Changes in structure of the trophectoderm of a marsupial in Mid-pregnancy up to the time of implantation

1996 ◽  
Vol 8 (4) ◽  
pp. 797 ◽  
Author(s):  
CT Roberts ◽  
WG Breed
Keyword(s):  
Toluidine Blue ◽  
Functional Activity ◽  
Cell Structure ◽  
Morphological Differentiation ◽  
Trophoblast Differentiation ◽  
Squamous Cells ◽  
Sminthopsis Crassicaudata ◽  
Embryonic Disc ◽  
Columnar Cells ◽  
Yolk Sac Placenta

Pre- and peri-implantation embryos of the dasyurid marsupial Sminthopsis crassicaudata were examined for morphological differentiation of the trophectoderm. The cells of unilaminar blastocysts were all squamous and stained intensely with toluidine blue. In bilaminar blastocysts and embryos at the early embryonic-disc stage, the trophectoderm was similar in appearance to, but stained more lightly than, the underlying endoderm. Trophoblast differentiation did not appear to occur until the mesoderm had begun to migrate between the trophoblast and endoderm beyond the embryonic disc. At this stage, trophoblasts had three distinct morphologies: (1) vacuolated, tall and columnar cells in the trilaminar region; (2) large cuboidal cells in the adjacent bilaminar region; and (3) squamous cells in the abembryonic pole of the bilaminar region. These variations in cell structure correlate with differences in subsequent functional activity in these three regions of the yolk sac placenta.

Studies of the Blood and Tests of Some Australian Ascidians. II. The Test of Pyura stolonifera (Heller)

1955 ◽  
Vol 6 (2) ◽  
pp. 139 ◽  
Author(s):  
R Endean
Keyword(s):  
Connective Tissue ◽  
Blood Vessels ◽  
Variable Thickness ◽  
Toluidine Blue ◽  
Single Layer ◽  
Protective Layer ◽  
Fibrillar Material ◽  
Columnar Cells ◽  
Cellulose Solvents ◽  
Large Vessels

The test of this species is particularly bulky and consists of gelatinous material which encloses the fleshy part of the animal, leaving openings only for the two siphons. It also forms a resilient basal stem which anchors the animal to the substratum. The outer surface of the test is impregnated with sand grains, which form a hard protective layer. Blood-vessels traverse the gelatinous material. Two large vessels enter the test and these branch to form ultimately a ramifying system of small blood-vessels. Effectively there are two blood circulations in the test. The blood-vessels have a lining consisting of a single layer of large columnar cells, the appearance of which is described. The gelatinous test resolves itself under the microscope into a network of fibres of variable thickness, but the larger ones at least are aggregates of smaller fibrils. In some cases the fibres are orientated in definite directions. The amorphous interfibrillar material seems to be mainly aqueous, as the test consists of over 97 per cent. of plasma. Ferrocytes wander about in amoeboid fashion amongst the fibres. These enter the substance of the test by migrating across the walls of the bloodvessels. Histologically there is a marked similarity between the appearance of the test and that of vertebrate connective tissue, as in both cases cells are present in a groundmass enmeshed by fibres which stain with orcein and fuchsin. However, the fibres of the test are composed of a very insoluble polysaccliaride, Which although resembling plant cellulose in certain respects will not dissolve in special cellulose solvents nor stain with cellulose stains. A mucopolysaccharide which stains metachromatically with toluidine blue is associated with the fibrillar material, and possibly serves to cement the fibres together since these became disarranged on treatment with hyaluronidase, which removes the mucopolysaccharide. The importance of the test in the general economy of the animal is discussed.

scholarly journals Placenta-Specific Genes, Their Regulation During Villous Trophoblast Differentiation and Dysregulation in Preterm Preeclampsia

2020 ◽  
Vol 21 (2) ◽  
pp. 628 ◽  
Author(s):  
Andras Szilagyi ◽  
Zsolt Gelencser ◽  
Roberto Romero ◽  
Yi Xu ◽  
Peter Kiraly ◽  
...  
Keyword(s):  
Pregnancy Complications ◽  
Hormonal Regulation ◽  
Morphological Differentiation ◽  
Peptide Hormone ◽  
Immune Defense ◽  
Trophoblast Differentiation ◽  
Hormone Synthesis ◽  
Maternal Immune System ◽  
Villous Trophoblast ◽  
Gene Modules

