Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 52
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
País de afiliação
Intervalo de ano de publicação
1.
BMC Biol ; 21(1): 134, 2023 06 06.
Artigo em Inglês | MEDLINE | ID: mdl-37280593

RESUMO

BACKGROUND: Sapria himalayana (Rafflesiaceae) is an endoparasitic plant characterized by a greatly reduced vegetative body and giant flowers; however, the mechanisms underlying its special lifestyle and greatly altered plant form remain unknown. To illustrate the evolution and adaptation of S. himalayasna, we report its de novo assembled genome and key insights into the molecular basis of its floral development, flowering time, fatty acid biosynthesis, and defense responses. RESULTS: The genome of S. himalayana is ~ 1.92 Gb with 13,670 protein-coding genes, indicating remarkable gene loss (~ 54%), especially genes involved in photosynthesis, plant body, nutrients, and defense response. Genes specifying floral organ identity and controlling organ size were identified in S. himalayana and Rafflesia cantleyi, and showed analogous spatiotemporal expression patterns in both plant species. Although the plastid genome had been lost, plastids likely biosynthesize essential fatty acids and amino acids (aromatic amino acids and lysine). A set of credible and functional horizontal gene transfer (HGT) events (involving genes and mRNAs) were identified in the nuclear and mitochondrial genomes of S. himalayana, most of which were under purifying selection. Convergent HGTs in Cuscuta, Orobanchaceae, and S. himalayana were mainly expressed at the parasite-host interface. Together, these results suggest that HGTs act as a bridge between the parasite and host, assisting the parasite in acquiring nutrients from the host. CONCLUSIONS: Our results provide new insights into the flower development process and endoparasitic lifestyle of Rafflesiaceae plants. The amount of gene loss in S. himalayana is consistent with the degree of reduction in its body plan. HGT events are common among endoparasites and play an important role in their lifestyle adaptation.


Assuntos
Genoma Mitocondrial , Transferência Genética Horizontal , Plantas/genética , Flores/genética , Filogenia
2.
Microb Cell Fact ; 22(1): 52, 2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36918882

RESUMO

BACKGROUND: Thraustochytrids accumulate lipids with a high content of docosahexaenoic acid (DHA). Although their growth and DHA content are significantly affected by the dissolved oxygen (DO) supply, the role of DO on the transcriptional regulation of metabolism and accumulation of intracellular metabolites remains poorly understood. Here we investigate the effects of three different DO supply conditions (10%, 30%, and 50%) on the fed-batch culture of the Aurantiochytrium PKU#Mn16 strain to mainly reveal the differential gene expressions and metabolite profiles. RESULTS: While the supply of 10% DO significantly reduced the rates of biomass and DHA production in the early stages of fermentation, it achieved the highest amounts of biomass (56.7 g/L) and DHA (6.0 g/L) on prolonged fermentation. The transcriptome analyses of the early stage (24 h) of fermentation revealed several genes involved in the central carbon, amino acid, and fatty acid metabolism, which were significantly downregulated at a 10% DO level. The comparative metabolomics results revealed the accumulation of several long-chain fatty acids, amino acids, and other metabolites, supporting the transcriptional regulation under the influence of a low oxygen supply condition. In addition, certain genes involved in antioxidative systems were downregulated under 10% DO level, suggesting a lesser generation of reactive oxygen species that lead to oxidative damage and fatty acid oxidation. CONCLUSIONS: The findings of this study suggest that despite the slow growth and metabolism in the early stage of fermentation of Aurantiochytrium sp. PKU#Mn16, a constant supply of low dissolved oxygen can yield biomass and DHA content better than that with high oxygen supply conditions. The critical information gained in this study will help to further improve DHA production through bioprocess engineering strategies.


