Yolk sacs

Oncorhynchus mykiss) yolk sac fry. Science of the Totat Environment, 103 229-243. 

A further interesting phenotype identified in SDF-1/CXCR4 knockout mice is a deficiency in blood vessel development, initially observed in the gastrointestinal system (Tachibana et al. 1998). Consistent with such observations, CXCR4 receptors have been shown to be expressed by hemangioblasts, the earliest common precursor to hematopoietic and endothelial stem cells, found in yolk sac... 

This group of microorganisms shares with chlamydias the property of growing only in living tissue. Rickettsiae occur as small (0.3 x 0.25/mi) rod-shaped or coccoid cells. They can be stained by special procedures. Division is by binary fission. They may be cultivated in the blood of laboratory animals or in the yolk sac of the embryo of the domestic fowl, and it is by this method that the organism is grown to produce vaccines. 

Moore MA, Metcalf D. Ontogeny of the haemopoietic system yolk sac origin of in vivo and in vitro colony forming cells in the developing mouse embryo. Br J Haematol 1970 18(3) 279-296. 

Ins 1 jlns2 (19/7) Paternal (yolk sac) Peptide hormone Fetal GR phenotypic Duvillie et al 1997 effect of imprinting undefined... 

Ferritins have been found in a wide range of species, and sequence data - some, as in the first ever sequence of horse spleen apoferritin (Heusterspreute and Crichton, 1981) determined by direct methods, but many now by DNa sequencing 1, have been deposited for more than 70 ferritins. They vary in length from 154-185 residues per subunit. Some ferritins have N-terminal extensions which lie on the outside of the assembled shell and target the ferritin to a specific destination such as plastids in plants and yolk sac in snails (Andrews etah, 1992 Lobreaux etah, 1992). For example, pea ferritin is synthesized with an N-terminal extension of 75 residues, which is missing from the mature protein. The first part of this extension is a chloroplast-targetting sequence of 47 residues, which is lost on entry into the plastid. The second part, an extension peptide, is lost prior to assembly of the... 

AFP is a 70 kDa glycoprotein found in the circulatory system of the developing foetus. It is synthesized primarily by the yolk sac and (foetal) liver. AFP is present only in vanishing low quantities in the serum of adults (where it is replaced by serum albumin). Elevated adult serum levels of this marker are often associated with various cancers of the liver, as well as germ cell tumours. It is also sometimes expressed by gastric and pancreatic cancer cells. Although a useful tumour marker, increased serum AFP levels also often accompany cirrhosis and some other non-cancerous liver diseases. 

Yolk-sac fry exposed to 10 pg Pb/L Zebrafish, Brachydanio rerio Embryos exposed for 16 days Adverse effects on growth and development in groups hatched and maintained in soft, acid water 46... 

Sayer, M.D.J., J.P. Reader, and R. Morris. 1989. The effect of calcium concentration on the toxicity of copper, lead and zinc to yolk-sac fry of the brown trout, Salmo trutta L., in soft, acid water. Jour. Fish Biol. 35 323-332. 

YOLK SAC INJECTION (pg Hg/egg) Chicken Methyl 15.0 Single dose Some deaths 13... 

Eggs were exposed in freshwater to 4 pg Ag/L for 14 days prior to hatch. After hatching, larvae were exposed to 4 pg Ag/L in salt water for 14 days during yolk-sac resorption. Fry were then transferred to uncontaminated salt water and fed a high metals diet for 64 days (diet At end of study, experimentals had a small, but significant, decline in survival. Just prior to transfer to uncontaminated salt water, experimentals contained 62 pg Ag/kg whole body DW vs. 4 in controls. After 64 days in uncontaminated salt water, whole alevins contained 18 pg Ag/kg DW vs. 4 in controls 29... 

Rainbow trout, Oncorhynchus mykiss 0.2-1.0 Exposure of yolk-sac fry for 110 days produced liver dysfunction, reduced growth, and altered blood chemistry no deaths 8, 21... 

Seinen, W., T. Helder, H. Vemij, P. Penninks, and P. Leeuwangh. 1981. Short term toxicity of tri-n-butylt-inchloride in rainbow trout (Salmo gairdneri Richardson) yolk sac fry. Sci. Total Environ. 19 155-166. 

Yolk-sac fry 4.9 40% with noncalcified vertebrae center all dead in 18 days at phi 4.5 and soft water 75... 

Toxicosis occurred in yolk-sac larvae within 24 h, as judged by significant reductions in content of RNA and protein however, effects were not measurable in 96 h, suggesting development of partial tolerance 29... 

Cormorant, Phalacrocorax carbo, the Netherlands April-May 1989 two colonies yolk-sac of hatchlings... 

Hatchability was reduced at 226 and 302 ng/kg egg, with greatest mortality at the sac-fry stage. In all TCDD groups, sac fry that died developed subcutaneous yolk-sac edema. There were no deaths at egg concentrations of 34 ng/kg and some deaths at 55 ng/kg... 

O. mykiss 40 100% mortality during exposure from fertilization to yolk-sac absorption (72 days) 28... 

Great cormorant, Phalacrocorax carbo Netherlands yolk sac ... 

Embryos of the common tem (Sterna hirundo) from eight colonies in the Netherlands and Belgium were analyzed for PAHs in May-July 1991. In general, eggs containing embryos with elevated PAH concentrations in the yolk sac and with elevated hepatic EROD activity levels were laid later, had a more prolonged incubation period, were of smaller volume, and produced smaller chicks (Murk et al. 1996). 

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