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)

To study the role of the polyamines putrescine, spermidine and spermine and of the enzymes controlling their synthesis (ornithine decarboxylase; ODC) and degradation (diamine oxidase; DAO) along the villus:crypt axis at the crucial early stage of the ileal adaptive response to jejunectomy, we measured polyamine concentrations and the activities of ODC, DAO and alkaline phosphatase (a marker of enterocyte maturity) in epithelial cells isolated by the Weiser technique from villus tips, mid villi, lower villi and crypts 4 days after surgery in transected control (TRC) and jejunectomised rats untreated or given the specific ODC blocker, alpha-difluoromethyl ornithine (DFMO, 2% in drinking water beginning 3 days before surgery). In the TRCs, there was a diminishing villus tip-to-crypt gradient not only in alkaline phosphatase but also in ODC and DAO activities. After jejunectomy, there were up to 93% increases in mean enterocyte ODC activity when compared with the corresponding cell fractions from the TRCs, but in both the control and jejunectomised rats, DFMO treatment markedly inhibited ODC activity (p less than 0.05-0.01) and reduced spermidine and particularly putrescine concentrations (p less than 0.005-0.001) in all four cell fractions. Only 4 days post-operation, jejunectomy stimulated a significant increase in ileal wet weight but DFMO treatment completely prevented this adaptive response and significantly reduced segmental intestinal weight (mg/cm) in the TRCs. These results (i) extend our knowledge of polyamines and related enzymes along the villus:crypt gradient in the normal intestine, (ii) provides the first data on these variables after resection, and (iii) lend further support to the hypothesis that changes in enterocyte ODC activity and in putrescine and spermidine concentrations play an important role in initiating the ileal adaptive response to proximal small bowel resection in the rat.
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PMID:Role of polyamines in the early adaptive response to jejunectomy in the rat: effect of DFMO on the ileal villus:crypt axis. 212 63

Ornithine decarboxylase (ODC; EC 4.1.1.17), transglutaminase (EC 2.3.2.13), diamine oxidase (DAO; EC 1.4.3.6) and total di- and poly-amines were studied in rat liver and kidney cortex throughout pregnancy. In liver, ODC activity exhibited two major peaks (4.5-5 times the control activities) on days 15 and 17. Also putrescine and spermidine increased biphasically (3-4-fold), but no variation in spermine content was observed. Transglutaminase activity showed slight variations only near the end of gestation. In kidney, ODC activity did not fluctuate significantly during pregnancy, whereas both transglutaminase activity and putrescine content showed three major increases, in very early, middle and late pregnancy. No significant variations in spermidine and spermine were observed. In both organs, DAO activity, very low or undetectable until day 10, dramatically increased (10- and 20-fold in kidney and liver respectively) in the second half of pregnancy, reaching maxima on days 16-17 and 19. The results obtained for transglutaminase, ODC and total di- and poly-amines are interpreted on the basis of hyperplastic and hypertrophic events in the liver and kidney respectively. The behaviour of DAO suggests that the enzyme plays an important role in the control of intracellular diamine concentration.
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PMID:Ornithine decarboxylase, transglutaminase, diamine oxidase and total diamines and polyamines in maternal liver and kidney throughout rat pregnancy. 287 83

The cellular mechanisms controlling adaptive intestinal mucosal hypo- and hyperplasia are poorly understood but changes in tissue polyamine levels and in the activity of the key enzymes controlling their synthesis (ornithine decarboxylase: ODC) and degradation (diamine oxidase: DAO) have been implicated. Therefore, in two models of adaptive mucosal hyperplasia (pancreatico-biliary diversion, PBD, achieved by surgically transposing the jejunum to lie between pylorus and ampulla of Vater, and 90% small bowel resection, SBR-both studied 8 weeks after surgery) and in one model of hypoplasia (8 days total parenteral nutrition) we measured indices of mucosal mass (wet weight, protein and DNA per 10-cm intestine), the growth-associated polyamines (putrescine, spermidine and spermine per 10-cm intestine and per mg DNA) and DAO activity in the duodenum, five 10-cm segments of jejunum, five 10-cm segments of ileum and in the colon, and compared the results with those found in transected or unoperated controls. The results for the indices of mucosal mass confirmed that TPN led to a modest degree of small bowel mucosal hypoplasia whilst PBD, and particularly 90% SBR, stimulated marked adaptive hyperplasia. There were corresponding changes in the amounts of putrescine and spermidine (but not of spermine)-not only when the results were expressed per unit length but also when calculated per mg mucosal DNA and in the ratio of spermidine:spermine. There was an increasing proximal-to-distal gradient in mucosal DAO per unit length intestine in all experimental groups but when the results were expressed per mg DNA, the ileal DAO levels were significantly reduced in the PBD and resection groups, when compared with the controls. These data support the hypothesis that polyamines play a major, and perhaps a controlling, role in regulating adaptive intestinal mucosal growth.
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PMID:Role of polyamines in intestinal adaptation in the rat. 312 40

