RESUMO
River water quality is influenced by natural processes and human activities. Multi-scale landscape patterns can affect river water quality by altering the generation and transport processes of pollutants at different spatial scales. Taking Taizi River Basin in Northeast China as an example, we analyzed the relationship between landscape patterns and non-point source pollution in rivers based on water quality monitoring data and land use data by using correlation analysis and redundancy analysis methods. We aimed to determine the key spatial scales for the responses of landscape patterns to non-point source pollution and identify the key landscape indices influencing river non-point source pollution. The results showed that water quality of Taizi River Basin had seasonal differences, with better water quality during the flood season than non-flood season. Spatially, total nitrogen (TN) and total phosphorus (TP) were higher at the confluence points of tributaries and downstream areas. The impact of landscape patterns on non-point source pollution was stronger during the non-flood season than the flood season, while the influence on TN was stronger than on TP. At the spatial scale of within 500 m buffer zone during the flood season and at the sub-watershed scale during the non-flood season, landscape patterns showed the highest explanatory power for the variations of TN and TP. At the type level, built-up land, cropland, and bare land were positively correlated with TN and TP, while forest was negatively correlated with TN and TP, which were the key types influencing non-point source pollution. At the landscape level, patch density, percentage of like adjacencies, and contagion index were key indicators affecting watershed water quality. Lower patch density was associated with better connectivity and aggregation of "sink" landscapes, leading to better purification effects on TN, but more pronounced retention effects on TP. Conversely, higher landscape diversity and denser pattern of multiple types would cause the deterioration of water quality. Our results suggested that rational allocation of landscape types within the watershed and riparian buffer zones, appropriately enriching landscape diversity, and optimizing landscape aggregation and connectivity would be effective measures for improving water quality and achieving sustainable ecological management.
Assuntos
Monitoramento Ambiental , Fósforo , Rios , Poluentes Químicos da Água , China , Rios/química , Monitoramento Ambiental/métodos , Poluentes Químicos da Água/análise , Fósforo/análise , Ecossistema , Nitrogênio/análise , Poluição Difusa/análise , Poluição Difusa/prevenção & controle , Qualidade da Água , Análise EspacialRESUMO
Based on the concentration data of seven heavy metal elements[As, Cd, Cu, Pb, Hg, Ni, and Cr(â ¥)] in the surface soil of a typical industrial park in northwest China, the characteristics of heavy metal pollution in the industrial park were analyzed, and the ecological risk and pollution were evaluated using the potential ecological risk index and the index of geo-accumulation. The positive matrix factorization (PMF) model and random forest (RF) model were used for quantitative source analysis, and the emission data of sampling enterprises and empirical data of the source emission component spectrum were combined to identify the characteristic elements and determine the emission source category. The results showed that the heavy metals at all sampling points in the park did not exceed the second-class screening value of construction land in the soil pollution risk control standard for construction land (GB 36600-2018). However, compared with the local soil background values, five elements, excluding As and Cr, were enriched in different degrees, presenting slight pollution and moderate ecological risk (RI=250.04). Cd and Hg were the main risk elements of the park. The results of source analysis showed that the five main sources of pollution were fossil fuel combustion and chemical production sources (33.73%, 9.71%, total source contribution rate of PMF and RF, respectively; the same below), natural sources and waste residue landfill (32.40%, 40.80%), traffic emissions (24.49%, 48.08%), coal burning and non-ferrous metal smelting (5.43%, 0.11%), and electroplating and ore smelting (3.95%, 1.30%). The simulation R2 of the total variable of the two models were above 0.96, indicating that the models could predict heavy metals well. However, considering the actual situation of the number of enterprises in the park and roading density, the main pollution sources of soil heavy metals in the park should be industrial sources, and the simulation results of the PMF model were closer to the actual situation in the park.
