RESUMO
Kernel weight is a critical factor that essentially affects maize (Zea mays) yield. In natural inbred lines, popcorn kernels exhibit overtly smaller sizes compared to dent corn kernels, and kernel weight, which is controlled by multiple genetic loci, varies widely. Here, we characterized a major quantitative trait locus on chromosome 1, responsible for controlling kernel weight (qKW1) and size. The qKW1 locus encodes a protein containing a seven in absentia domain with E3 ubiquitin ligase activity, expressed prominently from the top to the middle region of the endosperm. The presence and function of qKW1 were confirmed through ZmKW1 gene editing, where the mutations in ZmKW1 within dent corn significantly increased kernel weight, consistent with alterations in kernel size, while overexpression of ZmKW1 had the opposite effect. ZmKW1 acts as a negative regulator of kernel weight and size by reducing both the number and size of the endosperm cells and impacting endosperm filling. Notably, the popcorn allele qKW1N and the dent corn allele qKW1D encode identical proteins; however, the differences in promoter activity arise due to the insertion of an Indel-1346 sequence in the qKW1N promoter, resulting in higher expression levels compared to qKW1D, thus contributing to the variation in kernel weight and size between popcorn and dent corn kernels. Linkage disequilibrium analysis of the 2.8 kb promoter region of ZmKW1 in a dataset comprising 111 maize association panels identified two distinct haplotypes. Our results provide insight into the mechanisms underlying kernel development and yield regulation in dent corn and popcorn, with a specific focus on the role of the ubiquitination system.
Assuntos
Proteínas de Plantas , Locos de Características Quantitativas , Zea mays , Zea mays/genética , Zea mays/crescimento & desenvolvimento , Zea mays/metabolismo , Locos de Características Quantitativas/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Variação Genética , Endosperma/genética , Endosperma/metabolismo , Endosperma/crescimento & desenvolvimento , Sementes/genética , Sementes/crescimento & desenvolvimento , Sementes/metabolismo , Regulação da Expressão Gênica de PlantasRESUMO
Members of the ADP-ribosylation factor family, which are GTP-binding proteins, are involved in metabolite transport, cell division, and expansion. Although there has been a significant amount of research on small GTP-binding proteins, their roles and functions in regulating maize kernel size remain elusive. Here, we identified ZmArf2 as a maize ADP-ribosylation factor-like family member that is highly conserved during evolution. Maize zmarf2 mutants showed a characteristic smaller kernel size. Conversely, ZmArf2 overexpression increased maize kernel size. Furthermore, heterologous expression of ZmArf2 dramatically elevated Arabidopsis and yeast growth by promoting cell division. Using expression quantitative trait loci (eQTL) analysis, we determined that ZmArf2 expression levels in various lines were mainly associated with variation at the gene locus. The promoters of ZmArf2 genes could be divided into two types, pS and pL, that were significantly associated with both ZmArf2 expression levels and kernel size. In yeast-one-hybrid screening, maize Auxin Response Factor 24 (ARF24) is directly bound to the ZmArf2 promoter region and negatively regulated ZmArf2 expression. Notably, the pS and pL promoter types each contained an ARF24 binding element: an auxin response element (AuxRE) in pS and an auxin response region (AuxRR) in pL, respectively. ARF24 binding affinity to AuxRR was much higher compared with AuxRE. Overall, our results establish that the small G-protein ZmArf2 positively regulates maize kernel size and reveals the mechanism of its expression regulation.
Assuntos
Ácidos Indolacéticos , Zea mays , Zea mays/metabolismo , Haplótipos , Ácidos Indolacéticos/metabolismo , Saccharomyces cerevisiae/metabolismo , Fatores de Ribosilação do ADP/genética , Fatores de Ribosilação do ADP/metabolismo , Regulação da Expressão Gênica de Plantas/genéticaRESUMO
Digital watermarking technology is an important means to effectively protect three-dimensional (3D) model data. Among them, "blind detection" and "robustness" are key and difficult points in the current research of digital watermarking technology based on 3D models. In order to realize the blind detection of a watermark and improve its robustness against various common attacks at the same time, this paper proposes a dual blind watermarking method based on the normal feature of the centroid of first-ring neighboring points. The local spherical coordinate system is constructed by calculating two different normal vectors, and the first pattern watermark and the second random binary sequence watermark are embedded, respectively. The experimental results show that this method can not only realize the blind detection of dual watermarks, but also have the ability to resist common attacks such as translation, rotation, scaling, cropping, simplification, smoothing, noise, and vertex reordering to a certain extent.
