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991.
The expression of theSRS2 gene, which encodes a DNA helicase involved in DNA repair inSaccharomyces cerevisiae, was studied using anSRS2-lacZ fusion integrated at the chromosomalSRS2 locus. It is shown here that this gene is expressed at a low level and is tightly regulated. It is cell-cycle regulated,
with induction probably being coordinated with that of the DNA-synthesis genes, which are transcribed at the G1-S boundary.
It is also induced by DNA-damaging agents, but only during the G2 phase of the cell cycle; this distinguishes it from a number
of other repair genes, which are inducible throughout the cycle. During meiosis, the expression ofSRS2 rises at a time nearly coincident with commitment to recombination. Sincesrs2 null mutants are radiation sensitive essentially when treated in G1, the mitotic regulation pattern described here leads
us to postulate that either secondary regulatory events limit Srs2 activity to G1 cells or Srs2 functions in a repair mechanism
associated with replication. 相似文献
992.
N-terminal Proline-rich Domain Is Required for Scrambling Activity of Human Phospholipid Scramblases
Sarika Rayala Vincent G. Francis Ulaganathan Sivagnanam Sathyanarayana N. Gummadi 《The Journal of biological chemistry》2014,289(19):13206-13218
Human phospholipid scramblase 1 (hPLSCR1), a type II integral class membrane protein, is known to mediate bidirectional scrambling of phospholipids in a Ca2+-dependent manner. hPLSCR2, a homolog of hPLSCR1 that lacks N-terminal proline-rich domain (PRD), did not show scramblase activity. We attribute this absence of scramblase activity of hPLSCR2 to the lack of N-terminal PRD. Hence to investigate the above hypothesis, we added the PRD of hPLSCR1 to hPLSCR2 (PRD-hPLSCR2) and checked whether scramblase activity was restored. Functional assays showed that the addition of PRD to hPLSCR2 restored scrambling activity, and deletion of PRD in hPLSCR1 (ΔPRD-hPLSCR1) resulted in a lack of activity. These results suggest that PRD is crucial for the function of the protein. The effects of the PRD deletion in hPLSCR1 and the addition of PRD to hPLSCR2 were characterized using various spectroscopic techniques. Our results clearly showed that hPLSCR1 and PRD-hPLSCR2 showed Ca2+-dependent aggregation and scrambling activity, whereas hPLSCR2 and ΔPRD-hPLSCR1 did not show aggregation and activity. Thus we conclude that scramblases exhibit Ca2+-dependent scrambling activity by aggregation of protein. Our results provide a possible mechanism for phospholipid scrambling mediated by PLSCRs and the importance of PRD in its function and cellular localization. 相似文献
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David Nderu Francis Kimani Kelvin Thiongo Maureen Akinyi Evaline Karanja Christian G. Meyer Thirumalaisamy P. Velavan 《Parasitology international》2018,67(6):793-799
Rapid diagnostic tests (RDT) are valuable tools that support prudent and timely use of antimalarial drugs, particularly if reliable microscopy is not available. However, the performance and reliability of these tests vary between and within geographical regions. The present study evaluated the performance of routine malaria RDT in Kenyan febrile patients in Busia County, Kenya. A cross sectional study design was employed to recruit febrile patients attending health facilities between August and November 2016. A total of 192 febrile patients who were slide positive and negative were evaluated for their infection status by nested PCR and RDTs (PfHRP2/pLDH). In addition, P. falciparum diversity of the histidine-rich proteins 2 and 3, that influences the RDT test results were determined. All individuals were P. falciparum positive. Among the investigated 192 febrile patients, 76 (40%) were positive by microscopy, 101 (53%) by RDTs and 80 (42%) were PCR positive. The performance of the CareStart? HRP2/pLDH (pf) RDTs was better than microscopy (Sensitivity 94%; Specificity 75%) and Nucleic acid testing (sensitivity 95%, specificity 77%) with high negative predictive values, indicating the suitability of the RDT in routine practice. Specific pfhrp2/pfhrp3 deletions shown to associate with RDT false negativity was not observed. However, high genetic diversity among pfhrp2 gene was observed. Eleven new PfHRP2 and nine PfHRP3 repeats were observed. False positivity by microscopy and under reporting of infections may thus be a barrier in malaria control and elimination programs. The HRP2/pLDH(Pf) based RDT yet demonstrate to be an effective tool for malaria surveillance program. 相似文献
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Jessica St-Pierre Philippe J. Dufresne Alex Carignan Émilie Lévesque Francis Bernard Jean Longtin Louiselle LeBlanc 《Mycopathologia》2018,183(2):399-406
We report the two first cases of human C. gattii meningoencephalitis acquired on the Canadian east coast, from the province of Quebec. Unlike C. neoformans, C. gattii is not known to have an established ecological niche on the North American east coast. C. gattii has recently been responsible for major outbreaks in British Columbia, Canada, and in the American pacific northwest. However, no human cases acquired in other Canadian provinces have been reported to our knowledge. The source of acquisition remains unclear for both patients but since neither had traveled outside of the province of Quebec, we discuss the possibilities of environmental and animal-associated acquisition, as well as the possible established endemicity in new areas. These cases add to the growing reported human and animal cases in areas previously not thought to be endemic for C. gattii. 相似文献
998.