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The Chinese razor clam (Sinonovacula constricta) is an important for Chinese aquaculture marine bivalve that naturally occurs across intertidal and estuarine areas subjected to significant changes in salinity level. However, the information on the molecular mechanisms related to high salinity stress in the species remain limited. In this study, nine gill samples of S. constricta treated with 20, 30, and 40 ppt salinity for 24 h were used for whole-transcriptome RNA sequencing, and a regulatory network of competing endogenous RNAs (ceRNAs) was constructed to better understand the mechanisms responsible for adaptation of the species to high salinity. A total of 83,262 lncRNAs, 52,422 mRNAs, 2890 circRNAs, and 498 miRNAs were identified, and 4175 of them displayed differential expression pattern among the three groups examined. The KEGG analyses of differentially expressed RNAs evidenced that amino acid synthesis and membrane transport were the dominant factors involved in the adaptation of the Chinese razor clam to acute salinity increase, while lipid metabolism and signaling played only a supporting role. In addition, lncRNA/circRNA-miRNA-mRNA regulatory networks (ceRNA network) showed clearly regulatory relationships among different RNAs. Moreover, the expression of four candidate genes, including tyrosine aminotransferase (TAT), hyaluronidase 4 (HYAL4), cysteine sulfinic acid decarboxylase (CSAD), and ∆1-pyrroline-5-carboxylate synthase (P5CS) at different challenge time were detected by qRT-PCR. The expression trend of TAT and HYAL4 was consistent with that of the ceRNA network, supporting the reliability of established network. The expression of TAT, CSAD, and P5CS were upregulated in response to increased salinity. This might be associated with increased amino acid synthesis rate, which seems to play an essential role in adaptation of the species to high salinity stress. In contrast, the expression level of HYAL4 gene decreased in response to elevated salinity level, which is associated with reduction Hyaluronan hydrolysis to help maintain water in the cell. Our findings provide a very rich reference for understanding the important role of ncRNAs in the salinity adaptation of shellfish. Moreover, the acquired information may be useful for optimization of the artificial breeding of the Chinese razor clam under aquaculture conditions.
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To explore the differences in pollution characteristics, sources, and health risks of PM2.5 carrier metals in urban and suburban areas in Beijing, daily PM2.5 samples were collected from Haidian and Daxing from June to November 2017 and the concentration of PM2.5 and 13 constituent metals were analyzed. The sources of these 13 metal elements were analyzed by positive matrix factorization (PMF), and the health hazards of a subset of 9 metals were evaluated using health risk assessment. The results showed that the concentrations of PM2.5 and 10 metal concentrations in the urban area including Cr, Co, Mn, and Ni were significantly different from those in suburban areas (P<0.05). The source analysis results show four key sources, although their relative contributions vary slightly between urban and rural areas. In urban areas, the main sources are motor vehicles (51.2%), coal burning (19.1%), dust (19.3%), and fuel oil (10.4%); in the suburbs, sources are motor vehicles (47.9%), coal burning (22.6%), dust (20.2%), and electroplating (9.3%). The results of the health risk assessment showed that all metal HQ values in the suburbs were less than 1, and there was no non-carcinogenic risk. Ni and Pb in urban areas, and Cd, Co, Ni, and Pb in suburban areas, do not present a cancer risk, while the R values of As (2.77×10-5), Cd (2×10-6), Co (1.76×10-6), and Cr(â ¥) (7.88×10-6) in urban areas and As (8.34×10-6) and Cr(â ¥) (4.94×10-6) in suburban areas present some risk of cancer.
