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1.
Colloids Surf B Biointerfaces ; 240: 113972, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38810469

RESUMO

Magnesium (Mg) and its alloys were favored by biomedical practitioners thanks to availability of bioactivity and degradability. However, the mismatch between the degradation properties of Mg alloys and the rate of osteogenesis often led to implant failure and bacterial infections within the desired period. The goal of this study was to improve the corrosion resistance of Mg alloys, providing theoretical guidance for solving the problems of implantable Mg-based materials. In this experiment, we prepared a dense and uniform BTESPT/TiO2 film layer on the surface of Mg substrate by electrochemically assisted deposition. The BTESPT/TiO2 film layer provided a physical barrier to avoid direct contact between AZ31 and the corrosive medium. When the addition amount was 2 g/L TiO2, the coating had the best corrosion resistance behavior, its corrosion current density could be up to 9.973×10-8 A/cm2. The BTESPT/TiO2 revealed good cell viability as well as osteogenic differentiation potential on MC3T3-E1 cells.


Assuntos
Ligas , Técnicas Eletroquímicas , Magnésio , Titânio , Titânio/química , Titânio/farmacologia , Ligas/química , Ligas/farmacologia , Camundongos , Animais , Magnésio/química , Corrosão , Propriedades de Superfície , Osteogênese/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Sulfetos/química , Linhagem Celular , Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/farmacologia
2.
Biosens Bioelectron ; 259: 116371, 2024 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-38761742

RESUMO

The work was based on N-(4-Aminobutyl)-N-ethylisoluminol (ABEI)-functionalized Fe-MIL-101 and gold nanoparticles (AuNPs) as sensing materials, and an electrochemiluminescence (ECL) aptasensor was constructed for detecting acetamiprid. As a metal-organic framework (MOF) material, Fe-MIL-101, was renowned for its unique three-dimensional network structure and efficient catalytic capability. ABEI, a common ECL reagent, was widely applied. ABEI was introduced into the Fe-MIL-101 structure as a luminescence functionalization reagent to form Fe-MIL-101@ABEI. This approach avoided limitations on the loading capacity of luminescent reagents imposed by modification and encapsulation methods. With character of excellent catalytic activity and ease of bioconjugation, AuNPs offered significant advantages in biosensing. Leveraging the reductive properties of ABEI, AuNPs were reduced around Fe-MIL-101@ABEI, resulting in the modified luminescent functionalized material denoted as Fe-MIL-101@ABEI@AuNPs. An aptamer was employed as a recognition element and was modified accordingly. The aptamer was immobilized on Fe-MIL-101@ABEI@AuNPs through gold-sulfur (Au-S) bonds. After capturing acetamiprid, the aptamer induced a decrease in the ECL signal intensity within the ABEI-hydrogen peroxide (H2O2) system, enabling the quantitative detection of acetamiprid. The aptasensor displayed remarkable stability and repeatability, featured a detection range of 1×10-3-1×102 nM, and had a limit of detection (LOD) of 0.3 pM (S/N=3), which underscored its substantial practical application potential.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Técnicas Eletroquímicas , Ouro , Limite de Detecção , Medições Luminescentes , Nanopartículas Metálicas , Estruturas Metalorgânicas , Neonicotinoides , Neonicotinoides/análise , Neonicotinoides/química , Estruturas Metalorgânicas/química , Técnicas Biossensoriais/métodos , Nanopartículas Metálicas/química , Ouro/química , Aptâmeros de Nucleotídeos/química , Medições Luminescentes/métodos , Técnicas Eletroquímicas/métodos , Verduras/química , Luminol/química , Luminol/análogos & derivados , Resíduos de Praguicidas/análise , Resíduos de Praguicidas/isolamento & purificação , Contaminação de Alimentos/análise
3.
J Fluoresc ; 2024 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-38709378

