scholarly journals De novoβ-alanine synthesis in α-proteobacteria involves a β-alanine synthase from the uracil degradation pathway

2019 ◽  
Author(s):  
Mariana López-Sámano ◽  
Luis Fernando Lozano-Aguirre Beltrán ◽  
Rosina Sánchez-Thomas ◽  
Araceli Dávalos ◽  
Tomás Villaseñor ◽  
...  
Keyword(s):  
De Novo ◽  
Enzymatic Reaction ◽  
Pantothenic Acid ◽  
Acid Synthesis ◽  
Degradation Pathway ◽  
Partial Conservation ◽  
Alanine Synthesis ◽  
Pyrimidine Degradation ◽  
Cloned Gene

Abstractβ-alanine synthesis in bacteria occurs by the decarboxylation of L-aspartate as part of the pantothenate synthesis pathway. In the other two domains of life we find different pathways for β-alanine formation, such as sources from spermine in plants, uracil in yeast and by transamination reactions in insects and mammals. There are also promiscuous decarboxylases that can decarboxylate aspartate. Several bioinformatics studies about the conservation of pantothenate synthesis pathway performed on bacteria, archaea and eukaryotes, have shown a partial conservation of the pathway. As a part of our work, we performed an analysis of the prevalence of reported β-alanine synthesis pathways in 204 genomes of alpha-proteobacteria, with a focus on theRhizobialesorder. The aim of this work was to determine the enzyme or pathway used to synthetize β-alanine inRhizobium etliCFN42. Our bioinformatics analysis showed that this strain encodes the pyrimidine degradation pathway in its genome. We obtained a β-alanine synthase (amaB)mutant that was a β-alanine auxotroph. Complementation with the cloned gene restored the wild type phenotype. Biochemical analysis confirmed that the recombinant AmaB catalyzed the formation of β-alanine from 3-Ureidopropionic acidin vitro. Here we show a different way in bacteria to produce this essential metabolite.ImportanceSince the pioneer studies of Cronan (1980) on β-alanine synthesis inE. coli, it has been assumed that the decarboxilation of aspartate by the L-aspartate-α-decarboxylase it’s the main enzymatic reaction for β-alanine synthesis in bacteria. Forty years later, while we were studying the pantothenic acid synthesis in rhizobia, we demonstrate that a numerous and diverse group of bacteria classified as α-proteobacteria synthesize β-alaninede novousing β-alanine synthase, the last enzyme from the reductive pathway for uracil degradation.Additionally, there is a growing interest in β-amino acid due to its remarkable pharmaceuticals properties as hypoglycemic, antiketogenic and anti-fungal agents.

Effect of carbohydrate intake on de novo lipogenesis in human adipose tissue

1987 ◽  
Vol 253 (6) ◽  
pp. E664-E669 ◽  
Author(s):  
C. Chascione ◽  
D. H. Elwyn ◽  
M. Davila ◽  
K. M. Gil ◽  
J. Askanazi ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
De Novo ◽  
Acid Synthesis ◽  
De Novo Lipogenesis ◽  
Whole Body ◽  
High Intake ◽  
Carbohydrate Diet ◽  
Triglyceride Synthesis ◽  
High Carbohydrate

Rates of synthesis, from [14C]glucose, of fatty acids (de novo lipogenesis) and glycerol (triglyceride synthesis) were measured in biopsies of adipose tissue from nutritionally depleted patients given low- or high-carbohydrate intravenous nutrition. Simultaneously, energy expenditure and whole-body lipogenesis were measured by indirect calorimetry. Rates of whole-body lipogenesis were zero on the low-carbohydrate diet and averaged 1.6 g.kg-1.day-1 on the high-carbohydrate diet. In vitro rates of triglyceride synthesis increased 3-fold going from the low to the high intake; rates of fatty acid synthesis increased approximately 80-fold. In vitro, lipogenesis accounted for less than 0.1% of triglyceride synthesis on the low intake and 4% on the high intake. On the high-carbohydrate intake, in vitro rates of triglyceride synthesis accounted for 61% of the rates of unidirectional triglyceride synthesis measured by indirect calorimetry. In vitro rates of lipogenesis accounted for 7% of whole-body lipogenesis. Discrepancies between in vitro rates of fatty acid synthesis from glucose, compared with acetate and citrate, as reported by others, suggest that in depleted patients on hypercaloric high-carbohydrate diets, adipose tissue may account for up to 40% of whole-body lipogenesis.