The human placenta maintains pregnancy and supports the developing fetus by providing nutrition, gas-waste exchange, hormonal regulation, and an immunological barrier from the maternal immune system. The villous syncytiotrophoblast carries most of these functions and provides the interface between the maternal and fetal circulatory systems. The syncytiotrophoblast is generated by the biochemical and morphological differentiation of underlying cytotrophoblast progenitor cells. The dysfunction of the villous trophoblast development is implicated in placenta-mediated pregnancy complications. Herein, we describe gene modules and clusters involved in the dynamic differentiation of villous cytotrophoblasts into the syncytiotrophoblast. During this process, the immune defense functions are first established, followed by structural and metabolic changes, and then by peptide hormone synthesis. We describe key transcription regulatory molecules that regulate gene modules involved in placental functions. Based on transcriptomic evidence, we infer how villous trophoblast differentiation and functions are dysregulated in preterm preeclampsia, a life-threatening placenta-mediated obstetrical syndrome for the mother and fetus. In the conclusion, we uncover the blueprint for villous trophoblast development and its impairment in preterm preeclampsia, which may aid in the future development of non-invasive biomarkers for placental functions and early identification of women at risk for preterm preeclampsia as well as other placenta-mediated pregnancy complications.

scholarly journals Involvement of RelA-Associated Inhibitor in Regulation of Trophoblast Differentiation via Interaction with Transcriptional Factor Specificity Protein-1

Endocrinology ◽  
2007 ◽  
Vol 148 (12) ◽  
pp. 5803-5810 ◽  
Author(s):  
Ryoko Minekawa ◽  
Masahiro Sakata ◽  
Yoko Okamoto ◽  
Masami Hayashi ◽  
Aki Isobe ◽  
...  
Keyword(s):  
Expression Vector ◽  
Glucose Transporter ◽  
Morphological Differentiation ◽  
Nuclear Factor Κb ◽  
Inhibitory Effect ◽  
Trophoblast Differentiation ◽  
Glucose Transporter 1 ◽  
Specificity Protein 1 ◽  
Factor Specificity ◽  
Specificity Protein

Glucose transporter-1 (GLUT1), one of the key functional indicators of placental differentiation, has an important role in placental glucose transport. We previously showed that the protein levels of GLUT1 and nuclear transcription factor specificity protein-1 (Sp1) in rat choriocarcinoma cells (Rcho-1 cells) decreased during the differentiation of these cells to giant cells. We also showed that Sp1 was involved in the regulation of GLUT1 gene expression during this process. RelA-associated inhibitor (RAI) is an inhibitor of nuclear factor-κB that was identified by a yeast two-hybrid screen and is preferably expressed in human placenta and heart. RAI was also found to interact with Sp1 and exert an inhibitory effect against the DNA-binding activity of Sp1. We first show here that RAI mRNA expression increased as gestation proceeded and that RAI was localized mainly in the syncytiotrophoblast throughout pregnancy. The chloramphenicol acetyltransferase activity assay in Rcho-1 cells revealed that cotransfection of RAI expression vector resulted in decreased activity of the rat GLUT1 promoter but not in that of a mutated rat GLUT1 promoter lacking the Sp1 binding site. Furthermore, the protein level of RAI increased during differentiation. In addition, transfection of RAI expression vector promoted the morphological differentiation of Rcho-1 cells, and RAI knockdown using RAI-specific small interfering RNA reveals inhibitory effects on the morphological differentiation, as assessed by photomicroscopy. Taken together, these findings suggest that RAI may be involved in the regulation of trophoblast differentiation via interaction with Sp1.

scholarly journals Critical role for transcription factor AP-2α in human trophoblast differentiation

2004 ◽  
Vol 18 (1) ◽  
pp. 99-107 ◽  
Author(s):  
You-Hong Cheng ◽  
Bruce J. Aronow ◽  
Shaikh Hossain ◽  
Bruce Trapnell ◽  
Sue Kong ◽  
...  
Keyword(s):  
Dna Microarray ◽  
Critical Role ◽  
Morphological Differentiation ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Trophoblast Differentiation ◽  
Human Trophoblast ◽  
Cytotrophoblast Cells ◽  
Microarray Analyses

