Protein Accumulation in Early Chick Embryos Grown under Different Conditions of Explantation

Development ◽  
1959 ◽  
Vol 7 (1) ◽  
pp. 66-72
Author(s):  
L. Gwen Britt ◽  
Heinz Herrmann

The recent development of techniques originally devised by Waddington (1932) for the maintenance of the explanted chick embryo (Spratt, 1947; New, 1955; Wolff & Simon, 1955) has opened the possibility of determining quantitatively some parameters of the developmental processes occurring in embryonic tissues under these conditions. As a result of such measurements, protein accumulation in explanted embryos was found to be much smaller than in embryos developing in the egg. On the other hand, the progress of somite formation was found to take place at similar rates in embryos developing as explants or in situ (Herrmann & Schultz, 1958). The slow rate of protein accumulation in the explanted embryos made it seem desirable to investigate whether under some other conditions of explantation protein accumulation would approach more closely the rate of protein formation observed in the naturally developing embryo.

1994 ◽  
Vol 42 (2) ◽  
pp. 265-272 ◽  
Author(s):  
W H Borman ◽  
D E Yorde

We explored the relationship in chick embryos between somitogenesis and the onset of somite myogenesis by immunodetection of the muscle-specific intermediate filament protein desmin. Early somite desmin expression was detected by whole-mount in situ confocal microscopy. No detectable somite desmin was observed in embryos of 15 somites (Stage 12) or younger. In embryos having between 16 and 26 somites (Stages 12-15), desmin could be detected in somites positioned increasingly more caudal in the embryo. Finally, in embryos of 27 somites (Stage 16) and older, somite desmin expression was consistently present in all but the caudal-most six somites. Although the rate of somite formation is fairly constant, the rate of observed somite desmin expression progressing caudally in the embryo is greater initially than the rate of segmentation. After an embryo has formed about 27 somites, the rate of desmin appearance parallels the rate of segmentation at a distance of about six somites. This result suggests that very early somite myogenesis is not linked to somitogenesis.


Development ◽  
1990 ◽  
Vol 110 (2) ◽  
pp. 609-620 ◽  
Author(s):  
R.W. Pelton ◽  
M.E. Dickinson ◽  
H.L. Moses ◽  
B.L. Hogan

To date, three closely-related TGF beta genes have been found in the mouse; TGF beta 1, TGF beta 2 and TGF beta 3. Previous experiments have indicated that TGF beta 1 and TGF beta 2 may play important roles during mouse embryogenesis. The present study now reports the distribution of transcripts of TGF beta 3 in comparison to the other two genes and reveals overlapping but distinct patterns of RNA expression. TGF beta 3 RNA is expressed in a diverse array of tissues including perichondrium, bone, intervertebral discs, mesenteries, pleura, heart, lung, palate, and amnion, as well as in central nervous system (CNS) structures such as the meninges, choroid plexus and the olfactory bulbs. Furthermore, in several organ systems, TGF beta 3 transcripts are expressed during periods of active morphogenesis suggesting that the protein may be an important factor for the growth and differentiation of many embryonic tissues.


Development ◽  
1983 ◽  
Vol 77 (1) ◽  
pp. 153-165
Author(s):  
L. Fucci ◽  
C. Cirotto ◽  
L. Tomei ◽  
G. Geraci

The synthesis of globins in the chick embryo before the onset of circulation has been studied in situ by specific immunofluorescence labelling of embryonic sections and by labelling newly synthesized proteins in ovo and in vitro in embryonic explants with [3H]leucine. The presence of major primitive haemoglobins is observed by 28 h of incubation. The minor primitive haemoglobins become detectable by immunofluorescence after 40 h of development, shortly before the onset of circulation. 3H-labelling shows that one definitive α chain is synthesized, though in low concentration, from the initial globin detection. The other definitive α chain is observed in embryos of at least 40 h of development. The relative concentration of the two definitive α chains changes rapidly with development indicating a specific mechanism of regulation. An erythropoietic site is observed in the wall of the dorsal aorta in embryos of about 45–50 h of development. From the initial detection, those cells contain all four primitive embryonic haemoglobins, in contrast to what is observed for the cells of the blood islands.


