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1.
Int J Mol Sci ; 25(5)2024 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38474246

RESUMO

The DA1-like gene family plays a crucial role in regulating seed and organ size in plants. The DA1 gene family has been identified in several species but has not yet been reported in sweet potatoes. In this study, nine, eleven, and seven DA1s were identified in cultivated sweet potato (Ipomoea batatas, 2n = 6x = 90) and its two diploid wild relatives, I. trifida (2n = 2x = 30) and I. triloba (2n = 2x = 30), respectively. The DA1 genes were classified into three subgroups based on their phylogenetic relationships with Arabidopsis thaliana and Oryza sativa (rice). Their protein physiological properties, chromosomal localization, phylogenetic relationships, gene structure, promoter cis-elements, and expression patterns were systematically analyzed. The qRT-PCR results showed that the expression levels of four genes, IbDA1-1, IbDA1-3, IbDA1-6, and IbDA1-7, were higher in the sweet potato leaves than in the roots, fiber roots, and stems. In our study, we provide a comprehensive comparison and further the knowledge of DA1-like genes in sweet potatoes, and provide a theoretical basis for functional studies.


Assuntos
Ipomoea batatas , Ipomoea batatas/genética , Filogenia , Diploide , Genoma de Planta , Genes de Plantas , Regulação da Expressão Gênica de Plantas
2.
Opt Express ; 31(25): 42549-42561, 2023 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-38087626

RESUMO

Vortex beams that carry orbital angular moment (OAM) have recently attracted a great amount of research interest, and metasurfaces and planar microcavities have emerged as two prominent, but mostly separated, methods for Si chip-based vortex beam emission. In this work, we demonstrate in numerical simulation for the first time the hybridization of these two existing methods in a Si chip-based passive emitter (i.e., a light coupler). A unique feature of this device is its broken conjugate symmetry, which originates from introducing a metasurface phase gradient along a microring. The broken conjugate symmetry creates a new phenomenon that we refer to as asymmetric vortex beam emission. It allows two opposite input directions to generate two independent sets of OAM values, a capability that has never been reported before in Si chip-based passive emitters. In addition, we have also developed here a new analytical method to extract the OAM spectrum from a vector vortex beam. This analytical method will prove to be useful for vector vortex beam analysis, as mode purity analysis has rarely been reported in literature due to the complexity of the full-vector nature of such beams. This study provides new approaches for both the design and the analysis of integrated vortex beam emission, which could be utilized in many applications such as free-space optical communications and microfluidic particle manipulation.

3.
Opt Express ; 31(10): 15876-15887, 2023 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-37157678

RESUMO

Integration of metasurfaces and SOI (silicon-on-insulator) chips can leverage the advantages of both metamaterials and silicon photonics, enabling novel light shaping functionalities in planar, compact devices that are compatible with CMOS (complementary metal-oxide-semiconductor) production. To facilitate light extraction from a two-dimensional metasurface vertically into free space, the established approach is to use a wide waveguide. However, the multi-modal feature of such wide waveguides can render the device vulnerable to mode distortion. Here, we propose a different approach, where an array of narrow, single-mode waveguides is used instead of a wide, multi-mode waveguide. This approach tolerates nano-scatterers with a relatively high scattering efficiency, for example Si nanopillars that are in direct contact with the waveguides. Two example devices are designed and numerically studied as demonstrations: the first being a beam deflector that deflects light into the same direction regardless of the direction of input light, and the second being a light-focusing metalens. This work shows a straightforward approach of metasurface-SOI chip integration, which could be useful for emerging applications such as metalens arrays and neural probes that require off-chip light shaping from relatively small metasurfaces.

4.
Chem Rev ; 121(13): 8161-8233, 2021 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-34143612

RESUMO

Iron (Fe) is the fourth most abundant element in the earth's crust and plays important roles in both biological and chemical processes. The redox reactivity of various Fe(II) forms has gained increasing attention over recent decades in the areas of (bio) geochemistry, environmental chemistry and engineering, and material sciences. The goal of this paper is to review these recent advances and the current state of knowledge of Fe(II) redox chemistry in the environment. Specifically, this comprehensive review focuses on the redox reactivity of four types of Fe(II) species including aqueous Fe(II), Fe(II) complexed with ligands, minerals bearing structural Fe(II), and sorbed Fe(II) on mineral oxide surfaces. The formation pathways, factors governing the reactivity, insights into potential mechanisms, reactivity comparison, and characterization techniques are discussed with reference to the most recent breakthroughs in this field where possible. We also cover the roles of these Fe(II) species in environmental applications of zerovalent iron, microbial processes, biogeochemical cycling of carbon and nutrients, and their abiotic oxidation related processes in natural and engineered systems.

