RESUMO
The extensive utilization of per- and polyfluoroalkyl substances (PFASs) has led to their pervasive presence in the environment, resulting in contamination of aquatic products. Prolonged exposure to PFASs has been linked to direct hepatic and renal damage, along with the induction of oxidative stress, contributing to a spectrum of chronic ailments. Despite the recent surge in popularity of red swamp crayfish as a culinary delicacy in China, studies addressing PFASs' exposure and associated health risks from their consumption remain scarce. To address this gap, our study investigated the PFASs' content in 85 paired edible tissue samples sourced from the five primary red swamp crayfish breeding provinces in China. The health risks associated with dietary exposure were also assessed. Our findings revealed widespread detection of PFASs in crayfish samples, with short-chain perfluoroalkyl carboxylic acids (PFCAs) exhibiting the highest concentrations. Notably, the total PFAS concentration in the hepatopancreas (median: 160 ng/g) significantly exceeded that in muscle tissue (5.95 ng/g), as did the concentration of every single substance. The hazard quotient of perfluorohexanesulfonic acid (PFHxS) via consuming crayfish during peak season exceeded 1. In this case, a potential total non-cancer health risk of PFASs, which is mainly from the hepatopancreas and associated with PFHxS, is also observed (hazard index>1). Thus, it is recommended to avoid consuming the hepatopancreas of red swamp crayfish. Greater attention should be paid to governance technology innovation and regulatory measure strengthening for short-chain PFASs.
Assuntos
Astacoidea , Fluorocarbonos , Poluentes Químicos da Água , Animais , China , Medição de Risco , Fluorocarbonos/análise , Poluentes Químicos da Água/análise , Humanos , Contaminação de Alimentos/análise , Monitoramento Ambiental/métodos , Ácidos Alcanossulfônicos/análise , Exposição Dietética/estatística & dados numéricos , Exposição Ambiental/estatística & dados numéricos , Hepatopâncreas/química , População do Leste AsiáticoRESUMO
Parabens (PBs) and triclosan (TCS) are commonly found in pharmaceuticals and personal care products (PPCPs). As a result, they have been extensively found in the environment, particularly in aquaculture operations. Red swamp crayfish (Procambarus clarkii) consumption has significantly risen in China. Nevertheless, the levels of PBs and TCS in this species and the associated risk to human dietary intake remain undisclosed. This study assessed the amounts of five PBs, i.e., methyl-paraben (MeP), ethyl-paraben (EtP), propyl-paraben (PrP), butyl-paraben (BuP) and benzyl-paraben (BzP), as well as TCS in crayfish taken from five provinces of the middle-lower Yangtze River. MeP, PrP and TCS showed the highest detection rates (hepatopancreas: 46-86 %; muscle: 63-77 %) since they are commonly used in PPCPs. Significantly higher levels of ∑5PBs (median: 3.69 ng/g) and TCS (median: 7.27 ng/g) were significantly found in the hepatopancreas compared to the muscle (median: 0.39 ng/g for ∑5PBs and 0.16 ng/g for TCS) (p < 0.05), indicating bioaccumulation of these chemicals in the hepatopancreas. The estimated daily intake values of ∑5PBs and TCS calculated from the median concentrations of crayfish were 6.44-7.94 ng/kg bw/day and 11.4-14.0 ng/kg bw/day, respectively. Although no health risk was predicted from consuming crayfish (HQ <1), consumption of the hepatopancreas is not recommended.
