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1.
Commun Biol ; 6(1): 118, 2023 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-36709236

RESUMO

Although Clostridium novyi-NT is an anti-cancer bacterial therapeutic which germinates within hypoxic tumors to kill cancer cells, the actual germination triggers for C. novyi-NT are still unknown. In this study, we screen candidate germinants using combinatorial experimental designs and discover by serendipity that D-valine is a potent germinant, inducing 50% spore germination at 4.2 mM concentration. Further investigation revealed that five D-valine analogs are also germinants and four of these analogs are enantiomeric pairs. This stereoflexible effect of L- and D-amino acids shows that spore germination is a complex process where enantiomeric interactions can be confounders. This study also identifies L-cysteine as a germinant, and hypoxanthine and inosine as co-germinants. Several other amino acids promote (L-valine, L-histidine, L-threonine and L-alanine) or inhibit (L-arginine, L-glycine, L-lysine, L-tryptophan) germination in an interaction-dependent manner. D-alanine inhibits all germination, even in complex growth media. This work lays the foundation for improving the germination efficacy of C. novyi-NT spores in tumors.


Assuntos
Esporos Bacterianos , Valina , Valina/metabolismo , Valina/farmacologia , Esporos Bacterianos/metabolismo , Aminoácidos/metabolismo , Alanina , Esporos/metabolismo
2.
J Chem Inf Model ; 63(1): 197-207, 2023 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-36512416

RESUMO

One of the most challenging aspects in the molecular simulation of proteins is the study of slowly relaxing processes, such as loop rearrangements or ligands that adopt different conformations in the binding site. State-of-the-art methods used to calculate binding free energies rely on performing several short simulations (lambda steps), in which the ligand is slowly transformed into the endstates of interest. This makes capturing the slowly relaxing processes even more difficult, as they would need to be observed in all of the lambda steps. One attractive alternative is the use of a reference state capable of sampling all of the endstates of interest in a single simulation. However, the energy barriers between the states can be too high to overcome, thus hindering the sampling of all of the relevant conformations. Accelerated enveloping distribution sampling (AEDS) is a recently developed reference state technique that circumvents the high-energy-barrier challenge by adding a boosting potential that flattens the energy landscape without distorting the energy minima. In the present work, we apply AEDS to the well-studied benchmark system T4 lysozyme L99A. The T4 lysozyme L99A mutant contains a hydrophobic pocket in which there is a valine (valine 111), whose conformation influences the binding efficiencies of the different ligands. Incorrectly sampling the dihedral angle can lead to errors in predicted binding free energies of up to 16 kJ mol-1. This protein constitutes an ideal scenario to showcase the advantages and challenges when using AEDS in the presence of slow relaxing processes. We show that AEDS is able to successfully sample the relevant degrees of freedom, providing accurate binding free energies, without the need of previous information of the system in the form of collective variables. Additionally, we showcase the capabilities of AEDS to efficiently screen a set of ligands. These results represent a promising first step toward the development of free-energy methods that can respond to more intricate molecular events.


Assuntos
Muramidase , Proteínas , Muramidase/química , Proteínas/química , Sítios de Ligação , Simulação por Computador , Valina/metabolismo , Simulação de Dinâmica Molecular , Termodinâmica , Ligantes , Ligação Proteica
3.
Poult Sci ; 101(12): 102196, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36272234

RESUMO

The objective of this experiment was to compare the slaughter and cecectomy methods to determine amino acid (AA) digestibility of corn and soybean meal and their additivity in a corn-soybean meal diet. A completely randomized design was adopted to determine endogenous AA losses (EAAL) and AA digestibility in each of corn, soybean meal, and a corn-soybean meal diet using either slaughter or cecectomy methods. Each treatment contained 6 replicates with 3 chickens per replicate. The endogenous loss (EL) of histidine and glycine was lower and the EL of methionine and phenylalanine was greater when determined by slaughter vs. cecectomy (P < 0.05). The EL of arginine, isoleucine, leucine, lysine, methionine, phenylalanine, valine, alanine, aspartic acid, glutamic acid, and serine determined by slaughter were 1.2 to 3.2 times of those from cecectomy. The standard error (SE) of EL of 14 AA (excluding histidine and glycine) obtained by slaughter method was 2.1 to 9.6 times of those by cecectomy method. The apparent and standardized digestibility was not affected by methods for most AA except apparent digestibility of methionine, phenylalanine and glycine, and standardized digestibility of glycine in corn. The apparent and standardized digestibility of most AA except apparent digestibility of glycine and standardized digestibility of lysine, cysteine and glycine were less for slaughter versus cecectomy methods in soybean meal (P < 0.05). Using slaughter method resulted in reduced apparent digestibility of 15 AA (except glycine) and reduced standardized digestibility of 7 AA (arginine, isoleucine, leucine, valine, aspartic acid, glutamic acid, and proline) relative to cecectomy method (P < 0.05), but the standardized digestibility of glycine was greater when determined by slaughter vs. cecectomy methods in corn-soybean meal diet (P < 0.05). The mean value of SE of 16 AA digestibility in slaughter method was 2.9 times of that by cecectomy method. The apparent digestibility of 2 and 9 of 16 AA and the standardized digestibility of 15 and 7 of 16 AA were additive when using slaughter and cecectomy determinations, respectively. In conclusion, compared to the slaughter method, cecectomy method had less SE and EAAL but greater apparent digestibility of methionine and phenylalanine in corn, and the apparent digestibility of 15 AA (except glycine) in soybean meal and corn-soybean meal diet. Additivity in apparent and standardized AA digestibility was more inconsistent when determined with slaughter vs. cecectomy methods. These findings suggest that the cecectomy method is more suitable than the slaughter method to determine the digestibility of AA.


