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•A colorimetric method for the chiral recognition of tryptophan enantiomers based on β-CD@AgNPs was proposed.•The chiral recognition of D/L-tryptophan was realized according to the ...different binding forces of β-CD and D/L-tryptophan.•The quantitative detection of D/L-tryptophan and the enantiomer percentage of D-Trp in racemates were realized.
Different enantiomer forms of amino acids play different roles in multifarious fields, and improper use will cause irreversible effects. Therefore, the identification of chiral amino acids is a vital issue in the field of pharmaceutical analysis. Herein, a chiral sensing system of β-cyclodextrin coated silver nanoparticle (β-CD@AgNPs) with peroxidase-like activity was designed for the fast and efficient colorimetric identification of tryptophan (Trp) enantiomers based on the difference in binding capacity between D/L-Trp and β-CD. The results showed the satisfactory linearity for detecting D/L-Trp over the concentration range from 0.2 to 4 mM with a LOD of 0.16 and 0.18 mM, respectively. Moreover, the absorbance increased linearly with the rise of D-Trp concentration percentage in the Trp enantiomer mixture. The proposed method avoided the use of natural enzymes and improved the stability due to the protective effect of cyclodextrin, which provided a new idea for selective colorimetric recognition and detection of D/L-Trp based on cyclodextrin.
Mucosal-Associated Invariant T (MAIT) cells are a population of innate T cells that play a critical role in host protection against bacterial and viral pathogens. Upon activation, MAIT cells can ...rapidly respond via both TCR-dependent and -independent mechanisms, resulting in robust cytokine production. The metabolic and nutritional requirements for optimal MAIT cell effector responses are still emerging. Iron is an important micronutrient and is essential for cellular fitness, in particular cellular metabolism. Iron is also critical for many pathogenic microbes, including those that activate MAIT cells. However, iron has not been investigated with respect to MAIT cell metabolic or functional responses. In this study, we show that human MAIT cells require exogenous iron, transported via CD71 for optimal metabolic activity in MAIT cells, including their production of ATP. We demonstrate that restricting iron availability by either chelating environmental iron or blocking CD71 on MAIT cells results in impaired cytokine production and proliferation. These data collectively highlight the importance of a CD71-iron axis for human MAIT cell metabolism and functionality, an axis that may have implications in conditions where iron availability is limited.
Modern change detection (CD) has achieved remarkable success by the powerful discriminative ability of deep convolutions. However, high-resolution remote sensing CD remains challenging due to the ...complexity of objects in the scene. Objects with the same semantic concept may show distinct spectral characteristics at different times and spatial locations. Most recent CD pipelines using pure convolutions are still struggling to relate long-range concepts in space-time. Nonlocal self-attention approaches show promising performance via modeling dense relationships among pixels, yet are computationally inefficient. Here, we propose a bitemporal image transformer (BIT) to efficiently and effectively model contexts within the spatial-temporal domain. Our intuition is that the high-level concepts of the change of interest can be represented by a few visual words, that is, semantic tokens. To achieve this, we express the bitemporal image into a few tokens and use a transformer encoder to model contexts in the compact token-based space-time. The learned context-rich tokens are then fed back to the pixel-space for refining the original features via a transformer decoder. We incorporate BIT in a deep feature differencing-based CD framework. Extensive experiments on three CD datasets demonstrate the effectiveness and efficiency of the proposed method. Notably, our BIT-based model significantly outperforms the purely convolutional baseline using only three times lower computational costs and model parameters. Based on a naive backbone (ResNet18) without sophisticated structures (e.g., feature pyramid network (FPN) and UNet), our model surpasses several state-of-the-art CD methods, including better than four recent attention-based methods in terms of efficiency and accuracy. Our code is available at https://github.com/justchenhao/BIT_CD .
