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991.
The fluid mosaic model of membrane structure has been revised in recent years as it has become evident that domains of different lipid composition are present in eukaryotic and prokaryotic cells. Using membrane binding fluorescent dyes, we demonstrate the presence of lipid spirals extending along the long axis of cells of the rod-shaped bacterium Bacillus subtilis. These spiral structures are absent from cells in which the synthesis of phosphatidylglycerol is disrupted, suggesting an enrichment in anionic phospholipids. Green fluorescent protein fusions of the cell division protein MinD also form spiral structures and these were shown by fluorescence resonance energy transfer to be coincident with the lipid spirals. These data indicate a higher level of membrane lipid organization than previously observed and a primary role for lipid spirals in determining the site of cell division in bacterial cells. 相似文献
992.
Moso bamboo (Phyllostachys pubescens) is widely distributed in the acid soil region of Southern China, where great potential of aluminum (Al) toxicity exists.
To evaluate the Al tolerance of Moso bamboo, seed germination and root elongation were compared with two rice cultivars, and
physical and physiological damages were examined under various levels of Al stress. Results showed that Moso bamboo seed germination
was inhibited when Al concentration increased to 500 μM, and the median lethal concentration was 2,000 μM. Comparatively,
the rice seed germination was not inhibited even at a concentration of 2,000 μM Al. Aluminum accumulated mainly in the cell
wall of root apices, and entered into protoplasts as treating time prolonged and/or Al concentration increased, which resulted
in apoptosis. The bamboo root epidermis degraded significantly in the presence of 2,000 μM Al. In conclusion, Moso bamboo
is moderately weak in Al tolerance. 相似文献
993.
Sarah C. Webb Anthony Attwood Tony Brooks Tom Freeman Phil Gardner Clare Pritchard Debbie Williams Peter Underhill Mark A. Strivens Andy Greenfield Ekaterina Pilicheva 《Mammalian genome》2004,15(9):740-747
Microarrays allow monitoring of gene expression for tens of thousands of genes in parallel and are being used routinely to generate huge amounts of valuable data. Handling and analysis of such data are becoming major bottlenecks in the utilization of the technology. To enable the researcher to interpret the results postanalysis, we have developed a laboratory information management system for microarrays (LIMaS) with an n-tier Java front-end and relational database to record and manage large-scale expression data preanalysis. This system enables the laboratory to replace the paper trail with an efficient and fully customizable interface giving it the ability to adapt to any working practice, e.g., handling many resources used to form many products (chaining of resources). The ability to define sets of activities, resources, and workflows makes LIMaS MIAME-supportive.LIMaS is available for download at (http://www.mgu.har.mrc.ac.uk/microarray.) 相似文献
994.
Kristina M. Fetalvero Yenyen Yu Margaret Goetschkes Guiqing Liang Reginald A. Valdez Ty Gould Ellen Triantafellow Sebastian Bergling Joseph Loureiro John Eash Victor Lin Jeffrey A. Porter Peter M. Finan Kenneth Walsh Yi Yang Xiaohong Mao Leon O. Murphy 《Molecular and cellular biology》2013,33(1):98-110
Autophagy is a vesicular trafficking pathway that regulates the degradation of aggregated proteins and damaged organelles. Initiation of autophagy requires several multiprotein signaling complexes, such as the ULK1 kinase complex and the Vps34 lipid kinase complex, which generates phosphatidylinositol 3-phosphate [PtdIns(3)P] on the forming autophagosomal membrane. Alterations in autophagy have been reported for various diseases, including myopathies. Here we show that skeletal muscle autophagy is compromised in mice deficient in the X-linked myotubular myopathy (XLMTM)-associated PtdIns(3)P phosphatase myotubularin (MTM1). Mtm1-deficient muscle displays several cellular abnormalities, including a profound increase in ubiquitin aggregates and abnormal mitochondria. Further, we show that Mtm1 deficiency is accompanied by activation of mTORC1 signaling, which persists even following starvation. In vivo pharmacological inhibition of mTOR is sufficient to normalize aberrant autophagy and improve muscle phenotypes in Mtm1 null mice. These results suggest that aberrant mTORC1 signaling and impaired autophagy are consequences of the loss of Mtm1 and may play a primary role in disease pathogenesis. 相似文献
995.
Jin-yi Wu Almutamad Sheikho He Ma Tian-ci Li Ya-qi Zhao Ya-lin Zhang Dun Wang 《Cytotechnology》2017,69(6):875-883
Bombyx batryticatus is a traditional Chinese medicine. To understand apoptotic effect of B. batryticatus ethanol extract (BBE), we investigated the role of BBE in inducing apoptosis of human gastric cancer cells SGC-7901. Cells treated with BBE and apoptosis was assessed by methyl thiazolyl tetrazolium (MTT) assay, morphological changes, DNA fragmentation and flow cytometry assays. The expression of Bcl-2, Bax and P21 were evaluated by western blot analysis and real time polymerase chain reaction. MTT assay showed that the cytotoxicity of BBE extract on SGC-7901 cells was correlated with treatment time and concentration. After treatment with 6 mg/mL of BBE the microscopy showed that, the majority of SGC-7901 cells were obviously reduced, distorted and grew slowly. Annexin-V/propidium iodide double-staining assay emerge the early apoptosis and the late apoptosis after treatment with different times by laser confocal fluorescence microscopy and flow cytometer. Cell cycle analysis of SGC 79 cells showed that BBE induced cell cycle arrest in the G1 and G2 phases. DNA fragmentation indicated the trend of BBE inducing apoptosis on SGC-7901 cells. The qRT-PCR and western blot analysis indicated that the mRNA and protein expressions of Bax and P21 were significantly up-regulated whereas that of Bc1-2 was down-regulated after treatment with BBE for 24 h. Our results revealed a correlation between gene regulation and BBE-induced apoptosis, which might indicate the potential of BBE in cancer therapy. 相似文献
996.