Assuntos
Astacoidea , Exposição Dietética , Parabenos , Triclosan , Poluentes Químicos da Água , Animais , Triclosan/análise , China , Poluentes Químicos da Água/análise , Parabenos/análise , Exposição Dietética/estatística & dados numéricos , Exposição Dietética/análise , Humanos , Medição de Risco , Distribuição Tecidual , Monitoramento Ambiental , Contaminação de Alimentos/análiseRESUMO
Stimulation of adult cardiomyocyte proliferation is a promising strategy for treating myocardial infarction (MI). Earlier studies have shown increased CCL2 levels in plasma and cardiac tissue both in MI patients and mouse models. In present study we investigated the role of CCL2 in cardiac regeneration and the underlying mechanisms. MI was induced in adult mice by permanent ligation of the left anterior descending artery, we showed that the serum and cardiac CCL2 levels were significantly increased in MI mice. Intramyocardial injection of recombinant CCL2 (rCCL2, 1 µg) immediately after the surgery significantly promoted cardiomyocyte proliferation, improved survival rate and cardiac function, and diminished scar sizes in post-MI mice. Alongside these beneficial effects, we observed an increased angiogenesis and decreased cardiomyocyte apoptosis in post-MI mice. Conversely, treatment with a selective CCL2 synthesis inhibitor Bindarit (30 µM) suppressed both CCL2 expression and cardiomyocyte proliferation in P1 neonatal rat ventricle myocytes (NRVMs). We demonstrated in NRVMs that the CCL2 stimulated cardiomyocyte proliferation through STAT3 signaling: treatment with rCCL2 (100 ng/mL) significantly increased the phosphorylation levels of STAT3, whereas a STAT3 phosphorylation inhibitor Stattic (30 µM) suppressed rCCL2-induced cardiomyocyte proliferation. In conclusion, this study suggests that CCL2 promotes cardiac regeneration via activation of STAT3 signaling, underscoring its potential as a therapeutic agent for managing MI and associated heart failure.
Assuntos
Insuficiência Cardíaca , Infarto do Miocárdio , Humanos , Camundongos , Animais , Ratos , Quimiocina CCL2/metabolismo , Infarto do Miocárdio/metabolismo , Miócitos Cardíacos , Insuficiência Cardíaca/metabolismo , Regeneração , Camundongos Endogâmicos C57BL , Apoptose , Fator de Transcrição STAT3/metabolismoRESUMO
OBJECTIVE: To investigate whether GRK4 regulates the phosphorylation and function of renal CCKBR. METHODS: GRK4 A142V transgenic mice were used as an animal model of enhanced GRK4 activity, and siRNA was used to silence the GRK4 gene to investigate the regulatory effect of GRK4 on CCKBR phosphorylation and function. Finally, the co-localization and co-connection of GRK4 and CCKBR in RPT cells were observed by laser confocal microscopy and immunoprecipitation to explore the mechanism of GRK4 regulating CCKBR. RESULTS: Gastrin infusion significantly increased urinary flow and sodium excretion rates in GRK4 WT mice (P < .05). GRK4 siRNA did not affect CCKBR protein expression in WKY RPT cells and SHR RPT cells, but remarkably reduced CCKBR phosphorylation in WKY and SHR RPT cells (P < .05). The inhibitory effect of gastrin on Na+-K+ -ATPase activity in WKY RPT cells was further enhanced by the reduction of GRK4 expression (P < .05), while GRK4 siRNA restored the inhibitory effect of gastrin on Na+-K+ -ATPase activity in SHR RPT cells. Laser confocal and Co-immunoprecipitation results showed that GRK4 and CCKBR co-localized in cultured RPT cells' cytoplasm. CONCLUSION: GRK4 participates in the development of hypertension by regulating the phosphorylation of renal CCKBR leading to impaired CCKBR function and water and sodium retention. Knockdown of GRK4 restored the function of CCKBR. The enhanced co-connection between GRK4 and CCKBR may be an important reason for the hyperphosphorylation of GRK4 and CCKBR involved in the pathogenesis of hypertension.
Assuntos
Hipertensão , Receptor de Colecistocinina B , Animais , Camundongos , Gastrinas/farmacologia , Hipertensão/genética , RNA Interferente Pequeno , Sódio , Adenosina TrifosfatasesRESUMO
This study aimed to develop a nomogram for predicting the progression-free survival (PFS) of testicular germ cell tumors (TGCT) patients based on DNA methylation signature and clinicopathological characteristics. The DNA methylation profiles, transcriptome data, and clinical information of TGCT patients were obtained from the Cancer Genome Atlas (TCGA) database. Univariate Cox, lasso Cox, and stepwise multivariate Cox regression were applied to identify a prognostic CpG sites-derived risk signature. Differential expression analysis, functional enrichment analysis, immunoinfiltration analysis, chemotherapy sensitivity analysis, and clinical feature correlation analysis were performed to elucidate the differences among risk groups. A prognostic nomogram integrating CpG sites-derived risk signature and clinicopathological features was further established and evaluated likewise. A risk score model based on 7 CpG sites was developed and found to exhibit significant differences among different survival, staging, radiotherapy, and chemotherapy subgroups. There were 1452 differentially expressed genes between the high- and low-risk groups, with 666 being higher expressed and 786 being lower expressed. Genes highly expressed were significantly enriched in immune-related biological processes and related to T-cell differentiation pathways; meanwhile, down-regulated genes were significantly enriched in extracellular matrix tissue organization-related biological processes and involved in multiple signaling pathways such as PI3K-AKT. As compared with the low-risk group, patients in the high-risk group had decreased lymphocyte infiltration (including T-cell and B-cell) and increased macrophage infiltration (M2 macrophages). They also showed decreased sensitivity to etoposide and bleomycin chemotherapy. Three clusters were obtained by consensus clustering analysis based on the 7 CpG sites and showed distinct prognostic features, and the risk scores in each cluster were significantly different. Multivariate Cox regression analysis found that the risk scores, age, chemotherapy, and staging were independent prognostic factors of PFS of TGCT, and the results were used to formulate a nomogram model that was validated to have a C-index of 0.812. Decision curve analysis showed that the nomogram model was superior to other strategies in the prediction of PFS of TGCT. In this study, we successfully established CpG sites-derived risk signature, which might serve as a useful tool in the prediction of PFS, immunoinfiltration, and chemotherapy sensitivity for TGCT patients.
