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1.
Nucleic Acids Res ; 52(12): 6811-6829, 2024 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-38676947

RESUMO

Protein arginine methyltransferase CARM1 has been shown to methylate a large number of non-histone proteins, and play important roles in gene transcriptional activation, cell cycle progress, and tumorigenesis. However, the critical substrates through which CARM1 exerts its functions remain to be fully characterized. Here, we reported that CARM1 directly interacts with the GATAD2A/2B subunit in the nucleosome remodeling and deacetylase (NuRD) complex, expanding the activities of NuRD to include protein arginine methylation. CARM1 and NuRD bind and activate a large cohort of genes with implications in cell cycle control to facilitate the G1 to S phase transition. This gene activation process requires CARM1 to hypermethylate GATAD2A/2B at a cluster of arginines, which is critical for the recruitment of the NuRD complex. The clinical significance of this gene activation mechanism is underscored by the high expression of CARM1 and NuRD in breast cancers, and the fact that knockdown CARM1 and NuRD inhibits cancer cell growth in vitro and tumorigenesis in vivo. Targeting CARM1-mediated GATAD2A/2B methylation with CARM1 specific inhibitors potently inhibit breast cancer cell growth in vitro and tumorigenesis in vivo. These findings reveal a gene activation program that requires arginine methylation established by CARM1 on a key chromatin remodeler, and targeting such methylation might represent a promising therapeutic avenue in the clinic.


Assuntos
Neoplasias da Mama , Montagem e Desmontagem da Cromatina , Regulação Neoplásica da Expressão Gênica , Complexo Mi-2 de Remodelação de Nucleossomo e Desacetilase , Proteína-Arginina N-Metiltransferases , Complexo Mi-2 de Remodelação de Nucleossomo e Desacetilase/metabolismo , Complexo Mi-2 de Remodelação de Nucleossomo e Desacetilase/genética , Proteína-Arginina N-Metiltransferases/genética , Proteína-Arginina N-Metiltransferases/metabolismo , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Neoplasias da Mama/metabolismo , Humanos , Feminino , Animais , Linhagem Celular Tumoral , Ciclo Celular/genética , Camundongos , Metilação , Arginina/metabolismo , Carcinogênese/genética , Ativação Transcricional
2.
Proc Natl Acad Sci U S A ; 119(34): e2200753119, 2022 08 23.
Artigo em Inglês | MEDLINE | ID: mdl-35969736

RESUMO

Jumonji C-domain-containing protein 6 (JMJD6), an iron (Fe2+) and α-ketoglutarate (α-KG)-dependent oxygenase, is expressed at high levels, correlated with poor prognosis, and considered as a therapeutic target in multiple cancer types. However, specific JMJD6 inhibitors that are potent in suppressing tumorigenesis have not been reported so far. We herein report that iJMJD6, a specific small-molecule inhibitor of JMJD6 with favorable physiochemical properties, inhibits the enzymatic activity of JMJD6 protein both in vitro and in cultured cells. iJMJD6 is effective in suppressing cell proliferation, migration, and invasion in multiple types of cancer cells in a JMJD6-dependent manner, while it exhibits minimal toxicity in normal cells. Mechanistically, iJMJD6 represses the expression of oncogenes, including Myc and CCND1, in accordance with JMJD6 function in promoting the transcription of these genes. iJMJD6 exhibits suitable pharmacokinetic properties and suppresses tumor growth in multiple cancer cell line- and patient-derived xenograft models safely. Furthermore, combination therapy with iJMJD6 and BET protein inhibitor (BETi) JQ1 or estrogen receptor antagonist fulvestrant exhibits synergistic effects in suppressing tumor growth. Taken together, we demonstrate that inhibition of JMJD6 enzymatic activity by using iJMJD6 is effective in suppressing oncogene expression and cancer development, providing a therapeutic avenue for treating cancers that are dependent on JMJD6 in the clinic.


Assuntos
Antineoplásicos , Histona Desmetilases com o Domínio Jumonji/antagonistas & inibidores , Neoplasias , Antineoplásicos/farmacologia , Carcinogênese/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Transformação Celular Neoplásica , Humanos , Neoplasias/tratamento farmacológico
3.
J Craniofac Surg ; 35(5): e466-e468, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38771195

RESUMO

Intraductal papillomas have been mostly described in minor salivary glands but are extremely rare in the parotid gland. Consequently, limited information is available to guide otolaryngologists and pathologists in managing intraductal papillomas, specifically in the parotid gland. Diagnosing intraductal papillomas in this location poses significant challenges. In this report, the authors present a new case and first conduct a systematic literature review of the intraductal papillomas originating from the parotid gland. This study contributes valuable insights that can improve diagnostic accuracy, providing more precise treatments, and patient outcomes in cases of intraductal papillomas in the parotid gland.


