scholarly journals Avian marginal zone cells function as primitive streak inducers only after their migration into the hypoblast

Development ◽  
1994 ◽  
Vol 120 (9) ◽  
pp. 2501-2509 ◽  
Author(s):  
H. Eyal-Giladi ◽  
T. Lotan ◽  
T. Levin ◽  
O. Avner ◽  
J. Hochman
Keyword(s):  
Incubation Medium ◽  
Marginal Zone ◽  
Electrophoretic Pattern ◽  
Primitive Streak ◽  
Electrophoretic Analysis ◽  
Avian Embryo ◽  
Central Disc ◽  
Induction Process ◽  
Marginal Zones

Hypoblast cells of posterior marginal zone origin have been shown previously to be the inducers of primitive streak in the avian embryo. Here we checked: (1) whether the above cells acquire their inductivity while still whithin the marginal zone; (2) can inductivity be found in supernatants of defined blastodermic regions; (3) can differences in the electrophoretic pattern be shown between inducing and non-inducing tissue fragments and their conditioned media, which might give a clue as to what the inductive substance is. The following observations were made: 1. (a) Stage X chick posterior marginal zone cells prior to their migration into the hypoblast do not induce a primitive streak, when applied to a stage XIII competent epiblast central disc. (b) A posterior marginal zone fragment, when applied to an epiblast central disc, even after being preincubated for up to 9 hours in vitro, is still non-inductive. (c) Mechanically fragmented stage X posterior marginal zones when applied as a layer to epiblast central discs are non-inductive. (d) Hypoblastic tissue in strip form induces a primitive streak. 2. Competent stage XIII epiblast central discs (chick) were incubated for 2 hours in supernatants of stage XIII epiblasts or hypoblasts. Whereas no inductive effect was exerted by the epiblast supernatant, primitive streaks developed in about 50% of the epiblast central discs incubated in the hypoblast supernatant. 3. Electrophoretic analysis (quails) reveals a protein of 28x10-3 Mr that is enriched in both hypoblastic tissue and its incubation medium and not in the epiblast + marginal zone + area opaca and their incubation medium. These findings suggest a possible correlation between this protein and the induction process.

Misexpression of chick Vg1 in the marginal zone induces primitive streak formation

Development ◽  
1997 ◽  
Vol 124 (24) ◽  
pp. 5127-5138 ◽  
Author(s):  
S.B. Shah ◽  
I. Skromne ◽  
C.R. Hume ◽  
D.S. Kessler ◽  
K.J. Lee ◽  
...  
Keyword(s):  
Marginal Zone ◽  
Ectopic Expression ◽  
Primitive Streak ◽  
Axis Formation ◽  
Mesoderm Induction ◽  
Cell Fates ◽  
Signalling Molecules ◽  
Posterior Area ◽  
Area Pellucida

In the chick embryo, the primitive streak is the first axial structure to develop. The initiation of primitive streak formation in the posterior area pellucida is influenced by the adjacent posterior marginal zone (PMZ). We show here that chick Vg1 (cVg1), a member of the TGFbeta family of signalling molecules whose homolog in Xenopus is implicated in mesoderm induction, is expressed in the PMZ of prestreak embryos. Ectopic expression of cVg1 protein in the marginal zone chick blastoderms directs the formation of a secondary primitive streak, which subsequently develops into an ectopic embryo. We have used cell marking techniques to show that cells that contribute to the ectopic primitive streak change fate, acquiring two distinct properties of primitive streak cells, defined by gene expression and cell movements. Furthermore, naive epiblast explants exposed to cVg1 protein in vitro acquire axial mesodermal properties. Together, these results show that cVg1 can mediate ectopic axis formation in the chick by inducing new cell fates and they permit the analysis of distinct events that occur during primitive streak formation.

Induction of primitive streak and Hensen's node by the posterior marginal zone in the early chick embryo

Development ◽  
1998 ◽  
Vol 125 (17) ◽  
pp. 3521-3534 ◽  
Author(s):  
R.F. Bachvarova ◽  
I. Skromne ◽  
C.D. Stern
Keyword(s):  
Chick Embryo ◽  
Marginal Zone ◽  
Lower Layer ◽  
Primitive Streak ◽  
Normal Embryo ◽  
Anterior Pole ◽  
Posterior Edge ◽  
Amphibian Embryo ◽  
Midline Cells ◽  
Marginal Zones

