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.

scholarly journals Acetolactate synthase regulatory subunits play divergent and overlapping roles in branched-chain amino acid synthesis and Arabidopsis development

2017 ◽  
Vol 17 (1) ◽  
Author(s):  
Mohammad H. Dezfulian ◽  
Curtis Foreman ◽  
Espanta Jalili ◽  
Mrinal Pal ◽  
Rajdeep K. Dhaliwal ◽  
...  
Keyword(s):  
Amino Acid ◽  
Acetolactate Synthase ◽  
Acid Synthesis ◽  
Amino Acid Synthesis ◽  
Regulatory Subunits ◽  
Branched Chain Amino Acid ◽  
Branched Chain

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 Repression of branched-chain amino acid synthesis in Staphylococcus aureus is mediated by isoleucine via CodY, and by a leucine-rich attenuator peptide

PLoS Genetics ◽  
2018 ◽  
Vol 14 (1) ◽  
pp. e1007159 ◽  
Author(s):  
Julienne C. Kaiser ◽  
Alyssa N. King ◽  
Jason C. Grigg ◽  
Jessica R. Sheldon ◽  
David R. Edgell ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Amino Acid ◽  
Acid Synthesis ◽  
Amino Acid Synthesis ◽  
Branched Chain Amino Acid ◽  
Branched Chain

scholarly journals RESISTÊNCIA DE PLANTAS DANINHAS: SELEÇÃO OU INDUÇÃO À MUTAÇÃO PELOS HERBICIDAS INIBIDORES DE ACETOLACTATO

2002 ◽  
Vol 12 ◽  
Author(s):  
RIBAS ANTONIO VIDAL ◽  
LARISSA MACEDO WINKLER
Keyword(s):  
Amino Acids ◽  
Arabidopsis Thaliana ◽  
Amino Acid ◽  
Dna Replication ◽  
Branched Chain Amino Acids ◽  
Amino Acid Synthesis ◽  
Replication Errors ◽  
Resistance To Herbicides ◽  
Branched Chain ◽  
Weed Resistance

A resistência de plantas daninhas aos herbicidas, principalmente os inibidores da síntese de aminoácidos ramificados (isoleucina, leucina e valina), está se propagando no Brasil. A literatura propõem que a resistência aos herbicidas ocorre devido à seleção de indivíduos mutantes já presentes na comunidade vegetal aspergida pelo herbicida. Contudo, durante a replicação do DNA ocorrem erros que são corrigidos por diversas proteínas. Já foi identificada a composição de aminoácidos das proteínas do grupo MutS, responsáveis pela correção de erros replicativos em Arabidopsis thaliana. Com base na elevada composição dos aminoácidos ramificados nas proteínas do grupo MutS, este trabalho questiona se a ausência desses aminoácidos em momentos críticos da replicação do DNA pode estar prejudicando a correção dos erros do DNA das plantas daninhas. Comparações são feitas entre possíveis efeitos de inibidores de acetolactato sintase (ALS) e de enol-piruvil-shiquimatofosfato- sintase (EPSPS). Com base nessas informações sugere-se que herbicidas inibidores da síntese de aminoácidos ramificados podem propiciar o aparecimento de mais indivíduos mutantes resistentes aos mesmos. WEED RESISTANCE: SELECTION OR INDUCTION TO MUTATION BY INHIBITORS OF ACETO LACTATE SYNTASE HERBICIDES Abstract The weed resistance to herbicides is widely spread in Brazil, mainly for the compounds inhibitors of the synthesis of branched-chain amino acids, isoleucine, leucine and valine. The literature proposes that the resistance to herbicides appears as result of selection of mutant individual plants existent in the weed flora prior to herbicide application. However, during DNA replication occur replication errors, that are corrected by several proteins. It is already known the amino acid composition of the proteins from the group MutS, responsible for the correction of replication errors in Arabidopsis thaliana. Based on the high composition of branched-chain amino acids on the group MutS proteins, in this work it is hypothesized that the absence of these amino acids on critical moments of the DNA replication can be interfering on the correction of the DNA replication errors in weeds. Possible effect of aceto lactate syntase (ALS) and enolpyruvil- shiquimato-phosphate syntase (EPSPS) inhibithing herbicides are compared. This review suggests that herbicides inhibitor of branched chain amino acid synthesis can trigger the appearance of more mutant weeds resistant to the herbicides when sprayed by these compounds.

