Electrochemical Biosensor for Protein Concentration Monitoring Using Natural Wood Evaporation for Power Generation.

A high-sensitivity, low-cost, self-powered biomass electrochemical biosensor based on the "evaporating potential" theory is developed for protein detection. The feasibility of experimental evaluation methods was verified with a probe protein of bovine serum albumin. The sensor was then used to detect lung cancer marker CYFRA21-1, and the potential of our sensor for clinical diagnosis was demonstrated by serum analysis. This work innovatively exploits the osmotic power generation capability of natural wood to construct a promising electrochemical biosensor that was driven by kinetics during testing. The detection methods used for this sensor, chronoamperometry and AC impedance, showed potential for quantitative analysis and specific detection, respectively. Furthermore, the sensor could facilitate new insights into the development of high-sensitivity, low-cost, and easy-to-use electrochemical biosensors.

Removal of Ciprofloxacin from Water by a Potassium Carbonate-Activated Sycamore Floc-Based Carbonaceous Adsorbent: Adsorption Behavior and Mechanism.

In this study, a porous carbonaceous adsorbent was prepared from sycamore flocs by pyrolysis method and K2CO3 activation. The effects of preparative conditions of the material on its adsorptive property were explored. The optimal material (SFB2-900) was obtained with a K2CO3/biochar mass ratio of 2:1 at an activation temperature of 900 °C, possessing a huge surface specific area (1651.27 m2/g). The largest adsorption capacity for ciprofloxacin on SFB2-900 was up to 430.25 mg/g. The adsorption behavior was well described by the pseudo-second-order kinetic model and the Langmuir isothermal model. Meanwhile, this process was spontaneous and exothermic. The obtained material showed excellent adsorption performance in the conditions of diverse pH range, ionic strength, and water quality of the solution. The optimum adsorption conditions (pH = 7.01, dosage = 0.6 g/L, and C0 = 52.94 mg/L) determined based on the response surface methodology were in accordance with the practical validation consequences. The good regeneration effect of SFB2-900 manifested that this material had great practical application potential. Combining the experimental results and density functional theory calculation results, the adsorption mechanisms mainly included pore filling, π-π EDA interactions, electrostatic interactions, and H-bonds. The material could be regarded as a novel and high-efficiency adsorbent for antibiotics. Additionally, these findings also provide reference for the reuse of waste biomass in water treatment.

A Rust Extraction and Evaluation Method for Navigation Buoys Based on Improved U-Net and Hue, Saturation, and Value.

Abnormalities of navigation buoys include tilting, rusting, breaking, etc. Realizing automatic extraction and evaluation of rust on buoys is of great significance for maritime supervision. Severe rust may cause damage to the buoy itself. Therefore, a lightweight method based on machine vision is proposed for extracting and evaluating the rust of the buoy. The method integrates image segmentation and processing. Firstly, image segmentation technology is used to extract the metal part of the buoy based on an improved U-Net. Secondly, the RGB image is converted into an HSV image by preprocessing, and the transformation law of HSV channel color value is analyzed to obtain the best segmentation threshold and then the pixels of the rusted and the metal parts can be extracted. Finally, the rust ratio of the buoy is calculated to evaluate the rust level of the buoy. Results show that both the segmentation precision and recall are above 0.95, and the accuracy is nearly 1.00. Compared with the rust evaluation algorithm directly using the image processing method, the accuracy and processing speed of rust grade evaluation are greatly improved.

Quercetin inhibits the activity and function of dendritic cells through the TLR4/IRAK4/NF-κB signalling pathway.

