Search

We have developed an innovative method for digestion, preconcentration, and purification of Sb in water samples for Sb isotope analysis. This study provides a useful tool for supporting research aiming to mitigate Sb pollution in aquatic ecosystems.

Peroxisomes are universal eukaryotic organelles essential to plants and animals. Most peroxisomal matrix proteins carry peroxisome targeting signal type 1 (PTS1), a C-terminal tripeptide. Studies from various kingdoms have revealed influences from sequence upstream of the tripeptide on peroxisome targeting, supporting the view that positive charges in the upstream region are the major enhancing elements. However, a systematic approach to better define the upstream elements influencing PTS1 targeting capability is needed. Here, we used protein sequences from 177 plant genomes to perform large-scale and in-depth analysis of the PTS1 domain, which includes the PTS1 tripeptide and upstream sequence elements. We identified and verified 12 low-frequency PTS1 tripeptides and revealed upstream enhancing and inhibiting sequence patterns for peroxisome targeting, which were subsequently validated in vivo. Follow-up analysis revealed that nonpolar and acidic residues have relatively strong enhancing and inhibiting effects, respectively, on peroxisome targeting. However, in contrast to the previous understanding, positive charges alone do not show the anticipated enhancing effect and that both the position and property of the residues within these patterns are important for peroxisome targeting. We further demonstrated that the three residues immediately upstream of the tripeptide are the core influencers, with a 'basic-nonpolar-basic' pattern serving as a strong and universal enhancing pattern for peroxisome targeting. These findings have significantly advanced our knowledge of the PTS1 domain in plants and likely other eukaryotic species as well. The principles and strategies employed in the present study may also be applied to deciphering auxiliary targeting signals for other organelles.

Dissolved gaseous mercury (DGM) and reactive mercury (RHg) are important mercury (Hg) forms in natural water bodies. Knowledge of the concentration levels and isotope compositions of DGM and RHg in aquatic ecosystems is of crucial importance for understanding the fate of Hg and Hg cycle. In this study, we developed a method to preconcentrate the ultratrace levels of DGM and RHg in freshwater for stable isotope analysis. In this method, 10 L of amended water (or after addition of acidic SnCl2) was purged for 2 hours with Hg-free air gas at 4 L min−1, and the Hg(0) product was then collected onto a chlorine-impregnated activated carbon (CLC) trap. This process was repeated for a total of 80 L water for DGM collection or 40 L of water for RHg collection in order to obtain sufficient DGM and RHg amounts for isotope analysis. DGM and RHg collected on CLC traps were then thermally desorbed and further preconcentrated into 40% acid-trapping solutions for stable isotope analysis using cold vapor multicollector-inductively coupled plasma-mass spectrometry (CV-MC-ICPMS). The method was evaluated by laboratory tests using additions of certified Hg(0) and Hg(II) references with known concentrations and isotopic compositions as well as field measurements of duplicate samples. The laboratory tests showed that 98.1 ± 8.1% of DGM (1sd, ranging from 85.1 to 115.9%, n = 14) and 98.7 ± 8.7% of RHg (81.3 to 122%, n = 33) could be extracted from freshwater, and the isotopic compositions of the extracted Hg(0) and Hg(II) agreed well with the injected Hg(0) and Hg(II) references (paired sample T test: p values ≥ 0.20 for all Hg isotope signatures). Based on the results from the laboratory tests, we propose the expanded uncertainty (2sd) of δ202Hg, Δ199Hg, and Δ200Hg to be 0.28‰, 0.07‰, and 0.07‰, respectively, for DGM isotope analysis, and 0.25‰, 0.07‰, and 0.07‰, respectively, for RHg isotope analysis. The duplicate field tests showed negligible differences in DGM and RHg isotopic compositions between the paired samples. These results demonstrate that the extraction method can accurately measure DGM and RHg isotopic compositions in freshwater, providing a useful tool for investigating Hg at ultratrace levels in an aquatic environment.

