EFFECT OF VARIOUS AMINO ACIDS ON THE INCORPORATION OF 14C-L-LEUCINE IN THE TISSUE PROTEINS OF NORMAL AND DYSTROPHIC MICE

1967 ◽  
Vol 45 (12) ◽  
pp. 1985-1993 ◽  
Author(s):  
Louis Berlinguet ◽  
Uma Srivastava
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Actinomycin D ◽  
Daily Injection ◽  
Normal Muscle ◽  
Dystrophic Muscle ◽  
Time Intervals ◽  
Parallel Group ◽  
Continuous Injection ◽  
Dystrophic Mice

Normal and dystrophic mice received daily injections of either water, saline, glutamate, aspartate, glycine, ACPC, or actinomycin D for 5 days. One parallel group of animals received no injections and served as control. On the 6th day after the start of the experiment, all the animals received an intravenous injection of 14C-L-leucine and were killed at various time intervals, ranging from 4 h to 12 days. Daily injections of water or saline to the animals did not cause any change in the incorporation of 14C-L-leucine into various tissue proteins. Glutamate administration increased the retention of 14C-L-leucine in normal muscle but not in dystrophic muscle. A daily injection of aspartate increased the retention of the radioactive amino acid in both normal and dystrophic muscles, the higher increase being found in the dystrophic muscle. Administration of glycine reduced the turnover of proteins in both normal and dystrophic muscles. ACPC (1-amino-cyclopentanecarboxylic acid) or actinomycin D administration caused a decrease in the incorporation of 14C-L-leucine into normal and dystrophic muscles.The continuous injection of glutamate or aspartate for 8 days after the 14C-L-leucine administration caused a very large increase in the retention of the labelled amino acid into the proteins of various tissues of normal and dystrophic mice. It is concluded that variations in the amino acid pools can modify the turnover of proteins, which can be of importance in muscular dystrophy.

BIOCHEMICAL CHANGES IN PROGRESSIVE MUSCULAR DYSTROPHY: VI. INCORPORATION OF URIDINE-2-14C INTO RNA OF VARIOUS TISSUE OF NORMAL AND DYSTROPHIC MICE

1967 ◽  
Vol 45 (9) ◽  
pp. 1419-1425 ◽  
Author(s):  
Uma Srivastava
Keyword(s):  
Muscular Dystrophy ◽  
Soluble Fraction ◽  
Normal Liver ◽  
Biochemical Changes ◽  
Normal Muscle ◽  
Dystrophic Muscle ◽  
Progressive Muscular Dystrophy ◽  
Dystrophic Mice

Normal and dystrophic mice were injected intravenously with uridine-2-14C at various stages of the disease. Radioactivity in the acid-soluble fraction of most of the tissues studied was unchanged or not significantly different in dystrophic animals. In vivo incorporation of uridine-2-14C into RNA increased in dystrophic muscle as compared to normal muscle at 30 days, remained the same at 60 days, and was reduced at 90 days. Similar results were also observed on the in vitro incorporation of uridine-2-14C catalyzed by homogenates of normal and dystrophic muscle. Dystrophic brain and pancreas showed a decrease in the incorporation at each stage investigated as compared to controls. No change in the incorporation was noted in dystrophic and normal liver, kidney, spleen, and heart. The decrease in uridine-2-14C incorporation in dystrophic muscle at 90 days could be due to an increased RNA content. Such a phenomenon was explained as due to infiltration of dystrophic muscle by invading macrophages.It is concluded that the metabolism of RNA is not decreased in the dystrophic muscle in preliminary stages of the disease as compared to the control.

scholarly journals Release of selected amino acids from zinc carriers

2016 ◽  
Vol 66 (2) ◽  
pp. 269-277
Author(s):  
Renata Dyja ◽  
Barbara Dolińska ◽  
Florian Ryszka
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Molar Ratio ◽  
Time Intervals ◽  
Solubility In Water ◽  
First Order ◽  
First Order Kinetics ◽  
Acid Release ◽  
Co Precipitation ◽  
Low Solubility

