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51.
52.
Asymmetric localization is a prerequisite for inscuteable (insc) to function in coordinating and mediating asymmetric cell divisions in Drosophila. We show here that Partner of Inscuteable (Pins), a new component of asymmetric divisions, is required for Inscuteable to asymmetrically localize. In the absence of pins, Inscuteable becomes cytoplasmic and asymmetric divisions of neuroblasts and mitotic domain 9 cells show defects reminiscent of insc mutants. Pins colocalizes with Insc and interacts with the region necessary and sufficient for directing its asymmetric localization. Analyses of pins function in neuroblasts reveal two distinct steps for Insc apical cortical localization: A pins-independent, bazooka-dependent initiation step during delamination (interphase) and a later maintenance step during which Baz, Pins, and Insc localization are interdependent. 相似文献
53.
Evolutionary distances for protein-coding sequences: modeling site- specific residue frequencies 总被引:13,自引:8,他引:5
Estimation of evolutionary distances from coding sequences must take into
account protein-level selection to avoid relative underestimation of longer
evolutionary distances. Current modeling of selection via site-to-site rate
heterogeneity generally neglects another aspect of selection, namely
position-specific amino acid frequencies. These frequencies determine the
maximum dissimilarity expected for highly diverged but functionally and
structurally conserved sequences, and hence are crucial for estimating long
distances. We introduce a codon- level model of coding sequence evolution
in which position-specific amino acid frequencies are free parameters. In
our implementation, these are estimated from an alignment using methods
described previously. We use simulations to demonstrate the importance and
feasibility of modeling such behavior; our model produces linear distance
estimates over a wide range of distances, while several alternative models
underestimate long distances relative to short distances. Site-to-site
differences in rates, as well as synonymous/nonsynonymous and
first/second/third-codon-position differences, arise as a natural
consequence of the site-to-site differences in amino acid frequencies.
相似文献
54.
55.
Cyrenius Jone Laurie Erickson James E. Trosko Chia C. Chang 《Cell biology and toxicology》1987,3(1):1-15
Since chemical modulation of gap junctional intercellular communication has been implicated in several toxicological endpoints, a study to examine the ability of several biological toxins to inhibit this process was undertaken. Eight biological toxins were tested for their ability to inhibit metabolic cooperation, a measure of gap-junctional intercellular communication, in the Chinese V79 cell system. Aplysiatoxin, anhydrodebromoaplysiatoxin and debromoaplysiatoxin showed the strongest ability to inhibit metabolic cooperation while T2-toxin and vomitoxin inhibited metabolic cooperation to a lesser degree. Afatoxin B1, afatoxin B2 and palytoxin were inactive in the Chinese V79 system. Palytoxin, which was extremely cytotoxic, might act as a tumor promoter if it induces compensatory hyperplasia in vivo.Abbreviations 6-TG
6-thioguanine
- TPA
12-0-tetradecanoylphorbol-13-acetate 相似文献
56.
57.
Chia Wei Chang Tye Petrie Alycia Clark Xin Lin Claus S. Sondergaard Leigh G. Griffiths 《PloS one》2016,11(4)
In this study, we investigate the translational potential of a novel combined construct using an FDA-approved decellularized porcine small intestinal submucosa extracellular matrix (SIS-ECM) seeded with human or porcine mesenchymal stem cells (MSCs) for cardiovascular indications. With the emerging success of individual component in various clinical applications, the combination of SIS-ECM with MSCs could provide additional therapeutic potential compared to individual components alone for cardiovascular repair. We tested the in vitro effects of MSC-seeding on SIS-ECM on resultant construct structure/function properties and MSC phenotypes. Additionally, we evaluated the ability of porcine MSCs to modulate recipient graft-specific response towards SIS-ECM in a porcine cardiac patch in vivo model. Specifically, we determined: 1) in vitro loading-capacity of human MSCs on SIS-ECM, 2) effect of cell seeding on SIS-ECM structure, compositions and mechanical properties, 3) effect of SIS-ECM seeding on human MSC phenotypes and differentiation potential, and 4) optimal orientation and dose of porcine MSCs seeded SIS-ECM for an in vivo cardiac application. In this study, histological structure, biochemical compositions and mechanical properties of the FDA-approved SIS-ECM biomaterial were retained following MSCs repopulation in vitro. Similarly, the cellular phenotypes and differentiation potential of MSCs were preserved following seeding on SIS-ECM. In a porcine in vivo patch study, the presence of porcine MSCs on SIS-ECM significantly reduced adaptive T cell response regardless of cell dose and orientation compared to SIS-ECM alone. These findings substantiate the clinical translational potential of combined SIS-ECM seeded with MSCs as a promising therapeutic candidate for cardiac applications. 相似文献
58.
