ω-Hydroxylation of epoxy- and hydroxy-fatty acids by CYP94AI: possible involvement in plant defence

2000 ◽  
Vol 28 (6) ◽  
pp. 867-870 ◽  
Author(s):  
F. Pinot ◽  
M. Skrabs ◽  
V. Compagnon ◽  
J.-P. Salaun ◽  
I. Benveniste ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Fatty Acid ◽  
Plant Defence ◽  
Dihydroxystearic Acid ◽  
Racemic Mixture ◽  
Minor Role ◽  
Fatty Acid Derivatives ◽  
A Minor ◽  
Plant Pathogen Interactions ◽  
Epoxystearic Acid

The C18 fatty acid derivatives 9,10-epoxystearic acid and 9,10-dihydroxystearic acid were hydroxylated on the terminal methyl by microsomes of yeast expressing CYP94A1 cloned from Vicia sativa. The reactions did not occur in incubations of microsomes from yeast transformed with a void plasmid or in the absence of NADPH. After incubation of a synthetic racemic mixture of 9,10-epoxystearic acid, the chirality of the residual epoxide was shifted to 66:34 in favour of the 9S,10R enantiomer. Both the 9S, 10R and 9R, 10S enantiomers were incubated separately. We determined respective Km and Vmax values of 1.2±0.1 μM and 19.2±0.3 nmol/min per nmol of cytochrome P450 for the 9R, 10S enantiomer and of 5.9±0.1 μM and 20.2±1.0 nmol/min per nmol of cytochrome P450 for the 9S, 10R enantiomer. This demonstrated that CYP94A1 is enantioselective for the 9R, 10S, which is preferentially formed in V. sativa microsomes. Cutin analysis of V. sativa seedlings revealed that it is mainly constituted of derivatives of palmitic acid, a C16 fatty acid. Our results suggest that CYP94A1 might play a minor role in cutin synthesis and could be involved in plant defence. Indeed, 18-hydroxy-9,10-epoxystearic acid and 9,10,18-trihydroxystearic acid have been described as potential messengers in plant-pathogen interactions.

scholarly journals Production in vitro by the cytochrome P450 CYP94A1 of major C18 cutin monomers and potential messengers in plant–pathogen interactions: enantioselectivity studies

1999 ◽  
Vol 342 (1) ◽  
pp. 27-32 ◽  
Author(s):  
Franck PINOT ◽  
Irène BENVENISTE ◽  
Jean-Pierre SALAüN ◽  
Olivier LOREAU ◽  
Jean-Pierre NOËL ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Oleic Acid ◽  
Plant Pathogen ◽  
Dihydroxystearic Acid ◽  
Racemic Mixture ◽  
Vicia Sativa ◽  
Common Precursor ◽  
Plant Pathogen Interactions ◽  
Epoxystearic Acid

The major C18 cutin monomers are 18-hydroxy-9,10-epoxystearic and 9,10,18-trihydroxystearic acids. These compounds are also known messengers in plant-pathogen interactions. We have previously shown that their common precursor 9,10-epoxystearic acid was formed by the epoxidation of oleic acid in Vicia sativa microsomes (Pinot, Salaün, Bosch, Lesot, Mioskowski and Durst (1992) Biochem. Biophys. Res. Commun. 184, 183-193). Here we determine the chirality of the epoxide produced as (9R,10S) and (9S,10R) in the ratio 90:10 respectively. We further show that microsomes from yeast expressing the cytochrome P450 CYP94A1 are capable of hydroxylating the methyl terminus of 9,10-epoxystearic and 9,10-dihydroxystearic acids in the presence of NADPH to form the corresponding 18-hydroxy derivatives. The reactions were not catalysed by microsomes from yeast transformed with a void plasmid or in absence of NADPH. After incubation of a synthetic racemic mixture of 9,10-epoxystearic acid with microsomes of yeast expressing CYP94A1, the chirality of the residual epoxide was shifted to 66:34 in favour of the (9S,10R) enantiomer. Both enantiomers were incubated separately and Vmax/Km values of 16 and 3.42 ml/min per nmol of P450 for (9R,10S) and (9S,10R) respectively were determined, demonstrating that CYP94A1 is enantioselective for the (9R,10S) enantiomer, which is preferentially formed in V. sativa microsomes. Compared with the epoxide, the diol 9,10-dihydroxystearic acid was a much poorer substrate for the ω-hydroxylase, with a measured Vmax/Km of 0.33 ml/min per nmol of P450. Our results indicate that the activity of CYP94A1 is strongly influenced by the stereochemistry of the 9,10-epoxide and the nature of substituents on carbons 9 and 10, with Vmax/Km values for epoxide ≫ oleic acid > diol.