Assuntos
Aminoácidos , Galinhas , Animais , Galinhas/metabolismo , Aminoácidos/metabolismo , Fenômenos Fisiológicos da Nutrição Animal , Digestão , Ração Animal/análise , Plumas , Leucina/metabolismo , Isoleucina/metabolismo , Lisina/metabolismo , Ácido Glutâmico , Ácido Aspártico/metabolismo , Histidina/metabolismo , Dieta/veterinária , Zea mays/química , Soja/química , Glicina/metabolismo , Metionina/metabolismo , Fenilalanina/metabolismo , Valina/metabolismo , Arginina/metabolismo , Íleo/metabolismo
4.
Nutrients ; 14(19)2022 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-36235779

RESUMO

Cocoa constitutes one of the richest sources of dietary flavonoids with demonstrated anti-diabetic potential. However, the metabolic impact of cocoa intake in a diabetic context remains unexplored. In this study, metabolomics tools have been used to investigate the potential metabolic changes induced by cocoa in type 2 diabetes (T2D). To this end, male Zucker diabetic fatty rats were fed on standard (ZDF) or 10% cocoa-rich diet (ZDF-C) from week 10 to 20 of life. Cocoa supplementation clearly decreased serum glucose levels, improved glucose metabolism and produced significant changes in the urine metabolome of ZDF animals. Fourteen differential urinary metabolites were identified, with eight of them significantly modified by cocoa. An analysis of pathways revealed that butanoate metabolism and the synthesis and degradation of branched-chain amino acids and ketone bodies are involved in the beneficial impact of cocoa on diabetes. Moreover, correlation analysis indicated major associations between some of these urine metabolites (mainly valine, leucine, and isoleucine) and body weight, glycemia, insulin sensitivity, and glycated hemoglobin levels. Overall, this untargeted metabolomics approach provides a clear metabolic fingerprint associated to chronic cocoa intake that can be used as a marker for the improvement of glucose homeostasis in a diabetic context.


Assuntos
Cacau , Diabetes Mellitus Experimental , Diabetes Mellitus Tipo 2 , Aminoácidos de Cadeia Ramificada/metabolismo , Animais , Glicemia/metabolismo , Cacau/química , Flavonoides/metabolismo , Isoleucina , Corpos Cetônicos/metabolismo , Leucina/metabolismo , Masculino , Metabolômica , Espectroscopia de Prótons por Ressonância Magnética , Ratos , Ratos Zucker , Valina/metabolismo
5.
Eur J Neurol ; 29(11): 3229-3242, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36200804

RESUMO

BACKGROUND AND PURPOSE: HIBCH and ECHS1 genes encode two enzymes implicated in the critical steps of valine catabolism, 3-hydroxyisobutyryl-coenzyme A (CoA) hydrolase (HIBCH) and short-chainenoyl-CoA hydratase (ECHS1), respectively. HIBCH deficiency (HIBCHD) and ECHS1 deficiency (ECHS1D) generate rare metabolic dysfunctions, often revealed by neurological symptoms. The aim of this study was to describe movement disorders spectrum in patients with pathogenic variants in ECHS1 and HIBC. METHODS: We reviewed a series of 18 patients (HIBCHD: 5; ECHS1D: 13) as well as 105 patients from the literature. We analysed the detailed phenotype of HIBCHD (38 patients) and ECHS1D (85 patients), focusing on MDs. RESULTS: The two diseases have a very similar neurological phenotype, with an early onset before 10 years of age for three clinical presentations: neonatal onset, Leigh-like syndrome (progressive onset or acute neurological decompensation), and isolated paroxysmal dyskinesia. Permanent or paroxysmal MDs were recorded in 61% of HIBCHD patients and 72% of ECHS1D patients. Patients had a variable combination of either isolated or combined MD, and dystonia was the main MD. These continuous MDs included dystonia, chorea, parkinsonism, athetosis, myoclonus, tremors, and abnormal eye movements. Patients with paroxysmal dyskinesia (HIBCHD: 4; ECHS1D: 9) usually had pure paroxysmal dystonia with normal clinical examination and no major impairment in psychomotor development. No correlation could be identified between clinical pattern (especially MD) and genetic pathogenic variants. CONCLUSIONS: Movement disorders, including abnormal ocular movements, are a hallmark of HIBCHD and ECHS1D. MDs are not uniform; dystonia is the most frequent, and various types of MD are combined in single patient.