Assuntos
Neoplasias Parotídeas , Humanos , Diagnóstico Diferencial , Neoplasias Parotídeas/patologia , Neoplasias Parotídeas/diagnóstico , Neoplasias Parotídeas/cirurgia
4.
Plant Cell Physiol ; 64(1): 43-54, 2023 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-36201365

RESUMO

Non-photochemical quenching (NPQ) has been regarded as a safety valve to dissipate excess absorbed light energy not used for photochemistry. However, there exists no general consensus on the photoprotective role of NPQ. In the present study, we quantified the Photosystem II (PSII) photo-susceptibilities (mpi) in the presence of lincomycin, under red light given to five shade-acclimated tree species grown in the field. Photosynthetic energy partitioning theory was applied to investigate the relationships between mpi and each of the regulatory light-induced NPQ [Y(NPQ)], the quantum yield of the constitutive nonregulatory NPQ [Y(NO)] and the PSII photochemical yield in the light-adapted state [Y(PSII)] under different red irradiances. It was found that in the low to moderate irradiance range (50-800 µmol m-2 s-1) when the fraction of open reaction centers (qP) exceeded 0.4, mpi exhibited no association with Y(NPQ), Y(NO) and Y(PSII) across species. However, when qP < 0.4 (1,500 µmol m-2 s-1), there existed positive relationships between mpi and Y(NPQ) or Y(NO) but a negative relationship between mpi and Y(PSII). It is postulated that both Y(NPQ) and Y(NO) contain protective and damage components and that using only Y(NPQ) or Y(NO) metrics to identify the photo-susceptibility of a species is a risk. It seems that qP regulates the balance of the two components for each of Y(NPQ) and Y(NO). Under strong irradiance, when both protective Y(NPQ) and Y(NO) are saturated/depressed, the forward electron flow [i.e. Y(PSII)] acts as the last defense to resist photoinhibition.


Assuntos
Processos Fotoquímicos , Complexo de Proteína do Fotossistema II , Aclimatação , Luz , Fotossíntese/fisiologia , Complexo de Proteína do Fotossistema II/química , Complexo de Proteína do Fotossistema II/metabolismo
5.
Physiol Plant ; 175(2): e13880, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36840627

RESUMO

At the outer canopy, the white leaves of Actinidia kolomikta can turn pink but they stay white in A. polygama. We hypothesized that the different leaf colors in the two Actinidia species may represent different photoprotection strategies. To test the hypothesis, leaf optical spectra, anatomy, chlorophyll a fluorescence, superoxide (O2 ˙- ) concentration, photosystem II photo-susceptibility, and expression of anthocyanin-related genes were investigated. On the adaxial side, light reflectance was the highest for white leaves of A. kolomikta, followed by its pink leaves and white leaves of A. polygama, and the absorptance for white leaves of A. kolomikta was the lowest. Chlorophyll and carotenoid content of white and pink leaves in A. kolomikta were significantly lower than those of A. polygama, while the relative anthocyanin content of pink leaves was the highest. Chloroplasts of palisade cells of white leaves in A. kolomikta were not well developed with a lower maximum quantum efficiency of PSII than the other types of leaves (pink leaves of A. kolomikta and white leaves of A. Polygama at the inner/outer canopy). After high light treatment from the abaxial surface, Fv /Fm decreased to a larger extent for white leaves of A. kolomikta than pink leaf and white leaves of A. polygama, and its non-photochemical quenching was also the lowest. White leaves of A. kolomikta showed higher O2 ˙- concentration compared to pink leaves under the same strong irradiance. The expression levels of anthocyanin biosynthetic genes in pink leaves were higher than in white leaves. These results indicate that white leaves of A. kolomikta apply a reflection strategy for photoprotection, while pink leaves resist photoinhibition via anthocyanin accumulation.