scholarly journals Eucalyptus ESTs associated with resistance to herbicide inhibitors of aromatic and branched-chain amino acid synthesis

2005 ◽  
Vol 28 (3 suppl) ◽  
pp. 575-581
Author(s):  
Edivaldo Domingues Velini ◽  
Maria Lúcia Bueno Trindade ◽  
Elza Alves ◽  
Ana Catarina Catâneo ◽  
Celso Luis Marino ◽  
...  
Keyword(s):  
Amino Acid ◽  
Acid Synthesis ◽  
Amino Acid Synthesis ◽  
Branched Chain Amino Acid ◽  
Branched Chain

Effect of Infused Branched-Chain Amino Acids on Muscle and Whole-Body Amino Acid Metabolism in Man

1990 ◽  
Vol 79 (5) ◽  
pp. 457-466 ◽  
Author(s):  
Rita J. Louard ◽  
Eugene J. Barrett ◽  
Robert A. Gelfand
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Branched Chain Amino Acids ◽  
Whole Body ◽  
Acid Infusion ◽  
Amino Acid Infusion ◽  
Branched Chain Amino Acid ◽  
Branched Chain

1. Using the forearm balance method, together with systemic infusions of l-[ring-2,6-3H]phenylalanine and l-[1-14C]leucine, we examined the effects of infused branched-chain amino acids on whole-body and skeletal muscle amino acid kinetics in 10 postabsorptive normal subjects; 10 control subjects received only saline. 2. Infusion of branched-chain amino acids caused a four-fold rise in arterial branched-chain amino acid levels and a two-fold rise in branched-chain keto acids; significant declines were observed in circulating levels of most other amino acids, including phenylalanine, which fell by 34%. Plasma insulin levels were unchanged from basal levels (8 ± 1 μ-units/ml). 3. Whole-body phenylalanine flux, an index of proteolysis, was significantly suppressed by branched-chain amino acid infusion (P < 0.002), and forearm phenylalanine production was also inhibited (P < 0.03). With branched-chain amino acid infusion total leucine flux rose, with marked increments in both oxidative and non-oxidative leucine disposal (P < 0.001). Proteolysis, as measured by endogenous leucine production, showed a modest 12% decrease, although this was not significant when compared with saline controls. The net forearm balance of leucine and other branched-chain amino acids changed from a basal net output to a marked net uptake (P < 0.001) during branched-chain amino acid infusion, with significant stimulation of local leucine disposal. Despite the rise in whole-body non-oxidative leucine disposal, and in forearm leucine uptake and disposal, forearm phenylalanine disposal, an index of muscle protein synthesis, was not stimulated by infusion of branched-chain amino acids. 4. The results suggest that in normal man branched-chain amino acid infusion suppresses skeletal muscle proteolysis independently of any rise of plasma insulin. Muscle branched-chain amino acid uptake rose dramatically in the absence of any apparent increase in muscle protein synthesis, as measured by phenylalanine disposal, or in branched-chain keto acid release. Thus, an increase in muscle branched-chain amino acid concentrations and/ or local branched-chain amino acid oxidation must account for the increased disposal of branched-chain amino acids.