5.
Plant Cell Rep ; 43(1): 10, 2023 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-38135798

RESUMO

KEY MESSAGE: The inhibitory effect of eugenol on rice germination is mediated by a two-step modulatory process: Eugenol first regulates the antagonism of GA and ABA, followed by activation of catalase activity. The natural monoterpene eugenol has been reported to inhibit preharvest sprouting in rice. However, the inhibitory mechanism remains obscure. In this study, simultaneous monitoring of GA and ABA responses by the in vivo GA and ABA-responsive dual-luciferase reporter system showed that eugenol strongly inhibited the GA response after 6 h of imbibition, whereas eugenol significantly enhanced the ABA response after 12 h of imbibition. Gene expression analysis revealed that eugenol significantly induced the ABA biosynthetic genes OsNCED2, OsNCED3, and OsNCED5, but notably suppressed the ABA catabolic genes OsABA8ox1 and OsABA8ox2. Conversely, eugenol inhibited the GA biosynthetic genes OsGA3ox2 and OsGA20ox4 but significantly induced the GA catabolic genes OsGA2ox1 and OsGA2ox3 during imbibition. OsABI4, the key signaling regulator of ABA and GA antagonism, was notably induced before 12 h and suppressed after 24 h by eugenol. Moreover, eugenol markedly reduced the accumulation of H2O2 in seeds after 36 h of imbibition. Further analysis showed that eugenol strongly induced catalase activity, protein accumulation, and the expression of three catalase genes. Most importantly, mitigation of eugenol-inhibited seed germination was found in the catc mutant. These findings indicate that catalase associated with antagonistic changes of ABA and GA is involved in the sequential regulation of eugenol-inhibited seed germination in rice.


Assuntos
Ácido Abscísico , Oryza , Ácido Abscísico/farmacologia , Ácido Abscísico/metabolismo , Giberelinas/farmacologia , Giberelinas/metabolismo , Germinação , Oryza/metabolismo , Eugenol/farmacologia , Eugenol/metabolismo , Catalase/genética , Catalase/metabolismo , Peróxido de Hidrogênio/metabolismo , Sementes/metabolismo , Antioxidantes/metabolismo , Regulação da Expressão Gênica de Plantas
6.
Analyst ; 146(2): 487-494, 2021 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-33179652

RESUMO

A novel ferrocene-linked metal-covalent organic polymer (MCOP-NFC) was synthesized through the Claisen-Schmidt condensation reaction of 1,1'-diacetyl ferrocene and tris(4-formylphenyl)amine. MCOP-NFC acts as a highly efficient artificial enzyme for mimicking peroxidase, and shows good stability in harsh chemical environments including strong bases and acids, and boiling water. Based on the peroxidase-like activity of MCOP-NFC, a highly sensitive dual channel detection method for hydrogen peroxide was developed. For the colorimetric detection strategy, the limit of detection (LOD) reached 2.1 µM, while the limit of detection was found to be as low as 0.08 µM based on the electrochemical detection channel. This study offers a new strategy for the development of an enzyme mimetic on the basis of the covalent assembly of nanostructures, and the proposed electrochemical-colorimetric sensor for H2O2 detection has great potential for applications in biology and biomedicine.

7.
Environ Sci Technol ; 54(9): 5746-5754, 2020 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-32250598

RESUMO

The potential energy contained in the controlled mixing of waters with different salt concentrations (i.e., salinity gradient energy) can theoretically provide a substantial fraction of the global electrical demand. One method for generating electricity from salinity gradients is to use electrode-based reactions in electrochemical cells. Here, we examined the relationship between the electrical power densities generated from synthetic NaCl solutions and the crystal structures and morphologies of manganese oxides, which undergo redox reactions coupled to sodium ion uptake and release. Our aim was to make progress toward developing rational frameworks for selecting electrode materials used to harvest salinity gradient energy. We synthesized 12 manganese oxides having different crystal structures and particle sizes and measured the power densities they produced in a concentration flow cell fed with 0.02 and 0.5 M NaCl solutions. Power production varied considerably among the oxides, ranging from no power produced (ß-MnO2) to 1.18 ± 0.01 W/m2 (sodium manganese oxide). Power production correlated with the materials' specific capacities, suggesting that cyclic voltammetry may be a simple method to screen possible materials. The highest power densities were achieved with manganese oxides capable of intercalating sodium ions when their potentials were prepoised prior to power production.


