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排序方式: 共有458条查询结果,搜索用时 928 毫秒
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Joost Monen Neil Hattersley Andrew Muroyama Deanna Stevens Karen Oegema Arshad Desai 《PloS one》2015,10(4)
Centromeres are defined epigenetically in the majority of eukaryotes by the presence of chromatin containing the centromeric histone H3 variant CENP-A. Most species have a single gene encoding a centromeric histone variant whereas C. elegans has two: HCP-3 (also known as CeCENP-A) and CPAR-1. Prior RNAi replacement experiments showed that HCP-3 is the functionally dominant isoform, consistent with CPAR-1 not being detectable in embryos. GFP::CPAR-1 is loaded onto meiotic chromosomes in diakinesis and is enriched on bivalents until meiosis I. Here we show that GFP::CPAR-1 signal loss from chromosomes precisely coincides with homolog segregation during anaphase I. This loss of GFP::CPAR-1 signal reflects proteolytic cleavage between GFP and the histone fold of CPAR-1, as CPAR-1::GFP, in which GFP is fused to the C-terminus of CPAR-1, does not exhibit any loss of GFP signal. A focused candidate screen implicated separase, the protease that initiates anaphase by cleaving the kleisin subunit of cohesin, in this cleavage reaction. Examination of the N-terminal tail sequence of CPAR-1 revealed a putative separase cleavage site and mutation of the signature residues in this site eliminated the cleavage reaction, as visualized by retention of GFP::CPAR-1 signal on separating homologous chromosomes at the metaphase-anaphase transition of meiosis I. Neither cleaved nor uncleavable CPAR-1 were centromere-localized in mitosis and instead localized throughout chromatin, indicating that centromere activity has not been retained in CPAR-1. Although the functions of CPAR-1 and of its separase-dependent cleavage remain to be elucidated, this effort reveals a new substrate of separase and provides an in vivo biosensor to monitor separase activity at the onset of meiosis I anaphase. 相似文献
294.
Background
Recent outbreaks of cutaneous leishmaniasis make the disease a public health concern in Punjab, Pakistan. The knowledge of how the population perceives the disease and its vector is essential in order to design an effective management strategy, but such studies are rare in Pakistan.Methodology/Principal Findings
The present study was based on a cross-sectional self-administered survey comprising 250 household samples collected from five localities including Bhawalpur, Multan, Jhang, Faisalabad and Lahore. The results revealed that the respondents had a poor knowledge of the vector and disease. Few of the respondents were aware about the identification of sand flies, their breeding place, biting time, transmission of leishmaniasis and control measures. Skin infection and sandflies as the main disease symptom and vector of the disease, respectively, were known to some of the respondents. Some believed that summer was the main peak incidence of the disease and it could be transmitted from man to man via contact. However, most of the respondents believed that the disease could be cured. Admission to hospitals, cleanliness and use of bed nets were the treatment measures for the disease in suspected patients, whereas some thought that the use of bed nets could be helpful in preventing leishmaniasis infection.Conclusions/Significance
Poor knowledge of the disease and its vector in the study population emphasize the need to initiate health education and awareness campaigns to minimize the risks of cutaneous leishmaniasis outbreaks in the future. 相似文献295.
Taekyung Kim Mark W. Moyle Pablo Lara-Gonzalez Christian De Groot Karen Oegema Arshad Desai 《The Journal of cell biology》2015,209(4):507-517
The conserved Bub1/Bub3 complex is recruited to the kinetochore region of mitotic chromosomes, where it initiates spindle checkpoint signaling and promotes chromosome alignment. Here we show that, in contrast to the expectation for a checkpoint pathway component, the BUB-1/BUB-3 complex promotes timely anaphase onset in Caenorhabditis elegans embryos. This activity of BUB-1/BUB-3 was independent of spindle checkpoint signaling but required kinetochore localization. BUB-1/BUB-3 inhibition equivalently delayed separase activation and other events occurring during mitotic exit. The anaphase promotion function required BUB-1’s kinase domain, but not its kinase activity, and this function was independent of the role of BUB-1/BUB-3 in chromosome alignment. These results reveal an unexpected role for the BUB-1/BUB-3 complex in promoting anaphase onset that is distinct from its well-studied functions in checkpoint signaling and chromosome alignment, and suggest a new mechanism contributing to the coordination of the metaphase-to-anaphase transition. 相似文献
296.
