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1.
Dietary intakes of tomatoes and tomato products containing lycopene have been shown to be associated with decreased risk of chronic diseases such as cancer and cardiovascular diseases in numerous studies. Serum and tissue lycopene levels have also been inversely related to the risk of lung and prostate cancers. Lycopene functions as a very potent antioxidant, and this is clearly a major important mechanism of lycopene action. In this regard, lycopene can trap singlet oxygen and reduce mutagenesis in the Ames test. However, evidence is accumulating for other mechanisms as well. Lycopene at physiological concentrations can inhibit human cancer cell growth by interfering with growth factor receptor signaling and cell cycle progression specifically in prostate cancer cells without evidence of toxic effects or apoptosis of cells. Studies using human and animal cells have identified a gene, connexin 43, whose expression is upregulated by lycopene and which allows direct intercellular gap junctional communication (GJC). GJC is deficient in many human tumors and its restoration or upregulation is associated with decreased proliferation. The combination of low concentrations of lycopene with 1,25-dihydroxyvitamin D3 exhibits a synergistic effect on cell proliferation and differentiation and an additive effect on cell cycle progression in the HL-60 promyelocytic leukemia cell line, suggesting some interaction at a nuclear or subcellular level. The combination of lycopene and lutein synergistically interact as antioxidants, and this may relate to specific positioning of different carotenoids in membranes. This review will focus on the growing body of evidence that carotenoids have unexpected biologic effects in experimental systems, some of which may contribute to their cancer preventive properties in models of carcinogenesis. Consideration of solubility in vitro, comparison with doses achieved in humans by dietary means, interactions with other phytochemicals, and other potential mechanisms such as stimulation of xenobiotic metabolism, inhibition of cholesterogenesis, modulation of cyclooxygenase pathways, and inhibition of inflammation will be considered. This review will point out areas for future research where more evidence is needed on the effects of lycopene on the etiology of chronic disease.  相似文献   

2.
The levels of endogenous phytohormones and respiratory rate in nine sorts of flowers such as Cymbidium faberi Rolfe, Nopalxochia ackermannii Kunth and others were investigated both at full bloom and senescence and meanwhile the effect of exogenous phytohormones on prolonging the blossoms and promoting ethylene production were tested. There is a high content of endogenous ethylene in all the long-lived flowere, about 3–16 folds higer than the short-lived ones. There is a high level of ABA at full blooming flowers of short-lived flowers, in which there is no or only some cytokinins in it, but the ratio of CTK (6BA+zeatin)/ABA is smaller(l.7). The endogenous ABA reached a much higher level at senescence in all nine sorts of flowers, so it is reasonable to consider that it is ABA which plays an important role of regulation in controlling flower's senescence. There is a much higher level of GA3 and zeatin in the long-lived flowers which is not demonstrated in the shortlived ones. The respiratory rate is one of the factors controtling the longevity of flowers, but it does not play a decided role. Application of 6BA and zeatin prolongs distinctly orchid’s longevity, however exogenous IAA through the promotive action on ethylene production, evidently extends the longevity of the flowers of the Nopalxochia ackermannii Kunth.  相似文献   

3.
Histologic sections of arteries can be used to generate three-dimensional (3D) geometric models and identify structural constituents. However, geometric distortions are introduced by fixation, embedding and sectioning; distortions which can, for example, lead to errors in stresses predicted by finite element models. We developed a method to measure and correct for distortions caused by acrylic processing and applied it to intact, healthy porcine coronary arteries. Micro-computed tomography was used to image arteries in the fresh and embedded states. Tissue blocks were sectioned, stained and imaged using a light microscope. Each section contained four registration marks used to determine strains introduced by sectioning and staining. Using these three image sets, 3D geometric models were generated and distortions were measured. Fixation, processing, and embedding resulted in shrinkage of 6.4+/-2.3% axially and 35.4+/-5.0% in mean cross-sectional area (n=5). Shrinkage in a cross section was well characterized by a uniform, equibiaxial strain. Sectioning and staining resulted in additional compressive strains in the sectioning direction of 0.067+/-0.011 and, in the direction perpendicular to sectioning, of 0.023+/-0.005 (n=5). These strains are assumed uniform and form the basis for correcting section geometry. Reconstructions using corrections for sectioning and shrinkage-related distortions had errors of 1.6+/-0.5% (n=5) and 4.0+/-1.7% (n=5), respectively.  相似文献   

