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1.
Nat Commun ; 15(1): 4214, 2024 May 17.
Article in English | MEDLINE | ID: mdl-38760332

ABSTRACT

The liver gene expression of the peroxisomal ß-oxidation enzyme acyl-coenzyme A oxidase 1 (ACOX1), which catabolizes very long chain fatty acids (VLCFA), increases in the context of obesity, but how this pathway impacts systemic energy metabolism remains unknown. Here, we show that hepatic ACOX1-mediated ß-oxidation regulates inter-organ communication involved in metabolic homeostasis. Liver-specific knockout of Acox1 (Acox1-LKO) protects mice from diet-induced obesity, adipose tissue inflammation, and systemic insulin resistance. Serum from Acox1-LKO mice promotes browning in cultured white adipocytes. Global serum lipidomics show increased circulating levels of several species of ω-3 VLCFAs (C24-C28) with previously uncharacterized physiological role that promote browning, mitochondrial biogenesis and Glut4 translocation through activation of the lipid sensor GPR120 in adipocytes. This work identifies hepatic peroxisomal ß-oxidation as an important regulator of metabolic homeostasis and suggests that manipulation of ACOX1 or its substrates may treat obesity-associated metabolic disorders.


Subject(s)
Acyl-CoA Oxidase , Liver , Mice, Knockout , Obesity , Animals , Liver/metabolism , Mice , Acyl-CoA Oxidase/metabolism , Acyl-CoA Oxidase/genetics , Obesity/metabolism , Obesity/genetics , Male , Insulin Resistance , Mice, Inbred C57BL , Oxidation-Reduction , Lipid Metabolism , Adipose Tissue/metabolism , Diet, High-Fat , Energy Metabolism , Fatty Acids/metabolism , Receptors, G-Protein-Coupled/metabolism , Receptors, G-Protein-Coupled/genetics
3.
Mol Metab ; 82: 101913, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38458567

ABSTRACT

OBJECTIVE: Adipose tissue mass is maintained by a balance between lipolysis and lipid storage. The contribution of adipose tissue lipogenesis to fat mass, especially in the setting of high-fat feeding, is considered minor. Here we investigated the effect of adipose-specific inactivation of the peroxisomal lipid synthetic protein PexRAP on fatty acid synthase (FASN)-mediated lipogenesis and its impact on adiposity and metabolic homeostasis. METHODS: To explore the role of PexRAP in adipose tissue, we metabolically phenotyped mice with adipose-specific knockout of PexRAP. Bulk RNA sequencing was used to determine transcriptomic responses to PexRAP deletion and 14C-malonyl CoA allowed us to measure de novo lipogenic activity in adipose tissue of these mice. In vitro cell culture models were used to elucidate the mechanism of cellular responses to PexRAP deletion. RESULTS: Adipose-specific PexRAP deletion promoted diet-induced obesity and insulin resistance through activation of de novo lipogenesis. Mechanistically, PexRAP inactivation inhibited the flux of carbons to ethanolamine plasmalogens. This increased the nuclear PC/PE ratio and promoted cholesterol mislocalization, resulting in activation of liver X receptor (LXR), a nuclear receptor known to be activated by increased intracellular cholesterol. LXR activation led to increased expression of the phospholipid remodeling enzyme LPCAT3 and induced FASN-mediated lipogenesis, which promoted diet-induced obesity and insulin resistance. CONCLUSIONS: These studies reveal an unexpected role for peroxisome-derived lipids in regulating LXR-dependent lipogenesis and suggest that activation of lipogenesis, combined with dietary lipid overload, exacerbates obesity and metabolic dysregulation.


