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71.
72.
G. Wang J. Ji Y-B. Wang H. Hu I. P. King J. W. Snape 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1993,87(5):531-536
Two novel 46-chromosome doubled haploid lines, W66 and M17, derived from separate hexaploid triticale x bread wheat crosses, were characterised using cytological and biochemical markers. Both lines were shown to be relatively stable cytologically, over 11 and 8 generations of selfing, respectively. By examining mitotic and meiotic chromosomes, the stabilities of the two lines were shown to be similar with frequencies of 2n=46 in 74.2–85.5% of cells. However, over selfed generations, the rye chromosomes were shown to have lost some of their heterochromatin, which made it difficult to establish their continued presence using cytological techniques, such as C-banding alone. Cytological evidence from pairing studies, C-banding, and fluorescence in-situ hybridization, showed that both M17 and W66 are wheat/rye multi-addition lines with rye chromosome constitutions of 1R+6R, and 1R+4R, respectively. These conclusions were confirmed by isozyme and storage-protein analysis. 相似文献
73.
用粘粒PJB8为载体,构建了宋内氏痢疾菌I相大质粒基因库。用菌落原位杂交,Western blot方法从文库中筛选到1株表达IpaA,B,C,D 4种蛋白的重组子。经重组质粒酶切和Southern blot等方法对宋内氏菌和福氏2a痢疾菌的侵袭相关基因片段作了初步比较分析。 相似文献
74.
乙烯诱导下草莓果实采后RNA代谢与蛋白质合成活性的变化 总被引:3,自引:0,他引:3
草莓草果实在乳白时期采收(开花后约40d),分别用10μl/L,50μl/L和100μl/L的外源乙烯进行处理。处理后的果实大分子RNA和poly(A)+RNA水平以及poly(A)+RNA与总RNA的比例均有增高。果实体内RNA酶活性和体外蛋白质的合成水平也升高。乙烯很可能是促进草莓果实成熟衰老的因素之一。 相似文献
75.
KOWICHI JIMBOW DONG LUO HUA CHEN HIROYUKI HARA MU HYOUNG LEE 《Pigment cell & melanoma research》1994,7(5):311-319
In order to better understand the cascade of melanogenic events in melanocytes, this report has introduced our two recent approaches for the expression of melanogenesis/or melanosome-associated genes and encoded proteins in melanocytes (melanoma cells) after repeated exposure to UV -B and after cotransfection of two human genes, i.e., tyrosinase and tyrosinase-related protein-1 (TRP-1). Repeated exposure of UV B (2.5–5.0 mJ/cm2) caused not only upregulation of tyrosinase and TRP-1 genes but also coordinated increase in the gene and protein synthesis expression of Lamp-1 (lysosome-associated membrane protein-1). When COS-7 kidney cells and amelanotic melanoma (C32 and SKMEL-24) and melanotic melanoma (G361 and SK-MEL-23) cells were exposed to cotransfection of human tyrosinase and TRP-1 cDNAs, there was also an increased expression of Lamp-1 mRNA and protein along with tyrosinase activation and new melanin synthesis. Importantly, single transfectants of human tyrosinase cDNA revealed marked cellular degeneration, whereas this degeneration was not seen in single transfectants of TRP-1 cDNA or cotransfectants of human tyrosinase and TRP-1 cDNAs, indicating that TRP-1 prevented, along with Lamp-1, programmed death of melanocytes after transfection of tyrosinase gene. The coordinated expression of TRP-1 and Lamp-1 was further confirmed by antisense oligodeoxynucleotide hybridization experiment against Lamp-1 gene, showing the decreased expression of TRP-1 as identified by three different types of anti-TRP-1 monoclonal antibodies. We propose therefore that human tyrosinase and TRP-l, when activated or expressed together, will coordinate to upregulate the mRNA expression and protein synthesis of Lamp-1. The Lamp-1 molecules will, in turn, cover the inner surface of melanosomal membrane, together with TRP-1 molecules, thus protecting the melanosomal membrane from toxic melanin intermediates generated during melanogenesis in the presence of active tyrosinase. In contrast, the expression of other lysosome-related proteins, e.g., β-galactosidase and CD63 is not stimulated in new melanogenesis. 相似文献
76.
77.
物种保护信息管理系统的开发应用 总被引:9,自引:1,他引:8
在英文物种、生境和保护区管理系(MASS 3.1)的基础上,研究并改编完成了其中文系统软件包(CMASS 2.0),并用此中文系统软件包建立了中国自然保护区信息库、中国保护动物信息库、中国濒危动物信息库、中国兽类信息库、中国鸟类信息库,这些库的建立对我国野生动物保护具有重要意义。 相似文献
78.
