The influence of size and shape of kidney tissue from newborn and mature rats on the uptake of amino acid

1970 ◽  
Vol 48 (2) ◽  
pp. 152-154 ◽  
Author(s):  
William A. Webber
Keyword(s):  
Amino Acid ◽  
Concentration Gradient ◽  
Maximum Concentration ◽  
Kidney Tissue ◽  
Cortical Tissue ◽  
Aminoisobutyric Acid ◽  
Size And Shape ◽  
Maximum Gradient ◽  
Initial Uptake

The uptake of alpha-aminoisobutyric acid was studied in kidney cortical tissue of newborn and mature rats in the light of observations that the size and shape of the tissue pieces could influence concentrating ability. It was found that the pattern of differences in uptake by newborn and mature tissue was not altered by differences in the size and shape of tissue pieces. The initial uptake was more rapid in mature tissue but a higher maximum concentration gradient was ultimately achieved by newborn tissue. However, there was a difference in the maximum gradient achieved by newborn tissue depending on the configuration of the pieces of tissue incubated, and it is important, therefore, to know the morphology of the tissue being studied in interpreting the results of incubation studies.

Stimulation of transport of alpha-aminoisobutyric acid into the testes of immature mice in vivo by follicle-stimulating hormone

1982 ◽  
Vol 100 (1) ◽  
pp. 137-142
Author(s):  
Nila Oza ◽  
Sarah J. Meanock ◽  
A. G. Davies
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Amino Acid Transport ◽  
Specific Activity ◽  
Follicle Stimulating Hormone ◽  
Acid Transport ◽  
Aminoisobutyric Acid ◽  
Old Mice ◽  
Stimulation Of

Abstract. Groups of immature mice were injected sc with radiocarbon-labelled alpha-aminoisobutyric acid (AIB) after being given a single sc injection of hFSH or of 0.9% saline. As an index of the transport of AIB, the specific activity of isotope was measured in homogenates of testis and of liver. FSH treatment caused statistically significant increases in the specific activity of isotope in the testes and in the ratio of testicular to liver specific activity. The effect was greatest in 9-day-old mice injected with FSH 16 h before removal of the testes. Uptake of labelled AIB was not stimulated after administration of hCG or testosterone. Doses of cycloheximide sufficient to reduce the rate of protein synthesis by over 99% did not impair testicular uptake of labelled AIB or the influence of FSH on AIB uptake. These results suggest that FSH stimulates amino acid transport into cells of the immature testis and that this action is independent of the stimulatory effect of FSH on testicular protein synthesis.

Active Transport of α-Aminoisobutyric Acid by the Isolated Midgut of Hyalophora Cecropia

1972 ◽  
Vol 56 (1) ◽  
pp. 167-172
Author(s):  
SIGNE NEDERGAARD
Keyword(s):  
Amino Acid ◽  
Active Transport ◽  
Opposite Direction ◽  
Amino Acid Transport ◽  
Amino Acid Uptake ◽  
Acid Uptake ◽  
Acid Transport ◽  
Active Process ◽  
Aminoisobutyric Acid ◽  
Amino Acid Flux

1. The α-aminoisobutyric acid flux from lumen to blood of the isolated Cecropia midgut is around 17 µmole/h, while the amino acid flux in the opposite direction is on average 0.3 µmole/h. 2. The amino acid uptake is inhibited by lack of oxygen. It is suggested that the amino acid transport from lumen to blood is an active process. 3. The amino acid uptake is inhibited by short-circuiting the midgut potential, indicating that there is no direct correlation between the active transport of potassium and the uptake of the amino acid by the midgut.

scholarly journals Imaging of Long-Distance α-Aminoisobutyric Acid Translocation Dynamics during Resource Capture by Serpula lacrymans

2008 ◽  
Vol 74 (9) ◽  
pp. 2700-2708 ◽  
Author(s):  
Monika Tlalka ◽  
Mark Fricker ◽  
Sarah Watkinson
Keyword(s):  
Amino Acid ◽  
Nutrient Dynamics ◽  
Photon Counting ◽  
Brown Rot ◽  
Experimental Period ◽  
Long Distance ◽  
Aminoisobutyric Acid ◽  
Wood Resource ◽  
High Concentrations ◽  
Serpula Lacrymans

ABSTRACT α-Aminoisobutyric acid (AIB) is a nonmetabolized amino acid analogue of alanine, which at low (μM) concentrations acts as a tracer for amino acid movements. At high concentrations (mM), it competitively inhibits membrane transport and metabolism of protein amino acids and acts as a systemic translocated inhibitor of mycelial extension in fungi. AIB can control mycelial spread of the basidiomycete Serpula lacrymans, the cause of brown rot of wood in buildings. However, it is not known how effectively the inhibitor is distributed throughout the mycelium. Realistically heterogeneous microcosms, in which the fungus grew across nutritionally inert sand to colonize discrete wood resources, were used to investigate patterns of inhibition and translocation following local application of AIB. At a 0.1 M concentration, locally applied AIB caused immediate arrest of extension throughout the whole mycelium, maintained for a 6-week experimental period. The dynamics of translocation of subtoxic amounts of [1-14C]AIB ([14C]AIB) were mapped by photon-counting scintillation imaging in conjunction with destructive harvest to establish the velocity, direction, and rate of translocation and the extent of [14C]AIB reallocation accompanying the invasion of fresh wood. Locally applied [14C]AIB was distributed throughout complex mycelial networks within 2 h of application, becoming localized in growing margins by 12 h. Encounter with a fresh wood resource triggered a widespread response, causing withdrawal of [14C]AIB from throughout the network, accompanied by accumulation in the newly colonized wood and associated mycelium. The results are discussed in the context of nutrient dynamics in wood decomposer fungi and the mechanism of the amino acid reallocation response.