To examine whether AP-2α is a critical component of the genetic program that directs human trophoblast differentiation, we used DNA microarray analyses to characterize the effects of a dominant-negative form of the AP-2 protein upon in vitro differentiating cytotrophoblast cells. Human cytotrophoblast cells (>95% pure) were cultured for 3 days in the presence of control medium or medium containing an adenovirus that expresses a dominant-negative mutant of AP-2 (Ad2.AP-2D/N) or an adenovirus lacking the AP-2 mutant gene (Ad.WT). DNA microarray analyses using Affymetrix human U95Av2 GeneChips were performed on RNA extracted from the three groups of cells immediately prior to and after 3 days of cell culture. Cells infected with Ad2.AP-2D/N or Ad2.WT underwent morphological differentiation similar to that of uninfected cells, with greater than 90% of the cells in each group fusing to form multinucleated syncytiotrophoblast cells. However, Ad2.AP-2D/N markedly inhibited the induction or repression of many genes that were regulated in the noninfected and Ad2.WT-infected cells during differentiation. Eighteen of the 25 most induced genes and 17 of the 20 most repressed genes during differentiation were AP-2 dependent, with the majority of these related to extracellular organization, cellular communication, and signal transduction. Taken together, these findings strongly suggest that AP-2 plays a critical role for both the induction and repression of genes that comprise postsyncytialization gene expression programs of trophoblast differentiation and maturation. AP-2, however, is not required for the fusion of cytotrophoblast cells to form a syncytium or the expression of syncytin.

122 UNIQUE EXPRESSION PATTERNS OF DIFFERENTIATION, GROWTH, AND CELL STRUCTURE FACTORS IN THE ELONGATING PORCINE CONCEPTUS

2006 ◽  
Vol 18 (2) ◽  
pp. 170 ◽  
Author(s):  
L. A. Blomberg ◽  
J. R. Miles ◽  
K. A. Zuelke
Keyword(s):  
Cell Migration ◽  
Protein Expression ◽  
Cellular Localization ◽  
Expression Profiles ◽  
Cell Structure ◽  
Expression Patterns ◽  
Mrna Levels ◽  
Cytokeratin 18 ◽  
Embryonic Disc ◽  
Porcine Conceptus

Elongation of the trophectoderm and gastrulation of the embryonic disc, observed during gestational Days 11 (D11) through 12 (D12), denote a critical period of porcine conceptus development. Serial analysis of gene expression identified genes involved in cellular differentiation/structure (cytokeratin-8 and -18) and growth/cell migration/mesoderm-epithelial interaction (stratifin and midkine), which could potentially be regulated by steroids such as estrogen. Characterization of these factors is lacking in porcine conceptuses, therefore, the current study investigated mRNA expression of these factors in elongating conceptuses and primordial tissues as well as protein expression and cellular localization to better define their biological significance. Conceptuses examined were of ovoid (D11; 6-10 mm), tubular (D11; 11-50 mm), or filamentous (D12; >100 mm) morphology. Cells of the conceptus were highly proliferative at all stages and the embryonic disc of the ovoid conceptus was already polarized as indicated by the protein expression of Ki67 and brachyury. Real-time PCR was utilized to determine the transcript expression profiles. Differential expression of cytokeratin-18 and midkine were not apparent; however, cytokeratin-8 was clearly down-regulated in filamentous compared to ovoid conceptuses. In contrast, stratifin mRNA levels were greatest in tubular conceptuses of 42-50 mm size. Transcripts for cytokeratin-8 and -18, stratifin, and midkine were detected in both cell types (endoderm and trophoblast) of the trophoectoderm. Western blotting and/or immunohistochemistry were utilized to examine protein expression and cellular localization. The embryonic disc of ovoid conceptuses was almost devoid of cytokeratin-18 protein, however, its distribution was uniform throughout the trophectoderm at all stages of elongation. Stratifin and midkine proteins demonstrated more unique expression patterns within the conceptus. Distinct cell populations of the embryonic disc and the trophoectoderm contained stratifin; cellular localization was predominantly cytoplasmic but occasional nuclear translocation was evident. Furthermore, total protein levels of stratifin were not different among ovoid, tubular, and filamentous conceptuses, but proteolysis of the protein was apparent at the filamentous stage. Midkine protein expression was prominent in the embryonic disc of ovoid conceptuses. In tubular conceptuses, midkine was associated with cells that appeared to be migrating away from embryonic disc as well as some concentrating in the tips of the trophectoderm. Our findings suggested that cytokeratin-8 and -18 are associated primarily with the trophectoderm, as seen in other species. Furthermore, the distribution and localization of stratifin and midkine proteins could reflect attributed functions of these factors, minimal anti-proliferative activity in the rapidly growing conceptuses and cell migration important for gastrulation/trophectoderm elongation, respectively.