Iram Fozia Iqbal Mohammad S. Khan Irfan U. Rasheed Rashid Khalid Aqsa Khalid Muhammad Aftab Saira Shakoori Abdul R. 《Biological trace element research》2020,193(1):282-293
Biological Trace Element Research - Radioactive gold-198 is a useful diagnostic and therapeutic agent. Gold in the form of nanoparticles possesses even more exciting properties. This work aimed at... 相似文献
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298.
Saif Ahmad Inayat Saleem Fazli Arshad Jamal Mohd Iqbal Malik Zainul Abdin 《Journal of Plant Biology》2007,50(3):351-357
Field experiments were conducted to determine the interactive effect of sulfur (S) and nitrogen (N) applications on seed yield
fromPsoralea corylifolia L. Six treatments were tested: T1 = control (without manure and fertilizers), T2 = manure @ 9 kg plot-1 (10 t ha-1), T3 = S0 N20 Ko P40, T4 = S20 N20 K40 P40, T5 = S20+20 N20 K40 P40, and T6 = S20+20 N20+20 K40P40. Activities of nitrate reductase (NR) and ATP-sulfurylase in the leaves were measured at various phenological stages. These
two enzymes catalyze the rate-limiting steps in the respective assimilatory pathways for nitrate and sulfate. Enzyme activity
was strongly correlated with seed yield, with the greatest performance being achieved with treatment T5. This might be attributed to the optimization of leaf soluble protein and photosynthetic rate, both of which are influenced
by S and N assimilation. 相似文献
299.
Dai C Li D Popovici-Muller J Zhao L Girijavallabhan VM Rosner KE Lavey BJ Rizvi R Shankar BB Wong MK Guo Z Orth P Strickland CO Sun J Niu X Chen S Kozlowski JA Lundell DJ Piwinski JJ Shih NY Siddiqui MA 《Bioorganic & medicinal chemistry letters》2011,21(10):3172-3176
TNF-α converting enzyme (TACE) inhibitors are promising agents to treat inflammatory disorders and cancer. We have investigated novel tartrate diamide TACE inhibitors where the tartrate core binds to zinc in a unique tridentate fashion. Incorporating (R)-2-(2-N-alkylaminothiazol-4-yl)pyrrolidines into the left hand side amide of the tartrate scaffold led to the discovery of potent and selective TACE inhibitors, some of which exhibited good rat oral bioavailability. 相似文献
300.
Carvalho A Olson SK Gutierrez E Zhang K Noble LB Zanin E Desai A Groisman A Oegema K 《PloS one》2011,6(9):e24656
Genetic and genome-wide RNAi approaches available in C. elegans, combined with tools for visualizing subcellular events with high-resolution, have led to increasing adoption of the early C. elegans embryo as a model for mechanistic and functional genomic analysis of cellular processes. However, a limitation of this system has been the impermeability of the embryo eggshell, which has prevented the routine use of small molecule inhibitors. Here, we present a method to permeabilize and immobilize embryos for acute inhibitor treatment in conjunction with live imaging. To identify a means to permeabilize the eggshell, we used a dye uptake assay to screen a set of 310 candidate genes defined by a combination of bioinformatic criteria. This screen identified 20 genes whose inhibition resulted in >75% eggshell permeability, and 3 that permeabilized embryos with minimal deleterious effects on embryo production and early embryonic development. To mount permeabilized embryos for acute drug addition in conjunction with live imaging, we combined optimized inhibition of one of these genes with the use of a microfabricated chamber that we designed. We demonstrate that these two developments enable the temporally controlled introduction of inhibitors for mechanistic studies. This method should also open new avenues of investigation by allowing profiling and specificity-testing of inhibitors through comparison with genome-wide phenotypic datasets. 相似文献