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1.
Polyamine biosynthesis in trichomonads   总被引:1,自引:0,他引:1  
Trichomonas vaginalis, Tritrichomonas foetus and Trichomitus batrachorum grown in modified Diamond's medium all had high concentrations of putrescine and lower concentrations of spermidine and spermine. Ornithine decarboxylase (ODC; EC 4.1.1.17) was detectable in all three species although at significantly different levels. Trichomonas vaginalis had the highest activity (typically around 1.85 nmol min-1 (mg protein)-1), Trichomitus batrachorum the lowest (0.11 nmol min-1 (mg protein)-1). The Trichomonas vaginalis ODC had an apparent Mr of 230 000 and was severely inhibited by alpha-difluoromethylornithine (DFMO). S-Adenosyl-methionine decarboxylase (EC 4.1.1.50) could not be detected in T. batrachorum but was present in the other two species. Arginine decarboxylase was apparently absent from all three. All three trichomonad species were able to accumulate spermidine and putrescine from the medium. When T. vaginalis was grown in the presence of DFMO (4 mM), which had little effect on parasite growth, ODC activity was reduced by over 99% and the polyamine content was altered; putrescine concentrations were decreased, those of spermidine and spermine remained the same or were raised. DFMO-treated cells accumulated more exogenous putrescine than untreated control cells. The results suggest that the lack of effect of DFMO on T. vaginalis in culture was due to the parasite being able to accumulate polyamines from the growth medium. It appears, therefore, that testing DFMO and similar compounds in axenic trichomonad cultures may well not give a true indication of their effectiveness in vivo where sources of exogenous polyamines may not be available.  相似文献   

2.
It has been long known that the physiological concentrations of polyamines putrescine, spermidine and spermine are essential for cell growth. However, the role of endogenous polyamines in behavior function is poorly understood at present. This study investigated animals' behavioral performance and neurochemical changes in the hippocampus and prefrontal cortex following i.c.v. microinfusion of difluoromethylornithine (DFMO), a potent inhibitor of putrescine synthesis. Rats with low (25 μg) and high (50 μg) doses of DFMO spent significantly less time on the open arms and more time on the enclosed arms in the elevated plus maze relative to the saline controls, with no performance changes in the open field. The two DFMO groups were not impaired in the place and cued navigation, reversal training and probe tests in the water maze task. In the object recognition memory task, all three groups could detect the novel object, but rats in the high dose DFMO group spent significantly less time exploring displaced objects relative to the controls. DFMO treatment at both doses resulted in an 80%–90% reduction of putrescine level in the CA1, CA2/3 and dentate gyrus (DG) sub-regions of the hippocampus and the prefrontal cortex with minimal effects on the spermidine and spermine levels. Decreased spermidine/spermine molar ratio was found in DG and there were increased glutamate and GABA levels and their molar ratios in a region-specific manner in the DFMO groups. These results demonstrate that acute depletion of putrescine by DFMO produces anxiety-like behavior and impairs memory for the object displacement without affecting animals' locomotor and exploratory activity and spatial learning and memory. Multiple regression analysis data suggest the different roles of endogenous putrescine, spermidine and spermine on behavior function. The spermidine/spermine and glutamate/GABA ratios in hippocampal DG are strongly associated with anxiety-like behavior in the DFMO rats.  相似文献   

3.
外源多胺对大鼠早期再生肝鸟氨酸脱羧酶蛋白水平的调节   总被引:1,自引:0,他引:1  
目的 研究多胺(腐胺、精脒和精胺)对大鼠再生肝鸟氨酸脱羧酶(ODC)蛋白水平的调节,分析多胺在肝再生中的作用.方法 外源多胺(溶于0.9%NaCl)皮下注射雄性SD大鼠(180~220 g),部分肝切除(PH)诱导的大鼠再生肝中ODC蛋白水平的分析采用免疫印迹(Western blotting)方法.结果 高剂量的腐胺(20 ms/kg体重)、精脒(0.15 mg/kg体重)和精胺(6 mg/kg体重)处理后,ODC蛋白水平在PH后12 h内均低于对照组,且各组间变化趋势相近;而低剂量腐胺(0.02 mg/kg体重)、精脒(0.03 mg/kg体重)及精胺(0.06 ms/kg体重)处理组在PH后4h ODC水平迅速升高,分别比对照组高15.1%、29.5%和30.3%.结论 一定剂量的多胺对大鼠早期再生肝ODC蛋白水平有反馈调节作用,其中精脒、精胺的作用较强,腐胺较弱.  相似文献   

