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991.
Studying rhizobia in the root nodules of Sphaerophysa salsula (Pall.) DC in the northwest of China, we obtained five strains classified as genus Rhizobium on the basis of their 16S rRNA gene sequences. The sequence similarity of strain CCNWQTX14T with the most related species was 99.0%. Further phylogenetic analysis of housekeeping genes (recA and atpD) suggested the five strains comprised a novel lineage within Rhizobium. The nifH and nodD gene sequences of CCNWQTX14T were phylogenetically closely related with those of Sinorhizobium kummerowiae and R. sphaerophysae, respectively. The five strains isolated from different places were also distinct from related Rhizobium species using ERIC fingerprint profiles. The DNA–DNA hybridization value was 41.8% between CCNWQTX14T and Rhizobium sphaerophysae CCNWGS0238T. Our novel strains were only able to form effective nodules on its original host Sphaerophysa salsula. Our data showed that the five Rhizobium strains formed a unique genomic species, for which a novel species Rhizobium
helanshanense sp. nov. is proposed. The type strain is CCNWQTX14T (=ACCC 16237T =HAMBI 3083T). 相似文献
992.
Dandan Zhang Guangqiao Liu Jiaying Xue Jizhong Lou Knud H. Nierhaus Weimin Gong Yan Qin 《Nucleic acids research》2012,40(21):10851-10865
Translational GTPases (trGTPases) regulate all phases of protein synthesis. An early event in the interaction of a trGTPase with the ribosome is the contact of the G-domain with the C-terminal domain (CTD) of ribosomal protein L12 (L12-CTD) and subsequently interacts with the N-terminal domain of L11 (L11-NTD). However, the structural and functional relationships between L12-CTD and L11-NTD remain unclear. Here, we performed mutagenesis, biochemical and structural studies to identify the interactions between L11-NTD and L12-CTD. Mutagenesis of conserved residues in the interaction site revealed their role in the docking of trGTPases. During docking, loop62 of L11-NTD protrudes into a cleft in L12-CTD, leading to an open conformation of this domain and exposure of hydrophobic core. This unfavorable situation for L12-CTD stability is resolved by a chaperone-like activity of the contacting G-domain. Our results suggest that all trGTPases—regardless of their different specific functions—use a common mechanism for stabilizing the L11-NTD•L12-CTD interactions. 相似文献
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Juanfang Liu Xiaodong Yan Ling Li Yi Zhu Kefeng Qin Linfu Zhou Dong Sun Xiaohui Zhang Ruidong Ye Gang Zhao 《Neurochemical research》2012,37(12):2738-2747
Alzheimer??s disease is a neurodegenerative disease characterized by the production of ??-amyloid proteins and hyperphosphorylation of tau protein. Inflammation and apoptotic severity were highly correlated with earlier age at onset of Alzheimer??s disease and were also associated with cognitive decline. This study aims to examine whether the traditional Chinese medicine ginsennoside Rd could prevent cognitive deficit and take neuroprotective effects in ??-amyloid peptide 1?C40-induced rat model of Alzheimer??s disease. To produce Alzheimer??s disease animal model, aggregated ??-amyloid peptide 1?C40 injected into hippocampus bilaterally. Ginsennoside Rd protected their cognitive impairment and improved their memory function by daily intraperitoneal injection for 30?days consecutively. In addition, ginsennoside Rd alleviated the inflammation induced by ??-amyloid peptide 1?C40. Furthermore, ginsennoside Rd played a role in the down-regulation of caspase-3 proteins and reduced the apoptosis that normally followed ??-amyloid peptide 1?C40 injection. The results of this study showed that the pretreatment of ginsennoside Rd had neuroprotective effects in ??-amyloid peptide 1?C40-induced AD model rat. 相似文献
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Fan Y Shi Y Liu S Mao R An L Zhao Y Zhang H Zhang F Xu G Qin J Yang J 《Cellular signalling》2012,24(7):1381-1389
Protein kinases are important regulators of intracellular signal transduction pathways and play critical roles in diverse cellular processes. TAK1, a member of the MAPKKK family, is essential for TNFα-induced NF-κB activation. Phosphorylation and Lys(63)-linked polyubiquitination (polyUb) of TAK1 are critical for its activation. However, whether TAK1 is regulated by polyubiquitination-mediated protein degradation after its activation remains unknown. Here we report that TNFα induces TAK1 Lys(48) linked polyubiquitination and degradation at the later time course. Furthermore, we provide direct evidence that TAK1 is modified by Lys(48)-linked polyubiquitination at lysine-72 by mass spectrometry. A K72R point mutation on TAK1 abolishes TAK1 Lys(48)-linked polyubiquitination and enhances TAK1/TAB1 co-overexpression-induced NF-κB activation. As expected, TAK1 K72R mutation inhibits TNFα-induced Lys(48)-linked TAK1 polyubiquitination and degradation. TAK1 K72R mutant prolongs TNFα-induced NF-κB activation and enhances TNFα-induced IL-6 gene expression. Our findings demonstrate that TNFα induces Lys(48)-linked polyubiquitination of TAK1 at lysine-72 and this polyubiquitination-mediated TAK1 degradation plays a critical role in the downregulation of TNFα-induced NF-κB activation. 相似文献
999.
Bone has the ability to adapt its structure in response to the mechanical environment as defined as Wolff's Law. The alignment of trabecular structure is intended to adapt to the particular mechanical milieu applied to it. Due to the absence of normal mechanical loading, it will be extremely important to assess the anisotropic deterioration of bone during the extreme conditions, i.e., long term space mission and disease orientated disuse, to predict risk of fractures. The propagation of ultrasound wave in trabecular bone is substantially influenced by the anisotropy of the trabecular structure. Previous studies have shown that both ultrasound velocity and amplitude is dependent on the incident angle of the ultrasound signal into the bone sample. In this work, seven bovine trabecular bone balls were used for rotational ultrasound measurement around three anatomical axes to elucidate the ability of ultrasound to identify trabecular orientation. Both ultrasound attenuation (ATT) and fast wave velocity (UV) were used to calculate the principal orientation of the trabecular bone. By comparing to the mean intercept length (MIL) tensor obtained from μCT, the angle difference of the prediction by UV was 4.45°, while it resulted in 11.67° angle difference between direction predicted by μCT and the prediction by ATT. This result demonstrates the ability of ultrasound as a non-invasive measurement tool for the principal structural orientation of the trabecular bone. 相似文献
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