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1.
Previous reports have suggested that the ablation of the Period 2 gene (Per 2) leads to enhanced development of lymphoma and leukemia in mice. Employing immunoblot analyses, we have demonstrated that PER 2 is endogenously expressed in human breast epithelial cell lines but is not expressed or is expressed at significantly reduced level in human breast cancer cell lines. Expression of PER 2 in MCF-7 breast cancer cells significantly inhibited the growth of MCF-7 human breast cancer cells, and, when PER 2 was co-expressed with the Crytochrome 2 (Cry 2) gene, an even greater growth-inhibitory effect was observed. The inhibitory effect of PER 2 on breast cancer cells was also demonstrated by its suppression of the anchorage-independent growth of MCF-7 cells as evidenced by the reduced number and size of colonies. A corresponding blockade of MCF-7 cells in the G1 phase of the cell cycle was also observed in response to the expression of PER 2 alone or in combination with CRY 2. Expression of PER 2 also induced apoptosis of MCF-7 breast cancer cells as demonstrated by an increase in PARP [poly (ADP-ribose) polymerase] cleavage. Finally, our studies demonstrate that PER 2 expression in MCF-7 breast cancer cells is associated with a significant decrease in the expression of cyclin D1 and an up-regulation of p53 levels.  相似文献   

2.
Castor (Ricinus communis L.) stalks, which are a readily available by-product of this plant mainly cultivated for seed production, derived from experimental plantations grown in Northern Greece during the period April–October 1996 were assessed for their suitability as feed stocks for direct substitution of wood in particleboard. The average stalk yield of castor reached about 10 dry t/ha, which is higher than the average yield of forest in temperate zones. After harvesting, castor stalks were dried in a greenhouse to about 12% moisture content, and chipped by an automobile chipper and re-chipped in a hammermill. Castor particles and industrial wood particles mixed in various proportions were used as raw material for one-layer and for the middle layer of three-layer particleboards. A commercial E2 grade UF-resin was used as binder. Castor particles were characterized by a lower slenderness ratio and lower bulk density than industrial wood particles. The evaluation of the mechanical and hygroscopic properties of panels showed the following results: Partial substitution of wood by castor stalks resulted in the deterioration of all board properties. The presence of the unlignified pith and the configuration of castor particles seem to be responsible for the deleterious effect of castor stalks on board properties. However, comparing the properties of the boards produced in this study to relevant European and American Standards, it was found that, with the exception of screwholding strength for three-layer boards, the experimental one layer-, and three-layer boards containing up to 25% and 75% castor particles respectively meet or exceed the Standards requirements for interior boards.  相似文献   

3.
稻田15N标记尿素去向的研究   总被引:6,自引:1,他引:6  
 1987年在中国水稻研究所试验场应用15N示踪技术进行了多处理的田间微区试验。结果表明: 氮肥作基肥使用时,水稻对N素的吸收利用率差异不显著,而随着施用量的增加,在土壤中的N素残留率降低,而氮肥损失率显著提高;基肥配施PK肥对肥料N的去向无显著影响响,但配施适量稻草有助于提高水稻对肥料N的吸收量和土壤残留量,降低氮索损失;氮肥的使用期对肥料15N去向的影响十分显著,追肥的K素利用率比基肥高。稻田采用以水带氮施肥技术能明显地提高水稻的氮素吸收,增加土壤残留率和减少氮素损失,表明此技术是一项合理的稻田氮肥深施技术。  相似文献   

4.
BACKGROUND: Progressive cognitive decline is one of the hallmark symptoms of Alzheimer's disease (AD) which can be modeled by beta-amyloid injection into specific regions of brain. Since epigallocatechin-3-gallate (EGCG) is a potent antioxidant agent which its role against oxidative stress and inflammation has been shown in prior studies, we tried to determine whether EGCG administration protects against beta-amyloid-induced memory and coordination impairment in rats. METHODS: Animals (male Wistar rats) were divided into four groups: sham operated, EGCG-pretreated sham operated (sham+EGCG), untreated lesion (lesion), and EGCG-pretreated lesion (lesion+EGCG). Animals in lesion, lesion+EGCG, and sham+EGCG groups received sterile saline or saline plus EGCG (10 mg/kg) intraperitoneally one day pre-surgery and every other day for three weeks. The lesion was induced one day after EGCG pretreatment by injection of 4 microl of sterile saline or water containing 2 nmol/microl beta-amyloid (1-40) into the hippocampal fissure. For behavioral analysis, psychomotor coordination (PMC) index and spontaneous alternation behavior were assessed using Rota-rod Treadmill and Y-maze, respectively at the third week post-lesion. RESULTS: We found that beta-amyloid (1-40) injection into hippocampus can decrease these behavioral indexes in lesion group in comparison with sham group which is similar to behavioral changes in AD. On the other hand, pretreatment with EGCG can improve the PMC index and spatial Y-maze alternation in the lesion+EGCG group in comparison with lesion group. CONCLUSION: We concluded that EGCG can be effective in restoring beta-amyloid-induced behavioral derangements in rats regarding coordination and memory abilities.  相似文献   

