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1.
A number of methods of construction of partially balanced incomplete block designs with nested rows and columns are developed and new balanced incomplete block designs with nested rows and columns are obtained as a by-product. 相似文献
2.
Mitsumasa Okamoto Hideo Yamagishi 《International journal of biological macromolecules》1981,3(2):105-113
In a previous study, various intermediates in λ DNA packaging were visualized after lysis of λ-infected cells with osmotic shock and sedimentation through a sucrose formalin cushion onto electron microscope grids. Along this line, a systematic screening for intermediates accumulated in all head mutants available was performed. λA?-infected cells accumulate only empty spherical protein shells (petit λ) bound at an intermediate point along the DNA thread. In situ digestion experiments with restriction endonuclease EcoRI show that the petit λ-DNA complexes are formed at a fixed point on the DNA concatemer. In cells, however, most petit λ was not bound to DNA. In Fec? cells, which are defective in formation of concatemers but normal in head protein synthesis, most petit λ did not sediment onto the carbon film of the grid. In mutant, petit λ, partially full heads and empty heads with released DNA were observed. λFI?-infected cells also accumulate petit λ and partially full heads. The present studies suggest that protein pNu1 is required for complex formation between head precursors and DNA concatemers, for the initiation of DNA packaging, and I for the promotion of DNA packaging, and for stabilization of head structures. The results obtained with other head mutants involved in formation of mature proheads and head completion confirm earlier results obtained by different techniques. 相似文献
3.
From dried leaves of Panax pseudo-ginseng subsp. himalaicus collected in Eastern Himalaya, new dammarane saponins, named pseudo-ginsenosides-F11 and -F8 were isolated along with the known Ginseng-root saponins, ginsenosides-Rb3, Rd and -Re. Pseudo-ginsenoside-F8 was proved to be a mono-acetyl-ginsenoside-Rb3 and the location of its acetyl group was established mainly by 13C NMR spectroscopy. Pseudo-ginsenoside-F11, was identified as the 6-O-α-rhamnopyransyl(1 → 2)-β-glucopyranoside of 3β,6α,12β,25-tetrahydoxy-(20S,24R)-epoxy-dammarane. The C-24 configuration of ocotillone and its related triterpenes was confirmed to be 24R excluding the recent comment by Lavie et al. 相似文献
4.
Myosin light chain kinase binding to plastic 总被引:3,自引:0,他引:3
Methionine-81 and/or -8 of the transmembrane sialoglycoprotein, glycophorin A, have been specifically alkylated with 13CH3I to produce the sulfonium ion derivatives [S-[13C]methylmethionine-8]glycophorin A and [S-[13C]methylmethionine-8 and -81]glycophorin A. 13C NMR spectra of these species show that the resonances of the methyl groups of the modified glycophorins occur at 26.1 ppm downfield from Me4Si. A spin-lattice relaxation time of 0.4 was observed for the 13C-enriched methyl resonances of the sulfonium ion derivatives of Met-8 and -81, which corresponds to an effective correlation time of < 2× 10?10 s. Demethylation of the 2 glycophorin A sulfonium ion species with 2-mercaptoethanol produces native glycophorin A which now has the ε-carbon of the methionine residue(s) 45% isotopically enriched. The ε-carbon of Met-8 was found to occur at 15.7 ppm downfield from Me4Si whereas the ε-carbon of Met-81 exhibited an unusual chemical shift of 2.0 ppm downfield from Me4Si. The spin-lattice relaxation time of both resonances was found to be ~0.3 s. 相似文献
5.
线粒体未折叠蛋白反应(UPR~(mt))作为新发现的细胞内应激机制,直接影响老化、神经退行性疾病、癌症等疾病的发生发展.UPR~(mt)是线粒体为了维持其内部蛋白质的平衡,启动由核DNA编码的线粒体热休克蛋白和蛋白酶等基因群转录活化程序的应激反应.深入探究UPR~(mt)的作用机制对阐明老化和线粒体相关疾病的发病机理具有指导意义.本文主要阐述了线粒体未折叠蛋白反应的诱导因素、线虫和哺乳动物细胞中最新的未折叠蛋白应激反应的信号传导通路、调控因子、具体作用机制以及线粒体未折叠蛋白反应与衰老、免疫等疾病的联系,旨在为这些疾病提供新的理论基础和治疗靶点. 相似文献
6.
过量表达内质网小分子热激蛋白增强番茄的衣霉素抗性 总被引:4,自引:0,他引:4
真核细胞内质网腔内未折叠蛋白的过度积累会引起内质网胁迫(ER胁迫),继而激活未折叠蛋白应答(UPR)信号途径,诱导内质网定位的分子伴侣的大量表达(如BiP和calnexin等)。本工作将CaMV35S启动子驱动的内质网小分子热激蛋白基因(ER-sHSP)导入番茄,发现ER-sHSP的过量表达提高了转基因番茄整株对衣霉素的抗性。衣霉素处理使未转基因番茄中BiP和calnexin基因的表达迅速升高,转基因番茄中这两个基因的表达也有增加,但表达强度明显低于未转基因番茄。说明ER-sHSP能够减轻ER胁迫,并可能参与UPR信号转导途径。 相似文献
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10.
Luigi Montibeller Li Yi Tan Joo Kyung Kim Praveen Paul Jacqueline de Belleroche 《Journal of cellular and molecular medicine》2020,24(11):6055-6069
Amyotrophic lateral sclerosis (ALS) is a disorder that affects motor neurons in motor cortex and spinal cord, and the degeneration of both neuronal populations is a critical feature of the disease. Abnormalities in protein homeostasis (proteostasis) are well established in ALS. However, they have been investigated mostly in spinal cord but less so in motor cortex. Herein, we monitored the unfolded protein (UPR) and heat shock response (HSR), two major proteostasis regulatory pathways, in human post-mortem tissue derived from the motor cortex of sporadic ALS (SALS) and compared them to those occurring in spinal cord. Although the UPR was activated in both tissues, specific expression of select UPR target genes, such as PDIs, was observed in motor cortex of SALS cases strongly correlating with oligodendrocyte markers. Moreover, we found that endoplasmic reticulum-associated degradation (ERAD) and HSR genes, which were activated predominately in spinal cord, correlated with the expression of neuronal markers. Our results indicate that proteostasis is strongly and selectively activated in SALS motor cortex and spinal cord where subsets of these genes are associated with specific cell type. This study expands our understanding of convergent molecular mechanisms occurring in motor cortex and spinal cord and highlights cell type–specific contributions. 相似文献