Multifunctional Antimonene-Silver Nanocomposites for Ultra-Multi-Mode and Multi-Analyte Sensing, Parallel and Batch Logic Computing, Long-Text Information Protection.

To simulate life's emergent functions, mining the multiple sensing capabilities of nanosystems, and digitizing networks of transduction signals and molecular interactions, is an ongoing endeavor. Here, multifunctional antimonene-silver nanocomposites (AM-Ag NCs) are synthesized facilely and fused for molecular sensing and digitization applications (including ultra-multi-mode and multi-analyte sensing, parallel and batch logic computing, long-text information protection). By mixing surfactant, AM, Ag+ and Sodium borohydride (NaBH4) at room temperature for 5 min, the resulting NCs are comprised of Ag nanoparticles scattered within AM nanosheets and protected by the surfactant. Interestingly, AM-Ag NCs exhibit ultra-multi-mode sensing ability for multiplex metal ions (Hg2+, Fe3+, or Al3+), which significantly improved selectivity (≈2 times) and sensitivity (≈400 times) when analyzing the combined channels. Moreover, multiple sensing capabilities of AM-Ag NCs enable diverse batch and parallel molecular logic computations (including advanced cascaded logic circuits). Ultra-multi-mode selective patterns of AM-Ag NCs to 18 kinds of metal ions can be converted into a series of binary strings by setting the thresholds, and realized high-density, long-text information protection for the first time. This study provides new ideas and paradigms for the preparation and multi-purpose application of 2D nanocomposites, but also offers new directions for the fusion of molecular sensing and informatization.

Sequential-Dependent Synthesis of Bimetallic Silver-Chromium Nanoparticles for Multichannel Sensing, Logic Computing, and 3 in 1 Information Protection.

Bimetallic nanomaterials (BNMs) have been used in sensing, biomedicine, and environmental remediation, but their multipurpose and comprehensive applications in molecular logic computing and information security protection have received little attention. Herein, This synthesis method is achieved by sequentially adding reactants under ice bath conditions. Interestingly, Ag-Cr NPs can dynamically selectively sense anions and reductants in multiple channels. Especially, ClO- can be quantitatively detected by oxidizing Ag-Cr NPs with detection limits of 98.37 nM (at 270 nm) and 31.83 nM (at 394 nm). Based on sequential-dependent synthesis process of Ag-Cr NPs, Boolean logic gates and customizable molecular keypad locks are constructed by setting the reactants as the inputs, the states of the resulting solutions as the outputs. Furthermore, dynamically selective response patterns of the Ag-Cr NPs can be converted into binary strings to exploit molecular crypto-steganography to encode, store, and hide information. By integrating the three dimensions of authorization, encryption, and steganography, 3 in 1 advanced information protection based on Ag-Cr nanosensing system can be achieved, which can enhance the anti-cracking ability of information. This research will promote the development and application of nanocomposites in the field of information security and deepen the connection between molecular sensing and the information world.

Adaptive responses of carbon and nitrogen metabolisms to nitrogen-deficiency in Citrus sinensis seedlings.

BACKGROUND: In China, nitrogen (N)-deficiency often occurs in Citrus orchards, which is one of the main causes of yield loss and fruit quality decline. Little information is known about the adaptive responses of Citrus carbon (C) and N metabolisms to N-deficiency. Seedlings of 'Xuegan' (Citrus sinensis (L.) Osbeck) were supplied with nutrient solution at an N concentration of 0 (N-deficiency), 5, 10, 15 or 20 mM for 10 weeks. Thereafter, we examined the effects of N supply on the levels of C and N in roots, stems and leaves, and the levels of organic acids, nonstructural carbohydrates, NH4+-N, NO3--N, total soluble proteins, free amino acids (FAAs) and derivatives (FAADs), and the activities of key enzymes related to N assimilation and organic acid metabolism in roots and leaves. RESULTS: N-deficiency elevated sucrose export from leaves to roots, C and N distributions in roots and C/N ratio in roots, stems and leaves, thus enhancing root dry weight/shoot dry weight ratio and N use efficiency. N-deficient leaves displayed decreased accumulation of starch and total nonstructural carbohydrates (TNC) and increased sucrose/starch ratio as well as a partitioning trend of assimilated C toward to sucrose, but N-deficient roots displayed elevated accumulation of starch and TNC and reduced sucrose/starch ratio as well as a partitioning trend of assimilated C toward to starch. N-deficiency reduced the concentrations of most FAADs and the ratios of total FAADs (TFAADs)/N in leaves and roots. N-deficiency reduced the demand for C skeleton precursors for amino acid biosynthesis, thus lowering TFAADs/C ratio in leaves and roots. N-deficiency increased (decreased) the relative amounts of C-rich (N-rich) FAADs, thus increasing the molar ratio of C/N in TFAADs in leaves and roots. CONCLUSIONS: Our findings corroborated our hypothesis that C and N metabolisms displayed adaptive responses to N-deficiency in C. sinensis seedlings, and that some differences existed between roots and leaves in N-deficiency-induced alterations of and C and N metabolisms.

