Arabidopsis 4-COUMAROYL-COA LIGASE 8 contributes to the biosynthesis of the benzenoid ring of coenzyme Q in peroxisomes

2019 ◽  
Vol 476 (22) ◽  
pp. 3521-3532
Author(s):  
Eric Soubeyrand ◽  
Megan Kelly ◽  
Shea A. Keene ◽  
Ann C. Bernert ◽  
Scott Latimer ◽  
...  
Keyword(s):  
Oxidative Metabolism ◽  
Time Course ◽  
Reverse Genetics ◽  
De Novo ◽  
Coenzyme Q ◽  
Control Level ◽  
Wild Type ◽  
Fluorescent Reporters ◽  
Coa Ligase ◽  
Peroxisomal Targeting

Plants have evolved the ability to derive the benzenoid moiety of the respiratory cofactor and antioxidant, ubiquinone (coenzyme Q), either from the β-oxidative metabolism of p-coumarate or from the peroxidative cleavage of kaempferol. Here, isotopic feeding assays, gene co-expression analysis and reverse genetics identified Arabidopsis 4-COUMARATE-COA LIGASE 8 (4-CL8; At5g38120) as a contributor to the β-oxidation of p-coumarate for ubiquinone biosynthesis. The enzyme is part of the same clade (V) of acyl-activating enzymes than At4g19010, a p-coumarate CoA ligase known to play a central role in the conversion of p-coumarate into 4-hydroxybenzoate. A 4-cl8 T-DNA knockout displayed a 20% decrease in ubiquinone content compared with wild-type plants, while 4-CL8 overexpression boosted ubiquinone content up to 150% of the control level. Similarly, the isotopic enrichment of ubiquinone's ring was decreased by 28% in the 4-cl8 knockout as compared with wild-type controls when Phe-[Ring-13C6] was fed to the plants. This metabolic blockage could be bypassed via the exogenous supply of 4-hydroxybenzoate, the product of p-coumarate β-oxidation. Arabidopsis 4-CL8 displays a canonical peroxisomal targeting sequence type 1, and confocal microscopy experiments using fused fluorescent reporters demonstrated that this enzyme is imported into peroxisomes. Time course feeding assays using Phe-[Ring-13C6] in a series of Arabidopsis single and double knockouts blocked in the β-oxidative metabolism of p-coumarate (4-cl8; at4g19010; at4g19010 × 4-cl8), flavonol biosynthesis (flavanone-3-hydroxylase), or both (at4g19010 × flavanone-3-hydroxylase) indicated that continuous high light treatments (500 µE m−2 s−1; 24 h) markedly stimulated the de novo biosynthesis of ubiquinone independently of kaempferol catabolism.

Alteration of gene expression in tomato plants (Lycopersicon esculentum) by drought and salt stress

Genome ◽  
1992 ◽  
Vol 35 (3) ◽  
pp. 385-391 ◽  
Author(s):  
R. D. Chen ◽  
Z. Tabaeizadeh
Keyword(s):  
Protein Synthesis ◽  
Salt Stress ◽  
Drought Stress ◽  
Lycopersicon Esculentum ◽  
Time Course ◽  
De Novo ◽  
Polyacrylamide Gel Electrophoresis ◽  
Control Level ◽  
Protein Patterns ◽  
Stress Injury

The effect of drought and NaCl treatments on polypeptide levels in both roots and leaves of tomato (Lycopersicon esculentum) seedlings was analyzed using two-dimensional polyacrylamide gel electrophoresis. In roots, comparison of silver-stained protein patterns showed that during drought treatment two proteins were highly accumulated and after rehydration they returned to the control level. The same changes were also observed under salinity stress. Moreover, salt treatment induced stress-specific proteins. In leaves, the in vivo labelling of intact leaves with 35S-labelled methionine showed that drought stress resulted in progressive changes in the protein pattern. There is de novo synthesis of proteins and repression of preexisting protein synthesis. The time course of appearance of newly synthesized proteins was different during water stress. The changes in proteins were usually reversible after rehydration of the seedlings. Leaves of NaCl-treated plants did not synthesize any salt stress specific polypeptides, but the synthesis of several drought-modulated proteins was affected. It is suggested that the quantitative and qualitative changes in protein synthesis may contribute to stress-resistant or stress-injury mechanisms.Key words: drought stress, Lycopersicon esculentum, protein synthesis, salt stress.

