scholarly journals ELECTROPHYSIOLOGICAL EVIDENCE FOR LOW-RESISTANCE INTERCELLULAR JUNCTIONS IN THE EARLY CHICK EMBRYO

1968 ◽  
Vol 37 (3) ◽  
pp. 650-659 ◽  
Author(s):  
Judson D. Sheridan
Keyword(s):  
Chick Embryo ◽  
Neural Tube ◽  
Electrical Coupling ◽  
Intercellular Junctions ◽  
Neural Plate ◽  
Early Chick Embryo ◽  
Low Resistance ◽  
Electrophysiological Evidence ◽  
Electron Microscopical ◽  
Different Tissues

Electrophysiological evidence is presented for the exchange of small ions directly between cells interiors, i.e. "electrical coupling," in the early chick embryo. Experiments with intracellular marking show that coupling is widespread, occurring between cells in the same tissue, e.g. ectoderm, notochord, neural plate, mesoderm, and Hensen's node, and between cells in different tissues, e.g. notochord to neural plate, notochord to neural tube, notochord to mesoderm. The coupling demonstrates the presence of specialized low-resistance intercellular junctions as found in other embryos and numerous adult tissues. The results are discussed in relation to recent electron microscopical studies of intercellular junctions in the early chick embryo. The function of the electrical coupling in embryogenesis remains unknown, but some possibilities are considered.

Myogenic specification in somites: induction by axial structures

Development ◽  
1994 ◽  
Vol 120 (6) ◽  
pp. 1443-1452 ◽  
Author(s):  
N. Buffinger ◽  
F.E. Stockdale
Keyword(s):  
Monoclonal Antibodies ◽  
Chick Embryo ◽  
Myosin Heavy Chain ◽  
Neural Tube ◽  
Heavy Chain ◽  
Muscle Fibers ◽  
Fiber Types ◽  
Early Chick Embryo ◽  
Explant Cultures ◽  
Fast Myhc

Specification of the myogenic phenotype in somites was examined in the early chick embryo using organotypic explant cultures stained with monoclonal antibodies to myosin heavy chain. It was found that myogenic specification (formation of muscle fibers in explants of somites or segmental plates cultured alone) does not occur until Hamburger and Hamilton stage 11 (12-14 somites). At this stage, only the somites in the rostral half of the embryo are myogenically specified. By Hamburger and Hamilton stage 12 (15-17 somites), the three most caudal somites were not specified to be myogenic while most or all of the more rostral somites are specified to myogenesis. Somites from older embryos (stage 13–15, 18–26 somites) showed the same pattern of myogenic specification--all but the three most caudal somites were specified. We investigated the effects of the axial structures, the notochord and neural tube, on myogenic specification. Both the notochord and neural tube were able to induce myogenesis in unspecified somites. In contrast, the neural tube, but not the notochord, was able to induce myogenesis in explants of segmental plate, a structure which is not myogenic when cultured alone. When explants of specified somites were stained with antibodies to slow or fast MyHC, it was found that myofiber diversity (fast and fast slow fibers) was established very early in development (as early as Hamburger and Hamilton stage 11). We also found fiber diversity in explants of unspecified somites (the three most caudal somites from stage 11 to 15) when they were recombined with notochord or neural tube. We conclude that myogenic specification in the embryo results in diverse fiber types and is an inductive process which is mediated by factors produced by the neural tube and notochord.

scholarly journals Misexpression of BRE gene in the developing chick neural tube affects neurulation and somitogenesis

2015 ◽  
Vol 26 (5) ◽  
pp. 978-992 ◽  
Author(s):  
Guang Wang ◽  
Yan Li ◽  
Xiao-Yu Wang ◽  
Manli Chuai ◽  
John Yeuk-Hon Chan ◽  
...  
Keyword(s):  
Chick Embryo ◽  
Embryonic Development ◽  
Neural Crest ◽  
Embryo Development ◽  
Neural Tube ◽  
Neural Crest Cells ◽  
Chick Embryos ◽  
Early Chick Embryo

This is the first study of the role of BRE in embryonic development using early chick embryos. BRE is expressed in the developing neural tube, neural crest cells, and somites. BRE thus plays an important role in regulating neurogenesis and indirectly somitogenesis during early chick embryo development.