PHOTOSYNTHETIC CHARACTERIZATION OF A MUTANT OF NANNOCHLOROPSIS DEFICIENT IN THE SYNTHESIS OF EICOSAPENTAENOIC ACID

1998 ◽  
Vol 46 (2) ◽  
pp. 101-108 ◽  
Author(s):  
Assaf Sukenik ◽  
Jane Schneider C. ◽  
Paul Roessler G. ◽  
Alexander Livne ◽  
Tamar Berner ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Eicosapentaenoic Acid ◽  
Photosynthetic Apparatus ◽  
Photosynthetic Electron Transport ◽  
Photosynthetic Performance ◽  
Minor Role ◽  
Wild Type ◽  
Higher Temperature ◽  
A Minor

Photosynthetic performance of an eicosapentaenoic acid (EPA; 20:5ω3) deficient mutant of the eustigmatophyte Nannochloropsis sp. was compared to the wild type (Wt) strain in order to evaluate the effect of fatty acid composition on the function of the photosynthetic apparatus. Cellular photosynthetic capacity and the cellular pool of pigments and of reaction centers were reduced in the mutant concomitant with a reduction in the amount of thylakoid membranes and their volume-specific density. Despite the changes observed in photosynthetic activity, the fluorescence properties of the mutant were virtually the same as those of the wild type, although the phase transition of thylakoid membrane was recorded at higher temperature in the mutant than in the Wt. The results suggest that the change in one double bond in a very long chain fatty acid of the thylakoid lipids plays a minor role in regulating photosynthetic electron transport, but that the mutation modified the ability of the mutant to acclimate to low-irradiance conditions.

scholarly journals Cloning, Functional Expression, and Characterization of CYP709C1, the First Sub-terminal Hydroxylase of Long Chain Fatty Acid in Plants

2005 ◽  
Vol 280 (43) ◽  
pp. 35881-35889 ◽  
Author(s):  
Sylvie Kandel ◽  
Marc Morant ◽  
Irène Benveniste ◽  
Elizabeth Blée ◽  
Danièle Werck-Reichhart ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Cytochrome P450 ◽  
Fatty Acid ◽  
Plant Defense ◽  
Functional Expression ◽  
Transcriptional Level ◽  
Wheat Seedlings ◽  
Hydroxylated Fatty Acids ◽  
Engineered Yeast ◽  
Epoxystearic Acid

We cloned and characterized CYP709C1, a new plant cytochrome P450 belonging to the P450 family, that so far has no identified function except for clustering with a fatty acid metabolizing clade of P450 enzymes. We showed here that CYP709C1 is capable of hydroxylating fatty acids at the ω-1 and ω-2 positions. This work was performed after recoding and heterologous expression of a full-length cDNA isolated from a wheat cDNA library in an engineered yeast strain. Investigation on substrate specificity indicates that CYP709C1 metabolizes different fatty acids varying in their chain length (C12 to C18) and unsaturation. CYP709C1 is the first identified plant cytochrome P450 that can catalyze sub-terminal hydroxylation of C18 fatty acids. cis-9,10-Epoxystearic acid is metabolized with the highest efficiency, i.e. Km(app) of 8 μm and Vmax(app) of 328 nmol/min/nmol P450. This, together with the fact that wheat possesses a microsomal peroxygenase able to synthesize this compound from oleic acid, strongly suggests that it is a physiological substrate. Hydroxylated fatty acids are implicated in plant defense events. We postulated that CYP709C1 could be involved in plant defense by producing such compounds. This receives support from the observation that (i) sub-terminal hydroxylation of 9,10-epoxystearic acid is induced (15-fold after 3 h) in microsomes of wheat seedlings treated with the stress hormone methyl jasmonate and (ii) CYP709C1 is enhanced at the transcriptional level by this treatment. CYP709C1 transcript also accumulated after treatment with a combination of the safener naphthalic acid anhydride and phenobarbital. This indicates a possible detoxifying function for CYP709C1 that we discussed.