Assuntos
Compostos de Manganês , Óxidos , Eletrodos , Manganês , Salinidade
8.
Langmuir ; 35(25): 8220-8227, 2019 06 25.
Artigo em Inglês | MEDLINE | ID: mdl-31140818

RESUMO

The interactions between organic ligands, Fe(II), and iron oxides are important in biogeochemical redox processes. The effect of phthalic acid (PHA) on the reductive reactivity of Fe(II) associated with goethite was examined using batch adsorption and kinetic studies, attenuated total reflectance?Fourier transform infrared spectroscopy (ATR?FTIR), and surface complexation modeling (SCM). PHA significantly inhibited the reductive reactivity of Fe(II)/goethite, as quantified by the pseudo-first-order reduction rate constants ( k) of p-cyanonitrobenzene. The k value decreased from 1.68 ? 0.03 to 0.338 ? 0.14 h?1 at pH 6.0 as the PHA concentration increased from 0 to 1000 ?M. The effects of the co-adsorption of Fe(II) and PHA onto goethite were then investigated to study the inhibition mechanism. The adsorption experiments showed that Fe(II) slightly enhanced PHA adsorption, whereas PHA did not affect Fe(II) adsorption, suggesting that the inhibition was not due to different amounts of Fe(II) adsorbed. The ATR?FTIR spectra of the adsorbed PHA in the ternary mixtures demonstrated that the major surface species was outer-sphere species, with minor inner-sphere complexes formed. SCM results showed that the presence of PHA (L) led to the formation of a type A ternary species ((?FeOFe+)2???L2?) on the goethite surface, decreasing the abundance of the reactive species (?FeOFeOH). Moreover, the adsorption of PHA on the surface of goethite might block the reactive sites and inhibit the electron transfer between Fe(II) and goethite, thus decreasing the reactivity. Overall, these findings provided new insights into the reaction mechanisms of surface-adsorbed Fe(II), which will facilitate the development of new technologies for site remediation and more accurate risk assessment.

9.
Inorg Chem ; 58(20): 13892-13901, 2019 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-31565936

RESUMO

Four diplatinum(II) complexes with the formula [Pt(pypm)(µ-Fn)]2 (2, 3a-c) bearing both a pyridine-pyrimidinate chelate and formamidinate bridge, where (pypm)H and FnH stand for 5-(pyridin-2-yl)-2-(trifluoromethyl)pyrimidine and functional formamidines with various substituents of iPr (n = 1), Ph (n = 2), C6H4tBu (n = 3), and C6H4CF3 (n = 4), were synthesized en route from a mononuclear intermediate represented by [Pt(pypm)Cl(F1H)] (1). Single-crystal X-ray diffraction studies confirmed the structure of 1 and 3a comprised of an individual "Pt(pypm)" unit and two "Pt(pypm)" units with a Pt···Pt distance of 2.8845(2) Å, respectively. Therefore, in contrast to the structured emission of mononuclear 1 with the first vibronic peak wavelength at 475 nm, all other diplatinum complexes with shortened Pt···Pt separation exhibited greatly red shifted and structureless metal-metal to ligand charge transfer (MMLCT) emission that extended into the near-infrared region in solid states. Their photophysical characteristics were measured under three distinctive morphological states (i.e., crystals, sublimed powders, and vacuum-deposited thin films) by steady-state UV-vis spectroscopy, while retention of Pt···Pt interactions in deposited thin films of 2 and 3a-c was confirmed using Raman spectroscopy, demonstrating lowered Pt···Pt stretching at 80-200 cm-1. Most importantly, complexes 3a-c exhibited a gradual red shift with the trends crystals < sublimed powders < vacuum-deposited thin films, a result of increased intermolecular π-π stacking interactions and Pt···Pt interactions, while crystalline samples exhibited the highest luminescence among all three morphological states due to the fewest defects in comparison to other morphologies. Finally, 3b was selected as a nondoped emitter for the fabrication of NIR-emitting OLEDs, giving an electroluminescence peak at 767 nm and a maximum external quantum efficiency of 0.14% with negligible roll-off.