4.
目的: 研究多胺、鸟氨酸脱羧酶(ODC)及精脒/精胺乙酰基转移酶(SSAT)在异丙肾上腺素所致大鼠心肌肥厚中的作用及机制。方法: 异丙肾上腺素(ISO)皮下注射复制大鼠心肌肥厚模型,应用反向高效液相色谱(RP-HPLC)、RT-PCR和Western blotting结合图像分析系统,分别检测ISO作用不同时点大鼠心肌组织多胺含量、ODC和SSAT mRNA和蛋白的表达。结果: 与对照组比较,心脏重量参数在ISO注射后7 d时显著增加,ISO注射后1 d时腐胺含量增加(P<0.05),5 d、7 d时显著增加(P<0.01);精脒含量在ISO注射后3 d时开始增加,ISO注射后7 d时增加显著(P<0.01),精胺含量略有增多(P<0.05),总多胺池显著增加。心肌组织ODC和SSAT的 mRNA表达在ISO注射后1 d时升高(P<0.05或P<0.01),并持续在较高水平。心肌组织ODC和SSAT的蛋白表达分别在ISO注射后1 d和ISO注射后5 d时升高,ISO注射后7 d时显著升高(P<0.01)。结论: 大鼠心肌组织多胺含量增加和ODC、SSAT的表达增强可能参与ISO所致心肌肥厚的病理过程。  相似文献   

5.
In AKR/J mice inoculated intraperitoneally with protoscoleces ofEchinococcus multilocularis, the oral administration of alpha-difluoromethylornithine (DFMO) in drinking water had no obvious effect on the development of hydatid cysts. The DFMO treatment also caused no apparent depletion of three major polyamines (putrescine, spermidine, and spermine) in the cysts, although a slight reduction in the putrescine level was detected. The failure of DFMO treatment to reduce the growth of cysts in mice may result from the absence of ornithine decarboxylase in the parasite.  相似文献   

6.
目的:探讨鸟氨酸脱羧酶(ODC)/多胺系统在缺血预适应(IPC)心肌保护中的作用。方法:应用离体灌流大鼠心脏复制模拟心肌缺血/再灌注模型。心脏随机分为6组:对照组 (control)、缺血/再灌注组 (IR)、弱缺血预适应组 (IPCw)、强缺血预适应组 (IPCs)、IPCw+多胺抑制剂组 (DF-EG-IPCw)和IPCs+多胺抑制剂组(DF-EG-IPCs)。免疫印迹法定量分析多胺合成限速酶鸟氨酸脱羧酶 (ODC)的表达;高效液相色谱测定心肌组织中的多胺(腐胺、精脒、精胺)含量;Powerlab多导生理记录系统记录心脏功能;氯化三苯基四氮唑 (TTC) 染色检测心肌梗死面积;TUNEL方法检测细胞凋亡率,比较其中的差异性。结果:(1)与对照组比,IR组ODC表达下调,腐胺含量增加,精胺含量减少,总多胺池减少(P<0.05),此时心功能下降(LVDP、HR、CF均低于对照组,P<0.05),心肌梗死面积及心肌细胞凋亡率增加(P<0.05);(2)与IR组比,弱及强缺血预处理组(IPCw、IPCs)心肌ODC表达上调,腐胺含量减少,精胺含量增加,总多胺池增加(P<0.05或P<0.01),此时大鼠心功能有明显改善(LVDP、HR、CF与IR组比,P<0.05),心肌梗死面积及心肌细胞凋亡率均明显降低(P<0.01);(3)给予多胺抑制剂后,心肌ODC表达,腐胺、精脒、精胺及总多胺池含量均明显降低(DF-EG-IPCw组 vs IPCw组;DF-EG-IPCs组vs IPCs组,P<0.05或P<0.01),心功能明显下降(P<0.05),心肌梗死面积及细胞凋亡率均明显增加(P<0.05)。结论:缺血预适应能明显上调大鼠心肌ODC/多胺系统,减轻缺血/再灌注心肌损伤;多胺合成代谢抑制剂取消了预适应介导的心功能改善、缩小心肌梗死面积及减少心肌细胞凋亡的作用,提示ODC/多胺系统可能参与了缺血预适应介导的心肌保护作用。  相似文献   

