Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:4.1.1.17 (ornithine decarboxylase)
6,351 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The relationship between ornithine decarboxylase (L-ornithine carboxylyase, EC 4.1.1.17) activity and DNA synthetic activity was studied in mouse epidermis. Interfollicular epidermis and hair follicles were investigated separately. It was found that, in hair follicles, the variations of DNA replicative activity, which are reflected in the cyclic growth of hair, are paralleled by corresponding changes in ornithine decarboxylase activity. In both interfollicular epidermis and hair follicles, stimulation of DNA synthetic activity by plucking of hair induced a rapid and marked increase in ornithine decarboxylase activity. The relationship of steady-state and induced ornithine decarboxylase activity to DNA synthetic activity was compared in hair follicles and interfollicular epidermis. A correlation between the activity of this enzyme and DNA replication was found thereby in each of these tissues.
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PMID:Ornithine decarboxylase activity in relation to DNA synthesis in mouse interfollicular epidermis and hair follicles. 118 78

A rapid medium for the detection of lysine and ornithine decarboxylase and arginine dihydrolase activity of 439 strains of gram-negative, nonfermenting bacteria was evaluated and compared with Moeller decarboxylase medium. Results were obtained in 4 to 24 h using the rapid medium, whereas Moeller medium often required extended (3 to 7 days) incubation. There was 100% agreement in the lysine tests with both media and almost 100% agreement in the ornithine tests. There was 91% agreement in the arginine tests, with the significance of discrepant results discussed. The sensitivity, specificity, and quick results obtained by the rapid test make it a suitable substitute for Moeller medium for the identication of gram-negative, nonfermenting bacteria.
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PMID:Evaluation of the rapid decarboxylase and dihydrolase test for the differentiation of nonfermentative bacteria. 125 12

This article reviews the structural and functional changes which develop in the intestine and pancreas in response to a variety of stimuli and which characterise adaptive hyper- or hypo-plasia. It then discusses the principal physiological mechanisms controlling this adaptive growth. In the gut, these include luminal nutrition, endocrine, autocrine and paracrine hormonal influences, growth factors, enterotrophic components of pancreatico-biliary secretions, neural factors, changes in blood flow and mesenchyme-epithelial interactions. The cell biology of adaptive growth involves cell membrane receptors (first messengers) and a cascade of intracellular second messengers, the best studied of which is changes in polyamine metabolism and in related enzymes. The effects of ornithine decarboxylase (ODC) blockade with difluoromethyl ornithine (DFMO) and of diamine oxidase (DAO) blockade with aminoguanidine, are described. In general, DFMO inhibits or prevents adaptive hyperplasia while in the small bowel, aminoguanidine treatment induces 'supranormal' adaptation. However, both the gut and the pancreas transport 'exogenous' (ingested in food and circulating in the blood stream) polyamines across their apical and basolateral membranes. The influence of this exogenous polyamine transport on 'endogenous' (enzyme-regulated) intracellular polyamine concentrations, is largely unknown. Finally, the molecular biology of adaptive growth is described briefly--as illustrated by the use of a growth hormone transgenic model in which mice develop marked intestinal mucosal hyperplasia and increases in the relative abundance of insulin-like growth factor-I (IGF-I) mRNA in the intestine.
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PMID:Cellular and molecular basis of intestinal and pancreatic adaptation. 129 60

PTH-related peptide (PTHrP) is widely distributed in normal tissues, including the gut, and is considered a potential autocrine or paracrine regulator of cellular growth and differentiation. With this in mind, a human colonic cell line (LoVo) was used to study the effect of PTHrP on ornithine decarboxylase (ODC), because ODC is known to have profound effects on the growth and differentiation of many cell types via stimulation of synthesis of polyamines. cAMP also was measured, because this second messenger has been implicated in the regulation of ODC activity. Nearly confluent LoVo cells, grown in F-12 medium and 10% fetal bovine serum (FBS), were preincubated in 1% FBS for at least 5 h, and then PTHrP-(1-34) was added, and the incubation was continued for up to 6 h. Cell extracts were analyzed for ODC activity by measuring 14CO2 liberated from 14C-labeled ornithine, for cAMP by RIA, and for ODC mRNA by Northern analysis. PTHrP produced dose-related increases in both cAMP (2- to 3-fold) and ODC (3- to 5-fold), with a maximal effect at 0.1-1 microM and an ED50 of 1-10 nM. Comparison of the cAMP and ODC responses to PTHrP showed a strong correlation (r = 0.96; P less than 0.001). The effects of 1 microM PTHrP-(1-34) to increase cAMP and ODC were completely inhibited by 10-20 microM of the specific antagonist [Asn10,Leu11]PTHrP-(7-34). PTHrP-(1-34) did not stimulate ODC activity when cells were incubated without FBS. The stimulation of ODC activity by PTHrP-(1-34) was maximal at 2 h, a time at which an increase in ODC mRNA also was evident. PTH-(1-34) and forskolin also stimulated ODC activity, but PTHrP-(67-86) amide was ineffective. The results indicate that the N-terminal portion of the PTHrP molecule can stimulate ODC activity in a human colon cell line and that the effect is probably mediated by cAMP. The results are consistent with the idea that PTHrP may influence cell growth and differentiation in the gut via an effect on polyamine biosynthesis. Since LoVo cells also express PTHrP mRNA, this gastrointestinal cell line may serve as a useful model for studying autocrine regulation of gut cell growth and differentiation by PTHrP.
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PMID:Effects of parathyroid hormone-related peptide on adenosine 3',5'-monophosphate and ornithine decarboxylase in a human colonic cell line. 131 34

