Both Hensen's node, the organizer center in chick embryo, and exogenous retinoic acid are known to induce limb duplication when grafted or applied to the host chick limb bud. Retinoic acid is known to be present in the node and has been proposed as the putative morphogen for chick limb development. Here, we report that Hensen's node from vitamin A-deficient quail embryo induces limb duplication...

A study of the activity and distribution of glutamic dehydrogenase in various tissues of the developing chick embryo has recently been made (Solomon, 1957). It was found that glutamic dehydrogenase showed marked fluctuations of activity in certain tissues at various stages of development. However, as only relatively low amounts of the enzyme were found in all tissues of the chick embryo and fow...

The chick embryo has played a major role in the advance of our understanding of embryonic development. It has been particularly helpful in relation to amniotes like the mouse, for unlike the mouse in the early embryo the epiblast is beautifully flat, while in the mouse it is all curled up. Here I briefly describe some history and a few of the major achievements that came from the chick embryo.

Introduction: There is considerable evidence that glutamate-mediated excitatory neurotransmission plays an important role in mediating the behavioral actions of acutely administered ethanol. The aim of the present study was to investigate the effect of acute ethanol exposure on NR1 subunit of NMDA (n-methyl-d-aspartate) receptor distribution in the cerebral cortex of chick embryo on the 10th...

Evidence was obtained indicating differences in the survival rate of Western equine encephalomyelitis virus after exposure to ultraviolet radiation and methyl methanesulfonate in commercial and leukosisfree chick embryo cells that differed in repair activity. The levels of spontaneous mutagenesis (on the basis of the yield of small palque variants of the encephalomyelitis virus) did not essenti...

701 T HE CHICK EMBRYO 15 used widely in studying drugs for teratogenic activity. Chemicals, which have been injected at the same period of incubation of the chick eml)ryo, may produce separate and characteristic patterns of developmental abnormalities. The effects of many drugs, such as insulin, azasenine, sulfanilamide, 4-aminopteroyl glutamic acid, 8-azaguanine, physostigmine, thallium, lead,...

Chick embryo cells transformed by either of two strains of Rous sarcoma virus (Bryan high titer or Schmidt-Ruppin) have low levels of alkaline phosphatase activity compared with nontransformed chick embryo cells. Essentially no differences in acid phosphatase activity were observed between these transformed and nontransformed cells. A virus mutant, RSV-BH-Ta, induces temperature-dependent trans...

Developmental biology research has used various avian species as model organisms for studying morphogenesis, with the chick embryo being used by the majority of groups. The focus on the chick embryo led Hamburger and Hamilton to develop their definitive staging series nearly 60 years ago and this series is still the mainstay of all laboratories working with avian embryos. The focus on the chick...

introduction: depending on mode, intensity and length of application, and stage of development, the low-frequency electromagnetic fields (lfes) can induce a wide variety of biological effects in organisms. the chick limb bud is a powerful experimental system for study pattern formation in vertebrate embryo. the aim of this study was to examine the effects of an application lfes (50hz, 50g) on c...