Subject(s)
Insulin Resistance , Lipogenesis , Animals , Mice , 1-Acylglycerophosphocholine O-Acyltransferase/metabolism , Adipose Tissue/metabolism , Cholesterol/metabolism , Dietary Fats/metabolism , Lipogenesis/genetics , Liver X Receptors/metabolism , Mice, Knockout , Obesity/metabolism
4.
Environ Pollut ; 347: 123742, 2024 Apr 15.
Article in English | MEDLINE | ID: mdl-38460586

ABSTRACT

Di (2-ethylhexyl) phthalate (DEHP), identified as an endocrine-disrupting chemical, is associated with reproductive toxicity. This association is particularly noteworthy in newborns with incompletely developed metabolic functions, as exposure to DEHP can induce enduring damage to the reproductive system, potentially influencing adult reproductive health. In this study, we continuously administered 40 µg/kg and 80 µg/kg DEHP to postnatal day 5 (PD5) mice for ten days to simulate low and high doses of DEHP exposure during infancy. Utilizing single-cell RNA sequencing (scRNA-seq), our analysis revealed that varying concentrations of DEHP exposure during infancy induced distinct DNA damage response characteristics in testicular Undifferentiated spermatogonia (Undiff SPG). Specifically, DNA damage triggered mitochondrial dysfunction, leading to acetyl-CoA content alterations. Subsequently, this disruption caused aberrations in histone acetylation patterns, ultimately resulting in apoptosis of Undiff SPG in the 40 µg/kg DEHP group and autophagy in the 80 µg/kg DEHP group. Furthermore, we found that DEHP exposure impacts the development and functionality of Sertoli and Leydig cells through the focal adhesion and PPAR signaling pathways, respectively. We also revealed that Leydig cells regulate the metabolic environment of Undiff SPG via Ptn-Sdc4 and Mdk-Sdc4 after DEHP exposure. Finally, our study provided pioneering evidence that disruptions in testicular homeostasis induced by DEHP exposure during infancy endure into adulthood. In summary, this study elucidates the molecular mechanisms through which DEHP exposure during infancy influences the development of testicular cell populations.


Subject(s)
Diethylhexyl Phthalate , Phthalic Acids , Spermatogonia , Male , Mice , Animals , Diethylhexyl Phthalate/metabolism , Histones/metabolism , Acetylation , Testis/metabolism , Homeostasis
5.
JCI Insight ; 9(6)2024 02 22.
Article in English | MEDLINE | ID: mdl-38516886

ABSTRACT

Kidney tubules use fatty acid oxidation (FAO) to support their high energetic requirements. Carnitine palmitoyltransferase 1A (CPT1A) is the rate-limiting enzyme for FAO, and it is necessary to transport long-chain fatty acids into mitochondria. To define the role of tubular CPT1A in aging and injury, we generated mice with tubule-specific deletion of Cpt1a (Cpt1aCKO mice), and the mice were either aged for 2 years or injured by aristolochic acid or unilateral ureteral obstruction. Surprisingly, Cpt1aCKO mice had no significant differences in kidney function or fibrosis compared with wild-type mice after aging or chronic injury. Primary tubule cells from aged Cpt1aCKO mice had a modest decrease in palmitate oxidation but retained the ability to metabolize long-chain fatty acids. Very-long-chain fatty acids, exclusively oxidized by peroxisomes, were reduced in kidneys lacking tubular CPT1A, consistent with increased peroxisomal activity. Single-nuclear RNA-Seq showed significantly increased expression of peroxisomal FAO enzymes in proximal tubules of mice lacking tubular CPT1A. These data suggest that peroxisomal FAO may compensate in the absence of CPT1A, and future genetic studies are needed to confirm the role of peroxisomal ß-oxidation when mitochondrial FAO is impaired.


Subject(s)
Carnitine O-Palmitoyltransferase , Kidney , Animals , Mice , Aging/genetics , Carnitine O-Palmitoyltransferase/genetics , Carnitine O-Palmitoyltransferase/metabolism , Fatty Acids/metabolism , Kidney/metabolism , Kidney/pathology , Kidney Tubules/metabolism
6.
Sci Total Environ ; 916: 170092, 2024 Mar 15.
Article in English | MEDLINE | ID: mdl-38246374

