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Cao H  Lin R 《The protein journal》2008,27(3):163-169
Tristetraprolin/zinc finger protein 36 (TTP/ZFP36) binds and destabilizes some proinflammatory cytokine mRNAs. TTP-deficient mice develop a profound inflammatory syndrome due to excessive production of proinflammatory cytokines. TTP gene expression is induced by various factors including insulin, cinnamon, and green tea extracts. Previous studies have shown that TTP is highly phosphorylated in vivo and multiple phosphorylation sites are identified in human TTP. This study evaluated the potential protein kinases that could phosphorylate recombinant TTP in vitro. Motif scanning suggested that TTP was a potential substrate for various kinases. SDS-PAGE showed that in vitro phosphorylation of TTP with p42 and p38 MAP kinases resulted in visible electrophoretic mobility shift of TTP to higher molecular masses. Autoradiography showed that TTP was phosphorylated in vitro by GSK3b, PKA, PKB, PKC, but not Cdc2, in addition to p42, p38, and JNK. These results demonstrate that TTP is a substrate for a number of protein kinases in vitro.  相似文献   

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Fairmount 1 thorny” (“FM1 thorny”) (a Rosa multiflora Thunb ex. J. Murr.) and a thornless sport of “FM1 thorny” (“Fairmount 1” (“FM1”)) were established in vitro to investigate chimeral segregation under various levels of BA and to obtain a pure thornless rose. While the chimeral thornless sport was expected to segregate in vitro and yield both thorny and thornless plantlets, “FM1 thorny” was to yield only thorny plants. “FM1” segregated in vitro into its constituent genotypes and yielded thorny and thornless plantlets, suggesting that “FM1” is chimeral. “FM1 thorny” produced only thorny plants in vitro. These results indicate that the “FM1 thorny” clone was not chimeral (pure thorny) and that the thornless regenerates of “FM1” did not develop via somaclonal variation. There was a significant linear relationship between increasing BA concentration and the percentage of thorny plants. Among a population of 690 tissue culture derived plants from all the BA experiments, 6 plants were classified as pure thornless plants 1 year later.  相似文献   

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Nonthermal irreversible electroporation (NTIRE) is a new minimally invasive technique to treat cancer. It is unique because of its nonthermal mechanism of tumor ablation. Intracranial NTIRE procedures involve placing electrodes into the targeted area of the brain and delivering a series of short but intense electric pulses. The electric pulses induce irreversible structural changes in cell membranes, leading to cell death. We correlated NTIRE lesion volumes in normal brain tissue with electric field distributions from comprehensive numerical models. The electrical conductivity of brain tissue was extrapolated from the measured in vivo data and the numerical models. Using this, we present results on the electric field threshold necessary to induce NTIRE lesions (495–510 V/cm) in canine brain tissue using 90 50-μs pulses at 4 Hz. Furthermore, this preliminary study provides some of the necessary numerical tools for using NTIRE as a brain cancer treatment. We also computed the electrical conductivity of brain tissue from the in vivo data (0.12–0.30 S/m) and provide guidelines for treatment planning and execution. Knowledge of the dynamic electrical conductivity of the tissue and electric field that correlates to lesion volume is crucial to ensure predictable complete NTIRE treatment while minimizing damage to surrounding healthy tissue.  相似文献   

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Tau Promotes Neurodegeneration via DRP1 Mislocalization In Vivo   总被引:1,自引:0,他引:1  
B Duboff  J Götz  MB Feany 《Neuron》2012,75(4):618-632
Mitochondrial abnormalities have been documented in Alzheimer's disease and related neurodegenerative disorders, but the causal relationship between mitochondrial changes and neurodegeneration, and the specific mechanisms promoting mitochondrial dysfunction, are unclear. Here, we find that expression of human tau results in elongation of mitochondria in both Drosophila and mouse neurons. Elongation is accompanied by mitochondrial dysfunction and cell cycle-mediated cell death, which can be rescued in?vivo by genetically restoring the proper balance of mitochondrial fission and fusion. We have previously demonstrated that stabilization of actin by tau is critical for neurotoxicity of the protein. Here, we demonstrate a conserved role for actin and myosin in regulating mitochondrial fission and show that excess actin stabilization inhibits association of the fission protein DRP1 with mitochondria, leading to mitochondrial elongation and subsequent neurotoxicity. Our results thus identify actin-mediated disruption of mitochondrial dynamics as a direct mechanism of tau toxicity in neurons in?vivo.  相似文献   