RESUMO

The double perovskite structure of Ca2GdSbO6 as a fluorescent phosphor matrix material possesses a stable structure, making it an excellent candidate for a matrix material. In this study, single-doped Ca2GdSbO6: Eu3+ fluorescent phosphors and Bi3+ sensitized Ca2GdSbO6: Eu3+, Bi3+ fluorescent phosphor materials were synthesized using the high-temperature solid-state method. The luminescence of this phosphor is based on the 5D0→4F2 transition emission of Eu3+ ions, which occurs at 612 nm. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL) spectra, high-temperature fluorescence spectra, and fluorescence decay lifetimes to study the phase structure, optical properties, crystal structure, and chemical purity of the samples. The performance of the single-doped phosphor was significantly improved by the addition of Bi3+ sensitizer. The luminescence intensity increased by nearly 100% compared to Ca2GdSbO6: Eu3+ phosphor, with a quantum efficiency increase of 124%. The thermal quenching activation energy was found to be 0.299 eV, and the luminescence intensity remained at 70.3% of room temperature at 453 K. These results indicate that the co-doping of Bi3+ has a modulation and enhancement effect on the luminescence of Ca2GdSbO6: Eu3+ red phosphor, showing great potential for application in near-ultraviolet-excited white LED devices.

4.
Food Chem X ; 22: 101383, 2024 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-38665625

RESUMO

Pumpkin, nutritious vegetable, is renowned for its extended shelf life. In this study, seven pumpkin cultivars from Cucurbita moschata and Cucurbita maxima were comparatively characterized for 25 physiochemical quality factors, starch granule structures, antioxidant activity, and correlations at 0-60 days of postharvest (dop). The findings revealed that sucrose and carotenoid contents increased in C. moschata, while they initially increased and then decreased in C. maxima. Additionally, acidity, primarily driven by malic acid, decreased in C. maxima but increased in C. maxima. The starch content of C. moschata and C. maxima reached its maximum value at 30 dop and 20 dop, respectively. The DPPH radical scavenging activity correlated with the carotenoid content in both pumpkin species. Conclusively, C. moschata demonstrated improved nutritional and quality at 20-30 dop, while C. maxima exhibited higher commercial suitability at 10-20 dop. The findings suggested that pumpkin storage was crucial for quality improvement.

5.
ACS Appl Mater Interfaces ; 16(13): 16601-16611, 2024 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-38502203

RESUMO

Carbon Quantum dots (CQDs) are widely studied because of their good optical and electronic characteristics and because they can easily generate photocarriers. Nitrogen-doped CQDs (NCQDs) may exhibit improved hydrophilic, optical, and electron-transfer properties, which are conducive to photocatalytic hydrogen evolution. In this paper, NCQD-modified ZnS catalysts were successfully prepared. Under the irradiation of the full spectrum, the H2 evolution rate of the optimal catalyst 0.25 wt % NCQDs/ZnS achieves 5.70 mmol g-1 h-1, which is 11.88, 43.84, and 5.14 times the values of ZnS (0.48 mmol g-1 h-1), NCQDs (0.13 mmol g-1 h-1), and CQDs/ZnS (1.11 mmol g-1 h-1), respectively. Furthermore, it shows good stability, indicating that the modification of NCQDs prevents the photocorrosion and oxidation of ZnS. The enhanced performance is due to NCQD loading, which promotes the separation of photogenerated carriers, optimizes the structures, and increases the specific surface area. This work highlights the fact that NCQD-modified ZnS may afford a new strategy to synthesize ZnS-based photocatalysts with enhanced H2 production performance.