Microbial Lipopeptide Supramolecular Self-Assemblies as a Methuosis-Like Cell Death Inducer with In Vivo Antitumor Activity.

Discovering new drugs and improving action mechanisms is a promising strategy to overcome chemotherapy ineffectiveness caused by cancer cell apoptosis resistance. Natural products (like cyclic lipopeptides, CLPs) are potential sources of nonapoptotic cell death inducers and can form diverse supramolecular structures, closely relating to their bioactivities. Herein, it is found for the first time that fatty chain is the key to maintain self-assembled form and antitumor activity of microbial-derived amphiphilic CLP bacillomycin Lb (B-Lb). Compared with B-Lb analogues assemblies without antitumor activity, B-Lb supramolecular self-assemblies (including nanomicelles, nanofibers, giant micrometer rods) can be generated in a multilevel and cross-scale manner and served as a methuosis-like cell death inducer triggered by cytoplasmic vacuolation through macropinocytosis in MDA-MB-231-Luc and MCF-7 cells and in vivo tumor-bearing mice. This study will promote constructing of customized CLP micro-/nanostructures with multipurposes and functions, and boost designing of new antitumor drugs as nonapoptotic cell death modulators based on structure-activity relationship.

Boron-mediated amelioration of copper-toxicity in sweet orange [Citrus sinensis (L.) Osbeck cv. Xuegan] seedlings involved reduced damage to roots and improved nutrition and water status.

'Xuegan' (Citrus sinensis) seedlings were fertilized 6 times weekly for 24 weeks with 0.5 or 350 µM CuCl2 and 2.5, 10 or 25 µM H3BO3. Cu-toxicity increased Cu uptake per plant (UPP) and Cu concentrations in leaves, stems and roots, decreased water uptake and phosphorus, nitrogen, calcium, magnesium, potassium, sulfur, boron and iron UPP, and increased the ratios of magnesium, potassium, calcium and sulfur UPP to phosphorus UPP and the ratios of leaf magnesium, potassium and calcium concentrations to leaf phosphorus concentration. Many decaying and dead fibrous roots occurred in Cu-toxic seedlings. Cu-toxicity-induced alterations of these parameters and root damage decreased with the increase of boron supply. These results demonstrated that B supplementation lowered Cu uptake and its concentrations in leaves, stems and roots and subsequently alleviated Cu-toxicity-induced damage to root growth and function, thus improving plant nutrient (decreased Cu uptake and efficient maintenance of the other nutrient homeostasis and balance) and water status. Further analysis indicated that the improved nutrition and water status contributed to the boron-mediated amelioration of Cu-toxicity-induced inhibition of seedlings, decline of leaf pigments, large reduction of leaf CO2 assimilation and impairment of leaf photosynthetic electron transport chain revealed by greatly altered chlorophyll a fluorescence (OJIP) transients, reduced maximum quantum yield of primary photochemistry (Fv/Fm), quantum yield for electron transport (ETo/ABS) and total performance index (PIabs,total), and elevated dissipated energy per reaction center (DIo/RC). To conclude, our findings corroborate the hypothesis that B-mediated amelioration of Cu-toxicity involved reduced damage to roots and improved nutrient and water status. Principal component analysis showed that Cu-toxicity-induced changes of above physiological parameters generally decreased with the increase of B supply and that B supply-induced alterations of above physiological parameters was greater in 350 µM Cu-treated than in 0.5 µM Cu-treated seedlings. B and Cu had a significant interactive influence on C. sinensis seedlings.