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Candidosis has been attributed to C. albicans; however, infections caused by non-Candida albicans Candida (NCAC) species are increasingly being recognised. The ability of Candida to grow as a biofilm is an important feature that promotes both infection and persistence in the host. The biofilms’ activity is significant since high activity might be associated with enhanced expression of putative virulence factors, whilst in contrast low activity has previously been suggested as a mechanism for resistance of biofilm cells to antimicrobials. The aim of this study was to determine the metabolic activity of in vitro biofilms formed by different clinical isolates of NCAC species. The in situ total metabolic activity of C. parapsilosis, C. tropicalis and C. glabrata biofilms was determined using 2,3-(2-methoxy-4-nitro-5-sulphophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide (XTT) reduction assay, and the number of cultivable cells was also established by CFU (colony forming unit) counts. The biofilm structure was assessed by scanning electron microscopy (SEM). Results showed that total biofilm metabolic activity was species and strain dependent. C. glabrata exhibited the lowest biofilm metabolic activity despite having the highest number of biofilm cultivable cells. Similarly, the metabolic activity of resuspended C. glabrata biofilm and planktonic cells was lower than that of the other species. This study demonstrates the existence of intrinsic activity differences amongst NCAC species, which could have important implications in terms of species relative virulence. Furthermore, the absence of an obvious correlation, between cultivable cells number and total biofilm activity, raises the question about which parameter is the most appropriate for the in vitro assessment of biofilms and their potential clinical significance.  相似文献   

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Xu R  Shang N  Li P 《Anaerobe》2011,17(5):226-231
The aim of the study was to purify the exopolysaccharides (EPS) produced from Bifidobacterium animalis RH, which was isolated from the feces of Bama centenarians in Guangxi of China, and evaluate their antioxidant activities in vitro and in vivo. 2 fractions, a neutral EPS fraction (EPSa) and an acidic EPS fraction (EPSb), were obtained and compared for antioxidative activity. In vitro, they both showed remarkable inhibition effect on lipid peroxidation and strong DPPH radical scavenging activity, hydroxyl radical scavenging activity, superoxide radical scavenging activity, in which the last two were measured by the electron spin resonance (ESR). In vivo, EPSa and EPSb were orally administrated for 30 days in a d-galactose induced aged mice model. As results, they both could significantly increase the activities of SOD, CAT and total antioxidant capacity (TAOC) in serums and glutathione GST in livers. They also could inhibit significantly the formation of MDA in serums and livers, and reduce the activity of MAO and lipofuscin accumulation in mice brain. Moreover, EPSb exhibited much higher antioxidant activities than EPSa in vitro and in vivo. The results suggested that EPS fractions of Bifidobacterium animalis RH had direct and potent antioxidant activities.  相似文献   

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The T-lymphocyte pool can be subdivided into naïve (Tn), effector memory (Tem), and central memory (Tcm) T cells. In this study, we characterized in vitro short-term cultured anti-tumor human T lymphocytes generated by lentiviral transduction with an anti-tumor antigen TCR vector. Within 2 weeks of in vitro culture, the cultured T cells showed a Tcm-like phenotype illustrated by a high percentage of CD62L and CD45RO cells. When the cells were sorted into populations that were CD45RO+/CD62L-(Tem), CD45RO+/CD62L+(Tcm), or CD45ROlow/CD62L+(Tn) and co-cultured with antigen-matched tumor lines, the magnitude of cytokine release from these populations for IFNγ (Tn < Tcm < Tem) and IL-2 (Tn > Tcm > Tem) mimicked the types of immune cell responses observed in vivo. In comparing cell-mediated effector function, Tn were found to be deficient (relative to Tcm and Tem) in the ability to form conjugates with tumor cells and subsequent lytic activity. Moreover, analysis of the gene expression profiles of the in vitro cultured and sorted T-cell populations also demonstrated patterns consistent with their in vivo counterparts. When Tcm and Tem were tested for the ability to survive in vivo, Tcm displayed significantly increased engraftment and persistence in NOD/SCID/γc?/? mice. In general, a large percentage of in vitro generated anti-tumor T lymphocytes mimic a Tcm-like phenotype (based on phenotype, effector function, and increased persistence in vivo), which suggests that these Tcm-like cultured T cells may be optimal for adoptive immunotherapy.  相似文献   

