Pollution by heavy metals limits the area of land available for cultivation of food crops. A potential solution to this problem might lie in the molecular breeding of food crops for phytoremediation ...that accumulate toxic metals in straw while producing safe and nutritious grains. Here, we identify a rice quantitative trait locus we name cadmium (Cd) accumulation in leaf 1 (CAL1), which encodes a defensin-like protein. CAL1 is expressed preferentially in root exodermis and xylem parenchyma cells. We provide evidence that CAL1 acts by chelating Cd in the cytosol and facilitating Cd secretion to extracellular spaces, hence lowering cytosolic Cd concentration while driving long-distance Cd transport via xylem vessels. CAL1 does not appear to affect Cd accumulation in rice grains or the accumulation of other essential metals, thus providing an efficient molecular tool to breed dual-function rice varieties that produce safe grains while remediating paddy soils.
A pathology‐adaptive nanosystem, in which nest‐like hosts are built based on nanofibers that are transformed from i.v. injected nanoparticles under the acidic tumor microenvironment. The solid tumor ...is artificially modified by nest‐like hosts readily and firmly, resulting in highly efficient accumulation and stabilization of guest theranostics. This strategy shows great potential for the theranostics delivery to tumors.
Cerebral amyloid β-peptide (Aβ) accumulation resulting from an imbalance between Aβ production and clearance is one of the most important causes in the formation of Alzheimer's disease (AD). In order ...to preserve the maintenance of Aβ homeostasis and have a notable AD therapy, achieving a method to clear up Aβ plaques becomes an emerging task. Herein, we describe a self-destructive nanosweeper based on multifunctional peptide-polymers that is capable of capturing and clearing Aβ for the effective treatment of AD. The nanosweeper recognize and bind Aβ via co-assembly through hydrogen bonding interactions. The Aβ-loaded nanosweeper enters cells and upregulates autophagy thus promoting the degradation of Aβ. As a result, the nanosweeper decreases the cytotoxicity of Aβ and rescues memory deficits of AD transgenic mice. We believe that this resourceful and synergistic approach has valuable potential as an AD treatment strategy.
Safe disposal of solid wastes containing heavy metals is a significant task for environment protection. Immobilization treatment is an effective technology to achieve this task. Cementitious material ...treatments and thermal treatments are two types of attractive immobilization treatments due to that the heavy metals could be encapsulated in their dense and durable wasteforms. This paper discusses the heavy metal immobilization mechanisms of these methods in detail. Physical encapsulation and chemical stabilization are two fundamental mechanisms that occur simultaneously during the immobilization processes. After immobilization treatments, the wasteforms build up a low permeable barrier for the contaminations. This reduces the exposed surface of wastes. Chemical stabilization occurs when the heavy metals transform into more stable and less soluble metal bearing phases. The heavy metal bearing phases in the wasteforms are also reviewed in this paper. If the heavy metals are incorporated into more stable and less soluble metal bearing phases, the potential hazards of heavy metals will be lower. Thus, converting heavy metals into more stable phases during immobilization processes should be a common way to enhance the immobilization effect of these immobilization methods.
•The mechanisms of heavy metal immobilization are classified and summarized.•Chemical stabilization: converting heavy metal into less soluble or less toxic form.•Physical encapsulation: encapsulating heavy metals into low permeability wasteforms.•The phase transformation of heavy metal should be the focus of research on mechanism.
Nitrate transporters are primarily responsible for absorption of nitrate from soil and nitrate translocation among different parts of plants. They deliver nitrate to where it is needed. However, ...recent studies have revealed that nitrate transporters are extensively involved in coping with adverse environmental conditions besides limited nitrate/nitrogen availability. In this review, we describe the functions of the nitrate transporters related to abiotic stresses and their regulation. The expected and unexpected roles of nitrate transporters in plant abiotic stress resistance will also be discussed.
A pyropheophorbide‐α‐based building block (Ppa‐PLGVRG‐Van) can be used to construct self‐aggregated superstructures in vivo for highly specific and sensitive diagnosis of bacterial infection by ...noninvasive photoacoustic tomography. This in vivo supramolecular chemistry approach opens a new avenue for efficient, rapid, and early‐stage disease diagnosis with high sensitivity and specificity.
To date, numerous nanosystems have been developed as antibiotic replacements for bacterial infection treatment. However, these advanced systems are limited owing to their nontargeting accumulation ...and the consequent side effects. Herein, transformable polymer–peptide biomaterials have been developed that enable specific accumulation in the infectious site and long‐term retention, resulting in enhanced binding capability and killing efficacy toward bacteria. The polymer–peptide conjugates are composed of a chitosan backbone and two functional peptides, i.e., an antimicrobial peptide and a poly(ethylene glycol)‐tethered enzyme‐cleavable peptide (CPC‐1). The CPC‐1 initially self‐assembles into nanoparticles with pegylated coronas. Upon the peptides are cleaved by the gelatinase secreted by a broad spectrum of bacterial species, the resultant compartments of nanoparticles spontaneously transformed into fibrous nanostructures that are stabilized by enhanced chain–chain interaction, leading to exposure of antimicrobial peptide residues for multivalent cooperative electrostatic interactions with bacterial membranes. Intriguingly, the in situ morphological transformation also critically improves the accumulation and retention of CPC‐1 in infectious sites in vivo, which exhibits highly efficient antibacterial activity. This proof‐of‐concept study demonstrates that pathological environment‐driven smart self‐assemblies may provide a new idea for design of high‐performance biomaterials for disease diagnostics and therapeutics.
