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排序方式: 共有221条查询结果,搜索用时 31 毫秒
91.
Kurita M Suzuki H Masai H Mizumoto K Ogata E Nishimoto I Aiso S Matsuoka M 《Biochemical and biophysical research communications》2004,324(2):554-561
Cdc7 expression repressor (CR)/periphilin has been originally cloned as an interactor with periplakin, a precursor of the cornified cell envelope, and suggested to constitute a new type of nuclear matrix. We here show that CR/periphilin is a ubiquitously expressed nuclear protein with speckled distribution. Overexpression of CR/periphilin induces S-phase arrest. Analysis of expression of regulators involved in DNA replication has revealed that both mRNA and protein expression of Cdc7, a regulator of the initiation and continuation of DNA replication, are markedly downregulated by overexpression of CR/periphilin. However, co-expression of Cdc7 only marginally rescues S-phase arrest induced by CR, indicating that CR retards S-phase progression by modifying expression of some genes including Cdc7, which are involved in progression of DNA replication or coordination of DNA replication and S-phase progression. 相似文献
92.
Tanaka Y Agha S Saudy N Kurbanov F Orito E Kato T Abo-Zeid M Khalaf M Miyakawa Y Mizokami M 《Journal of molecular evolution》2004,58(2):191-195
Hepatitis C virus (HCV) infects >10% of the general population in Egypt, in which intravenous injection with an antimony compound for endemic schistosomiasis in the past has been implicated. To simulate the epidemic history of HCV in Egypt, sera were obtained from 3608 blood donors at 13 governorates in or surrounding the Nile valley during 1999. The prevalence of antibody to HCV (anti-HCV) and genotypes was determined in them, and the molecular evolutionary analysis based on the neutral theory was applied to HCV isolates of genotype 4a, which is outstandingly prevalent in Egypt and indigenous there. Of 3608 sera, 317 (8.8%) were positive for anti-HCV. The molecular evolutionary analysis on 47 HCV genotype 4a isolates of carriers from various districts in Egypt indicated that the spread of HCV-4a would have increased exponentially during the 1940s through 1980 when oral medications became available. In conclusion, the estimated spread time is consistent with the duration of intravenous antimony campaigns in Egypt. 相似文献
93.
94.
Increased nicotianamine biosynthesis confers enhanced tolerance of high levels of metals, in particular nickel, to plants 总被引:7,自引:0,他引:7
Kim S Takahashi M Higuchi K Tsunoda K Nakanishi H Yoshimura E Mori S Nishizawa NK 《Plant & cell physiology》2005,46(11):1809-1818
Nicotianamine, a plant-derived chelator of metals, is produced by the trimerization of S-adenosylmethionine catalyzed by nicotianamine synthase. We established transgenic Arabidopsis and tobacco plants that constitutively overexpress the barley nicotianamine synthase gene. Nicotianamine synthase overexpression resulted in increased biosynthesis of nicotianamine in transgenic plants, which conferred enhanced tolerance of high levels of metals, particularly nickel, to plants. Promoter activities of four nicotianamine synthase genes in Arabidopsis were all increased in response to excess nickel, suggesting that nicotianamine plays an important role in the detoxification of nickel in plants. Furthermore, transgenic tobacco plants with a high level of nicotianamine grew well in a nickel-enriched serpentine soil without developing any symptoms of nickel toxicity. Our results indicate that nicotianamine plays a critical role in metal detoxification, and this can be a powerful tool for use in phytoremediation. 相似文献
95.
Masayuki?Kakimoto Atsushi?Kobayashi Ryouichi?Fukuda Yasuke?Ono Akinori?Ohta Etsuro?YoshimuraEmail author 《Biometals》2005,18(5):467-474
Genome-wide screening has identified 37 Al-tolerance genes in Saccharomyces cerevisiae. These genes can be roughly categorised into three groups on the basis of function, i.e., genes related to vesicle transport
processes, signal transduction pathways, and protein mannosylation. The largest group is composed of genes related to vesicle
transport processes; severe Al sensitivity was found in yeast strains lacking these genes. The retrograde transport of endosome-derived
vesicles back to the Golgi apparatus is an important factor in determining the Al tolerance of the vesicle transport system.
The PKC1-MAPK cascade signalling pathway is important in the Al tolerance of signal transduction. The lack of the gene implicated
in this process leads to weakened cell wall architecture, rendering the yeast Al-sensitive. Alternatively, Al might attack
the cell wall and/or plasma membrane, and, as signalling is prevented in cells devoid of the genes related to signalling processes,
the cells may be unable to alleviate the damage. The genes for protein mannosylation are also associated with Al tolerance,
demonstrating the importance of cell wall architecture. These genes are involved in cell integrity processes.
An erratum to this article is available at . 相似文献
96.