4.
C-banding patterns of the karyotypes of two closely related wild flax species, Linum austriacum L. (2n = 18) and Linum grandiflorum Desf. (2n = 16), were studied. The karyotypes of both species were similar in the chromosome morphology and size. In each species, metacentric and acrocentric chromosomes (1.7-4.3 microns) and one satellite chromosome were observed. In the karyotypes of the species studied, all homologous chromosome pairs were identified, and quantitative ideograms were constructed. Eight chromosome pairs in the two species had similar C-banding patterns. A low level of intraspecific polymorphism in the intercalary and telomeric C-bands was shown in both species. The results indicate that the genomes of two flax species originated from one ancestral genome with the main chromosome number of 8 or 9. Apparently, the doubling of chromosome number or loss of one chromosome with subsequent redistribution of the chromosome material in the ancestral form resulted in the divergence into two species, L. austriacum L. and L. grandiflorum Desf. A considerable similarity of chromosomes in these species provides evidence for their close phylogenetic relatedness, which makes it possible to place them in one section within the Linum genus.  相似文献   

5.
The correlative analysis of diurnal rhythms of cell number and adenylate cyclase cellular activity was performed in the thymus, spleen and peripheral blood of Swiss mice, intact or thymectomized at the age of 3 months. The existence of somehow synchronized diurnal rhythms of cAMP exchange and cell recirculation was found in the peripheral lymphocyte pool and in the thymus. Diurnal rhythm of cAMP synthesis in peripheral lymphocytes was regulated by the thymus. Thymectomy led to desynchronization of recirculating processes and cyclic nucleotide metabolism in immunocompetent cells.  相似文献   

6.
The metabolism of nuclear phospholipid acyl components of liver in uneven-aged rats was studied in vitro under different dietary fat implications. The activity of phospholipases A1 and A2 in the nuclei was found to sharply increase in animals pretreated with excess of fat. The incorporation of labelled palmitic, oleic, linoleic and arachidonic acid into nuclear phospholipids is under control of age and diet manipulations. The observed changes in the level of fatty acids metabolism are more pronounced in cell nuclei of the young rat liver. The lipid composition of cell nuclei in the test 3-month old animals does not differ from that of the control animals. At the same time dietary implications induce deep changes in the composition of nuclear lipids in 24-months old animals.  相似文献   

7.
Effects of catecholamines (CA) and the character of interaction of CA and NO in regulation of apoptosis were studied in vasopressinergic (VP-ergic) neurons of supraoptic (SON) and paraventricular (PVN) nuclei of rat pups in early postnatal ontogenesis. To study role of CA in regulation of programmed cell death in SON and PVN in the course of embryonal development, pregnant female rats were intraperitoneally injected daily from the 13th to the 20th day with αMPT—a blocker of CA synthesis. The second group of pregnant rats was injected from the 13th to the 20th day with the same volume of saline. The third group was composed of intact animals. The born rat pups were sacrificed at the 3rd and 15th days of life. Caspase 9, Bcl-2, tyrosine hydroxylase, and neuronal NO-synthase (nNOS) in SON and PVN neurons were revealed immunohistochemically, and the amount of immunoreactive substance in neuronal bodies was estimated using the computerized digital analyzer of TV image and Video Test software. Caspase-9 was shown to play an important role in postnatal formation of cellular composition of hypothalamic nonapeptidergic centers by leading to initiation of apoptosis and rejection of “useless” postmitotic SON and PVN neurons. Survival of “useless” nonapeptidergic neurons in early postnatal ontogenesis seems to be connected with antiapoptotic action of Bcl-2. Death of postmitotic neurons, and therefore formation of cellular composition begins earlier and, accordingly, is completed earlier in SON, in which neurons were noted to have a considerable decrease of the caspase-9 expression and, therefore, also a decrease of intensity of neuronal death via caspase-9-dependent pathway. In PVN, neurons continue to die also at the 15th day of rat life, i.e., almost two weeks later than in SON. The observed high correlation between the content of nNOS, caspase-9, and Bcl-2 in the SON and PVN neurons of intact rats of both age groups allows suggesting participation of NO in realization of apoptosis in the course of early postnatal development. The increase of nNOS expression in hypothalamic neurons as a result of disturbances in CA-ergic innervation in embryogenesis might be a possible cause of the long preserved enhancement of expression of apoptosis signal proteins. It can be suggested that CA participate in morphogenesis of hypothalamic neurons by increasing expression of nNOS in neurons and thereby affecting expression of apoptotic proteins.  相似文献   