Multifunctional Carbon Nanocomposites as Nanoneurons from Multimode and Multianalyte Sensing to Molecular Logic Computing, Steganography, and Cryptography.

Inspired by information exchange and logic functions of life based on molecular recognition and interaction networks, ongoing efforts are directed toward development of molecular or nanosystems for multiplexed chem/biosensing and advanced information processing. However, because of their preparation shortcomings, poor functionality, and limited paradigms, it is still a big challenge to develop advanced nanomaterials-based systems and comprehensively realize neuron-like functions from multimode sensing to molecular information processing and safety. Herein, using fish scales derived carbon nanoparticles (FSCN) as a reducing agent and stabilizer, a simple one-step synthesis method of multifunctional silver-carbon nanocomposites (AgNPs-FSCN) is developed. The prepared AgNPs-FSCN own wide antibacterial and multisignal response abilities in five channels (including color, Tyndall, absorption and fluorescence intensities, and absorption wavelength) for quantitative colorimetric and fluorescence sensing of H2 O2 , ascorbic acid, and dopamine. Benefiting from its multicoding stimuli-responsive ability, molecular concealment, and programmability, AgNPs-FSCN can be abstracted as nanoneurons for implementing batch and parallel molecular logic computing, steganography, and cryptography. This research will promote the preparation of advanced multifunctional nanocomposites and the development of their multipurpose applications, including the multireadout-guided multianalyte intelligent sensing and sophisticated molecular computing, communication, and security.

Peptide-based system for sensing Pb2+ and molecular logic computing.

Peptides with recognition, assembly, various activities exhibit strong power and application prospects in sensing, material science, biomedicine. However, peptide-based sensing and expanding application is still at an early stage. Herein, a peptide-based sensing and logic system was developed for highly sensitive and selective detection of Pb2+ and implementation of logic operations. Our Pb2+ assay method was ultra-rapid (less than 1 min), direct, simple with detection limit of 0.75 nM. Flexibility and scalability of peptide-based solution system facilitated the execution of sensing and logic operations from simple to complex. This research will not only inspire discovery and comprehensive applications (such as sensing and assembly) of more functional peptides, but also provide more opportunities for development and design of peptide-based systems and molecular information technologies.

In Vivo Imaging of Hypoxia Associated with Inflammatory Bowel Disease by a Cytoplasmic Protein-Powered Fluorescence Cascade Amplifier.

Accurate and sensitive imaging of hypoxia associated with inflammatory bowel disease (IBD) is significant for the precise diagnosis and treatment of this disease, but it remains a challenge for traditional hypoxia-activatable fluorescence probes because of a more moderate hypoxic state during IBD than under other pathological conditions. To address this issue, herein, we designed a hypoxia-activatable and cytoplasmic protein-powered fluorescence cascade amplifier, named HCFA, to image hypoxia associated with IBD in vivo. In our design, a 4-aminobenzoic acid (azo)-modified mesoporous silica nanoparticle (MSN) was used as a container to load black hole quencher 2 (BHQ2) and cytoplasmic protein-binding squarylium dye (SQ); then, the ß-cyclodextrin polymer (ß-CDP) combined with azo through a host-guest interaction to form HCFA. Upon passive stagnation in the inflamed tissue of IBD, the azo band would be cleaved under a hypoxic microenvironment, and SQ was released to activate the fluorescence of HCFA. Moreover, the unconstrained SQ can bind with cytoplasmic protein to exhibit drastic fluorescence intensity enhancement, realizing the fluorescence signal amplification for imaging of hypoxia. When one takes advantage of the large load capacity of MSN and the unique property of SQ, HCFA can sense oxygen levels in the range of 0% to 10%. Meanwhile, the fluorescence imaging results demonstrate that HCFA can sensitively distinguish different levels of cellular hypoxia and monitor the variations of hypoxia in vivo, highlighting HCFA as a promising tool for the detection of hypoxia associated with IBD.

Matter, energy and information network of a graphene-peptide-based fluorescent sensing system for molecular logic computing, detection and imaging of cancer stem cell marker CD133 in cells and tumor tissues.