Proteins Identified from Saliva and Salivary Glands of the Chinese Gall Aphid Schlechtendalia chinensis
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Zixiang Yang Lin Ma Frederic Francis Ying Yang Hang Chen Haixia Wu Xiaoming Chen 《Proteomics》2018,18(9)
Aphid saliva plays an essential role in the interaction between aphids and their host plants. Several aphid salivary proteins have been identified but none from galling aphids. Here the salivary proteins from the Chinese gall aphid are analyzed, Schlechtendalia chinensis, via an LC‐MS/MS analysis. A total of 31 proteins are identified directly from saliva collected via an artificial diet, and 141 proteins are identified from extracts derived from dissected salivary glands. Among these identified proteins, 17 are found in both collected saliva and dissected salivary glands. In comparison with salivary proteins from ten other free‐living Hemipterans, the most striking feature of the salivary protein from S. chinensis is the existence of high proportion of proteins with binding activity, including DNA‐, protein‐, ATP‐, and iron‐binding proteins. These proteins maybe involved in gall formation. These results provide a framework for future research to elucidate the molecular basis for gall induction by galling aphids. 相似文献
999.
Review on Challenges and Recent Advances in the Electrochemical Performance of High Capacity Li‐ and Mn‐Rich Cathode Materials for Li‐Ion Batteries
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Prasant Kumar Nayak Evan M. Erickson Florian Schipper Tirupathi Rao Penki Nookala Munichandraiah Philipp Adelhelm Hadar Sclar Francis Amalraj Boris Markovsky Doron Aurbach 《Liver Transplantation》2018,8(8)
Li and Mn‐rich layered oxides, xLi2MnO3·(1–x)LiMO2 (M=Ni, Mn, Co), are promising cathode materials for Li‐ion batteries because of their high specific capacity that can exceed 250 mA h g?1. However, these materials suffer from high 1st cycle irreversible capacity, gradual capacity fading, low rate capability, a substantial charge‐discharge voltage hysteresis, and a large average discharge voltage decay during cycling. The latter detrimental phenomenon is ascribed to irreversible structural transformations upon cycling of these cathodes related to potentials ≥4.5 V required for their charging. Transition metal inactivation along with impedance increase and partial layered‐to‐spinel transformation during cycling are possible reasons for the detrimental voltage fade. Doping of Li, Mn‐rich materials by Na, Mg, Al, Fe, Co, Ru, etc. is useful for stabilizing capacity and mitigating the discharge‐voltage decay of xLi2MnO3·(1–x)LiMO2 electrodes. Surface modifications by thin coatings of Al2O3, V2O5, AlF3, AlPO4, etc. or by gas treatment (for instance, by NH3) can also enhance voltage and capacity stability during cycling. This paper describes the recent literature results and ongoing efforts from our groups to improve the performance of Li, Mn‐rich materials. Focus is also on preparation of cobalt‐free cathodes, which are integrated layered‐spinel materials with high reversible capacity and stable performance. 相似文献
1000.
Dieu-Hien Truong Hoang Chinh Nguyen Julien Bauwens Gabriel Mazzucchelli Georges Lognay Frédéric Francis 《Journal of Plant Interactions》2018,13(1):30-36
The interactions between Arabidopsis thaliana and Plutella xylostella have been considered as a model system to unravel the responses of plants to herbivorous insects. Here, we use a 2-DE proteome approach to detect protein expression changes in the leaves of Arabidopsis plants exposed to P. xylostella larval infestation at 27°C within 8?h. Approximately 450 protein spots were reproducibly detected on gels. Of these, comparing healthy and infested leaves, we identified 18 differentially expressed protein spots. Thirteen proteins were successfully identified by MALDI-TOF/MS and LC-ESI-MS/MS. Functional classification analysis indicated that the differentially identified proteins were associated with amino acid, carbohydrate, energy, lipid metabolism, and photosynthesis. In addition, their relative abundances were assessed according to larval pest feeding on Arabidopsis leaves. These data provide valuable new insights for further works in plant-biotic and environmental stress interaction. 相似文献