6.
BMC Plant Biol ; 24(1): 90, 2024 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-38317069

RESUMO

BACKGROUND: Photoperiod, or the length of the day, has a significant impact on the flowering and sex differentiation of photoperiod-sensitive crops. The "miben" pumpkin (the main type of Cucurbita moschata Duch.) is well-known for its high yield and strong disease resistance. However, its cultivation has been limited due to its sensitivity to photoperiod. This sensitivity imposes challenges on its widespread cultivation and may result in suboptimal yields in regions with specific daylength conditions. As a consequence, efforts are being made to explore potential strategies or breeding techniques to enhance its adaptability to a broader range of photoperiods, thus unlocking its full cultivation potential and further promoting its valuable traits in agriculture. RESULTS: This study aimed to identify photoperiod-insensitive germplasm exhibiting no difference in sex differentiation under different day-length conditions. The investigation involved a phenotypic analysis of photoperiod-sensitive (PPS) and photoperiod-insensitive (PPIS) pumpkin materials exposed to different day lengths, including long days (LDs) and short days (SDs). The results revealed that female flower differentiation was significantly inhibited in PPS_LD, while no differences were observed in the other three groups (PPS_SD, PPIS_LD, and PPIS_SD). Transcriptome analysis was carried out for these four groups to explore the main-effect genes of sex differentiation responsive to photoperiod. The main-effect gene subclusters were identified based on the principal component and hierarchical cluster analyses. Further, functional annotations and enrichment analysis revealed significant upregulation of photoreceptors (CmCRY1, F-box/kelch-repeat protein), circadian rhythm-related genes (CmGI, CmPRR9, etc.), and CONSTANS (CO) in PPS_LD. Conversely, a significant downregulation was observed in most Nuclear Factor Y (NF-Y) transcription factors. Regarding the gibberellic acid (GA) signal transduction pathway, positive regulators of GA signaling (CmSCL3, CmSCL13, and so forth) displayed higher expression levels, while the negative regulators of GA signaling, CmGAI, exhibited lower expression levels in PPS_LD. Notably, this effect was not observed in the synthetic pathway genes. Furthermore, genes associated with ethylene synthesis and signal transduction (CmACO3, CmACO1, CmERF118, CmERF118-like1,2, CmWIN1-like, and CmRAP2-7-like) showed significant downregulation. CONCLUSIONS: This study offered a crucial theoretical and genetic basis for understanding how photoperiod influences the mechanism of female flower differentiation in pumpkins.


Assuntos
Cucurbita , Cucurbita/genética , Fotoperíodo , Inibidores da Bomba de Prótons/metabolismo , Diferenciação Sexual , Melhoramento Vegetal , Perfilação da Expressão Gênica , Flores/metabolismo , Regulação da Expressão Gênica de Plantas
7.
Food Chem ; 441: 138334, 2024 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-38185051

RESUMO

The optical properties [absorption coefficient (µa) and reduced scattering coefficient (µs')] and internal quality [firmness (FI), moisture content (MC), and soluble solids content (SSC)] of stored potatoes at 25 °C were determined, along with ultrastructure observation. Potato tissue ultrastructure changed significantly with storage time, exhibiting enhanced scattering properties and a monotonic increase in µs'. The µa spectra showed significant correlations with MC and SSC, while the µs' spectra were more strongly correlated with FI. The competitive adaptive reweighted sampling (CARS) algorithm improved the prediction accuracy for partial least squares regression (PLSR) and support vector regression (SVR) models. The best predictions were 1st-Derivative-µs'-FI-PLSR (RP = 0.897, RMSEP = 0.036 N, RPD = 2.262), SG-µa -MC-SVR (RP = 0.886, RMSEP = 0.438 %, RPD = 2.157), and Raw-µa -SSC-SVR (RP = 0.873, RMSEP = 0.137 %, RPD = 2.050). These results demonstrate the potential for predicting internal quality using potato's optical properties.


Assuntos
Solanum tuberosum , Espectroscopia de Luz Próxima ao Infravermelho , Análise dos Mínimos Quadrados , Algoritmos
8.
Talanta ; 269: 125471, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38061203

RESUMO

Gold nanoparticles (AuNPs)@N-(4-aminobutyl)-N-ethylisoluminol (ABEI)@Titanium dioxide nanorods (TiO2NRs) were used as sensing materials to produce a unique encapsulated nanostructure aptasensor for the detection of acetamiprid residues in this work. ABEI, an analog of luminol, was extensively used as an electrochemiluminescence (ECL) reagent. The ECL mechanism of ABEI- hydrogen peroxide (H2O2) system had connections to a number of oxygen-centered free radicals. TiO2NRs improved ECL response with high electron transfer and a specific surface area. AuNPs were easy to biolabel and could catalyze H2O2 to enhance ECL signal. AuNPs were wrapped around TiO2NRs by utilizing the reduction property of ABEI to form wrapped modified nanomaterials. The sulfhydryl-modified aptamer bound to the nanomaterial by forming gold-sulfur (Au-S) bonds. The aptamer selectively bound to its target with the addition of acetamiprid, which caused a considerable decrease in ECL intensity and enabled quantitative detection of acetamiprid. The aptasensor showed good stability, repeatability and specificity with a broad detection range (1×10-2-1×103 nM) and a lower limit of detection (3 pM) for acetamiprid residues in vegetables. Overall, this aptasensor presents a simple and highly sensitive method for ECL detecting acetamiprid, with potential applications in vegetable safety monitoring.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Nanopartículas Metálicas , Nanotubos , Ouro/química , Verduras , Nanopartículas Metálicas/química , Limite de Detecção , Peróxido de Hidrogênio/química , Medições Luminescentes/métodos , Técnicas Biossensoriais/métodos , Luminol/química , Aptâmeros de Nucleotídeos/química , Técnicas Eletroquímicas/métodos
9.
Microbiol Spectr ; 12(1): e0203023, 2024 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-38032193

