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排序方式: 共有117条查询结果,搜索用时 15 毫秒
81.
Cellular Response of Pea Plants to Cadmium Toxicity: Cross Talk between Reactive Oxygen Species, Nitric Oxide, and Calcium 总被引:8,自引:0,他引:8
82.
Cellular and subcellular localization of endogenous nitric oxide in young and senescent pea plants 总被引:32,自引:0,他引:32
Corpas FJ Barroso JB Carreras A Quirós M León AM Romero-Puertas MC Esteban FJ Valderrama R Palma JM Sandalio LM Gómez M del Río LA 《Plant physiology》2004,136(1):2722-2733
The cellular and subcellular localization of endogenous nitric oxide (NO.) in leaves from young and senescent pea (Pisum sativum) plants was studied. Confocal laser scanning microscopy analysis of pea leaf sections with the fluorescent probe 4,5-diaminofluorescein diacetate revealed that endogenous NO. was mainly present in vascular tissues (xylem and phloem). Green fluorescence spots were also detected in the epidermal cells, palisade and spongy mesophyll cells, and guard cells. In senescent leaves, NO. generation was clearly reduced in the vascular tissues. At the subcellular level, by electron paramagnetic resonance spectroscopy with the spin trap Fe(MGD)(2) and fluorometric analysis with 4,5-diaminofluorescein diacetate, NO. was found to be an endogenous metabolite of peroxisomes. The characteristic three-line electron paramagnetic resonance spectrum of NO., with g = 2.05 and a(N) = 12.8 G, was detected in peroxisomes. By fluorometry, NO. was also found in these organelles, and the level measured of NO. was linearly dependent on the amount of peroxisomal protein. The enzymatic production of NO. from l-Arg (nitric oxide synthase [NOS]-like activity) was measured by ozone chemiluminiscence. The specific activity of peroxisomal NOS was 4.9 nmol NO. mg(-1) protein min(-1); was strictly dependent on NADPH, calmodulin, and BH(4); and required calcium. In senescent pea leaves, the NOS-like activity of peroxisomes was down-regulated by 72%. It is proposed that peroxisomal NO. could be involved in the process of senescence of pea leaves. 相似文献
83.
Localization of nitric-oxide synthase in plant peroxisomes 总被引:24,自引:0,他引:24
Barroso JB Corpas FJ Carreras A Sandalio LM Valderrama R Palma JM Lupiáñez JA del Río LA 《The Journal of biological chemistry》1999,274(51):36729-36733
The presence of nitric-oxide synthase (NOS) in peroxisomes from leaves of pea plants (Pisum sativum L.) was studied. Plant organelles were purified by differential and sucrose density gradient centrifugation. In purified intact peroxisomes a Ca(2+)-dependent NOS activity of 5.61 nmol of L-[(3)H]citrulline mg(-1) protein min(-1) was measured while no activity was detected in mitochondria. The peroxisomal NOS activity was clearly inhibited (60-90%) by different well characterized inhibitors of mammalian NO synthases. The immunoblot analysis of peroxisomes with a polyclonal antibody against the C terminus region of murine iNOS revealed an immunoreactive protein of 130 kDa. Electron microscopy immunogold-labeling confirmed the subcellular localization of NOS in the matrix of peroxisomes as well as in chloroplasts. The presence of NOS in peroxisomes suggests that these oxidative organelles are a cellular source of nitric oxide (NO) and implies new roles for peroxisomes in the cellular signal transduction mechanisms. 相似文献
84.
Eduardo L pez-Huertas Luisa M. Sandalio Manuel G mez Luis A. Del Rí d 《Free radical research》1997,26(6):497-506
Peroxisomes were isolated from pea (Pisum sativum L.) leaves and the peroxisomal membranes were purified by treatment with Na2CO3. The production of superoxide radicals (O2-) induced by NADH was investigated in peroxisomal membranes from intact organelles incubated with proteases (pronase E and proteinase K). Under isoosmotic conditions, in the presence of pronase E, the production of O2- radicals was inhibited by 80%. SDS-PAGE of peroxisomal membranes after protease treatment demonstrated a decrease in the 18-kDa PMP. This suggests that this polypeptide has a small fragment exposed to the cytosolic side of the peroxisomal membrane which is essential for O2-production. The 18-kDa PMP was purified by preparative SDS-PAGE and in the reconstituted protein the NADH-driven production of O2- radicals was investigated. The isolated polypeptide showed a high generation rate of superoxide (about 300 nmol O2- × mg-1 protein × min-1) which was completely inhibited by 50 mM pyridine. The 18-kDa PMP was recognized by a polyclonal antibody against Cyt b5 from human ery-throcytes. The presence of b-type cytochrome in peroxisomal membranes was demonstrated by difference spectroscopy. Results obtained show that in the NADH-dependent O2- radical generating system of peroxisomal membranes, the 18-kDa integral membrane polypeptide, which appears to be Cyt b5, is clearly involved in superoxide radical production. 相似文献
85.
