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991.
Volatiles from the epicuticular wax of watercress were collected by ether washing and examined using gas chromatographic and mass spectrometric analysi  相似文献   
992.
Ciliated tracheal epithelia cell cultures were investigated immunocytochemically with anti-tubulin and colloidal gold. When rabbit tracheal cultures were fixed in paraformaldehyde, treated with acetone, anti-tubulin and a second antibody coupled to FITC, fluorescence was associated with cytoskeletal and axonemal microtubules. Cilia covering the apical surface of the ciliated tracheal cells fluoresced very brightly thus facilitating identification of this cell type. Electron microscopy of tracheal cultures fixed as above, treated with Triton-X 100 and incubated in anti-tubulin and protein A coupled to colloidal gold resulted in the highly specific localization of tubulin in ciliary axonemes and basal bodies. Omission of primary or secondary antibody resulted in extremely low levels of fluorescence while no colloidal gold particles could be detected in cultures at the electron microscopy level when rabbit anti-tubulin was omitted.  相似文献   
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The distribution of regular secondary structures, viz. α-helices and β-strands, along the length of over 70 properties whose secondary structural details have been reported, has been analysed. The occurrence of these regular structures tends to be a maximum at the N- and C-termini. Our analysis suggests that both these free ends could possibly serve as nucleating centers for secondary structures and could play an important role in the folding of proteins.  相似文献   
995.
The flavonoids of five Geranium, fourteen Erodium and four Monsonia species were studied. Quercetin was the most common aglycone with lesse  相似文献   
996.
It was shown that at a continuously increased level of endogenous glucocorticoids (injection of ACTH) in thymectomized and B mice the degree of inhibition of CFUs migration, that was observed in T-deficient mice without ACTH injection, did not increase. With T-deficiency the stimulatory effect of the hypocorticoid state (adrenalectomy) on the CFUs migration persisted but was less pronounced than in animals with intact thymus.  相似文献   
997.
The 5'-terminal 597 base-pairs (bp) of the Sprague-Dawley rat 18S ribosomal RNA gee and 10 bp of the adjoining transcribed spacer have been sequenced. Previously sequenced 10 large oligonucleotides of rat 18S RNA were located in this region. This mammalian sequence has been compared with the known sequences of yeast and frog 18S rDNA's. The analysis indicates that 534 bp of the 597 bp (89%) are conserved between rat and frog sequences but only 75% of the nucleotides are conserved between rat and yeast in this region. Two large and two small sections have been identified where insertions have been introduced during evolution. Of these 58 bp long inserted sections of the rat rDNA sequence, 50 bp (86%) were G-C base-pairs.  相似文献   
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