8.
The mammalian target of rapamycin (mTOR) is a Ser/Thr kinase that plays essential roles in the regulation of a wide array of growth-related processes such as protein synthesis, cell sizing, and autophagy. mTOR forms two functionally distinct complexes, termed the mTOR complex 1 (mTORC1) and 2 (mTORC2); only the former of which is inhibited by rapamycin. Based on the similarity between the cellular responses caused by rapamycin treatment and by nutrient starvation, it has been widely accepted that modulation in the mTORC1 activity in response to nutrient status directs these cellular responses, although direct evidence has been scarce. Here we report isolation of hyperactive mutants of mTOR. The isolated mTOR mutants exhibited enhanced kinase activity in vitro and rendered cells refractory to the dephosphorylation of the mTORC1 substrates upon amino acid starvation. Cells expressing the hyperactive mTOR mutant displayed larger cell size in a normal growing condition and were resistant to cell size reduction and autophagy induction in an amino acid-starved condition. These results indicate that the activity of mTORC1 actually directs these cellular processes in response to nutrient status and confirm the biological functions of mTORC1, which had been proposed solely from loss-of-function analyses using rapamycin and (molecular)genetic techniques. Additionally, the hyperactive mTOR mutant did not induce cellular transformation of NIH/3T3 cells, suggesting that concomitant activation of additional pathways is required for tumorigenesis. This hyperactive mTOR mutant will be a valuable tool for establishing physiological consequences of mTOR activation in cells as well as in organisms.  相似文献   

9.
基于GIS的稻田蜘蛛混合种群发生分析   总被引:1,自引:0,他引:1  
在地理信息系统的支持下 ,对中国稻区 117个样点蜘蛛物种数与个体数进行空间插值 ,获得稻田蜘蛛混合种群数量专题地图和个体数量发生专题地图 .根据所得专题地图 ,分析了不同水稻种植区蜘蛛种群发生以及不同稻区的生态特征 .研究结果如下 :在北纬 35 .5°以南的水稻种植区域 ,蜘蛛种群与个体发生量较高 ,种群一般在 13种以上 ,个体数一般在每 10 0丛禾 10 0头以上 ;在北纬 35 .5°以北的水稻种植区域种群一般在 11种以下 ,个体数一般在每 10 0丛禾 47头以下 ;在北纬 35 .5°以南的水稻种植区域的年降雨量、年无霜期和 7月平均温度要高于在北纬 35 .5°以北的水稻种植区域 .在北纬 35 .5°以南的水稻种植区域的年日照时数要低于在北纬 35 .5°以北的水稻种植区域 .  相似文献   

10.
11.
The content of cholesterol, total and individual phospholipids, fatty acid composition, level of lipid peroxidation, as well as viscosity of lipid phase of synaptic membranes isolated from the cerebral cortex were estimated in experiments on adult and old male rats. The content of cholesterol and cholesterol phospholipids ratio were found to increase with age. The total content of phospholipids remained unchanged during ageing, while their composition varied. An increase in the content of minor forms of phospholipids, i.e. phosphatidylserine and phosphatidylinositol, in the sphingomyelin/phosphatidyl ethanolamine ratio and, especially, in the content of lysophosphatidylcholine was found in old vs adult rats. No age-related changes were found in the viscosity of the lipid phase of synaptic membranes with purene used as a fluorescent probe.  相似文献   

12.
13.
Summary Nitrate reductase activity of the terminal bud of tea shoots was greater than that in mature leaves, and exhibited greater activity in triethanolamine HCl–KOH buffer than in phosphate or Clark and Lubs buffers. There was some correlation between yield characteristics of different tea clones and the level of nitrate reductase activity in the terminal bud, and mulching of plants was found to cause a significant increase in activity of the enzyme.  相似文献   

14.
The contents of dopamine, serotonin, and noradrenaline in rat fetuses developing under the conditions of their deficiency induced by administration of alpha-methyl-para-tyrosine to females during 11th to 16th or 20th day of pregnancy and in fetuses, whose mothers were given saline at the same time, were determined using HPLC with subsequent electrochemical detection. Administration of alpha-methyl-para-tyrosine led to decreased levels of dopamine and noradrenaline in the areas of migration of GnRH-neurons in fetuses on days 17 and 21 of prenatal development. The concentration of serotonin remained unchanged, except in the head nasal area in males on day 21. The areas of interaction between the brain catecholaminergic systems and migrating and differentiating GnRH-neurons were determined by double immunohistochemical labeling. Close topographical location of GnRH-immunoreactive neurons and tyrosine hydroxylase-immunoreactive in the area of nucleus accumbens on days 17 and 20, as well as in the median eminence on day 20. The GnRH concentration in the caudal areas of migration of GnRH-neurons under the normal conditions and in the case of catecholamine deficiency was determined using radioimmunoassay. After administration of alpha-methyl-para-tyrosine the GnRH concentration in the anterior hypothalamus decreased in females. The data obtained suggest the involvement of catecholamines in the regulation of development of GnRH-Neurons during prenatal development. In addition, the adequacy and efficiency of the used model of catecholamine deficiency for studying the development of such neurons was confirmed.  相似文献   