Abstract The paper deals with the results of an investigation of the release of selected amino acids (histidine, tryptophan, tyrosine) from model suspensions prepared by co-precipitation with zinc chloride. It has been proven that the influence of the Zn(II)/amino acid molar ratio on dissolution profiles of the tested amino acids and dissolution half-life (t1/2) of histidine or tryptophan is significant. The amount of amino acid in the dispersed phase (supporting dose) is a determinant of the amino acid release profile. There is a minimal supporting dose (30.0 μmol of histidine or 17.4 μmol of tryptophan) that provides release of similar amounts of amino acid (4.1–4.6 μmol of histidine or 8.7–9.9 μmol of tryptophan) after the same time intervals. The tyrosine release profiles follow first order kinetics since the supporting dose (0.9–11.2 μmol) is limited by the tyrosine low solubility in water.

scholarly journals TOLERANCE TO AMINO ACID MIXTURES AND CASEIN DIGESTS GIVEN INTRAVENOUSLY

1945 ◽  
Vol 81 (5) ◽  
pp. 439-448 ◽  
Author(s):  
S. C. Madden ◽  
R. R. Woods ◽  
F. W. Shull ◽  
J. H. Remington ◽  
G. H. Whipple
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Glutamic Acid ◽  
Acid Content ◽  
Essential Amino Acids ◽  
Daily Injection ◽  
Nitrogen Requirement ◽  
Amino Acid Mixtures ◽  
Nitrogen Rates ◽  
Crystalline Amino Acids

Several synthetic mixtures of natural and racemic crystalline amino acids suitable for the daily nitrogen requirement are tested in dogs for their tolerance upon intravenous injection. Certain mixtures of the ten essential amino acids plus non-essential amino acids exclusive of glutamic acid are accepted without any obvious sign of disturbance even at rates above 10 mg. nitrogen per kilo per minute for quantities greater than 300 mg. per kilo. One such mixture consists in parts per 100 of dl-threonine 7, dl-valine 15, l(-)-leucine 10.9, dl-isoleucine 9.9, l(+)-lysine· HCl·H2O 10.9, dl-tryptophane 3, dl-phenylalanine 9.9, dl-methionine 6, l(+)-histidine·HCl·H2O 5, l(+)-arginine-HCl 5, glycine 9.9, dl-α-alanine 4, dl-serine 2, l(-)-cystine 0.5, and l(-)-tyrosine 1. In addition other well tolerated mixtures included the prolines. When glutamic acid, natural or racemic, is included in similar mixtures vomiting reactions frequently occur at nitrogen rates above 4 mg. per kilo per minute. Vomiting almost always occurs on the first daily injection containing glutamic acid and usually on any subsequent injection containing more than 100 mg. glutamic acid per kilo unless given very slowly. Upon the addition of glycine certain mixtures of the ten essential amino acids show an improved tolerance. Two casein digests tested usually produced vomiting at injection rates above 2 mg. nitrogen per kilo per minute, probably because of their glutamic acid content. No serious reaction has ever occurrred to any mixture of amino acids or casein digest tested. Elimination of minor reactions such as vomiting appears possible and desirable for greater usefulness of these solutions in parenteral feeding.