Assuntos
Ácidos Docosa-Hexaenoicos , Estramenópilas , Ácidos Docosa-Hexaenoicos/metabolismo , Fermentação , Ácidos Graxos/metabolismo , Metabolismo dos Lipídeos , Estramenópilas/genética , Oxigênio/metabolismo
3.
Ecotoxicol Environ Saf ; 263: 115282, 2023 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-37494734

RESUMO

Nearly all modern life depends on artificial light; however, it does cause health problems. With certain restrictions of artificial light emitting technology, the influence of the light spectrum is inevitable. The most remarkable problem is its overload in the short wavelength component. Short wavelength artificial light has a wide range of influences from ocular development to mental problems. The visual neuronal pathway, as the primary light-sensing structure, may contain the fundamental mechanism of all light-induced abnormalities. However, how the artificial light spectrum shapes the visual neuronal pathway during development in mammals is poorly understood. We placed C57BL/6 mice in three different spectrum environments (full-spectrum white light: 400-750 nm; violet light: 400 ± 20 nm; green light: 510 ± 20 nm) beginning at eye opening, with a fixed light time of 7:00-19:00. During development, we assessed the ocular axial dimension, visual function and retinal neurons. After two weeks under short wavelength conditions, the ocular axial length (AL), anterior chamber depth (ACD) and length of lens thickness, real vitreous chamber depth and retinal thickness (LLVR) were shorter, visual acuity (VA) decreased, and retinal electrical activity was impaired. The density of S-cones in the dorsal and ventral retinas both decreased after one week under short wavelength conditions. In the ventral retina, it increased after three weeks. Retinal ganglion cell (RGC) density and axon thickness were not influenced; however, the axonal terminals in the lateral geniculate nucleus (LGN) were less clustered and sparse. Amacrine cells (ACs) were significantly more activated. Green light has few effects. The KEGG and GO enrichment analyses showed that many genes related to neural circuitry, synaptic formation and neurotransmitter function were differentially expressed in the short wavelength light group. In conclusion, exposure to short wavelength artificial light in the early stage of vision-dependent development in mice delayed the development of the visual pathway. The axon terminus structure and neurotransmitter function may be the major suffering.


Assuntos
Retina , Células Fotorreceptoras Retinianas Cones , Animais , Camundongos , Camundongos Endogâmicos C57BL , Retina/metabolismo , Células Fotorreceptoras Retinianas Cones/fisiologia , Células Ganglionares da Retina/fisiologia , Vias Neurais , Mamíferos
4.
Drug Chem Toxicol ; 46(2): 369-379, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35172660

RESUMO

Cisplatin is a widely used chemotherapeutic agent. However, its clinical application remains limited due to the high incidence of severe ototoxicity. It has been reported that the unfolded protein response (UPR) is involved in cisplatin-induced ototoxicity. However, the specific mechanism underlying its effect remains unclear. Therefore, the present study aimed to explore the sequential changes in the key UPR signaling branch and its potential pro-apoptotic role in cisplatin-induced ototoxicity. The hair cell-like OC-1 cells were treated with cisplatin for different periods and then the expression levels of the UPR- and apoptosis-related proteins were determined. The results showed that the apoptotic rate of cells was gradually increased with prolonged cisplatin treatment. Furthermore, the sequential changes in three UPR signaling branches were evaluated. The expression levels of activating transcription factor 4 (ATF4) and C/EBP homologous protein (CHOP) were gradually increased with up to 12 h of cisplatin treatment. The aforementioned expression profile was consistent with that observed for the apoptosis-related proteins. Subsequently, the proportion of apoptotic cells was notably decreased in CHOP-silenced hair cell-like OC-1 cells following treatment with cisplatin. Moreover, we found significant hair cells loss and a higher level of CHOP in cisplatin-treated cochlear explants in a time-dependent manner. Overall, the present study demonstrated that the protein kinase RNA­like endoplasmic reticulum kinase (PERK)/ATF4/CHOP signaling branch could play an important role in cisplatin-induced cell apoptosis. Furthermore, the current study suggested that CHOP may be considered as a promising therapeutic target for cisplatin-induced ototoxicity.


Assuntos
Cisplatino , Ototoxicidade , Humanos , Cisplatino/toxicidade , Fator 4 Ativador da Transcrição/genética , Fator 4 Ativador da Transcrição/metabolismo , Fator 4 Ativador da Transcrição/farmacologia , Estresse do Retículo Endoplasmático/fisiologia , RNA/metabolismo , RNA/farmacologia , Ototoxicidade/metabolismo , Resposta a Proteínas não Dobradas , Retículo Endoplasmático/metabolismo
5.
BMC Plant Biol ; 22(1): 448, 2022 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-36123622

