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31.
The uptake and K(+)-evoked (40 mM) release of 3H-norepinephrine (3H-NE) in mesodiencephalic synaptosomes of adult and senescent rats and the effect of N-acetylaspartic acid (NAA) on these processes have been studied. It has been shown that the uptake of 3H-NE by old rats is reduced considerably. The K(+)-evoked release of 3H-NE from rats synaptosomes is significantly decreased in aged rats. In the presence of 10(-4)-3.10(-3) M NAA the uptake of 3H-NE by adult and senescent rats synaptosomes remains unchanged. In these concentrations NAA inhibits the K(+)-evoked release of 3H-NE from synaptosomes of adult rats, but it exerts no effect on this process in senescent rats. 相似文献
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33.
Cell-to-cell and phloem-mediated transport of potato virus X. The role of virions 总被引:13,自引:1,他引:12
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Movement-deficient potato virus X (PVX) mutants tagged with the green fluorescent protein were used to investigate the role of the coat protein (CP) and triple gene block (TGB) proteins in virus movement. Mutants lacking either a functional CP or TGB were restricted to single epidermal cells. Microinjection of dextran probes into cells infected with the mutants showed that an increase in the plasmodesmal size exclusion limit was dependent on one or more of the TGB proteins and was independent of CP. Fluorescently labeled CP that was injected into epidermal cells was confined to the injected cells, showing that the CP lacks an intrinsic transport function. In additional experiments, transgenic plants expressing the PVX CP were used as rootstocks and grafted with nontransformed scions. Inoculation of the PVX CP mutants to the transgenic rootstocks resulted in cell-to-cell and systemic movement within the transgenic tissue. Translocation of the CP mutants into sink leaves of the nontransgenic scions was also observed, but infection was restricted to cells close to major veins. These results indicate that the PVX CP is transported through the phloem, unloads into the vascular tissue, and subsequently is transported between cells during the course of infection. Evidence is presented that PVX uses a novel strategy for cell-to-cell movement involving the transport of filamentous virions through plasmodesmata. 相似文献
34.
A GFP-MAP4 reporter gene for visualizing cortical microtubule rearrangements in living epidermal cells 总被引:15,自引:7,他引:8
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J Marc CL Granger J Brincat DD Fisher Th Kao AG McCubbin RJ Cyr 《The Plant cell》1998,10(11):1927-1940
Microtubules influence morphogenesis by forming distinct geometrical arrays in the cell cortex, which in turn affect the deposition of cellulose microfibrils. Although many chemical and physical factors affect microtubule orientation, it is unclear how cortical microtubules in elongating cells maintain their ordered transverse arrays and how they reorganize into new geometries. To visualize these reorientations in living cells, we constructed a microtubule reporter gene by fusing the microtubule binding domain of the mammalian microtubule-associated protein 4 (MAP4) gene with the green fluorescent protein (GFP) gene, and transient expression of the recombinant protein in epidermal cells of fava bean was induced. The reporter protein decorates microtubules in vivo and binds to microtubules in vitro. Confocal microscopy and time-course analysis of labeled cortical arrays along the outer epidermal wall revealed the lengthening, shortening, and movement of microtubules; localized microtubule reorientations; and global microtubule reorganizations. The global microtubule orientation in some cells fluctuates about the transverse axis and may be a result of a cyclic self-correcting mechanism to maintain a net transverse orientation during cellular elongation. 相似文献
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36.
Peripheral alpha1,3-fucosylation of glycans occurs by the action of either
one of five different alpha1,3-fucosyltransferases (Fuc-Ts) cloned to date.
Fuc-TVI is one of the alpha1,3-fucosyltransferases which is capable to
synthesize selectin ligands. The major alpha1, 3- fucosyltransferase
activity in human plasma is encoded by the gene for fucosyltransferase VI,
which presumably originates from liver cells. While the sequence,
chromosomal localization, and kinetic properties of Fuc-TVI are known,
immunocytochemical localization and trafficking studies have been
impossible because of the lack of specific antibodies. Here we report on
the development and characterization of a peptide-specific polyclonal
antiserum monospecific to Fuc-TVI and an antiserum to purified soluble
recombinant Fuc-TVI crossreactive with Fuc-TIII and Fuc-TV. Both antisera
were applied for immunodetection in stably transfected CHO cells expressing
the full-length form of this enzyme (CHO clone 61/11). Fuc-TVI was found to
be a resident protein of the Golgi apparatus. In addition, more than 30% of
cell-associated and released enzyme activity was found in the medium.
Maturation and release of Fuc-TVI was analyzed in metabolically labeled CHO
61/11 cells followed by immunoprecipitation. Fuc-TVI occurred in two forms
of 47 kDa and 43 kDa bands, while the secreted form was detected as a 43
kDa. These two different intracellular forms arose by posttranslational
modification, as shown by pulse-chase experiments. Fuc-TVI was released to
the supernatant by proteolytic cleavage as a partially endo-H resistant
glycoform.