The effects of soil pH variations induced by submergence/drainage and biochar application on soil cadmium (Cd) availability to different rice (Oryza sativa L.) varieties are not well understood. This ...study aims to investigate the possible reasons for available Cd(II) reduction in paddy soil as influenced by biochar and to determine Cd(II) absorption and translocation rates in different parts of various rice varieties. A pot experiment in a greenhouse using four japonica and four indica rice varieties was conducted in Cd(II) contaminated paddy soil with peanut straw biochar. The results indicated that the submerging led to an increase in soil pH due to the consumption of protons (H+) by the reduction reactions of iron/manganese (Fe/Mn) oxides and sulfate (SO42−) and thus the decrease in soil available Cd(II) contents. However, the drainage decreased soil pH due to the release of protons during the oxidation of Fe2+, Mn2+, and S2− and thus the increase in soil available Cd(II) contents. Application of the biochar increased soil pH during soil submerging and inhibited the decline in soil pH during soil drainage, and thus decreased soil available Cd(II) contents under both submerging and drainage conditions. The indica rice varieties absorbed more Cd(II) in their roots and accumulated higher amounts of Cd(II) in their shoots and grains than the japonica rice varieties. The Cd(II) sensitive varieties exhibited a greater absorption and translocation rate of Cd(II) compared to the tolerant varieties of both indica and japonica rice. Biochar inhibited the absorption and accumulation of Cd(II) in the rice varieties, which ultimately lowered the Cd(II) contents in rice grains below the national food safety limit (0.2 mg kg−1). Overall, planting japonica rice varieties in Cd(II) polluted paddy soils combined with the use of biochar can effectively reduce Cd(II) content in rice grains which protects human health against Cd(II) toxicity.
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•Redox reactions were responsible for soil pH change in submergence/drainage alteration.•Biochar inhibited soil pH decline and reduced available soil Cd(II) during drainage.•Indica rice varieties absorbed more Cd(II) from soils than japonica rice varieties.•Cd(II)-sensitive rice varieties absorbed more Cd(II) than tolerant rice varieties.•Biochar decreased Cd(II) contents in the roots, shoots and grains of rice varieties.
Convolutional neural networks (CNNs) have performed notably in change detection (CD) tasks due to their superior learning and automatic feature extraction capabilities. However, they suffer from the ...limited receptive field and the weak modeling of long-range dependencies. Vision transformers excel in modeling long-range context and have been recently introduced in CD. Some works have combined CNN and transformers to obtain local-global information. However, these works do not fully consider the guidance and interactions from both local and global features. Most importantly, most of them involve very large number of parameters and computational costs. To address these issues, in this paper we propose a lightweight CD network that mixes features across CNN and transformer (MixCDNet). We use EfficientNet as backbone and design a novel mixing features block (MFB). First, we employ hierarchical feature extraction blocks, where local-feature blocks (LFBs) and global-feature blocks (GFBs) are utilized for extracting information at different spatial resolution. Second, we propose to exploit bi-directional interactions across LFBs and GFBs branches to provide complementary clues while capturing local and global features. Moreover, a skip-connection and fusion separable self-attention layer (SFSSL) is designed to obtain global features with low complexity. Comprehensive experiments are conducted on three high-resolution remote sensing images CD datasets: LEVIR-CD, WHU-CD and CDD. The results show the effectiveness of the proposed MixCDNet in improving the performance of existing CD methods with fewer parameters (0.32 M) and lower computation cost (1.59 G FLOPs).
Human carcinoembryonic antigen-related cell adhesion molecule 1 (C?/Au: EACAM1) is a cell-surface signaling molecule involved in cell adhesion, proliferation, and immune response. It is also ...implicated in cancer angiogenesis, progression, and metastasis. This diverse set of effects likely arises as a result of the numerous homophilic and heterophilic interactions that CEACAM1 can have with itself and other molecules. Its N-terminal Ig variable (IgV) domain has been suggested to be a principal player in these interactions. Previous crystal structures of the β-sandwich-like IgV domain have been produced using Escherichia coli-expressed material, which lacks native glycosylation. These have led to distinctly different proposals for dimer interfaces, one involving interactions of ABED β-strands and the other involving GFCC′C″ β-strands, with the former burying one prominent glycosylation site. These structures raise questions as to which form may exist in solution and what the effect of glycosylation may have on this form. Here, we use NMR cross-correlation measurements to examine the effect of glycosylation on CEACAM1-IgV dimerization and use residual dipolar coupling (RDC) measurements to characterize the solution structure of the non-glycosylated form. Our findings demonstrate that even addition of a single N-linked GlcNAc at potential glycosylation sites inhibits dimer formation. Surprisingly, RDC data collected on E. coli expressed material in solution indicate that a dimer using the non-glycosylated GFCC′C″ interface is preferred even in the absence of glycosylation. The results open new questions about what other factors may facilitate dimerization of CEACAM1 in vivo, and what roles glycosylation may play in heterophylic interactions.