Postnatal growth rate and gonadal development in circadian tau mutant hamsters reared in constant dim red light

Reproduction ◽  
2000 ◽  
pp. 327-330 ◽  
Author(s):  
RJ Lucas ◽  
JA Stirland ◽  
YN Mohammad ◽  
AS Loudon
Keyword(s):  
Time Course ◽  
Red Light ◽  
Somatic Growth ◽  
Postnatal Growth ◽  
Gonadal Development ◽  
Testicular Development ◽  
Wild Type ◽  
Similar Time ◽  
Syrian Hamsters ◽  
Body Weights

The role of the circadian clock in the reproductive development of Syrian hamsters (Mesocricetus auratus was examined in wild type and circadian tau mutant hamsters reared from birth to 26 weeks of age under constant dim red light. Testis diameter and body weights were determined at weekly intervals in male hamsters from 4 weeks of age. In both genotypes, testicular development, subsequent regression and recrudescence exhibited a similar time course. The age at which animals displayed reproductive photosensitivity, as exhibited by testicular regression, was unrelated to circadian genotype (mean +/- SEM: 54 +/- 3 days for wild type and 59 +/- 5 days for tau mutants). In contrast, our studies revealed a significant impact of the mutation on somatic growth, such that tau mutants weighed 18% less than wild types at the end of the experiment. Our study reveals that the juvenile onset of reproductive photoperiodism in Syrian hamsters is not timed by the circadian system.

BioMime – A Sirolimus-eluting Coronary Stent System for the Treatment of Patients with De Novo Coronary Lesions – meriT-1 Report

2011 ◽  
Vol 6 (1) ◽  
pp. 39
Author(s):  
Keyword(s):  
Stent Thrombosis ◽  
Time Course ◽  
De Novo ◽  
Drug Eluting Stent ◽  
Cobalt Chromium ◽  
Cardiac Events ◽  
End Points ◽  
Safety And Efficacy ◽  
Binary Restenosis

Background:Since the first reported use of percutaneous transluminal coronary angioplasty, advances in the interventional cardiology arena have been fast paced. Developers and clinicians are adapting from the learning curve awarded by the time-course of drug-eluting stent (DES) evolution. BioMime™ sirolimus-eluting stent (SES) is a step towards biomimicry. The stent is built on a strut of ultra-low thickness (65μm), a cobalt–chromium platform using an intelligent hybrid of closed and open cells allowing for morphology-mediated expansion. It employs a well-known antiproliferative – sirolimus – that elutes from a known biodegradable copolymer formulation within 30 days. The resultant stent demonstrates almost 100% endothelialisation at 30 days in preclinical models.Methods:The meriT-1 was a prospective, single-arm, single-centre trial to evaluate the safety and efficacy of BioMime SES in 30 patients with a single de novo lesion in native coronary arteries. The primary safety and efficacy end-points were major adverse cardiac events (MACE) at 30 days and in-stent late lumen loss at eight months, as measured using quantitative coronary angiographic (QCA) method. Secondary safety and efficacy end-points included MACE at one and two years and angiographic binary restenosis at eight-month angiographic follow-up. Other end-points included the occurrence of stent thrombosis at acute, subacute, late and very late periods and the percentage of diameter stenosis by QCA.Results:No MACE were observed and the median in-stent late luminal loss in 20 (67%) subjects studied by QCA was 0.15mm, with 0% binary restenosis at eight-month follow-up. No stent thrombosis was observed up to one-year follow-up.Conclusions:In comparison to currently available DES, BioMime SES appears to have a considerable scientific basis for prevention of neointimal proliferation, restenosis and associated clinical events.

scholarly journals Lipid Metabolism Is Dysregulated before, during and after Pregnancy in a Mouse Model of Gestational Diabetes