10.
Int J Mol Sci ; 20(16)2019 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-31404948

RESUMO

Genome-editing techniques such as CRISPR/Cas9 have been widely used in crop functional genomics and improvement. To efficiently deliver the guide RNA and Cas9, most studies still rely on Agrobacterium-mediated transformation, which involves a selection marker gene. However, several limiting factors may impede the efficiency of screening transgene-free genome-edited plants, including the time needed to produce each life cycle, the response to selection reagents, and the labor costs of PCR-based genotyping. To overcome these disadvantages, we developed a simple and high-throughput method based on visual detection of antibiotics-derived H2O2 to verify transgene-free genome-edited plants. In transgenic rice containing hygromycin phosphotransferase (HPT), H2O2 content did not change in the presence of hygromycin B (HyB). In contrast, in transgenic-free rice plants with 10-h HyB treatment, levels of H2O2 and malondialdehyde, indicators of oxidative stress, were elevated. Detection of H2O2 by 3,3'-diaminobenzidine (DAB) staining suggested that H2O2 could be a marker to efficiently distinguish transgenic and non-transgenic plants. Analysis of 24 segregating progenies of an HPT-containing rice plant by RT-PCR and DAB staining verified that DAB staining is a feasible method for detecting transformants and non-transformants. Transgene-free genome-edited plants were faithfully validated by both PCR and the H2O2-based method. Moreover, HyB induced overproduction of H2O2 in leaves of Arabidopsis, maize, tobacco, and tomato, which suggests the potential application of the DAB method for detecting transgenic events containing HPT in a wide range of plant species. Thus, visual detection of DAB provides a simple, cheap, and reliable way to efficiently identify transgene-free genome-edited and HPT-containing transgenic rice.


Assuntos
Genoma de Planta , Peróxido de Hidrogênio/análise , Oryza/genética , Plantas Geneticamente Modificadas/genética , Sistemas CRISPR-Cas , Edição de Genes , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Proteínas de Plantas/genética , Transgenes
11.
Environ Sci Technol ; 52(19): 11309-11318, 2018 10 02.
Artigo em Inglês | MEDLINE | ID: mdl-30189143

RESUMO

Manganese dioxides (MnO2) are among important environmental oxidants in contaminant removal; however, most existing work has only focused on naturally abundant MnO2. We herein report the effects of different phase structures of synthetic MnO2 on their oxidative activity with regard to contaminant degradation. Bisphenol A (BPA), a frequently detected contaminant in the environment, was used as a probe compound. A total of eight MnO2 with five different phase structures (α-, ß-, γ-, δ-, and λ-MnO2) were successfully synthesized with different methods. The oxidative reactivity of MnO2, as quantified by pseudo-first-order rate constants of BPA oxidation, followed the order of δ-MnO2-1 > δ-MnO2-2 > α-MnO2-1 > α-MnO2-2 ≈ γ-MnO2 > λ-MnO2 > ß-MnO2-2 > ß-MnO2-1. Extensive characterization was then conducted for MnO2 crystal structure, morphology, surface area, reduction potential, conductivity, and surface Mn oxidation states and oxygen species. The results showed that the MnO2 oxidative reactivity correlated highly positively with surface Mn(III) content and negatively with surface Mn average oxidation state but correlated poorly with all other properties. This indicates that surface Mn(III) played an important role in MnO2 oxidative reactivity. For the same MnO2 phase structure synthesized by different methods, higher surface area, reduction potential, conductivity, or surface adsorbed oxygen led to higher reactivity, suggesting that these properties play a secondary role in the reactivity. These findings provide general guidance for designing active MnO2 for cost-effective water and wastewater treatment.


Assuntos
Compostos Benzidrílicos , Compostos de Manganês , Oxirredução , Estresse Oxidativo , Óxidos , Fenóis
12.
Mikrochim Acta ; 185(9): 414, 2018 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-30116901