Assuntos
Actinidia , Actinidia/metabolismo , Clorofila A/análise , Antocianinas/metabolismo , Clorofila/metabolismo , Fotossíntese/fisiologia , Complexo de Proteína do Fotossistema II/metabolismo , Folhas de Planta/metabolismo , Luz
6.
New Phytol ; 235(2): 446-456, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35451127

RESUMO

Photosystem II (PSII), which splits water molecules at minimal excess photochemical potential, is inevitably photoinactivated during photosynthesis, resulting in compromised photosynthetic efficiency unless it is repaired. The energy cost of PSII repair is currently uncertain, despite attempts to calculate it. We experimentally determined the energy cost of repairing each photoinactivated PSII in cotton (Gossypium hirsutum) leaves, which are capable of repairing PSII in darkness. As an upper limit, 24 000 adenosine triphosphate (ATP) molecules (including any guanosine triphosphate synthesized at the expense of ATP) were required to repair one entire PSII complex. Further, over a 7-h illumination period at 526-1953 µmol photons m-2 s-1 , the ATP requirement for PSII repair was on average up to 4.6% of the ATP required for the gross carbon assimilation. Each of these two measures of ATP requirement for PSII repair is two- to three-fold greater than the respective reported calculated value. Possible additional energy sinks in the PSII repair cycle are discussed.


Assuntos
Gossypium , Complexo de Proteína do Fotossistema II , Trifosfato de Adenosina/metabolismo , Clorofila , Gossypium/metabolismo , Luz , Fotossíntese , Complexo de Proteína do Fotossistema II/metabolismo , Folhas de Planta/metabolismo
7.
BMC Endocr Disord ; 22(1): 44, 2022 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-35189861

RESUMO

BACKGROUND: Thyroid function is known to be closely linked with type 2 diabetes, but data on the association between thyroid function and gestational diabetes mellitus (GDM) are inconsistent. METHODS: A total of 2849 pregnant women were included in this retrospective study. Serum concentrations of thyroid indicators (free tetraiodothyronine, FT4; thyroid-stimulating hormone, TSH; and thyroid peroxidase antibody, TPO Ab) were obtained from a clinical laboratory. The presence of GDM were drawn from medical records. The clinical subtypes of thyroid function (euthyroidism, subclinical hypothyroidism, hyperthyroidism, and isolated hypothyroxinemia) were categorized according to the thresholds of the 2.5th/97.5th and 10th/90th percentiles of TSH and FT4 concentrations. A concentration of > 34 IU/L was defined as indicating TPO Ab-positivity. RESULTS: Two hundred and thirty-five (8.25%) of the 2849 women were TPO Ab-positive. Higher serum concentrations of FT4 (top vs. bottom tertiles) was found to be negatively associated with the risk of GDM. The corresponding odds (OR) values (top tertile vs. bottom tertile) were 0.71 [95% confidence interval (CI): 0.54, 0.93]. No significant associations were observed between the extremely 2.5th/97.5th or 10th/90th percentiles of FT4 concentration, TSH concentration, thyroid function subtypes (vs. euthyroidism), TPO Ab-positivity (vs. -negativity), and the GDM risk. The corresponding results remained similar when TPO Ab-positive subjects were excluded. CONCLUSIONS: A negative association with the risk of GDM was observed for the highest FT4 concentrations tertile. No significant associations were found between the TSH concentration, thyroid function subtypes, TPO Ab positivity, and the GDM risk.


Assuntos
Diabetes Gestacional , Doenças da Glândula Tireoide/complicações , Hormônios Tireóideos/sangue , Adulto , Biomarcadores/sangue , China , Feminino , Humanos , Gravidez , Estudos Retrospectivos , Testes de Função Tireóidea
8.
Environ Res ; 208: 112694, 2022 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-35007540

RESUMO

Detailed prediction of the adsorption amounts of organic pollutants in water is essential to the clean development and management of water resources. In this study, Kriging and polyparameter linear free energy relationship model are coupled to predict adsorption capacity of organic pollutants by biochar and resin. It's based on 1750 adsorption experimental data sets which contains 73 organic compounds on 50 biochars and 30 polymer resins. The Kriging-LFER model shows better accuracy and predictive performance for adsorption (R2 are 0.940 and 0.976) than the published NN-LFER model (R2 are 0.870 and 0.880). Local sensitivity analysis method is adopted to evaluate the influence of each variable on the adsorption coefficient of resin and find out that top sensitive parameters are V and log Ce, to guide parameter optimization. Data's uncertainty analysis is presented by Monte Carlo method. It predicts that the adsorption coefficient will range from 0.062 to 0.189 under the 95% confidence interval. The Kriging-LFER model provides great significance for understanding the importance of various parameters, reducing the number of experiments, adjusting the direction of experimental improvement, and evaluating the fate of organic pollutants in the environment.


