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排序方式: 共有1233条查询结果,搜索用时 15 毫秒
91.
92.
Ohta N Aizu M Kaneko T Sato T Kobayashi H 《Journal of experimental zoology. Part A, Comparative experimental biology》2003,295(2):117-126
Lysenin is a 33-kDa protein found in the coelomic fluid (CF) of the earthworm Eisenia foetida. Purified lysenin binds specifically to sphingomyelin (SM). In the present studies, we found that the white cloud mountain minnow Tanichthys albonubes and the Mozambique tilapia Oreochromis mossambicus died in solutions of lysenin (at concentrations above 2.5 microg/ml) and CF (0.6%, v/v) within 2 h. The gills of both species of fish were damaged similarly by lysenin and by CF. Most gill lamellae became irregularly bent or curled, with swelling of the epithelial cells of the lamellae. Red blood cells in the lamellar vascular sinuses, in the central venous sinuses, and in the blood vessels of the entire body became swollen and lysed, choking the sinuses. Epithelial cells in the skin were also damaged. When fish of both species were treated with lysenin or CF that had been incubated with SM-liposomes, they did not die. Their behavior remained normal and there was no damage to any cells or tissues. These findings suggest that SM might be involved in the lethal effects of lysenin and CF. It is likely that purified lysenin and lysenin in CF bound to SM in the cell membranes of the tissues mentioned above, damaging the cells. The presence of SM in the gills and skin was confirmed, supporting this hypothesis. The damage to gills and hemolysis might have resulted in lethal respiratory problems. Damage to the skin might disturb the exchange of ions through the skin, hastening death. Damage by lysenin and CF to epithelial cells of the cornea and the wall of the oral cavity was also recognized, but there was no such damage to the intestine. 相似文献
93.
Aberrant chloroplasts in transgenic rice plants expressing a high level of maize NADP-dependent malic enzyme 总被引:16,自引:0,他引:16
NADP-dependent malic enzyme (NADP-ME) is a major decarboxylating enzyme in NADP-ME-type C4 species such as maize and Flaveria. In this study, chloroplastic NADP-ME was transferred to rice (Oryza sativa L.) using a chimeric gene composed of maize NADP-ME cDNA under the control of rice light-harvesting chlorophyll-a/b-binding protein (Cab) promoter. There was a 20- to 70-fold increase in the NADP-ME activity in leaves of transgenic rice
compared to that in wild-type rice plants. Immunocytochemical studies by electron microscopy showed that maize NADP-ME was
mostly localized in chloroplasts in transgenic rice plants, and that the chloroplasts were agranal without thylakoid stacking.
Chlorophyll content and photosystem II activity were inversely correlated with the level of NADP-ME activity. These results
suggest that aberrant chloroplasts in transgenic plants may be caused by excessive NADP-ME activity. Based on these results
and the known fact that only bundle sheath cells of NADP-ME species, among all three C4 subgroups, have agranal chloroplasts, we postulate that a high level of chloroplastic NADP-ME activity could strongly affect
the development of chloroplasts.
Received: 27 January 1999 / Accepted: 20 January 2000 相似文献
94.
cDNA cloning, gene expression and subcellular localization of anthocyanin 5-aromatic acyltransferase from
Gentiana triflora 总被引:5,自引:3,他引:2
Hiroyuki Fujiwara Yoshikazu Tanaka Keiko Yonekura-Sakakibara Masako Fukuchi-Mizutani Masahiro Nakao Yuko Fukui Masaatsu Yamaguchi Toshihiko Ashikari Takaaki Kusumi 《The Plant journal : for cell and molecular biology》1998,16(4):421-431
Acylation of anthocyanins with hydroxycinnamic acid derivatives is one of the most important and less understood modification reactions during anthocyanin biosynthesis. Anthocyanin aromatic acyltransferase catalyses the transfer of hydroxycinnamic acid moieties from their CoA esters to the glycosyl groups of anthocyanins. A full-length cDNA encoding the anthocyanin 5-aromatic acyltransferase (5AT) ( EC 2.3.1.153 ) that acylates the glucose bound at the 5-position of anthocyanidin 3,5-diglucoside was isolated from petals of Gentiana triflora on the basis of the amino acid sequence of the purified enzyme. The isolated full-length cDNA had an open reading frame of 469 amino acids and the calculated molecular weight was 52 736. The deduced amino acid sequence contains consensus motifs that are conserved among the putative acyl CoA-mediated acyltransferases, and this indicates that 5AT is a member of a proposed superfamily of multifunctional acyltransferases ( St-Pierre et al . (1998 ) Plant J. 14, 703–713). The cDNA was expressed in Escherichia coli and yeast, and confirmed to encode 5AT. The enzymatic characteristics of the recombinant 5AT were consistent with those of the native gentian 5AT. Immunoblot analysis using specific antibodies to 5AT showed that the 5AT protein is present in petals, but not in sepals, stems or leaves of G. triflora . RNA blot analysis showed that the 5AT gene is expressed only in petals and that its expression is temporally regulated during flower development coordinately with other anthocyanin biosynthetic genes. Immunohistochemical analysis demonstrated that the 5AT protein is specifically expressed in the outer epidermal cells of gentian petals and that it is localized mainly in the cytosol. 相似文献
95.