ABSTRACT

The spatial-temporal distributions of various nitrogen (N) species in surface sediments were examined in a typical subtropical mariculture bay (Maowei Sea) in the northern Beibu Gulf to assess the impact of intensive oyster culture activities on sedimentary N speciation. The results indicated that the mean contents of total nitrogen (TN), extractable (labile) nitrogen (LN) and residual nitrogen (RN) in the surface sediments were 33.3 ± 15.5 µmol g-1, 13.8 ± 1.3 µmol g-1 and 19.5 ± 15.0 µmol g-1, respectively, which lacked significant seasonal variability (P > 0.05). Four forms of LN, namely ion extractable form (IEF-N), weak acid extractable form (WAEF-N), strong alkali extractable form (SAEF-N) and strong oxidant extractable form (SOEF-N) were identified based on sequential extraction. SOEF-N was the dominant form of LN, accounting for 67.8 ± 2.5 % and 63.7 ± 5.9 % in summer and winter, respectively. Spatially, the contents of sedimentary TN, LN, RN, WAEF-N and SOEF-N in intensive mariculture areas (IMA) were significantly higher than those in non-intensive mariculture areas (NIMA) during summer (P < 0.05). Stable nitrogen isotope (δ15N) mixing model revealed that shellfish biodeposition was the predominant source of sedimentary TN in IMA with a contribution of 67.8 ± 23.0 %, approximately 5.4 times that of NIMA (12.6 ± 3.3 %). Significant positive correlations (P < 0.05) were observed between most forms of N species (WAEF-N, SOEF-N, LN and RN) and shellfish-biodeposited N in the surface sediments during summer, indicating that intensive oyster farming greatly enhanced sedimentary TN accumulation.


Subject(s)
Ostreidae , Water Pollutants, Chemical , Animals , Nitrogen/analysis , Geologic Sediments , Bays , Water Pollutants, Chemical/analysis , Environmental Monitoring , Agriculture , China
7.
Chemosphere ; 346: 140603, 2024 Jan.
Article in English | MEDLINE | ID: mdl-37918532

ABSTRACT

Tire wear particles (TWPs) are a major source of environmental microplastic pollution which gradually settle and accumulate in sediments after entering the aquatic environment, which can affect the behaviors of benthic organisms. Bioturbation of benthic species could affect the fate, impacts and potential risks of TWPs by altering the properties and structure of sediments. Therefore, in this study, the effect of TWPs on the burrowing activity of Chinese mitten crab (Eriocheir sinensis) was investigated. In addition, the effects of crab bioturbation on the distribution of TWPs and their additives were studied. The combined effects of TWPs and crab bioturbation on the microbial communities in the sediments were also explored. The results of this study showed that both TWPs and the leachate significantly inhibited the burrowing activity of crabs. TWPs in the surface layer of sediments were re-distributed by crab bioturbation and enriched mainly in the sediments near the burrow walls. Meanwhile, the heavy metals (i.e., Zn, Ca, Mg, Ba and Al) used as additives during the tire production in the burrow walls significantly increased as the accumulation of TWPs near burrow walls. In this study, TWP exposure decreased the bacterial diversity and abundance, as well as the functional genes related to carbon and nitrogen cycling process, but crab bioturbation increased them in the sediments of burrow walls by constructing a unique habitat. However, after TWPs entering into burrows, they were significantly decreased in the sediments near the burrow walls like the effects of TWPs, suggesting the negative effects of TWPs could play a dominant role in this combined system. Overall, this study is important for evaluating the distribution and effects of TWP pollution in the sediment ecosystem under biological factors such as bioturbation.


Subject(s)
Ecosystem , Microbiota , Geologic Sediments/chemistry , Plastics , Bacteria/genetics , Carbon
8.
Environ Sci Pollut Res Int ; 30(56): 119406-119418, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37925373

ABSTRACT

This study examined the nexus between per capita gross ocean product (GOP) growth and total nitrogen (TN), total phosphorus (TP), and chemical oxygen demand (COD) discharged from land-based sources in Guangxi and China. Multiple pollution indicators, such as red tide area (RTA), seawater quality area (SWQA), and eutrophication area (EA), were used as marine environmental quality indicators, and annual time series data during the period 2010-2019 were employed. The data were analyzed using the environment Kuznets curve fitting model. Results showed that the average annual growth rates of the GOP and gross domestic product (GDP) of China were 9.88% and 10.79%, respectively, and those of Guangxi were 13.62% and 10.02%, respectively. The average annual GOP ratio in GDP for Guangxi and China was 6.59 and 9.47, respectively. The marine tertiary industry was the most dominant marine industry; it accounted for 41.12-50.01% (mean: 46.12%) of Guangxi's GDP and 47-60% (mean: 52.47%) of China's GDP. The TP, COD, SWQA, and EA of Guangxi and the TP, TN, COD, SWQA, and EA of China displayed inverted U-shaped GOP growth. These findings indicate that the marine economic growth and marine environmental quality of Guangxi and China are harmonious. However, TN increased synchronously with marine economic growth in Guangxi. Therefore, the industrial structure must be further optimized, pollutant discharge management must be strengthened, and the harmonious development of Guangxi's marine economy and marine environment needs to be promoted.