Confirmation That Cytochrome P450 2C8 (CYP2C8) Plays a Minor Role in (S)-(+)- and (R)-(-)-Ibuprofen Hydroxylation in Vitro

2008 ◽  
Vol 36 (12) ◽  
pp. 2513-2522 ◽  
Author(s):  
Shu-Ying Chang ◽  
Wenying Li ◽  
Sarah C. Traeger ◽  
Bei Wang ◽  
Donghui Cui ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Minor Role ◽  
Cytochrome P450 2C8 ◽  
A Minor

Acylcarnitine accumulation does not correlate with reperfusion recovery in palmitate-perfused rat hearts

1995 ◽  
Vol 268 (6) ◽  
pp. H2505-H2512 ◽  
Author(s):  
M. C. Madden ◽  
P. E. Wolkowicz ◽  
G. M. Pohost ◽  
J. B. McMillin ◽  
M. M. Pike
Keyword(s):  
Fatty Acid ◽  
Chain Fatty Acid ◽  
Minor Role ◽  
Long Chain Fatty Acid ◽  
Exogenous Substrate ◽  
Rat Hearts ◽  
Cpt I ◽  
A Minor ◽  
Perfused Hearts ◽  
Long Chain

Carnitine palmitoyltransferase-I (CPT-I) inhibitors improve postischemic myocardial function either by decreasing muscle long-chain acylcarnitines (LCAC) during ischemia or by increasing oxidation of alternate substrates such as glucose during reperfusion. These possibilities were evaluated using oxfenicine, a CPT-I inhibitor, and alternate substrates that bypass carnitine-dependent metabolism. Isolated rat hearts subjected to 20 min of ischemia followed by 40 min of reperfusion with 1.8 mM palmitate as exogenous substrate recovered little function during reperfusion. Hearts made ischemic and reperfused with palmitate and 2.4 mM hexanoate as exogenous substrates had significantly improved reperfusion function compared to palmitate-perfused hearts. Addition of 2 mM oxfenicine to palmitate-hexanoate-perfused hearts gave an additional small improvement in reperfusion function. At the end of ischemia, the LCAC content of hearts perfused with palmitate or hexanoate and palmitate was identical. Palmitate-, hexanoate, and oxfenicine-perfused hearts had significantly decreased LCAC content at the end of ischemia compared with hexanoate-palmitate-perfused hearts. Therefore, depressed reperfusion function in long-chain fatty acid-perfused hearts can be ameliorated by alternate substrates, including medium-chain fatty acids. LCAC accumulation during ischemia apparently plays only a minor role in the postischemic dysfunction of long-chain fatty acid-perfused hearts.

The Effect of Path Length and Display Size on Memory for Spatial Information

2012 ◽  
Vol 59 (3) ◽  
pp. 147-152 ◽  
Author(s):  
Katherine Guérard ◽  
Sébastien Tremblay
Keyword(s):  
Path Length ◽  
Potential Role ◽  
Spatial Information ◽  
Recall Performance ◽  
Minor Role ◽  
Length Effect ◽  
Serial Memory ◽  
Fixed Reference ◽  
A Minor

In serial memory for spatial information, some studies showed that recall performance suffers when the distance between successive locations increases relatively to the size of the display in which they are presented (the path length effect; e.g., Parmentier et al., 2005) but not when distance is increased by enlarging the size of the display (e.g., Smyth & Scholey, 1994). In the present study, we examined the effect of varying the absolute and relative distance between to-be-remembered items on memory for spatial information. We manipulated path length using small (15″) and large (64″) screens within the same design. In two experiments, we showed that distance was disruptive mainly when it is varied relatively to a fixed reference frame, though increasing the size of the display also had a small deleterious effect on recall. The insertion of a retention interval did not influence these effects, suggesting that rehearsal plays a minor role in mediating the effects of distance on serial spatial memory. We discuss the potential role of perceptual organization in light of the pattern of results.

Use of Different Tissue Thromboplastins in the Control of Anticoagulant-Therapy

1958 ◽  
Vol 02 (05/06) ◽  
pp. 462-480 ◽  
Author(s):  
Marc Verstraete ◽  
Patricia A. Clark ◽  
Irving S. Wright
Keyword(s):  
Prothrombin Time ◽  
Anticoagulant Therapy ◽  
Factor Vii ◽  
Rabbit Brain ◽  
Minor Role ◽  
Rabbit Lung ◽  
Coagulation Mechanism ◽  
Time Test ◽  
The One ◽  
A Minor