Yumi Moriwake Yoshiyuki Tohno Setsuko Tohno Takeshi Minami Masako Utsumi Fumio Nishiwaki Masa-oki Yamada Hiroshi Yamamoto Yuko Okazaki Tadashi Fujii Yoshinori Takakura 《Biological trace element research》1998,64(1-3):229-235
The relative contents (RCs) of elements in the human menisci from 23 subjects in the age range between 65 and 93 yr were analyzed
by inductively coupled plasma atomic emission spectrometry. The RCs of sulfur, calcium, and phosphorus in menisci increased
progressively until the 80s, being the highest in the 80s, and thereafter decreased. The RCs of magnesium in menisci increased
progressively until the 90s. Regarding the medial and lateral menisci, higher RCs of magnesium and iron, and a lower RC of
phosphorus were found in lateral menisci in comparison with those in medial menisci.
There were sexual differences in the RCs of calcium and phosphorus of medial and lateral menisci. The RCs of calcium and phosphorus
were about 50% higher in women’s menisci than in men’s. Histological examinations showed that structureless mucoid masses
were observed in the menisci, with very high RCs of calcium and phosphorus being detected. 相似文献
96.
Masako Takashima Ri-ichiroh Manabe Wataru Iwasaki Akira Ohyama Moriya Ohkuma Takashi Sugita 《PloS one》2015,10(8)
The order Trichosporonales (Tremellomycotina, Basidiomycota) includes various species that have clinical, agricultural and biotechnological value. Thus, understanding why and how evolutionary diversification occurred within this order is extremely important. This study clarified the phylogenetic relationships among Tricosporonales species. To select genes suitable for phylogenetic analysis, we determined the draft genomes of 17 Trichosporonales species and extracted 30 protein-coding DNA sequences (CDSs) from genomic data. The CDS regions of Trichosporon asahii and T. faecale were identified by referring to mRNA sequence data since the intron positions of the respective genes differed from those of Cryptococcus neoformans (outgroup) and are not conserved within this order. A multiple alignment of the respective gene was first constructed using the CDSs of T. asahii, T. faecale and C. neoformans, and those of other species were added and aligned based on codons. The phylogenetic trees were constructed based on each gene and a concatenated alignment. Resolution of the maximum-likelihood trees estimated from the concatenated dataset based on both nucleotide (72,531) and amino acid (24,173) sequences were greater than in previous reports. In addition, we found that several genes, such as phosphatidylinositol 3-kinase TOR1 and glutamate synthase (NADH), had good resolution in this group (even when used alone). Our study proposes a set of genes suitable for constructing a phylogenetic tree with high resolution to examine evolutionary diversification in Trichosporonales. These can also be used for epidemiological and biogeographical studies, and may also serve as the basis for a comprehensive reclassification of pleomorphic fungi. 相似文献
97.