Assuntos
Poluentes Atmosféricos , Metais Pesados , Poluentes Atmosféricos/efeitos adversos , Poluentes Atmosféricos/análise , Pequim , China , Carvão Mineral , Poeira/análise , Monitoramento Ambiental , Metais Pesados/análise , Material Particulado/análise , Medição de RiscoRESUMO
Dissolved organic matter (DOM) is an essential factor in natural waters to affect the bioavailability of hydrophobic organic compounds (HOCs). Climate warming may influence the partition of HOCs between DOM and water as well as the physiology of organisms. Thus, we hypothesized that elevated temperature might affect the bioavailability of HOCs in the presence of DOM. To test this hypothesis, the effect of temperature on the bioavailability of pyrene to Daphnia magna (D. magna) in water-DOM (fulvic acid) system was investigated. The results showed that, although the concentration of freely dissolved pyrene increased slightly with temperature in the presence of DOM when the level of total dissolved pyrene was kept constant, D. magna immobilization (increased by 50.0-167%) and internal body burden of pyrene (increased by 18.4-41.5%) increased significantly with every 4 °C increase in temperature (16, 20, 24 °C). The main reasonable explanation for this result is that elevated temperature promoted pyrene uptake by D. magna. It was found that the increase percentage of 1-hydroxypyrene (main metabolite of pyrene) concentrations with temperature was higher than that of pyrene concentrations in the body except gut of D. magna. This result indicated that increased temperature might enhance the metabolic rates of D. magna, thus leading to increased uptake rate of freely dissolved and DOM-associated pyrene. This study suggests that elevated temperature might enhance the bioavailability of HOCs in natural waters through influencing both the bioavailable fraction of HOCs and their uptake rates in aquatic organisms, and this should be considered for evaluating their eco-environmental risks under the context of climate warming.
Assuntos
Daphnia , Poluentes Químicos da Água/análise , Animais , Disponibilidade Biológica , Pirenos/análise , TemperaturaRESUMO
Teosinte branched1/cycloidea/proliferating (TCP) transcription factors play a broad role in plant growth and development, but their involvement in the regulation of anthocyanin biosynthesis is currently unclear. In this study, anthocyanin biosynthesis induced by different light intensities in apple (Malus domestica) was found to be largely dependent on the functions of the MdMYB1 and MdTCP46 transcription factors. The expression of MdTCP46 was responsive to high light intensity, and under these conditions it promoted anthocyanin biosynthesis by direct interactions with MdMYB1 that enhanced the binding of the latter to its target genes. MdTCP46 also interacted with a bric-a-brac/tramtrack/broad (BTB) protein, MdBT2, that is responsive to high light intensity, which ubiquitinated MdTCP46 and mediated its degradation via the 26S proteasome pathway. Our results demonstrate that the dynamic regulatory module MdBT2-MdTCP46-MdMYB1 plays a key role in modulating anthocyanin biosynthesis at different light intensities in apple, and provides new insights into the post-transcriptional regulation of TCP proteins.
Assuntos
Malus , Antocianinas , Frutas/metabolismo , Regulação da Expressão Gênica de Plantas , Malus/genética , Malus/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismoRESUMO
As an important environment factor, light affects plant growth and development throughout life. B-BOX (BBX) proteins play key roles in the regulation of light signaling. Although the multiple roles of BBX proteins have been extensively studied in Arabidopsis, the research in apple is much less extensive. In this study, we systematically characterized the negative role of an apple BBX protein MdBBX37 in light signaling, including inhibiting anthocyanin biosynthesis and promoting hypocotyl elongation. We found that MdBBX37 interacted with MdMYB1 and MdMYB9, two key positive regulators of anthocyanin biosynthesis, and inhibited the binding of those two proteins to their target genes and, therefore, negatively regulated anthocyanin biosynthesis. In addition, MdBBX37 directly bound to the promoter of MdHY5, a positive regulator of light signaling, and suppressed its expression, and thus relieved MdHY5-mediated hypocotyl inhibition. Taken together, our investigations suggest that MdBBX37 is a negative regulator of light signaling in apple. Our study will provide reference for further study on the functions of BBX proteins in apple.