Subject(s)
Economic Development , Environmental Pollutants , China , Environmental Pollution/analysis , Biological Oxygen Demand Analysis , Gross Domestic Product
9.
Nat Commun ; 14(1): 6099, 2023 09 29.
Article in English | MEDLINE | ID: mdl-37773161

ABSTRACT

Mitochondrial morphology, which is controlled by mitochondrial fission and fusion, is an important regulator of the thermogenic capacity of brown adipocytes. Adipose-specific peroxisome deficiency impairs thermogenesis by inhibiting cold-induced mitochondrial fission due to decreased mitochondrial membrane content of the peroxisome-derived lipids called plasmalogens. Here, we identify TMEM135 as a critical mediator of the peroxisomal regulation of mitochondrial fission and thermogenesis. Adipose-specific TMEM135 knockout in mice blocks mitochondrial fission, impairs thermogenesis, and increases diet-induced obesity and insulin resistance. Conversely, TMEM135 overexpression promotes mitochondrial division, counteracts obesity and insulin resistance, and rescues thermogenesis in peroxisome-deficient mice. Mechanistically, thermogenic stimuli promote association between peroxisomes and mitochondria and plasmalogen-dependent localization of TMEM135 in mitochondria, where it mediates PKA-dependent phosphorylation and mitochondrial retention of the fission factor Drp1. Together, these results reveal a previously unrecognized inter-organelle communication regulating mitochondrial fission and energy homeostasis and identify TMEM135 as a potential target for therapeutic activation of BAT.


Subject(s)
Adipose Tissue, Brown , Insulin Resistance , Animals , Mice , Adipocytes, Brown , Adipose Tissue, Brown/physiology , Homeostasis , Mice, Knockout , Mitochondrial Dynamics , Obesity , Peroxisomes , Thermogenesis
10.
Front Endocrinol (Lausanne) ; 14: 1222635, 2023.
Article in English | MEDLINE | ID: mdl-37484950

ABSTRACT

Introduction: In recent years, the quality of male semen has been decreasing, and the number of male infertilities caused by asthenozoospermia is increasing year by year, and the diagnosis and treatment of patients with asthenozoospermia are gradually receiving the attention of the whole society. Due to the unknown etiology and complex pathogenesis, there is no specific treatment for asthenozoospermia. Our previous study found that the administration of chestnut polysaccharide could alter the intestinal microbiota and thus improve the testicular microenvironment, and rescue the impaired spermatogenesis process by enhancing the expression of reproduction-related genes, but its exact metabolome-related repairment mechanism of chestnut polysaccharide is still unclear. Methods and results: In this study, we studied the blood metabolomic changes of busulfan-induced asthenozoospermia-model mice before and after oral administration of chestnut polysaccharide with the help of metabolome, and screened two key differential metabolites (hydrogen carbonate and palmitic acid) from the set of metabolomic changes; we then analyzed the correlation between several metabolites and between different metabolites and intestinal flora by correlation analysis, and found that palmitic acid in the blood serum of mice after oral administration of chestnut polysaccharide had different degrees of correlation with various metabolites, and palmitic acid level had a significant positive correlation with the abundance of Verrucomicrobia; finally, we verified the role of palmitic acid in rescuing the damaged spermatogenesis process by using asthenozoospermia-model mice, and screened the key target gene for palmitic acid to play the rescuing effect by integrating the analysis of multiple databases. Discussion: In conclusion, this study found that chestnut polysaccharide rescued the damaged spermatogenesis in asthenozoospermia-model mice by upregulating palmitic acid level, which will provide theoretical basis and technical support for the use of chestnut polysaccharide in the treatment of asthenozoospermia.


