45 research outputs found
Evaluation of the cytotoxic effects of sodium hypochlorite on human dental stem cells
Purpose: To investigate the influence of sodium hypochlorite (NaOCl) on human dental stem cell proliferation and differentiation.Method: Dental pulp stem cells (DPSCs), periodontal ligament stem cell (PDLSCs), and gingival mesenchymal stem cells (GMSCs) were treated with NaOCl. Cell viability was evaluated with cellular counting kit-8 (CCK8), and cellular adenosine triphosphate (ATP) levels were analyzed by bromodeoxyuridine (BrdU) incorporation and subsequent flow cytometry. Quantitative polymerase chain reaction (qPCR) and western blotting were performed to detect the expressions of differentiation markers.Results: The viability and ATP levels of all three stem cells types were impaired by NaOCl in a concentration- and time-dependent manners. However, the decrease ATP in GMSCs was less than the other two stem cell population (p < 0.05). NaOCl treatment significantly suppressed the proliferation of dental stem cells (p < 0.05). With regard to differentiation marker expression levels, the decrease in Stro-1 was greater in treatment groups when compared to control on Day 7, while increase in levels of dentin sialophosphoprotein (DSPP), bone sialoprotein (BSP), and osteocalcin (OC) was smaller (p < 0.05). The expressional changes of Stro-1, DSPP, BSP, and OC were more prominent in DPSMs and PDLSCs than in GMSCs.Conclusion: NaOCl dose-dependently impairs the viability, proliferation and differentiation of dental stem cells. Thus, its toxicity to dental stem cells needs to be considered in clinical application.Keywords: Dental stem cells, Sodium hypochlorite, Viability, Proliferation, Differentiatio
Arabidopsis IAR4 Modulates Primary Root Growth Under Salt Stress Through ROS-Mediated Modulation of Auxin Distribution
High salinity is one of the major environmental stresses that plants encounter. Roots are the initial and direct organs to perceive the signal. However, how plant roots perceive and respond to salinity at the molecular and physiological levels is still poorly understood. Here, we report that IAA-CONJUGATE-RESISTANT 4 (IAR4) plays a key role in primary root growth under salt stress conditions. Mutation of IAR4 led to increased sensitivity to salt stress conditions, with strongly inhibited primary root growth and reduced survival rate in two iar4 mutant alleles. iar4 mutants accumulated greater Na+ and exhibited a greater Na+/K+ ratio under NaCl treatment. In addition, more reactive oxygen species (ROS) accumulated in the iar4 mutants due to reduced ROS scavenging. NaCl treatment greatly suppressed the expression levels of ProPIN1:PIN1-GFP, ProPIN2:PIN2-GFP, ProPIN3:PIN3-GFP, and ProDR5:GFP, and suppressed root meristem activity in iar4. GSH or auxin treatment greatly recovered the PIN expression, auxin distribution and primary root growth in the iar4 mutants, suggesting ROS is a vital mediator between salt stress and auxin response. Our data support a model in which IAR4 integrates ROS and auxin pathways to modulate primary root growth under salinity stress conditions, by regulation of PIN-mediated auxin transport
Construction of Yeast One-hybrid Bait Reporter Vector for Screening the Binding Proteins of Cassava MeCWINV1
Cellwall invertase (CWIN) hydrolyzes sucrose into glucose and fructose irreversibly, playing key roles in carbohydrate partitioning and plant defence. MeCWINV1 is one of the CWINs in cassava, which contains several light-responsive elements and stress-responsive elements in promoter region. To analyze the regulatory function of MeCWINV1 in the cassava starch accumulation and stress defense response, a 865 bp MeCWINV1 promoter fragment was cloned and inserted into yeast one-hybrid bait vector to construct pCW1-AbAi vector, then was transformed to Y1HGold yeast strains to screen the binding proteins. It might provide a framework for further investigation on the regulation mechanism of MeCWINV1 gene in cassava
Supercritical Fluid CO2 Extraction and Microcapsule Preparation of Lycium barbarum Residue Oil Rich in Zeaxanthin Dipalmitate
The scope of this investigation aimed at obtaining and stabilizing bioactive products derived from Lycium barbarum seeds and peels, which were the byproducts in the processing of fruit juice. Zeaxanthin dipalmitate is a major carotenoid, comprising approximately 80% of the total carotenoid content in the seeds and peels. The method of obtainment was supercritical fluid CO2 extraction, studying different parameters that affect the oil yield and content of zeaxanthin dipalmitate. The optimized protocol to enact successful supercritical fluid CO2 extraction included optimum extraction pressure of 250 bar, temperature at 60 °C over a time span of 2.0 h, and a CO2 flow of 30 g/min, together with the use of a cosolvent (2% ethanol). The yields of oil and zeaxanthin dipalmitate under these optimal conditions were 17 g/100 g and 0.08 g/100 g, respectively. The unsaturated fatty acids were primarily