PROTEOLYTIC ENZYMES IN NORMAL AND DYSTROPHIC MOUSE MUSCLE

1966 ◽  
Vol 44 (5) ◽  
pp. 613-623 ◽  
Author(s):  
L. Berlinguet ◽  
U. Srivastava
Keyword(s):  
Proteolytic Enzymes ◽  
Chemical Change ◽  
Optimum Conditions ◽  
Normal Muscle ◽  
Dystrophic Muscle ◽  
Muscle Enzymes ◽  
Mouse Muscle ◽  
Ph Values ◽  
Dystrophic Mouse ◽  
Dystrophic Mice

Proteolytic enzymes extracted from normal and dystrophic mouse muscle were studied, and optimum conditions for their activities were established. It was found that these enzymes were active at two pH values, 7.5 and 9. In normal and dystrophic mice, the enzymatic activity increased with age. When the activities of dystrophic muscle enzymes were compared with those of normal muscle enzymes, the increase was most significant in animals 60–90 days of age. The results obtained when the enzymes extracted from normal or dystrophic muscle were incubated with substrates from normal or dystrophic muscle indicate that the defect in the muscle is due to an increase in the activities of the proteolytic enzymes rather than to a chemical change in the muscle proteins.

Defect in regulation of membrane transport of monosaccharides in dystrophic muscle

1979 ◽  
Vol 57 (7) ◽  
pp. 695-701 ◽  
Author(s):  
J. Elbrink
Keyword(s):  
Plasma Membranes ◽  
Sugar Transport ◽  
Normal Muscle ◽  
Dystrophic Muscle ◽  
Variable Effect ◽  
Cardiomyopathic Hamsters ◽  
Uncoupling Of Oxidative Phosphorylation ◽  
Dystrophic Mice ◽  
Normal Controls ◽  
Glucose Analogue

The penetration of a nonmetabolized glucose analogue, 3-O-methyl-D-glucose, across the plasma membranes of tissues from dystrophic mice and cardiomyopathic (dystrophic) hamsters has been compared with that of normal controls. Under basal conditions the penetration of test sugar was similar in lens and diaphragm of normal and dystrophic 129/ReJ mice. Stimulation of sugar transport by 2,4-dinitrophenol did occur in normal but not in dystrophic diaphragm. A submaximal concentration of insulin had a more variable effect in dystrophic than in normal muscle while a supramaximal concentration of the hormone increased the uptake of the glucose analogue to an equal extent in the two tissues. In the BIO 14.6 strain of cardiomyopathic hamsters, uncoupling of oxidative phosphorylation did not increase sugar transport in extensor digitorum longus muscles, while the normal effect was observed in dystrophic soleus and in both these muscles of the random bred controls. The absence of an effect by a condition simulating anoxia suggests that in dystrophy, certain muscles are unable to accelerate the entry of glucose when this is required.

RELATIONSHIP BETWEEN DIETARY PROTEIN CONTENT AND PLASMA AMINO ACIDS IN SHEEP FED PURIFIED DIETS

1973 ◽  
Vol 53 (3) ◽  
pp. 455-464
Author(s):  
A. CECYRE ◽  
G. M. JONES ◽  
J.-M. GAUDREAU
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Time Intervals ◽  
Dietary Nitrogen ◽  
Low Protein ◽  
Limiting Amino Acid ◽  
Nonessential Amino Acids ◽  
Amino Acid Concentrations

Semipurified diets, varying in crude protein (CP) content (6, 10, 15, and 22% CP), were each fed to one wether and plasma amino acid (PAA) concentrations were determined at 0, 15, 30, 60, 120, 240, and 360 min postfeeding. Total essential amino acid concentrations for the 6, 10, and 15% CP rations were 47.2, 76.4, and 72.9 μmol/ml, while nonessential amino acids totalled 88.3, 110.0, and 104.9 μmol/ml, respectively. In general, PAA concentrations were depressed by the low protein diet, except for glycine, which was elevated, and threonine and alanine, which were not affected. PAA concentrations gradually decreased with time after feeding. There was no evident relationship between PAA levels and amount of feed consumed at these time intervals. Lysine was probably the most limiting amino acid, based upon PAA concentrations on the low protein diet compared to average PAA levels for all diets. PAA concentrations reflected dietary nitrogen content. The results suggest that PAA levels were not involved in the regulation of voluntary intake when the diet contained sufficient protein to meet the requirements of the animal.

scholarly journals Recessive constitutive mutant Chinese hamster ovary cells (CHO-K1) with an altered A system for amino acid transport and the mechanism of gene regulation of the A system.