Introduction: To investigate the inhibitory effect of quercetin (QUE) on dendritic cells (DCs) through the toll-like receptor 4/interleukin-1 receptor-associated kinase 4/nuclear factor kappa-B (TLR4/IRAK4/NF-κB) signalling pathway. Material and methods: CCK-8 and apoptosis assays were performed to determine the optimal concentration and action time of QUE to inhibit DCs. Protein extracts from treated DCs were used for Western blotting experiments to determine the relative expression levels of TLR4, IRAK4, and NF-κB p65 proteins. Changes in the ratio of CD86 and CD11c positive cells on the DCs surface were detected using flow cytometry. The molecular docking technique was used to analyse the binding site and free energy of QUE and IRAK4. Results: CCK-8 and apoptosis assays suggested that QUE inhibited the activity and function of DCs in a time-dose-dependent manner. The results of Western blotting suggested that the relative expression levels of TLR4, IRAK4, and NF-κB p65 proteins were increased in the lipopolysaccharide (LPS) group compared with the normal control group, and the relative expression of the above proteins was decreased after treatment with QUE and IRAK4-IN-4. The results of flow cytometry suggested that LPS increased the expression of CD86 and CD11c on the surface of DCs, and QUE and IRAK4-IN-4 decreased the expression of CD86 and CD11c induced by LPS. Molecular docking results showed that the binding sites of QUE and IRAK4 were stable, with the minimum binding energies comparable to that of IRAK4-IN-4. Conclusions: Quercetin may inhibit the activity and function of DCs through the TLR4/IRAK4/NF-κB signalling pathway, and IRAK4 may be its target.

Identification of a candidate gene underlying qHKW3, a QTL for hundred-kernel weight in maize.

KEY MESSAGE: qHKW3, a quantitative trait locus for hundred-kernel weight, harbors the proposed causal gene Zm00001d044081, encoding a homeobox-leucine zipper protein (ATHB-4) that might affect kernel size and weight. Kernel size and weight are key traits that contribute greatly to grain yield per year in maize (Zea mays). Here, we developed the chromosome segment substitution line (CSSL), H15-6-2, with smaller kernel size and lower kernel weight across environments compared to the background line Ye478. Histological analysis suggested that a slower kernel filling rate of H15-6-2 contributes to its small-kernel size and reduced hundred-kernel weight. We identified a quantitative trait locus (QTL) explaining 23% of the phenotypic variation in hundred-kernel weight. This QTL, qHKW3, was fine mapped to an interval of approximately 40.66-kb harboring the gene Zm00001d044081. The upstream sequence and its expression level of Zm00001d044081 in kernels at 6 days after pollination (DAP) showed obvious differences between the near-isogenic lines HKW3Ye478 and HKW3H15-6-2. We further confirmed the effects of the Zm00001d044081 promoter on maize kernel size and weight in an independent association mapping panel with 513 lines by candidate regional association analysis. We propose that Zm00001d044081, which encodes the homeobox-leucine zipper protein ATHB-4, is the causal gene of qHKW3, representing an attractive target for the genetic improvement of maize yield.

Lifestyle as well as metabolic syndrome and non-alcoholic fatty liver disease: an umbrella review of evidence from observational studies and randomized controlled trials.

BACKGROUND & AIMS: Recent epidemiological studies have indicated that NAFLD is pathologically associated with a sedentary lifestyle, unhealthy dietary habits and metabolic syndrome. An umbrella review of meta-analyses was performed to summarize the quality of evidence regarding the epidemiologic associations between lifestyle, metabolic syndrome, and non-alcoholic fatty liver disease (NAFLD) in regards to risk and treatment. METHODS: We searched PubMed, Web of Science and Embase Database from inception until June 1, 2021. Meta-analyses of observational studies and randomized controlled trials (RCTs) examining the associations of lifestyle as well as metabolic syndrome with NAFLD risk or treatment were screened. We assessed meta-analyses of observational studies based on random-effect summary effect sizes and their P values, 95% prediction intervals, heterogeneity, and small-study effects. For meta-analyses of RCTs, outcomes with a random-effect P < 0.005 and a high-GRADE assessment were classified as strong evidence. RESULTS: A total of 37 publications were included in this review: twenty-two publications reporting 41 meta-analyses of observational studies (37 unique outcomes) and 15 publications reporting 81 meta-analyses of RCTs (63 unique outcomes) met the inclusion criteria. Methodological quality was high for 97% of the included meta-analyses. Quality of evidence was rated high only for the association of sugar-sweetened soda consumption with increased NAFLD risk in meta-analyses of observational studies. Only 3 therapeutic interventions (green tea improving ALT, TG, TC and LDL, omega-3 PUFAs improving HOMR-IR and plasma glucose, and exercise improving RT and ALT) from meta -analyses of RCTs with suggestive (change to high/low/etc) levels of evidence were identified. CONCLUSION: Despite many meta-analyses exploring the associations of lifestyle as well as metabolic syndrome with the risk or treatment of NAFLD, robust clinical RCTs are needed to further investigate the associations between lifestyle modifications and incidence of NAFLD or therapeutic effects on disease progression.