Vasoactive intestinal peptide (VIP) is a widely distributed neuropeptide that has been considered a potential regulator of cell growth and differentiation in various tissues, including the gut. To examine this idea, we used a human colon carcinoma cell line (LoVo) as a model system and measured ornithine decarboxylase (ODC), because this is the rate-limiting enzyme for the formation of polyamines, which are thought to be key factors in regulating cell growth. LoVo cells, grown to about 80% confluence in F-12 medium containing 10% fetal bovine serum, were preincubated for 5 h in low serum medium (1% fetal bovine serum in F-12), and ODC activity was determined by measuring 14CO2 liberated from 14C-labeled ornithine. VIP caused a dose-related biphasic change in ODC, with activity increased at 10 pM, maximal (5-fold increase) at 10 nM, and decreased toward basal at 100 nM to 1 microM. Incubation of cells for 6 days with VIP in low serum medium showed similar changes in cell numbers, with growth being increased by doses in the 1 pM to 100 nM range and decreased at higher doses (greater than or equal to 100 nM). Exposure of cells to 5 mM alpha-difluoromethylornithine blocked both the VIP-induced increase in cell number and the VIP-induced increase in ODC activity. Increased ODC mRNA was detected after 2 h of exposure to VIP, a time at which ODC activity peaked after treatment, and the increase in ODC mRNA caused by VIP was dose-dependent. In related experiments LoVo cells were found to have high affinity VIP receptors (Kd = 0.4 nM), as assessed by examination of [125I]VIP binding in the presence of varying concentrations of unlabeled VIP. Studies of intracellular cAMP revealed a dose-related increase in cAMP in response to VIP (ED50 = 11 pM), and the adenylate cyclase activator forskolin increased both ODC activity and ODC mRNA. The findings support the idea that LoVo cells have VIP receptors linked to cAMP which can stimulate cell growth at least in part by increasing ODC synthesis and activity, thereby altering the production of polyamines. The decreased growth and ODC activity observed with high doses of VIP may involve a second messenger other than cAMP.
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PMID:Effects of vasoactive intestinal peptide on adenosine 3',5'-monophosphate, ornithine decarboxylase, and cell growth in a human colon cell line. 132 53

A study was made of the biosynthesis by Anabaena flos-aquae of the tropane-related alkaloid anatoxin-a. Evidence is presented that the toxin arises from ornithine via putrescine (1,4-diaminobutane) and that ornithine decarboxylase (EC 4.1.1.17) is involved. An ornithine decarboxylase preparation, with optimal activity at pH 8, was obtained from Anabaena flos-aquae and partially purified by gel-filtration chromatography on DEAE-cellulose. One major and one minor peak of enzymic activity were obtained with Km values of 1.25 and 2.5 mM, respectively. Plasmid DNA (10 Kb; Mr 6.5 x 10(6] was detected in the toxic strain of Anabaena flos-aquae but not in a non-toxic strain. DNA from the toxin-producing strain of Anabaena flos-aquae transforms the non-toxic into a toxic strain.
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PMID:Biosynthesis of the tropane-related cyanobacterial toxin anatoxin-a: role of ornithine decarboxylase. 136 27

The genus name Morganella was established within the family Enterobacteriaceae in 1978. Morganella morganii is the only species described thus far within this genus, and the name M. morganii has been accepted by usage in the scientific community for strains previously known as Proteus morganii. M. morganii isolates differ in their abilities to ferment trehalose and exhibit variable lysine and ornithine decarboxylase patterns, emphasizing the phenotypic heterogeneity within this species. Previous genetic studies failed to reveal separate entities within the genus Morganella. We observed some trehalose-fermenting strains with different lysine and ornithine decarboxylase patterns. Two strains were lysine and ornithine positive, 3 were lysine positive and ornithine negative, and 29 were lysine negative and ornithine positive. These strains and 25 non-trehalose-fermenting strains with different lysine and ornithine decarboxylase patterns were investigated. DNA-DNA hybridization studies and phenotypic characterizations revealed that M. morganii can be separated into three DNA relatedness groups and seven biogroups. Strains from DNA relatedness group 1 were trehalose negative, and strains from DNA relatedness groups 2 and 3 were trehalose positive. One biogroup from DNA relatedness group 2 was phenotypically indistinguishable from DNA relatedness group 3. On the basis of these studies, we propose that M. morganii be subdivided into M. morganii subsp. morganii (type strain ATCC 25830) containing biogroups A, B, C, and D (DNA relatedness group 1) and M. morganii subsp. sibonii (type strain 8103-85; = ATCC 49948) containing biogroups E, F, and G (DNA relatedness groups 2 and 3).
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PMID:Recognition of Morganella subspecies, with proposal of Morganella morganii subsp. morganii subsp. nov. and Morganella morganii subsp. sibonii subsp. nov. 139 Jan 12

