Chick embryo extract

There are a number of media available which are not based on a detailed investigation of growth requirements, but rather include crude mixtures of nutrients added to promote cell growth. These include lactalbumin hydrolysate (Appendix 1 Table 9) or yeast extract (Appendix 4) to provide an inexpensive source of amino acids or vitamins. Thus Melnick s monkey kidney media A and B (Melnick, 1955) contain lactalbumin hydrolysate and calf serum in Hanks and Earle s BSS, respectively. Chick embryo extract and tryptose phosphate broth (Appendix 1, Tables 11 and 12) are also used occasionally and their use is referred to where appropriate throughout the book. Mitsuhashi and Maramorosch mosquito cell medium contains lactalbumin hydrolysate, yeast extract and foetal calf serum in a specially developed saline (Mitsuhashi and Maramorosch, 1964 Singh, 1967). 

Myoblasts may differentiate and fuse without undergoing DNA synthesis (Nadel-Ginard, 1978), but fusion does not occur in calcium-free medium. Thus, if chick embryo myoblasts are set up in calcium-free (< 20/xM Ca2+) DMEM containing 5% heat inactivated FBS and 2% chick embryo extract (Appendix 1) the fusion which normally starts at around 24 h fails to occur. Addition of 1.4 mM CaCl 2 after 50 h will now produce synchronised fusion of cells (Wakelam and Pette, 1982). 

By the use of no-flow cytometry, Barald (1989) has isolated this subpopulation of cells from neural crest cultures and studied its behaviour under a variety of different culture conditions. The cells proliferate in the presence of 15% fetal bovine serum and high concentrations of chick embryo extract, but do not differentiate. However, in chick serum, elevated K+ or heart-, iris- or lung-conditioned medium, the cells stopped proliferating and all of the cells became neuron-like within 10 days (Barald, 1989). These cells also stained positively for choline acetyl transferase (ChAT). 

Another group of experimentors tried to study the preferential utilisation of intact proteins or partial hydrolysates by means of the metabolic trap technique, which consists in measuring the effectiveness with which a labeled free amino acid can compete with larger protein fragments in the formation of new protein. The most positive evidence for the direct utilisation of such fn ments was generally found with embryonic and tumor tissues. Thus Ebert (343) found that when transplants of chick embryo kidney, liver, or spleen, labeled with S -methionine, were made into chick embryos, the radioactivity appeared predominantly in the correspondit organ, and that this transfer of radioactivity could not be inhibited by free methionine. Similarly, Francis and Winnick (344) found that the soluble proteins of a chick embryo extract were utilized in preference to free amino acids by embryonic heart cultures and that, furthermore, p-fluorophenyl-alanine did not inhibit the transfer of phenylalanine from the embryo extract proteins. These experiments, however, are open to many interpretations, especially since functional adoption (or merely adsorption) of the exogenous proteins by the different tissues has not been excluded. 

Enzymic transfer of D-xylose from uridine 5 -(D-xylopyranosyI-HC pyrophosphate) to L-serine residues of endogenous protein acceptors from (a) a cell tumor of the mouse188 and (b) chick-embryo cartilage189 occurs in cell-free extracts of both of these tissues, in the absence of biosynthesis of protein. The enzyme preparations employed were from the supernatant liquor, although activity was also present in the insoluble fractions. In these two types of tissue, the acceptors are heparin and chondroitin sulfate, respectively, but the presence of other D-xylose-containing glycoproteins in ascites fluid from... 

Ex vivo models, such as mouse bladder (Poste et al., 1980) or human amnion (Russo et al., 1986) either denuded of epithelium and/or reseeded with endothelial cells (Foltz et al., 1982) may be considered too simplified systems. According to Kim et al. (1998), these recapitulate poorly the structure of the blood vessels and, in particular, small vessels. .. where most of the cancer cell invasion is believed to take place . These authors describe an interesting alternative where cells are inoculated on the chick chorioallantoic membrane (CAM) of an artificially created air sac in chick embryo. To detect and quantitate tumor cells actively penetrated in the ventral lower CAM , genomic DNA is extracted and used as a template for human Alu sequence identification by PCR. These sequences, unique to human and higher primate DNA, are repetitive... 