RESUMO

The authors describe a method for electrochemical synthesis of a nanocomposite consisting of carboxylated multi-walled carbon nanotubes, polythionine and platinum nanoparticles (denoted as cMWCNT@pTh@Pt). The composite was placed on a glassy carbon electrode (GCE) to obtain a sensor for simultaneous determination of myricetin and rutin by differential pulse voltammetry, with typical peak voltages of 0.16 and 0.34 V (vs. SCE). Under optimal conditions, the modified GCE has a linear response in the range of 0.01-15 µM myricetin concentration range, and a 3 nM lower detection limit. For rutin, the data are 0.01-15 µM and 1.7 nM, respectively. The sensor is selective, stable and reproducible. It was successfully applied to the simultaneous determination of myricetin and rutin in spiked juice samples, and satisfactory results were obtained. Graphical abstract A nanocomposite consists of carboxy multi-walled carbon nanotube (cMWCNT), polythionine (pTh) and platinum nanoparticles (Pt) was presented for the simultaneous determination of myricetin and rutin. The nanocomposite shows excellent electrochemical determination performances based on a synergistic effect among cMWCNT, pTh and Pt.

13.
Anal Chem ; 89(16): 8358-8365, 2017 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-28700826

RESUMO

In this work, we first report a new application of coal as a novel modified electrode material in electrochemical sensing, achieving excellent electrochemical performance similar to graphene and making the utilization of coal become more multipurpose and more meaningful. Raw coal was first ball-milled, then centrifugated, and finally annealed, thus obtaining annealed coal that possesses lots of edge-plane-like defective sites, resulting in good electron-transfer efficiency and excellent electrocatalytic activity, which makes it promising when used as signal amplifier material and as a modified matrix in electrochemical sensing. And we also described an investigation into the electrochemical and spectroscopic properties of annealed coal samples and their application for the detection of electroactive redox molecules (rutin). Compared with other published carbon materials modified sensors, the annealed coal/chitosan/GCE sensor exhibited excellent electrocatalytic activity for the determination of rutin with good sensitivity, providing a wide linear detection range from 0.001 to 10 µmol dm-3 and a low detection limit of 0.2 nmol dm-3 (S/N = 3). Moreover, when the annealed coal/GCE sensor was applied for the determination of ascorbic acid, dopamine, uric acid, guanine, and adenine commonly contained in blood samples and urine samples, it also exhibited excellent detection performance with strong electrocatalytic activity. This research has opened up the application of coal in electroanalytical chemistry and held great promise for the sensing and biosensing application, which can be promising used as an alternative material of graphene.

14.
Anal Biochem ; 520: 9-15, 2017 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-28024754

RESUMO

An electrochemical sensor with high selectivity in addition to sensitivity was developed for the determination of cardiac troponin I (cTnI), based on the modification of cTnI imprinted polymer film on a glassy carbon electrode (GCE). The sensor was fabricated by layer-by-layer assembled graphene nanoplatelets (GS), multiwalled carbon nanotubes (MWCNTs), chitosan (CS), glutaraldehyde (GA) composites, which can increase the electronic transfer rate and the active surface area to capture a larger number of antigenic proteins. MWCNTs/GS based imprinted polymers (MIPs/MWCNTs/GS) were synthesized by means of methacrylic acid (MAA) as the monomer, ethylene glycol dimethacrylate (EGDMA) as the cross linker α,α'-azobisisobutyronitrile (AIBN) as the initiator and cTnI as the template. In comparison with conventional methods, the proposed electrochemical sensor is highly sensitive for cTnI, providing a better linear response range from 0.005 to 60 ng cm-3 and a lower limit of detection (LOD) of 0.0008 ng cm-3 under optimal experimental conditions. In addition, the electrochemical sensor exhibited good specificity, acceptable reproducibility and stability. Moreover, satisfactory results were obtained in real human serum samples, indicating that the developed method has the potential to find application in clinical detection of cTnI as an alternative approach.


Assuntos
Técnicas Eletroquímicas , Grafite/química , Impressão Molecular , Nanoestruturas/química , Nanotubos de Carbono/química , Troponina I/análise , Carbono/química , Eletrodos , Humanos , Limite de Detecção , Microscopia Eletrônica de Varredura , Miocárdio/metabolismo , Polímeros/química , Reprodutibilidade dos Testes , Espectroscopia de Infravermelho com Transformada de Fourier
15.
Opt Express ; 24(18): 20089-106, 2016 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-27607618

RESUMO

We demonstrate direct evidence for the first realization of atomically smooth sapphire crystalline fiber cores with a surface variation of only ~1.9 Å. The hybrid glass-clad crystalline cores were grown by a laser-based fiber drawing technique. Because of the improvement in crystal fiber quality, we were able, for the first time, to comprehensively and quantitatively elucidate the correlation between fiber nanostructure and optical loss. We also experimentally demonstrated that high-temperature treatment has a significant impact on defect relaxation and promotes excellent crystallinity, and hence enables low-loss optical wave guiding. The experimentally measured propagation losses in the order of 0.01-0.1 dB/cm are the lowest ever reported among conventional Ti:sapphire channel waveguides and ultrafast-laser-inscribed waveguides, and agree well with the theory. Through experiments and numerical calculation, we have demonstrated that low threshold and high efficiency of Ti:sapphire crystal fiber lasers are possible with the atomic-level roughness, low-loss propagation, and high crystallinity of the Ti:sapphire crystalline core.