Subject(s)
Asthenozoospermia , Infertility, Male , Humans , Male , Animals , Mice , Asthenozoospermia/chemically induced , Asthenozoospermia/drug therapy , Asthenozoospermia/genetics , Palmitic Acid , Spermatogenesis/genetics , Testis/metabolism , Infertility, Male/genetics , Polysaccharides/pharmacology
11.
Mar Environ Res ; 189: 106076, 2023 Jul.
Article in English | MEDLINE | ID: mdl-37399675

ABSTRACT

The toxicity of heavy metals is dependent on their bioavailability. This study explored the relationship existing among sedimentary nutrients such as bulk nitrogen (TN) and phosphorus (TP), organic carbon (OC), water column chlorophyll-a (Chl-a) and the poorly-bound fraction of sedimentary heavy metals (Cd, Ni, Zn, Cu, Pb and Cr) in the Dafengjiang River Estuary and adjacent Sanniang bay in 2017 and 2018. Results showed that the texture of the surface sediments was dominated by coarse sand, while sedimentary organic matter was dominated by marine phytoplankton and mariculture biodeposits. Surprisingly, concentrations of poorly-bound heavy metals in sediments were relatively high. The average contents of Cd and Ni did not vary both spatially and temporally, Cu and Pb only varied spatially, Cr varied both spatially and temporally, while Zn only varied temporally. Significant positive correlations occurred between sedimentary TN, TP, and OC, including water column Chl-a and poorly-bound heavy metals in sediments. As sediments are important sources of nutrients for primary productivity, the results of this study suggest that the remobilization of sequestered poorly-bound heavy metals in surface sediments deposited in shallow eutrophic estuaries and coastal waters enriched by labile organic matter can enhance by nutrients. The relationship between the poorly-bound heavy metals and nutrients in surface sediments and water column Chl-a is concerning and requires further in-depth investigation. This is because estuaries are economically important ecosystems rich in bioresources, characterized by dynamic biogeochemical conditions.


Subject(s)
Metals, Heavy , Water Pollutants, Chemical , Estuaries , Cadmium , Bays , Ecosystem , Lead , Geologic Sediments/chemistry , Environmental Monitoring/methods , Metals, Heavy/analysis , Rivers/chemistry , Water , Water Pollutants, Chemical/analysis , China , Risk Assessment
12.
Methods Mol Biol ; 2662: 219-239, 2023.
Article in English | MEDLINE | ID: mdl-37076685

ABSTRACT

Brown adipose tissue (BAT) is an important regulator of metabolic homeostasis through its role in adaptive thermogenesis and control of whole-body glucose metabolism. Lipids play multiple roles in BAT functions, including serving as a fuel source for thermogenesis, mediating inter-organelle cross talk, and acting as BAT-derived signaling molecules that influence systemic energy metabolism. Profiling of various lipids in BAT under distinct metabolic states could provide new insights into their roles in the biology of the thermogenic fat. In this chapter, we describe a step-by-step workflow starting from sample preparations to mass spectrometry-based analysis of fatty acids and phospholipids in BAT.


Subject(s)
Adipose Tissue, Brown , Energy Metabolism , Adipose Tissue, Brown/metabolism , Thermogenesis , Homeostasis , Fatty Acids/metabolism
13.
Mar Environ Res ; 184: 105855, 2023 Feb.
Article in English | MEDLINE | ID: mdl-36610306

ABSTRACT

Harmful algal blooms caused by Heterocapsa bohaiensis have broken out in aquaculture areas near Liaodong Bay, China, since 2012, resulting in mass mortality of Eriocheir sinensis larvae and substantial economic loss. Chlorella pyrenoidosa is a local phytoplankton species that is found in aquaculture ponds. However, the reason why H. bohaiensis dominated and proliferated in the phytoplankton community remains unknown. Previous studies have revealed the toxicity and hemolytic activity of H. bohaiensis. It is suspected that the out-competition of H. bohaiensis to C. pyrenoidosa was associated with toxicity. Filtrate and bi-algal cultures were investigated to determine the interspecific competition between H. bohaiensis and C. pyrenoidosa in this study. Filtrate experiments revealed that H. bohaiensis showed no toxin allelopathy in C. pyrenoidosa. However, the C. pyrenoidosa filtrates had significant allelopathic effects on the growth of H. bohaiensis. The bi-algal culture experiments and the simulation showed that the dominant species were dependent on the initial cell density ratios of the species and nutrient ratios. Therefore, H. bohaiensis achieved competitive advantage through exploitation competition but not allelopathy. The results contribute to the reasons for the occurrence of H. bohaiensis blooms in a further study.