15.
Shapes of curves of pH-dependence of reactions   总被引:14,自引:14,他引:0  
A simple case is considered in which the rate of a two-step reaction depends on pH because the intermediate formed in the first step has to gain (or lose) a proton before it can react in the second step, and in which the rate-determining step therefore changes with pH. The curves of reaction rate against pH are shown to be symmetrical, and the sharpest peak possible has a width at half its height of 1.53pH units, i.e. of 2log(3+2 radical2). Any particular curve for this situation proves to be identical with a curve that could be generated for the pH-dependence of a single-step reaction in which the rate is proportional to the concentration of a particular ionic form of a reactant. Curves for the latter situation, however, can have forms impossible for the former case in which the rate-determining step changes, but only if the protonations that activate and deactivate the reactant are co-operative. The peak can then become even sharper, and its width at half its height can fall to 1.14pH units, i.e. to 2log(2+ radical3).  相似文献   

16.
目的:分析激光联合注射曲安奈德治疗婴幼儿血管瘤的疗效。方法:将120例处于增殖期血管瘤患儿分成观察组和对照组各60例,观察组给予激光联合注射曲安奈德治疗,对照组采用激光治疗,比较两组患者的治疗疗效。结果:观察组和对照组的总有效率分别为96.7%和66.7%,两组比较具有显著差异,P〈0.05;对于表浅病灶,观察组治疗的有效率为96.8%,对照组为84.8%,两组之间无差异,P〉0.05;对于深部病灶,观察组和对照组的总有效率分别为96.6%和44.4%,具有显著差异(P〈0.05)。结论:激光联合注射曲安奈德治疗婴幼儿血管瘤具有较好的疗效,尤其对深部增殖期的血管瘤具有较好的效果,适合在临床推广应用。  相似文献   

17.
Fine-tuning of insulin secretion from pancreatic beta-cells participates in blood glucose homeostasis. Defects in this process can lead to chronic hyperglycemia and diabetes mellitus. Several proteins controlling insulin exocytosis have been identified, but the mechanisms regulating their expression remain poorly understood. Here, we show that two non-coding microRNAs, miR124a and miR96, modulate the expression of proteins involved in insulin exocytosis and affect secretion of the beta-cell line MIN6B1. miR124a increases the levels of SNAP25, Rab3A and synapsin-1A and decreases those of Rab27A and Noc2. Inhibition of Rab27A expression is mediated by direct binding to the 3'-untranslated region of Rab27A mRNA. The effect on the other genes is indirect and linked to changes in mRNA levels. Over-expression of miR124a leads to exaggerated hormone release under basal conditions and a reduction in glucose-induced secretion. miR96 increases mRNA and protein levels of granuphilin, a negative modulator of insulin exocytosis, and decreases the expression of Noc2, resulting in lower capacity of MIN6B1 cells to respond to secretagogues. Our data identify miR124a and miR96 as novel regulators of the expression of proteins playing a critical role in insulin exocytosis and in the release of other hormones and neurotransmitters.  相似文献   

18.
The present investigation deals with the effect of testosterone on each of the tissue components of the bursa of Fabricius: the endodermal epithelium, the mesenchyme, and the hemopoietic stem cells. Tissue combination experiments between testosterone-treated endoderm and normal mesenchyme and vice versa have shown that the androgen damages irreversibly the bursal epithelium. The latter is not seeded by hemopoietic stem cells and cannot undergo follicle formation when treated with high doses of testosterone. This occurs even if it is associated with a nontreated bursal mesenchyme. On the contrary, associations of testosterone-treated mesenchyme with normal endoderm result in normal bursa histogenesis. By using an original test of viability for lymphoid cells based on the application of the quail-chick marker system, we demonstrate that disappearance of hemopoietic cells in the endoderm results from their expulsion from the bursa and not from their death in situ. The conspicuous effect of testosterone on the bursa of Fabricius can be related to the levels of androgen receptors found in the organ. Typical cytosol androgen receptors are demonstrated in both bursal endoderm and mesoderm, although the amount in the former is higher. The concentration of binding sites in the bursa is >10 times higher than that in other organs such as lung and small intestine whose development is not affected by testosterone, contrasting with glucocorticosteroid receptor (measured by labeling with dexamethasone) found in the same concentration in all tissues.  相似文献   

19.
20.
As it is universally recognized, the population is a sound criteria of the environment quality. The most reliable method to evaluate genetic processes in a population under the condition of the environmental pollution is genetic monitoring, a survey of dynamic parameters of genetic load. An evaluation of genetical safety of an urbanized area of a city is represented in this article. The parameters of genetic load like congenital malformations and multifactorial diseases have been used in the models of monitoring. The analysis and comparison of disease frequencies in Kharkiv Dzerzhinsky District, in other European populations and in regional rural districts with various levels of production have been made.  相似文献   

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