7.
In order to elucidate the possible role of polyamines in the mobilization of mineral from long-term bone cultures stimulated with parathyroid hormone we have measured the activity of ornithine decarboxylase in osteoblasts, the levels of polyamines in calvarial bone and determined the effect of added polyamines and inhibitors of polyamine biosynthesis on calcium mobilization. Parathyroid hormone (10 nmol l-1) stimulated omithine decarboxylase activity by approximately 50% in both cultured bone cells of osteoblastic phenotype, UMR 106 and in mouse calvarial osteoblast-like cells. In mouse calvaria the levels of putrescine and spermidine were increased by parathyroid hormone after 24 hours. The levels of spermine were very low and were unchanged by parathyroid hormone. The two polyamine synthesis inhibitors alpha-difluoromethylornithine (DFMO; 2 mmol l-1) and methylglyoxal-bis-guanylhydrazone (MGBG; 50 mu mol l-1) did not significantly affect the mobilization of 45Ca from parathyroid hormone-stimulated bones. All three polyamines, putrescine, spermidine and spermine, inhibited the mobilization of 45Ca induced by parathyroid hormone in a dose-dependent manner. The inhibition induced by putrescine was reversible. In summary, we have shown that parathyroid hormone increases the accumulation of polyamines in bone, but the effect is small. Furthermore, inhibition of polyamine biosynthesis does not reduce parathyroid hormone-induced mineral mobilization and the addition of polyamines leads to a reduced rather than a stimulated mineral mobilization. Thus, polyamines do not seem to be critically involved in the changes in bone resorption induced by parathyroid hormone.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

8.
外源多胺对大鼠再生肝细胞鸟氨酸脱羧酶基因转录的调节   总被引:4,自引:3,他引:1  
目的 研究天然多胺(腐胺、精脒和精胺)对大鼠再生肝细胞鸟氨酸脱羧酶(ODC)基因转录的调节,探讨多胺在肝再生中的作用.方法 大鼠部分肝切除术诱导再生肝,采用原位杂交技术分析ODC mRNA的表达量,外源多胺(溶于0.9%NaCl)的处理用皮下注射法.结果 外源多胺处理后,再生肝ODC mRNA水平的变化趋势与对照组相似,但不同种类、剂量的多胺,结果差异明显.在所观察到的整个肝再生期间,高剂量腐胺(20 mg/kg体重)处理组mRNA水平始终低于对照组,特别在部分肝切除后2、4和10 h与对照组相比具有显著性差异(P<0.05);低剂量(0.02 mg/kg体重)的腐胺处理组,只在4 h和12 h显著高于对照组.高剂量精脒(0.15 mg/kg体重)处理组的ODC mRNA水平始终低于对照组(在10 h例外);而低剂量(0.03 mg/kg体重)处理组则不同,ODC mRNA水平表现出先抑制(在2 h)后促进(在4 h和6 h)的特点.精胺的作用与精脒相似.结论 不同浓度的多胺(主要是精脒和精胺)对大鼠再生肝细胞ODC基因转录存在着反馈调节作用.  相似文献   

9.
In macrophages, basal polyamine (putrescine, spermidine, and spermine) levels are relatively low but are increased upon IL-4 stimulation. This Th2 cytokine induces Arg1 activity, which converts arginine into ornithine, and ornithine can be decarboxylated by ODC to produce putrescine, which is further converted into spermidine and spermine. Recently, we proposed polyamines as novel agents in IL-4-dependent E-cadherin regulation in AAMs. Here, we demonstrate for the first time that several, but not all, AAM markers depend on polyamines for their IL-4-induced gene and protein expression and that polyamine dependency of genes relies on the macrophage type. Remarkably, Arg1-deficient macrophages display rather enhanced IL-4-induced polyamine production, suggesting that an Arg1-independent polyamine synthesis pathway may operate in macrophages. On the other side of the macrophage activation spectrum, LPS-induced expression of several proinflammatory genes was increased significantly in polyamine-depleted CAMs. Overall, we propose Arg1 independently produced polyamines as novel regulators of the inflammatory status of the macrophage. Indeed, whereas polyamines are needed for IL-4-induced expression of several AAM mediators, they inhibit the LPS-mediated expression of proinflammatory genes in CAMs.  相似文献   

