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1.
Cell ; 187(15): 3936-3952.e19, 2024 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-38936359

RESUMO

Duplication is a foundation of molecular evolution and a driver of genomic and complex diseases. Here, we develop a genome editing tool named Amplification Editing (AE) that enables programmable DNA duplication with precision at chromosomal scale. AE can duplicate human genomes ranging from 20 bp to 100 Mb, a size comparable to human chromosomes. AE exhibits activity across various cell types, encompassing diploid, haploid, and primary cells. AE exhibited up to 73.0% efficiency for 1 Mb and 3.4% for 100 Mb duplications, respectively. Whole-genome sequencing and deep sequencing of the junctions of edited sequences confirm the precision of duplication. AE can create chromosomal microduplications within disease-relevant regions in embryonic stem cells, indicating its potential for generating cellular and animal models. AE is a precise and efficient tool for chromosomal engineering and DNA duplication, broadening the landscape of precision genome editing from an individual genetic locus to the chromosomal scale.


Assuntos
Duplicação Gênica , Edição de Genes , Genoma Humano , Humanos , Edição de Genes/métodos , Sistemas CRISPR-Cas/genética , DNA/genética , Animais , Células-Tronco Embrionárias/metabolismo , Cromossomos Humanos/genética
2.
EMBO J ; 43(10): 1990-2014, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38605226

RESUMO

Prenatal lethality associated with mouse knockout of Mettl16, a recently identified RNA N6-methyladenosine (m6A) methyltransferase, has hampered characterization of the essential role of METTL16-mediated RNA m6A modification in early embryonic development. Here, using cross-species single-cell RNA sequencing analysis, we found that during early embryonic development, METTL16 is more highly expressed in vertebrate hematopoietic stem and progenitor cells (HSPCs) than other methyltransferases. In Mettl16-deficient zebrafish, proliferation capacity of embryonic HSPCs is compromised due to G1/S cell cycle arrest, an effect whose rescue requires Mettl16 with intact methyltransferase activity. We further identify the cell-cycle transcription factor mybl2b as a directly regulated by Mettl16-mediated m6A modification. Mettl16 deficiency resulted in the destabilization of mybl2b mRNA, likely due to lost binding by the m6A reader Igf2bp1 in vivo. Moreover, we found that the METTL16-m6A-MYBL2-IGF2BP1 axis controlling G1/S progression is conserved in humans. Collectively, our findings elucidate the critical function of METTL16-mediated m6A modification in HSPC cell cycle progression during early embryonic development.


Assuntos
Células-Tronco Hematopoéticas , Metiltransferases , Metilação de RNA , Proteínas de Ligação a RNA , Fatores de Transcrição , Peixe-Zebra , Animais , Humanos , Camundongos , Adenosina/análogos & derivados , Adenosina/metabolismo , Adenosina/genética , Ciclo Celular , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ciclo Celular/genética , Proliferação de Células , Desenvolvimento Embrionário/genética , Regulação da Expressão Gênica no Desenvolvimento , Células-Tronco Hematopoéticas/metabolismo , Células-Tronco Hematopoéticas/citologia , Metiltransferases/metabolismo , Metiltransferases/genética , Proteínas de Ligação a RNA/metabolismo , Proteínas de Ligação a RNA/genética , Peixe-Zebra/metabolismo , Peixe-Zebra/embriologia , Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo , Proteínas de Peixe-Zebra/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Metilação de RNA/genética
3.
J Biol Chem ; 300(3): 105772, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38382674

RESUMO

Pre-mRNA splicing is a precise regulated process and is crucial for system development and homeostasis maintenance. Mutations in spliceosomal components have been found in various hematopoietic malignancies (HMs) and have been considered as oncogenic derivers of HMs. However, the role of spliceosomal components in normal and malignant hematopoiesis remains largely unknown. Pre-mRNA processing factor 31 (PRPF31) is a constitutive spliceosomal component, which mutations are associated with autosomal dominant retinitis pigmentosa. PRPF31 was found to be mutated in several HMs, but the function of PRPF31 in normal hematopoiesis has not been explored. In our previous study, we generated a prpf31 knockout (KO) zebrafish line and reported that Prpf31 regulates the survival and differentiation of retinal progenitor cells by modulating the alternative splicing of genes involved in mitosis and DNA repair. In this study, by using the prpf31 KO zebrafish line, we discovered that prpf31 KO zebrafish exhibited severe defects in hematopoietic stem and progenitor cell (HSPC) expansion and its sequentially differentiated lineages. Immunofluorescence results showed that Prpf31-deficient HSPCs underwent malformed mitosis and M phase arrest during HSPC expansion. Transcriptome analysis and experimental validations revealed that Prpf31 deficiency extensively perturbed the alternative splicing of mitosis-related genes. Collectively, our findings elucidate a previously undescribed role for Prpf31 in HSPC expansion, through regulating the alternative splicing of mitosis-related genes.