Starch phosphorylase 2 is essential for cellular carbohydrate partitioning in maize.

Carbohydrate partitioning is essential for plant growth and development, and its hindrance will result in excess accumulation of carbohydrates in source tissues. Most of the related mutants in maize (Zea mays L.) display impaired whole-plant sucrose transport, but other mechanisms affecting carbohydrate partitioning have seldom been reported. Here, we characterized chlorotic leaf3 (chl3), a recessive mutation causing leaf chlorosis with starch accumulation excessively in bundle sheath chloroplasts, suggesting that chl3 is defective in carbohydrate partitioning. Positional cloning revealed that the chl3 phenotype results from a frameshift mutation in ZmPHOH, which encodes starch phosphorylase 2. Two mutants in ZmPHOH exhibited the same phenotype as chl3, and both alleles failed to complement the chl3 mutant phenotype in an allelism test. Inactivation of ZmPHOH in chl3 leaves reduced the efficiency of transitory starch conversion, resulting in increased leaf starch contents and altered carbohydrate metabolism patterns. RNA-seq revealed the transcriptional downregulation of genes related to photosynthesis and carbohydrate metabolism in chl3 leaves compared to the wild type. Our results demonstrate that transitory starch remobilization is very important for cellular carbohydrate partitioning in maize, in which ZmPHOH plays an indispensable role.

Loss of Function of an RNA Polymerase III Subunit Leads to Impaired Maize Kernel Development.

Kernel size is an important factor determining grain yield. Although a number of genes affecting kernel development in maize (Zea mays) have been identified by analyzing kernel mutants, most of the corresponding mutants cannot be used in maize breeding programs due to low germination or incomplete seed development. Here, we characterized small kernel7, a recessive small-kernel mutant with a mutation in the gene encoding the second-largest subunit of RNA polymerase III (RNAPΙΙΙ; NRPC2). A frame shift in ZmNRPC2 leads to a premature stop codon, resulting in significantly reduced levels of transfer RNAs and 5S ribosomal RNA, which are transcribed by RNAPΙΙΙ. Loss-of-function nrpc2 mutants created by CRISPR/CAS9 showed significantly reduced kernel size due to altered endosperm cell size and number. ZmNRPC2 affects RNAPIII activity and the expression of genes involved in cell proliferation and endoreduplication to control kernel development via physically interacting with RNAPIII subunits RPC53 and AC40, transcription factor class C1 and Floury3. Notably, unlike the semidominant negative mutant floury3, which has defects in starchy endosperm, small kernel7 only affects kernel size but not the composition of kernel storage proteins. Our findings provide novel insights into the molecular network underlying maize kernel size, which could facilitate the genetic improvement of maize in the future.

Fine mapping of a kernel length-related gene with potential value for maize breeding.