Kristina Kirschner Shamith A. Samarajiwa Jonathan M. Cairns Suraj Menon Pedro A. Pérez-Mancera Kosuke Tomimatsu Camino Bermejo-Rodriguez Yoko Ito Tamir Chandra Masako Narita Scott K. Lyons Andy G. Lynch Hiroshi Kimura Tetsuya Ohbayashi Simon Tavaré Masashi Narita 《PLoS genetics》2015,11(3)
The downstream functions of the DNA binding tumor suppressor p53 vary depending on the cellular context, and persistent p53 activation has recently been implicated in tumor suppression and senescence. However, genome-wide information about p53-target gene regulation has been derived mostly from acute genotoxic conditions. Using ChIP-seq and expression data, we have found distinct p53 binding profiles between acutely activated (through DNA damage) and chronically activated (in senescent or pro-apoptotic conditions) p53. Compared to the classical ‘acute’ p53 binding profile, ‘chronic’ p53 peaks were closely associated with CpG-islands. Furthermore, the chronic CpG-island binding of p53 conferred distinct expression patterns between senescent and pro-apoptotic conditions. Using the p53 targets seen in the chronic conditions together with external high-throughput datasets, we have built p53 networks that revealed extensive self-regulatory ‘p53 hubs’ where p53 and many p53 targets can physically interact with each other. Integrating these results with public clinical datasets identified the cancer-associated lipogenic enzyme, SCD, which we found to be directly repressed by p53 through the CpG-island promoter, providing a mechanistic link between p53 and the ‘lipogenic phenotype’, a hallmark of cancer. Our data reveal distinct phenotype associations of chronic p53 targets that underlie specific gene regulatory mechanisms. 相似文献
98.
99.
Elham Fakhrejahani Masae Torii Toshiyuki Kitai Shotaro Kanao Yasufumi Asao Yohei Hashizume Yoshiki Mikami Iku Yamaga Masako Kataoka Tomoharu Sugie Masahiro Takada Hironori Haga Kaori Togashi Tsuyoshi Shiina Masakazu Toi 《PloS one》2015,10(10)
Photoacoustic tomography is a recently developed imaging modality that can provide high spatial-resolution images of hemoglobin distribution in tissues such as the breast. Because breast cancer is an angiogenesis-dependent type of malignancy, we evaluated the clinical acceptability of breast tissue images produced using our first prototype photoacoustic mammography (PAM) system in patients with known cancer. Post-excisionally, histological sections of the tumors were stained immunohistochemically (IHC) for CD31 (an endothelial marker) and carbonic anhydrase IX (CAIX) (a marker of hypoxia). Whole-slide scanning and image analyses were used to evaluate the tumor microvessel distribution pattern and to calculate the total vascular perimeter (TVP)/area for each lesion. In this clinical study, 42 lesions were primarily scanned using PAM preoperatively, three of which were reported to be benign and were excluded from statistical analysis. Images were produced for 29 out of 39 cancers (visibility rate = 74.4%) at the median depth of 26.5 (3.25–51.2) mm. Age, menopausal status, body mass index, history of neoadjuvant treatment, clinical stage and histological tumor angiogenesis markers did not seem to affect the visibility. The oxygen saturation level in all of the measured lesions was lower than in the subcutaneous counterpart vessels (Wilcoxon test, p value<0.001), as well as in the counterpart contralateral normal breast region of interest (ROI) (Wilcoxon test, p value = 0.001). Although the oxygen saturation level was not statistically significant between CAIX-positive vs. -negative cases, lesional TVP/area showed a positive correlation with the oxygen saturation level only in the group that had received therapy before PAM. In conclusion, the vascular and oxygenation data obtained by PAM have great potential for identifying functional features of breast tumors. 相似文献
100.
Toshio Fumoto Kiyo-aki Ishii Masako Ito Stefan Berger Günther Schütz Kyoji Ikeda 《Biochemical and biophysical research communications》2014
Although the mineralocorticoid receptor (MR) is expressed in osteoblasts and osteocytes and frequently co-localizes with the glucocorticoid receptors (GR), its pathophysiological functions in bone remain elusive. We report here that pharmacologic inhibition of MR function with eplerenone resulted in increased bone mass, with stimulation of bone formation and suppression of resorption, while specific genetic deletion of MR in osteoblast lineage cells had no effect. Further, treatment with eplerenone as well as specific deletion of MR in osteocytes ameliorated the cortical bone thinning caused by slow-release prednisolone pellets. Thus, MR may be involved in the deleterious effects of glucocorticoid excess on cortical bone. 相似文献