5.
6.
The T36 strain of citrus tristeza virus (CTV) expressing green fluorescent protein gene (CTV-GFP) was used to detect replication of CTV in wild-type (WT) ‘Hamlin’ sweet orange plants and those transformed with the use of Agrobacterium tumefaciens strain harboring a binary vector with a coat protein gene from either T36 or T30 isolate of CTV. Soil-adapted WT and transgenic plants were challenged with CTV by grafting shoots from CTV-GFP infected plants. None of the transgenic plants appeared to be able to inhibit CTV replication as CTV-associated GFP fluorescence in all of them was detected by fluorescent microscopy. For the purpose of comparison of two different methods, CTV multiplication in transgenic plants was also examined by enzyme-linked immunosorbent assay (ELISA) assays. GFP-labeled CTV represents a useful tool for estimation of susceptibility of citrus cultivars or transgenic lines to CTV infection. This method using CTV-GFP is simpler, cheaper and less time-consuming than ELISA.  相似文献   

7.
Castor oil seeds were fermented under conditions commonly used in some local communities in Eastern Nigeria. Levels of selected biochemical constituents of fermented seeds were compared with those of unfermented seeds. The free amino acids — phenylalanine, tryptophan, tyrosine, serine, glutamic acid, cysteine, and gluamine — were detected by using thin-layer chromatography in the fermented sample extract, while none were detectable in the extract of unfermented seeds. Lipid analysis showed that the fermented seeds contained more unsaturated fatty acids than the unfermented seeds. Glutamine produced by the microorganisms responsible for fermentation is probably responsible for the characteristic flavor of foods seasoned with fermented castor oil seeds, known locally as ogiri.  相似文献   

8.
The difficulty in matching the herbage requirements of grazing dairy cows to herbage production, due mainly to the unpredictability of the latter., causes stocking rates to be too low for maximum per hectare production and, thus, cows to be underfed at certain times in the grazing season. Conserved forage may be used as a supplement for grazing dairy cows in order to reduce variation in forage intake by the cow, to allow pasture stocking rates to be increased and to increase the efficiency of land use. The effect of offering conserved forage with herbage on intakes and production is reviewed in comparison to both ad libitum and restricted herbage. Total nutrient intakes and milk fat + protein yields are reduced for cows offered herbage and supplementary forage compared with cows offered ad libitum herbage, but increased compared with cows offered a restricted herbage level. Increasing pasture stocking rates may allow increases in utilized metabolizable energy levels from grassland but further research is needed in this area. Both grass and maize silage supplements offer potential for increasing the efficiency of land use, but in the case of grass silage this is only achieved in the best management practices.  相似文献   

9.
Plant water use efficiency(WUE) is becoming a key issue in semiarid areas, where crop production relies on the use of large volumes of water. Improving WUE is necessary for securing environmental sustainability of food production in these areas. Given that climate change predictions include increases in temperature and drought in semiarid regions,improving crop WUE is mandatory for global food production. WUE is commonly measured at the leaf level, because portable equipment for measuring leaf gas exchange rates facilitates the simultaneous measurement of photosynthesis and transpiration. However,when those measurements are compared with daily integrals or whole-plant estimates of WUE, the two sometimes do not agree. Scaling up from single-leaf to whole-plant WUE was tested in grapevines in different experiments by comparison of daily integrals of instantaneous water use efficiency [ratio between CO2assimilation(AN) and transpiration(E); AN/E] with midday AN/E measurements, showing a low correlation, being worse with increasing water stress. We sought to evaluate the importance of spatial and temporal variation in carbon and water balances at the leaf and plant levels. The leaf position(governing average light interception) in the canopy showed a marked effect on instantaneous and daily integrals of leaf WUE. Night transpiration and respiration rates were also evaluated, as well as respiration contributions to total carbon balance. Two main components were identified as filling the gap between leaf and whole plant WUE: the large effect of leaf position on daily carbon gain and water loss and the large flux of carbon losses by dark respiration. These results show that WUE evaluation among genotypes or treatments needs to be revised.  相似文献   

10.
Summary All strains investigated of PVYc, PVYn and PVYo, even a strain of PVYo, which did not produce local lesions on ‘A6’, induced pin-point necrotic lesions on detached and non-detached leaflets of TE1 (Solanum chacoense) 3–4 days after inoculation. However, the local lesion production per cm2 on ‘A6’ leaflets was higher than that on leaflets of TE1 after inoculation with various dilutions of PVY. Moreover, the foliage production of TE1 was much lower than that of ‘A6’. Therefore TE1 is less suitable for routine detection of PVY than ‘A6’.  相似文献   

