scholarly journals Arteriovenous differences for amino acids across control and acid-secreting rat stomach in vivo

1983 ◽  
Vol 210 (2) ◽  
pp. 451-455 ◽  
Author(s):  
N G Anderson ◽  
P J Hanson
Keyword(s):  
Amino Acids ◽  
Ammonia Concentration ◽  
Branched Chain Amino Acids ◽  
Stomach Wall ◽  
Rat Stomach ◽  
Branched Chain Amino Acid ◽  
Acid Secreting ◽  
Branched Chain ◽  
Stimulation Of

1. A method is described for measuring arteriovenous differences across the rat stomach in vivo. 2. Notable results were the uptake of branched-chain amino acids, the uptake of arginine, which was approximately balanced by an output of ornithine, and the output of alanine. 3. The fractional extraction of glutamine from the blood by the stomach wall of pentagastrin-stimulated rats was 4.7%. 4. The arteriovenous differences for ammonia depended upon the blood ammonia concentration. 5. Arteriovenous differences were not affected by the stimulation of acid secretion with pentagastrin. 6. It is concluded that the high activity of branched-chain-amino-acid aminotransferase (EC 2.6.1.42) in the gastric mucosa is associated with metabolism of these amino acids, but that the stomach wall is a less avid user of glutamine than is the small intestine.

scholarly journals Inactivation of the ilvB1 gene in Mycobacterium tuberculosis leads to branched-chain amino acid auxotrophy and attenuation of virulence in mice

Microbiology ◽  
2009 ◽  
Vol 155 (9) ◽  
pp. 2978-2987 ◽  
Author(s):  
Disha Awasthy ◽  
Sheshagiri Gaonkar ◽  
R. K. Shandil ◽  
Reena Yadav ◽  
Sowmya Bharath ◽  
...  
Keyword(s):  
Amino Acids ◽  
Mycobacterium Tuberculosis ◽  
Amino Acid ◽  
Mutant Strain ◽  
Branched Chain Amino Acids ◽  
Branched Chain Amino Acid ◽  
Branched Chain ◽  
Kinetics Of

Acetohydroxyacid synthase (AHAS) is the first enzyme in the branched-chain amino acid biosynthesis pathway in bacteria. Bioinformatics analysis revealed that the Mycobacterium tuberculosis genome contains four genes (ilvB1, ilvB2, ilvG and ilvX) coding for the large catalytic subunit of AHAS, whereas only one gene (ilvN or ilvH) coding for the smaller regulatory subunit of this enzyme was found. In order to understand the physiological role of AHAS in survival of the organism in vitro and in vivo, we inactivated the ilvB1 gene of M. tuberculosis. The mutant strain was found to be auxotrophic for all of the three branched-chain amino acids (isoleucine, leucine and valine), when grown with either C6 or C2 carbon sources, suggesting that the ilvB1 gene product is the major AHAS in M. tuberculosis. Depletion of these branched chain amino acids in the medium led to loss of viability of the ΔilvB1 strain in vitro, resulting in a 4-log reduction in colony-forming units after 10 days. Survival kinetics of the mutant strain cultured in macrophages maintained with sub-optimal concentrations of the branched-chain amino acids did not show any loss of viability, indicating either that the intracellular environment was rich in these amino acids or that the other AHAS catalytic subunits were functional under these conditions. Furthermore, the growth kinetics of the ΔilvB1 strain in mice indicated that although this mutant strain showed defective growth in vivo, it could persist in the infected mice for a long time, and therefore could be a potential vaccine candidate.

Branched chain amino Acids as in vitro and in vivo Anti-Oxidation Compounds

2021 ◽  
pp. 3899-3904
Author(s):  
Moath Alqaraleh ◽  
Violet Kasabri ◽  
Ibrahim Al-Majali ◽  
Nihad Al-Othman ◽  
Nihad Al-Othman ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Amino Acids ◽  
Branched Chain Amino Acids ◽  
Raw 264.7 ◽  
Raw 264.7 Cell ◽  
Branched Chain ◽  
Raw 264.7 Cell Line

Background and aims: Branched chain amino acids (BCAAs) can be tightly connected to metabolism syndrome (MetS) which can be counted as a metabolic indicator in the case of insulin resistance (IR). The aim of this study was to assess the potential role of these acids under oxidative stress. Material and Methods: the in vitro antioxidant activity of BCAAs was assessed using free radical 1, 1-diphenyl-2-picryl-hydrazyl (DPPH) scavenging assays. For further check, a qRT-PCR technique was madefor detection the extent of alterations in gene expression of antioxidative enzymes (catalase and glutathione peroxidase (Gpx)) in lipopolysaccharides (LPS(-induced macrophages RAW 264.7 cell line. Additionally, BCAAs antioxidant activity was evaluated based on plasma H2O2 levels and xanthine oxidase (XO) activity in prooxidative LPS-treated mice. Results: Different concentrations of BCAAs affected on DPPH radical scavenging activity but to lesser extent than the ascorbic acid. Besides, BCAAs obviously upregulated the gene expression levels of catalases and Gpx in LPS-modulated macrophage RAW 264.7 cell line. In vivo BCAAs significantly minimized the level of plasma H2O2 as well as the activity of XO activity under oxidative stress. Conclusion: our current findings suggest that BCAAs supplementation may potentially serve as a therapeutic target for treatment of oxidative stress occurs with atherosclerosis, IR-diabetes, MetS and tumorigenesis.

