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1.
Biotechnol Lett ; 2024 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-39031272

RESUMO

OBJECTIVES: Developing a simplified flask fermentation strategy utilizing magnetotactic bacterium AMB-1 and optimized iron supplementation for high-yield magnetosome production to address the challenges associated with magnetosome acquisition. RESULTS: A reliable processing for the pure culture of AMB-1 was established using standard laboratory consumables and equipment. Subsequently, the medium and iron supplementation were optimized to enhance the yield of AMB-1 magnetosomes. The mSLM supported higher biomass accumulation in flask fermentation, reaching an OD565 of ~ 0.7. The premixed solution of ferric quinate and EDTA-Fe (at a ratio of 0.5:0.5 and a concentration of 0.4 mmol/L) stabilized Fe3+ and significantly increased the reductase activity of AMB-1. Flask fermentations with an initial volume of 15 L were then conducted employing the optimized fermentation strategy. After two rounds of iron and nutrient supplementation, the magnetosome yield reached 185.7 ± 9.5 mg/batch (approximately 12 mg/L), representing the highest AMB-1 flask fermentation yield to our knowledge. CONCLUSION: A flask fermentation strategy for high-yield magnetsome production was developed, eliminating the need for bioreactors and greatly simplifying the process of magnetosome acquisition.

2.
Artigo em Inglês | MEDLINE | ID: mdl-38642118

RESUMO

Childhood maltreatment has long-term negative effects on individuals' physical and mental well-being, and may increase the risk for suicidal ideation. However, how different patterns of childhood maltreatment affect subsequent suicidal ideation and the underlying mediating mechanisms remain unclear, particularly among Chinese adolescents. This study used latent profile analysis to identify patterns of childhood maltreatment among adolescents and explored how these patterns predicted subsequent suicidal ideation via depression, hope, and expressive suppression. This study used a two-wave, 1-year longitudinal design and included 2156 adolescents (Mage = 13.97 years, SDage = 1.61 years; 49.6% females). We identified three patterns of childhood maltreatment: low maltreatment, high psychological neglect, and high maltreatment. Compared with the low maltreatment group, the high maltreatment group indirectly predicted subsequent suicidal ideation 1 year later via depression through hope and expressive suppression, whereas the direct effect on suicidal ideation was not significant. Compared with the low maltreatment group, the high psychological neglect group had a significant direct effect on subsequent suicidal ideation and indirectly predicted suicidal ideation through depression or hope. Identifying patterns of childhood maltreatment among adolescents will assist mental health workers in developing targeted interventions to effectively alleviate suicidal ideation.

3.
Molecules ; 29(9)2024 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-38731552

RESUMO

Herein, we have developed a new approach for the synthesis of indolizine via Cu-catalyzed reaction of pyridine, acetophenone, and nitroolefin under mild conditions in high yields. This reaction involved the formation of C-N and C-C bonds and new indolizine compounds with high stereoselectivity and excellent functional group tolerance.

4.
J Ment Health ; : 1-9, 2024 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-38602358

RESUMO

BACKGROUND: Posttraumatic stress disorder (PTSD) symptoms after natural disaster can have a detrimental effect on marital relationships, which may be through parenting-related factor. AIMS: The study aimed to examine the mechanism underlying the long-term effects of PTSD symptoms on marital satisfaction via coparenting, and its differences between men and women following the Super Typhoon Lekima. METHODS: Participants were 465 married victims with children. They reported their PTSD, coparenting, and marital satisfaction at three and fifteen months after the tropical cyclone. RESULTS: The results showed that for women, only higher negative cognitive and emotional alterations (NCEA) symptoms were associated with lower marital satisfaction through conflict coparenting. For men, higher intrusion, NCEA, and hyperarousal symptoms were associated with marital satisfaction through different coparenting. To be specific, for men, higher intrusion symptoms were associated with lower marital satisfaction via less reprimand coparenting; higher NCEA symptoms were associated with lower marital satisfaction via less integrity coparenting, and associated with higher marital satisfaction via less conflict coparenting; higher hyperarousal symptoms were associated with lower marital satisfaction via more conflict coparenting. CONCLUSIONS: These findings suggested that the long-term effect of PTSD symptoms on marital satisfaction via coparenting mainly showed for men.