RESUMO
Objectives: Atrial fibrillation (AF) is the most frequent arrhythmia, and myocardial fibrosis (MF) has a close association with atrial remodeling and leads to AF. This study aimed to explore the function of the long non-coding RNA (lncRNA) differentiation antagonizing non-protein coding RNA (Dancr)/microRNA (miR)-146b-5p/Smad5 axis on MF in AF mice. Methods: AF mouse models were established. Overexpression Dancr lentivirus was injected into AF mice to increase Dancr expression in myocardial tissues. LncRNA Dancr, miR-146b-5p, and Smad5 expression levels and inflammatory factors (IL-18 and TNF-α) in the myocardial tissues were measured. MF was measured and the expression levels of MF-related genes (COL1A1, α-SMA, and FN1) were detected. In addition, in vitro HL-1 cell rapid pacing models were constructed, and after lncRNA Dancr and miR-146b-5p-related construct transfection, cell viability and cell apoptosis were determined. Results: LncRNA Dancr up-regulation ameliorated MF in the AF mice, reduced IL-18 and TNF-α expression levels in myocardial tissues, and decreased COL1A1, α-SMA, and FN1 expression levels. The in vitro HL-1 cell rapid pacing models suggested that miR-146b-5p overexpression reversed the inhibitory effects of lncRNA Dancr overexpression on MF in HL-1 cells, and Smad5 interference reversed the ameliorative effects of miR-146b-5p interference on MF in HL-1 cells. Conclusions: LncRNA Dancr can sponge miR-146b-5p to promote Smad5 expression, thereby delaying MF in AF mice.
RESUMO
Dissolved organic matter (DOM) plays an important environmental and ecological role in inland aquatic systems, including lakes. In this study, using fluorescence analysis, we investigated the seasonal dynamics of DOM characteristics in Changshou Lake, which is a typical inland lake in the Three Gorges Reservoir (TGR) area. We also discuss the environmental implications of DOM for mercury (Hg) dynamics. Based on the origins of two end-members, the variations in DOM observed in this study in Changshou Lake suggest that hydrological processes (e.g., terrestrial inputs resulting from runoff and humic-like component residences) and biological activities (e.g., microbial and algae growth) are the two main principal components controlling the seasonal dynamics of DOM characteristics. Furthermore, the dynamics of dissolved Hg co-varied with variations in DOM properties, rather than with dissolved organic carbon (DOC) concentrations. This indicates that the previously reported simple correlations between DOC and Hg were not comprehensive and may lead to misunderstanding the interactions between DOM and Hg. Therefore, we recommend that when using DOM-Hg correlations to evaluate the role of DOM in the environmental fate of Hg, especially in field investigations of the spatial and temporal distribution of Hg, the properties of DOM must be taken into account.
Assuntos
Monitoramento Ambiental , Mercúrio/análise , Carbono , Corantes , Fluorescência , Lagos , Compostos OrgânicosRESUMO
Grain weight is one of the most important yield components and a developmentally complex structure comprised of two major compartments (endosperm and pericarp) in maize (Zea mays L.), however, very little is known concerning the coordinated accumulation of the numerous proteins involved. Herein, we used isobaric tags for relative and absolute quantitation (iTRAQ)-based comparative proteomic method to analyze the characteristics of dynamic proteomics for endosperm and pericarp during grain development. Totally, 9539 proteins were identified for both components at four development stages, among which 1401 proteins were non-redundant, 232 proteins were specific in pericarp and 153 proteins were specific in endosperm. A functional annotation of the identified proteins revealed the importance of metabolic and cellular processes, and binding and catalytic activities for the tissue development. Three and 76 proteins involved in 49 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were integrated for the specific endosperm and pericarp proteins, respectively, reflecting their complex metabolic interactions. In addition, four proteins with important functions and different expression levels were chosen for gene cloning and expression analysis. Different concordance between mRNA level and the protein abundance was observed across different proteins, stages, and tissues as in previous research. These results could provide useful message for understanding the developmental mechanisms in grain development in maize.