RESUMO

BACKGROUND: Plastomes of heterotrophic plants have been greatly altered in structure and gene content, owing to the relaxation of selection on photosynthesis-related genes. The orchid tribe Gastrodieae is the largest and probably the oldest mycoheterotrophic clade of the extant family Orchidaceae. To characterize plastome evolution across members of this key important mycoheterotrophic lineage, we sequenced and analyzed the plastomes of eleven Gastrodieae members, including representative species of two genera, as well as members of the sister group Nervilieae. RESULTS: The plastomes of Gastrodieae members contain 20 protein-coding, four rRNA and five tRNA genes. Evolutionary analysis indicated that all rrn genes were transferred laterally and together, forming an rrn block in the plastomes of Gastrodieae. The plastome GC content of Gastrodia species ranged from 23.10% (G. flexistyla) to 25.79% (G. javanica). The plastome of Didymoplexis pallens contains two copies each of ycf1 and ycf2. The synonymous and nonsynonymous substitution rates were very high in the plastomes of Gastrodieae among mycoheterotrophic species in Orchidaceae and varied between genes. CONCLUSIONS: The plastomes of Gastrodieae are greatly reduced and characterized by low GC content, rrn block formation, lineage-specific reconfiguration and gene content, which might be positively selected. Overall, the plastomes of Gastrodieae not only serve as an excellent model for illustrating the evolution of plastomes but also provide new insights into plastome evolution in parasitic plants.


Assuntos
Genomas de Plastídeos , Orchidaceae , Processos Heterotróficos/genética , Orchidaceae/genética , Fotossíntese/genética
6.
BMC Ophthalmol ; 22(1): 456, 2022 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-36443719

RESUMO

BACKGROUND: Pathogenesis of posterior capsular opacification (PCO) was related to pathological epithelial-mesenchymal transition (EMT) of lens epithelial cells (LECs). It has been reported that blue light could have an effect on EMT. This study aims to elucidate the role and potential mechanism of autophagy in EMT after blue light exposure in LECs. METHODS: HLE-B3 cells were treated with TGF-ß2 with different concentration and time to induce EMT as a model of PCO in vitro. Cells were exposed to blue light with or without TGF-ß2. The expression levels of EMT-associated markers were analyzed by qRT-PCR, western blotting and cell migration ability was determined by transwell migration assay and wound healing assay. The expressions of autophagy-related proteins were analyzed by western blotting, immunofluorescence and transmission electron microscopy. Rapamycin and chloroquine were utilized in cells for autophagy activation and inhibition. RESULTS: TGF-ß2 induced autophagy activation during EMT progression in HLE-B3 cells in a dose- and time-dependent manner. Blue light exposure inhibited TGF-ß2-induced EMT characterized by inhibited expression of EMT related markers and reduced migration capacity. Meanwhile, blue light exposure impaired autophagy activated by TGF-ß2. Furthermore, Autophagy activation with rapamycin rescued EMT attenuated by blue light. Autophagy inhibition with chloroquine reduced TGF-ß2-induced EMT in HLE-B3 cells. CONCLUSION: Blue light exposure had inhibited effects on TGF-ß2-induced EMT in LECs through autophagy impairment, which provides a new insight on prevention and treatment of PCO.


Assuntos
Transição Epitelial-Mesenquimal , Fator de Crescimento Transformador beta2 , Humanos , Autofagia , Cloroquina , Células Epiteliais , Sirolimo , Fator de Crescimento Transformador beta2/farmacologia , Luz
7.
BMC Ophthalmol ; 22(1): 451, 2022 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-36418970

RESUMO

BACKGROUND: Changes in the retina and choroid blood vessels are regularly observed in myopia. However, if the retinal glial cells, which directly contact blood vessels, play a role in mammalian myopia is unknown. We aimed to explore the potential role and mechanism of retinal glial cells in form deprived myopia. METHODS: We adapted the mice form-deprivation myopia model by covering the right eye and left the left eye open for control, measured the ocular structure with anterior segment optical coherence tomography, evaluated changes in the morphology and distribution of retinal glial cells by fluorescence staining and western blotting; we also searched the online GEO databases to obtain relative gene lists and confirmed them in the form-deprivation myopia mouse retina at mRNA and protein level. RESULTS: Compared with the open eye, the ocular axial length (3.54 ± 0.006 mm v.s. 3.48 ± 0.004 mm, p = 0.027) and vitreous chamber depth (3.07 ± 0.005 mm v.s. 2.98 ± 0.006 mm, p = 0.007) in the covered eye became longer. Both glial fibrillary acidic protein and excitatory amino acid transporters 4 elevated. There were 12 common pathways in human myopia and anoxic astrocytes. The key proteins were also highly relevant to atropine target proteins. In mice, two common pathways were found in myopia and anoxic Müller cells. Seven main genes and four key proteins were significantly changed in the mice form-deprivation myopia retinas. CONCLUSION: Retinal astrocytes and Müller cells were activated in myopia. They may response to stimuli and secretory acting factors, and might be a valid target for atropine.


