scholarly journals Inhibition by α-methyl-norvaline of the uptake of valine and leucine into haemoglobin of the chick embryo

Development ◽  
1966 ◽  
Vol 15 (3) ◽  
pp. 291-295
Author(s):  
E. M. Deuchar ◽  
A. M. L. Dryland
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Chick Embryo ◽  
Special Interest ◽  
Chick Embryos ◽  
Area Vasculosa

We reported recently (Deuchar & Dryland, 1965) that α-methyl-norvaline, an amino acid whose structure resembles both valine and leucine, inhibits the uptake of these two normal amino- acids into protein in explanted chick embryos and is also itself incorporated into embryonic proteins. Since the first effect of α-methyl-norvaline that we had noted (Deuchar & Dryland, 1964) was a reduction in the quantity of haemoglobin formed in the cells of the area vasculosa, it was of special interest to see whether this inhibitor blocked the uptake of valine and/or leucine into haemoglobin in particular and whether it was at the same time taken up itself into haemoglobin. The results of experiments in which haemoglobin has been extracted from area vasculosa explants and the uptake of radioactively labelled amino acids into it has been measured, are reported here.

Effect of a Leucine Analogue on Incorporation of Glycine into the Proteins of Explanted Chick Embryos

Development ◽  
1958 ◽  
Vol 6 (2) ◽  
pp. 262-269
Author(s):  
Phyllis W. Schultz ◽  
Heinz Herrmann
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Chick Embryo ◽  
Total Protein ◽  
Nutrient Medium ◽  
Chick Embryos ◽  
Agar Gel ◽  
Egg Extract ◽  
Amino Acid Analogues

Amino acid analogues have been observed to give rise to abnormal forms of development of chick and amphibian embryos (Herrmann, 1953; Rothfels, 1954; Waddington & Sirlin, 1954; Feldman & Waddington, 1955; Herrmann, Rothfels-Konigsberg, & Curry, 1955). Assuming that these disturbances may be due to interference with the utilization of amino acids for protein formation, we have attempted an analysis of this effect by comparison of the protein contents and of the uptake of glycine into the proteins of chick embryo explants in the presence and absence of amino acid analogues. The results of such experiments are reported in this paper. The chick embryos used for explanation, the explantation technique, and the determination of total protein glycine and of tracer glycine were essentially the same as described previously (Herrmann & Schultz, 1958). The embryos were explanted at the 11–13 somite stage on to the surface of an agar gel containing egg extract as nutrient medium following the procedure given by Spratt (1947) as modified by Rothfels (1954).

Effects of some Amino-acid and Purine Antagonists on Chick Embryos

Development ◽  
1958 ◽  
Vol 6 (2) ◽  
pp. 365-372
Author(s):  
C. H. Waddington ◽  
Margaret Perry
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Effective Concentration ◽  
Metabolic Inhibitors ◽  
Chick Embryos ◽  
Purine Analogue ◽  
Know How ◽  
Naturally Occurring ◽  
Different Types ◽  
Strong Action

Several authors have studied the effects on developing embryos of substances which are analogues of naturally occurring amino-acids and purines, and known to act, in other systems, as metabolic inhibitors. It was emphasized by Waddington, Feldman, & Perry (1955) that any particular substance may exhibit very different effects in embryos of different types. They found, for instance, that the purine analogue 8-azaguanine has a very strong action in the chick and a much lesser one in the newt embryo. It is therefore necessary to consider the various classes of embryos separately. In this communication we shall be concerned only with chick embryos. Substances under test can be administered to such embryos by injection through the shell, as was done in the paper cited above With this technique it is impossible to know how much diffusion takes place of the substance injected, and one cannot therefore be certain of the effective concentration which actually reaches the embryo.

Inhibition by α-methyl-norvaline of valine and leucine uptake into protein in the chick embryo

Development ◽  
1965 ◽  
Vol 13 (3) ◽  
pp. 275-283
Author(s):  
E. M. Deuchar ◽  
A. M. L. Dryland
Keyword(s):  
Amino Acid ◽  
Chick Embryo ◽  
Recent Work ◽  
Leucine Uptake ◽  
Area Vasculosa ◽  
Abnormal Haemoglobin ◽  
Haemoglobin Molecule ◽  
Haemoglobin Synthesis

In an earlier publication (Deuchar & Dryland, 1964) it was reported that α-methyl-norvaline, an amino acid described by Ross et al. (1961), whose structure resembles that of both valine and leucine (see below), caused a visible reduction in the quantity of haemoglobin formed by explants of the area vasculosa of the 48-hr, chick embryo, as compared with controls explanted without the analogue present. The structure of the haemoglobin molecule in birds has not yet been fully worked out, but according to recent work (reviewed by Gratzer & Allison, 1960) there are at least four N-terminal valine groups, two of which have leucine adjacent to them. The inhibition of haemoglobin synthesis by α-methyl-norvaline might, therefore, be due to competition with valine or leucine for uptake into these terminal sites on the peptide chains of the globin. The analogue might itself be taken up in their place, forming an abnormal haemoglobin.