KEY MESSAGE: A key candidate gene for maize kernel length was fine mapped to an interval of 942 kb; the locus significantly increases kernel length (KL) and hundred-kernel weight (HKW). Kernel size is a major determinant of yield in cereals. Kernel length, one of the determining factors of kernel size, is a target trait for both domestication and artificial breeding. However, there are few reports of fine mapping and quantitative trait loci (QTLs)/cloned genes for kernel length in maize. In this project, a novel major QTL, named qKL9, controlling maize kernel length was identified. We verified the authenticity and stability of qKL9 via BC2F2 and BC3F1 populations, respectively, and ultimately mapped qKL9 to an ~ 942-kb genomic interval by testing the progenies of recombination events derived from BC3F2 and BC4F2 populations in multiple environments. Additionally, one new line (McqKL9-A) containing the ~ 942-kb segment was screened from the BC4F2 population. Combining transcriptome analysis between McqKL9-A and Mc at 6, 9 and 14 days after pollination and candidate regional association mapping, Zm00001d046723 was preliminarily identified as the key candidate gene for qKL9. Importantly, the replacement in the Mc line of the Mc's alleles by the V671's alleles in the qKL9 region improved the performances of single-cross hybrids obtained with elite lines, illustrating the potential value of this QTL for the genetic improvement in maize kernel-related traits. These findings facilitate molecular breeding for kernel size and cloning of the gene underlying qKL9, shedding light on the genetic basis of kernel size in maize.

LncRNA HOXC-AS1 promotes nasopharyngeal carcinoma (NPC) progression by sponging miR-4651 and subsequently upregulating FOXO6.

The incidence rate of nasopharyngeal carcinoma (NPC) is the highest among the malignant tumors of otorhinolaryngology, posing a huge burden to public health. Long noncoding RNAs (lncRNAs) exert an important role in tumorigenesis and the progression of various cancers. The present study found that HOXC-AS1 was highly expressed in NPC and in NPC cell lines, suggesting a critical role of HOXC-AS1 in NPC progression. In addition, the abundance of HOXC-AS1 was negatively correlated with the prognosis of NPC. To molecularly dissect the mechanism of HOXC-AS1 in NPC progression, we knocked down the expression of HOXC-AS1 in HNE1 and C666-1 cells. Then, we employed CCK8, colony-formation experiment and Transwell to investigate how the cell performed when HOXC-AS1 was knocked down. It could be observed that HOXC-AS1 knockdown decreases cell proliferation, migration and invasion, but induces cell apoptosis in NPC. We found that HOXC-AS1 could sponge miR-4651 subsequently binding FOXO6 and inhibiting its expression. Therefore, HOXC-AS1/miR-4651/FOXO6 may form a competing endogenous RNA (ceRNA) network that promotes NPC progression. In conclusion, our study demonstrates that HOXC-AS1 promotes NPC progression by sponging miR-4651 and regulating FOXO6 expression, thus providing potential pharmaceutical targets for developing new NPC treatments.

Knockdown NRPC2, 3, 8, NRPABC1 and NRPABC2 Affects RNAPIII Activity and Disrupts Seed Development in Arabidopsis.

RNA polymerase III (RNAPIII) contains 17 subunits forming 4 functional domains that control the different stages of RNAPIII transcription and are dedicated to the synthesis of small RNAs such as 5S rRNA and tRNAs. Here, we identified 23 genes encoding these subunits in Arabidopsis (Arabidopsis thaliana) and further analyzed 5 subunits (NRPC2, NRPC3, NRPC8, NRPABC1, and NRPABC2) encoded by 6 genes with different expression patterns and belonging to different sub-complexes. The knockdown of these genes repressed the expression of 5S rRNA and tRNAs, causing seed developmental arrest at different stages. Among these knockdown mutants, RNA-seq analysis revealed 821 common differentially expressed genes (DEGs), significantly enriched in response to stress, abscisic acid, cytokinins, and the jasmonic acid signaling pathway. Weighted gene co-expression network analysis (WGCNA) revealed several hub genes involved in embryo development, carbohydrate metabolic and lipid metabolic processes. We identified numerous unique DEGs between the mutants belonging to pathways, including cell proliferation, ribosome biogenesis, cell death, and tRNA metabolic processes. Thus, NRPC2, NRPC3, NRPC8, NRPABC1, and NRPABC2 control seed development in Arabidopsis by influencing RNAPIII activity and, thus, hormone signaling. Reduced expression of these subunit genes causes an insufficient accumulation of the total RNAPIII, leading to the phenotypes observed following the genetic knockdown of these subunits.