Effects of Actinomycin D on Purine Ribonucleotide Metabolism in Ehrlich Ascites Tumor Cells In Vitro

1974 ◽  
Vol 52 (3) ◽  
pp. 263-267 ◽  
Author(s):  
Floyd F. Snyder ◽  
J. Frank Henderson
Keyword(s):  
Tumor Cells ◽  
Actinomycin D ◽  
De Novo ◽  
Acid Synthesis ◽  
Purine Metabolism ◽  
Ehrlich Ascites Tumor ◽  
Ehrlich Ascites Tumor Cells ◽  
Ascites Tumor ◽  
Ehrlich Ascites

Actinomycin D treatment of Ehrlich ascites tumor cells in vitro causes slight to moderate inhibition of purine ribonucleotide synthesis de novo and from purine bases, and strong inhibition of inosinate dehydrogenase activity. These effects have the same dose–response relationship as inhibition of RNA synthesis by this drug. Daunomycin has similar effects on purine metabolism at a concentration that substantially inhibits nucleic acid synthesis. Actinomycin D treatment leads to elevated intracellular concentrations of ATP and GTP, and the effects of this drug on purine metabolism are believed to be mediated by these purine ribonucleoside triphosphates.

scholarly journals USP22-dependent accumulation of lipidomes drives hepatocellular carcinoma progression by stabilizing PPARγ

2020 ◽  
Author(s):  
Zhen Ning ◽  
Xin Guo ◽  
Xiaolong Liu ◽  
Chang Lu ◽  
Aman Wang ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Fatty Acid ◽  
Molecular Mechanism ◽  
Fatty Acid Synthesis ◽  
De Novo ◽  
Acid Synthesis ◽  
Specific Protease ◽  
Pparγ Expression

Abstract Elevated de novo lipogenesis (DNL) is considered to be a crucial factor in hepatocellular carcinoma (HCC) development. However, the molecular mechanism for its occurrence in HCC is still unclear. Herein, we identified ubiquitin-specific protease 22 (USP22) as a key regulator for de novo fatty acid synthesis, which directly interacts with, deubiquitinates and stabilizes PPARγ through K48-linked deubiquitination, and in turn, this stabilization increases ACC and ACLY transcription. In addition, we found that USP22 promoted the de novo synthesis of fatty acid labeling from glucose tracers. USP22-dysregulated de novo fatty acid synthesis contributes to HCC progression, but USP22 was functionality suppressed by inhibiting the expression of PPARγ, ACLY, or ACC in in vitro cell proliferation and in vivo tumorigenesis experiments. In HCC, USP22 expression positively correlates with PPARγ expression, and simultaneously, high expression of USP22 and PPARγ or USP22, ACC and ACLY is associated with a poor prognosis. Taken together, we identified a previously undescribed USP22-regulated lipogenesis molecular mechanism that involves the PPARγ-ACLY/ACC axis in HCC tumorigenesis and provide a rationale for therapeutic targeting of lipogenesis via USP22 inhibition.

scholarly journals Taurine-Mediated IDOL Contributes to Resolution of Streptococcus uberis Infection