Seasonal Variations in Rubber Biosynthesis, 3-Hydroxy-3-Methylglutaryl-Coenzyme A Reductase,and Rubber Transferase Activities in Parthenium argentatum in the Chihuahuan Desert 总被引:1,自引:0,他引:1 下载免费PDF全文
The rubber content and the activities of enzymes in the polyisoprenoid pathway in Parthenium argentatum (guayule) were examined throughout the growing season in field plots in the Chihuahuan Desert. The rubber content of the plants was low in July and August and slowly increased until October. From October to December there was a rapid increase in rubber formation (per plant) from 589.0 mg to 4438.0 mg. The percentage of rubber in the plants increased from 0.7% (mg/g dry weight) in August and 1.27% in October to 5.5% in December. The rapid increase in rubber formation may result from exposing the plants to low temperatures of 5 to 7[deg]C. The activity of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) was 21.1 nmol mevalonic acid (MVA) h-1 g-1 fresh weight in the bark of the lower stems in June during seedling growth and decreased to 5.1 nmol MVA h-1g-1 fresh weight in July and 2.9 nmol MVA h-1 g-1 fresh weight in September. From October to December, the activity increased from 5.0 to 29.9 nmol MVA h-1 g-1 fresh weight. The activity of rubber transferase was 65.5 nmol isopentenyl pyrophosphate (IPP) h-1 g-1fresh weight in the bark in September and increased to 357.5 nmol IPP h-1 g-1 fresh weight in December. The rapid increase in the activities of HMGR and rubber transferase coincided with the rapid increase in rubber formation. The activities of MVA kinase and IPP isomerase did not significantly increase in the fall and winter. A tomato HMGR-1 cDNA probe containing a highly conserved C-terminal region of HMGR genes hybridized at low stringency with several bands on blots of HindIII-digested genomic DNA from guayule. In northern blots with the HMGR-1 cDNA probe at low stringency, HMGR mRNA was high in June and November, corresponding to periods of high HMGR activity during seedling growth and rapid increase in rubber formation. The seasonal variations in rubber formation and HMGR mRNA, HMGR activity, and rubber transferase activity may be due to low temperature stimulation in the fall and winter months. 相似文献
79.
【目的】葡聚糖酶是饲用添加剂的重要成分,本研究旨在从湖羊消化道微生物中挖掘性质优良的GH9家族葡聚糖酶基因,用于研发新型饲用酶制剂。【方法】从湖羊瘤胃微生物cDNA中扩增IDSGLUC9-25基因,在大肠杆菌中进行异源表达,对重组蛋白进行诱导表达和纯化,研究重组蛋白的酶学性质和底物水解模式。【结果】IDSGLUC9-25基因编码527个氨基酸,包含一个CelD_N结构和一个GH9家族催化结构域;重组蛋白rIDSGLUC9-25分子量约为62.7 kDa,最适反应温度和pH分别为40℃和6.0,在30-50℃下活性较高,在pH 4.0-8.0范围内能够保持较高的稳定性,经pH 4.0-8.0缓冲液处理1 h后残余活性均大于90%;底物谱分析表明,rIDSGLUC9-25能催化大麦β-葡聚糖、苔藓地衣多糖、魔芋胶和木葡聚糖,比活性分别为(443.55±24.48)、(65.56±5.98)、(122.37±2.85)和(159.16±7.73) U/mg;利用薄层色谱法(thin layer chromatography, TLC)和高效液相色谱法(high performance liquid chromatography, HPLC)分析水解产物发现,rIDSGLUC9-25降解大麦葡聚糖主要生成纤维三糖(占总还原糖64.19%±1.19%)和纤维四糖(占总还原糖26.24%±0.12%),催化地衣多糖主要生成纤维三糖(占总还原糖78.46%±0.89%)。【结论】本研究报道了一种来自密螺旋体属细菌的内切β-1,4-葡聚糖酶IDSGLUC9-25 (EC 3.2.1.4),能高效催化多糖底物生成纤维三糖和纤维四糖,为研发饲用酶制剂和制备低聚寡糖建立基础。 相似文献
80.
Jan Tumajer Krešimir Begović Vojtěch Čada Michal Jenicek Jelena Lange Jiří Mašek Ryszard J. Kaczka Miloš Rydval Miroslav Svoboda Lukáš Vlček Václav Treml 《Global Change Biology》2023,29(2):462-476
Radial tree growth is sensitive to environmental conditions, making observed growth increments an important indicator of climate change effects on forest growth. However, unprecedented climate variability could lead to non-stationarity, that is, a decoupling of tree growth responses from climate over time, potentially inducing biases in climate reconstructions and forest growth projections. Little is known about whether and to what extent environmental conditions, species, and model type and resolution affect the occurrence and magnitude of non-stationarity. To systematically assess potential drivers of non-stationarity, we compiled tree-ring width chronologies of two conifer species, Picea abies and Pinus sylvestris, distributed across cold, dry, and mixed climates. We analyzed 147 sites across the Europe including the distribution margins of these species as well as moderate sites. We calibrated four numerical models (linear vs. non-linear, daily vs. monthly resolution) to simulate growth chronologies based on temperature and soil moisture data. Climate–growth models were tested in independent verification periods to quantify their non-stationarity, which was assessed based on bootstrapped transfer function stability tests. The degree of non-stationarity varied between species, site climatic conditions, and models. Chronologies of P. sylvestris showed stronger non-stationarity compared with Picea abies stands with a high degree of stationarity. Sites with mixed climatic signals were most affected by non-stationarity compared with sites sampled at cold and dry species distribution margins. Moreover, linear models with daily resolution exhibited greater non-stationarity compared with monthly-resolved non-linear models. We conclude that non-stationarity in climate–growth responses is a multifactorial phenomenon driven by the interaction of site climatic conditions, tree species, and methodological features of the modeling approach. Given the existence of multiple drivers and the frequent occurrence of non-stationarity, we recommend that temporal non-stationarity rather than stationarity should be considered as the baseline model of climate–growth response for temperate forests. 相似文献