Long noncoding RNA 91H overexpression contributes to the growth and metastasis of HCC by epigenetically positively regulating IGF2 expression.

BACKGROUND & AIMS: Long noncoding RNA 91H is transcribed from the H19/IGF2 locus and contributes to the development of breast and oesophagus cancers by regulating the expression of IGF2, but the regulation mechanism remains poorly characterized. Here, we explored the role of 91H in hepatocellular carcinoma (HCC) and the mechanism of IGF2 expression regulation by 91H. METHODS: Firstly, the expression of 91H was analysed in HCC by quantitative RT-PCR, the association of 91H with survival was evaluated by the Kaplan-Meier method and the effect of 91H on the growth and invasion of HCC was investigated by the in vitro and in vivo studies. Then, the association of 91H with the expression of IGF2 was evaluated in HCC tissues, and the effect of 91H on the expression of IGF2 was investigated by 91H knockdown. Finally, the binding of RBBP5 to 91H and the binding of RBBP5, activating H3K4me3 mark and repressive H3K27me3 mark to the P3 and P4 promoters of IGF2 gene were studied by RIP and ChIP respectively. RESULTS: The overexpression of 91H was found in HCC and in association with the growth, metastasis and shorter survival time of HCC. The knockdown of 91H down-regulated the IGF2 expression in HCC, and the mechanism was correlated with the decreased enrichment of RBBP5 and H3K4me3 and increased enrichment of H3K27me3 at the bivalent P3 and P4 promoters. CONCLUSIONS: The overexpression of 91H promotes tumour growth and metastasis, and is associated with a poor prognosis of HCC at least partially by positively regulating the expression of IGF2 through bivalent histone modification changes characterized by H3K4me3 and H3K27me3 at the P3 and P4 promoters.

ZmSRL5 is involved in drought tolerance by maintaining cuticular wax structure in maize.

Cuticular wax is a natural barrier on terrestrial plant organs, which protects plants from damages caused by a variety of stresses. Here, we report the identification and functional characterization of a cuticular-wax-related gene, Zea mays L. SEMI-ROLLED LEAF 5 (ZmSRL5). The loss-of-function mutant srl5, which was created by a 3,745 bp insertion in the first intron that led to the premature transcript, exhibited abnormal wax crystal morphology and distribution, which, in turn, caused the pleiotropic phenotypes including increased chlorophyll leaching and water loss rate, decreased leaf temperature, sensitivity to drought, as well as semi-rolled mature leaves. However, total wax amounts showed no significant difference between wild type and semi-rolled leaf5 (srl5) mutant. The phenotype of srl5 was confirmed through the generation of two allelic mutants using CRISPR/Cas9. ZmSRL5 encodes a CASPARIAN-STRIP-MEMBRANE-DOMAIN-LIKE (CASPL) protein located in plasma membrane, and highly expressed in developing leaves. Further analysis showed that the expressions of the most wax related genes were not affected or slightly altered in srl5. This study, thus, primarily uncovers that ZmSRL5 is required for the structure formation of the cuticular wax and could increase the drought tolerance by maintaining the proper cuticular wax structure in maize.

A group VII ethylene response factor gene, ZmEREB180, coordinates waterlogging tolerance in maize seedlings.