2021 ◽  
Vol 22 (14) ◽  
pp. 7452
Author(s):  
Samuel Furse ◽  
Denise S. Fernandez-Twinn ◽  
Davide Chiarugi ◽  
Albert Koulman ◽  
Susan E. Ozanne
Keyword(s):  
Lipid Metabolism ◽  
Gestational Diabetes ◽  
Glucose Tolerance ◽  
Mouse Model ◽  
Time Course ◽  
De Novo ◽  
Lipid Analysis ◽  
Temporal Distribution ◽  
De Novo Lipogenesis ◽  
Analysis Tool

The aim of the current study was to test the hypothesis that maternal lipid metabolism was modulated during normal pregnancy and that these modulations are altered in gestational diabetes mellitus (GDM). We tested this hypothesis using an established mouse model of diet-induced obesity with pregnancy-associated loss of glucose tolerance and a novel lipid analysis tool, Lipid Traffic Analysis, that uses the temporal distribution of lipids to identify differences in the control of lipid metabolism through a time course. Our results suggest that the start of pregnancy is associated with several changes in lipid metabolism, including fewer variables associated with de novo lipogenesis and fewer PUFA-containing lipids in the circulation. Several of the changes in lipid metabolism in healthy pregnancies were less apparent or occurred later in dams who developed GDM. Some changes in maternal lipid metabolism in the obese-GDM group were so late as to only occur as the control dams’ systems began to switch back towards the non-pregnant state. These results demonstrate that lipid metabolism is modulated in healthy pregnancy and the timing of these changes is altered in GDM pregnancies. These findings raise important questions about how lipid metabolism contributes to changes in metabolism during healthy pregnancies. Furthermore, as alterations in the lipidome are present before the loss of glucose tolerance, they could contribute to the development of GDM mechanistically.

scholarly journals Snf1 Is a Regulator of Lipid Accumulation in Yarrowia lipolytica

2013 ◽  
Vol 79 (23) ◽  
pp. 7360-7370 ◽  
Author(s):  
John Seip ◽  
Raymond Jackson ◽  
Hongxian He ◽  
Quinn Zhu ◽  
Seung-Pyo Hong
Keyword(s):  
Yarrowia Lipolytica ◽  
Lipid Accumulation ◽  
Oleaginous Yeast ◽  
De Novo ◽  
Lipid Synthesis ◽  
Omega 3 ◽  
Wild Type ◽  
Content Type ◽  
Reverse Transcription Pcr ◽  
Dry Cell Weight

ABSTRACTIn the oleaginous yeastYarrowia lipolytica,de novolipid synthesis and accumulation are induced under conditions of nitrogen limitation (or a high carbon-to-nitrogen ratio). The regulatory pathway responsible for this induction has not been identified. Here we report that the SNF1 pathway plays a key role in the transition from the growth phase to the oleaginous phase inY. lipolytica. Strains with aY. lipolyticasnf1(Ylsnf1) deletion accumulated fatty acids constitutively at levels up to 2.6-fold higher than those of the wild type. When introduced into aY. lipolyticastrain engineered to produce omega-3 eicosapentaenoic acid (EPA),Ylsnf1deletion led to a 52% increase in EPA titers (7.6% of dry cell weight) over the control. Other components of theY. lipolyticaSNF1 pathway were also identified, and their function in limiting fatty acid accumulation is suggested by gene deletion analyses. Deletion of the gene encoding YlSnf4, YlGal83, or YlSak1 significantly increased lipid accumulation in both growth and oleaginous phases compared to the wild type. Furthermore, microarray and quantitative reverse transcription-PCR (qRT-PCR) analyses of theYlsnf1mutant identified significantly differentially expressed genes duringde novolipid synthesis and accumulation inY. lipolytica. Gene ontology analysis found that these genes were highly enriched with genes involved in lipid metabolism. This work presents a new role for Snf1/AMP-activated protein kinase (AMPK) pathways in lipid accumulation in this oleaginous yeast.