Ornithine decarboxylase may be a useful biomarker for risk of neoplasia in colorectal tissues. Investigators have reported enzyme activities varying by as much as 10- to 20-fold using variations of the usual 14CO2 release assay. We have examined the effect of different methodologic factors on calculated ornithine decarboxylase activity. Major effects on the assay result (greater than 20% change) were produced by: (1) use of Tris vs. phosphate buffer, the former yielding 1.5- to 4-fold greater activity; (2) protein content of the reaction mixture with significant error if less than 50 micrograms; (3) use of alpha-difluoro-methylornithine-inhibited blank versus buffer-only blank. Other changes in assay conditions, including addition of sucrose, detergent, protease inhibitors, specific activity of 14C-ornithine, the nature of the trapping agent used, and incorporation of a sonication step, did not have a significant effect on ODC quantification (less than or equal to 20%). Thus, seemingly minor variations in assay conditions can greatly affect the results, which may provide a partial explanation for the variability of ODC activities reported in the literature. Strict quality control measures are mandatory in the interpretation of clinical observations utilizing this marker as an endpoint.
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PMID:Ornithine decarboxylase assay in human colorectal mucosa. Methodologic issues of importance to quality control. 139 10

Ornithine decarboxylase (ODC), a key enzyme in polyamine biosynthesis, is important in development and regeneration. We hypothesize that aminoglycoside inhibition of ODC mediates developmental hypersensitivity to aminoglycoside ototoxicity. Kanamycin effects on ODC activity (decarboxylation of ornithine) in vitro were determined in the postmitochondrial fraction of cochlear and renal homogenates from 11-day-old rats. Kanamycin inhibited cochlear and renal ODC by an uncompetitive mechanism. For the cochlear enzyme, the inhibitor constant (Ki) for kanamycin was 99 +/- 25 mumol/L; for the renal enzyme, the Ki = 1.5 +/- 0.1 mmol/L. In vivo effects of kanamycin on cochlear, renal, brain ODC activity were determined in rats treated with kanamycin (400 mg/kg/day, intramuscularly) or saline during postnatal days 11 through 20, the hypersensitive period for ototoxicity. Rats were killed on postnatal days 12, 14, 16, and 20 and ODC was assayed. Kanamycin significantly inhibited ODC in the lateral wall-organ of Corti and kidney (ANOVA alpha = 0.05), but had no effect on cochlear nerve and no consistent inhibitory effect in the brain. These results suggest that ODC is a potential target of kanamycin in susceptible tissues and may be a contributing factor in developmental sensitivity to the drug by inhibiting repair and developmental processes mediated by ODC.
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PMID:Kanamycin inhibits cochlear-renal ODC in neonatal rats. 143 81

Mongolian gerbils were anesthetized with halothane and forebrain ischemia was induced by occluding both common carotid arteries. After 2, 4, 6, 8, or 10 min of vascular occlusion clips were removed and animals allowed to recover for 8 or 24 h. At the end of the experiments animals were reanesthetized and their brains frozen in situ. Tissue samples were taken from the cerebral cortex, striatum, hippocampus, and thalamus for determination of ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (SAMDC) activity by measurement of the release of 14CO2 from [14C]ornithine and S-[14C]adenosylmethionine, respectively. A transient increase in ODC activity was found after 8 h of recirculation following cerebral ischemia in all brain structures studied. ODC activity was significantly increased after 8 h of recirculation in the hippocampus of animals subjected to 4 min of ischemia, in the cortex and striatum after 6 min of ischemia, and in the thalamus after 8 min of vascular occlusion. ODC activity had already reached a plateau in the hippocampus after 4 min of vascular occlusion and in the cortex, striatum, and thalamus after 8 min, since there is no further increase in activity even after 10 min of ischemia. After cerebral ischemia and 24 h of recirculation ODC activity returned to control levels throughout the forebrain regardless of the duration of ischemia. SAMDC activity was significantly reduced after 8 h of recirculation following 4 to 10 min of ischemia in the cortex and 8 min of ischemia in the striatum.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Activity of ornithine decarboxylase and S-adenosylmethionine decarboxylase in transient cerebral ischemia: relationship to the duration of vascular occlusion. 149 93


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