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...

The titration curve for the virus of Eastern equine encephalomyelitis inoculated into the 10 day old chick embryo shows that the maximum increase in virus content continues until shortly before the generalized destruction of the embryo is apparent. This is followed by a stationary phase. Histological studies of infected embryos fail to demonstrate selective tissue destruction, and titrations sh...

Areca catechu seeds and their extract/s are currently used to treat various ailments infections including snakebites. The purpose of this investigation was assess the inhibiting/neutralizing effect ethyl acetate aqueous ethanolic seed extracts A. on Bungarus caeruleus (krait) venom. enzyme activities inhibition were evaluated using standard procedures (in vitro). In vivo studies conducted chick...

Asymmetric expression of sonic hedgehog (Shh) in the left side of Hensen's node, a crucial step for specifying the left-right (LR) axis in the chick embryo, is established by the repression of Shh expression in the right side of the node. The transcriptional regulator that mediates this repression has not been identified. We report the isolation and characterization of a novel chick Polycomblik...