Assuntos
Proteoma , Proteômica , Zea mays/metabolismo , Análise por Conglomerados , Biologia Computacional/métodos , Grão Comestível/citologia , Grão Comestível/crescimento & desenvolvimento , Grão Comestível/metabolismo , Endosperma/metabolismo , Proteínas de Plantas/metabolismo , Mapeamento de Interação de Proteínas , Proteômica/métodos , Sementes/crescimento & desenvolvimento , Sementes/metabolismo , Zea mays/citologia , Zea mays/crescimento & desenvolvimentoRESUMO
ADP-ribosylation factors (ARFs) are small GTP-binding proteins that regulate a wide variety of cell functions. Previously, we isolated a new ARF, ZmArf2, from maize (Zea mays). Sequence and expression characteristics indicated that ZmArf2 might play a critical role in the early stages of endosperm development. In this study, we investigated ZmArf2 function by analysis of its GTP-binding activity and subcellular localization. We also over-expressed ZmArf2 in Arabidopsis and measured organ and cell size and counted cell numbers. The expression levels of five organ size-associated genes were also determined in 35S::ZmArf2 transgenic and wild-type plants. Results showed that the recombinant ZmArf2 protein purified from Escherichia coli exhibited GTP-binding activity. Subcellular localization revealed that ZmArf2 was localized in the cytoplasm and plasma membrane. ZmArf2 over-expression in Arabidopsis showed that 35S::ZmArf2 transgenic plants were taller and had larger leaves and seeds compared to wild-type plants, which resulted from cell expansions, not an increase in cell numbers. In addition, three cell expansion-related genes, AtEXP3, AtEXP5 and AtEXP10, were upregulated in 35S::ZmArf2 transgenic lines, while the expression levels of AtGIF1 and AtGRF5, were unchanged. Collectively, our studies suggest that ZmArf2 has an active GTP-binding function, and plays a crucial role in growth and development in Arabidopsis through cell expansion mediated by cell expansion genes.
Assuntos
Fatores de Ribosilação do ADP/genética , Arabidopsis/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas , Sementes/crescimento & desenvolvimento , Zea mays/genética , Fatores de Ribosilação do ADP/metabolismo , Arabidopsis/citologia , Arabidopsis/genética , Crescimento Celular , Membrana Celular/metabolismo , Citoplasma/metabolismo , Genes Reporter , Folhas de Planta/citologia , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Sementes/citologia , Sementes/genética , Regulação para CimaRESUMO
Iron oxide (FeO) coated by natural organic matter (NOM) is ubiquitous. The associations of minerals with organic matter (OM) significantly changes their surface properties and reactivity, and thus affect the environmental fate of pollutants, including nutrients (e.g., phosphorus (P)). In this study, ferrihydrite/goethite-humic acid (FH/GE-HA) complexes were prepared and their adsorption characteristics on P at various pH and ionic strength were investigated. The results indicated that the FeO-OM complexes showed a decreased P adsorption capacity in comparison with bare FeO. The maximum adsorption capacity (Qmax) decreased in the order of FH (22.17 mg/g)>FH-HA (5.43 mg/g)>GE (4.67 mg/g)>GE-HA (3.27 mg/g). After coating with HA, the amorphous FH-HA complex still showed higher P adsorption than the crystalline GE-HA complex. The decreased P adsorption observed might be attributed to changes of the FeO surface charges caused by OM association. The dependence of P adsorption on the specific surface area of adsorbents suggests that the FeO component in the complexes is still the main contributor for the adsorption surfaces. The P adsorptions on FeO-HA complexes decreased with increasing initial pH or decreasing initial ionic strength. A strong dependence of P adsorption on ionic strength and pH may demonstrate that outer-sphere complexes between the OM component on the surface and P possibly coexist with inner-sphere surface complexes between the FeO component and P. Therefore, previous over-emphasis on the contributions of original minerals to P immobilization possibly over-estimates the P loading capacity of soils, especially in humic-rich areas.