2021 ◽  
Vol 89 (5) ◽  
Author(s):  
Zhixin Wan ◽  
Riguo Lan ◽  
Yilin Zhou ◽  
Yuanyuan Xu ◽  
Zhenglei Wang ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Lipid Metabolism ◽  
Fatty Acid Synthesis ◽  
De Novo ◽  
Bacterial Load ◽  
Critical Role ◽  
Acid Synthesis ◽  
Content Type ◽  
Streptococcus Uberis

ABSTRACT Metabolic alterations occur in pathogenic infections, but the role of lipid metabolism in the progression of bacterial mastitis is unclear. Cross talk between lipid droplets (LDs) and invading bacteria occurs, and targeting of de novo lipogenesis inhibits pathogen reproduction. In this study, we investigate the role(s) of lipid metabolism in mammary cells during Streptococcus uberis infection. Our results indicate that S. uberis induces the synthesis of fatty acids and production of LDs. Importantly, taurine reduces fatty acid synthesis, the abundance of LDs and the in vitro bacterial load of S. uberis. These changes are mediated, at least partly, by the E3 ubiquitin ligase IDOL, which is associated with the degradation of low-density lipoprotein receptors (LDLRs). We have identified a critical role for IDOL-mediated fatty acid synthesis in bacterial infection, and we suggest that taurine may be an effective prophylactic or therapeutic strategy for preventing S. uberis mastitis.

scholarly journals The contrary intracellular and extracellular functions of PEDF in HCC development

2019 ◽  
Vol 10 (10) ◽  
Author(s):  
Cen Li ◽  
Zhijian Huang ◽  
Liuqing Zhu ◽  
Xianhuan Yu ◽  
Tianxiao Gao ◽  
...  
Keyword(s):  
De Novo ◽  
Pigment Epithelium ◽  
Animal Experiments ◽  
Underlying Mechanism ◽  
Acid Synthesis ◽  
Angiogenic Inhibitor ◽  
Growth Activation ◽  
Ubiquitin Proteasome

Abstract Pigment epithelium-derived factor (PEDF), a classic angiogenic inhibitor, has been reported to function as a tumor suppression protein and to downregulate in many types of solid tumors. However, the expression level of PEDF and its role in hepatocellular carcinoma (HCC) are contradictory. The present study investigates the expression and different activities of secreted and intracellular PEDF during HCC development, as well as the underlying mechanism of PEDF on HCC lipid disorders. We found that PEDF had no association with patients’ prognosis, although PEDF was highly expressed and inhibited angiogenesis in HCC tumor tissues. The animal experiments indicated that full-length PEDF exhibited equalizing effects on tumor growth activation and tumor angiogenesis inhibition in the late stage of HCC progression. Importantly, the pro-tumor activity was mediated by the intracellular PEDF, which causes accumulation of free fatty acids (FFAs) in vivo and in vitro. Based on the correlation analysis of PEDF and lipid metabolic indexes in human HCC tissues, we demonstrated that the intracellular PEDF led to the accumulation of FFA and eventually promoted HCC cell growth by inhibiting the activation of AMPK via ubiquitin–proteasome-mediated degradation, which causes increased de novo fatty acid synthesis and decreased FFA oxidation. Our findings revealed why elevated PEDF did not improve the patients’ prognosis as the offsetting intracellular and extracellular activities. This study will lead to a comprehensive understanding of the diverse role of PEDF in HCC and provide a new selective strategy by supplement of extracellular PEDF and downregulation of intracellular PEDF for the prevention and treatment of liver cancer.