Production and utilization of amino acids by ovine placenta in vivo

1998 ◽  
Vol 274 (1) ◽  
pp. E13-E22 ◽  
Author(s):  
Misoo Chung ◽  
Cecilia Teng ◽  
Michelle Timmerman ◽  
Giacomo Meschia ◽  
Frederick C. Battaglia
Keyword(s):  
Amino Acids ◽  
Branched Chain Amino Acids ◽  
Plasma Amino Acids ◽  
Physiological Conditions ◽  
Ovine Placenta ◽  
Branched Chain ◽  
Glutamine Production

Uterine and umbilical uptakes of plasma amino acids were measured simultaneously in eighteen singleton pregnant ewes at 130 ± 1 days gestation for the purpose of establishing which amino acids are produced or used by the uteroplacenta under normal physiological conditions and at what rates. The branched-chain amino acids (BCAA) had uterine uptakes significantly greater than umbilical uptakes. Net uteroplacental BCAA utilization was 8.0 ± 2.5 μmol ⋅ kg fetus−1 ⋅ min−1( P < 0.005) and represented 42% of the total BCAA utilization by fetus plus uteroplacenta. There was placental uptake of fetal glutamate (4.2 ± 0.3 μmol ⋅ kg fetus−1 ⋅ min−1, P < 0.001) and no uterine uptake of maternal glutamate. Umbilical uptake of glutamine was ∼61% greater than uterine uptake, thus demonstrating net uteroplacental glutamine production of 2.2 ± 0.9 μmol ⋅ kg fetus−1 ⋅ min−1( P < 0.021). In conjunction with other evidence, these data indicate rapid placental metabolism of glutamate, which is in part supplied by the fetus and in part produced locally via BCAA transamination. Most of the glutamate is oxidized, and some is used to synthesize glutamine, which is delivered to the fetus. There was net uteroplacental utilization of maternal serine and umbilical uptake of glycine produced by the placenta. Maternal serine utilization and glycine umbilical uptake were virtually equal (3.14 ± 0.50 vs. 3.10 ± 0.46 μmol ⋅ kg fetus−1 ⋅ min−1). This evidence supports the conclusion that the ovine placenta converts large quantities of maternal serine into fetal glycine.

Effect of carnitine on branched-chain amino acid oxidation by liver and skeletal muscle.

1978 ◽  
Vol 234 (5) ◽  
pp. E494 ◽  
Author(s):  
H S Paul ◽  
S A Adibi
Keyword(s):  
Amino Acids ◽  
Liver Mitochondria ◽  
Branched Chain Amino Acids ◽  
Diabetic Rats ◽  
Acid Oxidation ◽  
Acyltransferase Activity ◽  
Remarkable Effect ◽  
Carnitine Acyltransferase ◽  
Branched Chain Amino Acid ◽  
Branched Chain

The effect of L-carnitine (0.5-2.0 mM) on the rates of alpha-decarboxylation of 1-14C-labeled branched-chain amino acids by gastrocnemius muscle and liver homogenates of fed rats was investigated. Carnitine increased the rate of alpha-decarboxylation of leucine (125%) and valine (28%) by muscle, but it was without effect on the oxidation of these amino acids by liver. Carnitine increased the rate of alpha-decarboxylation of alpha-ketoisocaproate by both tissues. This effect was more pronounced in muscle (130% increase) than in liver (41% increase). The activity of carnitine acyltransferase, with isovaleryl-CoA as a substrate, was 18 times higher in muscle mitochondria than in liver mitochondria. Both starvation and diabetes increased the rate of alpha-decarboxylation of leucine by muscle without having a remarkable effect on the concentration of carnitine or the activity of carnitine acyltransferase. We conclude that: a) carnitine stimulates decarboxylation of branched-chain amino acids by increasing the conversion of their ketoanalogues into carnitine esters, b) a greater carnitine acyltransferase activity in muscle than in liver may be responsible for the greater carnitine effect in muscle, c) carnitine does not appear responsible for the enhancement of leucine oxidation by muscle of starved and diabetic rats.

Transamination of branched-chain keto acids by isolated perfused rat kidney.