The evidence for and against an enteropancreatic trophic axis is reviewed. Luminal nutrition is essential for the maintenance of normal intestinal mucosal, and exocrine pancreatic, structure and function. Exclusion of luminal nutrition leads to mucosal hypoplasia and hypofunction with similar changes in the pancreas. The trophic effect of luminal nutrition may be mediated through the release of regulatory peptides with endocrine or paracrine effects. Enteroglucagon is the strongest candidate for the role of 'enterotrophin' while cholecystokinin (CCK) markedly influences pancreatic growth. Thus, CCK not only stimulates exocrine pancreatic secretion but makes acinar cells divide and the pancreas grow. The cellular mechanisms whereby trophic peptides influence normal and adaptive growth are also discussed with emphasis on polyamines (putrescine, spermidine and spermine) and the key enzymes controlling their synthesis (ornithine decarboxylase; ODC) and degradation (diamine oxidase; DAO). When polyamine synthesis is blocked with the ODC inhibitor, difluoromethyl ornithine (DFMO), the adaptive intestinal hyperplasia of pancreatico-biliary diversion is either inhibited or completely prevented. A proposed sequence of events might be as follows: luminal nutrients, particularly long-chain fats, reach the ileum and colon and stimulate increased enteroglucagon release. Enteroglucagon binds to cell receptors and triggers an intracellular cascade involving ODC and the polyamines, which, in turn, stimulate RNA polymerase, DNA, RNA and protein synthesis, cell division, and adaptive tissue growth.
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PMID:Hormones and polyamines in intestinal and pancreatic adaptation. 392 43

The evidence for an enteropancreatic trophic axis is reviewed. Luminal nutrition is essential for the maintenance of normal intestinal mucosal, as well as exocrine pancreatic structure and function. Exclusion of luminal nutrition leads to mucosal hypoplasia and hypofunction with similar changes in the pancreas. The trophic effect of luminal nutrition may be mediated through the release of regulatory peptides with endocrine or paracrine effects. Enteroglucagon is the strongest candidate for the role of "enterotrophin" while cholecystokinin (CCK) markedly influences pancreatic growth. Thus, CCK not only stimulates exocrine pancreatic secretion but makes acinar cells divide and the pancreas grow. The cellular mechanisms whereby trophic peptides influence normal and adaptive growth are also discussed with emphasis on polyamines (putrescine, spermidine and spermine) and the key enzymes controlling their synthesis (ornithine decarboxylase [ODC]) and degradation (diamine oxidase [DAO]). When polyamine synthesis is blocked with the ODC inhibitor difluoromethyl ornithine (DFMO), the adaptive intestinal hyperplasia of pancreaticobiliary diversion is either inhibited or completely prevented. A proposed sequence of events might be: luminal nutrients, particularly long chain fat, reach the ileum and colon and stimulate increased enteroglucagon release. Enteroglucagon binds to cell receptors and triggers an intracellular cascade involving ODC and the polyamines which, in turn, stimulate RNA polymerase, DNA, RNA and protein synthesis, cell division and adaptive tissue growth.
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PMID:[Potential adaptation of the gastrointestinal system. Existence of an enteropancreatic trophic axis, the role of hormones and polyamines]. 393 Dec 14

The effect of methyl jasmonate (MJ) on de novo shoot formation and polyamine metabolism was investigated in thin layer explants of tobacco (Nicotiana tabacum L. cv. Samsun). A relatively low concentration of MJ (0.1 microM) enhanced explant fresh weight, but had no effect on the final number of shoots per explant while higher concentrations (1 and 10 microM) significantly inhibited organogenesis. The histological study revealed that, with increasing concentrations of MJ, the formation of meristemoids and shoot domes declined and the incidence of cell hypertrophy increased. In explants cultured with 0.1, 1 or 10 microM MJ, the endogenous levels of free putrescine, spermidine and spermine generally declined compared with controls, after 7 and 15 d. Perchloric acid-soluble conjugated polyamines accumulated dramatically during culture, but much more so in the presence of MJ than in controls. Acid-insoluble conjugated spermidine alone increased in response to the elicitor. Activities of the putrescine biosynthetic enzymes arginine decarboxylase (ADC, EC 4.1.1.19) and ornithine decarboxylase (ODC, EC 4.1.1.17) in the soluble fraction of MJ-treated explants displayed up to 3-fold increases relative to control explants. However, the most relevant increases in these enzyme activities occurred in the particulate fraction. The activity of S:-adenosylmethionine decarboxylase (SAMDC, EC 4.1.1.21), an enzyme involved in spermidine and spermine biosynthesis, was also stimulated by exposure to MJ. Northern analyses revealed MJ-induced, generally dose-dependent, increases in the mRNA levels of all three enzymes. Diamine oxidase (DAO, EC 1.4.3.6) activity was stimulated by MJ mainly in the cell wall fraction. The upregulation of polyamine metabolism is discussed in relation to the morphogenic behaviour of MJ-treated explants.
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PMID:Methyl jasmonate upregulates biosynthetic gene expression, oxidation and conjugation of polyamines, and inhibits shoot formation in tobacco thin layers. 1128 67