Assuntos
Células Ependimogliais , Miopia , Humanos , Camundongos , Animais , Astrócitos , Neuroglia , Atropina , Retina , Modelos Animais de Doenças , Hipóxia , Mamíferos
8.
Artigo em Inglês | MEDLINE | ID: mdl-35880484

RESUMO

A simple and efficient pH-mediated dispersive solid phase extraction (dSPE) based on terbium doped titanium dioxide nanoparticles (TiO2-Tb NPs) combined with high performance liquid chromatography (HPLC) has been firstly developed for the determination of quinolones (QNs) in various biological samples. The adsorption kinetics and isotherms were investigated to indicate that the kinetic and equilibrium adsorption were well-described by pseudo-second order kinetic and Henry, Langmuir isotherm model, respectively. The parameters influencing the extraction performance were systematically investigated. The QNs are transferred into TiO2-Tb NPs in the first step at pH = 6.0 and eluted into acidic aqueous phase at pH = 2.5 in the second step. Under the optimum extraction and determination conditions, a linearity range with the coefficient of determination (R2) from 0.9977 to 0.9991 were obtained in a range of 10-10,000 ng mL-1. The limits of detection (LODs) based on a signal-to-noise ratio of 3 were 3.3 ng mL-1. The recoveries of the three QNs in human urine, rabbit plasma and serum samples ranged from 69.3% to 117.6%, with standard deviations ranging from 2.4% to 9.9%. Therefore, this pH-mediated dSPE-HPLC method exhibited the advantages of remarkable sensitivity, ease of operation, rapidity, low cost and environmental friendliness.


Assuntos
Nanopartículas , Quinolonas , Adsorção , Animais , Cromatografia Líquida de Alta Pressão/métodos , Humanos , Concentração de Íons de Hidrogênio , Nanopartículas/química , Quinolonas/análise , Coelhos , Extração em Fase Sólida/métodos , Titânio
9.
BMC Ophthalmol ; 21(1): 88, 2021 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-33596849

RESUMO

BACKGROUND: Myopia is hypothesized to be influenced by environmental light conditions. For example, it has been shown that colour and temporal frequency of flickering light affect emmetropisation in animals. Considering the omnipresence of flickering light in our daily life, we decided to analyze the effect of colour flickers on variability of the accommodation response (VAR) in emmetropes and myopes. METHODS: We measured the dynamic accommodative responses of 19 emmetropic and 22 myopic adults using a Grand Seiko WAM-5500 open-field autorefractor. The subjects focused for more than 20 s on a black Snellen E target against three different backgrounds made up of three colour flicker combinations (red/green, red/blue and blue/green) and under five frequency conditions (0.20 Hz, 0.50 Hz, 1.00 Hz, 1.67 Hz, and 5.00 Hz). RESULTS: Flicker frequency and colour both had a significant effect on VAR. Lower frequencies were associated with larger variability. Colour had an effect only at low frequencies, and red/blue colour flicker resulted in the largest variability. The variability in myopes were larger than those in emmetropes. CONCLUSIONS: These findings support the hypothesis that further studies on the colour and temporal frequency of flickering light can lead to a better understanding of the development and progression of myopia.