1984 ◽  
Vol 4 (4) ◽  
pp. 799-808 ◽  
Author(s):  
J Moffett ◽  
E Englesberg
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Chinese Hamster Ovary ◽  
Amino Acid Transport ◽  
Actinomycin D ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Acid Transport ◽  
Ovary Cells ◽  
Proline Transport

Chinese hamster ovary cells (CHO-K1) starved for 24 h for amino acids show a severalfold increase in velocity of proline transport through the A system (Vmax is five times that of unstarved cells). This increase is inhibited by cycloheximide, actinomycin D, N-methyl-alpha-amino isobutyric acid (MeAIB, a non-metabolizable specific A system amino acid analog), and by other amino acids that are generally transported by the A system. However, transport by the A system is not a prerequisite for this repression, and all compounds that have affinity for the A system do not necessarily act as "co-repressors." The addition of proline, MeAIB, or other amino acids, as described above, to derepressed cells results in a rapid decrease in A system activity. As shown with proline and MeAIB, this decrease in activity is in part due to a rapid trans-inhibition and a slow, irreversible inactivation of the A system. Neither process is inhibited by cycloheximide or actinomycin D. Alanine antagonizes the growth of CHO-K1 pro cells by preventing proline transport, and alanine-resistant mutants (alar) have been isolated (Moffett et al., Somatic Cell Genet. 9:189-213, 1983). alar2 and alar4 are partial and full constitutive mutants for the A system and have two and six times the Vmax for proline uptake by the A system, respectively. The A system in alar4 is also immune to the co-repressor-induced inactivation. Both alar2 and alar4 phenotypes are recessive. Alar3 shows an increase in Vmax and Km for proline transport through the A system, and this phenotype is codominant. All three mutants have a pleiotropic effect, producing increases in activity of the ASC and P systems of amino acid transport. This increase is not due to an increase in the Na+ gradient. The ASC and P phenotypes behave similarly to the A system in hybrids. A model has been proposed incorporating these results.

Correlations between the amino acid pools of Hymenolepis diminuta and the rat intestine

1975 ◽  
Vol 53 (3) ◽  
pp. 320-331 ◽  
Author(s):  
D. F. Mettrick
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Protein Biosynthesis ◽  
Hymenolepis Diminuta ◽  
Amino Acid Pool ◽  
Acid Uptake ◽  
Rat Intestine ◽  
Time Intervals ◽  
Acid Pool ◽  
High Degree

The composition of the free and protein amino acid pools of the rat intestine and of 16-day-old Hymenolepis diminuta have been determined at 1000 and 1600 h under ad libitum feeding conditions. The molar concentration (μmol/g dry-wt.) of the total intestinal and worm amino acid pools remained constant through time, although quantitatively individual amino acids differed significantly. All of 16 amino acids determined differed significantly in the comparisons between the intestinal and worm amino acid pools and between the time intervals. There was a high degree of correlation between the time intervals. There was also a high degree of correlation between the intestinal and worm pools based on their quantitative ranking, supporting the conclusion that there is little selective capacity involved in amino acid uptake by H. diminuta.Between 1000 and 1600 h the total worm amino acid pool increased by 73 μmol, mainly as a result of an increase in protein amino acids, indicating that worm protein biosynthesis was not inhibited by the changes in the intestinal pools. As the luminal free amino acid pool averaged only 20 μmol over this period, uptake by the worms would be equivalent to 60% of the luminal pool per hour.This high level of nutritional predation by the worms may be tolerated by the host because of extensive mucosal peptide absorption. A similar ability by the worms may explain why they can also tolerate the extensive amino acid fluctuations and fluxes that have been demonstrated between helminth and lumen.