5.
Angew Chem Int Ed Engl ; : e202410297, 2024 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-39031447

RESUMO

Metal-free synthesis of heterocycles is highly sought after in the pharmaceutical industry and has garnered widespread attention due to its environmental sustainability and cost-effectiveness. We report a radical 6-endo addition method for pyridine synthesis from cyclopropylamides and alkynes under metal-free conditions. Various terminal and substituted alkynes are inserted as C2 units into cyclopropylamides to synthesize versatile pyridines with more than 51 examples. Mechanistic investigations and computational studies indicate the unprecedented 6-endo-trig addition of vinyl radicals to the imine nitrogen atom rather than the conventional 5-exo-trig addition to the imine carbon atom, in which the hypervalent iodine(III) plays a critical role. This reaction easily scales up with excellent functional group compatibility and suits the late-stage pyridine installation on complex molecules.

6.
Microb Cell Fact ; 22(1): 6, 2023 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-36611199

RESUMO

Phaeodactylum tricornutum (Pt) is a critical microbial cell factory to produce a wide spectrum of marketable products including recombinant biopharmaceutical N-glycoproteins. N-glycosylation modification of proteins is important for their activity, stability, and half-life, especially some special modifications, such as fucose-modification by fucosyltransferase (FucT). Three PtFucTs were annotated in the genome of P. tricornutum, PtFucT1 was located on the medial/trans-Golgi apparatus and PtFucT2-3 in the plastid stroma. Algal growth, biomass and photosynthesis efficiency were significantly inhibited in a knockout mutant of PtFucT1 (PtFucT1-KO). PtFucT1 played a role in non-core fucose modification of N-glycans. The knockout of PtFucT1 might affect the activity of PtGnTI in the complex and change the complex N-glycan to mannose type N-glycan. The study provided critical information for understanding the mechanism of protein N-glycosylation modification and using microalgae as an alternative ecofriendly cell factory to produce biopharmaceuticals.


Assuntos
Diatomáceas , Fucosiltransferases , Fucosiltransferases/genética , Fucosiltransferases/metabolismo , Diatomáceas/genética , Diatomáceas/metabolismo , Fucose/metabolismo , Sistemas CRISPR-Cas , Proteínas Recombinantes/metabolismo , Polissacarídeos/metabolismo , Complexo de Golgi/genética , Complexo de Golgi/metabolismo , Galactosídeo 2-alfa-L-Fucosiltransferase
7.
Appl Opt ; 62(14): 3535-3541, 2023 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-37706966

RESUMO

We report on a laser-diode (LD)-pumped master-oscillator power amplifier (MOPA) mid-infrared laser system based on an LD side-pumped Er:YSGG seed laser that can operate in both free-running and Q-switched regimes. In the free-running mode of the seed laser, the maximum amplified single-pulse energy was 83.4 mJ. In Q-switched mode of the seed laser, a maximum single-pulse energy of 7.8 mJ was achieved at 100 Hz repetition rate with the pulse width of 90 ns, corresponding to the peak power of 86.7 kW and the single-pass amplification factor of 1.66. The results indicate that the LD side-pumped MOPA structure is an effective way to realize a nanosecond ∼3µm mid-infrared laser with high repetition rate and high pulse energy.