Development ◽  
1981 ◽  
Vol 61 (1) ◽  
pp. 175-190
Author(s):  
K. Palén ◽  
L. Thörneby

Chick embryos were treated in ovo and in vitro with L-phenylalanine from the intermediate streak stage (Hamburger & Hamilton stage 3, 12–13 h of incubation) to the 7-somite stage (H & H stage 9, 29–33 h of incubation). Treatment in ovo resulted in a large number of embryos developing somite blocks, i.e. imperfectly segmented somites. In embryos treated at an early developmental stage (12–21 h of incubation), the blocks of unsegmented somite mesoderm occurred mostly in the somite pairs 1–5, whereas treatment that began at a later stage (24–30 h of incubation) caused blocks in the somite pairs 5–10, i.e. the appearance of blocks of unsegmented somite mesoderm is correlated in time with the onset of the treatment. No difference regarding mitotic indices could be distinguished between normally segmented somites and blocks of unsegmented somite mesoderm. Autoradiography based on tritiated L-phenylalanine showed no regional differences in labelling of the chick embryo body. Electronmicroscopical observations indicate a slightly suppressed formation of microvilli in the cells of the unsegmented mesoderm blocks compared with cells in normally segmented somites. The observed disturbances are probably caused by a suppressed yolk granule decomposition in the developing somite cells. The experiments in vitro support the findings in the in ovo material; at the same time, they reveal an unexpectedly slow diffusion of L-phenylalanine through the vitelline membrane.


1992 ◽  
Vol 70 (7) ◽  
pp. 959-962 ◽  
Author(s):  
I. Oštádalová ◽  
B. Oštádal

The aim of the present study was to establish whether intraamnial administration of toxic doses of isoproterenol to chick embryos increases cardiac accumulation of strontium, the homologue element of calcium. It has been shown that the ability of embryonic tissues (blood, heart, and liver) to accumulate 85Sr decreases significantly during ontogeny. Administration of isoproterenol to chick embryos did not elevate the concentration of 85Sr in the heart. It seems, therefore, that isoproterenol-induced developmental changes in the chick embryonic myocardium are not necessarily due to intracellular calcium (as measured by 85Sr) overload.Key words: heart, isoproterenol, radiostrontium, chick embryo.


Development ◽  
1967 ◽  
Vol 17 (1) ◽  
pp. 239-246
Author(s):  
B. J. Buckingham ◽  
Heinz Herrmann

A structural analogue of nicotinic acid, 3-acetylpyridine, has been shown to produce morphological and physiological abnormalities in a variety of organisms. The effect of 3-acetylpyridine (AP) on chick embryos has been studied by several investigators using the technique of yolk-sac injection (Ackermann & Taylor, 1948; Zwilling & DeBell, 1950; Landauer, 1957; Herrmann, Clark & Landauer, 1963). Following AP treatment at 96 h of incubation, a reduction in body size, underdevelopment of leg musculature and edema were noted. Teratogenic effects of AP when administered after 24 h of incubation were much more diffuse and included instances of cerebral hernia and muscular hypoplasia (Landauer, 1957). Simultaneous injection of nicotinamide (Ackermann & Taylor, 1948; Landauer, 1957) decreased the incidence and severity of these conditions. Landauer (1957) noted the similarity of abnormalities found in AP-treated chick embryos to those of the crooked-neck dwarf mutant described by Asmundson (1945).


