共查询到20条相似文献,搜索用时 15 毫秒
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World Journal of Microbiology and Biotechnology - 相似文献
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M. G. M. Van Creij J. L. van Went D. M. F. J. Kerckhoffs 《Sexual plant reproduction》1997,10(4):241-249
The development of the embryo and endosperm has been investigated in an intraspecific Tulipa gesneriana cross and in the incongruent cross T. gesneriana ×T. agenensis at intervals of 10 days, from 12 to 82 days after pollination (DAP). In both tulip crosses, the zygote gives rise to an apparently
undifferentiated cell mass, the proembryonal cell mass, on which a suspensor then develops. Subsequently, a globular embryo
is formed on top of the suspensor. This embryo finally elongates, giving rise to a spindle-shaped embryo. The cellular endosperm
fills the whole embryo sac in mature seeds, except for a region immediately around the embryo. In both crosses, aberrant developments
were found. In the intraspecific T. gesneriana cross, the pollen tubes did not open in a number of ovules. In other ovules, the pollen tubes seemed to have opened, but an
embryo or endosperm was not found or only endosperm was observed. In the cross T. gesneriana ×T. agenensis, fewer pollen tubes entered the ovules than in the intraspecific T. gesneriana cross. The ovules with embryo and endosperm formation of the incongruent interspecific cross showed, in general, retarded
development in comparison with the intraspecific T. gesneriana cross. The first globular embryos and spindle-shaped embryos were found at the later fixation dates and the relatively lower
number of spindle-shaped embryos at 82 DAP had a shorter average length. The number of ovules with deformations in embryo
and/or endosperm development was also higher in the cross T. gesneriana × T. agenensis in comparison with the intraspecific T. gesneriana cross. Between 87% and 100% of the ovules with embryo and endosperm development showed normal development in the intraspecific
T. gesneriana cross, while in the incongruent interspecific cross, from 22 DAP, between 17% and 56% of the ovules showed normal development.
Of those ovules with aberrations in embryo and/or endosperm formation, about 80% had a deformed endosperm, of which more than
50% also contained a deformed embryo. Embryos of the incongruent cross might be saved by the application of embryo rescue
techniques.
Received: 10 December 1996 / Revision accepted: 23 April 1997 相似文献
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T cell subpopulations (Tμ and Tγ cells) were examined in the peripheral blood from fourteen patients with mycosis fungoides and Sézary syndrome. One patient with Sézary syndrome having low lymphocyte count had higher proportions of Tγ cells when compared to controls while the other with high lymphocyte count (75% Sézary cells) lacked Tγ cells and had normal proportions of Tμ cells. T cells from a third patient with Sézary syndrome having high lymphocyte count (95% Sézary cells) lacked almost completely both Tμ and Tγ cells. Three of eleven patients with mycosis fungoides had a high proportion of Tγ cells and one had a high proportion of Tμ cells. Study of T cells in the peripheral blood, lymph nodes, and bone marrow from two patients with mycosis fungoides demonstrated that the quantitative abnormality of tμ and Tγ cells is shared by the peripheral blood and bone marrow and not by the lymph nodes. Heterogeneity of T cells subsets in mycosis fungoides appears to be in non-malignant T cells. However, in Sézary syndrome malignant Sézary T cells demonstrate heterogeneity with regard to receptors for IgM (Tμ) and IgG (Tγ). 相似文献
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《Bioscience, biotechnology, and biochemistry》2013,77(4):589-594
When Bacillus sp. K40T was cultured in the presence of L-fucose, 1,2-α-L-fucosidase was found to be produced specifically in the culture fluid. The enzyme was purified to homogeneity from a culture containing only L-fucose by chromatography on hydroxylapatite and chromatofocusing. The molecular weight of the enzyme was estimated to be 200,000 by gel filtration on Sephadex G-200. The enzyme was optimal at pH 5.5–7.0 and was stable at pH 6.0–9.0. The enzyme hydrolyzed the α(1 → 2)-L-fucosidic linkages in various oligosaccharides and glycoproteins such as lacto-N-fucopentaose (LNF)-I 〈O-α-L-fucose-(1 → 2)-O-β-D-galactose-(1 → 3)-N-acetyl-O-β-D-glucosamine-(1 → 3)-O-β-D-galactose-(1 → 4)-D-glucose〉, porcine gastric mucin, and porcine submaxillary mucin. The enzyme also acted on human erythrocytes, which was confirmed by the hemagglutination test using Ulex anti-H lectin. The enzyme did not hydrolyze α(1 → 3)-, α-(1 → 4)- and α-(1 → 6)-L-fucosidic linkages in LNF-III 〈O-β-D-galactose-(1 → 4)[O-α-L-fucose-(1 → 3)-]-N-acetyl-O-β-D-glucosamine-(1 → 3)-O-β-D-galactose-(1 → 4)-D-glucose〉, LNF-II 〈O-β-D-galactose-(1 → 3)[O-α-L-fucose-(1 → 4)-]-N-acetyl-O-β-D-galactose-(1 → 3)-O-β-D-galactose-(1 → 4)-D-glucose〉 or 6-O-α-L-fucopyranosyl-N-acetylglucosamine. 相似文献
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R. S. Gill H. S. Dhaliwal D. S. Multani 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1988,75(6):912-916
Summary Nine Triticum durum — T. monococcum amphiploids (AABBAmAm) were synthesized by chromosome doubling of sterile triploid F1 hybrids involving nine T. durum (AABB) cultivars and a T. monococcum (AmAm) line. The triploid F1 hybrids had a range of 4–7 bivalents and 7–13 univalents per PMC. The synthetic amphiploids, however, showed a high degree of preferential pairing of chromosomes of the A genomes of diploid and tetraploid wheats. The amphiploids were meiotically stable and fully fertile. Superiority of four amphiploids for tiller number per plant, 100-grain weight, protein content and resistance to Karnal bunt demonstrated that these could either be commercially exploited as such after overcoming certain inherent defects or used to introgress desirable genes into durum and bread wheat cultivars. Methods for improvement of these amphiploids are discussed. 相似文献
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