Assuntos
Acomodação Ocular , Miopia , Adulto , Cor , Emetropia , Humanos , Acuidade Visual
10.
Am J Pathol ; 188(8): 1754-1767, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29803830

RESUMO

Myopia is a serious sight-compromising condition in which decreases in scleral biomechanical strength are associated with protease up-regulation resulting in thinning of its collagenous framework and changes in the extracellular matrix composition. Matrix metallopeptidase (MMP)-2 is one of the known proteases mediating these alterations. To determine whether MMP-2 up-regulation precedes myopia development, the direct effects of gain and loss in Mmp2 gene function were evaluated on refractive development and form deprivation myopia in mice. Four weeks after injecting an adeno-associated virus serotype 8 packaged Mmp2 overexpression vector (AAV8-Mmp2), scleral MMP-2 up-regulation was accompanied by significant myopia in a normal visual environment. In contrast, AAV8 packaging with shRNA targeting Mmp2 inhibited rises in MMP-2 expression induced by form deprivation by 54% and reduced myopia development by 23% compared with eyes injected with an irrelevant scrambled sequence. Because opposing changes in MMP-2 protein expression levels had corresponding effects on myopia progression, up-regulation of this protease contributes to inducing this condition. This notion of a cause-and-effect relationship between MMP-2 up-regulation and myopia development is supported by showing that form-deprived myopia development was attenuated by 27% in fibroblast-specific Mmp2 deletion (S100a4creMmp2fl/fl) mice relative to Cre-negative littermates (Mmp2fl/fl). Therefore, MMP-2 is a potential drug target for inhibiting myopia progression.


Assuntos
Modelos Animais de Doenças , Fibroblastos/patologia , Metaloproteinase 2 da Matriz/metabolismo , Miopia/patologia , Esclera/enzimologia , Animais , Progressão da Doença , Fibroblastos/enzimologia , Masculino , Metaloproteinase 2 da Matriz/genética , Camundongos , Camundongos Endogâmicos C57BL , Miopia/enzimologia , Miopia/genética , Regulação para Cima
11.
Neural Plast ; 2018: 9425725, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29849575

RESUMO

PTPRQ gene, encoding protein tyrosine phosphatase receptor Q, is essential for the normal maturation and function of hair bundle in the cochlea. Its mutations can cause the defects of stereocilia in hair cell, which lead to nonsyndromic sensorineural hearing loss. Using next-generation sequencing and Sanger sequencing method, we identified a novel compound heterozygous missense mutation, c.4472C>T p.T1491M (maternal allele) and c.1973T>C p.V658A (paternal allele), in PTPRQ gene. The two mutations are the first reported to be the cause of recessively inherited sensorineural hearing loss. Hearing loss levels and progression involved by PTPRQ mutations among the existing cases seem to be varied, and the relationship between genotypes and phenotypes is unclear. Our data here further prove the important role of PTPRQ in auditory function and provide more information for the further mechanism research of PTPRQ-related hearing loss.


Assuntos
Predisposição Genética para Doença , Perda Auditiva Neurossensorial/genética , Mutação de Sentido Incorreto , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/genética , Povo Asiático/genética , Pré-Escolar , China , Feminino , Genes Recessivos , Perda Auditiva Neurossensorial/congênito , Heterozigoto , Humanos , Proteínas Mutantes/química , Linhagem , Estrutura Terciária de Proteína , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/química
12.
Molecules ; 24(1)2018 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-30591670

RESUMO

A rapid and sensitive ionic liquid (IL) based headspace gas chromatography-mass spectrometry (HS-GC-MS) method was developed for analyzing volatile components in leaf, pericarp, and seed of Clausena lansium from different areas in Hainan Province, China. HS efficiencies were carefully investigated by using three ILs and water as matrix media. Extraction parameters, including equilibrium temperature, equilibrium time, and stirring rate had been evaluated and optimized by using an orthogonal design with OA9(3³) table. Under the optimized condition of IL-based HS-GC-MS, only 100 mg of sample and 2 mL of [Bmim][BF4] were needed to comprehensively and accurately analyze the volatile components in Clausena lansium. By utilizing a cluster analysis, six clusters were obtained for ninety components. This method was simpler, more rapid, and more sensitive when compared with previously reported methods for analyzing and identifying volatile components in Clausena lansium. The results may provide a theoretical basis for further exploitation of Clausena lansium.