Assuntos
Coreia , Distonia , Distúrbios Distônicos , Enoil-CoA Hidratase/metabolismo , Doença de Leigh , Transtornos dos Movimentos , Anormalidades Múltiplas , Erros Inatos do Metabolismo dos Aminoácidos , Coenzima A , Distúrbios Distônicos/genética , Humanos , Doença de Leigh/diagnóstico , Doença de Leigh/genética , Transtornos dos Movimentos/genética , Tioléster Hidrolases/deficiência , Valina/metabolismo
6.
Amino Acids ; 54(11): 1491-1504, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36083345

RESUMO

Dietary supplementation with branched-chain amino acids (BCAAs) to lactating sows has been reported to enhance their milk production, but the underlying mechanisms remain largely unknown. This study was conducted with porcine mammary epithelial cells (PMECs) to test the hypothesis that individual BCAAs or their mixture stimulates protein synthesis and inhibit proteolysis in PMECs. Cells were cultured at 37 °C in customized Dulbecco's modified Eagle medium containing 5 mmol/L D-glucose, 1 mmol/L L-phenylalanine, L-[ring-2,4-3H]phenylalanine, 0.1 (control), 0.25, 0.5, 1, or 2 mmol/L L-leucine, L-isoleucine or L-valine or an equimolar mixture of the three BCAAs. The culture medium also contained physiological concentrations of other amino acids found in the plasma of lactating sows. Proliferation, protein synthesis, proteolysis, ß-casein production, the mechanistic target of rapamycin (mTOR) signaling, and the ubiquitin-proteasome pathway were determined for PMECs. Cell proliferation and abundances of phosphorylated mTOR, eukaryotic translation initiation factor 4E-binding protein 1, and ribosomal protein S6 kinase ß-1 proteins increased (P < 0.05), but abundances of ubiquitinated protein and 20S proteasome decreased (P < 0.05) when extracellular concentrations of L-leucine, L-isoleucine, L-valine, or an equimolar mixture of BCAAs were increased from 0.1 to 2 mmol/L. Compared with the control, 0.25, 0.5, 1 or 2 mmol/L BCAAs enhanced (P < 0.01) protein (including ß-casein) synthesis, while decreasing (P < 0.05) proteolysis in PMECs in a dose-dependent manner. Collectively, our results indicate that physiological concentrations of BCAAs regulate protein turnover in mammary epithelial cells to favor net protein synthesis through stimulating the mTOR signaling pathway and inhibiting the ubiquitin-proteasome pathway.


Assuntos
Aminoácidos de Cadeia Ramificada , Glândulas Mamárias Animais , Suínos , Feminino , Animais , Aminoácidos de Cadeia Ramificada/metabolismo , Proteólise , Leucina/farmacologia , Leucina/metabolismo , Caseínas , Isoleucina/metabolismo , Lactação , Complexo de Endopeptidases do Proteassoma/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Células Epiteliais/metabolismo , Valina/metabolismo , Ubiquitina/metabolismo
7.
J Agric Food Chem ; 70(32): 9898-9907, 2022 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-35916279

RESUMO

Valine, a kind of branched-chain amino acid, plays a regulatory role beyond that of a building block in milk protein synthesis. However, the underlying molecular mechanism through which valine stimulates ß-casein synthesis has not been clarified. Therefore, our study aimed to evaluate the effect of valine on ß-casein synthesis and shed light into the molecular mechanism using an in vitro model. Results showed that valine supplementation significantly increased ß-casein synthesis in bovine mammary epithelial cells (BMECs). Meanwhile, the supplementation of valine resulted in high levels of branched-chain aminotransferase transaminase 2 (BCAT2), TCA-cycle intermediate metabolites, and ATP, AMP-activated protein kinase (AMPK) inhibition, and mammalian target of rapamycin (mTOR) activation. Furthermore, the inhibition of BCAT2 decreased the ß-casein synthesis and downregulated the AMPK-mTOR pathway, with similar results observed for AMPK activation. Together, the present data indicate that valine promotes the synthesis of ß-casein by affecting the AMPK-mTOR signaling axis and that BCAT2-mediated valine catabolism is the key target.


Assuntos
Proteínas Quinases Ativadas por AMP , Caseínas , Proteínas Quinases Ativadas por AMP/genética , Proteínas Quinases Ativadas por AMP/metabolismo , Animais , Caseínas/metabolismo , Bovinos , Células Epiteliais/metabolismo , Mamíferos/metabolismo , Glândulas Mamárias Animais/metabolismo , Fosforilação , Serina-Treonina Quinases TOR/genética , Serina-Treonina Quinases TOR/metabolismo , Transaminases/metabolismo , Valina/metabolismo , Valina/farmacologia
8.
Toxins (Basel) ; 14(7)2022 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-35878230