Subject(s)
Chlorella , Dinoflagellida , Harmful Algal Bloom , Phytoplankton , Ecology
14.
J Transl Med ; 21(1): 40, 2023 01 21.
Article in English | MEDLINE | ID: mdl-36681849

ABSTRACT

BACKGROUND: Current diagnosis tools for prostate cancer (PCa) such as serum PSA detection and prostate biopsy cannot distinguish dormant tumors from invasive malignancies, either be used as prognosis marker for castration resistant prostate cancer (CRPC), the lethal stage of PCa patients. Exosomes have been widely investigated as promising biomarkers for various diseases. We aim to characterize the proteomic and metabolomic profile of exosomes and to evaluate their potential value for the diagnosis of PCa, especially CRPC. We also investigate the functions of some specific exosome biomarkers in the progression of CRPC. METHODS: Integrated proteomics and metabolomics analysis were performed for plasma-derived exosomes collected from tumor-free controls (TFC), PCa and CRPC patients. Expression of specific exosomal proteins were further validated by targeted 4D-parallel reaction monitoring (PRM) mass spectrometry among the three cohorts. Tissue distribution and functional role of exosomal protein LRG1 was studied in clinical PCa tissue samples and cell line models. RESULTS: Three potential exosomal protein markers were identified. The apolipoprotein E level in PCa samples was 1.7-fold higher than that in TFC (receiver operating characteristic value, 0.74). Similarly, the levels of exosome-derived leucine-rich alpha2-glycoprotein 1 (LRG1) and inter-alpha-trypsin inhibitor heavy chain H3 (ITIH3) in the CRPC group were 1.7 and 2.04 times, respectively, higher than those in the PCa group (ROC values, 0.84 and 0.85, respectively), indicating that LRG1 and ITIH3 could serve as predictive markers for CRPC. For metabolomic evaluation of exosomes, a series of differentially expressed metabolites were identified, and a combined metabolite panel showed ROC value of 0.94 for distinguishing PCa from TFC and 0.97 for distinguishing CRPC from PCa. Immunohistochemistry of tissue microarray showed that LRG1 protein was significantly upregulated in advanced prostate cancer and functional assay revealed that ectopic expression of LRG1 can significantly enhance the malignant phenotype of prostate cancer cells. More importantly, PCa cell derived LRG1-overexpressed exosomes remarkably promoted angiogenesis. CONCLUSION: Integration of proteomics and metabolomics data generated proteomic and metabolic signatures of plasma exosomes that may facilitate discrimination of CRPC from PCa and TFC patients, suggesting the potential of exosomal proteins and metabolites as CRPC markers. The study also confirmed the important role of exosomal protein LRG1 in PCa malignant progression.


Subject(s)
Exosomes , Prostatic Neoplasms, Castration-Resistant , Humans , Male , Prostatic Neoplasms, Castration-Resistant/genetics , Prostatic Neoplasms, Castration-Resistant/metabolism , Prostatic Neoplasms, Castration-Resistant/pathology , Proteomics , Prostate/metabolism , Exosomes/metabolism
15.
Mar Pollut Bull ; 185(Pt A): 114257, 2022 Dec.
Article in English | MEDLINE | ID: mdl-36274556

ABSTRACT

The speciation of heavy metals (Ni, Cr, Cu, Zn, Pb, and Cd) was studied in surface sediments of the Cross River Estuary (CRE), Gulf of Guinea, South East Nigeria. Pb (~56 %), Cd (~71 %), Zn (~67 %), and Cr (~76 %) were mainly available in non-residual phases, suggesting potential bioavailability. High contents of Ni and Cu in residual phase indicated immobilization of these metals in aluminosilicate minerals. Cd was the most polluted heavy metal with the highest bioavailability risk. Bayesian Network model results revealed that sedimentary organic carbon (OC) from terrestrial C3 plants controlled the contents and variability of Pb and Zn, while the input of terrestrial soil OC strongly influenced Cu and Ni. However, Cd and Cr were dominantly influenced by sediment pH, while Ni was mainly influenced by sediment salinity. Strong interdependency between Cd and total nitrogen (TN) suggested that nitrogen might increase Cd bioavailability upon release from sediments.