Assuntos
Fatores de Processamento de RNA , Proteínas de Peixe-Zebra , Peixe-Zebra , Animais , Desenvolvimento Embrionário , Mutação , Precursores de RNA/metabolismo , Fatores de Processamento de RNA/metabolismo , Células-Tronco/metabolismo , Peixe-Zebra/genética , Peixe-Zebra/crescimento & desenvolvimento , Peixe-Zebra/metabolismo , Proteínas de Peixe-Zebra/metabolismo
4.
Nano Lett ; 2024 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-39172999

RESUMO

Low-power and fast artificial neural network devices represent the direction in developing analogue neural networks. Here, an ultralow power consumption (0.8 fJ) and rapid (100 ns) La0.1Bi0.9FeO3/La0.7Sr0.3MnO3 ferroelectric tunnel junction artificial synapse has been developed to emulate the biological neural networks. The visual memory and forgetting functionalities have been emulated based on long-term potentiation and depression with good linearity. Moreover, with a single device, logical operations of "AND" and "OR" are implemented, and an artificial neural network was constructed with a recognition accuracy of 96%. Especially for noisy data sets, the recognition speed is faster after preprocessing by the device in the present work. This sets the stage for highly reliable and repeatable unsupervised learning.

5.
J Am Chem Soc ; 146(21): 14528-14538, 2024 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-38742912

RESUMO

Composite oxides have been widely applied in the hydrogenation of CO/CO2 to methanol or as the component of bifunctional oxide-zeolite for the synthesis of hydrocarbon chemicals. However, it is still challenging to disentangle the stepwise formation mechanism of CH3OH at working conditions and selectively convert CO2 to hydrocarbon chemicals with narrow distribution. Here, we investigate the reaction network of the hydrogenation of CO2 to methanol over a series of spinel oxides (AB2O4), among which the Zn-based nanostructures offer superior performance in methanol synthesis. Through a series of (quasi) in situ spectroscopic characterizations, we evidence that the dissociation of H2 tends to follow a heterolytic pathway and that hydrogenation ability can be regulated by the combination of Zn with Ga or Al. The coordinatively unsaturated metal sites over ZnAl2Ox and ZnGa2Ox originating from oxygen vacancies (OVs) are evidenced to be responsible for the dissociative adsorption and activation of CO2. The evolution of the reaction intermediates, including both carbonaceous and hydrogen species at high temperatures and pressures over the spinel oxides, has been experimentally elaborated at the atomic level. With the integration of a series of zeolites or zeotypes, high selectivities of hydrocarbon chemicals with narrow distributions can be directly produced from CO2 and H2, offering a promising route for CO2 utilization.

6.
Rev Cardiovasc Med ; 25(5): 171, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-39076470

RESUMO

Background: Secreted frizzled-related protein 2 (sFRP2) is involved in various cardiovascular diseases. However, its relevance in left ventricular (LV) remodeling in patients with hypertension (HTN) is obscure. Methods: In this study, 196 patients with HTN were included, 59 with echocardiographic LV remodeling. A total of 100 healthy subjects served as normal controls. The serum-sFRP2 level was measured by enzyme-linked immunosorbent assay (ELISA). Data were collected from medical records for baseline characteristics, biochemistry tests, and echocardiography. Receiver operating characteristic (ROC) curves were used to assess the distinguishing value of sFRP2 for LV remodeling in patients with HTN. Spearman rank correlation analysis was utilized to identify factors correlated with sFRP2. Cardiac sFRP2 was determined by Western blot and quantitative polymerase chain reaction (qPCR). Results: The level of serum-sFRP2 was higher in HTN patients with echocardiographic LV remodeling than their non-remodeling counterparts. ROC analysis showed that the area under the curve (AUC) for sFRP2 in distinguishing echocardiographic LV remodeling in HTN patients was 0.791 (95% confidence interval (CI): 0.714-0.869). The sFRP2 was negatively correlated with LV dimension and positively correlated with relative wall thickness (RWT). The expression of sFRP2 was higher in hypertrophic hearts, which could be reversed by myricetin. Conclusions: The serum level and cardiac sFRP2 increased in the setting of LV remodeling and decreased by myricetin. Serum sFRP2 may be a promising distinguishing factor for LV remodeling in HTN patients.