Impaired energy metabolism as an initial step in the mechanism for 6-aminonicotinamide-induced limb malformation

Development ◽  
1980 ◽  
Vol 59 (1) ◽  
pp. 217-222
Author(s):  
Yal C. Sheffield ◽  
Robert E. Seegmiller
Keyword(s):  
Amino Acid ◽  
Energy Metabolism ◽  
Chick Embryo ◽  
Chondroitin Sulfate ◽  
Atp Synthesis ◽  
Initial Step ◽  
Chick Embryos ◽  
Impaired Energy Metabolism ◽  
All Treatment

The analogue and antagonist of nicotinamide, 6-aminonicotinamide (6-AN), impairs cartilage formation and results in shortening of the limbs when administered to chick embryos. Studies have shown that 6-AN forms an abnormal NAD analogue which inhibits the activity of NAD-dependent enzymes associated with production of ATP. To determine if an effect on ATP synthesis might be associated with the mechanism of teratogenesis in the chick embryo, ATP levels of cartilage from day-8 chick embryos treated in vitro were assayed in relation to biosynthesis of protein, DNA and chondroitin sulfate. Incorporation of 35SO4− was inhibited by 6 h of treatment with 10 µg/ml of 6-AN, whereas incorporation of [3H]thymidine and [3H]amino acid was not inhibited until 12 h. Incorporation of [3H]- glucosamine was increased at all treatment times. A decrease in the level of ATP preceded any detectable inhibition of precursor incorporation. These results are consistent with the hypothesis that 6-AN inhibits chondroitin sulfate synthesis through a reduction in the level of ATP in chondrocytes.

scholarly journals Amino acid uptake in isolated chick embryo heart cells. Effect of insulin

1969 ◽  
Vol 114 (1) ◽  
pp. 97-105 ◽  
Author(s):  
G. G. Guidotti ◽  
Britta Lüneburg ◽  
A. F. Borghetti
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Chick Embryo ◽  
Isolated Heart ◽  
Cardiac Cells ◽  
Cell Permeability ◽  
Heart Cells ◽  
Acid Uptake ◽  
Aminoisobutyric Acid ◽  
Isolated Heart Cells

1. The preparation of cell suspensions by treatment of chick embryo hearts with collagenase at various stages of development is described. 2. Measurements of oxygen consumption, incorporation of labelled leucine into protein and accumulation of labelled α-aminoisobutyric acid against a concentration gradient indicated a long-lasting viability of the isolated heart cells in vitro; a satisfactory preservation of subcellular structures, including plasma membrane, was assessed by electron-microscopic examination. 3. The rate of α-aminoisobutyric acid accumulation by cardiac cells isolated from hearts at different stages of embryological development decreased with aging; insulin stimulated the intracellular accumulation of this amino acid analogue. 4. Insulin increased the uptake by isolated heart cells of several 14C-labelled naturally occurring amino acids; however, the fraction of amino acid taken up by the cells that was recovered free intracellularly, and therefore the concentration ratio (between intracellular water and medium), was enhanced by the hormone only with glycine, proline, serine, threonine, histidine and methionine. When isolated heart cells were incubated in the presence of a mixture of labelled amino acids, the addition of insulin increased the disappearance of radioactivity from the medium. 5. The general pattern of amino acid transport (in the absence and in the presence of insulin) in isolated cardiac cells was similar to that found in intact hearts, suggesting that the biological preparation described in this paper might be useful for studies of cell permeability and insulin action.

scholarly journals Preparation of polyribosome aminoacyl-transfer ribonucleic acid from the muscle of chick embryos.

1975 ◽  
Vol 147 (3) ◽  
pp. 473-477 ◽  
Author(s):  
M Nwagwu
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Sodium Dodecyl Sulphate ◽  
Ribonucleic Acid ◽  
Free Amino Acids ◽  
Free Amino ◽  
Sodium Dodecyl ◽  
Specific Radioactivity ◽  
Chick Embryos ◽  
Aminoacyl Transfer

A procedure for preparing polyribosome aminoacyl-tRNA free from contamination by supernatant aminoacyl-tRNA and free amino acids is described. Important features of the procedure are the use of acidic buffers to help protect the amino acid-tRNA linkage and the inclusion of sodium dodecyl sulphate, to inhibit ribonuclease activity. The specific radioactivity of polyribosome aminoacyl-tRNA is high within 30s and reaches a maximum in 2 1/2 min, well ahead of polyribosome peptides which, as described by Herrmann et al. (1971), attain maximum specific radioactivity in about 10 min.

scholarly journals The Incorporation of 14C from Sodium Acetate-2-14C into the Amino Acids of the Soil-Inhabiting Nematode, caenorhabditis briggsae