Assuntos
Clausena/química , Cromatografia Gasosa-Espectrometria de Massas/métodos , Líquidos Iônicos/química , Compostos Orgânicos Voláteis/análise , Análise de Variância , Filogenia , Folhas de Planta/química , Sementes/química
13.
Electrophoresis ; 35(4): 474-81, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24165973

RESUMO

In this study, a method of pretreatment and speciation analysis of mercury by dispersive liquid-liquid microextraction along with CE was developed. The method was based on the fact that mercury species including methylmercury (MeHg), ethylmercury (EtHg), phenylmercury (PhHg), and Hg(II) were complexed with 1-(2-pyridylazo)-2-naphthol to form hydrophobic chelates and l-cysteine could displace 1-(2-pyridylazo)-2-naphthol to form hydrophilic chelates with the four mercury species. Factors affecting complex formation and extraction efficiency, such as pH value, type, and volume of extractive solvent and disperser solvent, concentration of the chelating agent, ultrasonic time, and buffer solution were investigated. Under the optimal conditions, the enrichment factors were 102, 118, 547, and 46, and the LODs were 1.79, 1.62, 0.23, and 1.50 µg/L for MeHg, EtHg, PhHg, and Hg(II), respectively. Method precisions (RSD, n = 5) were in the range of 0.29-0.54% for migration time, and 3.08-7.80% for peak area. Satisfactory recoveries ranging from 82.38 to 98.76% were obtained with seawater, lake, and tap water samples spiked at three concentration levels, respectively, with RSD (n = 5) of 1.98-7.18%. This method was demonstrated to be simple, convenient, rapid, cost-effective, and environmentally benign, and could be used as an ideal alternative to existing methods for analyzing trace residues of mercury species in water samples.


Assuntos
Eletroforese Capilar/métodos , Microextração em Fase Líquida/métodos , Mercúrio/análise , Compostos Organomercúricos/análise , Poluentes Químicos da Água/análise , Limite de Detecção , Modelos Lineares , Mercúrio/química , Mercúrio/classificação , Mercúrio/isolamento & purificação , Naftóis/química , Compostos Organomercúricos/química , Compostos Organomercúricos/classificação , Compostos Organomercúricos/isolamento & purificação , Reprodutibilidade dos Testes , Poluentes Químicos da Água/química , Poluentes Químicos da Água/classificação , Poluentes Químicos da Água/isolamento & purificação
14.
Sensors (Basel) ; 14(11): 21375-84, 2014 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-25397918

RESUMO

A new fluorescent probe P based on rhodamine for Cu2+ was synthesized and characterized. The new probe P showed high selectivity to Cu2+ over other tested metal ions. With optimal conditions, the proposed probe P worked in a wide linear range of 1.0 × 10(-6)-1.0 × 10(-5) M with a detection limit of 3.3 × 10(-7) M Cu2+ in ethanol-water solution (9:1, v:v, 20 mM HEPES, pH 7.0). Furthermore, it has been used for imaging of Cu2+ in living cells with satisfying results.


Assuntos
Cobre/química , Corantes Fluorescentes/química , Aumento da Imagem/métodos , Microscopia de Fluorescência/métodos , Rodaminas/química , Frações Subcelulares/ultraestrutura , Células Hep G2 , Humanos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
15.
Anal Bioanal Chem ; 405(17): 5843-52, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23657452

RESUMO

A dual cloud point extraction (dCPE) off-line enrichment procedure coupled with a hydrodynamic-electrokinetic two-step injection online enrichment technique was successfully developed for simultaneous preconcentration of trace phenolic estrogens (hexestrol, dienestrol, and diethylstilbestrol) in water samples followed by micellar electrokinetic chromatography (MEKC) analysis. Several parameters affecting the extraction and online injection conditions were optimized. Under optimal dCPE-two-step injection-MEKC conditions, detection limits of 7.9-8.9 ng/mL and good linearity in the range from 0.05 to 5 µg/mL with correlation coefficients R(2) ≥ 0.9990 were achieved. Satisfactory recoveries ranging from 83 to 108% were obtained with lake and tap water spiked at 0.1 and 0.5 µg/mL, respectively, with relative standard deviations (n = 6) of 1.3-3.1%. This method was demonstrated to be convenient, rapid, cost-effective, and environmentally benign, and could be used as an alternative to existing methods for analyzing trace residues of phenolic estrogens in water samples.