8.
J Adolesc ; 95(8): 1590-1602, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37530099

RESUMO

INTRODUCTION: Several studies have examined the impact of parents' posttraumatic stress disorder (PTSD) on their children's mental health, but few have evaluated the role of parents' specific PTSD trajectories. The aim of this study was to assess the mechanisms underlying distinct trajectories of parental PTSD that affect children's PTSD and depression through the feeling of safety. METHODS: The final sample comprised 242 dyads of parents and their children who experienced Super Typhoon Lekima in 2019. All participants were surveyed at three time points after the typhoon: 3 months (T1), 15 months (T2), and 27 months (T3). Parental PTSD symptoms at three time points and children's PTSD, depression, and feeling of safety at T3 were analyzed. RESULTS: Four parental PTSD trajectories were identified: recovery, resilience, delayed, and coping. Compared with the resilient group, children of parents with delayed PTSD trajectories reported higher levels of depression at T3, while children of parents in the coping group were more likely to experience severe PTSD at T3. Children of parents in the recovery group, with a reduced feeling of safety, exhibited more severe depression and PTSD at T3, whereas children of parents in the delayed group were at an increased risk of PTSD at T3. CONCLUSIONS: These findings highlight the heterogeneity of parental PTSD trajectories following natural disasters and their distinct effects on children's PTSD and depression. Furthermore, feeling of safety emerges as a crucial mechanism in this process.


Assuntos
Tempestades Ciclônicas , Transtornos de Estresse Pós-Traumáticos , Humanos , Criança , Transtornos de Estresse Pós-Traumáticos/psicologia , Saúde Mental , Pais/psicologia , Emoções
9.
J Youth Adolesc ; 52(11): 2314-2327, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37468821

RESUMO

Many studies have examined post-traumatic stress disorder (PTSD) or depressive symptoms in adolescents under the background of school bullying, but not their comorbidities and changes over time. This study used random intercept latent transition analysis (RI-LTA) to examine the transitions in comorbid patterns of PTSD and depressive symptoms among 815 adolescents (45.0% boys; Mage-baseline = 13.69, SD = 1.60), who reported their symptoms in a 3-year longitudinal study. Three comorbid patterns were found: low symptoms, predominantly PTSD symptoms, and symptoms of comorbidity. Among these patterns, five trends were found through 3 years: stable low symptoms, stable PTSD symptoms, improving symptoms, worsening symptoms, and an inverted-U pattern. Age, time that parents spend with their child, being an only child, family income and experiencing relational bullying were predictors of these transitions. These suggest that patterns of PTSD and depressive symptoms are heterogeneous and may change over time since trauma events. Developing targeted interventions based on underlying factors through distinct patterns and transitions may help us better optimize and utilize intervention resources to alleviate symptoms from bullying victims.


Assuntos
Bullying , Vítimas de Crime , Transtornos de Estresse Pós-Traumáticos , Masculino , Criança , Humanos , Adolescente , Feminino , Transtornos de Estresse Pós-Traumáticos/epidemiologia , Depressão/epidemiologia , Estudos Longitudinais , Comorbidade
10.
J Transl Med ; 20(1): 262, 2022 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-35672760

RESUMO

BACKGROUND: Previous studies have indicated that chronic emotional stressors likely participate in the occurrence of cancers. However, direct evidence connecting stress and colorectal cancer development remains almost completely unexplored. METHODS: Chronic stress mouse model was used to investigate the influence of stress on tumorigenesis. Several major agonists and antagonists of adrenergic receptors were applied to investigate the effects of ß-adrenergic signaling on the development of CRC. Chromatin immunoprecipitation assays (CHIP) were used to investigate the binding of p53 and CEBPB to TRIM2 promoter. Mammosphere cultures, Cell Counting Kit-8 (CCK-8) assay, colony-formation assay, scratch wound healing assays, qPCR, immunofluorescence, coimmunoprecipitation and western blotting were used to explore the effect of stress-induced epinephrine on the CEBPB/TRIM2/P53 axis and the progress of CRC cells. RESULTS: In this study, we found that stress-induced epinephrine (EPI) promotes the proliferation, metastasis and CSC generation of CRC primarily through the ß2-adrenergic receptor. Furthermore, our studies also confirmed that chronic stress decreased the stability of p53 protein by promoting p53 ubiquitination. Results of transcriptome sequencing indicated that TRIM2 was overexpressed in cells treated with EPI. Further studies indicated that TRIM2 could regulate the stability of p53 protein by promoting p53 ubiquitination. Finally, we further proved that CEBPB was regulated by EPI and acts as the upstream transcription factor of TRIM2. CONCLUSIONS: Our studies proved that stress-induced EPI promotes the development and stemness of CRC through the CEBPB/TRIM2/P53 axis.