7.
Cancer Cell Int ; 24(1): 86, 2024 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-38402174

RESUMO

BACKGROUND: The role of Acyl-CoA dehydrogenase long chain (ACADL) in different tumor types had different inhibiting or promoting effect. However, its role in non-small cell lung cancer (NSCLC) carcinogenicity is not clear. METHOD: In this study, we utilized The Cancer Genome Atlas (TCGA) database to analyze ACADL expression in NSCLC and its correlation with overall survival. Furthermore, we investigated the function of ACADL on cellular proliferation, invasion, colony, apoptosis, cell cycle in vitro with NSCLC cells. Mechanistically, we evaluated the regulatory effect of ACADL expression on its downstream factor yes-associated protein (YAP) by assessing YAP phosphorylation levels and its cellular localization. Finally, we verified the tumorigenic effect of ACADL on NSCLC cells through xenograft experiments in vivo. RESULTS: Compared to adjacent non-cancerous samples, ACADL significantly down-regulated in NSCLC. Overexpression of ACADL, effectively reduced the proliferative, colony, and invasive capabilities of NSCLC cells, while promoting apoptosis and inducing cell cycle arrest. Moreover, ACADL overexpression significantly enhanced YAP phosphorylation and hindered its nuclear translocation. However, the inhibitory effect of the overexpression of ACADL in NSCLC cells mentioned above can be partially counteracted by YAP activator XMU-MP-1 application both in vitro and in vivo. CONCLUSION: The findings suggest that ACADL overexpression could suppress NSCLC development by modulating YAP phosphorylation and limiting its nuclear shift. This role of ACADL-YAP axis provided novel insights into NSCLC carcinogenicity and potential therapeutic strategies.

8.
Chemistry ; : e202400963, 2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-38923685

RESUMO

The development of innovative methods for synthesizing silylcyclopentene compounds is particularly important for enriching and improving the synthetical toolbox of organosilicon compounds. Herein, a facile approach has been developed for the synthesis of silylcyclopentenes promoted by mechanochemically generated organolithium species as silicon nucleophiles under ball milling conditions, avoiding the requirement of large amounts of bulk solvent. This operationally simple method demonstrates good functional group compatibility, which provides a great opportunity for further exploration of the synthetic applications of silylcyclopentenes. Density functional theory calculations indicated that the transient lithiosilole intermediates undergo a stepwise nucleophilic addition process, which governs this mechanic-force-promoted [4+1] cycloaddition reaction.

9.
Mol Cell Biochem ; 2024 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-39117976

RESUMO

Pancreatic ductal adenocarcinoma (PDAC) is characterized by poor prognosis primarily due to metastasis. Accumulating evidence suggests that PLEK2 acts as an oncogene in various tumors. This study aimed to investigate the effects of PLEK2 on PDAC. Expression analysis of PLEK2 was conducted using qRT-PCR, Western blot, and immunohistochemistry in PDAC. Wound healing and transwell assays were performed to evaluate the impact of PLEK2 on cell migration and invasion. A xenograft tumor model was employed to assess the in vivo proliferation of PLEK2. Additionally, the downstream pathway of PLEK2 was analyzed through RNA-seq and confirmed by Western blot analysis. The results demonstrated the upregulation of PLEK2 expression in tumor specimens. High PLEK2 expression was significantly associated with poor overall survival and advanced TNM stages. Correlation analyses revealed positive correlations between PLEK2 and TGF-ß, EGFR, and MMP1. Wound healing and transwell assays demonstrated that PLEK2 promoted PDAC cell migration and invasion, potentially through the activation of the epithelial-to-mesenchymal transition process. The in vivo experiment further confirmed that PLEK2 knockdown suppressed tumor growth. RNA-seq analysis revealed PLEK2's regulation of MMP1 and activation of p-ERK and p-STAT3, which were verified by Western blot analysis. Overall, the present study suggests that PLEK2 may play a tumor-promoting role in PDAC. These findings provide valuable insights into the molecular mechanisms of pancreatic cancer and highlight the potential of PLEK2 as a therapeutic target.

10.
J Org Chem ; 89(9): 6345-6352, 2024 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-38602779

RESUMO

An improved protocol has been developed for the direct sulfonamidation of unactivated alkyl alcohols using In(OTf)3 as a Lewis acid catalyst. Although the established methods using Lewis or Brønsted acids have been well-studied for the direct functionalization of alcohols, their substrate scope mainly focuses on the π-activated alcohols. In this reaction, unactivated aliphatic alcohols were evaluated and afforded the desired sulfonamide products with good to excellent yields.