Assuntos
Carvão Vegetal , Compostos Orgânicos , Adsorção , Aprendizado de Máquina
9.
Inorg Chem ; 59(11): 7504-7511, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32436384

RESUMO

This work designed a nonionic extended dialdehyde 6,6'-(phenylazanediyl)dipicolinaldehyde (PDPA) for constructing Schiff-base macrocyclic complexes with weaker metal-ligand interactions, so as to solve the long-standing challenges of transmetalation and demetallization in macrocyclic complexes. An enantiomeric pair of open-oyster-like 26-membered [2 + 2] Schiff-base macrocyclic dinuclear Cd(II) complexes (S,S-1a, R,R-1b) could be obtained, having S,S/R,R-1,2-diaminocyclohexane (S,S/R,R-DACH) precursors, while Cu(II) ion template only resulted in a mononuclear Schiff-base Cu(II) acyclic complex (S,S-2) accompanied by the half-oxidation of PDPA instead of expected [2 + 2] Cu(II) macrocyclic complexes. It is suggested that the weak oxidization capability of Cu(II) ion is responsible for the formation of S,S-2 because X-ray photoelectron spectroscopy (XPS) for the solid powder of reaction mixture of direct Cu(II) ion template synthesis implies that both Cu(I) and Cu(II) species are present. In fact, corresponding [2 + 2] dinuclear Cu(II) macrocycles and even metal-free macrocycles unsuitable for direct synthesis can be obtained via Cd(II) → Cu(II) transmetalation and Na2S demetalation verified by ESI-MS and UV-vis spectra. In addition, control experiments indicate that the synthesis of metal-free macrocycles via the direct nontemplate method merely results in the mixture of multiple components of [1 + 1], [2 + 2], and [3 + 3] Schiff-base macrocycles, and they are difficult to isolate.

10.
BMC Pregnancy Childbirth ; 20(1): 465, 2020 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-32795269

RESUMO

BACKGROUND: Previous evidence has suggested that lower gestational vitamin D levels might increase the risks of adverse pregnancy and birth outcomes. The results remain inconsistent and require further exploration. METHODS: A total of 2814 Chinese mother-infant pairs were included in this retrospective cohort study. Serum concentrations of 25(OH)D were reviewed in early pregnancy (16.3 ± 2.3 weeks). Outcomes of maternal gestational diabetes mellitus (GDM), cesarean section, fetal distress, preterm birth, low birth weight (LBW), and macrosomia were extracted from the medical records. Cox regression analysis was used to explore these associations. RESULTS: In total, 19.3% of mothers were pregnant at an advanced age (≥35 years), and 40.3% of pregnant women had vitamin D deficiency (< 50 nmol/L). After adjusting for potential covariates, the hazard ratio (HR) (95% CI) per standard deviation (SD) increase of serum 25(OH)D concentrations was 0.86 (0.779, 0.951) for GDM, 0.844 (0.730, 0.976) for preterm birth, and 0.849 (0.726, 0.993) for LBW. Similar protective associations were found for GDM, cesarean section, and preterm birth for a better vitamin D status when compared with vitamin D deficiency. CONCLUSION: Higher early pregnancy vitamin D was associated with a lower risk of GDM, cesarean section, preterm birth, and LBW.


Assuntos
Complicações na Gravidez/epidemiologia , Resultado da Gravidez , Deficiência de Vitamina D/epidemiologia , Adulto , Cesárea , Estudos de Coortes , Diabetes Gestacional/epidemiologia , Feminino , Sofrimento Fetal/epidemiologia , Macrossomia Fetal/epidemiologia , Humanos , Recém-Nascido de Baixo Peso , Recém-Nascido , Recém-Nascido Prematuro , Gravidez , Primeiro Trimestre da Gravidez , Segundo Trimestre da Gravidez , Nascimento Prematuro , Estudos Retrospectivos , Medição de Risco , Fatores de Risco
11.
Plant Cell Physiol ; 60(10): 2206-2219, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31271439