Transformable chitosan–peptide biomaterials (CPC‐1) initially self‐assemble into nanoparticles with PEGylated coronas. Upon cleavage of the peptides by gelatinase, the resultant compartments of the nanoparticles spontaneously transform into fibrous nanostructures. The in situ morphological transformation critically improves the accumulation and retention of CPC‐1 in infectious sites in vivo, which exhibits highly efficient antibacterial activity.
Stresses decouple nitrate assimilation and photosynthesis through stress-initiated nitrate allocation to roots (SINAR), which is mediated by the nitrate transporters NRT1.8 and NRT1.5 and functions ...to promote stress tolerance. However, how SINAR communicates with the environment remains unknown. Here, we present biochemical and genetic evidence demonstrating that in Arabidopsis thaliana, ethylene (ET) and jasmonic acid (JA) affect the crosstalk between SINAR and the environment. Electrophoretic mobility shift assays and chromatin immunoprecipitation assays showed that ethylene response factors (ERFs), including OCTADECANOID-RESPONSIVE ARABIDOPSIS AP2/ERF59, bind to the GCC boxes in the NRT1.8 promoter region, while ETHYLENE INSENSITIVE3 (EIN3) binds to the EIN3 binding site motifs in the NRT1.5 promoter. Genetic assays showed that cadmium and sodium stresses initiated ET/JA signaling, which converged at EIN3/EIN3-Like1 (EIL1) to modulate ERF expression and hence to upregulate NRT1.8. By contrast, ET and JA signaling mediated the downregulation of NRT1.5 via EIN3/EIL1 and other, unknown component(s). SINAR enhanced stress tolerance and decreased plant growth under nonstressed conditions through the ET/JA-NRT1.5/NRT1.8 signaling module. Interestingly, when nitrate reductase was impaired, SINAR failed to affect either stress tolerance or plant growth. These data suggest that SINAR responds to environmental conditions through the ET/JA-NRT signaling module, which further modulates stress tolerance and plant growth in a nitrate reductase-dependent manner.
We set out to investigate the interference factors that led to false-positive novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgM detection results using gold immunochromatography ...assay (GICA) and enzyme-linked immunosorbent assay (ELISA) and the corresponding solutions. GICA and ELISA were used to detect SARS-CoV-2 IgM in 86 serum samples, including 5 influenza A virus (Flu A) IgM-positive sera, 5 influenza B virus (Flu B) IgM-positive sera, 5
IgM-positive sera, 5
IgM-positive sera, 6 sera of HIV infection patients, 36 rheumatoid factor IgM (RF-IgM)-positive sera, 5 sera from hypertensive patients, 5 sera from diabetes mellitus patients, and 14 sera from novel coronavirus infection disease 19 (COVID-19) patients. The interference factors causing false-positive reactivity with the two methods were analyzed, and the urea dissociation test was employed to dissociate the SARS-CoV-2 IgM-positive serum using the best dissociation concentration. The two methods detected positive SARS-CoV-2 IgM in 22 mid-to-high-level-RF-IgM-positive sera and 14 sera from COVID-19 patients; the other 50 sera were negative. At a urea dissociation concentration of 6 mol/liter, SARS-CoV-2 IgM results were positive in 1 mid-to-high-level-RF-IgM-positive serum and in 14 COVID-19 patient sera detected using GICA. At a urea dissociation concentration of 4 mol/liter and with affinity index (AI) levels lower than 0.371 set to negative, SARS-CoV-2 IgM results were positive in 3 mid-to-high-level-RF-IgM-positive sera and in 14 COVID-19 patient sera detected using ELISA. The presence of RF-IgM at mid-to-high levels could lead to false-positive reactivity of SARS-CoV-2 IgM detected using GICA and ELISA, and urea dissociation tests would be helpful in reducing SARS-CoV-2 IgM false-positive results.
Typical wide‐band gap cathode interlayer materials are difficulty in reducing interface recombination without limiting charge transport in perovskite solar cells (PSCs). Here, a lead‐doped ...titanium‐oxo cluster protected by S‐containing ligands is introduced at the interface of perovskite and SnO2. By in situ heating, the cluster is transformed into PbSO4‐PbTi3O7 heterostructure. The oxygen atoms from sulfate ion in heterostructure connect with iodine from perovskite to boost interfacial electron extraction and reduce charge recombination. While the yielded metallic interface between PbSO4 and PbTi3O7 promotes the electron transport across the interface. Finally, an efficiency as high as 24.2 % for the modified PSC is obtained. The heterostructure well‐stabilize the interface of perovskite and SnO2, to greatly improve the device stability. This work provides a novel strategy to prepare wide‐band gap cathode interlayer by directional transformation of heterometallic oxo clusters.
A lead‐doped titanium‐oxo cluster protected by sulfur‐containing organic ligands is employed as a molecular model to realize the directional preparation of PbSO4‐PbTi3O7 heterostructure at the cathode interlayer in perovskite solar cells (PSCs). The oxygen atoms from the sulfate ion in the heterostructure connect with iodine from the perovskite to boost interfacial electron extraction and reduce charge recombination. An efficiency as high as 24.2 % for the modified PSC is realized, and the stability of the devices is also improved.
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