Shuichi Asano Satoru Ito Mika Morosawa Kishio Furuya Keiji Naruse Masahiro Sokabe Etsuro Yamaguchi Yoshinori Hasegawa 《Biochemistry and Biophysics Reports》2018
Activation of airway smooth muscle (ASM) cells plays a central role in the pathophysiology of asthma. Because ASM is an important therapeutic target in asthma, it is beneficial to develop bioengineered ASM models available for assessing physiological and biophysical properties of ASM cells. In the physiological condition in vivo, ASM cells are surrounded by extracellular matrix (ECM) and exposed to mechanical stresses such as cyclic stretch. We utilized a 3-D culture model of human ASM cells embedded in type-I collagen gel. We further examined the effects of cyclic mechanical stretch, which mimics tidal breathing, on cell orientation and expression of contractile proteins of ASM cells within the 3-D gel. ASM cells in type-I collagen exhibited a tissue-like structure with actin stress fiber formation and intracellular Ca2+ mobilization in response to methacholine. Uniaxial cyclic stretching enhanced alignment of nuclei and actin stress fibers of ASM cells. Moreover, expression of mRNAs for contractile proteins such as α-smooth muscle actin, calponin, myosin heavy chain 11, and transgelin of stretched ASM cells was significantly higher than that under the static condition. Our findings suggest that mechanical force and interaction with ECM affects development of the ASM tissue-like construct and differentiation to the contractile phenotype in a 3-D culture model. 相似文献
97.
The teleost dorsoventral axis cannot be distinguished morphologically before gastrulation. In order to examine whether the
yolk cell affects axis determination, we bisect early cleavage embryos of the goldfish, Carassius auratus. When the vegetal yolk hemisphere is removed by bisection along the equatorial plane at the 2-cell stage, the embryos develop
abnormally and exhibit a symmetrical morphology. No dorsal structures, such as notochord, somites and neural tube, differentiate
and no embryonic shield is formed during gastrulation. In addition, no goosecoid mRNA is expressed before gastrulation. The frequency of abnormality decreases as the age at which the vegetal yolk hemisphere
is removed increases. Most embryos removed at the 32-cell stage develop normally. Their morphological phenotype is similar
to that of a Xenopus ventralized embryo generated by ultraviolet irradiation on the vegetal hemisphere soon after fertilization. We also observed
that, when the embryos were bisected along the first cleavage plane at the 2-cell stage, the proportion of pairs of embryos
of which one embryo developed normally was 44.8%. These results indicate that the vegetal yolk hemisphere of the early cleavage
embryo of the goldfish contains axis determination factor(s), which are necessary for generation of dorsal structures. Furthermore,
it is suggested that these determinant(s) are distributed asymmetrically within the vegetal yolk hemisphere.
Received: 25 May 1996 / Accepted: 19 September 1996 相似文献
98.
99.
The phytosiderophores, mugineic acid (MA) and epi-hydroxymugineic acid (HMA), together with a related compound, nicotianamine
(NA), were investigated for their ability to bind Al(III). Potentiometric titration analysis demonstrated that MA and HMA
bind Al(III), in contrast to NA which does not under normal physiological conditions. With MA and HMA, in addition to the
Al complex (AlL), the protonated (AlLH) and deprotonated (AlLH−1) complexes were identified from an analysis of titration curves, where L denotes the phytosiderophore form in which all the
carboxylate functions are ionized. The equilibrium formation constants of the Al(III) phytosiderophore complexes are much
smaller than those of the corresponding Fe(III) complexes. The higher selectivity of phytosiderophores for Fe(III) over Al(III)
facilitates Fe(III) acquisition in alkaline conditions where free Al(III) levels are higher than free Fe(III) levels. 相似文献
100.
Kawakami Y Goto-Kazeto R Saito T Fujimoto T Higaki S Takahashi Y Arai K Yamaha E 《The International journal of developmental biology》2010,54(10):1493-1501
Primordial germ cells (PGCs) are the only cells in developing embryos with the potential to transmit genetic information to the next generation. In our previous study, a single PGC transplanted into a host differentiated into fertile gametes and produced germ-line chimeras of cyprinid fish, including zebrafish. In this study, we aimed to induce germ-line chimeras by transplanting donor PGCs from various sources (normal embryos at different stages, dissociated blastomeres, embryoids, or embryoids cryopreserved by vitrification) into host blastulae, and compare the migration rates of the PGCs towards the gonadal ridge. Isolated, cultured blastomeres not subject to mesodermal induction were able to differentiate into PGCs that retained their motility. Moreover, these PGCs successfully migrated towards the gonadal ridge of the host and formed viable gametes. Motility depended on developmental stage and culture duration: PGCs obtained at earlier developmental stages and with shorter cultivation periods showed an increased rate of migration to the gonadal ridge. Offspring were obtained from natural spawning between normal females and chimeric males. These results provide the basis for new methods of gene preservation in zebrafish. 相似文献