RESUMO

Photosynthetic induction, a gradual increase in photosynthetic rate on a transition from darkness or low light to high light, has ecological significance, impact on biomass accumulation in fluctuating light and relevance to photoprotection in strong light. However, the experimental quantification of the component electron fluxes in and around both photosystems during induction has been rare. Combining optimized chlorophyll fluorescence, the redox kinetics of P700 [primary electron donor in Photosystem I (PSI)] and membrane inlet mass spectrometry in the absence/presence of inhibitors/mediator, we partially estimated the components of electron fluxes in spinach leaf disks on transition from darkness to 1,000 �mol photons�m-2�s-1 for up to 10 min, obtaining the following findings: (i) the partitioning of energy between both photosystems did not change noticeably; (ii) in Photosystem II (PSII), the combined cyclic electron flow (CEF2) and charge recombination (CR2) to the ground state decreased gradually toward 0 in steady state; (iii) oxygen reduction by electrons from PSII, partly bypassing PSI, was small but measurable; (iv) cyclic electron flow around PSI (CEF1) peaked before becoming somewhat steady; (v) peak magnitudes of some of the electron fluxes, all probably photoprotective, were in the descending order: CEF1 > CEF2 + CR2 > chloroplast O2 uptake; and (vi) the chloroplast NADH dehydrogenase-like complex appeared to aid the antimycin A-sensitive CEF1. The results are important for fine-tuning in silico simulation of in vivo photosynthetic electron transport processes; such simulation is, in turn, necessary to probe partial processes in a complex network of interactions in response to environmental changes.


Assuntos
Transporte de Elétrons , Oxigênio/metabolismo , Fotossíntese/fisiologia , Complexo de Proteína do Fotossistema I/metabolismo , Complexo de Proteína do Fotossistema II/metabolismo , Spinacia oleracea/fisiologia , Antimicina A/farmacologia , Dióxido de Carbono/metabolismo , Clorofila/metabolismo , Cloroplastos/metabolismo , Escuridão , Fluorescência , Cinética , Luz , Oxirredução , Folhas de Planta/fisiologia , Folhas de Planta/efeitos da radiação , Spinacia oleracea/efeitos da radiação
12.
Analyst ; 144(7): 2256-2263, 2019 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-30810145

RESUMO

In this study, sulfur-nitrogen co-doped carbon nanoribbon (SNCNR) polymers with stable dual-emission fluorescence were synthesized using a one-step traditional hydrothermal method of 6-mercaptopurine in an aqueous methanol solution. Unexpectedly, the as-prepared SNCNRs with excitation-independent emission, as carbon nanomaterial derivatives, showed stable dispersions of a reticular-like shape and different lengths in the skeleton diameter. Compared with other carbon nanomaterials, the SNCNRs dramatically improved the electronic properties and surface chemical reactivities, and exhibited a sensitive ratiometric response to quercetin (Que) because of the Meisenheimer-like complexes formed through π-π stacking and electrostatic interaction. By using this SNCNR sensor, excellent ratiometric linear relationships (FL345 nm/FL420 nm) existed between the degree of quenching of the SNCNRs and the concentrations of Que in the range of 50.0 nM to 200 µM, and the limit of detection was 21.13 nM (3σ/k). Meanwhile, this sensor shows high selectivity for Que over other biomolecules, most amino acids and metal ions under the same conditions. Finally, this fluorescent probe was successfully applied to the direct analysis of Que in bovine serum and some beverage samples, which showed that it has potential for use in applications in clinical diagnosis and food analysis, and may pave the way for the design of effective fluorescent probes for other biologically related targets and food protection.


Assuntos
Carbono/química , Corantes Fluorescentes/química , Nanoestruturas/química , Polímeros/química , Quercetina/análise , Animais , Bovinos , Filtração , Limite de Detecção , Modelos Moleculares , Conformação Molecular , Quercetina/sangue , Quercetina/química , Eletricidade Estática , Fatores de Tempo
13.
Inorg Chem ; 58(12): 7812-7821, 2019 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-31185551

RESUMO

A new flexible 2-ethylthiophene pendant-armed dialdehyde (H2tdd) was reacted with 1,3-propanediamine, [( S, S),( R, R),(±)]-1,2-diaminocyclohexane, and 1,2-bis(2-aminoethoxy)ethane, giving birth to 36-membered [2 + 2] Schiff-base macrocyclic trinuclear ZnII complex 1, 18-membered [1 + 1] mononuclear ZnII macrocycles 2-4, chiral/racemic 34-membered [2 + 2] dinuclear ZnII complexes 5-9, and 46-membered [2 + 2] dinuclear ZnII macrocycles 10-12 via ZnII ion template-assisted Schiff-base condensation. It is worth mentioning that the secondary template effects for nitrate and halide counterions have been observed in the 1,3-propanediamine involved imine condensation. In all [2 + 2] ZnII macrocycles, dinuclear complexes 5-9 display a full-folded molecular conformation, while trinuclear complex 1 and dinuclear complexes 10-12 exhibit distinct half-folded structures in the presence or absence of intramolecular π-π stacking interactions between two phenolic rings of the dialdehyde component. Interestingly, a solvent-induced single-crystal-to-single-crystal transformation was first achieved for two types of solvated mononuclear macrocycles 3a and 3b (H2O vs CH3CN) with folded and unfolded ligand conformations. In addition, the photoluminescent properties were studied for this family of Schiff-base macrocyclic ZnII complexes as well as the dialdehyde precursor H2tdd.