Assuntos
Neoplasias Colorretais , Proteína Supressora de Tumor p53 , Animais , Proteína beta Intensificadora de Ligação a CCAAT/metabolismo , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Neoplasias Colorretais/patologia , Epinefrina/farmacologia , Transição Epitelial-Mesenquimal , Regulação Neoplásica da Expressão Gênica , Camundongos , Proteínas com Motivo Tripartido/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Ubiquitina-Proteína Ligases/metabolismo
11.
Exp Dermatol ; 31(3): 320-329, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34623712

RESUMO

Abnormal activation of fibroblasts plays a crucial role in keloid development. However, the mechanism of fibroblast activation remains to be determined. YAP/TAZ are key molecules in the Hippo signalling pathway that promote cell proliferation and inhibit apoptosis. Here, we show that keloid fibroblasts have higher levels of YAP/TAZ mRNA and proteins on primary culture. Targeted knockdown of endogenous YAP or TAZ significantly inhibited cell proliferation, reduced cell migration, induced cell apoptosis and down-regulated collagen1a1 production by keloid fibroblasts. Moreover, we demonstrate that verteporfin, an inhibitor of YAP/TAZ, has similar but stronger inhibitory effects on fibroblasts compared to YAP/TAZ knockdown. Our study provides evidence that YAP/TAZ may be involved in the pathogenesis of keloids. Targeted inhibition of YAP/TAZ could change the biological behaviours of fibroblasts and can potentially be used as therapy for keloids.


Assuntos
Queloide , Fibroblastos/metabolismo , Humanos , Queloide/metabolismo , Fatores de Transcrição/genética , Proteínas com Motivo de Ligação a PDZ com Coativador Transcricional , Verteporfina/metabolismo , Verteporfina/farmacologia
12.
Inorg Chem ; 61(21): 8112-8116, 2022 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-35588277

RESUMO

A rare 3D Indium-containing polyoxoniobate framework {H9[Cu(en)2(H2O)2][Cu(en)2]12[In(en)]5[Nb23-O65(OH)3(H2O)2]{Nb24O67(OH)2(H2O)3]2}·68H2O(1), based on the In-containing polyoxoniobate cluster, {[In(en)]5[Nb23O65(OH)3(H2O)2][Nb24O67(OH)2(H2O)3]2}35- ({In5Nb71}) and [Cu(en)2]2+ linkers has been successfully synthesized. The nest-like cluster {In5Nb71} is constructed from one brand-new V-shaped {Nb23O70}, two triangle-shaped {Nb24O72} and five [In(en)]3+. The [In(en)] fragments link {Nb24O72} and {Nb23O70} units into unique {In5Nb71}n helical pillars. The copper-amine complexes connect the {In5Nb71}n helical pillars into a three-dimensional (3D) inorganic-organic hybrid In-Cu-containing framework. This material also exhibits good ionic conductivity and vapor adsorption capacity properties.

13.
J Phycol ; 58(6): 815-828, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36308470

RESUMO

Host-related microbiota are critically important for the adaptation/acclimation of hosts to changing environments, but how environmental factors and host characteristics shape the microbial communities remains largely unknown. We investigated the effects of temperature on habitat-forming macroalgae and their associated bacterial communities. Three Sargassum species (S. horneri, S. fusiforme, and S. thunbergii) and seawater samples were sampled in Gouqi Island, China, and these macroalgal samples were incubated at different temperatures (10, 20, and 27°C) for 7 d. Bacterial communities were identified from the 16S rRNA gene V3-V4 regions. The algae-associated bacterial communities of the field samples were significantly different from seawater, implying host specificity. During laboratory incubation, decreased physiological status (photosynthetic rate and oxidative stress response) was detected for all the species at 10°C, especially with regard to S. horneri and S. fusiforme. For each host, associated bacterial communities at 20 and 27°C clustered closely, and these were separated from samples at 10°C based on constrained PCoA analyses. Permutational multivariate analysis of variance revealed that algae-associated bacterial communities were more affected by host species (23.3%) than by temperature (2.48%) during laboratory incubation. The changes in bacterial community composition may be influenced by algae metabolites, which should be tested in a future study. These results further contribute to our understanding of algal microbiome changes in response to environmental changes.