Tumorigenesis, metastasis, and the recurrence of cancer, which may result from the abnormal presence or activation of cancer stem cells (CSCs), are involved in disorders of exchanged matter (biomarkers), energy and information in living organisms. Rapid and sensitive detection and imaging of CSC biomarkers (such as CD133) are helpful for early diagnosis and therapeutic evaluation of tumors. Recently, a preliminary exploration of a few affinity molecules (like peptide-based probes) has just begun for chemical measurements and imaging of CSC biomarker CD133. However, a comprehensive analysis of the matter, energy and information in an artificial molecular system has not been demonstrated and applied to biosensing and disease diagnosis. In this study, a graphene-peptide-based fluorescent sensing system was constructed by utilizing a graphene oxide platform and a CD133-specific recognition peptide and comprehensively analysed with respect to matter (molecular events), energy (fluorescence) and information flow. The molecular event interaction networks in this system were further used to perform molecular logic computing, for the sensitive detection of CSC marker CD133 (with a linear range from 0 to 630 nM and a detection limit of 7.91 nM), and for an application involving targeting the imaging of cells and tumor tissues that highly express CD133 (with a detection limit of 1.1 × 103 cells per mL for CT26 CSCs). The present report will provide more opportunities for the development and design of molecular-level intelligent complex systems and will probably promote the development of artificial intelligent sensing and treatment systems, a molecular-level "Internet of Things", and artificial life.

A comprehensive genomic and growth proteomic analysis of antitumor lipopeptide bacillomycin Lb biosynthesis in Bacillus amyloliquefaciens X030.

Lipopeptides (such as iturin, fengycin, and surfactin) from Bacillus possess antibacterial, antifungal, and antiviral activities and have important application in agriculture and pharmaceuticals. Although unremitting efforts have been devoted to improve lipopeptide production by designing gene regulatory circuits or optimizing fermentation process, little attention has been paid to utilizing multi-omics for systematically mining core genes and proteins during the bacterial growth cycle. Here, lipopeptide bacillomycin Lb from new Bacillus amyloliquefaciens X030 was isolated and first found to have anticancer activity in various cancer cells (such as SMMC-7721 and MDA-MB-231). A comprehensive genomic and growth proteomic analysis of X030 revealed bacillomycin Lb biosynthetic gene cluster, key enzymes and potential regulatory proteins (PerR, PhoP, CcpA, and CsfB), and novel links between primary metabolism and bacillomycin Lb production in X030. The antitumor activity of the fermentation supernatant supplemented with amino acids (such as glutamic acid) and sucrose was significantly increased, verifying the role of key metabolic switches in the metabolic regulatory network. Quantitative real-time PCR analysis confirmed that 7 differential expressed genes exhibited a positive correlation between changes at transcriptional and translational levels. The study not only will stimulate the deeper and wider antitumor study of lipopeptides but also provide a comprehensive database, which promotes an in-depth analysis of pathways and networks for complex events in lipopeptide biosynthesis and regulation and gives great help in improving the yield of bacillomycin Lb (media optimization, genetic modification, or pathway engineering).

The Boolean logic tree of molecular self-assembly system based on cobalt oxyhydroxide nanoflakes for three-state logic computation, sensing and imaging of pyrophosphate in living cells and in vivo.

Sensing of pyrophosphate (PPi) is helpful to better understand many life processes and diagnose various early-stage diseases. However, many traditional reported methods based on artificial receptors for sensing of PPi exhibit some disadvantages including difficulties in designing appropriate binding sites and complicated multi-step assembly/functionalization. Thus, it is significantly important and a big challenge to know how to use a simple molecular self-assembly or an interaction system to solve the above-mentioned limits to achieve the quantitative analysis of specific substances in the system. Based on the natural connection and similarity (such as stimulus responsiveness) between sensing and logic computing, in this study, the Boolean logic tree of molecular self-assembly system based on the cobalt oxyhydroxide (CoOOH) nanoplatform is constructed and applied to organize and connect "plug and play" molecular events (fluorescent dye, acridine orange and anion, PPi). By using molecules as inputs and the corresponding fluorescence signal as the output, the CoOOH-based molecular self-assembly system can be programmed for three-input fluorescent Boolean logic computation, fluorescent three-state logic computation, detection of PPi (linear range from 50 to 6400 nM with a detection limit of 20 nM) and even for imaging in living cancer cells and in vivo (in systems such as Zebrafish and Carassius auratus). Our approach adds a new dimension for expanding molecular logic computing and sensing systems, which will not only provide more opportunities for developing novel logic computing paradigms, but also be helpful in promoting the development and applications of intelligent molecular computing and sensing systems.