De novo synthesis of fructo-oligosaccharides in leaf disks of certain Asteraceae

1972 ◽  
Vol 50 (2) ◽  
pp. 295-303 ◽  
Author(s):  
K. R. Chandorkar ◽  
F. W. Collins
Keyword(s):  
Chain Length ◽  
De Novo ◽  
Close Correlation ◽  
Acid Synthesis ◽  
Degree Of Polymerization ◽  
De Novo Synthesis ◽  
The Relationship ◽  
Leaf Disks

Incubation of leaf disks of certain genera of Asteraceae on phosphate-buffered, 5% sugar solutions resulted in the de novo synthesis of a homologous series of inulin-type fructosans. Fructo-oligosaccharides of degree of polymerization 3 to 21 or 22 were present in dandelion, chicory, lettuce, hawkweed, and sow thistle leaf disks after 72 h, but not in dahlia or sunflower. Synthesis occurred with media containing either fructose, glucose, or sucrose, but not with mannose or galactose. Fructosan formation began after about 36 h and continued with the sequential synthesis of homologs of increasing chain length. After 72 h, the relationship between the amount of polymer synthesized and the chain length appeared to be logarithmically biphasic, consisting of two series of exponentially decreasing values. Incubation for 120 h however, resulted in a distribution more closely resembling that found naturally in fructosan storing tissues. 14C-tracer studies showed that both the endogenous and exogenous carbohydrate sources contribute to fructosan synthesis. Fructo-oligosaccharide formation was blocked by cycloheximide, puromycin, and actinomycin D but not chloramphenicol, indicating that cytoplasmic protein and nucleic acid synthesis was required. Analysis of fructosan formation during incubation suggests a close correlation between transfructosylation mechanisms observed in vitro and the de novo synthesis of fructosans in vivo.

scholarly journals Mutations in the Saccharomyces cerevisiae opi3 gene: effects on phospholipid methylation, growth and cross-pathway regulation of inositol synthesis.

Genetics ◽  
1989 ◽  
Vol 122 (2) ◽  
pp. 317-330 ◽  
Author(s):  
P McGraw ◽  
S A Henry
Keyword(s):  
Stationary Phase ◽  
De Novo ◽  
Growth Conditions ◽  
Temperature Sensitive ◽  
Phase Growth ◽  
Gene Effects ◽  
Growth Defects ◽  
Pathway Regulation ◽  
Cloned Gene

Abstract We report the isolation of two new opi3 mutants by EMS mutagenesis, and construction of an insertion allele in vitro using the cloned gene. We have demonstrated that the opi3 mutations cause a deficiency in the two terminal phospholipid N-methyltransferase (PLMT) activities required for the de novo synthesis of PC (phosphatidylcholine). The opi3 mutants, under certain growth conditions, produce membrane virtually devoid of PC although, surprisingly, none of the mutants displays a strict auxotrophic requirement for choline. Although the opi3 mutants grow without supplements, we have shown that the atypical membrane affects the ability of the mutant strains to initiate log phase growth and to sustain viability at stationary phase. The commencement of log phase growth is enhanced by addition of choline or to a lesser extent DME (dimethylethanolamine), and retarded by addition of MME (monomethylethanolamine). The mutant cells lose viability at the stationary phase of the cell cycle in the absence of DME or choline, and are also temperature sensitive for growth at 37 degrees especially in media containing MME. These growth defects have been correlated to the presence of specific phospholipids in the membrane. The opi3 growth defects are suppressed by an unusual mutation in the phospholipid methylation pathway that perturbs the N-methyltransferase (PEMT) activity immediately preceding the reactions affected by the opi3 lesion. We believe this mutation, cho2-S, alters the substrate specificity of the PEMT. A secondary effect of opi3 mutations is disruption of the cross pathway regulation of the synthesis of the PI (phosphatidylinositol) precursor inositol. Synthesis of inositol is controlled through regulation of the INO1 gene which encodes inositol-1-phosphate synthase. This highly regulated gene is expressed constitutively in opi3 mutants. We have used the opi3 strains to demonstrate that synthesis of either PC or PD (phosphatidyldimethylethanolamine) will restore normal regulation of the INO1 gene.

