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排序方式: 共有285条查询结果,搜索用时 31 毫秒
1.
Duygu Findik Qizhong Song Hiroyoshi Hidaka Martin Lavin 《Journal of cellular biochemistry》1995,57(1):12-21
In addition to a role for de novo protein synthesis in apoptosis we have previously shown that activation of a protein phosphatase or loss of activity of a kinase is also important in radiation-induced apoptosis in human cells [Baxter, and Lavin (1992): J Immunol 148:149–1954]. We show here that some inhibitors of protein kinases exacerbate radiation-induced apoptosis in the human cell line BM13674. The specific protein kinase A inhibitor isoquinoline sulfonamide (20 μM) gave rise to significantly increased levels of apoptosis at 2–6 h postirradiation compared to values after radiation exposure only. The same concentration of isoquinolinesulfonamide, which was effective in increasing apoptosis, reduced activity markedly. A 66% inhibition of cyclic AMP-dependent protein kinase A activity occurred in unirradiated cells at this concentration of H89 and activity was reduced to 58% in irradiated cells. Calphostin C, a specific inhibitor of protein kinase C, at a concentration of 0.1 μM, which caused 68% inhibition of enzyme activity in irradiated cells, failed to enhance the level of radiation-induced apoptosis. Other kinase inhibitors did not lead to an additional increase in apoptosis over and above that observed after irradiation. The results obtained here provide further support for an important role for modification of existing proteins during radiation-induced apoptosis. 相似文献
2.
Micrococcal nuclease was used as a probe to study chromatin structure in control and ataxia-telangiectasia cells. The rate and extent of release of acid-soluble nucleotide was similar in both cell types. Production of mono- and oligonucleosomes by micrococcal nuclease as determined by gel electrophoresis also failed to reveal differences in chromatin structure between control and ataxia-telangiectasia cells. Radiation exposure did not significantly alter the kinetics of digestion. These results indicate that there are no gross alterations in chromatin structure in ataxia-telangiectasia cells. 相似文献
3.
A marked increase in sensitivity to bleomycin was observed in two ataxia telangiectasia (AT) lymphoblastoid cell lines compared to that in cell lines from two normal individuals. This sensitivity was obtained at two different concentrations of bleomycin. While normal cells showed a rapid recovery of ability to divide, there was no indication of such a recovery in AT cells up to 120 h after bleomycin treatment. A similar level of breakage of DNA occurred in both cell types after incubation with bleomycin. The rate of repair of these breaks was also the same. DNA synthesis was found to be more resistant to bleomycin in AT cells than in control cells. The latter data are in keeping with results previously obtained using ionizing radiation. 相似文献
4.
M F Norman T N Lavin J D Baxter B L West 《The Journal of biological chemistry》1989,264(20):12063-12073
5.
The beta 1-adrenergic receptor of the turkey erythrocyte. Molecular heterogeneity revealed by purification and photoaffinity labeling 总被引:6,自引:0,他引:6
R G Shorr M W Strohsacker T N Lavin R J Lefkowitz M G Caron 《The Journal of biological chemistry》1982,257(20):12341-12350
The beta 1-adrenergic receptor of turkey erythrocytes has been purified by a combination of affinity and high performance steric exclusion chromatography. These procedures provide preparations with specific activities of greater than 15,000 pmol/mg of protein with an overall recovery of approximately 30% of the receptor activity solubilized from membrane preparations. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of radioiodinated purified receptor reveals two bands of labeled protein with apparent Mr = 40,000 +/- 2,000 and 45,000 +/- 3,000 in a 3-4:1 ratio. These same two peptides can also be labeled specifically and in approximately the same ration in both membranes and purified preparations using the photoaffinity probe 125I-labeled p-azidobenzylcarazolol. When the two purified polypeptides are completely separated by high performance liquid chromatography and subjected to detailed ligand binding studies, identical beta 1-adrenergic specificities are found for the two receptor forms. Preliminary characterization of these two proteins by partial protease digestion suggests a large degree of similarity between them, albeit with some significant differences. These results demonstrate that both purification and photoaffinity labeling identify two polypeptides in turkey erythrocyte membranes as containing a beta 1-adrenergic receptor binding site. The functional and structural relationships of these two forms of the receptor remain to be elucidated. 相似文献
6.