10.
The promastigote form of Leishmania donovani is sensitive to growth inhibition by DL-alpha-difluoromethylornithine (DFMO), an inhibitor of ornithine decarboxylase (ODC), the first enzyme of the polyamine biosynthetic pathway, with an EC50 value of approximately 30 microM. Exposure of a wild type (DI700) cell population to gradually increasing concentrations of DFMO resulted in the selection of a strain of Leishmania, DFMO-10, which was capable of proliferating in 10 mM DFMO. DFMO-10 cells possessed an EC50 value for DFMO greater than 4 mM, and were cross-resistant to alpha-methylornithine, alpha-monofluoromethyl-3,4-dehydroornithine methyl ester, and delta-methyl-acetylenic putrescine, three other inhibitors of ODC activity. DI700 and DFMO-10 cells accumulated and/or transported [3H]DFMO and a spectrum of basic, neutral, and acidic amino acids at comparative rates. However, the DFMO-resistant Leishmania, if suspended in culture medium in the absence of DFMO for several days, expressed up to 15-fold greater levels of ODC activity than did wild-type cells. The overexpressed ODC in mutant cells appeared kinetically normal, since the ODC activities from DI700 and DFMO-10 cells possessed similar apparent Km values for ornithine and were equally sensitive to inactivation by DFMO. Incubation of extracts of DFMO-10 cells, but not of wild-type parental cells, with [3H]DFMO for 1 h resulted in the labeling of a polypeptide, presumably ODC, which migrated with a molecular weight of 76,000 +/- 4000 on SDS-gel electrophoretograms. As a consequence of the elevated ODC activities, the levels of putrescine in mutant cells released from DFMO exposure were also elevated by about 15-fold over those of wild-type cells, although spermidine levels in DI700 and DFMO-10 cells were similar. In the absence of prolonged selective pressure, the resistance to DFMO, the ODC activity, and the putrescine levels of DFMO-10 cells all returned to those of wild type cells, indicating that the mutant phenotype of DFMO-selected L. donovani was unstable.  相似文献   

11.
The effects of Prostaglandin (PG) E2 treatment of human T lymphocytes on polyamine metabolism were investigated. PGE2 is known to inhibit lymphocyte proliferation, while polyamines play an important role in several biochemical processes leading to increased cell growth. Preincubation of T lymphocytes with PGE2 (10-6 M) for 10 min. was able to increase ornithine decarboxylase (ODC) activity and putrescine as well as spermine levels, while spermidine concentration was drastically reduced. After 30 and 60 min of treatment, a decrease in ODC activity and putrescine concentration was observed. On the contrary, the initial inhibition of sperrnine-NI-acetyl-transferase (SAT) activity was followed by a progressive increase of this catabolic enzyme. These changes were related to modifications of cAMP concentrations. Our data may help clarify the mechanisms underlying the biphasic effect of PGE2, which ultimately leads to inibition of cell proliferation.  相似文献   

12.
Polyamines have been previously implicated in the mediation of blood-brain barrier breakdown induced by cryogenic injury (H Koenig, AD Goldstone, CY Lu, Biochem Biophys Res Commun 116:1039, 1983). We studied acute (less than 5 minute) changes in capillary ultrastructure, microvascular permeability, and the levels of polyamines and their rate regulating synthetic enzyme ornithine decarboxylase (ODC) in rat cerebral cortex after focal cold injury. Microvascular permeability was measured by relative transport of intravenously administered fluorescein. Capillary ultrastructure was studied by quantitative stereology and morphometry after intravenous administration of horseradish peroxidase. Focal cold injury induced a 2.5-, 3.8-, 1.7-, and 1.4-fold increase in the levels of ODC, putrescine, spermidine and spermine, and a 46-fold increase in fluorescein uptake in perilesional cortex. Few capillaries in control cortex contained endocytic pits or horseradish peroxidase-positive vesicles, whereas most capillaries near lesions showed these structures. Cryoinjury induced a 5-fold increase in the relative volume of microvilli and horseradish peroxidase vesicles, a 2.3-fold increase in area of luminal endocytic pits, and a 6.3-fold increase in area of abluminal exocytic pits. The ODC inhibitor alpha-difluoromethylornithine blocked the cryoinjury-induced changes in ODC, polyamines, fluorescein uptake, and capillary ultrastructure. Putrescine negated the effect of alpha-difluoromethylornithine or capillary ultrastructure, and was previously shown to nullify the alpha-difluoromethylornithine effects on polyamines and fluorescein permeability (cited above). These data link rapid changes in ODC and polyamines to blood-brain barrier breakdown, and suggest that the abnormal permeability is associated with an acute, polyamine-mediated stimulation of microvillus formation, endocytosis, and vesicular transport in capillary endothelium.  相似文献   

