embryoid Bodies ◽

F9 Cells ◽

Cell Matrix ◽

Matrix Interactions ◽

Cell Matrix Interactions ◽

F9 Teratocarcinoma

We are interested in defining the cell-cell and cell-matrix interactions that help direct the differentiation of extraembryonic endoderm in the peri-implantation mouse embryo. At the blastocyst stage the mouse embryo consists of an outer layer of trophectoderm surrounding the fluid-filled blastocoel cavity and an eccentrically located inner cell mass. On the free surface of the inner cell mass, facing the blastocoel cavity, a layer of primitive endoderm forms. Primitive endoderm then generates two distinct cell types; parietal endoderm (PE) which migrates along the inner surface of the trophectoderm and secretes large amounts of basement membrane components as well as tissue-type plasminogen activator (tPA), and visceral endoderm (VE), a columnar epithelial layer characterized by tight junctions, microvilli, and the synthesis and secretion of α-fetoprotein. As these events occur after implantation, we have turned to the F9 teratocarcinoma system as an in vitro model for examining the differentiation of these cell types. When F9 cells are treated in monolayer with retinoic acid plus cyclic-AMP, they differentiate into PE. In contrast, when F9 cells are treated in suspension with retinoic acid, they form embryoid bodies (EBs) which consist of an outer layer of VE and an inner core of undifferentiated stem cells. In addition, we have established that when VE containing embryoid bodies are plated on a fibronectin coated substrate, PE migrates onto the matrix and this interaction is inhibited by RGDS as well as antibodies directed against the β1 integrin subunit. This transition is accompanied by a significant increase in the level of tPA in the PE cells. Thus, the outgrowth system provides a spatially appropriate model for studying the differentiation and migration of PE from a VE precursor.

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