14.
Photosynth Res ; 127(3): 307-19, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26297354

RESUMO

Oxygen effects have long been ambiguous: exacerbating, being indifferent to, or ameliorating the net photoinactivation of Photosystem II (PS II). We scrutinized the time course of PS II photoinactivation (characterized by rate coefficient k i) in the absence of repair, or when recovery (characterized by k r) occurred simultaneously in CO2 ± O2. Oxygen exacerbated photoinactivation per se, but alleviated it by mediating the utilization of electrons. With repair permitted, the gradual net loss of functional PS II during illumination of leaves was better described phenomenologically by introducing τ, the time for an initial k r to decrease by half. At 1500 µmol photons m(-2) s(-1), oxygen decreased the initial k r but increased τ. Similarly, at even higher irradiance in air, there was a further decrease in the initial k r and increase in τ. These observations are consistent with an empirical model that (1) oxygen increased k i via oxidative stress but decreased it by mediating the utilization of electrons; and (2) reactive oxygen species stimulated the degradation of photodamaged D1 protein in PS II (characterized by k d), but inhibited the de novo synthesis of D1 (characterized by k s), and that the balance between these effects determines the net effect of O2 on PS II functionality.


Assuntos
Luz , Oxigênio/metabolismo , Complexo de Proteína do Fotossistema II/metabolismo , Folhas de Planta/metabolismo , Spinacia oleracea/metabolismo , Simulação por Computador , Transporte de Elétrons/efeitos dos fármacos , Transporte de Elétrons/efeitos da radiação , Cinética , Lincomicina/farmacologia , Modelos Biológicos , Oxigênio/farmacologia , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/efeitos da radiação , Spinacia oleracea/efeitos dos fármacos , Spinacia oleracea/efeitos da radiação , Fatores de Tempo
15.
Photosynth Res ; 129(3): 239-51, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26846653

RESUMO

Sixty years ago Arnon and co-workers discovered photophosphorylation driven by a cyclic electron flux (CEF) around Photosystem I. Since then understanding the physiological roles and the regulation of CEF has progressed, mainly via genetic approaches. One basic problem remains, however: quantifying CEF in the absence of a net product. Quantification of CEF under physiological conditions is a crucial prerequisite for investigating the physiological roles of CEF. Here we summarize current progress in methods of CEF quantification in leaves and, in some cases, in isolated thylakoids, of C3 plants. Evidently, all present methods have their own shortcomings. We conclude that to quantify CEF in vivo, the best way currently is to measure the electron flux through PS I (ETR1) and that through PS II and PS I in series (ETR2) for the whole leaf tissue under identical conditions. The difference between ETR1 and ETR2 is an upper estimate of CEF, mainly consisting, in C3 plants, of a major PGR5-PGRL1-dependent CEF component and a minor chloroplast NDH-dependent component, where PGR5 stands for Proton Gradient Regulation 5 protein, PGRL1 for PGR5-like photosynthesis phenotype 1, and NDH for Chloroplast NADH dehydrogenase-like complex. These two CEF components can be separated by the use of antimycin A to inhibit the former (major) component. Membrane inlet mass spectrometry utilizing stable oxygen isotopes provides a reliable estimation of ETR2, whilst ETR1 can be estimated from a method based on the photochemical yield of PS I, Y(I). However, some issues for the recommended method remain unresolved.


Assuntos
Antimicina A/farmacologia , Complexo de Proteína do Fotossistema I/metabolismo , Plantas/metabolismo , Cloroplastos/metabolismo , Transporte de Elétrons/efeitos dos fármacos , Elétrons , Fotossíntese/efeitos dos fármacos , Complexo de Proteína do Fotossistema I/efeitos dos fármacos , Complexo de Proteína do Fotossistema II/metabolismo , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Plantas/efeitos dos fármacos , Tilacoides/metabolismo
16.
Photosynth Res ; 126(2-3): 399-407, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26101037