Assuntos
Antocianinas/biossíntese , Genes de Plantas , Hipocótilo/metabolismo , Malus/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Sequência de Aminoácidos , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Transporte , Ritmo Circadiano , Regulação da Expressão Gênica de Plantas , Luz , Malus/crescimento & desenvolvimento , Malus/metabolismo , Morfogênese/fisiologia , Desenvolvimento Vegetal/genética , Plantas Geneticamente Modificadas/genética , Regiões Promotoras Genéticas , Alinhamento de Sequência , Fatores de Transcrição/metabolismoRESUMO
Drought stress induces anthocyanin biosynthesis in many plant species, but the underlying molecular mechanism remains unclear. Ethylene response factors (ERFs) play key roles in plant growth and various stress responses, including affecting anthocyanin biosynthesis. Here, we characterized an ERF protein, MdERF38, which is involved in drought stress-induced anthocyanin biosynthesis. Biochemical and molecular analyses showed that MdERF38 interacted with MdMYB1, a positive modulator of anthocyanin biosynthesis, and facilitated the binding of MdMYB1 to its target genes. Therefore, MdERF38 promoted anthocyanin biosynthesis in response to drought stress. Furthermore, we found that MdBT2, a negative modulator of anthocyanin biosynthesis, decreased MdERF38-promoted anthocyanin biosynthesis by accelerating the degradation of the MdERF38 protein. In summary, our data provide a mechanism for drought stress-induced anthocyanin biosynthesis that involves dynamic modulation of MdERF38 at both transcriptional and post-translational levels.
Assuntos
Antocianinas/metabolismo , Etilenos/metabolismo , Malus/fisiologia , Reguladores de Crescimento de Plantas/metabolismo , Fatores de Transcrição/metabolismo , Secas , Malus/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Fatores de Transcrição/genéticaRESUMO
MYB transcription factors (TFs) have been demonstrated to play diverse roles in plant growth and development through interaction with basic helix-loop-helix (bHLH) TFs. MdbHLH33, an apple bHLH TF, has been identified as a positive regulator in cold tolerance and anthocyanin accumulation by activating the expressions of MdCBF2 and MdDFR. In the present study, a MYB TF MdMYB308L was found to also positively regulate cold tolerance and anthocyanin accumulation in apple. We found that MdMYB308L interacted with MdbHLH33 and enhanced its binding to the promoters of MdCBF2 and MdDFR. In addition, an apple RING E3 ubiquitin ligase MYB30-INTERACTING E3 LIGASE 1 (MdMIEL1) was identified to be an MdMYB308L-interacting protein and promoted the ubiquitination degradation of MdMYB308L, thus negatively regulated cold tolerance and anthocyanin accumulation in apple. These results suggest that MdMYB308L acts as a positive regulator in cold tolerance and anthocyanin accumulation in apple by interacting with MdbHLH33 and undergoes MdMIEL1-mediated protein degradation. The dynamic change in MYB-bHLH protein complex seems to play a key role in the regulation of plant growth and development.
Assuntos
Adaptação Fisiológica , Antocianinas , Malus , Proteínas de Plantas , Fatores de Transcrição , Adaptação Fisiológica/genética , Antocianinas/metabolismo , Regulação da Expressão Gênica de Plantas , Malus/enzimologia , Malus/genética , Proteínas de Plantas/metabolismo , Fatores de Transcrição/metabolismo , Ubiquitina-Proteína Ligases/metabolismoRESUMO
Wounding stress leads to anthocyanin accumulation. However, the underlying molecular mechanism remains elusive. In this study, MdWRKY40 was found to promote wounding-induced anthocyanin biosynthesis in association with MdMYB1 and undergo MdBT2-mediated degradation in apple. We found that MdMYB1, a positive regulator of anthocyanin biosynthesis, was essential for the wounding-induced anthocyanin biosynthesis in apple. MdWRKY40 was identified as an MdMYB1-interacting protein, and enhanced the binding of MdMYB1 to its target genes in response to wounding. We found that MdBT2 interacted physically with MdWRKY40 and was involved in its degradation through the 26S proteasome pathway. Our results demonstrate that MdWRKY40 is a key modulator in the wounding-induced anthocyanin biosynthesis, which provides new insights into the regulation of wounding-induced anthocyanin biosynthesis at both the transcriptional and post-translational levels in apple.