11.
Background: Molecular targeted therapy by different cell death inducers are recently considered in cancer therapy. The aim of this study was to compare the effect of cisplatin and inositol trisphosphate kinase inhibitor (caffeine) on human breast cancer cell line (MCF-7). The pattern of cell death in MCF-7 cells following the exposure to cisplatin and caffeine in individual and combination forms was characterized. Methods: MCF-7cells at late exponential phase were divided into two groups: control and experimental groups. Experimental group was exposed to cisplatin, caffeine and combination of them and control group was treated by vehicle. Forty-eight hours after incubation, floating and attached cells were collected separately. Flowcytometry analysis and electron microscopy were carried out on both attached and floating cells. Results: Two types of apoptotic and non-apoptotic cells were observed in the floating cells as well as in sub G1 cells of both experimental and control groups by electron microscopy. Both early and late stages of apoptosis were characterized and the attached cells remained unaffected. Conclusion: Although two different forms of cell death (apoptosis and non-apoptosis) were appeared in MCF-7 following exposure to cisplatin and caffeine, apoptosis was the major mechanism of cell death. The combination form of anti-cancer drugs with different mechanisms could decrease the dosage of employed anti-cancer drugs.Key Words: Cisplatin, Caffeine, Apoptosis  相似文献   

12.
The acid extract viscosities and β-glucan contents of ten two- and six-rowed barley cultivars grown at seven locations in three consecutive years in Spain were studied in the present work. The viscosities varied from 2·4 to 24·8 centistokes (cSt) and the mean value was 6·4 cSt. The average β-glucan content of barleys determined by HPLC was 3·5% with a range of 1·9–5·5%. Significant differences were found in both β-glucan content and acid extract viscosity between different cultivars, locations and years. The β-glucan contents and viscosities of winter cultivars were higher than those of spring. Cvs. Barbarrosa and Hatif de Grignon were the genotypes with the highest values for both parameters, while cv. Beka had the lowest viscosity and β-glucan content. Environmental factors influenced both parameters. The acid extract viscosities of barleys were correlated negatively with the amount of precipitation (r=−0·754;P<0·05). Barleys grown in wet and rainy areas (Girona and La Coruña) had lower viscosity values.  相似文献   

13.
Epoxidized polybutadiene (EPB) was prepared by polybutadiene (PB) withm-chloroperbenzoic acid (MCPBA) in homogeneous solution. EPB was blended with poly(3-hydroxybutyrate) (PHB) up to 30 wt% by solution-precipitation procedure. The thermal decomposition of PHB/EPB blends was studied by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and differential thermal analysis (DTA). The thermograms of PHB/EPB blends contained a two-step degradation process, while that of pure PHB sample exhibited only one-step degradation process. This degradation behavior of PHB/EPB blends, which have a higher thermal stability as measured by maximum decomposition temperature and residual weight, is probably due to crosslinking reactions of the epoxide groups in the EPB component with the carboxyl chain ends of PHB fragments during the degradation process, and the occurrence of such reactions can be assigned to the exothermic peaks in their DTA thermograms.  相似文献   

14.
3-methyl-1-(ethylacetyl)imidazolium chloride ([EtMIM]Cl), was synthesized for chitosan dissolution, and the dissolution and regeneration behaviors of chitosan in [EtMIM]Cl were thoroughly investigated. The solubility of chitosan in [EtMIM]Cl was measured at temperatures ranging from 40 °C to 110 °C, based on which the thermodynamic parameters of chitosan in [EtMIM]Cl were calculated. The polarizability and hydrogen bond accepting ability was determined by solvatochromic UV/vis spectroscopy. The regenerated chitosan from [EtMIM]Cl by adding methanol was characterized by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Density functional theory (DFT) computations were performed to study the interactions between [EtMIM]Cl and chitobiose. Five kinds of hydrogen bonds, C-H/O, O-H/O, O-H/Cl, C-H/Cl, N-H/Cl were found, suggesting strong interactions between [EtMIM]Cl and chitobiose. In particular, the oxygen atom and the active methylene group of carboxylic ester in [EtMIM]+, formed strong hydrogen bonding with chitobiose. The molecular simulation results indicated that both the Cl? anions and [EtMIM]+ cation played important roles in the chitosan dissolution process, by the disruption of native hydrogen bonds of chitosan.  相似文献   

