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Coexistence of predominantly nonculturable rhizobia with diverse, endophytic bacterial taxa within nodules of wild legumes 总被引:1,自引:0,他引:1
Muresu R Polone E Sulas L Baldan B Tondello A Delogu G Cappuccinelli P Alberghini S Benhizia Y Benhizia H Benguedouar A Mori B Calamassi R Dazzo FB Squartini A 《FEMS microbiology ecology》2008,63(3):383-400
A previous analysis showed that Gammaproteobacteria could be the sole recoverable bacteria from surface-sterilized nodules of three wild species of Hedysarum. In this study we extended the analysis to eight Mediterranean native, uninoculated legumes never previously investigated regarding their root-nodule microsymbionts. The structural organization of the nodules was studied by light and electron microscopy, and their bacterial occupants were assessed by combined cultural and molecular approaches. On examination of 100 field-collected nodules, culturable isolates of rhizobia were hardly ever found, whereas over 24 other bacterial taxa were isolated from nodules. None of these nonrhizobial isolates could nodulate the original host when reinoculated in gnotobiotic culture. Despite the inability to culture rhizobial endosymbionts from within the nodules using standard culture media, a direct 16S rRNA gene PCR analysis revealed that most of these nodules contained rhizobia as the predominant population. The presence of nodular endophytes colocalized with rhizobia was verified by immunofluorescence microscopy of nodule sections using an Enterobacter-specific antibody. Hypotheses to explain the nonculturability of rhizobia are presented, and pertinent literature on legume endophytes is discussed. 相似文献
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Yunxia Fang Jiang Hu Jie Xu Haiping Yu Zhenyuan Shi Guosheng Xiong Li Zhu Dali Zeng Guangheng Zhang Zhenyu Gao Guojun Dong Meixian Yan Longbiao Guo Yonghong Wang Qian Qian 《植物学报(英文版)》2015,57(2):151-161
The aerial parts of higher plants are generated from the shoot apical meristem(SAM). In this study, we isolated a small rice(Oryza sativa L.) mutant that showed premature termination of shoot development and was named mini rice 1(mini1). The mutant was first isolated from a japonica cultivar Zhonghua11(ZH11) subjected to ethyl methanesulfonate(EMS)treatment. With bulked segregant analysis(BSA) and map-based cloning method, Mini1 gene was finally fine-mapped to an interval of 48.6 kb on chromosome 9. Sequence analyses revealed a single base substitution from G to A was found in the region, which resulted in an amino acid change from Gly to Asp.The candidate gene Os09g0363900 was predicted to encode a putative adhesion of calyx edges protein ACE(putative HOTHEAD precursor) and genetic complementation experiment confirmed the identity of Mini1. Os09g0363900 contains glucose-methanol-choline(GMC) oxidoreductase and NAD(P)-binding Rossmann-like domain, and exhibits high similarity to Arabidopsis HOTHEAD(HTH). Expression analysis indicated Mini1 was highly expressed in young shoots but lowly in roots and the expression level of most genes involved in auxin biosynthesis and signal transduction were reduced in mutant.We conclude that Mini1 plays an important role in maintaining SAM activity and promoting shoot development in rice. 相似文献
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Xiaojian Wang Qian Yang Minyong Li Dali Yin Qidong You 《Journal of molecular modeling》2010,16(9):1529-1537
It is widely acknowledged that the H1 receptor antagonists have important therapeutic significance in the treatment of various allergic disorders, but little was
known about the binding mode between the receptor and antagonists since the crystal structure of G-protein coupling receptors
(GPCRs) were hard to obtain. In this paper, a theoretical three-dimensional model of human histamine H1 receptor (HHR1) was developed on the basis of recently reported high resolution structures of human A2A adenosine receptor, human β2-adrenoceptor and turkey β1-adrenoceptor. Furthermore, three representative H1 receptor antagonists were chosen for docking studies. Subsequently, a qualitative pharmacophore model was developed by Hiphop
algorithm based on the docking conformations of these three antagonists. In this paper, active environment, certain key residues,
and the corresponding pharmacophore features of H1 receptor were identified by such combinations of receptor-based and ligand-based approaches, which would give sufficient
guidance for the rational design of novel antihistamine agents. 相似文献
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Hüiwan Han Dali Shao Jinyi Wu Germaine Cornélissen Franz Halberg 《Cell biochemistry and biophysics》1991,18(3):217-229
An earlier demonstration of a circadian rhythm in rat atria by others is complemented herein by observations in culture: A single murine myocardial cell and two sets of grouped cells beating in culture for several days reveal several features of an anticipated, presumably built-in spectrum of multifrequency rhythms and trends, the chronome. Circadian and about 12-h (circasemidian) components are modulated by an approximately 84-h (circasemiseptan) component, which cannot be separated from trends in view of the brevity of the series. The circumstance under which the culture is aging and in which fibroblasts proliferate is a further complication that limits the findings to a single cycle reproduced in three separate cultures. Whether it is a rhythm that repeats itself or a response to placement into culture, an approximately 3.5-d component in the beating of myocardial cells in culture is to be aligned with a very prominent similar component found in the incidence of 85,819 human myocardial infarctions. 相似文献
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