RESUMO

Action spectra of photoinactivation of Photosystem II (PS II) in wild-type and chlorophyll b-less barley leaf segments were obtained. Photoinactivation of PS II was monitored by the delivery of electrons from PS II to PS I following single-turnover flashes superimposed on continuous far-red light, the time course of photoinactivation yielding a rate coefficient k i. Susceptibility of PS II to photoinactivation was quantified as the ratio of k i to the moderate irradiance (I) of light at each selected wavelength. k i/I was very much higher in blue light than in red light. The experimental conditions permitted little excess light energy absorbed by chlorophyll (not utilized in photochemical conversion or dissipated in controlled photoprotection) that could lead to photoinactivation of PS II. Therefore, direct absorption of light by Mn in PS II, rather than by chlorophyll, was more likely to have initiated the much more severe photoinactivation in blue light than in red light. Mutant leaves were ca. 1.5-fold more susceptible to photoinactivation than the wild type. Neither the excess-energy mechanism nor the Mn mechanism can explain this difference. Instead, the much lower chlorophyll content of mutant leaves could have exerted an exacerbating effect, possibly partly due to less mutual shading of chloroplasts in the mutant leaves. In general, which mechanism dominates depends on the experimental conditions.


Assuntos
Hordeum/efeitos da radiação , Complexo de Proteína do Fotossistema II/efeitos da radiação , Clorofila/metabolismo , Cloroplastos/metabolismo , Fluorescência , Hordeum/metabolismo , Luz , Complexo de Proteína do Fotossistema II/metabolismo
17.
Cell Biochem Funct ; 33(6): 356-66, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26178702

RESUMO

The study was aimed to investigate the mechanism and administration timing of bone marrow-derived mesenchymal stem cells (BMSCs) in bleomycin (BLM)-induced pulmonary fibrosis mice. Thirty-six mice were divided into six groups: control group (saline), model group (intratracheal administration of BLM), day 1, day 3 and day 6 BMSCs treatment groups and hormone group (hydrocortisone after BLM treatment). BMSCs treatment groups received BMSCs at day 1, 3 or 6 following BLM treatment, respectively. Haematoxylin and eosin and Masson staining were conducted to measure lung injury and fibrosis, respectively. Matrix metalloproteinase (MMP9), tissue inhibitor of metalloproteinase-1 (TIMP-1), γ-interferon (INF-γ) and transforming growth factor ß1 (TGF-ß) were detected in both lung tissue and serum. Histologically, the model group had pronounced lung injury, increased inflammatory cells and collagenous fibres and up-regulated MMP9, TIMP-1, INF-γ and TGF-ß compared with control group. The histological appearance of lung inflammation and fibrosis and elevation of these parameters were inhibited in BMSCs treatment groups, among which, day 3 and day 6 treatment groups had less inflammatory cells and collagenous fibres than day 1 treatment group. BMSCs might suppress lung fibrosis and inflammation through down-regulating MMP9, TIMP-1, INF-γ and TGF-ß. Delayed BMSCs treatment might exhibit a better therapeutic effect. Highlights are as follows: 1. BMSCs repair lung injury induced by BLM. 2. BMSCs attenuate pulmonary fibrosis induced by BLM. 3. BMSCs transplantation down-regulates MMP9 and TIMP-1. 4. BMSCs transplantation down-regulates INF-γ and TGF-ß. 5. Delayed transplantation timing of BMSCs might exhibit a better effect against BLM.


Assuntos
Interferon gama/metabolismo , Metaloproteinase 9 da Matriz/metabolismo , Células-Tronco Mesenquimais/metabolismo , Fibrose Pulmonar/metabolismo , Inibidor Tecidual de Metaloproteinase-1/metabolismo , Fator de Crescimento Transformador beta1/metabolismo , Animais , Antibióticos Antineoplásicos/metabolismo , Bleomicina , Medula Óssea/metabolismo , Inflamação/metabolismo , Lesão Pulmonar/metabolismo , Camundongos Endogâmicos C57BL , Fibrose Pulmonar/induzido quimicamente
18.
Physiol Plant ; 152(3): 403-13, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24862879

RESUMO

We sought a rapid, non-intrusive, whole-tissue measure of the functional photosystem II (PS II) content in leaves. Summation of electrons, delivered by a single-turnover flash to P700(+) (oxidized PS I primary donor) in continuous background far-red light, gave a parameter S in absorbance units after taking into account an experimentally determined basal electron flux that affects P700 redox kinetics. S was linearly correlated with the functional PS II content measured by the O(2) yield per single-turnover repetitive flash in Arabidopsis thaliana expressing an antisense construct to the PsbO (manganese-stabilizing protein in PS II) proteins of PS II (PsbO mutants). The ratio of S to z(max) (total PS I content in absorbance units) was comparable to the PS II/PS I reaction-center ratio in wild-type A. thaliana and in control Spinacea oleracea. Both S and S/z(max) decreased in photoinhibited spinach leaf discs. The whole-tissue functional PS II content and the PS II/photosystem I (PS I) ratio can be non-intrusively monitored by S and S/z(max), respectively, using a quick P700 absorbance protocol compatible with modern P700 instruments.