RESUMO

IMPORTANCE: Tigecycline, a glycecycline antibiotic with broad-spectrum activity against almost all Gram-positive and Gram-negative bacteria, is a highly concerned "last-resort" antibiotic. In addition to plasmid-hosted mobile tet(X) conferring high-level resistance to tigecycline, there are many reports suggesting increased expression of AcrAB-TolC efflux pump leads to tigecycline non-susceptibility. However, the role of mutations in AcrAB-TolC on tigecycline resistance has not been identified. This study reports a novel T188A mutation of the AcrA subunit of AcrAB-TolC complex in a clinical tigecycline-resistant Klebsiella pneumoniae strain and reveals the role of AcrA mutation on tigecycline resistance in K. pneumoniae. High prevalence of A188 type AcrA in hypervirulent multidrug-resistant K. pneumoniae indicates that mutations of the AcrAB-TolC complex may play a larger role in determining bacterial pathogenesis and antibiotic susceptibility than previously expected.


Assuntos
Antibacterianos , Infecções por Klebsiella , Humanos , Tigeciclina/farmacologia , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/metabolismo , Minociclina/farmacologia , Aminoácidos , Bactérias Gram-Negativas/metabolismo , Bactérias Gram-Positivas/metabolismo , Mutação , Testes de Sensibilidade Microbiana , Infecções por Klebsiella/microbiologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Farmacorresistência Bacteriana/genética
10.
ACS Biomater Sci Eng ; 10(1): 326-337, 2024 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-38147691

RESUMO

As potential degradable biomaterials, magnesium (Mg) alloys have development prospects in the field of orthopedic load-bearing, whereas the clinical application has encountered a bottleneck due to a series of problems caused by its rapid corrosion. In this study, strontium-substituted calcium phosphate (CaP) coatings with different structures were prepared on the surface of the Mg matrix by a simple one-step electrodeposition method at different temperatures, which enhanced the poor corrosion resistance of the Mg matrix. The coated sample prepared at 65 °C reduced the corrosion current density by 3 orders of magnitude and increased the impedance by nearly 2 orders of magnitude compared with bare Mg alloy, thanks to its dense fibrous structure similar to that of natural bones. Although the coating composition varies with different preparation temperatures, CaP, as an inorganic component similar to natural bone, has good cytocompatibility. Doping the right amount of strontium, which is a trace element in human bones, is beneficial to stimulate osteoblast differentiation, inhibit the activity of osteoclasts, and induce the formation of bone tissues. This provides a new option for modifying the Mg alloy with CaP coatings as a base.


Assuntos
Cálcio , Magnésio , Humanos , Cálcio/química , Magnésio/farmacologia , Magnésio/química , Corrosão , Materiais Revestidos Biocompatíveis/farmacologia , Materiais Revestidos Biocompatíveis/química , Temperatura , Galvanoplastia , Ligas/farmacologia , Ligas/química , Estrôncio/farmacologia , Fosfatos de Cálcio/farmacologia , Fosfatos de Cálcio/química
11.
Anal Methods ; 15(31): 3854-3862, 2023 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-37496451

RESUMO

The quantitative determination of the soluble solid content (SSC) of potatoes using NIR spectroscopy is useful for predicting the internal and external quality of potato products, especially fried products. In this study, the effect of peel on the partial least squares regression (PLSR) quantitative prediction of potato SSC was investigated by transmission and reflection. The results show that the variable sorting for normalization (VSN) pre-processing method improved model accuracy. Additive multiplicative scattering effects and intensity drift interference of the peels were reduced. The model accuracy reached a correlation coefficient of prediction (RP) of 0.85. The selection algorithm using variable combination population analysis and iterative retention of information variables (VCPA-IRIV) demonstrated that peel increases unnecessary information. When the effect of irrelevant variables was reduced, the results reached RP = 0.88 and the root mean square error of prediction (RMSEP) = 0.25 in the transmission mode was close to that of the full-wavelength peeled PLSR model (RP = 0.89 and RMSEP = 0.25). This indicates that the use of the combined algorithm (VSN-VCPA-IRIV) reduces the effect of the peel and enables samples with a peel to still be predicted accurately in the full-wavelength model. It also improves detection efficiency through the extraction of the necessary variables and optimizes the stability and accuracy of the model.