Differential expression of TNF-α, IL-6, and IGF-1 by graded mechanical stress in normal rat myocardium

2002 ◽  
Vol 282 (3) ◽  
pp. H926-H934 ◽  
Author(s):  
Emiliano A. Palmieri ◽  
Giulio Benincasa ◽  
Francesca Di Rella ◽  
Cosma Casaburi ◽  
Maria G. Monti ◽  
...  
Keyword(s):  
Time Course ◽  
De Novo ◽  
Mechanical Stretch ◽  
Progressive Increase ◽  
Compensatory Hypertrophy ◽  
Current Data ◽  
Rat Myocardium ◽  
Tnf Α ◽  
Normal Rat ◽  
Necrosis Factor

An isovolumic normal rat heart Langendorff model was used to examine the effects of moderate (15 mmHg) and severe (35 mmHg) mechanical stretch on the time course (from 0 to 60 min) of myocardial expression of tumor necrosis factor (TNF)-α, interleukin (IL)-6, and insulin-like growth factor (IGF)-1 and their cognate receptors. After 10 min of moderate stretch, TNF-α was de novo expressed, whereas constitutive IL-6 and IGF-1 levels were slightly upregulated; no further changes occurred up to 60 min. In comparison, severe stretch resulted in a higher and progressive increase in TNF-α, IL-6, and IGF-1 expression up to 20 min. After 20 min, whereas TNF-α expression further increased, IL-6 and IGF-1 levels progressively reduced to values lower than those observed under moderate stretch and in unstretched (5 mmHg) control myocardium (IL-6). Mechanical stretch did not significantly alter the expression of the cognate receptors. Indeed, the TNF-α receptor (p55) tended to be progressively upregulated under severe stretch over time. The current data provide the first demonstration that TNF-α, IL-6, and IGF-1 ligand-receptor systems are differentially expressed within the normal rat myocardium in response to graded mechanical stretch. Such findings may have potential implications with regard to compensatory hypertrophy and failure.

scholarly journals Enlarged Peroxisomes Are Present in Oleic Acid–grown Yarrowia lipolytica Overexpressing the PEX16 Gene Encoding an Intraperoxisomal Peripheral Membrane Peroxin

1997 ◽  
Vol 137 (6) ◽  
pp. 1265-1278 ◽  
Author(s):  
Gary A. Eitzen ◽  
Rachel K. Szilard ◽  
Richard A. Rachubinski
Keyword(s):  
Oleic Acid ◽  
Yarrowia Lipolytica ◽  
Consensus Sequence ◽  
Wild Type ◽  
Gene Encoding ◽  
Peroxisomal Membrane ◽  
Peripheral Protein ◽  
The Matrix ◽  
Peroxisomal Targeting ◽  
Targeting Signal

Pex mutants of the yeast Yarrowia lipolytica are defective in peroxisome assembly. The mutant strain pex16-1 lacks morphologically recognizable peroxisomes. Most peroxisomal proteins are mislocalized to a subcellular fraction enriched for cytosol in pex16 strains, but a subset of peroxisomal proteins is localized at, or near, wild-type levels to a fraction typically enriched for peroxisomes. The PEX16 gene was isolated by functional complementation of the pex16-1 strain and encodes a protein, Pex16p, of 391 amino acids (44,479 D). Pex16p has no known homologues. Pex16p is a peripheral protein located at the matrix face of the peroxisomal membrane. Substitution of the carboxylterminal tripeptide Ser-Thr-Leu, which is similar to the consensus sequence of peroxisomal targeting signal 1, does not affect targeting of Pex16p to peroxisomes. Pex16p is synthesized in wild-type cells grown in glucose-containing media, and its levels are modestly increased by growth of cells in oleic acid–containing medium. Overexpression of the PEX16 gene in oleic acid– grown Y. lipolytica leads to the appearance of a small number of enlarged peroxisomes, which contain the normal complement of peroxisomal proteins at levels approaching those of wild-type peroxisomes.

scholarly journals Repression of the pyr Operon in Lactobacillus plantarum Prevents Its Ability To Grow at Low Carbon Dioxide Levels