Assuntos
Microbiota , Sargassum , Sargassum/fisiologia , Temperatura , RNA Ribossômico 16S/genética , Especificidade de Hospedeiro , Bactérias/genética
14.
Appl Microbiol Biotechnol ; 106(13-16): 5197-5209, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35779098

RESUMO

Recent studies have provided compelling evidence linking the composition of the gut microbiota, host diet, and host physiology. Prebiotics are substrates that are selectively utilized by host microorganisms, conferring health benefits. Prebiotics, such as prebiotic blends (PB), are commonly used worldwide in food processing. Here, microbiome-metabolomics was used to evaluate how PB affect gut microbes and metabolic functions in C57BL/6 J mice administered cefixime. We found favorable effects of PB on obesity outcomes. PB supplementation significantly increased the abundance of Bifidobacterium, Parabacteroides, Alloprevotella, Alistipes, and Dubosiella, and decreased that of Robinsoniella, Blautia, Lachnoclostridium, Coprobacillus, Hungatella, Erysipelatoclostridium, Helicobacter, Clostridium sensu stricto 1, Enterococcus, and Akkermansia compared to that in the cefixime administration (CEF) group. In particular, PB increased the abundance of Parabacteroides goldsteinii and suppressed that of Robinsoniella peoriensis and Akkermansia muciniphila. In addition, it regulated the levels of microbial metabolites such as unsaturated fatty acids and bile acids. Thus, PB can alleviate metabolic disorders induced by antibiotic intervention, indicating a potential dietary strategy for populations with antibiotic-associated diarrhea. KEY POINTS: • Prebiotic blends significantly increased the Parabacteroides goldsteinii colony. • Prebiotic blends selectivity reversed this increase of Akkermansia muciniphila by antibiotic intervention. • Prebiotic blends relieve cefixime-induced alteration of intestinal flora by regulating metabolites, such as fatty acids and bile acids.


Assuntos
Microbioma Gastrointestinal , Prebióticos , Akkermansia , Animais , Antibacterianos/farmacologia , Bacteroidetes , Ácidos e Sais Biliares/farmacologia , Cefixima/farmacologia , Modelos Animais de Doenças , Camundongos , Camundongos Endogâmicos C57BL , Verrucomicrobia
15.
Mar Drugs ; 20(11)2022 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-36355019

RESUMO

Phycocyanin is an excellent antioxidant with anti-inflammatory effects on which recent studies are growing; however, its specific target remains unclear. Linear tetrapyrrole compounds such as bilirubin have been shown to lead to the induction of heme oxygenase 1 expression in vivo, thus achieving antioxidant and anti-inflammatory effects. Phycocyanin is bound internally with linear tetrapyrrole phycocyanobilin in a similar structure to bilirubin. We speculate that there is probably a way of inducing the expression of heme oxygenase 1, with which tissue oxidative stress and inflammation can be inhibited, thus inhibiting pulmonary fibrosis caused by oxidative damage and inflammation of lung. By optimizing the enzymatic hydrolysis process, phycocyanobilin-bound phycocyanin peptide were obtained, and its in vitro antioxidant, anti-inflammatory, and anti-pulmonary fibrosis activities were investigated. The results show that the phycocyanobilin peptide was able to alleviate oxidative and inflammatory damage in cells through the Keap1-Nrf2-HO-1 pathway, which in turn relieved pulmonary fibrosis symptoms.