Assuntos
Compostos Férricos/química , Modelos Químicos , Fósforo/química , Poluentes do Solo/química , Adsorção , Substâncias Húmicas , Concentração de Íons de Hidrogênio , Compostos de Ferro , Minerais , Solo/química , Propriedades de SuperfícieRESUMO
Magnetosome produced by Magnetospirillum AMB-1 is highly crystalline, monodisperse, bioengineerable and a better nanomagnetic material candidate for a broad range of applications, ranging from medicine, biology and electronics to aerospace engineering. Many efforts have been made to get the optimal growth conditions and improve the accumulation of magnetosome. Studies have showed that oxygen concentration is a key factor to the formation of magnetosome. The effects of various of reducing agents in different concentrations on the growth of Magnetospirillum AMB-1 and the corresponding magnetosome formation have been examined in our study. The results show that the growth of the bacterial cells and the synthesis of magnetosome are both influenced in the presence of different concentrations of reducing agents.
RESUMO
Background: Previous clinical randomized controlled trials (RCTs) have demonstrated that immune checkpoint inhibitors (ICIs) cause various toxicities during cancer treatment, but the effects of different inhibitors in combination with chemotherapy for cardiotoxicity remain controversial. The aim of the present study was to assess cardiotoxicity caused by programmed cell death protein 1 (PD-1), programmed cell death-Ligand 1 (PD-L1), and cytotoxic T lymphocyte associate protein-4 (CTLA-4) in combination with chemotherapy to treat lung cancer. Methods: The following ICIs were included in the present study: durvalumab, avelumab, ipilimumab, atezolizumab, pembrolizumab, cemiplimab, and nivolumab. The relevant information was extracted using a predefined data extraction table, and the risk of bias was assessed in randomized controlled trials using the Cochrane Bias Risk tool. The main outcomes were hypertension, heart failure, pericardial effusion, and other adverse cardiac events. The random effects model was used to conduct a paired meta-analysis, and a random effects network meta-analysis was then performed within a Bayesian framework. Results: In total, 17 RCTs were included in the present study. There were 11,063 individuals in the experimental and control groups, with an average age greater than 60 years. Based on the evaluation of all drug classes in RCTs, CTLA-4+chemotherapy (RR, -0.69 [95% CI, 2.91-1.52] and PD-L1 (RR, -0.21 [95% CI, -1.03-0.60]) were less cardiotoxic than the control arm, which indicated they were safer options for adverse cardiac events. PD-L1 alone was less cardiotoxic than PD-1 alone (RR, -0.57 [95% CI, -1.96-0.82]). Further, the dual immunotarget inhibitor, PD-1+CTLA-4, had the lowest SUCRA value and had the highest cardiotoxicity (SUCRA=9). Conclusion: When classified according to drug type, CTLA-4+chemotherapy is associated with fewer cardiac adverse events compared to other treatments. Dual immunotarget inhibitors are more likely to have adverse cardiac reactions. Therefore, clinicians should consider this evidence when developing an ICI immunotherapy regimen for lung cancer. Systematic review registration: https://www.crd.york.ac.uk/prospero, identifier CRD42023360931.
RESUMO
PURPOSE: Through meta-analysis, we aimed to assess the efficacy and safety of drug-coated balloons (DCB), compared with drug-eluting stents (DES) or uncoated devices, in the treatment of de novo coronary lesions. MATERIALS AND METHODS: Only randomized controlled trials were included. The primary outcomes were late lumen loss (LLL), target lesion revascularization (TLR), and major adverse cardiac events (MACEs). Subgroup analyses were conducted based on clinical indications, whether DCBs were used with a systematic or bailout stent, and types of DESs. RESULTS: The present meta-analysis demonstrated that DCBs elicit significantly lower incidences of TLR, MACE, and LLL, compared with uncoated devices, and similar incidences, compared with DESs, in the treatment of de novo coronary lesions. Subgroup analysis indicated that DCBs used with a bailout stent achieved lower incidences of binary restenosis and myocardial infarction, compared with uncoated devices, and provided less LLL than DESs. DCBs showed similar rates of TLR and MACE, with significantly less LLL, than DESs in treating de novo small-vessel diseases. The clinical efficacy of DCBs was similar to that of second-generation DES. CONCLUSION: Overall, DCB is favored over bare metal stent alone in treating de novo coronary lesions. DCBs appear to be a promising alternative to DESs in the treatment of de novo coronary lesions.