Red pericarp associates with seed dormancy or preharvest sprouting (PHS) tolerance in crops. To identify this association's molecular mechanism, a PHS mutant Osviviparous1 (Osvp1) was characterized in rice and crossed with Kasalath, a red pericarp cultivar with Rc (red coleoptiles) genotype. Among the dehulled seeds of F2 progenies, RcRcvp1vp1 seeds performed a lower PHS rate than rcrcvp1vp1 seeds and showed shallower pigmentation than RcRcVP1VP1 seeds. Kasalath and SL9 (an RcRcVP1VP1 substitution line with Nipponbare background) showed more ABA sensitivity than the Nipponbare (rcrcVP1VP1) by the germination assay, and the transcriptional abundance of ABA signal genes OsABI2, OsSnRK2, OsVP1, ABI5, and especially OsVP1 increased in the red pericarp line SL9. Moreover, OsVP1 can directly bind Rc (bHLH) promoter by yeast one-hybrid, which activates Rc and OsLAR expression in red pericarp rice. Furthermore, a luciferase complementation imaging assay showed that OsVP1 interacts with transcriptions factors Rc and OsC1. These results indicate that OsVP1 promotes proanthocyanidin accumulation through the interaction among OsVP1, Rc, and OsC1 and then increases the plant's ABA sensitivity and PHS resistance.

Phosphorus (P) deficiency tolerance in rice is a complex character controlled by polygenes. Through proteomics analysis, we could find more low P tolerance related proteins in unique P-deficiency tolerance germplasm Dongxiang wild rice (Oryza Rufipogon, DXWR), which will provide the basis for the research of its regulation mechanism. In this study, a proteomic approach as well as joint analysis with transcriptome data were conducted to identify potential unique low P response genes in DXWR during seedlings. The results showed that 3589 significant differential accumulation proteins were identified between the low P and the normal P treated root samples of DXWR. The degree of change was more than 1.5 times, including 60 up-regulated and 15 downregulated proteins, 24 of which also detected expression changes of more than 1.5-fold in the transcriptome data. Through quantitative trait locus (QTLs) matching analysis, seven genes corresponding to the significantly different expression proteins identified in this study were found to be uncharacterized and distributed in the QTLs interval related to low P tolerance, two of which (LOC_Os12g09620 and LOC_Os03g40670) were detected at both transcriptome and proteome levels. Based on the comprehensive analysis, it was found that DXWR could increase the expression of purple acid phosphatases (PAPs), membrane location of P transporters (PTs), rhizosphere area, and alternative splicing, and it could decrease reactive oxygen species (ROS) activity to deal with low P stress. This study would provide some useful insights in cloning the P-deficiency tolerance genes from wild rice, as well as elucidating the molecular mechanism of low P resistance in DXWR.

Phosphorus (P) deficiency tolerance in rice is a complex character controlled by polygenes. Through proteomics analysis, we could find more low P tolerance related proteins in unique P-deficiency tolerance germplasm Dongxiang wild rice (Oryza Rufipogon, DXWR), which will provide the basis for the research of its regulation mechanism. In this study, a proteomic approach as well as joint analysis with transcriptome data were conducted to identify potential unique low P response genes in DXWR during seedlings. The results showed that 3589 significant differential accumulation proteins were identified between the low P and the normal P treated root samples of DXWR. The degree of change was more than 1.5 times, including 60 up-regulated and 15 downregulated proteins, 24 of which also detected expression changes of more than 1.5-fold in the transcriptome data. Through quantitative trait locus (QTLs) matching analysis, seven genes corresponding to the significantly different expression proteins identified in this study were found to be uncharacterized and distributed in the QTLs interval related to low P tolerance, two of which (LOC_Os12g09620 and LOC_Os03g40670) were detected at both transcriptome and proteome levels. Based on the comprehensive analysis, it was found that DXWR could increase the expression of purple acid phosphatases (PAPs), membrane location of P transporters (PTs), rhizosphere area, and alternative splicing, and it could decrease reactive oxygen species (ROS) activity to deal with low P stress. This study would provide some useful insights in cloning the P-deficiency tolerance genes from wild rice, as well as elucidating the molecular mechanism of low P resistance in DXWR.