Development ◽  
1989 ◽  
Vol 105 (1) ◽  
pp. 119-130 ◽  
Author(s):  
D.R. Primmett ◽  
W.E. Norris ◽  
G.J. Carlson ◽  
R.J. Keynes ◽  
C.D. Stern

This study provides evidence that cells destined to segment together into somites have a degree of cell division synchrony. We have measured the duration of the cell division cycle in somite and segmental plate cells of the chick embryo as 9.5 h using [3H]thymidine pulse- and-chase. Treatment of embryos with any of a variety of inhibitors known to affect the cell division cycle causes discrete periodic segmental anomalies: these anomalies appear about 6–7 somites after treatment and, in some cases, a second anomaly is observed 6 to 7 somites after the first. Since somites take 1.5 h to form, the 6- to 7- somite interval corresponds to about 9–10 h, which is the duration of the cell cycle as determined in these experiments. The anomalies are similar to those seen after heat shock of 2-day chick embryos. Heat shock and some of the other treatments induce the expression of heat-shock proteins (hsp); however, since neither the expression nor the distribution of these proteins relate to the presence or distribution of anomalies seen, we conclude that hsps are not responsible for the pattern of segmental anomalies observed. The production of periodic segmental anomalies appears to be linked to the cell cycle. A simple model is proposed, in which we suggest that the cell division cycle is involved directly in gating cells that will segment together.


Development ◽  
1991 ◽  
Vol 113 (1) ◽  
pp. 239-244 ◽  
Author(s):  
C.D. Stern ◽  
K.F. Jaques ◽  
T.M. Lim ◽  
S.E. Fraser ◽  
R.J. Keynes

We have investigated whether the developing spinal cord is intrinsically segmented in its rostrocaudal (anteroposterior) axis by mapping the spread of clones derived from single labelled cells within the neural tube of the chick embryo. A single cell in the ventrolateral neural tube of the trunk was marked in situ with the fluorescent tracer lysinated rhodamine dextran (LRD) and its descendants located after two days of further incubation. We find that clones derived from cells labelled before overt segmentation of the adjacent mesoderm do not respect any boundaries within the neural tube. Those derived from cells marked after mesodermal segmentation, however, never cross an invisible boundary aligned with the middle of each somite, and tend to be elongated along the mediolateral axis of the neural tube. When the somite pattern is surgically disturbed, neighbouring clones derived from neuroectodermal cells labelled after somite formation behave like clones derived from younger cells: they no longer respect any boundaries, and are not elongated mediolaterally. These results indicate that periodic lineage restrictions do exist in the developing spinal cord of the chick embryo, but their maintenance requires the presence of the adjacent somite mesoderm.


Author(s):  
J. I. Bennetch

In a recent study of the superplastic forming (SPF) behavior of certain Al-Li-X alloys, the relative misorientation between adjacent (sub)grains proved to be an important parameter. It is well established that the most accurate way to determine misorientation across boundaries is by Kikuchi line analysis. However, the SPF study required the characterization of a large number of (sub)grains in each sample to be statistically meaningful, a very time-consuming task even for comparatively rapid Kikuchi analytical techniques.In order to circumvent this problem, an alternate, even more rapid in-situ Kikuchi technique was devised, eliminating the need for the developing of negatives and any subsequent measurements on photographic plates. All that is required is a double tilt low backlash goniometer capable of tilting ± 45° in one axis and ± 30° in the other axis. The procedure is as follows. While viewing the microscope screen, one merely tilts the specimen until a standard recognizable reference Kikuchi pattern is centered, making sure, at the same time, that the focused electron beam remains on the (sub)grain in question.


2000 ◽  
Vol 3 (6) ◽  
pp. 591-596 ◽  
Author(s):  
Virpi V. Smith ◽  
Amanda J. Williams ◽  
Vas Novelli ◽  
Marian Malone

We report two infants with the acquired immunodeficiency syndrome (AIDS) and rectal bleeding due to cytomegalovirus (CMV) ileitis and colitis with minimal focal mucosal ulceration but with extensive leiomyolysis of the muscularis propria. Immunostaining and in situ hybridization for CMV showed numerous viral inclusions in the myocytes of the muscularis propria and vascular endothelium/smooth muscle with only occasional inclusions present in the muscularis mucosae. Colectomy was curative in one patient; in the other the bowel was only examined at postmortem.


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