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A major obstacle to native orchid production is difficulty in seed germination. Culture media and light effects on seed germination of Calopogon tuberosus var. tuberosus, a native orchid with horticultural potential, were studied. Culture media included Knudson C, Malmgren modified terrestrial orchid, and PhytoTechnology orchid seed sowing. Effects of 8 weeks continual darkness, 8 weeks 16-h photoperiod, 2 weeks dark followed by 6 weeks 16-h photoperiod, 4 weeks dark followed by 4 weeks 16-h photoperiod, and 6 weeks dark followed by 2 weeks 16-h photoperiod were examined. Percent seed germination was highest on Knudson C after 8 weeks culture; however, seedling development was enhanced on PhytoTechnology seed sowing medium during 8 weeks culture under a 16-h photoperiod. This suggests that while KC and darkness promoted seed germination, P723 and light enhanced further seedling development. Seedlings of C. tuberosus readily acclimated to greenhouse conditions.  相似文献   

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In vitro haploid and dihaploid production via unfertilized ovule culture   总被引:2,自引:0,他引:2  
Haploids and doubled haploids are very important in plant breeding, enabling the time needed to produce homozygous lines to be shortened compared with conventional breeding. In the present review, emphasis is given to haploid induction through unfertilized ovule/ovary culture. Attention is given to induction of haploid plants from female gametophyte culture through analysis of factors in the processes of gynogenesis, including genotype selection, stage of ovule development, pretreatment, and culture media containing nutritional components and phytohormones. The gynogenetic approach may be of great value in discovering novel genetic recombinations. Application of double haploids in genetics and plant breeding is also highlighted. This review also identifies some existing knowledge gaps where work may increase the efficiency of this process in different plant species.  相似文献   

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Erythropoietin (Epo) is a hematopoietic factor, which stimulates proliferation and differentiation of erythroid precursor cells. Epo also functions as a neuroprotective factor and protects neurons from ischemic damage. Recently a 17-mer peptide sequence (Epopeptide AB) in Epo (AEHCSLNENITVPDTKV) with a neuroprotective function was reported. In this study, we showed in vivo evidence that Epopeptide AB protected neurons from ischemic damage at similar dose compared to Epo. Epopeptide AB could not stimulate the proliferation of Epo-dependent growing murine myeloid Ep-FDC-P2 cells and also did not compete the proliferative function of Epo on these cells. Together with these results, Epopeptide AB did not transduce signals through direct binding to the known Epo receptor on hematopoietic cells but has neuroprotective activity against ischemia. These authors contributed equally to this paper  相似文献   

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Force–Velocity Curves of Motor Proteins Cooperating In Vivo   总被引:1,自引:0,他引:1  
Motor proteins convert chemical energy into work, thereby generating persistent motion of cellular and subcellular objects. The velocities of motor proteins as a function of opposing loads have been previously determined in vitro for single motors. These single molecule “force–velocity curves” have been useful for elucidating motor kinetics and for estimating motor performance under physiological loads due to, for example, the cytoplasmic drag force on transported organelles. Here we report force–velocity curves for single and multiple motors measured in vivo. Using motion enhanced differential interference contrast (MEDIC) movies of living NT2 (neuron-committed teratocarcinoma) cells at 37°C, three parameters were measured—velocity (v), radius (a), and effective cytoplasmic viscosity (η′)—as they applied to moving vesicles. These parameters were combined in Stokes’ equation, = 6πaη′v, to determine the force, F, required to transport a single intracellular particle at velocity, v. In addition, the number of active motors was inferred from the multimodal pattern seen in a normalized velocity histogram. Using this inference, the resulting in vivo force–velocity curve for a single motor agrees with previously reported in vitro single motor force–velocity curves. Interestingly, however, the curves for two and three motors lie significantly higher in both measured velocity and computed force, which suggests that motors can work cooperatively to attain higher transport forces and velocities. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

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