RESUMO

It is widely accepted that eutrophication has played an important role in the formation of harmful cyanobacterial blooms in recent decades, which impacts water quality and ecological environment and causes huge economic losses. Algicidal bacteria have a promising application prospect in controlling cyanobacterial blooms in aquaculture water. Here, the process of the algicidal bacterium Brevibacillus laterosporus strain Bl-zj acting on Microcystis aeruginosa was explored using transcriptome analysis to elucidate the algicidal mechanism. The results of the co-culture of bacterium and alga showed a strong alga-lysing effect of B. laterosporus against M. aeruginosa with an extreme morphology deformation of the algal cells. A total of 2744 differentially expressed genes of B. laterosporus were identified, which were mainly involved in the metabolism of amino acid, carbohydrate, and lipid. In the co-cultured group, the expression of genes mainly enriched in valine, leucine and isoleucine degradation, and fatty acid degradation were significantly increased. However, the expression of the genes related to ribosome were mainly inhibited. Transcriptome analysis showed that B. laterosporus obtained ATP and energy by the degradation of valine, leucine, isoleucine, and fatty acids, and destroyed algal cells by efflux pump transporters, secretion of hydrolytic enzymes, antibiotics, proteases, and other secondary metabolites, resulting in algal death and achieving the algicidal effect.


Assuntos
Bacillus , Microcystis , Bacillus/metabolismo , Brevibacillus , Perfilação da Expressão Gênica , Proliferação Nociva de Algas , Isoleucina/metabolismo , Isoleucina/farmacologia , Leucina/metabolismo , Redes e Vias Metabólicas , Microcystis/metabolismo , Valina/metabolismo , Valina/farmacologia
9.
Am J Med Genet A ; 188(10): 2908-2919, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35856138

RESUMO

ECHS1 gene encodes a mitochondrial enzyme, short-chain enoyl-CoA hydratase (SCEH). SCEH is involved in fatty acid oxidation ([Sharpe and McKenzie (2018); Mitochondrial fatty acid oxidation disorders associated with short-chain enoyl-CoA hydratase (ECHS1) deficiency, 7: 46]) and valine catabolism ([Fong and Schulz (1977); Purification and properties of pig heart crotonase and the presence of short chain and long chain enoyl coenzyme A hydratases in pig and guinea pig tissues, 252: 542-547]; [Wanders et al. (2012); Enzymology of the branched-chain amino acid oxidation disorders: The valine pathway, 35: 5-12]), and the dysfunction of SCEH leads to a severe Leigh or Leigh-like Syndrome phenotype in patients ([Haack et al. (2015); Deficiency of ECHS1 causes mitochondrial encephalopathy with cardiac involvement, 2: 492-509]; [Peters et al. (2014); ECHS1 mutations in Leigh disease: A new inborn error of metabolism affecting valine metabolism, 137: 2903-2908]; [Sakai et al. (2015); ECHS1 mutations cause combined respiratory chain deficiency resulting in Leigh syndrome, 36: 232-239]; [Tetreault et al. (2015); Whole-exome sequencing identifies novel ECHS1 mutations in Leigh, 134: 981-991]). This study aims to further describe the ECHS1 deficiency phenotype using medical history questionnaires and standardized tools assessing quality of life and adaptive skills. Our findings in this largest sample of ECHS1 patients in literature to date (n = 13) illustrate a severely disabling condition causing severe developmental delays (n = 11), regression (n = 10), dystonia/hypotonia and movement disorders (n = 13), commonly with symptom onset in infancy (n = 10), classical MRI findings involving the basal ganglia (n = 11), and variability in biochemical profile. Congruent with the medical history, our patients had significantly low composite and domain scores on Vineland Adaptive Behavior Scales, Third Edition. We believe there is an increasing need for better understanding of ECHS1 deficiency with an aim to support the development of transformative genetic-based therapies, driven by the unmet need for therapies for patients with this genetic disease.


Assuntos
Doença de Leigh , Qualidade de Vida , Animais , Cardiomiopatias , Enoil-CoA Hidratase , Ácidos Graxos , Cobaias , Doença de Leigh/genética , Erros Inatos do Metabolismo Lipídico , Miopatias Mitocondriais , Proteína Mitocondrial Trifuncional/deficiência , Doenças do Sistema Nervoso , Fenótipo , Rabdomiólise , Valina/metabolismo
10.
Theor Appl Genet ; 135(8): 2817-2831, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35779128

RESUMO

KEY MESSAGE: An alanine to valine mutation of glutamyl-tRNA reductase's 510th amino acid improves 5-aminolevulinic acid synthesis in rice. 5-aminolevulinic acid (ALA) is the common precursor of all tetrapyrroles and plays an important role in plant growth regulation. ALA is synthesized from glutamate, catalyzed by glutamyl-tRNA synthetase (GluRS), glutamyl-tRNA reductase (GluTR), and glutamate-1-semialdehyde aminotransferase (GSAT). In Arabidopsis, ALA synthesis is the rate-limiting step in tetrapyrrole production via GluTR post-translational regulations. In rice, mutations of GluTR and GSAT homologs are known to confer chlorophyll deficiency phenotypes; however, the enzymatic activity of rice GluRS, GluTR, and GSAT and the post-translational regulation of rice GluTR have not been investigated experimentally. We have demonstrated that a suppressor mutation in rice partially reverts the xantha trait. In the present study, we first determine that the suppressor mutation results from a G → A nucleotide substitution of OsGluTR (and an A → V change of its 510th amino acid). Protein homology modeling and molecular docking show that the OsGluTRA510V mutation increases its substrate binding. We then demonstrate that the OsGluTRA510V mutation increases ALA synthesis in Escherichia coli without affecting its interaction with OsFLU. We further explore homologous genes encoding GluTR across 193 plant species and find that the amino acid (A) is 100% conserved at the position, suggesting its critical role in GluTR. Thus, we demonstrate that the gain-of-function OsGluTRA510V mutation underlies suppression of the xantha trait, experimentally proves the enzymatic activity of rice GluRS, GluTR, and GSAT in ALA synthesis, and uncovers conservation of the alanine corresponding to the 510th amino acid of OsGluTR across plant species.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Oryza , Alanina/genética , Alanina/metabolismo , Aldeído Oxirredutases , Ácido Aminolevulínico/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Simulação de Acoplamento Molecular , Mutação , Oryza/genética , Oryza/metabolismo , Valina/genética , Valina/metabolismo
11.
ISME J ; 16(11): 2491-2502, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35896730