Yonekawa H; Moriwaki K; Gotoh O; Miyashita N; Matsushima Y; Shi LM; Cho WS; Zhen XL; Tagashira Y 《Molecular biology and evolution》1988,5(1):63-78
The Japanese mouse, Mus musculus molossinus, has long been considered an
independent subspecies of the house mouse. A survey of restriction- site
haplotypes of mitochondrial DNA (mtDNA) showed that Japanese mice have two
main maternal lineages. The most common haplotype is closely related to the
mtDNA of the European subspecies M. m. musculus. The other common haplotype
and two minor ones are closely related to each other and to the mtDNA of an
Asiatic subspecies, M. m. castaneus. Two other rare variants are probably
the result of recent contamination by European M. m. domesticus. The
musculus type of mtDNA is found in the southern two-thirds of Japan,
whereas the common castaneus type is found in the northern third and the
minor variants are found sporadically throughout Japan. The castaneus mtDNA
lineage had a few minor variants, whereas the musculus lineage was
completely monomorphic. By contrast, the native population of M. m.
castaneus and the Chinese and Korean musculus populations were highly
polymorphic. These results suggest that M. m. molossinus is a hybrid
between ancestral colonies, possibly very small, of M. m. musculus and M.
m. castaneus, rather than an independent subspecies.
相似文献
86.
Isoenzymes of Superoxide Dismutase in Nodules of Phaseolus vulgaris L., Pisum sativum L., and Vigna unguiculata (L.) Walp 下载免费PDF全文
The activity and isozymic composition of superoxide dismutase (SOD; EC 1.15.1.1) were determined in nodules of Phaseolus vulgaris L., Pisum sativum L., and Vigna unguiculata (L.) Walp. formed by Rhizobium phaseoll 3622, R. Ieguminosarum 3855, and Bradyrhizobium sp. BR7301, respectively. A Mn-SOD was present in Rhizobium and two in Bradyrhizobium and bacteroids. Nodule mitochondria from all three legume species had a single Mn-SOD with similar relative mobility, whereas the cytosol contained several CuZn-SODs: two in Phaseolus and Pisum, and four in Vigna. In the cytoplasm of V. unguiculata nodules, a Fe-containing SOD was also present, with an electrophoretic mobility between those of CuZn- and Mn-SODs, and an estimated molecular weight of 57,000. Total SOD activity of the soluble fraction of host cells, expressed on a nodule fresh weight basis, exceeded markedly that of bacteroids. Likewise, specific SOD activities of free-living bacteria were superior or equal to those of their symbiotic forms. Soluble extracts of bacteria and bacteroids did not show peroxidase activity (EC 1.11.1.7), but the nodule cell cytoplasm contained diverse peroxidase isozymes which were readily distinguishable from leghemoglobin components by electrophoresis. Data indicated that peroxidases and leghemoglobins did not significantly interfere with SOD localization on gels. Treatment with chloroform-ethanol scarcely affected the isozymic pattern of SODs and peroxidases, and had limited success in the removal of leghemoglobin. 相似文献
87.
88.