ABC drug transporter expression and functional activity in trophoblast-like cell lines and differentiating primary trophoblast

2006 ◽  
Vol 290 (5) ◽  
pp. R1357-R1365 ◽  
Author(s):  
Denis A. Evseenko ◽  
James W. Paxton ◽  
Jeffrey A. Keelan
Keyword(s):  
Multidrug Resistance ◽  
Protein Expression ◽  
Cell Lines ◽  
Abc Transporter ◽  
Functional Activity ◽  
Cell Types ◽  
Trophoblast Differentiation ◽  
Mrna And Protein Expression ◽  
Transporter Expression ◽  
Jar Cells

ATP-binding cassette (ABC) efflux transporters are expressed in the human placenta where they are thought to help protect the fetus from xenobiotics. To evaluate models for analysis of ABC transporter function and regulation in the placenta, we have characterized the expression and activity of multidrug resistance (MDR) 1/P glycoprotein (Pgp), MDR3/Pgp, breast cancer resistance protein (BCRP), and multidrug resistance proteins 1 and 2 (MRPs 1, 2) in differentiating primary trophoblast cells and BeWo and Jar cell lines. Real-time PCR and immunoblotting were used for analysis of mRNA and protein expression, respectively. Functional activity was measured using selective inhibitors of efflux of fluorescent substrates, calcein-AM (Pgp and MRPs) and Hoechst 33342 (BCRP). The levels of MDR1 mRNA and protein expression were much higher in trophoblast than in Jar and especially BeWo cells. Expression of MDR3 protein was also lower in BeWo cells. Levels of MDR3 expression were markedly higher than MDR1 levels in all tested cell types. Levels of both MDR1 and MDR3 expression decreased during trophoblast differentiation/syncytialization. BCRP was highly expressed in all cell types and increased with trophoblast differentiation. MRP1 expression was much lower in trophoblasts compared with both cell lines. In contrast to its abundant mRNA expression, MRP2 protein was practically undetectable in BeWo and Jar cells and was present only at very low levels in trophoblast. Functional studies confirmed the presence of active Pgp and BCRP in all studied cell types, whereas MRP functional activity was detected only in BeWo and Jar cells. Both cell lines may be useful models for studying various aspects of placental ABC transporter expression and function, but also have significant limitations. With respect to their ABC protein expression profile, Jar cells are more similar to nondifferentiated cytotrophoblast, whereas BeWo appear to more closely reflect differentiated syncytiotrophoblast.

Three-dimensional anatomy of the 8-day mouse conceptus: a study by scanning electron microscopy

Development ◽  
1976 ◽  
Vol 36 (3) ◽  
pp. 575-596
Author(s):  
A. Tamarin ◽  
A. Boyde
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Three Dimensional ◽  
Vertical Plane ◽  
Single Layer ◽  
Squamous Cells ◽  
Stage Of Development ◽  
Relationship Of ◽  
Columnar Cells ◽  
Scanning Electron