In the preprimitive streak chick embryo, the search for a region capable of inducing the organizer, equivalent to the Nieuwkoop Center of the amphibian embryo, has focused on Koller's sickle, the hypoblast and the posterior marginal zone. However, no clear evidence for induction of an organizer without contribution from the inducing tissue has been provided for any of these structures. We have used DiI/DiO labeling to establish the fate of midline cells in and around Koller's sickle in the normal embryo. In the epiblast, the boundary between cells that contribute to the streak and those that do not lies at the posterior edge of Koller's sickle, except at stage X when it lies slightly more posteriorly in the epiblast. Hypoblast and endoblast (a second lower layer formed under the streak) have distinct origins in the lower layer, and goosecoid expression distinguishes between them. We then used anterior halves of chick prestreak embryos as recipients for grafts of quail posterior marginal zone; quail cells can be identified subsequently with a quail-specific antibody. Anterior halves alone usually formed a streak, most often from the posterior edge. Quail posterior marginal zones without Koller's sickle were grafted to the anterior side of anterior halves. These grafts were able to increase significantly the frequency of streaks arising from the anterior pole of stage X-XI anterior halves without contributing to the streak or node. Stage XII anterior halves no longer responded. A goosecoid-expressing hypoblast did not form under the induced streak, indicating that it is not required for streak formation. We conclude that the marginal zone posterior to Koller's sickle can induce a streak and node, without contributing cells to the induced streak.

Effects of hydroxyl radicals on ATPase and protein structure of myofibrils from rat heart

1991 ◽  
Vol 261 (6) ◽  
pp. H1785-H1790 ◽  
Author(s):  
V. Robert ◽  
S. Ayoub ◽  
G. Berson
Keyword(s):  
Hydroxyl Radicals ◽  
Rat Heart ◽  
Redox State ◽  
Electrophoretic Pattern ◽  
Electrophoretic Analysis ◽  
Myofibrillar Proteins ◽  
Thiol Groups ◽  
Postischemic Reperfusion

Free oxygenated radicals frequently are involved in cardiac arrhythmias and contractility disorders during postischemic reperfusion. The aim of this study was to determine the effects of hydroxyl radicals (.OH) in vitro on myofibrillar Ca-adenosinetriphosphatase (ATPase), on the redox state of thiol groups and the electrophoretic pattern of myofibrillar proteins from rat heart. Myofibrils were treated up to 60 min by .OH generated with 0.3 mM H2O2 and 0.1 mM Fe2+. After a 60-min treatment with .OH, the measurement of thiol groups failed to show any oxidation. On the contrary, ATPase activity and electrophoretic pattern were affected dramatically by treatment with .OH. For all Ca2+ concentrations, ATPase was increased after treatment with .OH, but ATPase activation when Ca2+ rose from pCa 8 to pCa 4.5 was only 92% after 30 min of incubation rather than 226% for untreated myofibrils. The electrophoretic analysis of myofibrillar proteins showed a decrease in myosin heavy chain and formation of aggregates in treated myofibrils. All of these effects were reduced when incubation was performed in the presence of mannitol, a specific scavenger of .OH. No effect was observed with 0.1 mM Fe2+ alone or with 0.3 mM H2O2. The action of .OH was very fast to the extent that the effects were observed after only 15 s of incubation. The results reported in the present study may be related to the impaired relaxation and contracture described in vivo within the first minutes of a postischemic reperfusion and before any change in calcium homeostasis.

Low proliferative and high migratory activity in the area of Brachyury expressing mesoderm progenitor cells in the gastrulating rabbit embryo

Development ◽  
2002 ◽  
Vol 129 (10) ◽  
pp. 2355-2365 ◽  
Author(s):  
Christoph Viebahn ◽  
Christof Stortz ◽  
Sally A. Mitchell ◽  
Martin Blum
Keyword(s):  
Anterior Part ◽  
In Situ Hybridisation ◽  
Primitive Streak ◽  
Cellular Migration ◽  
Avian Embryo ◽  
Migratory Activity ◽  
Interspecific Differences ◽  
Embryonic Disc ◽  
Rabbit Embryo