16.
Environ Sci Technol ; 50(5): 2345-53, 2016 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-26845107

RESUMO

Our previous work reported that Al2O3 inhibited the oxidative reactivity of MnO2 through heteroaggregation between oxide particles and surface complexation of the dissolved Al ions with MnO2 (S. Taujale and H. Zhang, "Impact of interactions between metal oxides to oxidative reactivity of manganese dioxide" Environ. Sci. Technol. 2012, 46, 2764-2771). The aim of the current work was to investigate interactions in ternary mixtures of MnO2, Al2O3, and NOM and how the interactions affect MnO2 oxidative reactivity. For the effect of Al ions, we examined ternary mixtures of MnO2, Al ions, and NOM. Our results indicated that an increase in the amount of humic acids (HAs) increasingly inhibited Al adsorption by forming soluble Al-HA complexes. As a consequence, there was less inhibition on MnO2 reactivity than by the sum of two binary mixtures (MnO2+Al ions and MnO2+HA). Alginate or pyromellitic acid (PA)-two model NOM compounds-did not affect Al adsorption, but Al ions increased alginate/PA adsorption by MnO2. The latter effect led to more inhibition on MnO2 reactivity than the sum of the two binary mixtures. In ternary mixtures of MnO2, Al2O3, and NOM, NOM inhibited dissolution of Al2O3. Zeta potential measurements, sedimentation experiments, TEM images, and modified DLVO calculations all indicated that HAs of up to 4 mg-C/L increased heteroaggregation between Al2O3 and MnO2, whereas higher amounts of HAs completely inhibited heteroaggregation. The effect of alginate is similar to that of HAs, although not as significant, while PA had negligible effects on heteroaggregation. Different from the effects of Al ions and NOMs on MnO2 reactivity, the MnO2 reactivity in ternary mixtures of Al2O3, MnO2, and NOM was mostly enhanced. This suggests MnO2 reactivity was mainly affected through heteroaggregation in the ternary mixtures because of the limited availability of Al ions.


Assuntos
Óxido de Alumínio/química , Compostos de Manganês/química , Compostos Orgânicos/química , Óxidos/química , Adsorção , Benzoatos/química , Substâncias Húmicas/análise , Íons , Modelos Teóricos , Oxirredução , Solubilidade , Temperatura
17.
Langmuir ; 31(9): 2790-9, 2015 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-25652230

RESUMO

MnO2 typically coexists with iron oxides as either discrete particles or coatings in soils and sediments. This work examines the effect of Aldrich humic acid (AHA), alginate, and pyromellitic acid (PA) as representative natural organic matter (NOM) analogues on the oxidative reactivity of MnO2, as quantified by pseudo-first-order rate constants of triclosan oxidation, in mixtures with goethite or hematite. Adsorption studies showed that there was low adsorption of the NOMs by MnO2, but high (AHA and alginate) to low (PA) adsorption by the iron oxides. Based on the ATR-FTIR spectra obtained for the adsorbed PA on goethite or goethite + MnO2, the adsorption of PA occurred mainly through formation of outer-sphere complexes. The Fe oxides by themselves inhibited MnO2 reactivity through intensive heteroaggregation between the positively charged Fe oxides and the negatively charged MnO2; the low solubility of the iron oxides limited surface complexation of soluble Fe(3+) with MnO2. In ternary mixtures of MnO2, Fe oxides, and NOM analogues, the reactivity of MnO2 varied from inhibited to promoted as compared with that in the respective MnO2 + NOM binary mixtures. The dominant interaction mechanisms include an enhanced extent of homoaggregation within the Fe oxides due to formation of oppositely charged patches within the Fe oxides but an inhibited extent of heteroaggregation between the Fe oxide and MnO2 at [AHA] < 2-4 mg-C/L or [alginate/PA] < 5-10 mg/L, and an inhibited extent of heteroaggregation due to the largely negatively charged surfaces for all oxides at [AHA] > 4 mg-C/L or [alginate/PA] > 10 mg/L.

