Search results for "Ornithine"

Evolution of arginine deiminase (ADI) pathway genes

2002

We have analyzed the evolution of the three genes encoding structural enzymes of the arginine deiminase (ADI) pathway, arginine deiminase (ADI), ornithine transcarbamoylase (OTC), and carbamate kinase (CK) in a wide range of organisms, including Archaea, Bacteria, and Eukarya. This catabolic route was probably present in the last common ancestor to all the domains of life. The results obtained indicate that these genes have undergone a complex evolutionary history, including horizontal transfer events, duplications, and losses. Therefore, these genes are not adequate to infer organismal relationships at deep branching levels, but they provide an insight into how catabolic genes evolved and …

Ornithine decarboxylase activity during chick embryo retina development:hydrocortisone effect

1987

Molecular analysis of a human liver mitochondrial ornithine transcarbamylase deficiency.

1990

The liver of a young girl which had been successfully transplanted was investigated at the ornithine transcarbamylase (OTC, EC 2.1.3.3) gene expression level. Northern blot hybridization using a human OTC cDNA probe showed a greater than 80% decrease in specific OTC mRNA although having the same molecular size as a normal control. OTC polypeptide was simultaneously synthesized with a normal molecular size but at a low level (20%) as shown by immunoblotting. The OTC enzyme from the deficient liver exhibited very little catalytic activity (7.2% as compared to the normal subject). These results may support several explanations of this disease such as mutation of the OTC gene promoter leading t…

Gliadin activates arginase pathway in RAW264.7 cells and in human monocytes

2014

AbstractCeliac disease (CD) is an autoimmune enteropathy triggered in susceptible individuals by the ingestion of gliadin-containing grains. Recent studies have demonstrated that macrophages play a key role in the pathogenesis of CD through the release of inflammatory mediators such as cytokines and nitric oxide (NO). Since arginine is the obliged substrate of iNOS (inducible nitric oxide synthase), the enzyme that produces large amount of NO, the aim of this work is to investigate arginine metabolic pathways in RAW264.7 murine macrophages after treatment with PT-gliadin (PTG) in the absence and in the presence of IFNγ. Our results demonstrate that, besides strengthening the IFNγ-dependent …

Improved scalable syntheses of mono- and bis-urethane derivatives of ornithine.

2001

In the search for a practical route to ornithine bisurethane derivatives useful for peptide synthesis, we elaborated the simple and efficient (86% yield) synthesis of N(epsilon)-tert-butoxycarbonyl-L-ornithine copper(II) complex (1). This served as substrate for obtaining N(epsilon)-tert-butoxycarbonyl-L-ornithine (2), N(alpha)-benzyloxycarbonyl-N(epsilon)-tert-butoxycarbonyl-L-ornithine (3) and N(alpha)-(9-fluorenyl)methoxycarbonyl-N(epsilon)-tert-butoxycarbonyl-L-ornithine (4). These were synthesized in 94-95% yields and with a purity above 99%.

Carbonic anhydrase inhibitor with topical NSAID therapy to manage cystoid macular edema in a case of gyrate atrophy

2017

Purpose Gyrate atrophy of the choroid and retina (GACR) is a rare chorioretinal dystrophy characterized by a deficiency of the enzyme ornithine aminotransferase, inherited in an autosomal recessive pattern. Case Report We report a case of a 17-year-old girl with GACR, for whom the level of serum ornithine had been reduced by an arginine-restricted diet. The patient was responsive to an association of topical nonsteroidal anti-inflammatory drugs (NSAIDs) and a carbonic anhydrase inhibitor (CAI) to reduce cystoid macular edema (CME). Conclusions The efficacy of topical NSAIDs and systemic CAI association indicates that the imbalance in the distribution of retinal pigment epithelium membrane-b…

Amino acids requirements of measles virus in HeLa cells.

1973

A low plating efficiency for measles virus was obtained when arginine, threonine and isoleucine were omitted from Eagle's basal medium and a stimulatory effect on the plaque production was produced by increasing the concentration up to 0.5 mm of arginine and glutamine. However, of all amino acids in Eagle's basal medium, only methionine was found to be essential for the synthesis of infectious progeny virus. Omission of any one of the other amino acids from the culture medium permitted limited virus production, but none whatever could be detected in the absence of mediummethionine. Moreover, when methionine was restored to infected cultures after 24 hours of deprivation, release of virus be…

Inhibition of arginase in rat and rabbit alveolar macrophages by Nω-hydroxy-D,L-indospicine, effects onL-arginine utilization by nitric oxide synthase

1997

1. Alveolar macrophages (AM phi) exhibit arginase activity and may, in addition, express an inducible form of nitric oxide (NO) synthase (iNOS). Both pathways may compete for the substrate. L-arginine. The present study tested whether two recently described potent inhibitors of liver arginase (N omega-hydroxy-D,L-indospicine and 4-hydroxyamidino-D,L-phenylalanine) might also inhibit arginase in AM phi and whether inhibition of arginase might affect L-arginine utilization by iNOS. 2. AM phi obtained by broncho-alveolar lavage of rat and rabbit isolated lungs were disseminated (2.5 or 3 x 10(6) cells per well) and allowed to adhere for 2 h. Thereafter, they were either used to study [3H]-L-ar…

Stimulation of root and somatic embryo production in Euconymus europaeus L. by an inhibitor of polyamine biosynthesis

1995

In vitro formation of roots and somatic embryos is obtained from cotyledon explants of a Spindle tree (Euonymus europaeus L.) cultured on two different media: a medium inducing callus formation and the production of roots, and a medium inducing callus formation, root and somatic embryo production. We studied the effects of α-difluoromethylornithine (DFMO), a specific, irreversible inhibitor of ornithine decarboxylase (ODC) on root and somatic embryo production, growth and titers of putrescine in Euonymus explants and explant-derived calli. Early changes in putrescine levels were detected in both cultures before the visible emergence of roots or somatic embryos. DFMO rapidly inhibited putres…

Polyamines and ripening of photoreceptor outer segments in chicken embryos.

1995

Abstract Polyamines and their related monoacetyl derivatives were studied in rod outer segment (ROS) and cone outer segment (COS) of photoreceptor cells from chick embryo retina during eye development (7th–18th days). Putrescine was found to be necessary, in the second phase of retinogenesis, to sustain both ROS and COS differentiation and, after acetylation, γ-aminobutyric acid synthesis. On the other hand, spermidine and even more spermine intervene in the third phase of development when photoreceptors mature. Moreover, the presence of N1-acetylspermidine already at the 7th day indicates that in the outer segment of photoreceptor cells too, as in the whole retina, putrescine synthesis com…