Interferon effects on microfilament organization cellular fibronectin distribution, and cell motility in human fibroblasts 总被引:23,自引:3,他引:20 下载免费PDF全文
We have shown previously (Pfeffer et al., 1979, Exp. Cell Res. 121:111-120) that treatment of human fibroblasts, planted at a density of 2x10(3) cells/cm(2), with purified human fibroblasts interferon (640 U/ml) for 3 d at 37 degrees C decreases the overall rate of cell proliferation to 35-40 percent of the control value. In the present experiments we have characterized the phenotype of interferon-inhibited fibroblasts. The mean volume of trypsinized, interferon-treated cells was increased 31 percent abover that of control cells. The interferon-treated population was much more heterogeneous than the control population with respect to volume, and there was a considerable overlap in the volume distributions of the two populations. The cell surface area was, on the average, increased 65 percent after interferon treatment. More than 80 percent of the treated cells had enlarged nuclei, many of which were lobed, and the fraction of binucleated cells was increased fivefold. After interferon treatment, over 40 percent of the cells showed large actin-containing fibers in the form of multiple parallel arrays. Fewer than 5 percent of the control cells contained such large actin fibers. The number of actin fibers of all sizes was tripled in the treated fibroblasts on a per cell basis and, calculated per unit surface area of the cells, the number was increased 82 percent. In contrast, 10-nm filaments and microtubules did not appear to be increased in number per unit surface area of the cells. The increases per cell in the abundance of these structures were directly related to increased cell size. After interferon treatment, fibronection was distributed in arrays of long filaments covering most portions of the cell surface. Interferon treatment markedly decreased the rate of cell locomotion as well as membrane ruffling and saltatory movements of intracellular granules. 相似文献
89.
Subcellular distribution of superoxide dismutase in leaves of ureide-producing leguminous plants 总被引:2,自引:0,他引:2
Francisco J. Corpas Luisa M. Sandalio José M. Palma Eduardo O. Leidi José A. Hernández Francisca Sevilla Luis A. del Río 《Physiologia plantarum》1991,82(2):285-291
The subcellular localization of superoxide dismutase (SOD; EC. 1.15.1.1) was studied in leaves of two ureide-producing leguminous plants ( Phaseolus vulgaris L. cv. Contender and Vigna unguiculata [L.] Walp). In leaves of Vigna and Phaseolus , three superoxide dismutases were found, an Mn-SOD and two Cu, Zn-containing SODs (I and II). Chloroplasts, mitochondria, and peroxisomes were purified by differential and density-gradient centrifugation using either Percoll or sucrose gradients. The yields obtained in intact chloroplasts and peroxisomes from Vigna were considerably higher than those achieved for Phaseolus . Purified chloroplasts only contained the Cu, Zn-SOD II isozyme, but in mitochondria both Mn-SOD and Cu, Zn-SOD I isozymes were present. In purified peroxisomes no SOD activity was detected. The absence of SOD activity in leaf peroxisomes from Vigna contrasts with results reported for the amide-metabolizing legume Pisum sativum L. where the occurrence of Mn-SOD was demonstrated in leaf peroxisomes (del Río et al. 1983. Planta 158: 216–224; Sandalio et al. 1987. Plant Sci. 51: 1–8). This suggests that in leaf peroxisomes from Vigna plants the generation of O2 - radicals under normal conditions probably does not take place. 相似文献
90.
Rodríguez-Serrano M Romero-Puertas MC Pastori GM Corpas FJ Sandalio LM del Río LA Palma JM 《Journal of experimental botany》2007,58(10):2417-2427
In this work the manganese superoxide dismutase (Mn-SOD) bound to peroxisomal membranes of watermelon cotyledons (Citrullus lanatus Schrad.) was purified to homogeneity and some of its molecular properties were determined. The stepwise purification procedure consisted of ammonium sulphate fractionation, batch anion-exchange chromatography, and anion-exchange and gel-filtration column chromatography using a fast protein liquid chromatography system. Peroxisomal membrane Mn-SOD (perMn-SOD; EC 1.15.1.1) was purified 5600-fold with a yield of 2.6 mug of enzyme g(-1) of cotyledons, and had a specific activity of 480 U mg(-1) of protein. The native molecular mass determined for perMn-SOD was 108 000 Da, and it was composed of four equal subunits of 27 kDa, which indicates that perMn-SOD is a homotetramer. Ultraviolet and visible absorption spectra of the enzyme showed a shoulder at 275 nm and two absorption maxima at 448 nm and 555 nm, respectively. By isoelectric focusing, a pI of 5.75 was determined for perMn-SOD. In immunoblot assays, purified perMn-SOD was recognized by a polyclonal antibody against Mn-SOD from pea leaves, and the peroxisomal enzyme rapidly dissociated in the presence of dithiothreitol and SDS. The potential binding of the Mn-SOD isozyme to the peroxisomal membrane was confirmed by immunoelectron microscopy analysis. The properties of perMn-SOD and the mitMn-SOD are compared and the possible function in peroxisomal membranes of the peripheral protein Mn-SOD is discussed. 相似文献