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103.
线艺建兰的组织培养和快速繁殖(简报) 总被引:1,自引:0,他引:1
以线艺建兰茎尖、腋芽为外植体,接种在1/2MS 6-BA 3.0mg/L NAA 0.3mg/L培养基上形成原球茎,原球茎在1/2MS 6-BA 0.1mg/L NAA 1.0mg/L培养基上可大量增殖,并伸长生长形成丛生型根状茎;根状茎在MS 6-BA 2.0mg/L PP333 1.0mg/L NAA 0.5mg/L培养基上可分化成小苗,分化率达46.3%;小苗在MS IBA 1.0mg/L GA 0.5mg/L 香蕉泥100g/L的培养基上生根壮苗,生根率达100%. 相似文献
104.
SUMMARY: State and federal natural resource management agencies often collect age-structured harvest data. These data represent finite realizations of stochastic demographic and sampling processes and have long been used by biologists to infer population trends. However, different sources of data have been combined in ad hoc ways and these methods usually failed to incorporate sampling error. In this article, we propose a "hidden process" (or state-space) model for estimating abundance, survival, recovery rate, and recruitment from age-at-harvest data that incorporate both demographic and sampling stochasticity. To this end, a likelihood for age-at-harvest data is developed by embedding a population dynamics model within a model for the sampling process. Under this framework, the identification of abundance parameters can be achieved by conducting a joint analysis with an auxiliary data set. We illustrate this approach by conducting a Bayesian analysis of age-at-harvest and mark-recovery data from black bears (Ursus americanus) in Pennsylvania. Using a set of reasonable prior distributions, we demonstrate a substantial increase in precision when posterior summaries of abundance are compared to a bias-corrected Lincoln-Petersen estimator. Because demographic processes link consecutive abundance estimates, we also obtain a more realistic biological picture of annual changes in abundance. Because age-at-harvest data are often readily obtained, we argue that this type of analysis provides a valuable strategy for wildlife population monitoring. 相似文献
105.
Niswender CM Lebois EP Luo Q Kim K Muchalski H Yin H Conn PJ Lindsley CW 《Bioorganic & medicinal chemistry letters》2008,18(20):5626-5630
This letter describes the synthesis and SAR, developed through an iterative analogue library approach, of an mGluR4 positive allosteric modulator lead based on a pyrazolo[3,4-d]pyrimidine scaffold. Despite tremendous therapeutic potential, Compound 7, VU0080421, and related congeners represent only a handful of mGluR4 positive allosteric modulators ever described. 相似文献
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Analysis of the Endophytic Actinobacterial Population in the Roots of Wheat (Triticum aestivum L.) by Terminal Restriction Fragment Length Polymorphism and Sequencing of 16S rRNA Clones 总被引:3,自引:0,他引:3 下载免费PDF全文
The endophytic actinobacterial population in the roots of wheat grown in three different soils obtained from the southeast part of South Australia was investigated by terminal restriction fragment length polymorphism (T-RFLP) analysis of the amplified 16S rRNA genes. A new, validated approach was applied to the T-RFLP analysis in order to estimate, to the genus level, the actinobacterial population that was identified. Actinobacterium-biased primers were used together with three restriction enzymes to obtain terminal restriction fragments (TRFs). The TRFs were matched to bacterial genera by the T-RFLP Analysis Program, and the data were analyzed to validate and semiquantify the genera present within the plant roots. The highest diversity and level of endophytic colonization were found in the roots of wheat grown in a dark loam from Swedes Flat, and the lowest were found in water-repellent sand from Western Flat. This molecular approach detected a greater diversity of actinobacteria than did previous culture-dependent methods, with the predominant genera being Mycobacterium (21.02%) in Swedes Flat, Streptomyces (14.35%) in Red Loam, and Kitasatospora (15.02%) in Western Flat. This study indicates that the soil that supported a higher number of indigenous organisms resulted in wheat roots with higher actinobacterial diversity and levels of colonization within the plant tissue. Sequencing of 16S rRNA clones, obtained using the same actinobacterium-biased PCR primers that were used in the T-RFLP analysis, confirmed the presence of the actinobacterial diversity and identified a number of Mycobacterium and Streptomyces species. 相似文献
108.
The GnRH receptor is coupled to G proteins of the families Gq and G11. Gq and G11 coupling leads to intracellular signaling through the phospholipase C pathway. GnRHR coupling to other G proteins is controversial. This study provides evidence that G protein families Gs, Gi, Gq and G11 complete for binding with the GnRHR. We quantified interactions of over-expressed G proteins with GnRHR by a competitive binding approach, using measurements of second messengers, IP and cAMP. Transient co-transfection of HEK293 cells with human WT GnRHR and with stimulatory and inhibitory G proteins (Gq, G11 and Gs, Gi) led to either production or inhibition of total inositol phosphate (IP) production, depending on the G protein that was over-expressed. Studies were conducted in different human (COS7, HeLa) and rodent-derived (CHO-K1, GH3) cell lines in order to confirm that G protein promiscuity observed with the GnRHR was not limited to a particular cell type. 相似文献
109.
We have recently reported that CoASH is the major low-molecular weight thiol in Bacillus anthracis [Nicely, N. I. , Parsonage, D., Paige, C., Newton, G. L., Fahey, R. C., Leonardi, R., Jackowski, S., Mallett, T. C., and Claiborne, A. (2007) Biochemistry 46, 3234-3245], and we have now characterized the kinetic and redox properties of the B. anthracis coenzyme A-disulfide reductase (CoADR, BACoADR) and determined the crystal structure at 2.30 A resolution. While the Staphylococcus aureus and Borrelia burgdorferi CoADRs exhibit strong preferences for NADPH and NADH, respectively, B. anthracis CoADR can use either pyridine nucleotide equally well. Sequence elements within the respective NAD(P)H-binding motifs correctly reflect the preferences for S. aureus and Bo. burgdorferi CoADRs, but leave questions as to how BACoADR can interact with both pyridine nucleotides. The structures of the NADH and NADPH complexes at ca. 2.3 A resolution reveal that a loop consisting of residues Glu180-Thr187 becomes ordered and changes conformation on NAD(P)H binding. NADH and NADPH interact with nearly identical conformations of this loop; the latter interaction, however, involves a novel binding mode in which the 2'-phosphate of NADPH points out toward solvent. In addition, the NAD(P)H-reduced BACoADR structures provide the first view of the reduced form (Cys42-SH/CoASH) of the Cys42-SSCoA redox center. The Cys42-SH side chain adopts a new conformation in which the conserved Tyr367'-OH and Tyr425'-OH interact with the nascent thiol(ate) on the flavin si-face. Kinetic data with Y367F, Y425F, and Y367,425F BACoADR mutants indicate that Tyr425' is the primary proton donor in catalysis, with Tyr367' functioning as a cryptic alternate donor in the absence of Tyr425'. 相似文献
110.
中国红豆杉细胞紫杉醇合成期与非紫杉醇合成期基因表达差异初步分析 总被引:1,自引:0,他引:1
紫杉醇 (Paclitaxel,商品名为Taxol)是存在于红豆杉属(Taxussp .)植物中的一种四环二萜酰胺类化合物 ,因其具有广谱强效的抗癌活性和独特的抗癌机理而倍受人们关注。然而 ,紫杉醇天然资源十分有限 ,自 1992年美国食品与药物管理局 (FDA)批准紫杉醇用于癌症的临床治疗以来 ,其供需矛盾日益尖锐[1 ] 。目前 ,普遍认为采用红豆杉细胞悬浮培养生产紫杉醇是解决其药源紧缺问题的最佳途径之一。迄今为止 ,在红豆杉细胞的代谢规律和培养方面均取得一定成果 ,但前景仍不容乐观 ,离工业化大规模生产还有相当大的距离 ,主要… 相似文献