Group VII ethylene response factors (ERFVIIs) play important roles in ethylene signalling and plant responses to flooding. However, natural ERFVII variations in maize (ZmERFVIIs) that are directly associated with waterlogging tolerance have not been reported. Here, a candidate gene association analysis of the ZmERFVII gene family showed that a waterlogging-responsive gene, ZmEREB180, was tightly associated with waterlogging tolerance. ZmEREB180 expression specifically responded to waterlogging and was up-regulated by ethylene; in addition, its gene product localized to the nucleus. Variations in the 5'-untranslated region (5'-UTR) and mRNA abundance of this gene under waterlogging conditions were significantly associated with survival rate (SR). Ectopic expression of ZmEREB180 in Arabidopsis increased the SR after submergence stress, and overexpression of ZmEREB180 in maize also enhanced the SR after long-term waterlogging stress, apparently through enhanced formation of adventitious roots (ARs) and regulation of antioxidant levels. Transcriptomic assays of the transgenic maize line under normal and waterlogged conditions further provided evidence that ZmEREB180 regulated AR development and reactive oxygen species homeostasis. Our study provides direct evidence that a ZmERFVII gene is involved in waterlogging tolerance. These findings could be applied directly to breed waterlogging-tolerant maize cultivars and improve our understanding of waterlogging stress.

Enhanced Adsorption of Aqueous Tetracycline Hydrochloride on Renewable Porous Clay-Carbon Adsorbent Derived from Spent Bleaching Earth via Pyrolysis.

In this study, spent bleaching earth (SBE) and pyrolyzed SBE (SBE@C) were tested for their capacity to remove tetracycline hydrochloride (TCH) from aqueous solution. The maximum adsorption capacity obtained by the Langmuir model is 0.114 mmol/g for SBE@C and 0.087 mmol/g for SBE. The deleterious effects of coexisting cations were ranked in a decline: Al3+ > Mg2+ > Na+. The results of various characterization methods show that the adsorption mechanisms mainly included π-π interactions, hydrogen bonding, electrostatic interactions, and changes in physical and chemical properties. After 3 repeated cycles of pyrolysis, the adsorption capacity of SBE@C remained at 85.4%, with SBE@C potentially recycled 21 times before complete loss of adsorption capacity. Furthermore, the problem of secondary pollution caused by SBE and residual oil is resolved by the use of SBE@C. All results indicate that SBE@C is a likely candidate for the treatment of TCH wastewater in the coming practical applications.

Atmospheric Initial Nucleation Containing Carboxylic Acids.

The possible involvement of chemical components in atmospheric new particle formation has received increased attention in recent years. However, the deep understanding of the clusters formed between atmospheric gas-phase organic acids is incomplete. In this work, the chemical and physical properties of the cluster formed between three organic acids [glyoxylic acid (GA), oxalic acid (OA), and pyruvic acid (PA)] with common atmospheric nucleation precursors [methyl hydrogen sulfate (MHS), methanesulfonic acid (MSA), and hydroxymethanesulfonic acid (HMSA)] have been investigated with density functional theory and ab initio coupled-cluster singles and doubles with perturbative triples (CCSD(T)) theory. Six- to nine-membered cyclic ring structures are mainly arranged via two classes of intermolecular hydrogen bonds: SO-H···O and CO-H···O. The GA/OA/PA-MHS/MSA/HMSA complexes with the nine- and eight-membered cyclic ring structures are thermodynamically more stable than the others. Large red shifts of the OH-stretching vibrational frequencies of both SO-H···O (354-794 cm-1) and CO-H···O (320-481 cm-1) are obtained with regard to the isolated gas monomers. Atoms in molecules topological analysis reveals that the Laplacian of the charge density of the bimolecular interactions in the GA/OA/PA-MHS/MSA/HMSA complexes is higher than the upper value of the hydrogen bond criteria. The thermodynamic data, dipole moments, and atmospheric mixing ratios indicate that the MHS- and MSA-containing complexes possibly take part in atmospheric new particle formation. Additionally, the environmental factors, such as temperature and pressure, are also important in atmospheric particle nucleation, and the gas-mixing ratios of the clusters at 12 km are much enhanced by 18-44 times with respect to the ones at the ground level. This study suggests that small cluster calculations may be helpful in simulating atmospheric new particle formation.

Emp10 encodes a mitochondrial PPR protein that affects the cis-splicing of nad2 intron 1 and seed development in maize.