Ca2+-dependent slow action potentials in normal and dystrophic mouse skeletal muscle

1983 ◽  
Vol 245 (5) ◽  
pp. C415-C422 ◽  
Author(s):  
L. M. Kerr ◽  
N. Sperelakis
Keyword(s):  
Skeletal Muscle ◽  
Action Potentials ◽  
Osmotic Shock ◽  
Muscle Fibers ◽  
Normal Muscle ◽  
Dystrophic Muscle ◽  
Recording Technique ◽  
Mammalian Muscle ◽  
Dystrophic Mice ◽  
Slow Action Potentials

Slowly rising action potentials (APs), previously described in amphibian skeletal muscle, were examined in skeletal muscle of normal and dystrophic mice (129/ReJ strain). A standard two-microelectrode recording technique was used. Muscles were bathed in a solution that was Cl- free (methanesulfonate substituted), high in K+ (20 mM), and contained 15 mM tetraethylammonium. The slow APs were elicited under conditions in which the fast Na+ channels were voltage inactivated (by partial depolarization) and in which the external Na+ concentration was only 10 mM. Increases in external Ca2+ concentration produced increases in slow AP amplitude and duration. Mn2+ (4 mM), La3+ (4 mM), and detubulation with osmotic shock blocked the slow APs. When slow APs were generated at 30-s intervals, their amplitude stayed constant. When they were generated at 15-s intervals, their amplitude decreased progressively and then fell to zero by the 11th stimulus. The Ca antagonists verapamil (10(-5) M) and bepridil (10(-5) M) caused this decrease in amplitude to occur more quickly. Voltage inactivation of the slow APs occurred between -45 and -10 mV. Slow APs recorded from dystrophic muscle fibers were decreased in amplitude and duration compared with those in normal fibers, and there was a reduced incidence of occurrence; 96% of the fibers in normal muscle exhibited slow APs compared with only 46% of dystrophic muscle fibers. In summary, slow Ca2+ APs in mammalian muscle are similar to those in cardiac and amphibian skeletal muscle, and these slow APs are depressed in dystrophic skeletal muscle.

Thiol protease and cathepsin D activities in selected tissues and cultured cells from normal and dystrophic mice

1987 ◽  
Vol 65 (2) ◽  
pp. 124-129 ◽  
Author(s):  
P. Gopalan ◽  
M. J. Dufresne ◽  
A. H. Warner
Keyword(s):  
Protease Inhibitors ◽  
Protease Activity ◽  
Cathepsin D ◽  
Normal Muscle ◽  
Dystrophic Muscle ◽  
Thiol Protease ◽  
Hindlimb Muscle ◽  
Protease Activation ◽  
Dystrophic Mice ◽  
Cathepsin D Activity

Thiol protease and cathepsin D activities were studied in extracts from hindlimb muscle of 60-day-old normal and dystrophic mice, strain 129 ReJ, and from cultured normal and dystrophic cells. Total thiol protease activity in dystrophic muscle extracts was 3.5 times higher than in normal muscle extracts, while cathepsin D, activity was 2.2 times greater in dystrophic muscle compared with normal muscle. Activation (pH 4.5, 30 °C) of latent thiol protease activity in extracts of muscle occurred concomitant with the inactivation or dissociation of endogenous protease inhibitors. Thiol protease assays revealed a higher ratio of active to inactive protease activity in extracts from dystrophic muscle than from normal muscle. Cultured myoblasts (L69/1) were found to contain 30-fold more thiol protease(s) and 6-fold more cathepsin D activity than whole muscle. Cells established from dystrophic muscle and grown in culture for periods up to 6 months were more responsive to thiol protease activation conditions than similar cultures derived from normal muscle. From data on the rate and extent of thiol protease activation in extracts from dystrophic cells and hindlimb muscle compared with normal tissue, it appears that cells and tissues from dystrophic mice contain a lower level of protease inhibitors than cells and tissues from normal mice.

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