1960 ◽  
Vol 37 (3) ◽  
pp. 435-443
Author(s):  
W. L. NICHOLAS ◽  
ELLSWORTH C. DOUGHERTY ◽  
EDER LINDSAY HANSEN ◽  
OSMUND HOLM-HANSEN ◽  
VIVIAN MOSES
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Chick Embryo ◽  
Sodium Acetate ◽  
Liver Extract ◽  
Protein Hydrolysate ◽  
Cysteic Acid ◽  
Caenorhabditis Briggsae ◽  
Adequate Diet ◽  
Chick Embryo Extract

1. The nematode, Caenorhabditis briggsae was cultured axenicaily in a mixture of chick embryo extract, autoclaved liver extract and sodium acetate-2-14C. A protein hydrolysate was prepared from the worms and the eggs which were collected from the cultures. 2. Chromatography and radioautography were carried out in a study of the amino acid composition of the hydrolysate. The following amino acids were found labelled: aspartic acid, glutamic acid, alanine, proline, glycine, serine. Cystein and cystine were oxidized to cysteic acid which was also labelled. The following amino acids were not labelled: arginine, histidine, lysine, methionine, threonine, tyrosine, valine and the combined spot representing phenylalanine, leucine and isoleucine. Tryptophane would have been destroyed by our method of hydrolysis. 3. Since the labelled amino acids are synthesized by the worm, it is suggested, tentatively, that they are not required in an otherwise adequate diet. So far as the unlabelled amino acids are concerned, it is suggested, on the basis of the results of certain culture experiments (published separately) that, with the probable exception of tyrosine, they are essential in the diet of C. briggsae.

scholarly journals Insulin regulation of amino acid transport in mesenchymal cells from avian and mammalian tissues

1976 ◽  
Vol 160 (2) ◽  
pp. 281-286 ◽  
Author(s):  
G G Guidotti ◽  
A F Borghetti ◽  
G C Gazzola ◽  
M Tramacere ◽  
V Dall'asta
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Chick Embryo ◽  
Amino Acid Transport ◽  
Mesenchymal Cell ◽  
Mesenchymal Cells ◽  
Transport Systems ◽  
Acid Transport ◽  
Insulin Regulation ◽  
Mammalian Tissues

Insulin regulation of amino acid transport across the cell membrane was studied in a variety of mesenchymal cell directly isolated from avian and mammalian tissues or collected from confluent cultures. Transport activity of the principal systems of mediation in the presence and absence of insulin was evaluated by measuring the uptake of representative amino acids under conditions approaching initial entry rates. Insulin enhanced the transport rate of substrate amino acids from the A system(α-aminoisobutyric acid, L-proline, glycine, L-alanine and L-serine) in fibroblasts and osteoblasts from chick-embryo tissues, in mesenchymal cells (fibroblasts and smooth muscle cells) from immature rat uterus, in thymic lymphocytes from young rats and in chick-embryo fibroblasts from confluent secondary cultures. In these tissues, the uptake of amino acid substrates of transport systems L and Ly+ (L-leucine, L-phenylalanine, L-lysine) was not affected by the presence of the hormone. No insulin control of amino acid transport was detected in chick-embryo chondroblasts and rat peritoneal macrophages. These observations identify the occurrence of hormonal regulatory patterns of amino acid transport for different mesenchymal cells types and indicate that these properties emerge early during cell differentiation.

scholarly journals Kinetic analysis of insulin action on amino acid uptake by isolated chick embryo heart cells

1971 ◽  
Vol 122 (4) ◽  
pp. 409-414 ◽  
Author(s):  
G. G. Guidotti ◽  
A. F. Borghetti ◽  
Britta Lüneburg ◽  
G. C. Gazzola
Keyword(s):  
Carbon Dioxide ◽  
Amino Acids ◽  
Amino Acid ◽  
Chick Embryo ◽  
Transport Systems ◽  
Heart Cells ◽  
Acid Uptake ◽  
Maximal Velocity ◽  
Chick Embryo Heart ◽  
Embryo Heart

1. Isolated chick embryo heart cells were used to investigate the mode of action of insulin on the transport of three naturally occurring amino acids: l-proline, l-serine and glycine. Initial velocities of uptake were measured over a period of 5min with an 80-fold range of amino acid concentration. Corrections for amino acid diffusion, incorporation into protein and conversion into carbon dioxide were introduced. 2. The uptake processes approximated Michaelis–Menten kinetics within definite ranges of amino acid concentrations. A single transport system for proline and at least two transport systems for serine and glycine were detected. 3. The kinetic effects of insulin on transport systems for the amino acids tested were consistent with an acceleration of the maximal velocity of the process, without substantial changes in substrate concentration for half-maximal transport velocity. 4. These hormonal effects were not essentially altered by the corrections for amino acid incorporation into protein and conversion into carbon dioxide.

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