Assuntos
Metilação de DNA , Neoplasias Embrionárias de Células Germinativas , Humanos , Metilação de DNA/genética , Intervalo Livre de Progressão , Fosfatidilinositol 3-Quinases/genética , Neoplasias Embrionárias de Células Germinativas/genéticaRESUMO
BACKGROUND AND AIMS: Cholesterol ester (CE) biosynthesis and homeostasis play critical roles in many cancers, including HCC, but their exact mechanistic contributions to HCC disease development require further study. APPROACH AND RESULTS: Here, we report on a proposed role of tumor suppressor P53 in its repressing ubiquitin-specific peptidase 19 (USP19) and sterol O-acyltransferase (SOAT) 1, which maintains CE homeostasis. USP19 enhances cholesterol esterification and contributes to hepatocarcinogenesis (HCG) by deubiquitinating and stabilizing SOAT1. Loss of either SOAT1 or USP19 dramatically attenuates cholesterol esterification and HCG in P53-deficient mice fed with either a normal chow diet or a high-cholesterol, high-fat diet (HCHFD). SOAT1 inhibitor avasimibe has more inhibitory effect on HCC progression in HCHFD-maintained P53-deficient mice when compared to the inhibitors of de novo cholesterol synthesis. Consistent with our findings in the mouse model, the P53-USP19-SOAT1 signaling axis is also dysregulated in human HCCs. CONCLUSIONS: Collectively, our findings demonstrate that SOAT1 participates in HCG by increasing cholesterol esterification, thus indicating that SOAT1 is a potential biomarker and therapeutic target in P53-deficient HCC.
Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Humanos , Animais , Camundongos , Esterificação , Carcinoma Hepatocelular/genética , Proteína Supressora de Tumor p53/genética , Neoplasias Hepáticas/genética , Colesterol , EndopeptidasesRESUMO
Heart failure with preserved ejection fraction (HFpEF) is highly prevalent, and lacks effective treatment. The aberration of WNT pathway underlies many pathological processes including cardiac fibrosis and hypertrophy, while porcupine is an acyltransferase essential for the secretion of WNT ligands. In this study we investigated the role of WNT signaling pathway in HFpEF as well as whether blocking WNT signaling by a novel porcupine inhibitor CGX1321 alleviated HFpEF. We established two experimental HFpEF mouse models, namely the UNX/DOCA model and high fat diet/L-NAME ("two-hit") model. The UNX/DOCA and "two-hit" mice were treated with CGX1321 (3 mg·kg-1·d-1) for 4 and 10 weeks, respectively. We showed that CGX1321 treatment significantly alleviated cardiac hypertrophy and fibrosis, thereby improving cardiac diastolic function and exercise performance in both models. Furthermore, both canonical and non-canonical WNT signaling pathways were activated, and most WNT proteins, especially WNT3a and WNT5a, were upregulated during the development of HEpEF in mice. CGX1321 treatment inhibited the secretion of WNT ligands and repressed both canonical and non-canonical WNT pathways, evidenced by the reduced phosphorylation of c-Jun and the nuclear translocation of ß-catenin and NFATc3. In an in vitro HFpEF model, MCM and ISO-treated cardiomyocytes, knockdown of porcupine by siRNA leads to a similar inhibitory effect on WNT pathways, cardiomyocyte hypertrophy and cardiac fibroblast activation as CGX1321 did, whereas supplementation of WNT3a and WNT5a reversed the anti-hypertrophy and anti-fibrosis effect of CGX1321. We conclude that WNT signaling activation plays an essential role in the pathogenesis of HFpEF, and porcupine inhibitor CGX1321 exerts a therapeutic effect on HFpEF in mice by attenuating cardiac hypertrophy, alleviating cardiac fibrosis and improving cardiac diastolic function.