The three-dimensional anatomy of the 8-day mouse conceptus was studied by scanning electron microscopy aided by microdissection within the microscope specimen chamber. Attention was given to the relationship of the extra-embryonic membranes and their subtended compartments and particular emphasis was placed on the ‘inverted’ condition of the embryo at this stage of development. The main points brought forth in this study are: (1) the five basic brain segments are discernible on the basis of surface contours; (2) the cervical fold, extending from the ventrum of the metencephalon to the somatopleure, forms a partition which separates the branchial region from the rest of the amniotic space; (3) the procephalic membrane bifurcates in a vertical plane to form the splanchnopleure and somatopleure lateral to the forebrain, and it bifurcates horizontally to form the dorsal and ventral coverings of the pericardial coelom; (4) the antrum of the pericardial—peritoneal canal opens into the lateral coelom posterior to the cervical fold; (5) the midgut of the embryo is delineated laterally by longitudinal grooves connecting the foregut and hindgut antra; (6) embryonic ectoderm in the neural-fold region is formed by a single layer of pseudostratified columnar cells; (7) the allantois is hollow near its base and the inner surface is formed by a discontinuous layer of squamous cells; (8) blood islands in the extra-embryonic mesoderm form a ring of bulges around the middle of the exocoel. Other structures such as the ectoplacental cavity, the ectoplacental cone and the parietal capsule are also described.

Observations on the nutrition of digenetic trematodes

Parasitology ◽  
1967 ◽  
Vol 57 (4) ◽  
pp. 639-660 ◽  
Author(s):  
D. W. Halton
Keyword(s):  
Exact Sequence ◽  
Cell Structure ◽  
Circulatory System ◽  
Blood Feeding ◽  
Feeding Habit ◽  
Mechanical Process ◽  
Digenetic Trematodes ◽  
Columnar Cells ◽  
Attachment Process ◽  
Host Tissues

Both histological and histochemical studies have been made of the food, mode of feeding, gut cell structure and digestive sequences in a selected number of digenetic trematodes.The species investigated range from gut-dwelling trematodes feeding on the superficial epithelial tissues and associated mucoid secretions of the host to those forms living within the respiratory and circulatory system and feeding exclusively on blood.The mode of feeding is suctorial, brought about by the muscular pharynx and normal attachment process of the oral sucker. In one case there is evidence that this purely mechanical process is supplemented with enzymic secretions produced by the trematode which have a histolytic effect upon host tissues.On the basis of gut cell structure the species investigated are divided into those with cells and associated microvilli that vary in size and appearance so that the gastrodermal border is irregular in outline, and those with a gastrodermis comprising regular cuboidal or columnar cells bearing microvilli organized into a striated border. There is evidence to suggest that this difference in gut cell structure reflects differences in digestion. In all cases, gland cells are absent from the gastrodermis which is capable of both secretory and absorptive functions.Digestion is predominantly an extracellular process, but the exact sequence varies according to the nature of the food ingested and different degrees of adaptation are shown by the trematodes to the blood-feeding habit. The tissue-feeding species show less modification.I wish to thank Dr J. B. Jennings for helpful discussion and advice throughout the course of this work. The study was undertaken during the tenure of a Studentship from the Department of Scientific and Industrial Research.

Representing utility and deploying the body

2020 ◽  
Vol 43 ◽  
Author(s):  
David Spurrett
Keyword(s):  
Functional Activity ◽  
Degrees Of Freedom ◽  
The Body ◽  
Target Article ◽  
Processing Demands ◽  
The Many

Abstract Comprehensive accounts of resource-rational attempts to maximise utility shouldn't ignore the demands of constructing utility representations. This can be onerous when, as in humans, there are many rewarding modalities. Another thing best not ignored is the processing demands of making functional activity out of the many degrees of freedom of a body. The target article is almost silent on both.

A Simple Dichromatic Stain for Plastic Embedded Tissues

1970 ◽  
Vol 28 ◽  
pp. 296-297 ◽  
Author(s):  
G. R. Mackay ◽  
M. L. Mead
Keyword(s):  
Electron Microscopy ◽  
Toluidine Blue ◽  
Biological Material ◽  
Good Reproducibility ◽  
Routine Work ◽  
Staining Techniques

Color contrasting of 1 to 2 micron sections of plastic embedded biological material is an important adjunct to electron microscopy. The procedures in general use today are simple and rapid giving monochromatic results, e.g., toluidine blue. Although many di- and polychromatic histologic staining techniques have been modified to obtain a counterstaining effect with plasticembedded tissue, the methods are usually undesirable for routine work because they are time consuming, complicated and often defy good reproducibility.

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