Directly repurposing waste optical discs with prefabricated nanogrooves as a platform for investigation of cell-substrate interactions and guiding neuronal growth.

Due to rapid change in information technology, many consumer electronics become electronic waste which is the fastest-growing pollution problems worldwide. In fact, many discarded electronics with prefabricated micro/nanostructures may provide a good basis to fulfill special needs of other fields, such as tissue engineering, biosensors, and energy. Herein, to take waste optical discs as an example, we demonstrate that discarded electronics can be directly repurposed as highly anisotropic platforms for in vitro investigation of cell behaviors, such as cell adhesion, cell alignment, and cell-cell interactions. The PC12 cells cultured on biocompatible DVD polycarbonate layers with flat and grooved morphology show a distinct cell morphology, indicating the topographical cue of nanogrooves plays a key role in guidance of neurites growth. By further monitoring cell morphology and alignment of PC12 cells cultured on the DVD nanogrooves at different differentiation times, we find that cell contact interaction with nanotopographies is dynamically adjustable with differentiation time from initial disorder to final order. This study adds a new dimension to not only solving the problems of supply of materials and fabrication of nanopatterns in neural tissue engineering, but may also offering a new promising way of waste minimization or reuse for environmental protection.

Boolean Logic Tree of Label-Free Dual-Signal Electrochemical Aptasensor System for Biosensing, Three-State Logic Computation, and Keypad Lock Security Operation.

The most serious and yet unsolved problems of molecular logic computing consist in how to connect molecular events in complex systems into a usable device with specific functions and how to selectively control branchy logic processes from the cascading logic systems. This report demonstrates that a Boolean logic tree is utilized to organize and connect "plug and play" chemical events DNA, nanomaterials, organic dye, biomolecule, and denaturant for developing the dual-signal electrochemical evolution aptasensor system with good resettability for amplification detection of thrombin, controllable and selectable three-state logic computation, and keypad lock security operation. The aptasensor system combines the merits of DNA-functionalized nanoamplification architecture and simple dual-signal electroactive dye brilliant cresyl blue for sensitive and selective detection of thrombin with a wide linear response range of 0.02-100 nM and a detection limit of 1.92 pM. By using these aforementioned chemical events as inputs and the differential pulse voltammetry current changes at different voltages as dual outputs, a resettable three-input biomolecular keypad lock based on sequential logic is established. Moreover, the first example of controllable and selectable three-state molecular logic computation with active-high and active-low logic functions can be implemented and allows the output ports to assume a high impediment or nothing (Z) state in addition to the 0 and 1 logic levels, effectively controlling subsequent branchy logic computation processes. Our approach is helpful in developing the advanced controllable and selectable logic computing and sensing system in large-scale integration circuits for application in biomedical engineering, intelligent sensing, and control.

Boolean logic tree of graphene-based chemical system for molecular computation and intelligent molecular search query.

The most serious, and yet unsolved, problem of constructing molecular computing devices consists in connecting all of these molecular events into a usable device. This report demonstrates the use of Boolean logic tree for analyzing the chemical event network based on graphene, organic dye, thrombin aptamer, and Fenton reaction, organizing and connecting these basic chemical events. And this chemical event network can be utilized to implement fluorescent combinatorial logic (including basic logic gates and complex integrated logic circuits) and fuzzy logic computing. On the basis of the Boolean logic tree analysis and logic computing, these basic chemical events can be considered as programmable "words" and chemical interactions as "syntax" logic rules to construct molecular search engine for performing intelligent molecular search query. Our approach is helpful in developing the advanced logic program based on molecules for application in biosensing, nanotechnology, and drug delivery.

Boron Reduced Copper Excess-Induced Oxidative Damage in Citrus sinensis by Modulating Reactive Oxygen Species and Methylglyoxal Formation and Their Detoxification Systems.