Assuntos
Cardiomiopatias , Acetato de Desoxicorticosterona , Insuficiência Cardíaca , Animais , Camundongos , Cardiomegalia/patologia , Cardiomiopatias/patologia , Acetato de Desoxicorticosterona/farmacologia , Acetato de Desoxicorticosterona/uso terapêutico , Fibrose , Insuficiência Cardíaca/metabolismo , Miócitos Cardíacos , Volume Sistólico/fisiologia , Via de Sinalização WntRESUMO
Colorectal cancer (CRC) severely threatens human health and life span. An effective therapeutic strategy has not been established because we do not clearly know its pathogenesis. Here, we report that ceramide and sterol O-acyltransferase 1 (SOAT1) have roles in both spontaneous and chemical-induced intestinal cancers. We first found that miRNA-148a deficiency dramatically increased mouse gut dysbiosis through upregulating ceramide synthase 5 (Cers5) expression, which promoted ceramide synthesis afterward. The newly generated ceramide further promoted both azoxymethane/dextran sodium sulfate-induced (AOM/DSS-induced) and ApcMin/+ spontaneous intestinal tumorigenesis via increasing mouse gut dysbiosis. Meanwhile, increased level of ceramide correlated with the significant enhancements of both ß-catenin activity and colorectal tumorigenesis in a TLR4-dependent fashion. Next, we found a direct binding of ß-catenin to SOAT1 promoter to activate transcriptional expression of SOAT1, which further induced cholesterol esterification and colorectal tumorigenesis. In human patients with CRC, the same CERS5/TLR4/ß-catenin/SOAT1 axis was also found to be dysregulated. Finally, the SOAT1 inhibitor (avasimibe) showed significant levels of therapeutic effects on both AOM/DSS-induced and ApcMin/+ spontaneous intestinal cancer. Our study clarified that ceramide promoted CRC development through increasing gut dysbiosis, further resulting in the increase of cholesterol esterification in a SOAT1-dependent way. Treatment with avasimibe to specifically decrease cholesterol esterification could be considered as a clinical strategy for effective CRC therapy in a future study.
Assuntos
Carcinogênese/genética , Transformação Celular Neoplásica/genética , Colesterol/metabolismo , Neoplasias Colorretais/genética , Disbiose/complicações , Regulação Neoplásica da Expressão Gênica , Esterol O-Aciltransferase/genética , Animais , Ceramidas/toxicidade , Neoplasias Colorretais/etiologia , Neoplasias Colorretais/patologia , Disbiose/induzido quimicamente , Disbiose/patologia , Esterificação/genética , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Neoplasias Experimentais , RNA Neoplásico/genética , RNA Neoplásico/metabolismo , Esterol O-Aciltransferase/biossínteseRESUMO
Lipogenesis plays a critical role in colorectal carcinogenesis, but precisely how remains unclear. Here, we show that ERK2 phosphorylates ME1 at T103, thereby inhibiting its polyubiquitination and proteasomal degradation and enhancing its interaction with USP19. USP19 antagonizes RNF1-mediated ME1 degradation by deubiquitination, which in turn promotes lipid metabolism and NADPH production and suppresses ROS. Meanwhile, ROS dramatically increases PD-L1 mRNA levels through accelerating expression of the transcription factor NRF2. Increased lipid metabolism is correlated with ERK2 activity and colorectal carcinogenesis in human patients. Therefore, the combination of ERK2 inhibitor and anti-PD-L1 antibody significantly inhibits spontaneous and chemically induced colorectal carcinogenesis. Collectively, the USP19-ME1 axis plays a vital role in colorectal carcinogenesis and may also provide a potential therapeutic target.