The Inhibitory Action of Antimycin A in the Early Chick Embryo

Development ◽  
1960 ◽  
Vol 8 (3) ◽  
pp. 314-320
Author(s):  
J. McKenzie ◽  
J. D. Ebert
Keyword(s):  
Chick Embryo ◽  
Enzyme Activities ◽  
Inhibitory Action ◽  
Inhibitory Effect ◽  
Biological Action ◽  
Antimycin A ◽  
Early Chick Embryo ◽  
Sensitive Factor ◽  
Different Tissues

Antimycin A, an antibiotic obtained from an undetermined species of streptomyces, was isolated, crystallized, and described by Dunshee, Leben, Keitt, & Strong (1949), and its biological action has been studied by many workers since then. Ahmad, Schneider, & Strong (1950) demonstrated its effects on the growth and metabolism of yeast, on enzyme activities in the succinoxidase system, and on rats given the drug orally. Potter & Reif (1952) confirmed the inhibitory effect of antimycin A on the succinoxidase system in liver, suggested the presence of an ‘antimycin A-blocked factor’, identical, probably, with the ‘Slater factor’ and showed that, in certain tissues, there is an antimycin A-insensitive pathway for DPN oxidation. The same workers, Reif & Potter (1954), used the drug to characterize the pathways of DPN oxidation in different tissues. Green, Mii, & Kahout (1955) and Thorn (1956) argue from their experiments that the BAL-sensitive (Slater) factor and the antimycin A-sensitive factor are not identical.

scholarly journals ELECTRICAL COUPLING BETWEEN FAT CELLS IN NEWT FAT BODY AND MOUSE BROWN FAT

1971 ◽  
Vol 50 (3) ◽  
pp. 795-803 ◽  
Author(s):  
Judson D. Sheridan
Keyword(s):  
Fat Body ◽  
Electrical Coupling ◽  
Intercellular Junctions ◽  
Brown Fat ◽  
Fat Cells ◽  
Newborn Mice ◽  
Low Resistance ◽  
Direct Observations ◽  
White Fat

White fat from the newt, Triturus pyrrhogaster, fat body, and brown fat from the interscapular fat pad of newborn mice have been tested for the presence of low-resistance intercellular junctions. 42 pairs of amphibian fat cells and 15 pairs of mammalian brown fat cells were found to be "electrically coupled." In most of these cases intracellular deposition of a dye, Niagara Sky Blue: 6B, was used to supplement and confirm direct observations of impalements. Coupling was often difficult to find in both preparations, but the mechanical disturbance of the tissue during the preparative procedures may have uncoupled many cells. The fact that, in both types of fat, coupling was observed between cells separated by one or more other cells suggests that coupling may be more widespread in vivo. Electron microscopy (provided by Dr. J. -P. Revel and Mrs. K. Wolken) of the brown fat revealed frequent intercellular junctions resembling "gap junctions" but possibly lacking the substructure usually visible with colloidal lanthanum infiltration. The results are discussed in relation to current ideas about the exchange of regulatory molecules via low-resistance junctions and about the control of brown fat by hormones and nerves.

Differentiation of the neural plate and neural tube in the young chick embryo

1975 ◽  
Vol 147 (3) ◽  
pp. 309-335 ◽  
Author(s):  
Mary Bancroft ◽  
Ruth Bellairs
Keyword(s):  
Chick Embryo ◽  
Neural Tube ◽  
Neural Plate ◽  
Young Chick

Fates and migratory routes of primitive streak cells in the chick embryo

Development ◽  
1996 ◽  
Vol 122 (5) ◽  
pp. 1523-1534 ◽  
Author(s):  
D. Psychoyos ◽  
C.D. Stern
Keyword(s):  
Chick Embryo ◽  
Primitive Streak ◽  
Final Position ◽  
Fate Map ◽  
Early Chick Embryo ◽  
Carbocyanine Dyes ◽  
Early Stages ◽  
Migratory Routes ◽  
Pass Through ◽  
Different Tissues

We have used carbocyanine dyes to fate map the primitive streak in the early chick embryo, from stages 3+ (mid-primitive streak) to 9 (8 somites). We show that presumptive notochord, foregut and medial somite do not originate solely from Hensen's node, but also from the anterior primitive streak. At early stages (4- and 4), there is no correlation between specific anteroposterior levels of the primitive streak and the final position of their descendants in the notochord. We describe in detail the contribution of specific levels of the primitive streak to the medial and lateral halves of the somites. To understand how the descendants of labelled cells reach their destinations in different tissues, we have followed the movement of labelled cells during their emigration from the primitive streak in living embryos, and find that cells destined to different structures follow defined pathways of movement, even if they arise from similar positions in the streak. Somite and notochord precursors migrate anteriorly within the streak and pass through different portions of the node; this provides an explanation for the segregation of notochord and somite territories in the node.

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