Assuntos
Cromatografia Capilar Eletrocinética Micelar/métodos , Disruptores Endócrinos/análise , Estrogênios/análise , Extração Líquido-Líquido/métodos , Fenóis/análise , Poluentes Químicos da Água/análise , Cromatografia Capilar Eletrocinética Micelar/instrumentação , Disruptores Endócrinos/isolamento & purificação , Estrogênios/isolamento & purificação , Água Doce/análise , Fenóis/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação
16.
Anal Chim Acta ; 1261: 341225, 2023 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-37147057

RESUMO

A rapid, fast, widely applicable liquid-solid microextraction and purification method of triazine herbicides (TRZHs) in muti-media samples using salting-out assisted liquid-liquid extraction (SALLE) combined with self-assembled monolithic spin columns-solid phase micro extraction (MSC-SPME) was developed. Environmentally friendly coconut shell biochar (CSB) was used as the adsorbents of MSC-SPME. Ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was the separation and determination method. The adsorption kinetics and isotherms were investigated to indicate the interaction between CSB and TRZHs. Several parameters influencing the liquid-solid microextraction efficiency, such as sample pH, salting-out solution volume and pH, sample loading speed, elution speed, elution ratio and volume of eluent were systematically investigated with the aid of orthogonal design. The whole extraction process was operated within 10 min. Under the optimum extraction and determination conditions, good linearities for three TRZHs were obtained in a range of 0.10-200.00 ng mL-1, with linear coefficients (R2) greater than 0.999. The limits of detection (LODs) and limits of quantification (LOQs) were in the range of 6.99-11.00 ng L-1 and 23.33-36.68 ng L-1, respectively. The recoveries of the three TRZHs in multi-media environmental samples were ranged from 69.00% to 124.72%, with relative standard deviations (RSDs) lower than 0.43%. This SALLE-MSC-SPME-UPLC-MS/MS method was successfully applied to the determination of TRZHs in environmental and food samples and exhibited the advantages of high efficiency and sensitivity, low cost, and environmental friendliness. Compared with the methods published before, CSB-MSC was green, rapid, easy-operated, and reduced the whole cost of the experiment; SALLE combined MSC-SPME eliminated the matrix references effectively; what's more, the SALLE-MSC-SPME-UPLC-MS/MS method could be applied to various sample without complicated sample pretreatment procedure.


Assuntos
Cocos , Herbicidas , Cromatografia Líquida/métodos , Espectrometria de Massas em Tandem/métodos , Herbicidas/análise , Cromatografia Líquida de Alta Pressão/métodos , Extração em Fase Sólida , Triazinas/análise
17.
J Photochem Photobiol B ; 240: 112654, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36724628

RESUMO

Long-term light exposure, especially in the spectrum of blue light, frequently causes excessive oxidative stress in dry age-related macular degeneration (AMD). Here, to gain insight into the underlying mechanism, we focused on mitochondrial dynamics alterations under long-term exposure to blue light in mouse and retinal cells. Six-month-old C57BL/6 mice were exposed to blue light (450 nm, 800 lx) for 2 weeks. The phenotypic changes in the retina were assayed using haematoxylin-eosin staining and transmission electron microscopy. Long-term blue light exposure significantly thinned each retinal layer in mice, induced retinal apoptosis and impaired retinal mitochondria. A retinal pigment epithelial cell line (ARPE-19) was used to verify the phototoxicity of blue light. Flow cytometry, immunofluorescence and MitoSox Red probe experiments confirmed that more total and mitochondria-specific ROS were generated in the blue light group than in the control group. Mito-Tracker Green probe showed fragmented mitochondrial morphology. The western blotting results indicated a significant increase in DRP1, OMA1, and BAX and a decrease in OPA1 and Bcl-2. In conclusion, long-term exposure to blue light damaged the retinas of mice, especially the ONL and RPE cells. There was destruction and dysfunction of mitochondria in RPE cells in vivo and in vitro. Mitochondrial dynamics were disrupted with characteristics of fusion-related obstruction after blue-light irradiation.