Assuntos
Antígeno B7-H1/antagonistas & inibidores , Neoplasias Colorretais/patologia , Endopeptidases/metabolismo , Lipogênese , Proteína Quinase 1 Ativada por Mitógeno/antagonistas & inibidores , Ubiquitinação , Proteínas de Transporte Vesicular/química , Idoso , Idoso de 80 Anos ou mais , Aminopiridinas/farmacologia , Animais , Carcinogênese , Estudos de Casos e Controles , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/genética , Neoplasias Colorretais/metabolismo , Endopeptidases/genética , Feminino , Humanos , Inibidores de Checkpoint Imunológico/farmacologia , Masculino , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Fosforilação , Pirróis/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Proteínas de Transporte Vesicular/genética , Proteínas de Transporte Vesicular/metabolismoRESUMO
BACKGROUND AND AIMS: Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death that develops as a consequence of obesity, cirrhosis, and chronic hepatitis. However, the pathways along which these changes occur remain incompletely understood. APPROACH AND RESULTS: In this study, we show that the deubiquitinase USP30 is abundant in HCCs that arise in mice maintained on high-fat diets. IKKß phosphorylated and stabilized USP30, which promoted USP30 to deubiquitinate ATP citrate lyase (ACLY) and fatty acid synthase (FASN). IKKß also directly phosphorylated ACLY and facilitated the interaction between USP30 and ACLY and the latter's deubiquitination. In HCCs arising in DEN/CCl4 -treated mice, USP30 deletion attenuated lipogenesis, inflammation, and tumorigenesis regardless of diet. The combination of ACLY inhibitor and programmed death ligand 1 antibody largely suppressed chemical-induced hepatocarcinogenesis. The IKKß-USP30-ACLY axis was also found to be up-regulated in human HCCs. CONCLUSIONS: This study identifies an IKKß-USP30-ACLY axis that plays an essential and wide-spread role in tumor metabolism and may be a potential therapeutic target in HCC.
Assuntos
ATP Citrato (pro-S)-Liase/metabolismo , Carcinogênese/genética , Quinase I-kappa B/metabolismo , Lipogênese/genética , Proteínas Mitocondriais/metabolismo , Tioléster Hidrolases/metabolismo , ATP Citrato (pro-S)-Liase/antagonistas & inibidores , ATP Citrato (pro-S)-Liase/genética , Animais , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Transformação Celular Neoplásica , Dieta Hiperlipídica , Humanos , Quinase I-kappa B/genética , Metabolismo dos Lipídeos/genética , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Proteínas Mitocondriais/genética , Fosforilação , Tioléster Hidrolases/genéticaRESUMO
Metabolic alteration for adaptation of the local environment has been recognized as a hallmark of cancer. GNPAT dysregulation has been implicated in hepatocellular carcinoma (HCC). However, the precise posttranslational regulation of GNPAT is still undiscovered. Here we show that ACAT1 is upregulated in response to extra palmitic acid (PA). ACAT1 acetylates GNPAT at K128, which represses TRIM21-mediated GNPAT ubiquitination and degradation. Conversely, GNPAT deacetylation by SIRT4 antagonizes ACAT1's function. GNPAT represses TRIM21-mediated FASN degradation and promotes lipid metabolism. Furthermore, shRNA-mediated ACAT1 ablation and acetylation deficiency of GNPAT repress lipid metabolism and tumor progression in xenograft and DEN/CCl4-induced HCC. Otherwise, ACAT1 inhibitor combination with sorafenib enormously retards tumor formation in mice. Collectively, we demonstrate that stabilization of FASN by ACAT1-mediated GNPAT acetylation plays a critical role in hepatocarcinogenesis.
Assuntos
Acetil-CoA C-Acetiltransferase/metabolismo , Carcinoma Hepatocelular/metabolismo , Ácido Graxo Sintase Tipo I/metabolismo , Neoplasias Hepáticas/metabolismo , Acetilação , Animais , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Células HEK293 , Células Hep G2 , Xenoenxertos , Humanos , Metabolismo dos Lipídeos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Nus , Ácido Palmítico/farmacologia , Regulação para CimaRESUMO
Colorectal cancer (CRC) is the third most prevalent world cancer and oncogenic ß-catenin is frequently dysregulated in CRC. Long noncoding RNAs (lncRNAs) play critical roles in colorectal tumorigenesis; however, the contributions of lncRNAs to human CRC remain largely unknown. In this study, we report that LINC00265 is upregulated and predicts poor clinical outcome in human patients with CRC. Depletion of LINC00265 and ZMIZ2 distinctly attenuates colorectal tumorigenesis in mice. Mechanistically, LINC00265 augments ZMIZ2 expression by acting as an endogenous sponge against several miRNAs, which directly target ZMIZ2 expression. Moreover, ZMIZ2 recruits the enzyme USP7, which deubiquitylates and stabilizes ß-catenin, thereby facilitating colorectal tumorigenesis. In addition, ß-catenin mediates LINC00265 and ZMIZ2 oncogenic phenotypes. Taken together, the LINC00265-ZMIZ2-ß-catenin signaling axis plays a critical role in the colorectal tumorigenesis, which may be a potential therapeutic target.