12.
ACS Biomater Sci Eng ; 9(6): 3227-3238, 2023 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-37252838

RESUMO

Magnesium (Mg) alloys, a degradable material, have been studied for medical applications due to their excellent mechanical and chemical properties. However, their applications are limited by rapid corrosion. In this work, stearic acid and sodium stearate were used to treat the silane-induced calcium phosphate dihydrate coating to improve its protection for the Mg alloy further without changing the bone-like structure of calcium phosphate. The different effects of stearic acid treatment and sodium stearate treatment were compared. Electrochemical test and immersion test results confirmed that the corrosion resistance of the stearic acid-treated composite coating was greatly enhanced with a reduced corrosion current density by 3 orders of magnitude and hydrogen evolution reduced to 1/25 after 14 days. The stearic acid-treated coating also exhibited improved in vitro biocompatibility corroborated by promoted cell viability and better cell morphology.


Assuntos
Ligas , Magnésio , Magnésio/farmacologia , Magnésio/química , Ligas/farmacologia , Ligas/química , Corrosão , Materiais Revestidos Biocompatíveis/farmacologia , Materiais Revestidos Biocompatíveis/química , Biomimética , Fosfatos de Cálcio/farmacologia , Fosfatos de Cálcio/química
13.
Commun Biol ; 6(1): 219, 2023 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-36828846

RESUMO

The Arabidopsis H3K9 methyltransferases KRYPTONITE/SUPPRESSOR OF VARIEGATION 3-9 HOMOLOG 4 (KYP/SUVH4), SUVH5 and SUVH6 are redundantly involved in silencing of transposable elements (TEs). Our recent study indicated that KYP/SUVH5/6 can directly interact with the histone deacetylase HDA6 to synergistically regulate TE expression. However, the function of KYP/SUVH5/6 in plant development is still unclear. The transcriptional factors ASYMMETRIC LEAVES1 (AS1) and AS2 form a transcription complex, which is involved in leaf development by repressing the homeobox genes KNOTTED-LIKE FROM ARABIDOPSIS THALIANA 1 (KNAT1) and KNAT2. In this study, we found that KYP and SUVH5/6 directly interact with AS1-AS2 to repress KNAT1 and KNAT2 by altering histone H3 acetylation and H3K9 dimethylation levels. In addition, KYP can directly target the promoters of KNAT1 and KNAT2, and the binding of KYP depends on AS1. Furthermore, the genome-wide occupancy profile of KYP indicated that KYP is enriched in the promoter regions of coding genes, and the binding of KYP is positively correlated with that of AS1 and HDA6. Together, these results indicate that Arabidopsis H3K9 methyltransferases KYP/SUVH5/6 are involved in leaf development by interacting with AS1-AS2 to alter histone H3 acetylation and H3K9 dimethylation from KNAT1 and KNAT2 loci.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/genética , Metiltransferases/metabolismo , Histonas/metabolismo , Lisina/metabolismo , Folhas de Planta , Proteínas de Homeodomínio/genética , Proteínas de Arabidopsis/metabolismo , Histona Desacetilases/metabolismo
14.
Phytochemistry ; 207: 113582, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36596436

RESUMO

Alnus cremastogyne Burkill (Betulaceae), an actinorhizal plant, can enter a mutualistic symbiosis with Frankia species that leads to the formation of nitrogen fixing root nodules. Some primary metabolites (carbohydrates, dicarboxylic acids, amino acids, citrulline and amides) involved in carbon and nitrogen metabolism in actinorhizal nodules have been identified, while specialized metabolites in A. cremastogyne root nodules are yet to be characterized. In this study, we isolated and identified three undescribed 3-pentanol glycosides, i.e., 3-pentyl α-l-arabinofuranosyl-(1''→6')-ß-d-glucopyranoside, 3-pentyl α-l-rhamnopyranosyl-(1''→6')-ß-d-glucopyranoside, and 3-pentyl 6'-(3-hydroxy3-methylglutaryl)-ß-d-glucopyranoside, as well as seventeen known compounds from A. cremastogyne root nodules. 3-Pentanol glycosides are abundantly distributed in root nodules, while they are distributed in stems, roots, leaves and fruits at low/zero levels. A. cremastogyne plants treated by root nodule suspension emit 3-pentanol. This study enriches the knowledge about specialized metabolites in the actinorhizal host, and provides preliminarily information on the signal exchange in the actinorhizal symbiosis between A. cremastogyne and Frankia.