13.
The aim of this study was to investigate to what extent polyamine metabolism in the small intestine of the rat is controlled by the enteric nervous system. Polyamine metabolism was followed by measuring the activity of ornithine decarboxylase (ODC) and in some instances also the content of polyamines (putrescine, spermidine and spermine). ODC activity in the intestine was increased when intraluminal pressure was increased and 3 h after placing cholera toxin in the intestinal lumen. Cholera toxin also increased the tissue putrescine content. Atropine or hexamethonium given i.v. did not influence the evoked changes of ODC activity. The pressure induced changes were not decreased by placing lidocaine on the serosal surface. On the other hand, the ODC activity of control segments were decreased by hexamethonium or atropine. The presence of glucose in the intestinal perfusate did not augment tissue ODC activity, neither did the heat stable enterotoxin from Escherichia coli (STa). It is concluded that the effect on polyamine metabolism evoked by luminal pressure or cholera toxin seems not to be mediated via nerves, while nerves seem to influence ODC activity during control conditions. The experiments with enterotoxins suggest that cAMP is the intracellular second messenger controlling intestinal ODC activity.  相似文献   

14.
目的:通过观察运动训练对老龄大鼠心肌多胺代谢、心肌抗炎及抗氧化能力的影响,探讨多胺代谢在运动训练延缓心肌衰老中的作用。方法:实验分为3组:老年运动组(Old+Ex),18月龄Wistar大鼠梯度跑台运动6周;老年组(Old),与Old+Ex组月龄相同的Wistar大鼠;青年组(Young),3月龄Wistar大鼠。高效液相色谱测定心肌组织中多胺(腐胺、精脒和精胺)含量;[14C]标记液闪计数方法测定心肌组织中多胺合成限速酶鸟氨酸脱羧酶(ODC)与多胺分解限速酶精脒/精胺乙酰转移酶(SSAT)活性;比色法检测心肌组织中超氧化物歧化酶(SOD)活性和丙二醛(MDA)含量;酶联免疫吸附(ELISA)法检测心肌组织中肿瘤坏死因子α(TNF-α)和白细胞介素1β(IL-1β)含量;超声心动图记录大鼠心脏功能;透射电镜观察心肌组织超微结构变化。结果:与Young组比,Old组大鼠心肌组织中ODC活性下降, SSAT活性升高, 精脒、精胺及总多胺池水平显著降低;心肌SOD活性下降,MDA、TNF-α和IL-1β水平升高(P<0.05);超声心动图显示,Old组大鼠左心室收缩末期直径(LVESD)与舒张末期直径(LVEDD)均明显增大,左心室射血分数(LVEF)与缩短分数(LVFS)降低(与Young组比,P<0.01)。Old+Ex组大鼠心肌组织中ODC活性增加,SSAT活性下降,精脒及总多胺池水平明显增加;心肌SOD活性升高,MDA、TNF-α和IL-1β水平均显著降低(与Old组比,P<0.05);左室功能有明显改善。超微结构观察可见Old组心肌肌丝排列不整齐,可见大量脂褐素颗粒沉积,线粒体基质疏松;Old+Ex组心肌肌节结构清晰,线粒体基质致密,嵴排列整齐。结论:运动训练通过上调多胺合成代谢、抑制其分解代谢对抗衰老引起的心肌多胺水平降低;运动训练可提高老龄心肌抗炎、抗氧化能力。维持老龄心肌多胺池在适当水平可能是运动延缓心肌衰老的部分机制之一。  相似文献   

15.
A standardized stenosis was induced by applying a silver clip around the left renal artery in male rats. This resulted in arterial hypertension within 10 days (as determined by increase in heart weight). Ornithine decarboxylase (ODC) activity was determined in the right (untouched) kidney, the left kidney, and the adrenal glands 1 day, 10 days, and 3 months after the operation. There was no difference in ODC activity in the right kidney of the operated animals when compared with matched controls. In the left kidney (with artery stenosis), ODC activity decreased to 40% after 1 day. A partial recovery was seen after 10 days (ODC activity 70% of normal), and after 3 months ODC activity had normalized. Removal of the clip 1 day prior to killing induced in the 3-month group a more than two-fold increase in ODC activity in the previously clipped kidney; ODC activity in the contralateral kidney was not affected. Only minor changes in ODC activity occurred in the adrenal glands following the operation. Contents of putrescine and spermidine were increased in the left (stenotic) kidney, and after clip removal, also in the right (untouched) kidney. Our observations thus indicate that alterations in renal blood flow are rapidly followed by changes in ODC activity. Contents of putrescine, spermidine and spermine seemed to a great extent to be independent of the ODC activity.  相似文献   