1978 ◽  
Vol 235 (1) ◽  
pp. E47
Author(s):  
W E Mitch ◽  
W Chan
Keyword(s):  
Amino Acids ◽  
Rat Kidney ◽  
Branched Chain Amino Acids ◽  
Keto Acid ◽  
Branched Chain Amino Acid ◽  
Keto Acids ◽  
Perfused Rat Kidney ◽  
Branched Chain ◽  
Branched Chain Keto Acids ◽  
Isolated Rat

Isolated rat kidney perfused without substrate released serine, glycine, and taurine, and substantially smaller amounts of other amino acids. When branched-chain keto acids were added, the corresponding amino acids were released at rates amounting to 15-25% of keto acid disappearance. Perfusion with 2 mM alpha-keto-isovalerate or alpha-keto-beta-methylvalerate caused an increased glucose release amounting to 18-23% of keto acid disappearance. The activity of branched-chain amino acid transferase (BATase) was significantly stimulated by perfusion with the analogue of leucine, but not by perfusion with alpha-ketoglutarate, the analogues of valine or isoleucine, or with leucine itself. These findings document that the kidney converts branched-chain keto acids in part to the corresponding amino acids and suggest that the keto analogue of leucine may be involved in the control of renal BATase activity, thereby indirectly regulating the metabolism of branched-chain amino acids.

scholarly journals Molecular Mechanisms Underlying the Positive Stringent Response of the Bacillus subtilis ilv-leu Operon, Involved in the Biosynthesis of Branched-Chain Amino Acids

2008 ◽  
Vol 190 (18) ◽  
pp. 6134-6147 ◽  
Author(s):  
Shigeo Tojo ◽  
Takenori Satomura ◽  
Kanako Kumamoto ◽  
Kazutake Hirooka ◽  
Yasutaro Fujita
Keyword(s):  
Amino Acids ◽  
Bacillus Subtilis ◽  
Transcription Initiation ◽  
Molecular Mechanisms ◽  
Stringent Response ◽  
Branched Chain Amino Acids ◽  
Base Substitution ◽  
Branched Chain

ABSTRACT Branched-chain amino acids are the most abundant amino acids in proteins. The Bacillus subtilis ilv-leu operon is involved in the biosynthesis of branched-chain amino acids. This operon exhibits a RelA-dependent positive stringent response to amino acid starvation. We investigated this positive stringent response upon lysine starvation as well as decoyinine treatment. Deletion analysis involving various lacZ fusions revealed two molecular mechanisms underlying the positive stringent response of ilv-leu, i.e., CodY-dependent and -independent mechanisms. The former is most likely triggered by the decrease in the in vivo concentration of GTP upon lysine starvation, GTP being a corepressor of the CodY protein. So, the GTP decrease derepressed ilv-leu expression through detachment of the CodY protein from its cis elements upstream of the ilv-leu promoter. By means of base substitution and in vitro transcription analyses, the latter (CodY-independent) mechanism was found to comprise the modulation of the transcription initiation frequency, which likely depends on fluctuation of the in vivo RNA polymerase substrate concentrations after stringent treatment, and to involve at least the base species of adenine at the 5′ end of the ilv-leu transcript. As discussed, this mechanism is presumably distinct from that for B. subtilis rrn operons, which involves changes in the in vivo concentration of the initiating GTP.

scholarly journals Dietary casein, egg albumin, and branched-chain amino acids attenuate phosphate-induced renal tubulointerstitial injury in rats

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Karin Shimada ◽  
Isao Matsui ◽  
Kazunori Inoue ◽  
Ayumi Matsumoto ◽  
Seiichi Yasuda ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Muscle Weakness ◽  
Branched Chain Amino Acids ◽  
Protective Effects ◽  
Egg Albumin ◽  
Branched Chain Amino Acid ◽  
Renal Tubulointerstitial Fibrosis ◽  
Dietary Casein ◽  
Branched Chain

Abstract Dietary phosphate intake is closely correlated with protein intake. However, the effects of the latter on phosphate-induced organ injuries remain uncertain. Herein, we investigated the effects of low (10.8%), moderate (23.0%), and high (35.2%) dietary casein and egg albumin administration on phosphate-induced organ injuries in rats. The moderate and high casein levels suppressed renal tubulointerstitial fibrosis and maintained mitochondrial integrity in the kidney. The serum creatinine levels were suppressed only in the high casein group. Phosphate-induced muscle weakness was also ameliorated by high dietary casein. The urinary and fecal phosphate levels in the early experiment stage showed that dietary casein did not affect phosphate absorption from the intestine. High dietary egg albumin showed similar kidney protective effects, while the egg albumin effects on muscle weakness were only marginally significant. As the plasma branched-chain amino acid levels were elevated in casein- and egg albumin-fed rats, we analyzed their effects. Dietary supplementation of 10% branched-chain amino acids suppressed phosphate-induced kidney injury and muscle weakness. Although dietary protein restriction is recommended in cases of chronic kidney disease, our findings indicate that the dietary casein, egg albumin, and branched-chain amino acid effects might be reconsidered in the era of a phosphate-enriched diet.