Assuntos
Alnus , Frankia , Pentanóis/metabolismo , Glicosídeos/metabolismo , Raízes de Plantas , Frankia/metabolismo , Simbiose , Plantas , Nitrogênio/metabolismo , Fixação de Nitrogênio , Nódulos Radiculares de Plantas
16.
ACS Appl Bio Mater ; 5(4): 1528-1537, 2022 04 18.
Artigo em Inglês | MEDLINE | ID: mdl-35312270

RESUMO

Magnesium (Mg) and its alloys have exhibited great potential for orthopedic applications; however, their poor corrosion resistance and potential cytotoxicity have hindered their further clinical applications. In this study, we prepared a calcium phosphate (Ca-P) coating with a micro-nanofibrous porous structure on the Mg alloy surface by a chemical conversion method. The morphology, composition, and corrosion performance of the coatings were investigated by scanning electron microscope (SEM), energy-dispersive spectrometer (EDS), X-ray diffraction (XRD), immersion tests, and electrochemical measurements. The effects of the preparation temperature of the Ca-P coatings were analyzed, and the results confirmed that the coating obtained at 60 °C had the densest structure and the best corrosion resistance. In addition, a systematic investigation into cell viability, ALP activity, and cell morphology confirmed that the Ca-P coating had excellent biocompatibility, which could effectively promote the proliferation, differentiation, and adhesion of osteoblasts. Hence, the Ca-P coating demonstrates great potential in the field of biodegradable Mg-based orthopedic implant materials.


Assuntos
Ligas , Nanofibras , Ligas/química , Fosfatos de Cálcio/química , Materiais Revestidos Biocompatíveis/química , Corrosão , Magnésio/farmacologia , Porosidade
17.
J Exp Bot ; 73(3): 835-847, 2022 01 27.
Artigo em Inglês | MEDLINE | ID: mdl-34545936

RESUMO

BRAHMA (BRM) is the ATPase of the SWItch/Sucrose Non-Fermentable (SWI/SNF) chromatin remodelling complex, which is indispensable for transcriptional inhibition and activation, associated with vegetative and reproductive development in Arabidopsis thaliana. Here, we show that BRM directly binds to the chromatin of SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1), which integrates multiple flowering signals to regulate floral transition, leading to flowering. In addition, genetic and molecular analysis showed that BRM interacts with GNC (GATA, NITRATE-INDUCIBLE, CARBON METABOLISM INVOLVED), a GATA transcription factor that represses flowering by directly repressing SOC1 expression. Furthermore, BRM is recruited by GNC to directly bind to the chromatin of SOC1. The transcript level of SOC1 is elevated in brm-3, gnc, and brm-3/gnc mutants, which is associated with increased histone H3 lysine 4 tri-methylation (H3K4Me3) but decreased DNA methylation. Taken together, our results indicate that BRM associates with GNC to regulate SOC1 expression and flowering time.


Assuntos
Adenosina Trifosfatases , Proteínas de Arabidopsis , Arabidopsis , Montagem e Desmontagem da Cromatina , Fatores de Transcrição , Adenosina Trifosfatases/genética , Adenosina Trifosfatases/metabolismo , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Fatores de Transcrição GATA/genética , Fatores de Transcrição GATA/metabolismo , Regulação da Expressão Gênica de Plantas , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
18.
Plant J ; 109(4): 831-843, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34807487