相似文献
37.
JC de Mauroy HR Weiss AG Aulisa L Aulisa JI Brox J Durmala C Fusco TB Grivas J Hermus T Kotwicki G Le Blay A Lebel L Marcotte S Negrini L Neuhaus T Neuhaus P Pizzetti L Revzina B Torres PJM Van Loon E Vasiliadis M Villagrasa M Werkman M Wernicka MS Wong F Zaina 《Scoliosis》2010,5(1):1-15
Abstract
Thoracic hyperkyphosis is a frequent problem and can impact greatly on patient's quality of life during adolescence. This condition can be idiopathic or secondary to Scheuermann disease, a disease disturbing vertebral growth. To date, there is no sound scientific data available on the management of this condition. Some studies discuss the effects of bracing, however no guidelines, protocols or indication's of treatment for this condition were found. The aim of this paper was to develop and verify the consensus on managing thoracic hyperkyphosis patients treated with braces and/or physiotherapy.Methods
The Delphi process was utilised in four steps gradually modified according to the results of a set of recommendations: we involved the SOSORT Board twice, then all SOSORT members twice, with a Pre-Meeting Questionnaire (PMQ), and during a Consensus Session at the SOSORT Lyon Meeting with a Meeting Questionnaire (MQ).Results
There was an unanimous agreement on the general efficacy of bracing and physiotherapy for this condition. Most experts suggested the use of 4-5 point bracing systems, however there was some controversy with regards to physiotherapeutic aims and modalities.Conclusion
The SOSORT panel of experts suggest the use of rigid braces and physiotherapy to correct thoracic hyperkyphosis during adolescence. The evaluation of specific braces and physiotherapy techniques has been recommended. 相似文献38.
Although prey species typically respond to the most limiting factors at coarse spatiotemporal scales while addressing biological requirements at finer scales, such behaviour may become challenging for species inhabiting human altered landscapes. We investigated how woodland caribou, a threatened species inhabiting North-American boreal forests, modified their fine-scale movements when confronted with forest management features (i.e. clearcuts and roads). We used GPS telemetry data collected between 2004 and 2010 on 49 female caribou in a managed area in Québec, Canada. Movements were studied using a use – availability design contrasting observed steps (i.e. line connecting two consecutive locations) with random steps (i.e. proxy of immediate habitat availability). Although caribou mostly avoided disturbances, individuals nonetheless modulated their fine-scale response to disturbances on a daily and annual basis, potentially compromising between risk avoidance in periods of higher vulnerability (i.e. calving, early and late winter) during the day and foraging activities in periods of higher energy requirements (i.e. spring, summer and rut) during dusk/dawn and at night. The local context in which females moved was shown to influence their decision to cross clearcut edges and roads. Indeed, although females typically avoided crossing clearcut edges and roads at low densities, crossing rates were found to rapidly increase in greater disturbance densities. In some instance, however, females were less likely to cross edges and roads as densities increased. Females may then be trapped and forced to use disturbed habitats, known to be associated with higher predation risk. We believe that further increases in anthropogenic disturbances could exacerbate such behavioural responses and ultimately lead to population level consequences. 相似文献
39.
Intrinsic oxidative stress through enhanced production of reactive oxygen species (ROS) in prostate and other cancers may contribute to cancer progression due to its stimulating effect on cancer growth. In this study, we investigate differential responses to exogenous oxidative stimuli between aggressive prostate cancer and normal cell lines and explore potential mechanisms through interactions between cytotoxicity, cellular ROS production and oxidative DNA damage. The circular, multi-copy mitochondrial DNA (mtDNA) is used as a sensitive surrogate to oxidative DNA damage. We demonstrate that exogenous H(2)O(2) induces preferential cytotoxicity in aggressive prostate cancer than normal cells; a cascade production of cellular ROS, composed mainly of superoxide (O(2)(-)), is shown to be a critical determinant of H(2)O(2)-induced selective toxicity in cancer cells. In contrast, mtDNA damage and copy number depletion, as measured by a novel two-phase strategy of the supercoiling-sensitive qPCR method, are very sensitive to exogenous H(2)O(2) exposure in both cancer and normal cell lines. Moreover, we demonstrate for the first time that the sensitive mtDNA damage response to exogenous H(2)O(2) is independent of secondary cellular ROS production triggered by several ROS modulators regardless of cell phenotypes. These new findings suggest different mechanisms underpinning cytotoxicity and DNA damage induced by oxidative stress and a susceptible phenotype to oxidative injury associated with aggressive prostate cancer cells in vitro. 相似文献
40.
Florigio Lista Frans AG Reubsaet Riccardo De Santis Rene R Parchen Ad L de Jong Jasper Kieboom Anton L van der Laaken Ingrid AI Voskamp-Visser Silvia Fillo Hugo-Jan Jansen Jan Van der Plas Armand Paauw 《BMC microbiology》2011,11(1):1-11