Assuntos
Heme Oxigenase-1 , Ficocianina , Humanos , Ficocianina/farmacologia , Ficocianina/uso terapêutico , Ficocianina/metabolismo , Heme Oxigenase-1/metabolismo , Proteína 1 Associada a ECH Semelhante a Kelch/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Antioxidantes/metabolismo , Estresse Oxidativo , Inflamação/tratamento farmacológico , Bilirrubina/metabolismo , Bilirrubina/farmacologia , Bilirrubina/uso terapêutico , Anti-Inflamatórios/farmacologia , Tetrapirróis/farmacologia , Tetrapirróis/uso terapêutico , Fibrose
16.
Artigo em Inglês | MEDLINE | ID: mdl-35834146

RESUMO

The study aimed to examine the mechanism underlying the effect of basic psychological needs satisfaction (BPNs) on depression via feelings of safety or rumination in adolescents during the COVID-19 pandemic. Self-report questionnaires were distributed to 683 middle school students from Hubei province in China. Structural Equation Modelling was used to analyse the data. The results showed that basic psychological needs satisfaction exerted negative effects on adolescents' depression in both a direct and an indirect way. In specific, basic psychological needs satisfaction not only directly reduced depression, but also indirectly reduced depression by the mediating role of feelings of safety, but not by rumination. Moreover, autonomy and relatedness, but not competence need satisfaction, indirectly reduced depression by the multiple mediating path from feelings of safety to rumination. The findings indicate satisfaction of basic psychological needs is important in increasing adolescents' feelings of safety, reducing negative cognitions, and alleviating their depression level during the pandemic.

17.
Environ Res ; 194: 110680, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33385389

RESUMO

Penthiopyrad is a chiral carboxamide fungicide with a broad spectrum of fungicidal activity. However, there is no report on the analysis of the enantiomers of penthiopyrad and their environmental behavior. Soil is an important carrier for pesticides to affect the environment. Therefore, this study aimed to investigate the absolute configuration, stereoselective degradation, configuration stability and potential metabolites of this agrochemical in soil under different laboratory conditions. R-(-)-penthiopyrad and S-(+)-penthiopyrad were identified by the electronic circular dichroism method. Regarding the racemic analyte, the degradation half-lives of the stereoisomers ranged from 38.9 to 97.6 days, the S-(+)-stereoisomer degraded preferentially in four types of Chinese soil. However, enantiopure R-(-)-penthiopyrad degraded faster than its antipode, a finding that might be related to the microbial activity in soil. The organic matter (OM) content influenced the stereoselective degradation of rac-penthiopyrad. No configuration conversion was observed in both enantiopure analyte degradation processes. One possible metabolite, 753-A-OH, was detected in the treated soil samples, and the degradation pathway might be a hydroxylation reaction. This is the first report of the absolute configuration of penthiopyrad stereoisomers and the first comprehensive evaluation of the stereoselective degradation of penthiopyrad in Chinese soil. Stereoselective degradation of rac-penthiopyrad was observed in the four types of soil. And the stereoselectivity might be inhibited by OM. This study provides more accurate data to investigate the environmental behavior of penthiopyrad at the stereoisomer level.


Assuntos
Fungicidas Industriais , Poluentes do Solo , Agroquímicos , Antifúngicos , Pirazóis , Solo , Poluentes do Solo/análise , Tiofenos
18.
Mar Drugs ; 19(10)2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34677475

RESUMO

During the processes of primary and secondary endosymbiosis, different microalgae evolved to synthesis different storage polysaccharides. In stramenopiles, the main storage polysaccharides are ß-1,3-glucan, or laminarin, in vacuoles. Currently, laminarin is gaining considerable attention due to its application in the food, cosmetic and pharmaceuticals industries, and also its importance in global biogeochemical cycles (especially in the ocean carbon cycle). In this review, the structures, composition, contents, and bioactivity of laminarin were summarized in different algae. It was shown that the general features of laminarin are species-dependence. Furthermore, the proposed biosynthesis and catabolism pathways of laminarin, functions of key genes, and diel regulation of laminarin were also depicted and comprehensively discussed for the first time. However, the complete pathways, functions of genes, and diel regulatory mechanisms of laminarin require more biomolecular studies. This review provides more useful information and identifies the knowledge gap regarding the future studies of laminarin and its applications.