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•T-Cd0.5Zn0.5S formed by WZ-CZS and ZB-CZS is obtained via a hydrothermal method.•The injection of “hot electrons” generated by the LSPR of Co3(PO4)2 into the T-CZS.•Enhanced activity ...of Co3(PO4)2/T-CZS can be attributed to homo-heterojunction effect.•MPO4 (M = Co, Ba, Bi, Ag, Zn) can enhance the H2 production activity of T-CZS.
Heterojunction photocatalysts have been demonstrated to be effective for the interfacial charge transfer and utilization, if the charge transfer in bulk phase can be promoted, more photoinduced charges can be utilized to achieve a higher efficiency of light energy conversion. Herein, twinned-Cd0.5Zn0.5S (T-CZS) homojunction formed by zinc blende Cd0.5Zn0.5S (ZB-CZS) and wurtzite Cd0.5Zn0.5S (WZ-CZS) is obtained via a facile hydrothermal method, and then Co3(PO4)2 is introduced to the surface of T-CZS to form homo-heterojunction using a solvent evaporation strategy. The photocatalytic H2 evolution tests show that the activity of T-CZS is obviously higher than ZB-CZS or WZ-CZS, and Co3(PO4)2 can increase the H2 releasing rate of T-CZS from 13.0 mmol·h−1·g−1 to 64.8 mmol·h−1·g−1 over 5.7 wt% Co3(PO4)2/T-CZS. The apparent quantum efficiency (AQE) can reach 6.4% under 400 nm light irradiation. Under 800 nm near-infrared light (NIR), the H2 releasing rate can reach 0.23 mmol·h−1·g−1. The investigation shows that the carrier transfer between T-CZS and Co3(PO4)2 follows the S-scheme transfer path according to the electron paramagnetic resonance spectroscopy analysis and calculation by density flooding theory (DFT) The enhanced activity of Co3(PO4)2/T-CZS can be mainly attributed to the homo-heterojunction synergistic effect between ZB-CZS/WZ-CZS homojunction in T-CZS and the S-scheme heterojunction between T-CZS and Co3(PO4)2, which well avoids the rapid recombination of bulk and surface electron-hole pairs by accelerating charge transfer. Meanwhile, the improved light-harvesting ability, more active sites and lower H2 production overpotential induced by Co3(PO4)2, jointly contribute to a quick kinetics of H2 evolution. In addition, other metal phosphates MPO4 (M = Ba, Bi, Ag and Zn) are also employed to enhance the activity of T-CZS, they are all effective candidates for construction homo-heterojunction with T-CZS.
At least five arenaviruses cause viral haemorrhagic fevers in humans. Lassa virus, an Old World arenavirus, uses the cellular receptor -dystroglycan to infect cells. Machupo, Guanarito, Junin and ...Sabia viruses are New World haemorrhagic fever viruses that do not use -dystroglycan. Here we show a specific, high-affinity association between transferrin receptor 1 (TfR1) and the entry glycoprotein (GP) of Machupo virus. Expression of human TfR1, but not human transferrin receptor 2, in hamster cell lines markedly enhanced the infection of viruses pseudotyped with the GP of Machupo, Guanarito and Junin viruses, but not with those of Lassa or lymphocytic choriomeningitis viruses. An anti-TfR1 antibody efficiently inhibited the replication of Machupo, Guanarito, Junin and Sabia viruses, but not that of Lassa virus. Iron depletion of culture medium enhanced, and iron supplementation decreased, the efficiency of infection by Junin and Machupo but not Lassa pseudoviruses. These data indicate that TfR1 is a cellular receptor for New World haemorrhagic fever arenaviruses.