Red pericarp associates with seed dormancy or preharvest sprouting (PHS) tolerance in crops. To identify this association's molecular mechanism, a PHS mutant

This work reports a facile synthesis of magnetic hybrids (Fe

Antimony (Sb) isotopes have been shown to be promising tracers for studying Sb cycling in the environment and its impact on ecosystem and human health. Yet precise measurements of Sb isotopic composition have been challenged by low Sb concentrations and high matrix effect and by the lack of a common reference material (zero-delta). Here we report an improved analytical scheme that is capable of high-precision measurement of Sb isotopes in environmental and geochemical samples. The method employs a two-column ion exchange set-up to remove interfering matrix elements to allow Sb isotopic measurements with low Sb (

Zinc-cobalt double-metal sulfides (ZCS) as Faradic electrode materials with high energy density have great potential for supercapacitors, but their poor transfer efficiency for electrons and ions hinders their electrochemical response. Herein, ZnCo2 (CO3 )1.5 (OH)3 @ZCS microflower hybrid arrays consisting of thin nanolayer petals were anchored on three-dimensional graphene (ZnCo2 (CO3 )1.5 (OH)3 @ZCS/3DG) by a simple hydrothermal method and additional ion-exchange process. A ZnCo2 (CO3 )1.5 (OH)3 @ZCS/3DG electrode delivered high capacitance (2228 F g-1 at 1 A g-1 ) and long cycling life (85.7 % retention after 17 000 cycles), which are ascribed to the multicomponent structural design. The 3DG conductive substrate improves the electron-transfer dynamics of the electrode material. Meanwhile, the microflowers consisting of thin nanolayer petals could not only provide many active sites for ions to improve the capacitance, but also alleviate the volume expansion to ensure the structural stability. Furthermore, an all-solid-state asymmetric supercapacitor based on a ZnCo2 (CO3 )1.5 (OH)3 @ZCS/3DG electrode achieved a high energy density of 27 W h kg-1 at 528.3 W kg-1 and exhibits exceptional cyclic stability for 23 000 cycles. Its ability to light a blue LED for 9 min verified the feasibility of its application for energy storage devices.

Previous research has shed light on the detrimental effects of abusive supervision. To extend this area of research, we draw upon conservation of resources theory to propose (a) a causal relationship between abusive supervision and psychological distress, (b) a mediating role of psychological distress on the relationship between abusive supervision and employee silence, and (c) a moderating effect of the supervisor–subordinate relational context (i.e., gender dissimilarity) on the mediating effect of abusive supervision on silence. Through an experimental study (Study 1), we found the causal path linking abusive supervision and psychological distress. Results of both the experimental study and a field study (Study 2) provided evidence that psychological distress mediated the relationship between abusive supervision and silence. Lastly, we found support that this mediation effect was contingent upon the relational context in Study 2 but not in Study 1. We discuss implications for theory and practice.

This work reports a facile synthesis of magnetic hybrids (Fe3O4–Au hybrids) with high SERS activity for detecting a low abundance of cancer cells. We labeled Raman reporter molecule 4-aminothiophenol (4-ATP) and the antibody of CEA (anti-CEA) on Fe3O4–Au hybrid nanoparticles (anti-CEA/4-ATP/Fe3O4–Au) as SERS tags and anti-CEA-labeled Au NPs (anti-CEA/Au) as SERS-active substrates to improve detection sensitivity. In the presence of CEA positive-expressed cancer cells (such as non-small lung cancer cells, A549), sandwich structures were formed as both SERS tags and SERS-active substrates could be bound to CEA at cell surfaces, leading to the formation of SERS hot spots at the junction of SERS tags and SERS-active substrates. As a result, an enhanced SERS signal of 4-ATP arose, which could be used to detect CEA on cell surfaces. This assay can specifically detect CEA-expressed A549 cells at a very low abundance (∼10 cells mL−1) and can be used for evaluating CEA expression levels of different cancer cells line. This assay has the advantages of high sensitivity (because the SERS technique itself enables the detection of very low concentration analytes, even single molecules), high specificity (because of the enhanced SERS signal arising in sandwich configuration, which is formed in specific antigen–antibody interaction events), and high efficiency (because the magnetic SERS tags can concentrate the captured cells and separate them from the complex detection system without repetitive washing steps). These features make our developed assay a rapid and facile method to sensitively detect a low abundance of cancer cells.