Citrus is mainly cultivated in acid soil with low boron (B) and high copper (Cu). In this study, Citrus sinensis seedlings were submitted to 0.5 (control) or 350 µM Cu (Cu excess or Cu exposure) and 2.5, 10, or 25 µM B for 24 weeks. Thereafter, H2O2 production rate (HPR), superoxide production rate (SAPR), malondialdehyde, methylglyoxal, and reactive oxygen species (ROS) and methylglyoxal detoxification systems were measured in leaves and roots in order to test the hypothesis that B addition mitigated Cu excess-induced oxidative damage in leaves and roots by reducing the Cu excess-induced formation and accumulation of ROS and MG and by counteracting the impairments of Cu excess on ROS and methylglyoxal detoxification systems. Cu and B treatments displayed an interactive influence on ROS and methylglyoxal formation and their detoxification systems. Cu excess increased the HPR, SAPR, methylglyoxal level, and malondialdehyde level by 10.9% (54.3%), 38.9% (31.4%), 50.3% (24.9%), and 312.4% (585.4%), respectively, in leaves (roots) of 2.5 µM B-treated seedlings, while it only increased the malondialdehyde level by 48.5% (97.8%) in leaves (roots) of 25 µM B-treated seedlings. Additionally, B addition counteracted the impairments of Cu excess on antioxidant enzymes, ascorbate-glutathione cycle, sulfur metabolism-related enzymes, sulfur-containing compounds, and methylglyoxal detoxification system, thereby protecting the leaves and roots of Cu-exposed seedlings against oxidative damage via the coordinated actions of ROS and methylglyoxal removal systems. Our findings corroborated the hypothesis that B addition alleviated Cu excess-induced oxidative damage in leaves and roots by decreasing the Cu excess-induced formation and accumulation of ROS and MG and by lessening the impairments of Cu excess on their detoxification systems. Further analysis indicated that the pathways involved in the B-induced amelioration of oxidative stress caused by Cu excess differed between leaves and roots.

Multimorphological Remoldable Silver Nanomaterials from Multimode and Multianalyte Colorimetric Sensing to Molecular Information Technology.

Inspired by life's interaction networks, ongoing efforts are to increase complexity and responsiveness of multicomponent interactions in the system for sensing, programmable control, or information processing. Although exquisite preparation of single uniform-morphology nanomaterials has been extremely explored, the potential value of facile and one-pot preparation of multimorphology nanomaterials has been seriously ignored. Here, multimorphological silver nanomaterials (M-AgN) prepared by one pot can form interaction networks with various analytes, which can be successfully realized from multimode and multianalyte colorimetric sensing to molecular information technology (logic computing and security). The interaction of M-AgN with multianalytes not only induces multisignal responses (including color, absorbance, and wavelength shift) for sensing metal ions (Cr3+, Hg2+, and Ni2+) but also can controllably reshape its four morphologies (nanodots, nanoparticles, nanorods, and nanotriangles). By abstracting binary relationships between analytes and response signals, multicoding parallel logic operations (including simple logic gates and cascaded circuits) can be performed. In addition, taking advantage of natural concealment and molecular response characteristics of M-AgN nanosystems can also realize molecular information encoding, encryption, and hiding. This research not only promotes the construction and application of multinano interaction systems based on multimorphology and multicomponent nanoset but also provides a new imagination for the integration of sensing, logic, and informatization.

An Integrated Analysis of Metabolome, Transcriptome, and Physiology Revealed the Molecular and Physiological Response of Citrus sinensis Roots to Prolonged Nitrogen Deficiency.

Citrus sinensis seedlings were supplied with a nutrient solution containing 15 (control) or 0 (nitrogen (N) deficiency) mM N for 10 weeks. Extensive metabolic and gene reprogramming occurred in 0 mM N-treated roots (RN0) to cope with N deficiency, including: (a) enhancing the ability to keep phosphate homeostasis by elevating the abundances of metabolites containing phosphorus and the compartmentation of phosphate in plastids, and/or downregulating low-phosphate-inducible genes; (b) improving the ability to keep N homeostasis by lowering the levels of metabolites containing N but not phosphorus, upregulating N compound degradation, the root/shoot ratio, and the expression of genes involved in N uptake, and resulting in transitions from N-rich alkaloids to carbon (C)-rich phenylpropanoids and phenolic compounds (excluding indole alkaloids) and from N-rich amino acids to C-rich carbohydrates and organic acids; (c) upregulating the ability to maintain energy homeostasis by increasing energy production (tricarboxylic acid cycle, glycolysis/gluconeogenesis, oxidative phosphorylation, and ATP biosynthetic process) and decreasing energy utilization for amino acid and protein biosynthesis and new root building; (d) elevating the transmembrane transport of metabolites, thus enhancing the remobilization and recycling of useful compounds; and (e) activating protein processing in the endoplasmic reticulum. RN0 had a higher ability to detoxify reactive oxygen species and aldehydes, thus protecting RN0 against oxidative injury and delaying root senescence.