RESUMO

The mammalian intestine harbors heterogeneous distribution of microbes among which specific taxa (e.g. Lactobacillus) dominate across mammals. Deterministic factors such as nutrient availability and utilization may affect microbial distributions. Due to physiological complexity, mechanisms linking nutrient utilization and the dominance of key taxa remain unclear. Lactobacillus amylovorus is a predominant species in the small intestine of pigs. Employing a pig model, we found that the small intestine was dominated by Lactobacillus and particularly L. amylovorus, and enriched with peptide-bound amino acids (PBAAs), all of which were further boosted after a peptide-rich diet. To investigate the bacterial growth dominance mechanism, a representative strain L. amylovorus S1 was isolated from the small intestine and anaerobically cultured in media with free amino acids or peptides as sole nitrogen sources. L. amylovorus S1 grew preferentially with peptide-rich rather than amino acid-rich substrates, as reflected by enhanced growth and PBAA utilization, and peptide transporter upregulations. Utilization of free amino acids (e.g. methionine, valine, lysine) and expressions of transporters and metabolic enzymes were enhanced simultaneously in peptide-rich substrate. Additionally, lactate was elevated in peptide-rich substrates while acetate in amino acid-rich substrates, indicating distinct metabolic patterns depending on substrate forms. These results suggest that an increased capability of utilizing PBAAs contributes to the dominance of L. amylovorus, indicating amino acid utilization as a deterministic factor affecting intestinal microbial distribution. These findings may provide new insights into the microbe-gut nutrition interplay and guidelines for dietary manipulations toward gut health especially small intestine health.


Assuntos
Aminoácidos , Lactobacillus acidophilus , Aminoácidos/metabolismo , Animais , Lactatos/metabolismo , Lactobacillus , Lactobacillus acidophilus/metabolismo , Lisina/metabolismo , Mamíferos , Metionina/metabolismo , Nitrogênio/metabolismo , Suínos , Valina/metabolismo
12.
Biochim Biophys Acta Bioenerg ; 1863(7): 148580, 2022 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-35654167

RESUMO

Photosystem (PS) II is prone to photodamage both as a direct consequence of light, and indirectly by producing reactive oxygen species. Engineering high-light tolerance in cyanobacteria with minimal impact on PSII function is desirable in synthetic biology. IsiA, a CP43 homolog found exclusively in cyanobacteria, can dissipate excess light energy. We have recently determined that the sole cysteine residue of IsiA in Synechocystis sp. PCC 6803 has a critical role in non-photochemical quenching. Similar cysteine-mediated energy quenching has also been observed in green­sulfur bacteria. Sequence analysis of IsiA and CP43 aligns cysteine 260 of IsiA with valine 277 of CP43 in Synechocystis sp. PCC 6803. In the current study, we explore the impact of replacing valine 277 of CP43 to a cysteine on growth, PSII activity and high-light tolerance. Our results imply a decline in the PSII output for the mutant (CP43V277C) presumably due to the dissipation of absorbed light energy by cysteine. Spectroscopic analysis of isolated PSII from this mutant strain also suggests a delayed transfer of excitation energy from CP43-associated chlorophyll a to PSII reaction center. The mutation makes the PSII high-light tolerant and provides a small advantage in growth under high-light conditions. This previously unexplored strategy to engineer high-light tolerance could be a step further towards developing cyanobacterial cells as biofactories.