Copper (Cu) and cadmium (Cd) are highly phytotoxic heavy metals that are widespread contaminants in soil. Plants are efficient at taking up heavy metals, which adversely impacts human health. ...Therefore, it is important to decrease the accumulation of Cu/Cd in plants to reduce human exposure from the food web. Here, we determined the function of a rapeseed (Brassica napus) Cu/Cd transporter, plant cadmium resistance protein 2.7 (BnPCR2.7), in enhancing Cu/Cd tolerance in seedlings and decreasing the accumulation of Cu/Cd in seeds. A subcellular localization analysis revealed that BnPCR2.7 is localized at the plasma membrane (PM). CRISPR/Cas9-mediated BnPCR2.7 knockout lines and knockdown lines had increased sensitivity to high Cu/Cd than wild-type (WT) plants. In contrast, overexpression of BnPCR2.7 enhanced the adaptation to high Cu/Cd than in WT. Additionally, the Cu/Cd content in the roots of overexpression lines was significantly lower than those of the WT, while the contents in the stems increased. A non-invasive micro-test technology (NMT) assay showed that overexpression plants promoted the efflux of Cu and Cd from the roots. A field trial of rapeseed grown in soil contaminated with Cu or Cd showed that overexpression plants grew and developed better than the WT with higher yields and less Cu/Cd that accumulated in the seeds, while knockout and knockdown lines were contrary to these results. Additionally, when grown in soils contaminated by both Cu and Cd, the content of these heavy metals decreased by 12–20 % and 20–30 %, respectively, in seeds of overexpression lines. Collectively, BnPCR2.7 may promotes resistance to Cu/Cd by efflux pathways. Significantly, it is a candidate genetic resource to increase the resistance to heavy metals and reduce the accumulation of Cu/Cd in rapeseed.
•BnPCR2.7 was localized to the plasma membrane in rapeseed protoplasts and root cells.•Expression of BnPCR2.7 promoted the tolerance to Cu and Cd toxicity in transgenic yeast and rapeseed.•BnPCR2.7 confers Cu and Cd tolerance by efflux pathways in rapeseed roots.
Compared to other soil remediation technologies, Cd-contaminated farmland soil with low cadmium accumulation (LCA) plant-based safe utilization is more catered to developing countries with food in ...high demand. Hormesis, which describes the fortification of plant growth performance by a low level of environmental stress, can be innovatively used to achieve increases in crop yield and plant functional components, thus amplifying the safe utilization efficiency of low Cd-contaminated soil by LCA plants. In the present study, the growth and physiological responses of Polygonatum sibiricum, a traditional Chinese medicinal herb, were investigated under laboratory conditions of gradient Cd dosage concentrations and times. As a result, the growth performance of P. sibiricum reached the peak of an inverse U-shaped curve of hormesis under e0 mg kg−1 and 9 months of Cd stress, with elevations in tuber biomass (medicinal part), plant height and polysaccharide content (medicinal components) of 143%, 25% and 90%, respectively. Meanwhile, trace Cd accumulation (0.41 mg kg−1) in the tuber guaranteed medicinal edible safety. In addition, Cd-induced hormesis in P. sibiricum was verified to be overcompensated by antioxidation systems. In conclusion, such ‘win-win’ results, including low Cd accumulation and enhancement of plant pharmaceutical value, provided medicinal herbs with a possibility for safe soil utilization.
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•Hormesis offers a new idea for soil Cd control strategy.•Hormesis vitalized P. sibiricum an optimum alternative plant for soil safe utilization.•Cd-induced hormesis in P. sibiricum follows inverse U-shaped curve.•Cd-induced hormesis in P. sibiricum was the overcompensation of antioxidation systems.•Cd content in edible part of P. sibiricum (tuber) guaranteed its edible safety.
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