Amino acid explants

Antibody, murine IgG-2b/K, against tobacco mosaic virus Suspension Nicotiana tabacum (tobacco) A. tumefaciens transformation of leaf explant CaMV 35 S Murine 15 4g g 1 wet weight (i) 45 4g g 1 wet weight (i) with amino acids 62... 

Scoccianti, V., Variations in the content of free and bound amino acids during dormancy and the first tuber cycle in Helianthus tuberosus tuber explants, Giom. Bot. Ital., 117, 237-245, 1983. 

Polyclonal antibodies have been prepared against partially purified rabbit mammary gland receptors [42-44], and have been used to demonstrate that the receptors really are involved in mediating the biological actions of prolactin. Anti-receptor antibodies that blocked binding of labelled prolactin were able to inhibit prolactin-stimulated casein synthesis and amino acid transport in rabbit mammary gland explants in vitro [43,45] (Fig. 4). They had no effect on the actions of insulin... 

Unlike other disease entities, excejit for canine cystinuria, no other nonhuman inherited amino acid disorders have been uncovered. In place of animal studies, increasing emphasis is being placed on the use of cultured explants of tissues removed from patients with hereditary metabolic disease. Cultured explants of skin, leukocytes, and erythrocytes have been used to study the metabolism of such disorders as citrullinemia, branch-chain ketoaciduria, cystinosis, homocystinuria, and isovalericacidemia (S18). 

As an initial approach to an analysis of the basis for the differences between embryo regions in their apparent sensitivity to protein starvation the breakdown of protein was studied (Klein et al., 1971). Chick embryos of 11-13 somites were exposed to C-labeled amino acids for 3 hours in buffered chick Ringer s salt solution. Explants were next cultured for 6 hours on semi-solid medium to reduce the level of free [ C]amino acids and to allow protein labeling to increase. They were then transferred to either whole egg homogenate growth medium or protein starvation medium. Explants were cultured for various periods up to 48 hours and dissected regions were analyzed for protein radioactivity and the radioactivity soluble in 5% trichloroacetic acid. Protein and DNA contents were also determined. 

Previously reported (Cohen et, 1972) experimental in vitro guinea pig liver explant studies from this laboratory tend to support the suggestion that the parent hydrolysate compounds and selective amino acids may be responsible for the abnormal liver function studies in children being treated with parenteral nutrition. In these studies four amino acids (glycine, leucine, isoleucine, threonine) were shown to increase serum GPT activity in organ culture but the mechanism for this elevated activity could not be further defined. 

---