We studied polyamine (PA) biosynthesis, oxidation and conjugation in asynchronously dividing cells of tobacco BY-2 cell suspension culture (Nicotiana tabacum L.) during 7-day growth cycle. We analyzed the levels of free and conjugated PAs and the activities of biosynthetic and catabolic enzymes during the subculture interval. The contents of free spermidine and spermine started to increase after the inoculation into the fresh medium, positively correlated with the mitotic activity of BY-2 cells and reached their maxima at the beginning of exponential phase on day 3. On the contrary, the endogenous level of free Put showed a transient decline in the lag-phase, and then increased till the end of exponential phase (day 5). The time-course of the content of PCA-soluble conjugates showed a trend similar to that of the free PAs. The inoculation of BY-2 cells into the fresh medium resulted in a sharp increase in the activities of ornithine decarboxylase (ODC, EC 4.1.1.17) and S-adenosylmethionine decarboxylase (SAMDC; EC 4.1.1.50). Arginine decarboxylase (ADC; EC 4.1.1.19) activity remained low during the whole subculture interval. The rise of diamine oxidase (DAO; EC 1.4.3.6) in the first day after subculture coincided with the decrease in free Put level. De novo synthesis of PAs in BY-2 cells after inoculation into the fresh medium and the participation of both PA conjugation with hydroxycinnamic acids and Put oxidative degradation in maintaining of free PA levels during the growth cycle are discussed.
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PMID:Polyamine metabolism during the growth cycle of tobacco BY-2 cells. 1590 89

Effects of salt stress on polyamine metabolism and ethylene production were examined in two rice (Oryza sativa L.) cultivars [I Kong Pao (IKP), salt sensitive; and Pokkali, salt resistant] grown for 5 d and 12 d in nutrient solution in the presence or absence of putrescine (1 mM) and 0, 50, and 100 mM NaCl. The salt-sensitive (IKP) and salt-resistant (Pokkali) cultivars differ not only in their mean levels of putrescine, but also in the physiological functions assumed by this molecule in stressed tissues. Salt stress increased the proportion of conjugated putrescine in salt-resistant Pokkali and decreased it in the salt-sensitive IKP, suggesting a possible protective function in response to NaCl. Activities of the enzymes ornithine decarboxylase (ODC; EC 4.1.1.17) and arginine decarboxylase (ADC; EC 4.1.1.19) involved in putrescine synthesis were higher in salt-resistant Pokkali than in salt-sensitive IKP. Both enzymes were involved in the response to salt stress. Salt stress also increased diamine oxidase (DAO; 1.4.3.6) and polyamine oxidase (PAO EC 1.5.3.11) activities in the roots of salt-resistant Pokkali and in the shoots of salt-sensitive IKP. Gene expression followed by reverse transcription-PCR suggested that putrescine could have a post-translational impact on genes coding for ADC (ADCa) and ODC (ODCa and ODCb) but could induce a transcriptional activation of genes coding for PAO (PAOb) mainly in the shoot of salt-stressed plants. The salt-resistant cultivar Pokkali produced higher amounts of ethylene than the salt-sensitive cultivar IKP, and exogenous putrescine increased ethylene synthesis in both cultivars, suggesting no direct antagonism between polyamine and ethylene pathways in rice.
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PMID:Putrescine differently influences the effect of salt stress on polyamine metabolism and ethylene synthesis in rice cultivars differing in salt resistance. 2047 77

Unlike in flowering plants, the detailed roles of the enzymes in the polyamine (PA) pathway in conifers are poorly known. We explored the sequence conservation of the PA biosynthetic genes and diamine oxidase (DAO) in conifers and flowering plants to reveal the potential functional diversification of the enzymes between the plant lineages. The expression of the genes showing different selective constraints was studied in Scots pine zygotic embryogenesis and early seedling development. We found that the arginine decarboxylase pathway is strongly preferred in putrescine production in the Scots pine as well as generally in conifers and that the reduced use of ornithine decarboxylase (ODC) has led to relaxed purifying selection in ODC genes. Thermospermine synthase (ACL5) genes evolve under strong purifying selection in conifers and the DAO gene is also highly conserved in pines. In developing Scots pine seeds, the expression of both ACL5 and DAO increased as embryogenesis proceeded. Strong ACL5 expression was present in the procambial cells of the embryo and in the megagametophyte cells destined to die via morphologically necrotic cell death. Thus, the high sequence conservation of ACL5 genes in conifers may indicate the necessity of ACL5 for both embryogenesis and vascular development. Moreover, the result suggests the involvement of ACL5 in morphologically necrotic cell death and supports the view of the genetic regulation of necrosis in Scots pine embryogenesis and in plant development. DAO transcripts were located close to the cell walls and between the walls of adjacent cells in Scots pine zygotic embryos and in the roots of young seedlings. We propose that DAO, in addition to the role in Put oxidation for providing H2O2 during the cell-wall structural processes, may also participate in cell-to-cell communication at the mRNA level. To conclude, our findings indicate that the PA pathway of Scots pines possesses several special functional characteristics which differ from those of flowering plants.
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PMID:Thermospermine Synthase (ACL5) and Diamine Oxidase (DAO) Expression Is Needed for Zygotic Embryogenesis and Vascular Development in Scots Pine. 3192 Dec 49