General mechanisms initiating the gastrulation process in early animal development are still elusive, not least because embryonic morphology differs widely among species. The rabbit embryo is revived here as a model to study vertebrate gastrulation, because its relatively simple morphology at the appropriate stages makes interspecific differences and similarities particularly obvious between mammals and birds. Three approaches that centre on mesoderm specification as a key event at the start of gastrulation were chosen. (1) A cDNA fragment encoding 212 amino acids of the rabbit Brachyury gene was cloned by RT-PCR and used as a molecular marker for mesoderm progenitors. Whole-mount in situ hybridisation revealed single Brachyury-expressing cells in the epiblast at 6.2 days post conception, i.e. several hours before the first ingressing mesoderm cells can be detected histologically. With the anterior marginal crescent as a landmark, these mesoderm progenitors are shown to lie in a posterior quadrant of the embryonic disc, which we call the posterior gastrula extension (PGE), for reasons established during the following functional analysis. (2) Vital dye (DiI) labelling in vitro suggests that epiblast cells arrive in the PGE from anterior parts of the embryonic disc and then move within this area in a complex pattern of posterior, centripetal and anterior directions to form the primitive streak. (3) BrdU labelling shows that proliferation is reduced in the PGE, while the remaining anterior part of the embryonic disc contains several areas of increased proliferation. These results reveal similarities with the chick with respect to Brachyury expression and cellular migration. They differ, however, in that local differences in proliferation are not seen in the pre-streak avian embryo. Rather, rabbit epiblast cells start mesoderm differentiation in a way similar to Drosophila, where a transient downregulation of proliferation initiates mesoderm differentiation and, hence, gastrulation.

ALDOSTERONE STIMULATION IN VITRO

1965 ◽  
Vol 50 (2) ◽  
pp. 301-309 ◽  
Author(s):  
Jürg Müller
Keyword(s):  
Ammonium Chloride ◽  
Human Urine ◽  
Incubation Medium ◽  
The Other ◽  
Ammonium Ions ◽  
Response Curves ◽  
Urine Extract ◽  
Similar Dose ◽  
Aldosterone Production

ABSTRACT An extract of human urine, which was previously shown to stimulate aldosterone production by rat adrenal sections, was further purified. Evidence was obtained that its aldosterone-stimulating effect was due to the presence of ammonium ions. Addition of ammonium chloride and of urine extract to the incubation medium caused identical increases in aldosterone production in vitro. In addition to ammonium ions, rubidium and caesium ions also stimulated aldosterone production up to 250% that of control values without a significant effect on corticosterone production. Similar dose-response curves were obtained when increasing concentrations of potassium, ammonium, rubidium and caesium ions were tested. Aldosterone production was maximal at concentrations of 7 mval/1 and was significantly lower at higher concentrations. When ammonium chloride and ACTH were simultaneously added to the incubation medium, the production of aldosterone and of corticosterone was lower than with ACTH alone. On the other hand, the stimulating activity on aldosterone and corticosterone production by »TPN« (NADP) and glucose-6-phosphate was enhanced by the simultaneous addition of ammonium chloride.

IN VITRO UPTAKE OF TRITIATED OESTRADIOL BY THE ANTERIOR HYPOTHALAMUS AND HYPOPHYSIS OF THE RAT

1970 ◽  
Vol 64 (4) ◽  
pp. 687-695 ◽  
Author(s):  
Junzo Kato
Keyword(s):  
Incubation Medium ◽  
Posterior Hypothalamus ◽  
Anterior Hypothalamus ◽  
Ovariectomized Rats ◽  
Free Medium ◽  
Cortex Cerebri ◽  
Anterior Hypophysis ◽  
In Vitro Uptake

ABSTRACT The anterior, middle, and posterior hypothalamus, the cortex cerebri, the anterior hypophysis as well as the diaphragm of adult ovariectomized rats were incubated in vitro with tritiated 17β-oestradiol. The uptake of tritiated oestradiol was differentially distributed intracerebrally with higher accumulation in the anterior hypothalamus and the hypophysis. Lowering the temperature of the incubation medium caused a reduction in the uptake of radioactivity by the anterior hypothalamus as compared to that found in other brain tissues. Tritiated oestradiol taken up in vitro by the anterior hypothalamus and the hypophysis tended to be retained after further incubation in a steroid-free medium. The addition of non-radioactive 17β-oestradiol to the medium inhibited the uptake of tritiated oestradiol by these tissues. Moreover, pretreatment with non-radioactive 17β-oestradiol in vivo prevented the preferential accumulation of tritiated oestradiol in vitro in the anterior hypothalamus and the hypophysis. These results indicate that oestradiol is preferentially taken up in vitro by the anterior hypothalamus and the hypophysis of the rat.

ÉTUDE DE L'ACTIVITÉ BIOLOGIQUE IN VITRO DES HORMONES GONADOTROPES

1960 ◽  
Vol XXXIII (III) ◽  
pp. 444-450 ◽  
Author(s):  
Maria de la Luz Suarez Soto ◽  
Jean Legault Démare
Keyword(s):  
Paper Chromatography ◽  
Incubation Medium ◽  
Ultraviolet Absorption ◽  
Rat Ovary

ABSTRACT Serum gonadotrophin (PMS) when added to the incubation medium of rat ovary slices increases the amount of Δ4-3-ketosteroids produced. This enhancement is proportional to the logarithm of dose. The ketosteroids were determined by their ultraviolet absorption; paper chromatography has shown that only androst-4-en-3,17-dione is present.