Assuntos
Vasos Coronários , Coração , Humanos , Ensaios Clínicos Controlados Aleatórios como Assunto , ClorobenzenosRESUMO
We wished to elucidate a potential role of the tumor necrosis factor-like weak inducer of apoptosis (TWEAK)/fibroblast growth factor-inducible molecule 14 (Fn14) axis in myocardial fibrosis. Stimulation of neonatal rat cardiac fibroblasts (CFs) with TWEAK could increase CFs numbers and collagen synthesis. Conversely, when CFs were pretreated with siRNA against Fn14, induction of cell proliferation and collagen synthesis by TWEAK were inhibited. Pretreatment with TWEAK on CFs induced activation of the nuclear factor-kappaB (NF-кB) pathway and subsequently increased the production of metalloproteinase-9 (MMP-9). Cell treatment with siRNA against Fn14 led to inhibition of the NF-кB pathway. Additionally, after stimulation of cell with ammonium pyrrolidine dithiocarbamate, cell proliferation and collagen synthesis induced by NF-кB and the upregulation of MMP-9 production were inhibited. The present study suggested that the TWEAK/Fn14 axis increased cell proliferation and collagen synthesis by activating the NF-кB pathway and increasing MMP-9 activity. This axis may be important for regulating myocardial fibrosis.
Assuntos
Proteínas Reguladoras de Apoptose/metabolismo , Colágeno/biossíntese , Fibroblastos/metabolismo , Proteínas de Membrana/metabolismo , Miocárdio/metabolismo , NF-kappa B/metabolismo , Receptores do Fator de Necrose Tumoral/metabolismo , Transdução de Sinais , Fatores de Necrose Tumoral/metabolismo , Animais , Proliferação de Células , Colágeno/genética , Citocina TWEAK , Metaloproteinase 9 da Matriz/biossíntese , RNA Mensageiro/metabolismo , Ratos , Receptor de TWEAKRESUMO
In order to effectively assess all types of security risks in the important event, the important decision-making basis for security risk warning and emergency management of important event is provided by analyzing the coupling relationship and evolution mechanism between various risks. The criminal causes, management defects, security and emergency system construction are analyzed from the possibility of accidents and risks. The multi-source data risk assessment system based on five subsystems and its index set of human factors, management factors, site factors, event factors and audit factors are proposed. The weight of each index in the assessment system is determined by the method of information entropy, and then the risk grade of important event is determined according to the weight calculation function and the improved fuzzy matter element model. The verification with an example shows that: the risk assessment model is optimized by combining entropy weight with fuzzy matter-element model, the influence of weight data extreme value was weakened, the qualitative description and quantitative analysis of multi-source data could be combined, and the subjective error was reduced. The risk grade of important event is reasonably evaluated, and the assessment effect is basically consistent with the expert inspection analysis, which shows that the method had certain application value.
Assuntos
Medição de Risco , Entropia , HumanosRESUMO
The right coronary artery (RCA) originating from the left anterior descending artery (LAD) is a very rare variation of coronary artery anomaly. This kind of anomaly is usually considered to be clinically benign. Here, we present an acute myocardial infarction patient with a single coronary artery (SCA), in whom the LAD and RCA are both occlusive at the same time. He suffered from ventricular fibrillation, cardiogenic shock, and severe bradyarrhythmias many times. Fortunately, this patient survived from death through our effective medical procedures.