2005 ◽  
Vol 187 (6) ◽  
pp. 2093-2104 ◽  
Author(s):  
Hervé Nicoloff ◽  
Aram Elagöz ◽  
Florence Arsène-Ploetze ◽  
Benoît Kammerer ◽  
Jan Martinussen ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Lactobacillus Plantarum ◽  
De Novo ◽  
Site Directed Mutagenesis ◽  
Low Carbon ◽  
Wild Type ◽  
Carbamoyl Phosphate ◽  
Phosphoribosyl Pyrophosphate ◽  
Pyrimidine Nucleotides ◽  
Transcription Attenuation

ABSTRACT Carbamoyl phosphate is a precursor for both arginine and pyrimidine biosynthesis. In Lactobacillus plantarum, carbamoyl phosphate is synthesized from glutamine, ATP, and carbon dioxide by two sets of identified genes encoding carbamoyl phosphate synthase (CPS). The expression of the carAB operon (encoding CPS-A) responds to arginine availability, whereas pyrAaAb (encoding CPS-P) is part of the pyrR1BCAaAbDFE operon coding for the de novo pyrimidine pathway repressed by exogenous uracil. The pyr operon is regulated by transcription attenuation mediated by a trans-acting repressor that binds to the pyr mRNA attenuation site in response to intracellular UMP/phosphoribosyl pyrophosphate pools. Intracellular pyrimidine triphosphate nucleoside pools were lower in mutant FB335 (carAB deletion) harboring only CPS-P than in the wild-type strain harboring both CPS-A and CPS-P. Thus, CPS-P activity is the limiting step in pyrimidine synthesis. FB335 is unable to grow in the presence of uracil due to a lack of sufficient carbamoyl phosphate required for arginine biosynthesis. Forty independent spontaneous FB335-derived mutants that have lost regulation of the pyr operon were readily obtained by their ability to grow in the presence of uracil and absence of arginine; 26 harbored mutations in the pyrR1-pyrB loci. One was a prototroph with a deletion of both pyrR1 and the transcription attenuation site that resulted in large amounts of excreted pyrimidine nucleotides and increased intracellular UTP and CTP pools compared to wild-type levels. Low pyrimidine-independent expression of the pyr operon was obtained by antiterminator site-directed mutagenesis. The resulting AE1023 strain had reduced UTP and CTP pools and had the phenotype of a high-CO2-requiring auxotroph, since it was able to synthesize sufficient arginine and pyrimidines only in CO2-enriched air. Therefore, growth inhibition without CO2 enrichment may be due to low carbamoyl phosphate pools from lack of CPS activity.

Isolation of a chitinase overproducing mutant of Streptomyces peucetius defective in daunorubicin biosynthesis

2000 ◽  
Vol 46 (10) ◽  
pp. 956-960 ◽  
Author(s):  
Kuzhandhaivel S Vetrivel ◽  
Kuppamuthu Dharmalingam
Keyword(s):  
Biosynthetic Pathway ◽  
Time Course ◽  
Polyketide Synthase ◽  
Protein Profile ◽  
Restriction Enzymes ◽  
Wild Type ◽  
Anthracycline Antibiotic ◽  
Streptomyces Peucetius ◽  
Chitinase Production ◽  
Major Alteration

Streptomyces peucetius, producer of the antitumor anthracycline antibiotic daunorubicin, was mutagenized, and mutants defective in daunorubicin biosynthesis were screened. One mutant (SPVI), which failed to produce daunorubicin, was found to overproduce an extracellular chitinase. Time course analyses of chitinase production and of the extracellular protein profile showed that the increase in activity is due to increased synthesis of the enzyme protein. The production of chitinase in SPVI was repressed by glucose as in the case of wild-type S. peucetius. PFGE analysis of VspI restriction fragments of S. peucetius and SPVI showed that there was no major alteration in the mutant genome. The hybridization pattern of S. peucetius and SPVI genomic DNA digested with various restriction enzymes was identical when probed with dnrUVJI genes of the S. peucetius daunorubicin cluster and chiA of Streptomyces lividans 66. The possible step affected in the daunorubicin biosynthetic pathway could be a polyketide synthase, since aklanonic acid, the earliest detectable intermediate in the daunorubicin pathway, was not synthesized in SPVI.Key words: Streptomyces peucetius, chitinase, daunorubicin, NTG mutagenesis.

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