Subject(s)
Metals, Heavy , Water Pollutants, Chemical , Estuaries , Geologic Sediments/chemistry , Guinea , Bayes Theorem , Cadmium , Lead , Nigeria , Environmental Monitoring/methods , Water Pollutants, Chemical/analysis , Metals, Heavy/analysis , Nitrogen , China , Risk Assessment
16.
Mar Pollut Bull ; 179: 113708, 2022 Jun.
Article in English | MEDLINE | ID: mdl-35533618

ABSTRACT

The contents of chemothermal oxidation (CTO)-derived black carbon (BC) and organic carbon (OC) and their stable isotopes (δ13CBC and δ13COC), including major elemental oxides, and grain sizes were measured to constrain the sources, burial flux, and mass inventory of BC in surface sediments of the Daya Bay. Surface sediments were mainly clayey silt (>90%) and contained 0.28-1.18% OC and 0.05-0.18% BC. Fossil fuel emission and physical erosion contributed to the sedimentary BC sources. High BC/OC ratio (6-30%), burial flux (154.88-922.67 µg cm-2 y-1), and mass inventory (22-34 Gg y-1) of BC in the upper 5 cm of surface sediments indicated that the Daya Bay is a significant sink of BC. The high accumulation of BC in sediments is attributed to a strong affinity to fine-grained sediments due to the enrichment of muddy biodeposits excrements from the cultured species in the bay.


Subject(s)
Bays , Geologic Sediments , Burial , Carbon/analysis , China , Environmental Monitoring , Soot/analysis
17.
J Chromatogr A ; 1665: 462826, 2022 Feb 22.
Article in English | MEDLINE | ID: mdl-35066295

ABSTRACT

The present work aimed at the development of a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for comprehensive determination of twelve organophosphate (OP) triesters, five OP diesters and two hydroxylated degradation products in sediment. As the target compound possess a wide range of physicochemical properties, different LC-MS/MS conditions and sample preparation strategies were tested. The optimal condition is based on the extraction of 2 g of dried sediment by ultrasonic-assisted extraction and clean-up by solid phase extraction, and then the extract was separated using a ZORBAX C18 column (4.6 mm × 100 mm, 1.8 µm) and analyzed by MS in multiple reaction monitoring mode. The overall method was validated in terms of linearity, matrix effect, and limits of quantification (LOQs), recoveries and precision. All targets had wide concentration ranges and the correlation coefficients (r) were higher than 0.99. LOQs of all analytes were 0.01-5.0 ng g-1 dw, most of which are lower than those previously reported. In most cases, the recoveries were from 68.56 to 140.22% at three spiked levels (low, medium and high), with RSDs lower than 22.38%, and the reproducibility obtained in five nonconsecutive days was lower than 26.18%. This method was successfully applied to nineteen marine sediment samples. Tri-n-butyl phosphate (TNBP) and tris (phenyl) phosphate (TPHP) were detected in over 84% of samples and the concentration levels were the highest among all OP triesters. For OP diesters, DPHP was 100% detected in all samples with the highest amount. The total concentrations for OP triesters and their degradation products were n.d.-107.2 ng g-1 dw and n.d.-101.7 ng g-1 dw, respectively. This is the first study reporting contamination of both OP triesters and their degradation products, especially hydroxylated degradation products, in sediment. Considering the ubiquitous existence of targets as well as their toxicity to biota, study on the OPEs and their degradation products in marine environment deserves a special attention.


Subject(s)
Organophosphates , Tandem Mass Spectrometry , Chromatography, High Pressure Liquid , Chromatography, Liquid , Esters , Reproducibility of Results , Solid Phase Extraction
18.
Molecules ; 26(11)2021 Jun 04.
Article in English | MEDLINE | ID: mdl-34199966

