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41.
本文报导了胰腺提取物中两种可被钙/钙调素依赖性蛋白激酶磷酸化的热稳定蛋白。SDS-PAGE测定其表观分子量分别为17.7kD和6kD。经钙/钙调素依赖性蛋白激酶磷酸化后,其最大磷酸参入量为8.8μmol/g蛋白。同时磷酸化作用导致17.7kD蛋白在SDS-PAGE中迁移率发生变化。本文还进一步分析了各种阳离子对磷酸化的影响,并对此两种蛋白可能具有的生理功能进行了初步探讨。 相似文献
42.
Tetsuo Hashimoto Eiko Otaka Jun Adachi Keiko Mizuta Masami Hasegawa 《Journal of molecular evolution》1993,36(3):282-289
Summary Using - and -hemoglobin sequences, we made a maximum likelihood inference as to the phylogenetic relationship among carnivores, including the two pandas, giant and lesser. Molecular phylogenetic studies up to 1985 had consistently indicated that the giant panda is more closely related to the bear than to the lesser panda. In 1986, however, a contradictory tree was constructed, using hemoglobins and so on, in which the two pandas link together (Tagle et al. 1986). In contrast to that tree, our conclusion supports the close relationship between bear and giant panda. The surface impression of a close relationship between the two pandas drawn from pairwise amino acid differences is explained by a rapid rate of hemoglobin evolution in the bear compared to that in the two pandas.Offprint requests to: T. Hashimoto 相似文献
43.
44.
Axolemma-enriched fractions were isolated from bovine spinal accessory nerves, bovine intradural dorsal roots, and rabbit sciatic nerve by differential centrifugation and separation on a linear 10–40% sucrose (w/w) gradient. The fractions were enriched 4 to 10 fold in acetylcholinesterase, a biochemical marker for axolemma. Axolemma-enriched fractions isolated from uniformly well-myelinated fibers (bovine spinal accessory nerve) contained lower CNPase activity and higher acetylcholinesterase activity than comparable fractions isolated from variably myelinated fibers (rabbit sciatic nerve and bovine intradural roots). Separation by polyacrylamide electrophoresis showed that the molecular weight distribution of all peripheral nerve axolemma-enriched fractions was similar and ranged from 20 to over 150 kilodaltons. All axolemma-enriched fractions appeared to contain a small but variable amount of myelin-specific proteins. Based on biochemical properties, peripheral nerves containing uniformly well-myelinated fibers yield an axolemma-enriched fraction which is least contaminated with myelin-related membranes. 相似文献
45.
Yong Qian Wu Timothy Lawrence Jun Qing Guo Patrick M. Woster 《Bioorganic & medicinal chemistry letters》1993,3(12):2811-2816
A pair of -cyano analogues of decarboxylated S-adenosylmethionine (2a and 2b) were synthesized as potential enzyme activated, irreversible inhibitors of the[pyruvoyl enzyme S-adenosylmethionine decarboxylase (AdoMet-DC). Each of these analogues acts as an irreversible inactivator for ADoMet-DC from Escherichia coli (IC50 values of 9 and 50 μM, respectively). These analogues also inactivate human AdoMet-DC, with KI values of 246.6 and 7.2 μM, and kinact values of 0.29 and 0.03 min−1, respectively. 相似文献
46.
Motivated by investigating the relationship between progesterone and the days in a menstrual cycle in a longitudinal study, we propose a multikink quantile regression model for longitudinal data analysis. It relaxes the linearity condition and assumes different regression forms in different regions of the domain of the threshold covariate. In this paper, we first propose a multikink quantile regression for longitudinal data. Two estimation procedures are proposed to estimate the regression coefficients and the kink points locations: one is a computationally efficient profile estimator under the working independence framework while the other one considers the within-subject correlations by using the unbiased generalized estimation equation approach. The selection consistency of the number of kink points and the asymptotic normality of two proposed estimators are established. Second, we construct a rank score test based on partial subgradients for the existence of the kink effect in longitudinal studies. Both the null distribution and the local alternative distribution of the test statistic have been derived. Simulation studies show that the proposed methods have excellent finite sample performance. In the application to the longitudinal progesterone data, we identify two kink points in the progesterone curves over different quantiles and observe that the progesterone level remains stable before the day of ovulation, then increases quickly in 5 to 6 days after ovulation and then changes to stable again or drops slightly. 相似文献
47.