Assuntos
Arabidopsis/metabolismo , Clorofila/metabolismo , Complexo de Proteína do Fotossistema I/metabolismo , Complexo de Proteína do Fotossistema II/metabolismo , Spinacia oleracea/metabolismo , Arabidopsis/efeitos da radiação , Transporte de Elétrons , Cinética , Modelos Biológicos , Oxirredução , Oxigênio/metabolismo , Folhas de Planta/metabolismo , Folhas de Planta/efeitos da radiação , Spinacia oleracea/efeitos da radiação
19.
Beijing Da Xue Xue Bao Yi Xue Ban ; 46(5): 777-81, 2014 Oct 18.
Artigo em Zh | MEDLINE | ID: mdl-25331404

RESUMO

OBJECTIVE: To evaluate the current condition of urban road traffic injuries (RTIs) according to Beijing Emergency Medical Center (BEMC) from Jan. 1, 2004 to Dec. 31, 2010, analyze the social characteristics and explore the possible methods for prevention and improvement. METHODS: Using data from the Beijing Emergency Medical Center, we collected 19 550 victims who were involved in RTIs in Beijing from Jan. 1, 2004 to Dec. 31, 2010. The personal information, time of the injury event, road user type and striking vehicle type, as well as the site and severity of injury, were analyzed using Excel 2007 and SPSS 17.0 software with ANOVA of variance and Chi-squared tests. RESULTS: The annual rate of RTIs was 120.0 per 100 000 people in Beijing, and the mortality rate was about 4.97 per 100 000 people. Male victims were more than female victims (11 737 persons vs. 7 618 persons).The mean age was (72.92 ± 5.67) years. Overall, RTIs in all the age groups happened in October commonly, and were inclined to daytime, especially at noon. But different age groups had their special hour distribution features of RTIs. Traffic collisions occurred most frequently in pedestrians and cyclists (7 588,38.81%;3 790,19.39%). Majorities of victims presented with head injuries and lower-limb injuries(8 343,42.68%; 6 828,34.93%). These collisions included car striking accidents (11 490, 58.77%). And most of the older adults were classified as medium in severity (11 718, 59.94%). CONCLUSION: The prevention and treatment of RTIs, should focus on targeted prevention solutions and standardized pre-hospital rescue, according to specific population, time interval and vehicle usage.


Assuntos
Acidentes de Trânsito/estatística & dados numéricos , Idoso , China/epidemiologia , Cidades , Traumatismos Craniocerebrais/epidemiologia , Serviços Médicos de Emergência , Feminino , Hospitais , Humanos , Traumatismos da Perna/epidemiologia , Masculino
20.
Sci Total Environ ; 927: 171867, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38531440

RESUMO

Biochar colloids (BCs) can be used as adsorbent materials for remediation of phenanthrene due to their high specific surface area and other characteristics. Understanding the effects of phenanthrene on the transport of BCs contributes to facilitate the removal of phenanthrene in soil and water habitats. In this work, the influence of phenanthrene on the transport of BCs under different environmental factors (pH, ionic strength (IS), media size) in a one-dimensional sand column was firstly explored together with a real-time visualization system to explore the transport mechanism of BCs in two-dimensional sand tank. The results show that phenanthrene adsorbed on the surface of BCs, shielded its surface charge and reduced the mobility of BCs in porous media. Acidic conditions promoted the agglomeration of BCs and adsorption of phenanthrene, resulting in a 51.03 % decrease in the maximum breakthrough rate of BCs compared to alkaline conditions. The same was true for the high IS condition, where the maximum breakthrough rate of BCs was only 0.95 % at IS = 50. Additionally, there was a substantial and positive correlation between media particle size and BCs mobility. As the quartz sand particle size increased, the maximum breakthrough rates of BCs were 2.67 %, 33.28 %, and 52.27 % in the 1-D experiment, and 0, 13.88 %, and 13.10 % in the 2-D experiment, respectively. The contact area of BCs with the medium expands under the fine particle size condition, leading to a significant decrease in the mobility of BCs at low potentials influenced by phenanthrene. This finding is significant for biochar application in phenanthrene contaminated soil and groundwater remediation.

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