Roles of Hormones in Elevated pH-Mediated Mitigation of Copper Toxicity in Citrus sinensis Revealed by Targeted Metabolome.

The effects of copper (Cu)-pH interactions on the levels of hormones and related metabolites (HRMs) in Citrus sinensis leaves and roots were investigated. Our findings indicated that increased pH mitigated Cu toxicity-induced alterations of HRMs, and Cu toxicity increased low-pH-induced alterations of HRMs. Increased pH-mediated decreases in ABA, jasmonates, gibberellins, and cytokinins, increases in (±)strigol and 1-aminocyclopropanecarboxylic acid, and efficient maintenance of salicylates and auxins homeostasis in 300 µM Cu-treated roots (RCu300); as well as efficient maintenance of hormone homeostasis in 300 µM Cu-treated leaves (LCu300) might contribute to improved leaf and root growth. The upregulation of auxins (IAA), cytokinins, gibberellins, ABA, and salicylates in pH 3.0 + 300 µM Cu-treated leaves (P3CL) vs. pH 3.0 + 0.5 µM Cu-treated leaves (P3L) and pH 3.0 + 300 µM Cu-treated roots (P3CR) vs. pH 3.0 + 0.5 µM Cu-treated roots (P3R) might be an adaptive response to Cu toxicity, so as to cope with the increased need for reactive oxygen species and Cu detoxification in LCu300 and RCu300. Increased accumulation of stress-related hormones (jasmonates and ABA) in P3CL vs. P3L and P3CR vs. P3R might reduce photosynthesis and accumulation of dry matter, and trigger leaf and root senescence, thereby inhibiting their growth.

CTAB-capped Mn-doped ZnS quantum dots and label-free aptamer for room-temperature phosphorescence detection of mercury ions.

A new room-temperature phosphorescence (RTP) mercury ions sensor has been developed based on cetyltrimethylammonium bromide-capped Mn-doped ZnS quantum dots (CTAB/Mn-ZnS QDs) and label-free thymine (T)-rich aptamer. The formed T-Hg(2+)-T dsDNA can linearly quench the RTP of Mn-ZnS QDs through electron transfer and aggregation effect, and give a detection limit of 1.5 nM.

Highly sensitive, selective, and rapid fluorescence Hg2+ sensor based on DNA duplexes of poly(dT) and graphene oxide.

Coupling T base with Hg(2+) to form stable T-Hg(2+)-T complexes represents a new direction in detection of Hg(2+). Here a graphene oxide (GO)-based fluorescence Hg(2+) analysis using DNA duplexes of poly(dT) that allows rapid, sensitive, and selective detection is first reported. The Hg(2+)-induced T(15)-(Hg(2+))(n)-T(15) duplexes make T(15) unable to hybridize with its complementary A(15) labelled with 6'-carboxyfluorescein (FAM-A(15)), which has low fluorescence in the presence of GO. On the contrary, when T(15) hybridizes with FAM-A(15) to form double-stranded DNA because of the absence of Hg(2+), the fluorescence largely remains in the presence of GO. A linear range from 10 nM to 2.0 µM (R(2) = 0.9963) and a detection limit of 0.5 nM for Hg(2+) were obtained under optimal experimental conditions. Other metal ions, such as Al(3+), Ag(+), Ca(2+), Ba(2+), Mg(2+), Zn(2+), Mn(2+), Co(2+), Pb(2+), Ni(2+), Cu(2+), Cd(2+), Cr(3+), Fe(2+), and Fe(3+), had no significant effect on Hg(2+) detection. Moreover, the sensing system was used for the determination of Hg(2+) in river water samples with satisfactory results.