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排序方式: 共有71条查询结果,搜索用时 15 毫秒
1.
Purpose: Environmental changes generate free radicals and reactive oxygen species (ROS) resulting in abiotic stress in plants. This causes alterations in germination, morphology, growth and development ultimately leading to yield loss. Gamma irradiation was used to experimentally induce oxidative damage in an important pulse crop Vigna radiata (L.) Wilczek or mung bean. Our research was aimed towards augmentation of oxidative stress tolerance through treatment with a group of aliphatic amines known as polyamines.

Materials and methods: We used sub-lethal doses of gamma irradiation to generate oxidative damage which was evaluated using Nitro blue tetrazolium (NBT) staining, total antioxidant activity, 1, 1-Diphenyl-2-picryl hydrazyl (DPPH) radical scavenging assay, proline content and lipid peroxidation. Changes in internal free polyamines and messenger ribonucleic acid (mRNA) expression of key rate-limiting S-adenosylmethionine decarboxylase (SAMDC) enzyme in polyamine biosynthetic pathway was studied using real-time polymerase chain reaction (PCR).

Results: We observed increased oxidative damage with higher irradiation dose which was partially alleviated by putrescine treatment. Internal levels of putrescine and spermidine increased with 1?mM (50 and 100?Gy) and 2?mM putrescine treatment. Expression of SAMDC also increased with putrescine treatment.

Conclusion: This study shows that treatment with putrescine can partially alleviate oxidative damage caused by gamma rays.  相似文献   