RESUMO
Background and Purpose: The aim of this study was to explore the effect of half a year of evolocumab plus moderate-intensity statin treatment on carotid intraplaque neovascularization (IPN) and blood lipid levels. Methods: A total of 31 patients with 33 carotid plaques who received evolocumab plus statin treatment were included. Blood lipid levels, B-mode ultrasound and contrast-enhanced ultrasonography (CEUS) at baseline and after half a year of evolocumab plus statin therapy were collected. The area under the curve (AUC) reflected the total amount of acoustic developer entering the plaque or lumen within the 180 s measurement period. The enhanced intensity reflected the peak blood flow intensity during the monitoring period, and the contrast agent area reflected the area of vessels in the plaques. Results: Except for high-density lipoprotein cholesterol (HDL-c), all other lipid indices decreased. Compared with baseline, low-density lipoprotein cholesterol (LDL-c) decreased by approximately 57% (p < 0.001); total cholesterol (TC) decreased by approximately 34% (p < 0.001); small dense low-density lipoprotein (sd-LDL) decreased by approximately 52% (p < 0.001); and HDL-c increased by approximately 20% (p < 0.001). B-mode ultrasonography showed that the length and thickness of the plaque and the hypoechoic area ratio were reduced (p < 0.05). The plaque area, calcified area ratio, and lumen cross-sectional area changed little (p > 0.05). CEUS revealed that the area under the curve of plaque/lumen [AUC (P/L)] decreased from 0.27 ± 0.13 to 0.19 ± 0.11 (p < 0.001). The enhanced intensity ratio of plaque/lumen [intensity ratio (P/L)] decreased from 0.37 ± 0.16 to 0.31 ± 0.14 (p = 0.009). The contrast agent area in plaque/area of plaque decreased from 19.20 ± 13.23 to 12.66 ± 9.59 (p = 0.003). The neovascularization score decreased from 2.64 ± 0.54 to 2.06 ± 0.86 (p < 0.001). Subgroup analysis based on statin duration (<6 months and ≥6 months) showed that there was no significant difference in the AUC (P/L) or intensity ratio (P/L) at baseline or after half a year of evolocumab treatment. Conclusion: This study found that evolocumab combined with moderate-intensity statins significantly improved the blood lipid profile and reduced carotid IPN. Clinical Trial Registration: https://www.clinicaltrials.gov; identifier: NCT04423406.
RESUMO
Polyphenols from the leaves of sea buckthorn (Hippophae rhamnoides L.) are nutritious and bioactive substances that can be used as nutritional supplements. To improve their stability and bioaccessibility in vivo, chemical extracts of sea buckthorn leaves were, for the first time, encapsulated using electrohydrodynamic technology. The microcapsules were characterized using scanning electron microscopy, Fourier-transform infrared spectroscopy, and thermogravimetric analysis. The extract and microcapsules were evaluated for total phenols and flavonoids, total antioxidant activity, and their inhibitory effects on metabolic syndrome-related enzymes (α-glucosidase, α-amylase, and pancreatic lipase) under in vitro simulated digestion. The results indicated that the extract was successfully encapsulated; encapsulation protected polyphenols and flavonoids from degradation and increase their bioaccessibility in the intestine. The antioxidant activity and the inhibition of metabolic syndrome-related enzymes were better reserved after encapsulation. Our findings will help in promoting the potential of sea buckthorn as a nutritional supplement and expanding its commercial use.
Assuntos
Hippophae , Antioxidantes , Flavonoides , Frutas/química , Fenóis/análise , Extratos VegetaisRESUMO
A full-length cDNA encoding a maize GTP-binding protein of the ADP-ribosylation factor family was cloned by suppression subtractive hybridization and an in silico cloning approach. The cDNA was 938 bp in length and contained a complete ORF of 612 bp, which encodes a protein of 203 amino acid residues. Its deduced amino acids sequence had an 83% identity with that of a GTP-binding protein in rice. The gene was designated ZmArf2. The ZmArf2 gene consists of G1, G2, G3, G4 and G5 boxes, and Switch I and Switch II regions. Eight nucleotides differed and five amino acids changed between the popcorn inbred N04 and the dent corn inbred Dan232. One changed amino acid was in the G1 box. RT-PCR analysis showed that ZmArf2 expression increased in the early stages of endosperm development and was not tissue-specific.