ABSTRACT

Nanfeng mandarins (Citrus reticulata Blanco cv. Kinokuni), Xunwu mandarins (Citrus reticulata Blanco), Yangshuo kumquats (Citrus japonica Thunb) and physiologically dropped navel oranges (Citrus sinensis Osbeck cv. Newhall) were used as materials to extract peel essential oils (EOs) via hydrodistillation. The chemical composition, and antibacterial and antioxidant activities of the EOs were investigated. GC-MS analysis showed that monoterpene hydrocarbons were the major components and limonene was the predominate compound for all citrus EOs. The antibacterial testing of EOs against five different bacteria (Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Salmonella typhimurium) was carried out using the filter paper method and the broth microdilution method. Kumquat EO had the best inhibitory effect on B. subtilis, E. coli and S. typhimurium with MIC (minimum inhibitory concentration) values of 1.56, 1.56 and 6.25 µL/mL, respectively. All citrus EOs showed the antioxidant activity of scavenging DPPH and ABTS free radicals in a dose-dependent manner. Nanfeng mandarin EO presented the best antioxidant activity, with IC50 values of 15.20 mg/mL for the DPPH assay and 0.80 mg/mL for the ABTS assay. The results also showed that the antibacterial activities of EOs might not be related to their antioxidant activities.


Subject(s)
Anti-Bacterial Agents/chemistry , Antioxidants/chemistry , Citrus/chemistry , Oils, Volatile/pharmacology , Anti-Bacterial Agents/isolation & purification , Anti-Bacterial Agents/pharmacology , Antioxidants/isolation & purification , Antioxidants/pharmacology , Bacillus subtilis/drug effects , Citrus/classification , Distillation , Dose-Response Relationship, Drug , Escherichia coli/drug effects , Gas Chromatography-Mass Spectrometry , Microbial Sensitivity Tests , Oils, Volatile/chemistry , Oils, Volatile/isolation & purification , Plant Oils/chemistry , Plant Oils/isolation & purification , Plant Oils/pharmacology , Pseudomonas aeruginosa/drug effects , Salmonella typhimurium/drug effects , Staphylococcus aureus/drug effects
19.
Chem Biol Interact ; 348: 109569, 2021 Oct 01.
Article in English | MEDLINE | ID: mdl-34197824

ABSTRACT

As one of the most important members of Phthalate esters (PAEs), di-(2-ethylhexyl) phthalate (DEHP) is widely used in plastics and known as a male reproductive toxicant. Many studies have shown that soybean isoflavones (SI) can rescue the testicular injury caused by DEHP, but the underlying mechanism is unknown. Because methylation is one of the most important mechanisms for maintaining normal biological functions, we studied whether methylation is involved in testicular injury induced by DEHP and whether SI could counter testicular impairment in peripubertal male Sprague Dawley rats. Compared with the control group, we found that the mRNA levels of testicular Sod2, Gpx1, and Igf-1 significantly decreased in the 900 mg/kg DEHP group (DEHP' group) (P < 0.01); however, in the DEHP + SI group, the mRNA levels of the genes obviously increased compared with the DEHP' group (P < 0.01). Simultaneously, the methylation level changes of testicular Sod2, Gpx1, and Igf-1 were similar to the mRNA levels (P < 0.01). Therefore, DEHP may affect testis and leydig cells via inducing methylation of Sod2, Gpx1, and Igf-1, and SI may rescue the impairments at the methylation level. In summary, SI is supposed to be used in DEHP-induced testicular injury treatment.


Subject(s)
DNA Methylation/drug effects , Diethylhexyl Phthalate/toxicity , Glycine max/chemistry , Isoflavones/pharmacology , Testis/drug effects , Testis/injuries , Animals , Cytoprotection/drug effects , Glutathione Peroxidase/metabolism , Leydig Cells/drug effects , Male , Oxidative Stress/drug effects , Rats , Rats, Sprague-Dawley , Reproduction/drug effects , Testis/cytology , Testis/metabolism , Glutathione Peroxidase GPX1
20.
Mar Pollut Bull ; 168: 112368, 2021 Jul.
Article in English | MEDLINE | ID: mdl-33901908

ABSTRACT

The occurrence, distributions, and ecological risks of 11 organophosphate flame retardants (OPFRs) were investigated in the seawater and sediment samples from the Qinzhou Bay. The Σ11OPFRs in the surface seawater and sediments ranged from 150 to 885 ng/L and from

Subject(s)
Flame Retardants , Bays , Flame Retardants/analysis , Organophosphates/analysis , Organophosphorus Compounds/analysis , Risk Assessment , Seawater
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