In higher plants, many mitochondrial genes contain group II-type introns that are removed from RNAs by splicing to produce mature transcripts that are then translated into functional proteins. However, the factors involved in the splicing of mitochondrial introns and their biological functions are not well understood in maize. Here, we isolated an empty pericarp 10 (emp10) mutant and identified the underlying gene by map-based cloning. Emp10 encodes a P-type mitochondria-targeted pentatricopeptide repeat (PPR) protein with 10 PPR motifs. Loss of Emp10 function results in splicing defect of the first intron of nad2, a gene encoding subunit 2 of NADH dehydrogenase (also called complex I). The emp10 mutant has undetectable activity of complex I and has arrested development of embryo and endosperm, and thus defective seeds with empty pericarp. Additionally, the basal endosperm transfer layer cells were severely affected, indicating the deficiency of cell wall ingrowths in the emp10 kernels. Moreover, the alternative respiratory pathway involving alternative oxidase was significantly induced in the emp10 mutant. These results suggest that EMP10 is specifically required for the cis-splicing of mitochondrial nad2 intron 1, embryogenesis and endosperm development in maize.

Dissecting the genetic architecture of waterlogging stress-related traits uncovers a key waterlogging tolerance gene in maize.

KEY MESSAGE: A key candidate gene, GRMZM2G110141, which could be used in marker-assisted selection in maize breeding programs, was detected among the 16 genetic loci associated with waterlogging tolerance identified through genome-wide association study. Waterlogging stress seriously affects the growth and development of upland crops such as maize (Zea mays L.). However, the genetic basis of waterlogging tolerance in crop plants is largely unknown. Here, we identified genetic loci for waterlogging tolerance-related traits by conducting a genome-wide association study using maize phenotypes evaluated in the greenhouse under waterlogging stress and normal conditions. A total of 110 trait-single nucleotide polymorphism associations spanning 16 genomic regions were identified; single associations explained 2.88-10.67% of the phenotypic variance. Among the genomic regions identified, 14 co-localized with previously detected waterlogging tolerance-related quantitative trail loci. Furthermore, 33 candidate genes involved in a wide range of stress-response pathways were predicted. We resequenced a key candidate gene (GRMZM2G110141) in 138 randomly selected inbred lines and found that variations in the 5'-UTR and in the mRNA abundance of this gene under waterlogging conditions were significantly associated with leaf injury. Furthermore, we detected favorable alleles of this gene and validated the favorable alleles in two different recombinant inbred line populations. These alleles enhanced waterlogging tolerance in segregating populations, strongly suggesting that GRMZM2G110141 is a key waterlogging tolerance gene. The set of waterlogging tolerance-related genomic regions and associated markers identified here could be valuable for isolating waterlogging tolerance genes and improving this trait in maize.

Heterogeneous reactions of SO2 on the hematite(0001) surface.

Heterogeneous reactions at the surfaces of mineral dusts represent a key process in the formation of atmospheric aerosols. To quantify the rate of aerosol formation in climate modeling as well as combat hazardous aerosols, a deep understanding of the mechanisms of these reactions is essential. In the present work, density functional theory calculations, including a Hubbard-like +U correction, were employed to elucidate the reaction between SO2 and the hematite(0001) surface. Three reaction conditions are considered: dry, wet, and aerobic. In the absence of water and oxygen, adsorption energies of SO2 on the clean Fe-O3-Fe-termination were found to be about -0.8 to -1.0 eV and resulted in the formation of an adsorbed SO3-like species. The addition of water leads to surface hydroxylation and has little effect on promoting the SO2 adsorption. Under such circumstances, an HSO3-like species was formed with a smaller adsorption energy of about -0.5 eV. By contrast, the presence of molecular oxygen enhances the SO2 adsorption significantly as the two species combine to form sulfate SO4 2-, with adsorption energies of -1.31 to -1.64 eV. The calculated vibrational frequencies of the adsorbate species provide insight into the surface bonding and a useful spectral fingerprinting for experimental measurements. These results elucidate the atomistic mechanism of the reaction between SO2 and hematite and highlight the important role of atmospheric O2 in the formation of sulfates.