A Comparison of the Effects of Intravenous Infusion of Individual Branched-Chain Amino Acids on Blood Amino Acid Levels in Man

1981 ◽  
Vol 60 (1) ◽  
pp. 95-100 ◽  
Author(s):  
S. Eriksson ◽  
L. Hagenfeldt ◽  
J. Wahren
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Intravenous Infusion ◽  
Serum Insulin ◽  
Aromatic Amino Acids ◽  
Branched Chain Amino Acids ◽  
Blood Concentrations ◽  
Branched Chain Amino Acid ◽  
Amino Acid Levels ◽  
Branched Chain

1., Intravenous infusions of l-valine (600 μmol/min), l-isoleucine (150 μmol/min), l-leucine (300 μmol/min) and a mixture of the three branched-chain amino acids (70% l-leucine, 20% l-valine, 10% l-isoleucine; 270 μmol/min) were given to four groups of healthy volunteer subjects. Whole-blood concentrations of amino acids and glucose and serum insulin were measured before and during the infusions. 2. Valine and isoleucine infusions resulted in twelve- and six-fold increases in the respective amino acid. During valine infusion, tyrosine was the only amino acid for which a decrease in concentration was seen (25%, P < 0.05). With isoleucine administration, no significant changes were found. In contrast, leucine infusion (during which the leucine concentration rose about sixfold) was accompanied by significant decreases in tyrosine (35%), phenylalanine (35%), methionine (50%), valine (40%) and isoleucine (55%). The arterial glucose concentration fell slightly (5%) and the insulin concentration increased 20% during leucine infusion. 3. Infusion of the mixture of the three branched-chain amino acids resulted in marked decreases in tyrosine (50%), phenylalanine (50%) and methionine (35%). The decreased amino acid levels remained low for 2 h after the end of the infusion. 4. The present findings demonstrate that intravenous infusion of leucine (not infusion of valine or isoleucine) results in marked reductions in the concentrations of the aromatic amino acids and methionine. Infusion of a mixture of the three branched-chain amino acids gives results similar to those obtained with leucine infusion alone. Thus a mixed branched-chain amino acid solution with leucine as its main constituent seems to be the best alternative in the treatment of patients with hepatic cirrhosis and encephalopathy.

Nitrogen in dietary glutamate is utilized exclusively for the synthesis of amino acids in the rat intestine

2013 ◽  
Vol 304 (1) ◽  
pp. E100-E108 ◽  
Author(s):  
Hidehiro Nakamura ◽  
Yasuko Kawamata ◽  
Tomomi Kuwahara ◽  
Kunio Torii ◽  
Ryosei Sakai
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Portal Vein ◽  
Acid Synthesis ◽  
Male Rats ◽  
Isotopic Enrichment ◽  
Amino Acid Synthesis ◽  
Quantitative Evidence ◽  
Branched Chain ◽  
Net Release

Although previous studies have shown that virtually the entire carbon skeleton of dietary glutamate (glutamate-C) is metabolized in the gut for energy production and amino acid synthesis, little is known regarding the fate of dietary glutamate nitrogen (glutamate-N). In this study, we hypothesized that dietary glutamate-N is an effective nitrogen source for amino acid synthesis and investigated the fate of dietary glutamate-N using [15N]glutamate. Fischer male rats were given hourly meals containing [U-13C]- or [15N]glutamate. The concentration and isotopic enrichment of several amino acids were measured after 0–9 h of feeding, and the net release of each amino acid into the portal vein was calculated. Most of the dietary glutamate-C was metabolized into CO2, lactate, or alanine (56, 13, and 12% of the dietary input, respectively) in the portal drained viscera (PDV). Most of the glutamate-N was utilized for the synthesis of other amino acids such as alanine and citrulline (75 and 3% of dietary input, respectively) in the PDV, and only minor amounts were released into the portal vein in the form of ammonia and glutamate (2 and 3% of the dietary input, respectively). Substantial incorporation of 15N into systemic amino acids such as alanine, glutamine, and proline, amino acids of the urea cycle, and branched-chain amino acids was also evident. These results provide quantitative evidence that dietary glutamate-N distributes extensively to amino acids synthesized in the PDV and, consequently, to circulating amino acids.

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