Chen-Guang Zhang Xiao Liu Yi-Lei Fan Mao Wang Yong-Fu Chai Peng-Cheng Wan Ya-Min Wang Ming Yue 《Acta Physiologiae Plantarum》2016,38(4):100
The physiological effects of sunflecks on understory plants are poorly understood. Kingdonia uniflora is an endemic and endangered species in China, with a patchy distribution over much of its range. Sunflecks are reportedly the likely dominant factor in determining its patchy distribution. We studied the photosynthesis of K. uniflora in the field to test whether understory sunflecks result in photoinhibition and, thereby, potentially influence its patchy distribution. K. uniflora exhibited the low dark respiration rates, low light compensation points, and low light saturation points characteristic of shade-tolerant plants, allowing maintenance during the long periods of low understory light. Moreover, K. uniflora was able to regulate light energy utilization by non-photochemical quenching in low light. Gas exchange parameters were measured in six treatments (sunfleck-enriched, sunfleck-enriched with added saturation light, sunfleck-enriched with filtered ultraviolet-B (UV-B) radiation , sunfleck-limited, sunfleck-limited with added saturation light, and sunfleck-limited with filtered UV-B). The sunfleck-enriched treatment caused photoinhibition in K. uniflora, in part due to a UV-B-induced decrease in Pn. In addition, the application of simulated sunflecks indicated that K. uniflora leaves do not need continuous light. The photosynthetic responses of K. uniflora to sunflecks indicate that the sunflecks are a limiting factor in the small-scale distribution of K. uniflora. 相似文献
997.
IMMUNOGLOBULIN polypeptide chains consist of two well defined regions designated the “variable region” and the “constant region”. Whereas great diversity exists in amino-acid sequences of variable regions, the constant regions of a given subclass of heavy chains (CH)* are essentially invariant in sequence1, 2. Exceptions are the allelic forms, such as the rabbit allotypes A14 and A153, 4, where a threonine-alanine interchange occurs in the constant region of γ chains (Appella, Chersi, R. G. M. and Dubiski, in preparation). The markers unique to a chains (for example, A14-A15) are closely linked to allotypic markers at the a locus (a1, a2, a3)3, 4 which seem to be present on four different Ig heavy chain classes (α, γ, ε, µ)5–7. These puzzling observations can be explained if the a locus determinants are variable region markers which reflect genetically controlled differences in some relatively constant residues within the VH region sequences7. 相似文献
998.
Insulin like growth factor-1 (IGF-1) plays an important role in the proliferation and differentiation of neural progenitor
cells. The effects of IGF-1 can be regulated by insulin like growth factor binding protein-3 (IGFBP-3) which can either inhibit
or stimulate the proliferation of cells depending on the expression of proteases that can release IGF-1 from IGF1-IGFBP3 complex.
Although IGF-1 is essential for the development of brain, both IGFBP-3 and IGF-1 are elevated in the brains of children younger
than 6 months of age. Likewise, IGFBP-3 is also upregulated following cerebral ischemia and hypoxia. However, the role of
IGFBP-3 in neurogenesis is not clear. Using an in vitro culture system of rat neural progenitor cells, we demonstrate that
IGFBP-3 specifically regulates the IGF-1 mediated neural progenitor cell proliferation via down regulation of phopho-Akt,
and cyclin D1. In addition, IGFBP-3 also decreased the content of nestin in the neural progenitor cells indicating its potential
role in neurogenesis. 相似文献
999.
Nigel W. Kerby Gordon W. Niven Peter Rowell William D. P. Stewart 《Applied microbiology and biotechnology》1987,25(6):547-552
Summary Mutant strains of the N2-fixing cyanobacterium bacterium Anabaena variabilis resistant to 6-fluorotryptophan or to ethionine were isolated. Many of these strains liberated amino acids into their media in the absence of 6-fluorotryptophan and ethionine. Nitrogenase activity was higher in mutant strains than in the parent strain. Mutant strains were immobilised in calcium alginate and sustained photoproduction of amino acids has been demonstrated.Abbreviations ETH
ethionine
- FT
6-fluorotryptophan
- Hepes
4-(2-hydroxyethyl)-1, piperazine ethanesulphonic acid
- PEP
phosphoenolpyruvate
- DAHP
3-deoxy-d-arabinoheptulosonate 7-phosphate
- chl a
chlorophyll a 相似文献
1000.