Chromosomal localization of uroplakin genes of cattle and mice 总被引:2,自引:0,他引:2
Anne M. Ryan James E. Womack Jun Yu Jun-Hsiang Lin Xue-Ru Wu Tung-Tien Sun Virginia Clarke Peter D'Eustachio 《Mammalian genome》1993,4(11):656-661
The asymmetric unit membrane (AUM) of the apical surface of mammalian urinary bladder epithelium contains several major integral membrane proteins, including uroplakins IA and IB (both 27 kDa), II (15 kDa), and III (47 kDa). These proteins are synthesized only in terminally differentiated bladder epithelial cells. They are encoded by separate genes and, except for uroplakins IA and IB, appear to be unrelated in their amino acid sequences. The genes encoding these uroplakins were mapped to chromosomes of cattle through their segregation in a panel of bovine x rodent somatic cell hybrids. Genes for uroplakins IA, IB, and II were mapped to bovine (BTA) Chromosomes (Chrs) 18 (UPK1A), 1 (UPK1B), and 15 (UPK2), respectively. Two bovine genomic DNA sequences reactive with a uroplakin III cDNA probe were identified and mapped to BTA 6 (UPK3A) and 5 (UPK3B). We have also mapped genes for uroplakins 1A and II in mice, to the proximal regions of mouse Chr 7 (Upk1a) and 9 (Upk2), respectively, by analyzing the inheritance of restriction fragment length variants in recombinant inbred mouse strains. These assignments are consistent with linkage relationships known to be conserved between cattle and mice. The mouse genes for uroplakins IB and III were not mapped because the mouse genomic DNA fragments reactive with each probe were invariant among the inbred strains tested. Although the stoichiometry of AUM proteins is nearly constant, the fact that the uroplakin genes are unlinked indicates that their expression must be independently regulated. Our results also suggest likely positions for two human uroplakin genes and should facilitate further analysis of their possible involvement in disease. 相似文献
48.
异育银鲫及其人工杂合种外源遗传物质的检测分析 总被引:22,自引:4,他引:18
采用 DNA 杂交的方法,对异育银鲫及其人工杂合种进行了外源 DNA 的检测分析,发现两个雌核发育系的异育银鲫及其人工杂合种的 DNA 与红鲤 DNA 片段间的分子杂交均有阳性斑点出现,这表明,在异育银鲫及其人工杂合种产生过程中,父本(红鲤)的 DNA 片段的确可以随机地掺入到母本细胞的 DNA 中,从而产生了异精效应,使其子代生长加快,并出现父本性状。 相似文献
49.
细胞核移植技术已被证明是研究发育中核质相互关系的非常重要的手段之一,电融合技术也是近十年发展起来的新型细胞融合技术。本实验运用这两项技术,进行了鼠、兔目间核质杂交实验,小鼠8-细胞核在激活的兔去核卵母细胞中,发生了染色体超前凝聚及核膨胀,融合卵移植到小鼠输卵管4.5天后,冲洗出,有5.4%的重构卵发育到囊胚期,通过染色体检查,囊胚细胞中均为小鼠染色体,其中一个囊胚为正常小鼠核型(2 n=40,XX)。通过本实验,我们认为:鼠兔远缘核质杂交胚胎的早期发育是可能的。 相似文献
50.
Shumin Guo Jie Wu Zhaoqiang Han Zhutao Li Pinshang Xu Shuwei Liu Jinyang Wang Jianwen Zou 《Global Change Biology Bioenergy》2023,15(4):478-493
Existing studies suggest that biochar application can reduce soil nitrous oxide (N2O) emissions, mainly based on short-term results. However, it remains unclear what the effects (i.e., legacy effects) and underlying mechanisms are on N2O emissions after many years of a single application of biochar. Here, we collected intact soil columns from plots without and with biochar application in a subtropical tea plantation 7 years ago for an incubation experiment. We used the N2O isotopocule analysis combined with ammonia oxidizer-specific inhibitors and molecular biology approaches to investigate how the legacy effect of biochar affected soil N2O emissions. Results showed that the soil in the presence of biochar had lower N2O emissions than the control albeit statistically insignificant. The legacy effect of biochar in decreasing N2O emissions may be attributed to the reduced effectiveness of the soil substrate, nitrification and denitrification activities, and the promotion of the further reduction of N2O. The legacy effect of biochar reduced the relative contribution of nitrifier denitrification/bacterial denitrification, nitrification-related N2O production, and the relative abundance of several microorganisms involved in the nitrogen cycle. Our global meta-analysis also showed that the reduction of N2O by biochar increased with increasing application rate but diminished and possibly even reversed with increasing experimental time. In conclusion, our findings suggest that the abatement capacity of biochar on soil N2O emissions may weaken over time after biochar application, but this remains under further investigation. 相似文献