scholarly journals Chemoenzymatic synthesis of polypeptides containing the unnatural amino acid 2-aminoisobutyric acid

2017 ◽  
Vol 53 (53) ◽  
pp. 7318-7321 ◽  
Author(s):  
Kousuke Tsuchiya ◽  
Keiji Numata
Keyword(s):  
Amino Acid ◽  
Ethyl Ester ◽  
Unnatural Amino Acid ◽  
Chemoenzymatic Synthesis ◽  
Aminoisobutyric Acid

Polypeptides containing 2-aminoisobutiryc acid (Aib) as an unnatural amino acid were synthesized via chemoenzymatic polymerization of the tripeptide ethyl ester AlaAibAla-OEt.

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 Intracellular monosaccharide and amino acid concentrations and activities and the mechanisms of insulin action.

1981 ◽  
Vol 1 (9) ◽  
pp. 769-784 ◽  
Author(s):  
S B Horowitz ◽  
T W Pearson
Keyword(s):  
Amino Acid ◽  
Activity Coefficients ◽  
Membrane Properties ◽  
Small Cells ◽  
Internal Reference ◽  
Concentration Data ◽  
Aminoisobutyric Acid ◽  
Solute Exclusion ◽  
Water As Solvent ◽  
Concentration Asymmetry

Current amino acid and monosaccharide transport models are based on an assumption which equates the intracellular chemical activity of a solute with its concentration. This assumption was tested for alpha-aminoisobutyric acid and 3-O-methylglucose in a giant cell, the amphibian oocyte, by using recently developed cryomicrodissection and internal reference phase techniques. We found the following. (i) alpha-Aminoisobutyric acid and 3-O-methylglucose activities were much greater in cytoplasm than was suggested by concentration data; i.e., activity coefficients were higher than in ordinary water solutions. This is attributable to the inaccessibility of considerable water as solvent (solute exclusion). (ii) Solute concentrations varied regionally as follows: nucleus > > animal cytoplasm > vegetal cytoplasm. Insulin increased the nucleus/cytoplasm concentration asymmetry, apparently by increasing cytoplasmic solute exclusion. (iii) Nuclear activity coefficients more closely resembled those of ordinary saline solutions so that nucleus/ extracellular concentration ratios reflected transmembrane activity gradients better than did cytoplasm (or whole cell)/extracellular ratios. (iv) Mediated passive alpha-aminoisobutyric acid and 3-O-methylglucose transport were constituent oocyte membrane properties. Membrane active transport was initiated with time (in the presence of substrate) and by insulin. (v) Increased temperature mimicked insulin in enhancing transmembrane alpha-aminoisobutyric acid activity gradients and increasing the nucleus/cytoplasm concentration asymmetry. These results indicated that concentration data are a misleading measure of cellular amino acid and monosaccharide activity; some consequences of this observation were explored. A model is proposed in which cell water has reduced solvent capacity or is compartmentalized (considered less likely) and is susceptible to physiological modulation. The model accounts for many observations in small cells, suggesting generality of the exclusion phenomenon and a previously unrecognized metabolic control mechanism.

Transport of l-tyrosine by the small intestine in vitro

1960 ◽  
Vol 199 (1) ◽  
pp. 127-130 ◽  
Author(s):  
Edmund C. C. Lin ◽  
T. Hastings Wilson
Keyword(s):  
Small Intestine ◽  
Amino Acid ◽  
Transport System ◽  
Concentration Gradient ◽  
Animal Species

l-Tyrosine was absorbed against a concentration gradient by sacs of isolated small intestine obtained from several animal species. During absorption the tissue segments accumulated the amino acid to concentrations as high as nine times that in the suspending medium. In the case of the hamster the rate of transport was maximal in the mid portion of the small intestine. Studies on specificity of the transport system showed that l-tyrosine and dl-meta-tyrosine were transported while no activity was observed with d-tyrosine, dl-ortho-tyrosine, and 3,5-diiodo-l-tyrosine. Transport of l-tyrosine was inhibited by l-phenylalanine and l-methionine but not by d-phenylalanine. High tyrosine diet did not alter the rate of the in vitro transport of this amino acid in the rat.

Corticosteroids and accumulation of C14-labeled amino acids and histamine by isolated rat diaphragm

1960 ◽  
Vol 199 (4) ◽  
pp. 715-718 ◽  
Author(s):  
Ira G. Wool
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Rat Diaphragm ◽  
Amino Acid Analogue ◽  
Rate Of Penetration ◽  
Aminoisobutyric Acid ◽  
Acid Analogue ◽  
Isolated Rat

The rate of penetration and the magnitude of accumulation of several utilized C14-amino acids, of the amino acid analogue, α-aminoisobutyric acid-1-C14, and of C14-histamine was measured in intact and cut isolated rat diaphragm. Adrenalectomy was without effect on the rate of entry of the amino acids or of histamine; cortisone administration (2 mg/day) depressed the accumulation of the utilized amino acids, of α-aminoisobutyric acid and of histamine.

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