Assuntos
Carcinogênese/genética , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Proteínas Inibidoras de STAT Ativados/metabolismo , RNA Longo não Codificante/metabolismo , Peptidase 7 Específica de Ubiquitina/metabolismo , beta Catenina/genética , Carcinogênese/patologia , Linhagem Celular Tumoral , Proliferação de Células/genética , Regulação Neoplásica da Expressão Gênica , Humanos , MicroRNAs/genética , MicroRNAs/metabolismo , Fenótipo , Proteínas Inibidoras de STAT Ativados/genética , Estabilidade Proteica , RNA Longo não Codificante/genética , Transdução de Sinais/genética , Transcrição Gênica , Resultado do Tratamento , Ubiquitinação , Regulação para Cima/genética , beta Catenina/metabolismoRESUMO
PGAM5 is a mitochondrial serine/threonine phosphatase that regulates multiple metabolic pathways and contributes to tumorigenesis in a poorly understood manner. We show here that PGAM5 inhibition attenuates lipid metabolism and colorectal tumorigenesis in mice. PGAM5-mediated dephosphorylation of malic enzyme 1 (ME1) at S336 allows increased ACAT1-mediated K337 acetylation, leading to ME1 dimerization and activation, both of which are reversed by NEK1 kinase-mediated S336 phosphorylation. SIRT6 deacetylase antagonizes ACAT1 function in a manner that involves mutually exclusive ME1 S336 phosphorylation and K337 acetylation. ME1 also promotes nicotinamide adenine dinucleotide phosphate (NADPH) production, lipogenesis, and colorectal cancers in which ME1 transcripts are upregulated and ME1 protein is hypophosphorylated at S336 and hyperacetylated at K337. PGAM5 and ME1 upregulation occur via direct transcriptional activation mediated by ß-catenin/TCF1. Thus, the balance between PGAM5-mediated dephosphorylation of ME1 S336 and ACAT1-mediated acetylation of K337 strongly influences NADPH generation, lipid metabolism, and the susceptibility to colorectal tumorigenesis.
Assuntos
Carcinogênese/metabolismo , Metabolismo dos Lipídeos/fisiologia , Fosforilação/fisiologia , Proteínas de Transporte Vesicular/metabolismo , Acetil-CoA C-Acetiltransferase/metabolismo , Acetilação , Animais , Carcinogênese/patologia , Linhagem Celular Tumoral , Neoplasias Colorretais/metabolismo , Neoplasias Colorretais/patologia , Feminino , Células HCT116 , Células HEK293 , Células HT29 , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , NADP/metabolismo , Fosfoproteínas Fosfatases/metabolismo , Ativação Transcricional/fisiologia , Regulação para Cima/fisiologiaRESUMO
Enrichment ratio (ER) is widely used in nonpoint source pollution models to estimate the nutrient loss associated with soil erosion. The objective of this study was to determine the ER of total nitrogen (ERN) in the sediments eroded from the typical soils with varying soil textures in Beijing mountain area. Each of the four soils was packed into a 40 by 30 by 15 cm soil pan and received 40-min simulated rainfalls at the intensity of 90 mm h(-1) on five slopes. ERN for most sediments were above unity, indicating the common occurrence of nitrogen enrichment accompanied with soil erosion in Beijing mountain area. Soil texture was not the only factor that influenced N enrichment in this experiment since the ERN for the two fine-textured soils were not always lower. Soil properties such as soil structure might exert a more important influence in some circumstances. The selective erosion of clay particles was the main reason for N enrichment, as implied by the significant positive correlation between the ER of total nitrogen and clay fraction in eroded sediments. Significant regression equations between ERN and sediment yield were obtained for two pairs of soils, which were artificially categorized by soil texture. The one for fine-textured soils had greater intercept and more negative slope. Thus, the initially higher ERN would be lower than that for the other two soils with coarser texture once the sediment yield exceeded 629 kg ha(-1).