Lai-Ping Wong Rick?Twee-Hee Ong Wan-Ting Poh Xuanyao Liu Peng Chen Ruoying Li Kevin?Koi-Yau Lam Nisha?Esakimuthu Pillai Kar-Seng Sim Haiyan Xu Ngak-Leng Sim Shu-Mei Teo Jia-Nee Foo Linda?Wei-Lin Tan Yenly Lim Seok-Hwee Koo Linda?Seo-Hwee Gan Ching-Yu Cheng Sharon Wee Eric?Peng-Huat Yap Pauline?Crystal Ng Wei-Yen Lim Richie Soong Markus?Rene Wenk Tin Aung Tien-Yin Wong Chiea-Chuen Khor Peter Little Kee-Seng Chia Yik-Ying Teo 《American journal of human genetics》2013,92(1):52-66
Whole-genome sequencing across multiple samples in a population provides an unprecedented opportunity for comprehensively characterizing the polymorphic variants in the population. Although the 1000 Genomes Project (1KGP) has offered brief insights into the value of population-level sequencing, the low coverage has compromised the ability to confidently detect rare and low-frequency variants. In addition, the composition of populations in the 1KGP is not complete, despite the fact that the study design has been extended to more than 2,500 samples from more than 20 population groups. The Malays are one of the Austronesian groups predominantly present in Southeast Asia and Oceania, and the Singapore Sequencing Malay Project (SSMP) aims to perform deep whole-genome sequencing of 100 healthy Malays. By sequencing at a minimum of 30× coverage, we have illustrated the higher sensitivity at detecting low-frequency and rare variants and the ability to investigate the presence of hotspots of functional mutations. Compared to the low-pass sequencing in the 1KGP, the deeper coverage allows more functional variants to be identified for each person. A comparison of the fidelity of genotype imputation of Malays indicated that a population-specific reference panel, such as the SSMP, outperforms a cosmopolitan panel with larger number of individuals for common SNPs. For lower-frequency (<5%) markers, a larger number of individuals might have to be whole-genome sequenced so that the accuracy currently afforded by the 1KGP can be achieved. The SSMP data are expected to be the benchmark for evaluating the value of deep population-level sequencing versus low-pass sequencing, especially in populations that are poorly represented in population-genetics studies. 相似文献
59.
Cymbidium mosaic virus (CyMV) is the most prevalent virus infecting orchids. Here, we report the isolation of partial cDNA clones encoding the genomic RNA of CyMV. Like most of the polyadenylated monopartite positive-strand RNA viruses, the open reading frame (ORF) coding for the viral coat protein (CP) is located at the 3 end. The ORF predicts a polypeptide chain of 220 amino acids with a molecular weight of 23 600. Sequence comparison of this ORF to the CP sequences of potato virus X(PVX) and white clover mosaic virus (WCIMV) revealed a strong amino acid homology in the mid-portion of the CP, but the overall homology was low. The CyMV CP gene was placed downstream of a cauliflower mosaic virus 35S promoter and the chimaeric gene was transferred into Nicotiana benthamiana. Transgenic plants expressing the CyMV CP were protected against CyMV infection. 相似文献
60.
Tringe SG Zhang T Liu X Yu Y Lee WH Yap J Yao F Suan ST Ing SK Haynes M Rohwer F Wei CL Tan P Bristow J Rubin EM Ruan Y 《PloS one》2008,3(4):e1862
The indoor atmosphere is an ecological unit that impacts on public health. To investigate the composition of organisms in this space, we applied culture-independent approaches to microbes harvested from the air of two densely populated urban buildings, from which we analyzed 80 megabases genomic DNA sequence and 6000 16S rDNA clones. The air microbiota is primarily bacteria, including potential opportunistic pathogens commonly isolated from human-inhabited environments such as hospitals, but none of the data contain matches to virulent pathogens or bioterror agents. Comparison of air samples with each other and nearby environments suggested that the indoor air microbes are not random transients from surrounding outdoor environments, but rather originate from indoor niches. Sequence annotation by gene function revealed specific adaptive capabilities enriched in the air environment, including genes potentially involved in resistance to desiccation and oxidative damage. This baseline index of air microbiota will be valuable for improving designs of surveillance for natural or man-made release of virulent pathogens. 相似文献