Assuntos
Antocianinas/biossíntese , Malus/metabolismo , Proteínas de Plantas/metabolismo , Proteólise , Vias Biossintéticas/genética , Regulação da Expressão Gênica de Plantas , Malus/genética , Modelos Biológicos , Ligação Proteica , Biossíntese de Proteínas , Estabilidade Proteica , Ativação Transcricional/genéticaRESUMO
The molecular mechanism of leaf senescence in apple (Malus domestica) is still not fully understood. We used gene expression analysis and protein-protein interactions to decipher the relationships of abscisic acid (ABA) and two proteins, MdbHLH93 and MdBT2, in the senescence process. We found that MdbHLH93 promoted leaf senescence and the expression of senescence-related genes, which exhibited similar effects to ABA on leaf senescence. MdbHLH93 activated directly the transcription of MdSAG18. We also found that an ABA-responsive protein, MdBT2, interacted directly with MdbHLH93, and induced the ubiquitination and degradation of the MdbHLH93 protein, and thus delayed leaf senescence. Our findings provide new insights into the regulatory network of leaf senescence through the functional interactions among ABA, MdbHLH93 and MdBT2.
Assuntos
Ácido Abscísico/farmacologia , Malus/metabolismo , Folhas de Planta/crescimento & desenvolvimento , Proteínas de Plantas/metabolismo , Clorofila/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Genes de Plantas , Malus/efeitos dos fármacos , Malus/genética , Reguladores de Crescimento de Plantas/farmacologia , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/genética , Proteínas de Plantas/genética , Ligação Proteica/efeitos dos fármacos , Estabilidade Proteica , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Nicotiana/efeitos dos fármacos , Nicotiana/genética , Transcrição Gênica/efeitos dos fármacosRESUMO
The protein-like dissolved organic matter (DOM) is ubiquitous in aquatic environments. However, the bioavailability of protein-like DOM-associated hydrophobic organic compounds (HOCs) is not well-understood, and in particular, the direct evidence of their uptake by organisms is scarce. In the present work, tryptone (2000 Da), bovine serum albumin (BSA; 66â¯000 Da), and phycocyanin (120â¯000 Da) were chosen as model protein-like DOM, which were labeled by commercial fluorescein (cy5) to investigate the uptake mechanisms of protein compound-associated pyrene (a typical HOC) by Daphnia magna. The pyrene concentration in the tissues except the gut and immobilization of D. magna were detected to calculate the bioavailable fraction of protein compound-associated pyrene when the freely dissolved pyrene concentration was controlled through passive dosing devices. The results demonstrated that the tryptone could permeate cellular membrane and directly enter the tissues of D. magna from the exposure solutions, whereas BSA and phycocyanin might indirectly enter the tissues from the gut. A part of pyrene associated with protein compounds was bioavailable to D. magna; the order of their bioavailable fractions was trypone (54.6-58.1%) > phycocyanin (21.6-32.8%) > BSA (17.7-26.8%). The difference was principally related to the uptake mechanisms of pyrene associated with different types of protein. This work suggests that the protein compound-associated HOCs should be considered to evaluate the bioavailability and eco-environmental hazard of HOCs in natural waters.
Assuntos
Daphnia , Poluentes Químicos da Água , Animais , Disponibilidade Biológica , Compostos Orgânicos , PirenosRESUMO
Dissolved organic matter (DOM) is a key environmental factor for the bioavailability of hydrophobic organic compounds (HOCs) in natural waters. However, the bioavailability of DOM-associated HOCs is not clear. In this research, pyrene was selected as a model HOC, and its freely dissolved concentration (Cfree) was maintained by passive dosing systems. The immobilization and pyrene content in the tissues excluding gut of Daphnia magna were examined to quantify the bioavailability of DOM-associated pyrene. The results indicated that DOM promoted the bioavailability of pyrene when the Cfree of pyrene was kept constant, and the bioavailability of pyrene associated with DOM of various molecular weights was ordered as middle molecular weight (5â¯000-10â¯000 Da) DOM > lower molecular weight (<1â¯000, 1â¯000-3â¯000, and 3â¯000-5â¯000 Da) DOM > higher molecular weight (>10â¯000 Da) DOM. The influencing mechanisms of DOM molecular weight were related with the partition of pyrene between DOM and water, the uptake routes of DOM by D. magna, and the desorption or release of pyrene from DOM in the gut of D. magna. The findings obtained in this research suggest that the bioavailability of DOM-associated HOCs should be taken into account for the eco-environmental risk assessment of HOCs in water systems.