Frog’s eggs

Gene amplification production of extrachromo-somal copies of the genes for ribosomal RNA. In frog s egg cells G.a. leads to the formation of numerous extrachromosomal nucleoli. G.a. is thus a special regulatory mechanism for RNA. It is not the same as Redundancy (see), which is the presence of multiple copies of the same gene on the chromosome. 

Piarda. According to Grelier (153), while all the Piaroa (De aruwa) hunters knew how to make the poison, only a few were considered expert. Several Strychnos species were used, and the soil in which the plants grew and the time of collection (at the end of the dry season) were believed to be important factors in ensuring the quality of the product. The Piaroa emphasized that it was the fibrous inner bark of the stem that had the poison in the most concentrated form they tested a sliver of it on a frog before selecting the material to be used, which was then carefully decorticated on the spot. The extraction was carried out with cold water, and this was followed by filtration and concentration over a moderate fire, which could take 24 hours or more, until it became a thick, syrupy paste. While still hot, it was poured into small calabashes about the size of a duck s egg. The poison—the curare fuerte of the Piaroa—solidified to a brittle resin which had to be moistened before it could be coated on the darts. 

Nucleic acids are substituted polymers of the aldopentose ribose that carry an organism s genetic information. A tiny amount of DNA in a fertilized egg cell determines the physical characteristics of the fully developed animal. The difference between a frog and a human is encoded in a relatively small part of this DNA. Each cell carries a complete set of genetic instructions that determine the type of cell, what its function will be, when it will grow and divide, and how it will synthesize all the structural proteins, enzymes, fats, carbohydrates, and other substances the cell and the organism need to survive. 

Busa, W.B., J.E. Ferguson, S.K. Joseph, J.R. Williamson R. Nuccitelli. 1985. Activation of frog (Xenopus laevis) eggs by inositol trisphosphate. I. Characterization of Ca " release from intracellular stores. J. Cell Biol. 101 677-82. 

Pavelka, L.A., Kim, Y.H., and Mosher, H.S. 1977. Tetrodotoxin and tetrodotoxin/like compounds from the eggs of the Costa Rican frog, Atelopus cUriqidensis. Toxicon 15, 135-139. 

FIGURE 8.21 Premature ventricular contraction following ultrasound irradiation, during diastole, of the in vivo frog heart. The top trace is aortic pressure and below is the EGG. A lithotripter pulse of 20 MPa, 5 msec duration, is delivered at the vertical arrow. (Adapted from Dalecki, D., Raeman, C.H., Child, S.Z., and Carstensen, E.L. 1997. Ultrasound Med. BioL 23 275-285.)... 

Warkentin, K. M., Currie, C. R., and Rehner, S. A., 2001, Egg-killing fimgus induces early hatching of red-eyed tree frog gs. Ecology 82 2860-2869. 

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