Ligation of tumour-produced mucins to CD22 dramatically impairs splenic marginal zone B-cells

2009 ◽  
Vol 417 (3) ◽  
pp. 673-683 ◽  
Author(s):  
Munetoyo Toda ◽  
Risa Hisano ◽  
Hajime Yurugi ◽  
Kaoru Akita ◽  
Kouji Maruyama ◽  
...  
Keyword(s):  
Sialic Acid ◽  
B Cells ◽  
B Cell ◽  
Marginal Zone ◽  
Cell Signalling ◽  
Negative Regulator ◽  
Mammary Adenocarcinoma ◽  
Marginal Zone B Cells ◽  
Tumour Bearing

CD22 [Siglec-2 (sialic acid-binding, immunoglobulin-like lectin-2)], a negative regulator of B-cell signalling, binds to α2,6- sialic acid-linked glycoconjugates, including a sialyl-Tn antigen that is one of the typical tumour-associated carbohydrate antigens expressed on various mucins. Many epithelial tumours secrete mucins into tissues and/or the bloodstream. Mouse mammary adenocarcinoma cells, TA3-Ha, produce a mucin named epiglycanin, but a subline of them, TA3-St, does not. Epiglycanin binds to CD22 and inhibits B-cell signalling in vitro. The in vivo effect of mucins in the tumour-bearing state was investigated using these cell lines. It should be noted that splenic MZ (marginal zone) B-cells were dramatically reduced in the mice bearing TA3-Ha cells but not in those bearing TA3-St cells, this being consistent with the finding that the thymus-independent response was reduced in these mice. When the mucins were administered to normal mice, a portion of them was detected in the splenic MZ associated with the MZ B-cells. Furthermore, administration of mucins to normal mice clearly reduced the splenic MZ B-cells, similar to tumour-bearing mice. These results indicate that mucins in the bloodstream interacted with CD22, which led to impairment of the splenic MZ B-cells in the tumour-bearing state.

scholarly journals Chromatography-Independent Fractionation and Newly Identified Molecular Features of the Adzuki Bean (Vigna angularis Willd.) β-vignin Protein

2021 ◽  
Vol 22 (6) ◽  
pp. 3018
Author(s):  
Biane Philadelpho ◽  
Victória Souza ◽  
Fabiani Souza ◽  
Johnnie Santos ◽  
Fabiana Batista ◽  
...  
Keyword(s):  
Metal Binding ◽  
Cardiovascular Health ◽  
Binding Capacity ◽  
Biological Activities ◽  
Electrophoretic Analysis ◽  
Adzuki Bean ◽  
Molecular Features ◽  
Health Promoting ◽  
High Degree

Adzuki seed β-vignin, a vicilin-like globulin, has proven to exert various health-promoting biological activities, notably in cardiovascular health. A simple scalable enrichment procedure of this protein for further nutritional and functional studies is crucial. In this study, a simplified chromatography-independent protein fractionation procedure has been optimized and described. The electrophoretic analysis showed a high degree of homogeneity of β-vignin isolate. Furthermore, the molecular features of the purified protein were investigated. The adzuki bean β-vignin was found to have a native size of 146 kDa, and the molecular weight determined was consistent with a trimeric structure. These were identified in two main polypeptide chains (masses of 56–54 kDa) that are glycosylated polypeptides with metal binding capacity, and one minor polypeptide chain with a mass 37 kDa, wherein these features are absent. The in vitro analysis showed a high degree of digestibility of the protein (92%) and potential anti-inflammatory capacity. The results lay the basis not only for further investigation of the health-promoting properties of the adzuki bean β-vignin protein, but also for a possible application as nutraceutical molecule.

scholarly journals Identification in skeletal muscle of a distinct extracellular pool of amino acids, and its role in protein synthesis

1971 ◽  
Vol 121 (5) ◽  
pp. 817-827 ◽  
Author(s):  
R. C. Hider ◽  
E. B. Fern ◽  
D. R. London
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Incubation Medium ◽  
Extensor Digitorum Longus ◽  
Extensor Digitorum ◽  
Longus Muscle ◽  
Kinetics Of

1. The kinetics of radioactive labelling of extra- and intra-cellular amino acid pools and protein of the extensor digitorum longus muscle were studied after incubations with radioactive amino acids in vitro. 2. The results indicated that an extracellular pool could be defined, the contents of which were different from those of the incubation medium. 3. It was concluded that amino acids from the extracellular pool, as defined in this study, were incorporated directly into protein.

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