M F Lavin P McCombie C Kidson 《International journal of radiation biology and related studies in physics, chemistry, and medicine》1976,30(1):31-40
Mouse neuroblastoma cells differentiate when grown in the absence of serum; differentiation is reversed on the addition of serum. Differentiated cells are more sensitive to U.V.-radiation than proliferating cells. Whereas addition of serum to differentiated neuroblastoma cells normally results in immediate, synchronous entry into S phase, irradiation just before the addition of serum results in a long delay in the onset of DNA replication. During this lag period, incorporated 3H-thymidine appears in the light density region of CsCl gradientss, reflecting either repair synthesis or abortive replication. Post-replication repair (gap-filling) was found to be present in proliferating cells and at certain times in differentiated cells. It is suggested that the sensitivity of differentiated neuroblastoma cells to U.V.-radiation may be due to ineffective post-replication repair or to deficiencies in more than one repair mechanism, with reduction in repair capacity beyond a critical threshold. 相似文献
7.
Jason J. Kolbe Brian R. Lavin Russell L. Burke Lorenzo Rugiero Massimo Capula Luca Luiselli 《Biological invasions》2013,15(4):775-783
Tests of invasion success often require comparisons between introduced and native populations, but determining the native-range sources for introduced populations can be difficult. Molecular markers can help clarify the geographic extent of native-range sources, helping to identify which populations are appropriate for comparative studies. The Italian Wall Lizard (Podarcis siculus) was introduced multiple times to the United States with extant populations in California, Kansas, New Jersey, and New York. We used phylogeographic analysis of mtDNA sequences (cytb gene) for individuals sampled from these introduced populations and across the native range to identify the number of independent introductions and the location of the source populations. Haplotypes sampled from introduced populations were nested within three geographically distinct, well-supported clades that together encompassed a large portion of the native range. Combining these phylogeographic results with documentation of the introductions revealed putative sources: California individuals are derived from Sicily; Kansas and New York populations are from Tuscany near Florence; and the New Jersey population is likely from the Adriatic coastal region, but a more specific locality is not possible. The pet trade dominates the invasion pathway for P. siculus introductions to the US. The genetically and geographically diverse sampling of its native range may be driven by the desire for phenotypic variety in the pet trade, a hypothesis that needs future testing. 相似文献
8.
9.
Tyler J. Brummer Kimberley T. Taylor Jay Rotella Bruce D. Maxwell Lisa J. Rew Matt Lavin 《Ecosystems》2016,19(6):986-1000
Bromus tectorum can transform ecosystems causing negative impacts on the ecological and economic values of sagebrush steppe of the western USA. Although our knowledge of the drivers of the regional distribution of B. tectorum has improved, we have yet to determine the relative importance of climate and local factors causing B. tectorum abundance and impact. To address this, we sampled 555 sites distributed geographically and ecologically throughout the sagebrush steppe. We recorded the canopy cover of B. tectorum, as well as local substrate and vegetation characteristics. Boosted regression tree modeling revealed that climate strongly limits the transformative ability of B. tectorum to a portion of the sagebrush steppe with dry summers (that is, July precipitation <10 mm and the driest annual quarter associated with a mean temperature >15°C) and low native grass canopy cover. This portion includes the Bonneville, Columbia, Lahontan, and lower Snake River basins. These areas are likely to require extreme efforts to reverse B. tectorum transformation. Our predictions, using future climate conditions, suggest that the transformative ability of B. tectorum may not expand geographically and could remain within the same climatically suitable basins. We found B. tectorum in locally disturbed areas within or adjacent to all of our sample sites, but not necessarily within sagebrush steppe vegetation. Conversion of the sagebrush steppe by B. tectorum, therefore, is more likely to occur outside the confines of its current climatically optimal region because of site-specific disturbances, including invasive species control efforts and sagebrush steppe mismanagement, rather than climate change. 相似文献
10.
Irisin was first identified in muscle cells. We detected irisin immunoreactivity in various organs of the crested porcupine (Hystrix cristata). In the epidermis, irisin immunoreactivity was localized mainly in stratum basale, stratum spinosum and stratum granulosum layers; immunoreactivity was not observed in the stratum corneum. In the dermis, irisin was found in the external and internal root sheath, cortex and medulla of hair follicles, and in sebaceous glands. Irisin immunoreactivity was found in the neural retina and skeletal muscle fibers associated with the eye. The pineal and thyroid glands also exhibited irisin immunoreactivity. 相似文献