Chick embryo erythroblasts at 14 days actively synthesize globin, whereas cultured undifferentiated MSB cells do not. (a) Nuclei from each type of cell were isolated and exposed to increasing concentrations of DNase I. The nuclear DNA was then extracted and treated with the restriction enzyme SamHI, which cleaves the DNA around the globin sequence and normally releases a... 

Cell death of spinal motoneurons in the chick embryo following deafferentation rescue effects of tissue extracts, soluble proteins, and neurotrophic agents. J. Neurosci. 14 1619-1 MO. 

Floissac, M., and S. Chopin. 1999. Ginkgo biloba extract is embryo-toxic to chick embryos. FASEB J. 13 5. 

In chick embryos, a dose of 0.1 mg pomegranate whole fruit hydroalcoholic extract per embryo was nontoxic (Vidal et al. 2003). 

Special morphogenetic factors seem also to exist in other induction systems. In all vertebrate embryos organogenesis of the cartilageneous vertebral column has been found to depend on the inductive activity of the spinal cord and the notochord (Strudel, 1967). Semitic mesenchyme isolated from early chick embryos does not form cartilage in contrast to somites taken from older embryos. In isolated somitic mesenchyme from 2- to 3-day-old embryos the formation of cartilage can be induced by extracts from spinal cord and notochord (Strudel, 1962). The chemical nature of the inducer is not yet known. Metachromatic... 

The DNA is certainly not identical with the cytoplasmic inhibitor which was extracted from the 105,000 g supernatant of chick embryos. The partially purified cytoplasmic inhibitor does not contain any DNA and the inhibitory activity is not destroyed by DNase, whereas the inhibition by DNA is completely abolished after treatment with DNase (Tiede-mann et al., 1972a). 

New still considered heterologous sera unsatisfactory for embryo culture. In a previous study (New and Stein, 1964) in which mouse and rat embryos were cultured on clots of plasma and embryo extract, it was interesting to note that development was eomparable with embryo extraet prepared from 13-day chick embryos or from the entire uterine contents of 17-19-day pregnant mice. 

Our first investigation of the possible participation of ADPRT activity in cell differentiation used a chick muscle primary cell culture system. When embryonic chick myoblasts are seeded onto collagen-coated petri dishes and grown in a medium containing horse-serum and embryo extract, the majority of the cells pass through an initial phase of proliferation (Fig. 4). The onset of terminal differentiation is marked by the fusion of myoblast cell membranes to form multi-nucleate syncytia of muscle fibres, the cessation of DNA biosynthesis and of cell division. There is also substantial increase in the activity of creatine phosphokinase, largely due to the de novo synthesis of a muscle specific isozyme of this protein. In this work we have made use of... 

Fig. 1. Activity gel analysis of poly(ADP-ribose) polymerase activity in crude extracts from different organisms. Lanes 1 Mj markers 2 HeLa cells 3 CHO cells 4 chick embryo 5 yeast 6 E. coli 7 rice cells 8 carrot cells...

Regulatory control of bacterial thymidylate synthetases by nucleotides has not been reported however, Lorenson et al. (7) investigated that of the chick embryo thymidylate synthetase and found that the 5 -mono-, di-, and triphosphates of adenosine, cytidine, guanosine, and uridine, and of their deoxyribosides, did not inhibit activity. Thus, the activity of the synthetase, from this source at least, does not seem to be subject to allosteric regulation by nucleotides. With crude extracts of Ehrlich ascites... 

Sinclair PR, Lambrecht R, Sinclair J (1987) Evidence for cytochrome P-450-mediated oxidation of uroporphyrinogen by cell-free liver extracts from chick embryos treated with 3-methylcholanthrene. Biochem Biophys Res Commun 146 1324-1329... 

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