Upregulation of adipocyte metabolism by agouti protein: possible paracrine actions in yellow mouse obesity

1996 ◽  
Vol 270 (1) ◽  
pp. E192-E196 ◽  
Author(s):  
B. H. Jones ◽  
J. H. Kim ◽  
M. B. Zemel ◽  
R. P. Woychik ◽  
E. J. Michaud ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Synthase ◽  
De Novo ◽  
Ectopic Expression ◽  
Acid Synthesis ◽  
Mrna Levels ◽  
Simultaneous Treatment ◽  
Agouti Protein ◽  
Agouti Gene

Mutations leading to ectopic expression of the murine agouti gene (a) result in progressive obesity. To further characterize this model, we analyzed adipose and hepatic mRNA levels for fatty acid synthase (FAS) and stearoyl-CoA desaturase (SCD), two key enzymes in de novo fatty acid synthesis and desaturation, respectively. FAS and SCD mRNA in both tissues of obese (Avy) mice were dramatically increased relative to lean (ala) controls. Excessive expression of these genes in this model could be due to direct effects of the agouti gene product; to test this possibility we treated 3T3-L1 adipocytes in vitro with recombinant agouti protein. Agouti treatment increased FAS and SCD mRNA levels by 1.5- and 4-fold, respectively. In addition, FAS activity and triglyceride content were 3-fold higher in agoutitreated 3T3-L1 cells relative to controls; these effects were attenuated by simultaneous treatment with a calcium channel blocker (nitrendipine). These data demonstrate that the agouti protein can directly increase lipogenesis in adipocytes and suggest that these effects are mediated through an intracellular calcium-dependent mechanism.

scholarly journals The plastidial Arabidopsis thaliana NFU1 protein binds and delivers [4Fe-4S] clusters to specific client proteins

2020 ◽  
Vol 295 (6) ◽  
pp. 1727-1742 ◽  
Author(s):  
Mélanie Roland ◽  
Jonathan Przybyla-Toscano ◽  
Florence Vignols ◽  
Nathalie Berger ◽  
Tamanna Azam ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
De Novo ◽  
Acid Synthesis ◽  
Bimolecular Fluorescence Complementation ◽  
Cluster Assembly ◽  
Amino Acid Synthesis ◽  
Cluster Transfer ◽  
Client Proteins ◽  
Branched Chain

Proteins incorporating iron–sulfur (Fe-S) co-factors are required for a plethora of metabolic processes. Their maturation depends on three Fe-S cluster assembly machineries in plants, located in the cytosol, mitochondria, and chloroplasts. After de novo formation on scaffold proteins, transfer proteins load Fe-S clusters onto client proteins. Among the plastidial representatives of these transfer proteins, NFU2 and NFU3 are required for the maturation of the [4Fe-4S] clusters present in photosystem I subunits, acting upstream of the high-chlorophyll fluorescence 101 (HCF101) protein. NFU2 is also required for the maturation of the [2Fe-2S]-containing dihydroxyacid dehydratase, important for branched-chain amino acid synthesis. Here, we report that recombinant Arabidopsis thaliana NFU1 assembles one [4Fe-4S] cluster per homodimer. Performing co-immunoprecipitation experiments and assessing physical interactions of NFU1 with many [4Fe-4S]-containing plastidial proteins in binary yeast two-hybrid assays, we also gained insights into the specificity of NFU1 for the maturation of chloroplastic Fe-S proteins. Using bimolecular fluorescence complementation and in vitro Fe-S cluster transfer experiments, we confirmed interactions with two proteins involved in isoprenoid and thiamine biosynthesis, 1-hydroxy-2-methyl-2-(E)-butenyl-4-diphosphate synthase and 4-amino-5-hydroxymethyl-2-methylpyrimidine phosphate synthase, respectively. An additional interaction detected with the scaffold protein SUFD enabled us to build a model in which NFU1 receives its Fe-S cluster from the SUFBC2D scaffold complex and serves in the maturation of specific [4Fe-4S] client proteins. The identification of the NFU1 partner proteins reported here more clearly defines the role of NFU1 in Fe-S client protein maturation in Arabidopsis chloroplasts among other SUF components.

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