scholarly journals Enzymic determination of branched-chain amino acids and 2-oxoacids in rat tissues. Transfer of 2-oxoacids from skeletal muscle to liver in vivo

1980 ◽  
Vol 188 (3) ◽  
pp. 705-713 ◽  
Author(s):  
G Livesey ◽  
P Lund
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Bacillus Subtilis ◽  
Branched Chain Amino Acids ◽  
Rat Tissues ◽  
Arterial Blood ◽  
Branched Chain ◽  
Arteriovenous Difference

1. A procedure is described for the purification of leucine dehydrogenase (EC 1.4.1.9) from Bacillus subtilis. 2. The preparation is suitable for the quantitative assay of branched-chain amino acids and their 2-oxoacid analogues. 3. The content of total branched-chain 2-oxoacids in freeze-clamped liver, kidney, heart or mammary gland of fed rats is less than 5 nmol/g fresh wt. Higher amounts are present in skeletal muscle and arterial blood (25 +/- 4 nmol per g fresh wt., and 33 +/- 6 nmol per ml respectively; means +/- S.D. of 3 and 11 animals respectively). The values are not significantly affected by starvation for 24 h. 4. Arteriovenous difference measurements show that considerable amounts of branched-chain 2-oxoacids are released by skeletal muscle into the circulation and similar amounts are removed by the liver (about 1 mmol/24 h in a 400 g rat).

scholarly journals Amino acid infusion increases the sensitivity of muscle protein synthesis in vivo to insulin. Effect of branched-chain amino acids

1988 ◽  
Vol 254 (2) ◽  
pp. 579-584 ◽  
Author(s):  
P J Garlick ◽  
I Grant
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Branched Chain Amino Acids ◽  
Acid Infusion ◽  
Amino Acid Infusion ◽  
Branched Chain

Rates of muscle protein synthesis were measured in vivo in tissues of post-absorptive young rats that were given intravenous infusions of various combinations of insulin and amino acids. In the absence of amino acid infusion, there was a steady rise in muscle protein synthesis with plasma insulin concentration up to 158 mu units/ml, but when a complete amino acids mixtures was included maximal rates were obtained at 20 mu units/ml. The effect of the complete mixture could be reproduced by a mixture of essential amino acids or of branched-chain amino acids, but not by a non-essential mixture, alanine, methionine or glutamine. It is concluded that amino acids, particularly the branched-chain ones, increase the sensitivity of muscle protein synthesis to insulin.

scholarly journals Mechanism of De Novo Branched-Chain Amino Acid Synthesis as an Alternative Electron Sink in Hypoxic Aspergillus nidulans Cells

2010 ◽  
Vol 76 (5) ◽  
pp. 1507-1515 ◽  
Author(s):  
Motoyuki Shimizu ◽  
Tatsuya Fujii ◽  
Shunsuke Masuo ◽  
Naoki Takaya
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Aspergillus Nidulans ◽  
De Novo ◽  
Acid Synthesis ◽  
Branched Chain Amino Acids ◽  
Amino Acid Synthesis ◽  
Lactate Dehydrogenase Activity ◽  
Branched Chain Amino Acid ◽  
Branched Chain

ABSTRACT Although branched-chain amino acids are synthesized as building blocks of proteins, we found that the fungus Aspergillus nidulans excretes them into the culture medium under hypoxia. The transcription of predicted genes for synthesizing branched-chain amino acids was upregulated by hypoxia. A knockout strain of the gene encoding the large subunit of acetohydroxy acid synthase (AHAS), which catalyzes the initial reaction of the synthesis, required branched-chain amino acids for growth and excreted very little of them. Pyruvate, a substrate for AHAS, increased the amount of hypoxic excretion in the wild-type strain. These results indicated that the fungus responds to hypoxia by synthesizing branched-chain amino acids via a de novo mechanism. We also found that the small subunit of AHAS regulated hypoxic branched-chain amino acid production as well as cellular AHAS activity. The AHAS knockout resulted in higher ratios of NADH/NAD+ and NADPH/NADP+ under hypoxia, indicating that the branched-chain amino acid synthesis contributed to NAD+ and NADP+ regeneration. The production of branched-chain amino acids and the hypoxic induction of involved genes were partly repressed in the presence of glucose, where cells produced ethanol and lactate and increased levels of lactate dehydrogenase activity. These indicated that hypoxic branched-chain amino acid synthesis is a unique alternative mechanism that functions in the absence of glucose-to-ethanol/lactate fermentation and oxygen respiration.

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