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21.
Two new beta-xylosyl derivatives of ginsenoside Re, 20(S)-protopanaxatriol 6-O-alpha-L-rhamnopyranosyl-(1 --> 2)-[beta-D-xylopyranosyl-(1 --> 4)]-beta-D-glucopyranosyl-20-O-beta-D-glucopyranoside and 20(S)-protopanaxatriol 6-O-alpha-L-rhamnopyranosyl-(1 --> 2)-[beta-D-xylopyranosyl-(1 --> 6)]-beta-D-glucopyranosyl-20-O-beta-D-glucopyranoside, were respectively synthesized from p-nitrophenyl beta-D-xylopyranoside and phenyl beta-D-xylopyranoside as donors and ginsenoside Re as the acceptor in 25% acetone and acetonitrile by a cellulase preparation from Trichoderma viride and a beta-galactosidase preparation from Aspergillus oryzae. The latter enzyme preparation also catalyzed the hydrolysis of ginsenoside Re to the minor saponin, ginsenoside Rg2. 相似文献
22.
Curt Koßwig 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1932,4(1):22-32
Ohne Zusammenfassung 相似文献
23.
Robin S. Manasse Maureen L. Stanton 《Evolution; international journal of organic evolution》1991,45(4):883-890
We present evidence that extreme seed size variation in fruits of Crinum erubescens (range: 0.1 to 66.5 g per seed) occurs when mating pairs are inbred, either from selfing or biparental inbreeding. Several relatively uniform seeds of intermediate size are produced when pollen from several pollen donors is applied simultaneously to a flower. Selfed fruits and some fruits pollinated with a single pollen donor produce both large and small seeds, although selfed fruits produce fewer seeds than outcrossed fruit. These results are contrary to the hypothesis that variation in seed size is attributable to either pollen competition or differential allocation of maternal resource to seeds of different genotypes. 相似文献
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25.
Thomas J. V. Higgins Larry R. Beach Donald Spencer Peter M. Chandler Peter J. Randall Robert J. Blagrove Alexander A. Kortt Robin E. Guthrie 《Plant molecular biology》1987,8(1):37-45
Summary Pea albumin 2 (PA2:Mr26000) is a major component of the albumin fraction derived from aqueous salt extracts of pea seed. Sodium dodecylsulfate-polyacrylamide gel electrophoresis and chromatography on DEAE-Sephacel resolve PA2 into two closely related components (PA2a and PA2b). A cDNA clone coding for one of these components has been sequenced and the deduced amino acid sequence compared with partial, chemically-determined sequences for cyanogen bromide peptides from both PA2 components. Complete amino acid sequences were obtained for the C-terminal peptides. The PA2 molecule of 230 amino acids contains four imperfect repeat sequences each of approximately 57 amino acids in length.The combined sequence data, together with a comparison of PA2-related polypeptides produced in vitro and in vivo, indicate that PA2 is synthesized without a signal sequence and does not undergo significant post-translational modification. Although both forms of PA2 contain Asn-X-Thr consensus sequences, neither form is glycosylated. Accumulation of PA2 contributes approximately 11% of the sulfur-amino acids in pea seeds (cysteine plus methionine equals 2.6 residues percent). Suppression of levels of PA2 polypeptides and their mRNAs in developing seeds of sulfur-deficient plants is less marked than that for legumin, in spite of the lower content of sulfur-amino acids in legumin. 相似文献
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Y C Kong W M Keung T T Yip K M Ko S W Tsao M H Ng 《Comparative biochemistry and physiology. B, Comparative biochemistry》1987,87(2):221-226
1. An epidermal growth factor (EGF)-like activity was detected and partially purified from swiftlet's nest extract. 2. The partially purified EGF-like activity was able to (a) generate competitive binding curves parallel to the standard curves in radioreceptor assay and (b) stimulate thymidine incorporation in quiescent culture of 3T3 fibroblasts and the latter activity can be suppressed by mouse EGF antibody. 3. Partial characterization of the EGF-like activity in terms of pI, molecular weight and its behavior on gel filtration column suggest that it bears similar physical properties to the EGFs isolated from the mouse and the shrew. 相似文献
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Abstract The genomes of DNA phage ΦX174 and of RNA phage MS2 each encode a single lysis protein, E protein and L protein, respectively. Based on the known DNA and protein sequences, and with the aid of structural predictions of the proteins, a chimeric gene was constructed. The resulting protein was composed of the N-terminal sequence of E protein and the C-terminal sequence of L protein. The truncated E and L polypeptides used in this construction were functionally inactive. However, the chimeric gene product had very high lysis-inducing activity. This construction is an example which could be extended to the engineering of other lysis proteins designed with specific biotechnological processes in mind. 相似文献