Assuntos
Degeneração Retiniana , Camundongos , Animais , Degeneração Retiniana/etiologia , Espécies Reativas de Oxigênio/metabolismo , Dinâmica Mitocondrial , Camundongos Endogâmicos C57BL , Retina/metabolismo , Estresse Oxidativo/efeitos da radiação , Luz , Epitélio Pigmentado da Retina
18.
iScience ; 26(12): 108448, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-38034364

RESUMO

This study aimed to investigate the effects of long-term pollution from different wavelengths of light on the corneal epithelium (CE) and identify potential biomarkers. Rabbits were exposed to red, green, blue, white, and environmental light for 6 weeks. The CE was assessed using various techniques such as fluorescein sodium staining, transcriptome sequencing, electron microscopy, and molecular assays. In human corneal epithelial cells (hCECs), the downregulation of vascular cell adhesion molecule 1 (VCAM1) in response to blue light (BL) pollution was observed. This downregulation of VCAM1 inhibited migration, increased reactive oxygen species (ROS) levels, and apoptosis, and inhibited the AKT/p70 S6 kinase cascade in hCECs. Animal experiments confirmed that BL pollution caused similar effects on the rabbit cornea, including increased ROS production, apoptosis, delayed wound healing, and decreased VCAM1 expression. Overall, BL-induced VCAM1 downregulation may impair CE and wound healing and promote ROS and apoptosis in vitro and in vivo.

19.
Electrophoresis ; 33(19-20): 2933-52, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23019127

RESUMO

CE is gaining great popularity as a well-established separation technique for many fields such as pharmaceutical research, clinical application, environmental monitoring, and food analysis, owing to its high resolving power, rapidity, and small amount of samples and reagents required. However, the sensitivity in CE analysis is still considered as being inferior to that in HPLC analysis. Diverse enrichment methods and techniques have been increasingly developed for overcoming this issue. In this review, we summarize the recent advances in enrichment techniques containing off-line preconcentration (sample preparation) and on-line concentration (sample stacking) to enhancing sensitivity in CE for trace analysis over the last 5 years. Some relatively new cleanup and preconcentration methods involving the use of dispersive liquid-liquid microextraction, supercritical fluid extraction, matrix solid-phase dispersion, etc., and the continued use and improvement of conventional SPE, have been comprehensively reviewed and proved effective preconcentration alternatives for liquid, semisolid, and solid samples. As for CE on-line stacking, we give an overview of field amplication, sweeping, pH regulation, and transient isotachophoresis, and the coupling of multiple modes. Moreover, some limitations and comparisons related to such methods/techniques are also discussed. Finally, the combined use of various enrichment techniques and some significant attempts are proposed to further promote analytical merits in CE.


Assuntos
Fracionamento Químico/instrumentação , Fracionamento Químico/métodos , Eletroforese Capilar/instrumentação , Eletroforese Capilar/métodos , Animais , Humanos
20.
Electrophoresis ; 33(15): 2454-63, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22887168

RESUMO

A simple and sensitive method for the simultaneous determination of four triazines from soil, strawberry, and tomato samples was developed by selective molecularly imprinted matrix solid-phase dispersion (MI-MSPD) coupled to micellar electrokinetic chromatography (MEKC). Using atrazine as template, the synthesized molecularly imprinted polymers (MIPs) were employed as the dispersion sorbent of MSPD to successfully extract atrazine and its analogs of simazine, ametryn, and propazine from the three different real samples, while matrix interferences were effectively eliminated simultaneously under the optimum extraction conditions. Excellent separation was achieved within 7 min by using an optimized buffer system composed of 30 mmol/L ammonium acetate, 20 mmol/L SDS, and 15% ACN at pH 9.45, obtained by orthogonal design. Good linearity was obtained in a range of 0.5-25 µg/g with the correlation coefficients R(2) ≥0.9991 except for strawberry sample within 1-25 µg/g, and limits of detection were between 12.9-31.5 ng/g in all the three samples. The average recoveries of the four triazines at three different spiked levels were ranged from 53.5 to 98.4% with the relative standard deviations of 1.28-4.89%. This method was proved convenient, costeffective, and environmental benign and could be used as an alternative tool to the existing methods for analyzing the residues of triazines in soil, fruit, and vegetable samples.


Assuntos
Cromatografia Capilar Eletrocinética Micelar/métodos , Fragaria/química , Impressão Molecular/métodos , Solo/química , Solanum lycopersicum/química , Extração em Fase Sólida/métodos , Triazinas/análise , Limite de Detecção , Resíduos de Praguicidas/análise , Resíduos de Praguicidas/isolamento & purificação , Análise de Regressão , Reprodutibilidade dos Testes , Poluentes do Solo/análise , Poluentes do Solo/isolamento & purificação , Triazinas/isolamento & purificação
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA