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711.
712.
The development of sensitive and specific solid-phase enzyme immunoassays for gibberellic acid and gibberellins A4 and A7 is reported. The use of antisera of high apparent affinity (Ka over 1010 l mol-1) in conjunction with alkaline phosphatase-labeled gibberellins allows, with minimum procedural effort, the quantitative determination of sub-picogram amounts of these gibberellins. The assays reported here are applicable to most gibberellins and can be set up with 1–1.5 mg of starting material. They represent the most sensitive methods for gibberellin determination known.Abbreviations GA
gibberellin
- GA3
gibberellic acid
- TLC
thin-layer-chromatography 相似文献
713.
Safarali Bahrami Ulrich Plate Rita Dreier Alfred DuChesne Günter-Heinrich Willital Peter Bruckner 《Matrix biology》2001,19(8):707-715
Late cartilage differentiation during endochondral bone formation is a multistep process. Chondrocytes transit through a differentiation cascade under the direction of environmental signals that either stimulate or repress progression from one step to the next. In human costal cartilage, chondrocytes reach very advanced stages of late differentiation and express collagen X. However, remodeling of the tissue into bone is strongly repressed. The second hypertrophy marker, alkaline phosphatase, is not expressed before puberty. Upon sexual maturity, both alkaline phosphatase and collagen X activity levels are increased and slow ossification takes place. Thus, the expression of the two hypertrophy markers is widely separated in time in costal cartilage. Progression of endochondral ossification in this tissue beyond the stage of hypertrophic cartilage appears to be associated with the expression of alkaline phosphatase activity. Costal chondrocytes in culture are stimulated by parathyroid hormone in a PTH/PTHrP receptor-mediated manner to express the fully differentiated hypertrophic phenotype. In addition, the hormone stimulates hypertrophic development even more powerfully through its carboxyterminal domain, presumably by interaction with receptors distinct from PTH/PTHrP receptors. Therefore, PTH can support late cartilage differentiation at very advanced stages, whereas the same signal negatively controls the process at earlier stages. 相似文献
714.
Elmar Robbrecht 《Journal of Biogeography》1996,23(3):311-328
A survey of the distribution of the Rubiaceae from subsaharan African (continental part: 1,900 species in 164 genera; Madagascar: 675 species in 83 genera) is given. Genera are classified in nine major distribution patterns, most of which are further subdivided. General statistics of the data are given, and the patterns are discussed in the light of (i) the phytogeographical literature relating to tropical Africa and (ii) existing evolutionary hypotheses on the Rubiaceae. 相似文献