Assuntos
Glucanos/metabolismo , Polissacarídeos/metabolismo , Estramenópilas , Animais , Organismos Aquáticos , Produtos Biológicos/química , Glucanos/química , Polissacarídeos/química , Relação Estrutura-Atividade
19.
Biomed Chromatogr ; 35(7): e5097, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33608928

RESUMO

This study established and validated a simple and sensitive analytical approach for determining pinoxaden residues in soil. The dissipation and adsorption-desorption of pinoxaden in four kinds of Chinese soil were comprehensively investigated for the first time, and the possible metabolic products and pathways were identified. The developed method was successfully applied in dissipation and adsorption-desorption trials. Several influential factors, including temperature, organic matter, and moisture content, affected the dissipation rate of pinoxaden in soil. During the dissipation process, 1 hydrolytic intermediate and 13 possible transformation products were identified, and predicted metabolic pathways were composed of electron rearrangement, oxidation, cyclization, carboxylation, and so on. Both the adsorption and desorption isotherms of pinoxaden in four kinds of Chinese soil followed the Freundlich equation, and the Freundlich Kf values were positively correlated with the soil cation exchange capacity. According to the calculated Gibbs free energies, the adsorption of pinoxaden was an endothermic reaction and mainly a physical process. These results could provide some useful data for the determination of pinoxaden in other matrices and the evaluation of the environmental fate of pinoxaden in soil and other ecosystems.


Assuntos
Compostos Heterocíclicos com 2 Anéis/análise , Poluentes do Solo/análise , Adsorção , China , Cromatografia Líquida , Compostos Heterocíclicos com 2 Anéis/química , Limite de Detecção , Modelos Lineares , Reprodutibilidade dos Testes , Poluentes do Solo/química , Espectrometria de Massas em Tandem , Temperatura
20.
J Sci Food Agric ; 101(13): 5498-5507, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33682088

RESUMO

BACKGROUND: Thiophanate-methyl and its metabolite carbendazim are broad-spectrum fungicides used on many crops. The residues of these chemicals could result in potential environmental and human health problems. Therefore, investigations of the dissipation and residue behaviors of thiophanate-methyl and its metabolite carbendazim on cowpeas and associated dietary risk assessments are essential for the safety of agricultural products. RESULTS: A simple analytical approach using liquid chromatography with tandem mass spectrometry was developed and validated for the determination of thiophanate-methyl and carbendazim concentrations in cowpeas. Good linearity (R2 > 0.998) was obtained, and the recoveries and relative standard deviations were 80.0-104.7% and 1.4-5.2%, respectively. The dissipation rates of thiophanate-methyl, carbendazim and total carbendazim were high (half-lives of 1.61-2.46 days) and varied in the field cowpea samples because of the different weather conditions and planting patterns. Based on the definition of thiophanate-methyl, the terminal residues of total carbendazim in cowpea samples were below the maximum residue limits set by Japan for other legumes. The acute and chronic risk quotients of three analytes were 0.0-27.6% in cowpea samples gathered from all terminal residue treatments, which were below 100%. CONCLUSION: An optimized approach for detecting thiophanate-methyl and carbendazim in cowpeas was applied for the investigation of field-trial samples. The potential acute and chronic dietary risks of thiophanate-methyl, carbendazim and total carbendazim to the health of Chinese consumers were low. These results could guide the safe and proper use of thiophanate-methyl in cowpeas and offer data for the dietary risk assessment of thiophanate-methyl in cowpeas. © 2021 Society of Chemical Industry.


Assuntos
Benzimidazóis/análise , Carbamatos/análise , Contaminação de Alimentos/análise , Fungicidas Industriais/química , Resíduos de Praguicidas/química , Tiofanato/química , Vigna/química , Benzimidazóis/metabolismo , Carbamatos/metabolismo , China , Fungicidas Industriais/metabolismo , Cinética , Resíduos de Praguicidas/metabolismo , Sementes/química , Sementes/crescimento & desenvolvimento , Sementes/metabolismo , Tiofanato/metabolismo , Vigna/crescimento & desenvolvimento , Vigna/metabolismo
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