15.
The oxidative polycondensation reaction conditions of (E)-3-amino-4-((3-bromophenyl)diazenyl)-1H-pyrazol-5-ol (Schiff base monomer) has been accomplished using NaOCl, and air O2 oxidants in an aqueous alkaline medium. The optical conductivity, dielectric and optical properties of synthesized poly(Schiff base) were examined. The magnitude of the refractive index decreases with increasing of photon energy up to about 2.5 eV, then refractive index of the poly(Schiff base) increases with increasing of photon energy. The E0 and Ed values of the poly(Schiff base) were found to be 5.34 and 9.22 eV, respectively. An indirect energy-gap value of the poly(Schiff base) was found to be 0.94±0.009 eV. A direct energy-gap value of the poly(Schiff base) was found to be 1.38±0.01 eV and 1.96±0.009 eV at first region and second region, respectively. Absorption coefficient K changes from 11.87 to 18.25 cm?1. In addition to fluorescence property of poly(Schiff base) was investigated. Finally, poly(Schiff base) and Schiff base monomer were tested for antibacterial activities against some bacteria.  相似文献   

16.
Uridine-5-’diphosphoglucose pyrophosphorylase (UTP α-D-glucose-l-phosphate uridylyltransferase, E.C. 2.7.7.9) (UGPase) was cloned from 16 potato cultivars(Solanum tuberosum L.) that differed in their ability to accumulate reducing sugars in cold storage (3 C) using RT-PCR. Two UGPase-alleles designatedas UgpA (minus a BamHl site) and UgpB (containing oneBamHl site), were present in most cultivars. Cultivars that were cold-resistant (CR) to sweetening demonstrated an UgpA:UgpB ratio favoring the UgpA allele (4:0 or 3:1), while cultivars that were cold-sensitive (CS) exhibited a predominance for the UgpB allele (1:3 or 0:4). Following cold-storage at 3 C for two months, the CR and CS clones accumulated 10.3 ± 2.1 and 31.2 ± 2.2 umol glucose/g FW, respectively. The glucose content and chip color between the CR and CS clones were significantly different at the 99% level of confidence. Staining for UGPase activity in nondenaturing polyacrylamide gels of proteins extracted from CS potatoes revealed up to three acidic isozymes of UGPase (i.e., UGP1, UGP2, UGP3) with UGP3 being the most abundant. Activity staining using CR cultivars demonstrated two additional isozymes of UGPase with greater electrophoretic mobility (more basic in charge) which were designated UGP4 and UGP5. The potential for using UGPase allelic ratios and/or UGPase isozymic patterns as a selective tool to screen segregating progeny in a potato breeding program for cold-sweetening-resistant germplasm is discussed.  相似文献   

17.
The objective of this study was to determine the effects of an alcoholic beverage (Toddy) and the equivalent quantity of ethanol on carbohydrate metabolism in utero. Female rats were exposed to Toddy from coconut palm (24.5 ml/kg body weight/day) and ethanol (0.52 ml/kg body weight/day) for 15 days before conception and throughout gestation. On the 19th day of gestation, hypoglycemia was seen in both the treated groups, but it was more in the Toddy-treated group. Synthesis of glycogen was elevated on exposure to ethanol/Toddy but its degradation was enhanced only in alcohol-exposed rats. Key enzymes of citric acid cycle and gluconeogenesis were inhibited on administration of both alcohol and Toddy. Activity of glycolytic enzymes were increased. Toddy seemed to potentiate the toxicity induced by alcohol, indicating the additive effects of congeners.  相似文献   

18.
The chemical control agent 3-(3-indolyl)butanoic acid, previously reported as a control agent for the bacterial wilt pathogen Ralstonia solanacearum, was shown to suppress the growth of green algae during hydroponic culture of tomato. The algicidal activity of the compound was effective at 10 μg/ml, completely preventing generation of green algae under non-shaded greenhouse conditions. The algicidal effect was mainly due to suppression of the growth of motile unicellular algal cells tentatively identified as Chlamydomonas spp., which are commonly occurring in the hydroponic solution and vigorously multiply to form an algal mat on the sponge supports. The compound has potential as a non-phytotoxic algicide for hydroponically cultured crop plants.  相似文献   

19.
Heterocyclic monoazo quinazolinone based azo dyes derived by the diazotization of 3-(4-aminophenyl)-2-phenylquinazolin-4(3H)-one with various phenyl pyrazolones based coupling components. All the heterocyclic azo dyes have been characterized by their percentage yield, UV-VIS spectroscopy, elemental analysis, IR spectroscopy, 1H NMR spectroscopy, and dyeing performance on silk, wool, nylon, and polyester fibers. All the dyes gave moderate to excellent fastness properties on each fiber. The main focus was to synthesize heterocyclic monoazo dyes that give good dyeing property along with pharmacological activity (anti bacterial and antifungal). Therefore, the synthesized compounds were examined for their antimicrobial activity at various concentrations using well-known Kirby-Bauer disk diffusion method.  相似文献   

20.
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