Assuntos
Fatores de Ribosilação do ADP/genética , Zea mays/genética , Fatores de Ribosilação do ADP/análise , Fatores de Ribosilação do ADP/isolamento & purificação , Sequência de Aminoácidos , Sequência de Bases , Clonagem Molecular , Perfilação da Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Dados de Sequência Molecular , Filogenia , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , Zea mays/crescimento & desenvolvimentoRESUMO
Agricultural watersheds are a crucial contributor of terrestrial dissolved organic matter (DOM) for the adjacent aquatic environment. Recently, ecological engineering of the buffer zone such as a rice-paddy field was established to reduce the export of nutrients and contaminants from a small agricultural watershed. However, the potential of the rice-paddy field to reduce the terrestrial signature of DOM is unclear. Therefore, two small agricultural sub-catchments (i.e., sub-1 and sub-2) with different land uses and hill slope angles in the Three Gorges Reservoir (TGR) area of China were studied from 2014 to 2015. The results showed that the terrestrial DOM signals are indicated by optical indices (SUVA254, SR, fluorescence index) in the steeper and more forest covered, but rice-paddy field buffered sub-catchment (i.e., sub-2) decreased significantly, as compared to the reference sub-catchment (i.e., sub-1). Regardless of seasonal variations, the rice-paddy field retained a buffering role to reduce the terrestrial property of DOM and the highest capacity was observed during the rice-growth period. However, during storm events, the differences of DOM properties for two sub-catchments were not significant, because the buffer system was weakened. Finally, environmental implications of the role of such a buffer zone in the TGR areas are discussed. These results demonstrate that rice-paddy fields are successful in mitigating the terrestrial property of exported DOM, but the weaker performance during storm events still needs to be considered.
Assuntos
Oryza/metabolismo , Poluentes Químicos da Água/análise , Agricultura , China , Fluorescência , Florestas , Estações do Ano , Espectrometria de FluorescênciaRESUMO
Dissolved organic matter (DOM) is a crucial driver of various biogeochemical processes in aquatic systems. Thus, many lakes and streams have been investigated in the past several decades. However, fewer studies have sought to understand the changes in DOM characteristics in the waters of the Three Gorges Reservoir (TGR) areas, which are the largest artificial reservoir areas in the world. Thus, a field investigation of dissolved organic carbon (DOC) concentrations and of chromophoric dissolved organic matter (CDOM) properties was conducted from 2013 to 2015 to track the spatial-temporal variability of DOM properties in the TGR areas. The results showed that the alternations of wet and dry periods due to hydrological management have a substantial effect on the quantity and quality of aquatic DOM in TGR areas. Increases in DOC concentrations in the wet period show an apparent "dilution effect" that decreases CDOM compounds with relatively lower aromaticity (i.e., SUVA254) and molecular weight (i.e., SR). In contrast to the obvious temporal variations of DOM, significant spatial variability was not observed in this study. Additionally, DOM showed more terrigenous characteristics in the dry period but weak terrigenous characteristics in the wet period. Furthermore, the positive correlation between SUVA254 and CDOM suggests that the aromatic component controls the CDOM dynamics in TGR areas. The first attempt to investigate the DOM dynamics in TGR areas since the Three Gorges Dam was conducted in 2012, and the unique patterns of spatial-temporal variations in DOM that are highlighted in this study might provide a new insight for understanding the role of DOM in the fates of contaminants and may help in the further management of flow loads and water quality in the TGR area.
RESUMO
Accumulating evidence has shown that podocyte apoptosis is of vital importance for the development of glomerulosclerosis and progressive loss of renal function. However, the molecular mechanisms leading to podocyte apoptosis are still elusive. In this study, we investigated the role of estrogen-related receptor (ERR) γ in podocyte apoptosis, as well as the underlying mechanisms. Treatment of PAN caused a dose- and time-dependent podocyte apoptosis in line with a significant downregulation of ERRγ. Interestingly, the occurrence of ERRγ downregulation appeared earlier than the onset of cell apoptosis, suggesting a potential that ERRγ reduction triggered apoptotic response in podocyte. To test this hypothesis, ERRγ siRNA was administered to the podocytes. Strikingly, ERRγ silencing resulted in a significant cell apoptosis accompanied with increased injury markers of B7-1 and cathepsin L and decreased podocyte protein nephrin. In contrast, overexpression of ERRγ remarkably attenuated PAN-induced cell apoptosis. Moreover, ERRγ overexpression stimulated PI3K/Akt signaling pathway evidenced by increased expression of PI3K subunits p85α and p110α and phosphorylated Akt. Importantly, a specific PI3K inhibitor LY294002 entirely reversed the anti-apoptotic effect of ERRγ following PAN treatment. Finally, we observed a striking downregulation of ERRγ in PAN-treated rat kidneys, suggesting that our cell model replicated the in vivo condition. Taken together, these data highly suggested that ERRγ played a novel role in modulating podocyte apoptosis by targeting PI3K/Akt signaling pathway.