Assuntos
Complexo de Proteína do Fotossistema II , Synechocystis , Proteínas de Bactérias/metabolismo , Clorofila A/metabolismo , Cisteína/metabolismo , Complexos de Proteínas Captadores de Luz/metabolismo , Complexo de Proteína do Fotossistema II/metabolismo , Synechocystis/genética , Synechocystis/metabolismo , Valina/metabolismo
13.
Int J Food Microbiol ; 377: 109769, 2022 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-35709583

RESUMO

Microbial interaction plays an important role in the assembly of microbial communities in spontaneous food fermentation. Amino acids are important for the microbial interaction. However, the effect of amino acids on the microbial interaction is still unclear in food fermentation. Here, we studied the cross-feeding of amino acids between Saccharomyces cerevisiae and two lactobacilli species (Limosilactobacillus panis and Lentilactobacillis buchneri) from Chinese liquor fermentation. The inoculation of S. cerevisiae and concentrations of amino acids significantly influenced the growth of two lactobacilli species (P < 0.05). Li. panis and Le. buchneri were respectively auxotrophic of 11 and 4 amino acids through single omission technique experiment. S. cerevisiae would promote the growth of Li. panis and Le. buchneri through excreting their essential amino acids, including valine and isoleucine. Herein, we used response surface methodology to establish a predictive model for the growth of lactobacilli species by the regulating factors, the initial concentrations of valine and isoleucine, and inoculum size of S. cerevisiae. Based on the optimized levels of the three factors, the biomass of Li. panis increased from 6.5 ± 0.3 to 7.6 ± 0.1 log10 cells/mL, and the biomass of Le. buchneri increased from 7.2 ± 0.2 to 8.4 ± 0.3 log10 cells/mL. This work revealed the interaction pattern between S. cerevisiae and the two lactobacilli species, it would facilitate the regulation of microbial growth in Chinses liquor fermentation.


Assuntos
Aminoácidos , Saccharomyces cerevisiae , Aminoácidos/metabolismo , Fermentação , Isoleucina/metabolismo , Saccharomyces cerevisiae/metabolismo , Valina/metabolismo
14.
Nutr Diabetes ; 12(1): 20, 2022 04 13.
Artigo em Inglês | MEDLINE | ID: mdl-35418570

RESUMO

OBJECTIVE: Current data regarding the roles of branched-chain amino acids (BCAA) in metabolic health are rather conflicting, as positive and negative effects have been attributed to their intake. METHODS: To address this, individual effects of leucine and valine were elucidated in vivo (C57BL/6JRj mice) with a detailed phenotyping of these supplementations in high-fat (HF) diets and further characterization with in vitro approaches (C2C12 myocytes). RESULTS: Here, we demonstrate that under HF conditions, leucine mediates beneficial effects on adiposity and insulin sensitivity, in part due to increasing energy expenditure-likely contributing partially to the beneficial effects of a higher milk protein intake. On the other hand, valine feeding leads to a worsening of HF-induced health impairments, specifically reducing glucose tolerance/insulin sensitivity. These negative effects are driven by an accumulation of the valine-derived metabolite 3-hydroxyisobutyrate (3-HIB). Higher plasma 3-HIB levels increase basal skeletal muscle glucose uptake which drives glucotoxicity and impairs myocyte insulin signaling. CONCLUSION: These data demonstrate the detrimental role of valine in an HF context and elucidate additional targetable pathways in the etiology of BCAA-induced obesity and insulin resistance.


Assuntos
Aminoácidos de Cadeia Ramificada , Resistência à Insulina , Animais , Glucose/metabolismo , Resistência à Insulina/fisiologia , Leucina/metabolismo , Leucina/farmacologia , Camundongos , Camundongos Endogâmicos C57BL , Músculo Esquelético/metabolismo , Obesidade/metabolismo , Valina/metabolismo , Valina/farmacologia
15.
Sci Rep ; 12(1): 3693, 2022 03 07.
Artigo em Inglês | MEDLINE | ID: mdl-35256693

RESUMO

Both hyperthyroidism and elevated plasma branched chain amino acids (BCAA) are associated with insulin resistance. BCAA utilization and clearance relative to thyroid status changes remains unclear. We investigate amino acids changes, specifically BCAA, during the transition from hyperthyroidism to euthyroidism, and the impact of active brown adipose tissue (BAT) on the metabolic effects of BCAA. Newly diagnosed Graves' disease participants were recruited. Hyperthyroidism was treated via a titration dosing regimen of thionamide anti-thyroid drug to establish euthyroidism over 12-24 weeks. All underwent energy expenditure (EE) measurement within a chamber calorimeter, 18F-fluorodeoxyglucose (18F-FDG) positron-emission tomography/magnetic resonance (PET/MR) imaging and plasma amino acids measurement during hyperthyroidism and euthyroidism. PET BAT maximum standardized uptake value (SUVmax), SUVmean and MR supraclavicular fat fraction (FF) quantified BAT activity. Twenty-two patients completed the study. Plasma BCAA level was significantly reduced in BAT-positive but not in BAT-negative patients during the transition from hyperthyroidism to euthyroidism. Plasma valine but not leucine and isoleucine correlated positively with insulin and HOMA-IR in hyperthyroidism. Plasma valine, leucine and isoleucine correlated with insulin and HOMA-IR in euthyroidism. Plasma valine correlated with insulin and HOMA-IR in BAT-negative but not in BAT-positive participants in both hyperthyroid and euthyroid state. However, the change (i.e. decrease) in plasma valine concentration from hyperthyroid to euthyroid state was affected by BAT-status. BAT utilizes and promotes BCAA plasma clearance from hyperthyroid to euthyroid state. Active BAT can potentially reduce circulating BCAA and may help to ameliorate insulin resistance and improve metabolic health.Clinical trial registration: The trial was registered at clinicaltrials.gov as NCT03064542.