2.
Polyamines are cationic amines essential for cellular proliferation. Recently, their role in hair follicle (HF) growth has started to be explored, but their exact function is still obscure. In the October issue of Experimental Dermatology, Luke et al. follow the observation that putrescine overproducing mice and hairless (HR) mutant mice show a similar clinical phenotype of hair loss and dermal cyst formation. They show that HR and putrescine form a negative regulatory feedback mechanism, which might regulate hair cycling and therefore control hair growth. This study clearly demonstrates that a strong connection exists between HR and polyamines although there are probably additional molecular pathways involved in the polyamine regulation of hair growth which remain to be discovered.  相似文献   
3.
Putrescine metabolism in human brain tumors   总被引:4,自引:0,他引:4  
Summary The metabolism of the polyamines, putrescine, spermidine and spermine, was studied in human brain and brain tumors. Samples of brain and tumors were incubated with3H-putrescine and the amounts of labeled polyamines were measured. The amount of putrescine conversion was found to be greater in tumors that in normal brain samples. Furthermore, the metabolism of putrescine in brain tumors was related to tumor type and appeared to correlate with the degree of malignancy. The significance of these findings with regard to positron emission tomographic scanning and therapy of patients with malignant gliomas is discussed.  相似文献   
4.
A sensitive and reproducible method for quantitation of polyamines in erythrocytes by high-performance liquid chromatography (HPLC) is described. Spermidine and spermine are first converted to fluorescent dansyl derivatives and are then separated in less than 15 minutes on a C18 reverse-phase cartridge using methanol in water mobile phase. Sensitivity of the method is 20 pmol with recoveries that average 96% and 95% for spermidine and spermine, respectively. Precision study revealed an average mean coefficient of variation of 5.42 ± 2.95 (mean ± S.D.) from four levels of the polyamines (8.2 to 354.9 nmol/g hemoglobin [Hgb]). The normal ranges for 30 apparently healthy men and women, aged 20–60 years, were 2.9–33.7 nmol/g Hgb (± 2 S.D. from mean) for spermidine and 0-20.9 nmol/g Hgb for spermine. The quantity of putrescine was negligible. Feasibility of this method was evaluated in serial specimens from an advanced-stage patient with prostate cancer who was receiving multiple-modality therapy. Results revealed that this HPLC method can be used in quantifying circulating polyamines in clinical specimens.  相似文献   
5.
抗咯萘啶的伯氏疟原虫感染红细胞多胺量的测定   总被引:1,自引:0,他引:1       下载免费PDF全文
目的:了解疟原虫的多胺代谢与咯萘啶(PND)抗药性的关系。方法:感染伯氏疟原虫ANKA株(PS)和由该株培育的中抗PND品系(PRA)及高抗PND品系(PRB)的昆明株小鼠于腹腔接种(ip)后d7取血,经薄层层析后用荧光分光光度法测定正常RBC、PS、PRA和PRB感染RBC的丁二胺(PTC)、精脒(SPD)和精胺(SPM)量。另有感染PS和PRB的小鼠于ip后d6分别1次灌胃(ig)PND5mg/kg和10mg/kg,d7取血,按上述方法测定给药后感染RBC的多胺量,并与不给药组比较。结果:PS感染RBC的多胺量均明显高于未感染疟原虫的正常RBC,而感染PRA和PRB的RBC多胺量又显著高于PS感染RBC,且多胺量的增高与抗性程度有关。经PND治疗后PS感染RBC的SPD和SPM较未治疗组显著下降,而PRB感染RBC则未见明显变化。结论:伯氏疟原虫对PND的抗药性与其多胺代谢有关。  相似文献   
6.
The effect of difluoromethylornithine (DFMO), a specific inhibitor of ornithine decarboxylase activity, was evaluatedin vivo andin vitro on the growth of a gastrin-sensitive human colon carcinoma (WiDr).In vivo, mice bearing the tumor treated with pentagastrin had larger tumors with higher ornithine decarboxylase activity and polyamine content (P<0.05) than mice not treated with pentagastrin. Difluoromethylornithine treatment significantly decreased ornithine decarboxylase in both the pentagastrin-treated and the untreated animals; however, DFMO had no effect on tumor volume, weight, protein, or DNA content. In cell culture, gastrin treatment increased WiDr cell number and [3H]thymidine incorporation in the presence or absence of serum. In serum-free conditions, however, gastrin stimulated cell growth without concomitantly increasing ODC activity. DFMO, on the other hand, decreased both ODC activity and growth. These studies suggest that the trophic effect of gastrin on WiDr human colon cancer is independent of ODC activity. Since gastrin treatment increased ODC activityin vivo, gastrin may interactin vitro with other factors present in serum that can alter ODC activity.Supported by NIH First CA50303 and American College of Physicians Research and Teaching Award to Dr. Smith.  相似文献   
7.
8.
Quinolone antibiotics inhibit eukaryotic as well as prokaryotic cell growth and protein synthesis. To determine whether these properties adversely affect hepatic growth and recovery following surgical resection, five groups of healthy, adult male rats (n = 7–8/group) were treated for 10 days with equal volumes of either ofloxacin (50 mg/kg), fleroxacin (25mg/kg), ciprofloxacin (25 mg/kg), norfloxacin (15mg/kg) or sterile saline (controls) prior to 70% partial hepatectomy (PH) and daily thereafter until death. Restituted liver mass, DNA and protein synthesis rates were determined at 24, 48 and 72 h PH. The results of the study revealed that all parameters of hepatic regeneration were similar in the five study groups at each time interval. To ensure that an effect on hepatic regeneration was not dose-dependent, additional experiments were performed where 1, 10 and 100 mg/kg ciprofloxacin was administered and DNA synthesis was measured 24 h post-PH. Once again, the results were similar to sterile saline-treated controls. These findings suggest that the quinolone antibiotics are unlikely to have an adverse effect on hepatic recovery following surgical resection of the liver and are safe to use in that setting.  相似文献   
9.
Administration of allylglycine to mice (.8 nmole/kg, 1. p.) results in a depletion of GABA levels, and it is accompanied by a decrease in SAM-DC activity and spermidine and spermine levels (Pajunen et al., 1979). Here we describe a biphasic effect on the acetylation of putrescine and spermidine in mouse brain homogenate. There appears to be an inverse correlation between the initial decrease in spermidine levels at 2 hours and the increase in the acetylation of spermidine. This is suggestive of a conversion of spermidine, probably through N -acetylspermidine to putrescine. The peak of putrescine acetylation observed by us at 4 hours may also reflect a conversion of putrescine, via acetylputrescine to GABA. The inter conversion hypothesis is supported by the fact that putrescine levels remain essentially stable in spite of a significant depletion of spermidine and spermine. In addition, there is a decrease in putrescine and spermidine acetylation at 8 hours, which coincides with the increase in ODC activity and the increase towards control levels of GAD activity (Pajunen et al., 1979). Such inverse correlations suggest a mechanism for replenishment of polyamines once GAD activity returns to control levels.  相似文献   
10.
Abstract. Putrescine transport was investigated in isolated brush border and basolateral membrane vesicles prepared from the rabbit enterocyte. Brush border vesicles were oriented right-side-out and basolateral vesicles inside-out, forming a model representing uptake and extrusion across the intestinal epithelium. Putrescine transport across both membranes was initially rapid, and 66% of the equilibrium uptake was achieved within the first minute. According to osmo-plots and measurements at 4C, 20% of total incorporation presented binding to the membrane. In order to estimate actual uptake into the vesicles, Km was calculated from the differences in putrescine incorporation at 37C and 4C, and was 12.7 μmol L-1 for brush border uptake and 38.2 μmol L-1 for basolateral extrusion. Putrescine uptake into brush border and basolateral membrane vesicles was not enhanced in the presence of an Na+ gradient. When Na+ was substituted with an uncharged solute, mannitol, putrescine incorporation was increased, indicating that putrescine uptake is not Na+-dependent and that cations might interfere with the carrier. Paraquat and methylglyoxal-bis(guanylhydrazone), known to share the polyamine transport system, inhibited putrescine incorporation in both membrane vesicle preparations. Basolateral carrier showed significantly higher sensitivity to cations. We conclude that putrescine uptake across the apical membrane and extrusion across the basolateral membrane of the enterocyte are mediated by two different and independent carriers which differ in their electrical properties.  相似文献   
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