RESUMO

MULTICOPY SUPPRESSOR OF IRA1 (MSI1) is a conserved subunit of Polycomb Repressive Complex 2 (PRC2), which mediates gene silencing by histone H3 lysine 27 trimethylation (H3K27Me3). Here, we demonstrated that MSI1 interacts with the RPD3-like histone deacetylase HDA6 both in vitro and in vivo. MSI1 and HDA6 are involved in flowering and repress the expression of FLC, MAF4, and MAF5 by removing H3K9 acetylation but adding H3K27Me3. Chromatin immunoprecipitation analysis showed that HDA6 and MSI1 interdependently bind to the chromatin of FLC, MAF4, and MAF5. Furthermore, H3K9 deacetylation mediated by HDA6 is dependent on MSI1, while H3K27Me3 mediated by PRC2 containing MSI1 is also dependent on HDA6. Taken together, these data indicate that MSI1 and HDA6 act interdependently to repress the expression of FLC, MAF4, and MAF5 through histone modifications. Our findings reveal that the HDA6-MSI1 module mediates the interaction between histone H3 deacetylation and H3K27Me3 to repress gene expression involved in flowering time control.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Cromatina/metabolismo , Flores/metabolismo , Histona Desacetilases/metabolismo , Acetilação , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Imunoprecipitação da Cromatina , Flores/genética , Regulação da Expressão Gênica de Plantas , Inativação Gênica , Histona Desacetilases/genética , Histonas/metabolismo , Proteínas de Domínio MADS/metabolismo , Complexo Repressor Polycomb 2/genética , Complexo Repressor Polycomb 2/metabolismo , Proteínas Repressoras/metabolismo
19.
Cells ; 10(11)2021 11 03.
Artigo em Inglês | MEDLINE | ID: mdl-34831226

RESUMO

The changes in histone acetylation mediated by histone deacetylases (HDAC) play a crucial role in plant development and response to environmental changes. Mammalian HDACs are regulated by post-translational modifications (PTM), such as phosphorylation, acetylation, ubiquitination and small ubiquitin-like modifier (SUMO) modification (SUMOylation), which affect enzymatic activity and transcriptional repression. Whether PTMs of plant HDACs alter their functions are largely unknown. In this study, we demonstrated that the Arabidopsis SUMO E3 ligase SAP AND MIZ1 DOMAIN-CONTAINING LIGASE1 (SIZ1) interacts with HISTONE DEACETYLASE 6 (HDA6) both in vitro and in vivo. Biochemical analyses indicated that HDA6 is not modified by SUMO1. Overexpression of HDA6 in siz1-3 background results in a decreased level of histone H3 acetylation, indicating that the activity of HDA6 is increased in siz1-3 plants. Chromatin immunoprecipitation (ChIP) assays showed that SIZ1 represses HDA6 binding to its target genes FLOWERING LOCUS C (FLC) and MADS AFFECTING FLOWERING 4 (MAF4), resulting in the upregulation of FLC and MAF4 by increasing the level of histone H3 acetylation. Together, these findings indicate that the Arabidopsis SUMO E3 ligase SIZ1 interacts with HDA6 and negatively regulates HDA6 function.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiologia , Flores/fisiologia , Histona Desacetilases/metabolismo , Ligases/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Flores/genética , Regulação da Expressão Gênica de Plantas , Histona Desacetilases/genética , Ligases/genética , Mutação/genética , Ligação Proteica
20.
J Mech Behav Biomed Mater ; 123: 104759, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34365100

RESUMO

Magnesium (Mg)-based composites, as biomaterials, have attracted widespread attention due to their adjustable mechanical properties like elastic modulus, ductility, ultimate tensile strength, and corrosion resistance. In this study, hydroxyapatite (HA) reinforced ZK61 Mg-matrix composites were prepared by powder metallurgy and hot extrusion methods. The influence of the content of HA (10 wt%, 20 wt%, and 30 wt%) on the microstructure, density, mechanical properties, corrosion property and biocompatibility were investigated. The results showed that the density and yield strength of the composites match those of natural bone. Moreover, the composite with 10 % HA (ZK61-10HA) exhibited the best corrosion resistance, as determined by the electrochemical measurement and immersion test in simulated body fluid (SBF) at 37 °C. In addition, the ZK61-10HA composite significantly enhanced the cell viability (≥78 %) compared with ZK61 alloy in vitro testing. It is demonstrated that the mechanical properties, corrosion resistance and biocompatibility of Mg alloy can be effectively controlled by adjusting the content of HA, which suggested that the ZK61-HA composites were promising candidates for degradable implant materials.


Assuntos
Durapatita , Magnésio , Ligas , Materiais Biocompatíveis/farmacologia , Corrosão , Teste de Materiais
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