16.
In order to develop an immunocytochemical method suitable for the study of the cellular localization and intracellular distribution of polyamines we have prepared and characterized antibodies to polyamines. Artificial immunogens were prepared by coupling putrescine, spermidine and spermine to a carrier protein. Immunogens containing bovine serum albumin as a carrier protein were used to immunize rabbits (polyclonal antibodies) and mice (for the production of Mabs). The specificity of the antibodies was tested in an ELISA system utilizing antigens synthesized from thyroglobulin and one of the polyamines. Polyclonal antibodies to putrescine, spermidine and spermine were obtained. However, these antibodies showed a variable degree of cross-reactivity to the polyamines not used for immunization. Two hybridoma cell lines were developed. The first, MPut88, selectively produces a Mab to putrescine, the second, MSpm/d88 produces a Mab which recognizes spermine and spermidine but does not react with putrescine.  相似文献   

17.
Polyamines are important for protein synthesis and tissue growth. In rat salivary glands, the activity of ornithine decarboxylase (ODC), the enzyme catalysing the formation of putrescine, and the content of putrescine, spermidine, spermine and N1-acetylspermidine were assayed after parasympathetic or sympathetic nerve stimulation in the presence of various autonomic receptor blockers. Increases in ODC activity occurred on activation of non-adrenergic and non-cholinergic receptors in response to parasympathetic nerve stimulation and on activation of alpha(alpha 1)- as well as of beta(beta 1)-adrenoceptors in response to sympathetic nerve stimulation. Moreover, in parotid glands, a beta(beta 1)-adrenoceptor-mediated inverse pathway for putrescine formation seemed to exist: from spermidine via N1-acetylspermidine.  相似文献   

18.
Effects of polyamines (0.05-1.2 mM) on the mechanical and electrical activities in the circular muscles of pre-(day 20 of pregnancy) and post-partum (10-15 h after delivery) rat myometria were studied. In the prepartum preparations, spermine and spermidine, added to the Mg-free Krebs solution, depressed contractions in a dose-dependent manner, whereas cadaverine and putrescine potentiated them. The latter agents depressed contractions when preparations were treated with indomethacin. Plateau potentials were spontaneously generated in the Mg-free solution in the prepartum circular muscle. The duration of the plateau became shorter, and spike potentials supermounted on the plateau potential were depressed when spermine or spermidine was applied. In the postpartum preparations, spike activity was depressed by spermine and spermidine. In both pre- and post-partum preparations, the membrane activity was little affected by cadaverine and putrescine. In view of the above findings, it was hypothesized that polyamines in general took the place of divalent cations in causing membrane stabilization. Cadaverine and putrescine probably caused a potentiation of contraction by stimulating the synthesis of endogenous prostaglandins.  相似文献   

19.

Background  

The antizyme family is a group of small proteins that play a role in cell growth and division by regulating the biosynthesis of polyamines (putrescine, spermidine, spermine). Antizymes regulate polyamine levels primarily through binding ornithine decarboxylase (ODC), an enzyme key to polyamine production, and targeting ODC for destruction by the 26S proteosome. Ornithine decarboxylase antizyme 3 (OAZ3) is a testis-specific antizyme paralog and the only antizyme expressed in the mid to late stages of spermatogenesis.  相似文献   

20.
Polyamine metabolism in filarial worms   总被引:1,自引:0,他引:1  
The human and animal filarial parasites Onchocerca volvulus, Dirofilaria immitis, Brugia patei and Litomosoides carinii contained low levels of putrescine but much higher levels of spermidine and spermine as estimated by ion-pair high pressure liquid chromatography; N-acetylated polyamines were present only in minute amounts. Enzyme activities of ornithine decarboxylase (EC 4.1.1.17) and arginine decarboxylase (EC 4.1.1.19), respectively, were not detectable. Experiments carried out with O. volvulus and D. immitis demonstrated the uptake and bioconversion of labeled polyamines. There is evidence for the existence of a complete reverse pathway generating putrescine from spermidine and spermine, respectively, in both worms. N-Acetylating enzyme activities were detected in 100,000 X g preparations of homogenates from D. immitis which were capable to acetylate putrescine, spermidine and spermine. Long term incubation of the worms in the presence of labeled polyamines resulted in the excretion of putrescine and N-acetylputrescine.  相似文献   

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