linoleic acid (C18:2), oleic acid (C18:1), and γ-linolenic acid (C18:3), with their contents being as high as 91.85 ± 0.27% of the total fatty acids. The extract was a red-colored oil that was consequently microencapsulated through spray-drying with octenylsuccinate starch, gum arabic, and maltodextrin (13.5:7.5:3, w/w) as wall materials to circumvent lipid disintegration during storage and add to fruit juice in a dissolved form. The mass ratio of core material and wall material was 4:1. These materials exhibited the highest microencapsulation efficiency (92.83 ± 0.13%), with a moisture content of 1.98 ± 0.05% and solubility of 66.22 ± 0.24%. The peroxide content level within the microencapsulated zeaxanthin dipalmitate-rich oil remained at one part per eight in comparison to the unencapsulated oil, following fast-tracked oxidation at 60 °C for 6 weeks. This indicated the potential oxidation stability properties of microcapsule powders. Consequently, this microencapsulated powder has good prospects for development, and can be utilized for a vast spectrum of consumer health and beauty products
Characterization of steroidal saponins in crude extracts from Dioscorea zingiberensis C. H. Wright by ultra-performance liquid chromatography/electrospray ionization quadrupole time-of-flight tandem mass spectrometry
Steroidal saponins are the major bioactive constituents of Dioscorea zingiberensis C H Wright (D zingiberensis) In this work, ultra-performance liquid chromatography/electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC/Q-TOF-MS/MS) was applied to the separation and characterization of steroidal saponins in crude extracts from D zingiberensis. The results showed that fragment ions from glycosidic and cross-ring cleavages gave a wealth of structural information related to aglycone skeletons, sugar types and the sequence of sugar units. According to the summarized fragmentation patterns, identification of steroidal saponins from D zingiberensis could be fulfilled, even when reference standards were unavailable As a result, a total of thirty-one saponins with five aglycone skeletons, including fourteen new trace saponins, were identified or tentatively elucidated in crude extracts from D zingiberensis based on their retention times, the mass spectrometric fragmentation patterns, and MS and MS/MS data (c) 2010 Elsevier B V All rights reserve
Securing Cooperative Spectrum Sensing Against Collusive False Feedback Attack in Cognitive Radio Networks
Distribution of heavy metals and the exploration of potential indicators and hyperaccumulators in Jiang'an River, Chengdu, PR China
As a highly toxic contaminant, heavy metals have been proven to be widely distributed in the water and sediments of the global oceans, rivers, and lakes. Due to the functional differences in urban areas, the extent, characteristics, and hazards of heavy metal pollution in rivers are also different. To monitor and eliminate heavy metal pollution in rivers, indicators and hyperaccumulators perform crucial roles. In this study, heavy metal concentrations in the water, sediment, benthic faunae and aquatic plants of the Jiang'an River (which flows through Chengdu city, Sichuan Province, P.R. China) were investigated, followed by heavy metal correlation analysis of different media to identify potential bioindicator and hyperaccumulator. The results demonstrated that, none of the heavy metals were detected in the water. However, the 6 heavy metals in the surface sediments showed dramatic spatial regional differences, with Ni-As, Ni-Pb, Ni-Cr, Cr-Cu and Cr-Zn being highly significantly correlated. Furthermore, heavy metal contents in surface sediments were highly significantly correlated with the enrichment capacity of Eriocheir sinensis, Polypogon fugax, and Setaria viridis, and significantly correlated with Erigeron acer. Moreover, all plants were poorly enriched with Pb, which may be related to the morphology of Pb in the sediments. Besides, Eriocheir sinensis is a potential indicator of Zn and Cr in the sediments, and Erigeron acer is a possible Zn hyperaccumulator. This research confirms that heavy metals migrated in the water–sediment-benthic-plant system. Therefore, this study can provide a theoretical foundation for river monitoring and administration in Chengdu city and Sichuan Province
THUIR at TREC 2005: Enterprise Track
IR group of Tsinghua University participated in the expert finding task of TREC2005 enterprise track this year. We developed a novel method which is called document reorganization to solve the problem of locating expert for certain query topics. This method collects and combines related information from different media formats to organize a document which describes an expert candidate. This method proves both effective and efficient for expert finding task. Our submitted run (THUENT0505) obtains the best performance in all participants with evaluation metric MAP. The reorganized documents are also significantly smaller in size than the original corpus