Assuntos
Hipertireoidismo , Resistência à Insulina , Tecido Adiposo Marrom/metabolismo , Aminoácidos de Cadeia Ramificada/metabolismo , Fluordesoxiglucose F18/metabolismo , Humanos , Hipertireoidismo/metabolismo , Insulina/metabolismo , Isoleucina/metabolismo , Leucina/metabolismo , Valina/metabolismo
16.
Sci Rep ; 12(1): 4131, 2022 03 08.
Artigo em Inglês | MEDLINE | ID: mdl-35260782

RESUMO

Profound tuberculosis (TB)-induced metabolic changes reflected in the blood metabolomic profile may provide an opportunity to identify specific markers of Mycobacterium tuberculosis infection. Using targeted liquid chromatography tandem mass spectrometry, we compared the levels of 30 small metabolites, including amino acids and derivatives, and small organic compounds in serum and M.tb antigen-stimulated whole blood cultures of active TB children, latent TB (LTBI) children, nonmycobacterial pneumonia (NMP) children, and healthy controls (HCs) to assess their potential as biomarkers of childhood TB. We found elevated levels of leucine and kynurenine combined with reduced concentrations of citrulline and glutamine in serum and blood cultures of TB and LTBI groups. LTBI status was additionally associated with a decrease in valine levels in blood cultures. The NMP metabolite profile was characterized by an increase in citrulline and glutamine and a decrease in leucine, kynurenine and valine concentrations. The highest discriminatory potential for identifying M.tb infection was observed for leucine detected in serum and kynurenine in stimulated blood cultures. The use of targeted metabolomics may reveal metabolic changes in M.tb-infected children, and the obtained results are a proof of principle of the usefulness of metabolites in the auxiliary diagnosis of TB in children.


Assuntos
Tuberculose Latente , Mycobacterium tuberculosis , Tuberculose , Biomarcadores , Hemocultura , Criança , Citrulina/metabolismo , Glutamina/metabolismo , Humanos , Cinurenina/metabolismo , Tuberculose Latente/diagnóstico , Tuberculose Latente/microbiologia , Leucina/metabolismo , Metabolômica , Mycobacterium tuberculosis/metabolismo , Tuberculose/diagnóstico , Valina/metabolismo
17.
J Biosci Bioeng ; 133(5): 436-443, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35216933

RESUMO

Isoleucyl-tRNA synthetase (IleRS), leucyl-tRNA synthetase (LeuRS), and valyl-tRNA synthetase (ValRS) are enzymes that have potential for the determination of l-isoleucine, l-leucine, and l-valine in food products and plasma. However, the disadvantages of these enzymes are their specificity and sensitivity. Here, we examined the substrate specificity of IleRS, LeuRS, and ValRS under various conditions of pyrophosphate amplification to improve their specificity and sensitivity. The amount of pyrophosphate produced in IleRS, LeuRS, and ValRS reactions was amplified after the addition of excess adenosine-5'-triphosphate and magnesium ions, and was approximately 9-, 8-, and 7-fold higher, respectively, for each of the initial l-amino acid substrates (50 µM). However, in addition to their target amino acids, IleRS, LeuRS, and ValRS also reacted with l-valine, l-lysine, and l-threonine, respectively. This substrate misrecognition was overcome by making the reaction pH more acidic and by increasing the magnesium ion concentration. The pyrophosphate amplification in IleRS, LeuRS, and ValRS reactions resulted in the production of p1, p4-di (adenosine) 5'-tetraphosphate. We also observed a strong positive correlation (R = 0.99) between the amount of pyrophosphate produced and the initial concentration of l-amino acid with 5 and 50 µM l-isoleucine, l-leucine, and l-valine. Our results suggest that amino acid assays using IleRS, LeuRS, and ValRS are promising methods to accurately measure l-valine, l-isoleucine, and l-leucine in food products and plasma.


Assuntos
Aminoacil-tRNA Sintetases , Leucina-tRNA Ligase , Adenosina/metabolismo , Aminoácidos/metabolismo , Aminoacil-tRNA Sintetases/metabolismo , Difosfatos , Escherichia coli/metabolismo , Isoleucina , Leucina/metabolismo , Leucina-tRNA Ligase/química , Leucina-tRNA Ligase/genética , Leucina-tRNA Ligase/metabolismo , Magnésio/metabolismo , RNA de Transferência , Especificidade por Substrato , Valina/metabolismo , Valina-tRNA Ligase/química , Valina-tRNA Ligase/genética , Valina-tRNA Ligase/metabolismo
18.
Br Poult Sci ; 63(4): 552-556, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35164618