18.
Microorganisms ; 12(1)2024 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-38276201

RESUMO

The rumen is divided into multiple rumen sacs based on anatomical structure, and each has its unique physiological environment. Tarim wapiti preserved roughage tolerance after domestication, and adaptation to the desertified environment led to the development of a unique rumen shape and intraruminal environment. In this work, six Tarim wapiti were chosen and tested for fermentation parameters, microbes, and histomorphology in four rumen areas (Dorsal sac, DS; Ventral sac, VS; Caudodorsal blind sac, CDBS; Caudoventral blind sac, CVBS). Tarim wapiti's rumen blind sac had better developed rumen histomorphology, the ventral sac was richer in VFAs, and the dominant bacteria varied most notably in the phylum Firmicutes, which was enriched in the caudoventral blind sac. The ventral sac biomarkers focused on carbohydrate fermentation-associated bacteria, the dorsal sac focused on N recycling, and the caudoventral blind sac identified the only phylum-level bacterium, Firmicutes; we were surprised to find a probiotic bacterium, Bacillus clausii, identified as a biomarker in the ventral sac. This research provides a better understanding of rumen fermentation parameters, microorganisms, and histomorphology in the Tarim wapiti rumen within a unique ecological habitat, laying the groundwork for future regulation targeting the rumen microbiota and subsequent animal production improvement.

19.
Plants (Basel) ; 13(9)2024 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-38732433

RESUMO

Grain size has an important effect on rice yield. Although several key genes that regulate seed size have been reported in rice, their molecular mechanisms remain unclear. In this study, a rice small grain size 2 (sms2) mutant was identified, and MutMap resequencing analysis results showed that a 2 bp insertion in the second exon of the LOC_Os02g01590 gene resulted in a grain length and width lower than those of the wild-type Teqing (TQ). We found that SMS2 encoded vacuolar acid invertase, a novel allele of OsINV3, which regulates grain size. GO and KEGG enrichment analyses showed that SMS2 was involved in endoplasmic reticulum protein synthesis, cysteine and methionine metabolism, and propionic acid metabolism, thereby regulating grain size. An analysis of sugar content in young panicles showed that SMS2 reduced sucrose, fructose, and starch contents, thus regulating grain size. A haplotype analysis showed that Hap2 of SMS2 had a longer grain and was widely present in indica rice varieties. Our results provide a new theoretical basis for the molecular and physiological mechanisms by which SMS2 regulates grain size.

20.
Environ Pollut ; 325: 121433, 2023 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-36907241

RESUMO

Anthropogenic activities pose a more significant threat to the environment than natural phenomena by contaminating the environment with heavy metals. Cadmium (Cd), a highly poisonous heavy metal, has a protracted biological half-life and threatens food safety. Plant roots absorb Cd due to its high bioavailability through apoplastic and symplastic pathways and translocate it to shoots through the xylem with the help of transporters and then to the edible parts via the phloem. The uptake and accumulation of Cd in plants pose deleterious effects on plant physiological and biochemical processes, which alter the morphology of vegetative and reproductive parts. In vegetative parts, Cd stunts root and shoot growth, photosynthetic activities, stomatal conductance, and overall plant biomass. Plants' male reproductive parts are more prone to Cd toxicity than female reproductive parts, ultimately affecting their grain/fruit production and survival. To alleviate/avoid/tolerate Cd toxicity, plants activate several defense mechanisms, including enzymatic and non-enzymatic antioxidants, Cd-tolerant gene up-regulations, and phytohormonal secretion. Additionally, plants tolerate Cd through chelating and sequestering as part of the intracellular defensive mechanism with the help of phytochelatins and metallothionein proteins, which help mitigate the harmful effects of Cd. The knowledge on the impact of Cd on plant vegetative and reproductive parts and the plants' physiological and biochemical responses can help selection of the most effective Cd-mitigating/avoiding/tolerating strategy to manage Cd toxicity in plants.


Assuntos
Metais Pesados , Poluentes do Solo , Cádmio/metabolismo , Biodegradação Ambiental , Metais Pesados/metabolismo , Plantas/metabolismo , Fotossíntese , Raízes de Plantas/metabolismo , Poluentes do Solo/metabolismo
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