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排序方式: 共有443条查询结果,搜索用时 15 毫秒
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Escherichia coli CAN lacks a tRNA-processing nuclease.   总被引:3,自引:2,他引:1       下载免费PDF全文
Escherichia coli strain CAN is unable to support the growth of bacteriophage T4 strains requiring the suppressor function of T4 tRNASer. Biochemical analysis of the mutant strain revealed that it is deficient in a RNase which acts on the artificial tRNA precursor tRNA-C-U.  相似文献   
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Some interesting cultural observations on Scytonema stuposum (Kuetz.) Born., were recorded. It was observed that frequently one or more terminal cells of a branch get cut off but they still remain attached over the sheath of the mother filament. Even in this condition such structures continue their growth and may become a multicellular body. Later, such a structure gets detached from the mother filament and serve as a hormogonium.  相似文献   
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The present study was carried out to determine the detailed histological and cytological features of the excurrent ducts of the male reproductive system in the rhesus monkey. The excurrent ducts show a regional difference in their histological features. The use of some of these features as histological markers and their possible functional significance are discussed. The epithelial cells in the different components of the excurrent duct system possess cytological features which suggest their involvement in absorption and the secretion of different products into the lumen.  相似文献   
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This paper deals with stochasticm-compartmental systems with continuous time-dependent infusions into all compartments and reversible time-independent flows between any two compartments. A methodology for the first two moments of the distribution of the number of units in the different compartments at any point in time is outlined without resorting to the usual techniques of generating functions and inverse Laplace transforms. A possible application to a systems analysis of the kidney transplant system is discussed.  相似文献   
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Aziz M  Jacob A  Matsuda A  Wu R  Zhou M  Dong W  Yang WL  Wang P 《PloS one》2011,6(11):e27685
Milk fat globule-epidermal growth factor factor 8 (MFG-E8) regulates innate immune function by modulating cellular signaling, which is less understood. Herein, we aimed to investigate the direct anti-inflammatory role of MFG-E8 in macrophages by pre-treatment with recombinant murine MFG-E8 (rmMFG-E8) followed by stimulation with LPS in RAW264.7 cells and in peritoneal macrophages, isolated from wild-type (WT) or MFG-E8(-/-) mice. RAW264.7 cells and mouse peritoneal macrophages treated with rmMFG-E8 significantly downregulated LPS-induced TNF-α mRNA by 25% and 24%, and protein levels by 29% and 23%, respectively (P<0.05). Conversely, peritoneal macrophages isolated from MFG-E8(-/-) mice produced 28% higher levels of TNF-α, as compared to WT mice when treated with LPS. In in vivo, endotoxemia induced by intraperitoneal injection of LPS (5 mg/kg BW), at 4 h after induction, serum level of TNF-α was significantly higher in MFG-E8(-/-) mice (837 pg/mL) than that of WT (570 pg/mL, P<0.05). To elucidate the direct anti-inflammatory effect of MFG-E8, we examined STAT3 and its target gene, SOCS3. Treatment with rmMGF-E8 significantly induced pSTAT3 and SOCS3 in macrophages. Similar results were observed in in vivo treatment of rmMFG-E8 in peritoneal cells and splenic tissues. Pre-treatment with rmMFG-E8 significantly reduced LPS-induced NF-κB p65 contents. These data clearly indicated that rmMFG-E8 upregulated SOCS3 which in turn interacted with NF-κB p65, facilitating negative regulation of TLR4 signaling for LPS-induced TNF-α production. Our findings strongly suggest that MFG-E8 is a direct anti-inflammatory molecule, and that it could be developed as a therapy in attenuating inflammation and tissue injury.  相似文献   
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Data mining application to proteomic data from mass spectrometry has gained much interest in recent years. Advances made in proteomics and mass spectrometry have resulted in considerable amount of data that cannot be easily visualized or interpreted. Mass spectral proteomic datasets are typically high dimensional but with small sample size. Consequently, advanced artificial intelligence and machine learning algorithms are increasingly being used for knowledge discovery from such datasets. Their overall goal is to extract useful information that leads to the identification of protein biomarker candidates. Such biomarkers could potentially have diagnostic value as tools for early detection, diagnosis, and prognosis of many diseases. The purpose of this review is to focus on the current trends in mining mass spectral proteomic data. Special emphasis is placed on the critical steps involved in the analysis of surface-enhanced laser desorption/ionization mass spectrometry proteomic data. Examples are drawn from previously published studies and relevant data mining terminology and techniques are exlained.  相似文献   
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Sorghum is largely grown for food, fodder and for biofuel production in semi-arid regions where the drought or high temperature or their combination co-occur. Plant microRNAs (miRNAs) are integral to the gene regulatory networks that control almost all biological processes including adaptation to stress conditions. Thus far, plant miRNA profiles under separate drought or heat stresses have been reported but not under combined drought and heat. In this study, we report miRNA profiles in leaves of sorghum exposed to individual drought or heat or their combination. Approximately 29 conserved miRNA families represented by 80 individual miRNAs, 26 families represented by 47 members of less conserved or sorghum-specific miRNA families as well as 8 novel miRNA families have been identified. Of these, 25 miRNAs were found to be differentially regulated in response to stress treatments. The comparative profiling revealed that the miRNA regulation was stronger under heat or combination of heat and drought compared to the drought alone. Furthermore, using degradome sequencing, 48 genes were confirmed as targets for the miRNAs in sorghum. Overall, this study provides a framework for understanding of the miRNA-guided gene regulations under combined stresses.

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