RESUMO

1. Cobb and Ross broilers (200 of each sex and breed) were fed four phases of diets ad libitum formulated with balanced protein to match their amino acid requirements throughout growth. Ten birds per genotype were sampled and euthanised at two-weekly intervals from 14 to 112 d of age. All feathers were dry-plucked from each of the seven tracts (specific skin areas) and pulp (the centre of the feather filament) was removed from primary and secondary remiges.2. Daily losses of feathers were collected from an additional 20 individually-caged broilers of each breed. These feathers were separated into natal down, contour feathers, remiges and rectrices and then pooled by type, sex and genotype to quantify water and protein contents. Only those feathers collected from male Cobb 500 MX broilers were analysed for amino acid content.3. Amino acid contents of feathers from the seven tracts were measured only in Cobb males on days 1, 28 and 70; for pulp on days 28 and 70; and for the four types of moulted feathers.4. Protein content on a dry matter basis remained relatively constant over all ages and tracts during growth. Water content decreased with age in both sexes and genotype. Lysine and methionine content in feathers decreased with age while cystine, valine, leucine and serine increased. Lysine, methionine and histidine levels were higher in pulp than in mature feathers whereas cystine and valine were higher in mature feathers than in pulp.5. These results, together with information about moulting patterns in broilers, enabled the effects of age of the bird and of the type of feather, to be taken into account when determining the rate of deposition of amino acids in feathers.


Assuntos
Galinhas , Plumas , Aminoácidos/metabolismo , Animais , Cistina/metabolismo , Plumas/química , Feminino , Genótipo , Lisina/análise , Masculino , Metionina/metabolismo , Proteínas/análise , Valina/análise , Valina/metabolismo , Água/análise
19.
Leukemia ; 36(3): 821-833, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34599272

RESUMO

Little is known of hematopoietic stem (HSC) and progenitor (HPC) cell self-renewal. The role of Brahma (BRM), a chromatin remodeler, in HSC function is unknown. Bone marrow (BM) from Brm-/- mice manifested increased numbers of long- and short-term HSCs, GMPs, and increased numbers and cycling of functional HPCs. However, increased Brm-/- BM HSC numbers had decreased secondary and tertiary engraftment, suggesting BRM enhances HSC self-renewal. Valine was elevated in lineage negative Brm-/- BM cells, linking intracellular valine with Brm expression. Valine enhanced HPC colony formation, replating of human cord blood (CB) HPC-derived colonies, mouse BM and human CB HPC survival in vitro, and ex vivo expansion of normal mouse BM HSCs and HPCs. Valine increased oxygen consumption rates of WT cells. BRM through CD98 was linked to regulated import of branched chain amino acids, such as valine, in HPCs. Brm-/- LSK cells exhibited upregulated interferon response/cell cycle gene programs. Effects of BRM depletion are less apparent on isolated HSCs compared to HSCs in the presence of HPCs, suggesting cell extrinsic effects on HSCs. Thus, intracellular valine is regulated by BRM expression in HPCs, and the BRM/valine axis regulates HSC and HPC self-renewal, proliferation, and possibly differentiation fate decisions.


Assuntos
Autorrenovação Celular , Montagem e Desmontagem da Cromatina , Células-Tronco Hematopoéticas/citologia , Fatores de Transcrição/metabolismo , Valina/metabolismo , Animais , Células Cultivadas , Deleção de Genes , Células-Tronco Hematopoéticas/metabolismo , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Fatores de Transcrição/genética
20.
Nature ; 601(7893): 428-433, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34937946

RESUMO

Although deregulation of transfer RNA (tRNA) biogenesis promotes the translation of pro-tumorigenic mRNAs in cancers1,2, the mechanisms and consequences of tRNA deregulation in tumorigenesis are poorly understood. Here we use a CRISPR-Cas9 screen to focus on genes that have been implicated in tRNA biogenesis, and identify a mechanism by which altered valine tRNA biogenesis enhances mitochondrial bioenergetics in T cell acute lymphoblastic leukaemia (T-ALL). Expression of valine aminoacyl tRNA synthetase is transcriptionally upregulated by NOTCH1, a key oncogene in T-ALL, underlining a role for oncogenic transcriptional programs in coordinating tRNA supply and demand. Limiting valine bioavailability through restriction of dietary valine intake disrupted this balance in mice, resulting in decreased leukaemic burden and increased survival in vivo. Mechanistically, valine restriction reduced translation rates of mRNAs that encode subunits of mitochondrial complex I, leading to defective assembly of complex I and impaired oxidative phosphorylation. Finally, a genome-wide CRISPR-Cas9 loss-of-function screen in differential valine conditions identified several genes, including SLC7A5 and BCL2, whose genetic ablation or pharmacological inhibition synergized with valine restriction to reduce T-ALL growth. Our findings identify tRNA deregulation as a critical adaptation in the pathogenesis of T-ALL and provide a molecular basis for the use of dietary approaches to target tRNA biogenesis in blood malignancies.


Assuntos
Leucemia-Linfoma Linfoblástico de Células T Precursoras , Valina-tRNA Ligase , Valina , Animais , Disponibilidade Biológica , Sistemas CRISPR-Cas , Dieta , Complexo I de Transporte de Elétrons/genética , Transportador 1 de Aminoácidos Neutros Grandes , Camundongos , Mitocôndrias/metabolismo , Fosforilação Oxidativa , Leucemia-Linfoma Linfoblástico de Células T Precursoras/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2 , RNA de Transferência/genética , Valina/metabolismo , Valina-tRNA Ligase/metabolismo
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