SummaryAn analysis of the results of prothrombin time tests with different types of thromboplastins sheds some light on the problem why the administration of coumarin is difficult to standardize in different centers. Our present ideas on the subject, based on experimental data may be summarized as follows.Several factors of the clotting mechanism are influenced by coumarin derivatives. The action of some of these factors is by-passed in the 1-stage prothrombin time test. The decrease of the prothrombin and factor VII levels may be evaluated in the 1-stage prothrombin time determination (Quick-test). The prolongation of the prothrombin times are, however, predominantly due to the decrease of factor VII activity, the prothrombin content remaining around 50 per cent of normal during an adequate anticoagulant therapy. It is unlikely that this degree of depression of prothrombin is of major significance in interfering with the coagulation mechanism in the protection against thromboembolism. It may, however, play a minor role, which has yet to be evaluated quantitatively. An exact evaluation of factor VII is, therefore, important for the guidance of anticoagulant therapy and the method of choice is the one which is most sensitive to changes in factor VII concentration. The 1-stage prothrombin time test with a rabbit lung thromboplastin seems the most suitable method because rabbit brain preparations exhibit a factor VII-like activity that is not present in rabbit lung preparations.

Produktivkraft als Versprechen

2016 ◽  
Vol 46 (185) ◽  
pp. 621-638 ◽  
Author(s):  
Christian Siefkes
Keyword(s):  
Private Consumption ◽  
Minor Role ◽  
Progressive Reduction ◽  
Internal Forces ◽  
A Minor

The ‘Fragment on Machines’ from Marx’s Grundrisse is often cited as an argument that the internal forces of capitalism will lead to its doom. But the argument that the progressive reduction of labor must doom capitalism lacks a proper foundation, as a comparison with the ‘Schemes of Reproduction’ given in Capital II shows. The latter, however, aren’t fully convincing either. In reality, more depends on the private consumption of capitalists than either model recognizes. Ultimately, most can be made of the ‘Fragment on Machines’ by reading it not as an exposure of capitalism’s internal contractions, but as a discussion of a possible communist future where labor (or work) will play but a minor role.

Effects of Myo-inositol Alone and in Combination with Seleno-Lmethionine on Cadmium-Induced Testicular Damage in Mice

2019 ◽  
Vol 12 (4) ◽  
pp. 311-323 ◽  
Author(s):  
Salvatore Benvenga ◽  
Antonio Micali ◽  
Giovanni Pallio ◽  
Roberto Vita ◽  
Consuelo Malta ◽  
...  
Keyword(s):  
Structural Changes ◽  
Natural Antioxidants ◽  
Minor Role ◽  
Positive Role ◽  
Testosterone Levels ◽  
Tnf Α ◽  
Testicular Lesions ◽  
A Minor ◽  
Immunohistochemical Analyses

Background: Cadmium (Cd) impairs gametogenesis and damages the blood-testis barrier. Objective: As the primary mechanism of Cd-induced damage is oxidative stress, the effects of two natural antioxidants, myo-inositol (MI) and seleno-L-methionine (Se), were evaluated in mice testes. Methods: Eighty-four male C57 BL/6J mice were divided into twelve groups: 0.9% NaCl (vehicle; 1 ml/kg/day i.p.); Se (0.2 mg/kg/day per os); Se (0.4 mg/kg/day per os); MI (360 mg/kg/day per os); MI plus Se (0.2 mg/kg/day); MI plus Se (0.4 mg/kg/day); CdCl2 (2 mg/kg/day i.p.) plus vehicle; CdCl2 plus MI; CdCl2 plus Se (0.2 mg/kg/day); CdCl2 plus Se (0.4 mg/kg/day); CdCl2 plus MI plus Se (0.2 mg/kg/day); and CdCl2 plus MI plus Se (0.4 mg/kg/day). After 14 days, testes were processed for biochemical, structural and immunohistochemical analyses. Results: CdCl2 increased iNOS and TNF-α expression and Malondialdehyde (MDA) levels, lowered glutathione (GSH) and testosterone, induced testicular lesions, and almost eliminated claudin-11 immunoreactivity. Se administration at 0.2 or 0.4 mg/kg significantly reduced iNOS and TNF-α expression, maintained GSH, MDA and testosterone levels, structural changes and low claudin-11 immunoreactivity. MI alone or associated with Se at 0.2 or 0.4 mg/kg significantly reduced iNOS and TNF-α expression and MDA levels, increased GSH and testosterone levels, ameliorated structural organization and increased claudin-11 patches number. Conclusion: We demonstrated a protective effect of MI, a minor role of Se and an evident positive role of the association between MI and Se on Cd-induced damages of the testis. MI alone or associated with Se might protect testes in subjects exposed to toxicants, at least to those with behavior similar to Cd.

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