11.
J Org Chem ; 2024 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-39162099

RESUMO

Although the synthesis of polycyclic (hetero)aromatics via the [4 + 2] benzannulation process has been thoroughly explored, the restricted availability of energy sources (including thermal, light, and electrical energy) mandates the utilization of substantial quantities of organic solvents, inevitably leading to environmental pollution, resource wastage, and low reaction efficiency. Herein, we report a new method for the synthesis of polycyclic (hetero)aromatics from diazonium salts and alkynes under ball-milling conditions. This mechanochemical approach requires only substoichiometric amounts of DMSO as a liquid-assisted grinding additive and furnishes the desired product in a short time.

12.
J Org Chem ; 89(5): 3573-3579, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38377489

RESUMO

A BF3·OEt2-catalyzed synthesis of carboranylated dihydropyrrolo[1,2-a]quinoxalines and dihydroindolo[1,2-a]quinoxalines in 30-99% yields is presented through the heterocyclization of various C-modified C-formyl-o-carboranes with 1-(2-aminophenyl)-pyrroles/indoles. A systematic comparative investigation of their oxidation stability in air confirmed that 4-carboranyl-4,5-dihydropyrrolo[1,2-a]quinoxaline had better stability than the 4-phenyl analogue. A cage-deboronation reaction for N-acetyl-substituted carboranylated dihydropyrrolo[1,2-a]quinoxaline produced the corresponding 7,8-nido-carborane cesium salt. A kinetic resolution was also realized to obtain an optically pure carboranylated N-heterocycle scaffold bearing a carborane cage carbon-bonded chiral stereocenter.

13.
Aging Male ; 27(1): 2346312, 2024 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38685728

RESUMO

BACKGROUND: Previous research has shown that testosterone deficiency (TD) increases the risk of anemia, but it is unclear whether anemia affects testosterone levels. This study investigated the influence of anemia on testosterone levels. METHODS: Utilizing data from six NHANES cycles, including demographic, testosterone levels, and hemoglobin concentrations, we employed multivariable-adjusted logistic regression to investigate the relationship between anemia and testosterone levels. Moreover, a two-sample Mendelian randomization (MR) study employing genome-wide association study (GWAS) data examined the causal relationship. Kaplan-Meier survival estimation was used to compared the overall survival (OS) of anemic and nonanemic patients with low testosterone and normal testosterone levels. RESULTS: The inclusion of 21,786 participants (2318 with anemia and19,468 without anemia) revealed that nonanemic patients exhibited higher testosterone levels than did anemic patients (ß = 22.616, 95% CI: 3.873-41.359, p = 0.01807). MR analysis confirmed anemia as a cause of TD (OR = 1.045, 95% CI: 1.020-1.071, p < 0.001). Anemic males with low testosterone had reduced OS compared to those with normal levels (p < 0.001). CONCLUSIONS: Anemia emerged as a potential risk factor for TD, highlighting a bidirectional relationship between these conditions. Additional prospective investigations are essential for the validation and reinforcement of our findings.


Assuntos
Anemia , Estudo de Associação Genômica Ampla , Análise da Randomização Mendeliana , Inquéritos Nutricionais , Testosterona , Humanos , Testosterona/sangue , Testosterona/deficiência , Masculino , Anemia/genética , Anemia/epidemiologia , Pessoa de Meia-Idade , Adulto , Idoso , Fatores de Risco
14.
Surg Endosc ; 2024 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-38958719

RESUMO

BACKGROUND: Laparoscopic pancreatoduodenectomy (LPD) is one of the most challenging operations and has a long learning curve. Artificial intelligence (AI) automated surgical phase recognition in intraoperative videos has many potential applications in surgical education, helping shorten the learning curve, but no study has made this breakthrough in LPD. Herein, we aimed to build AI models to recognize the surgical phase in LPD and explore the performance characteristics of AI models. METHODS: Among 69 LPD videos from a single surgical team, we used 42 in the building group to establish the models and used the remaining 27 videos in the analysis group to assess the models' performance characteristics. We annotated 13 surgical phases of LPD, including 4 key phases and 9 necessary phases. Two minimal invasive pancreatic surgeons annotated all the videos. We built two AI models for the key phase and necessary phase recognition, based on convolutional neural networks. The overall performance of the AI models was determined mainly by mean average precision (mAP). RESULTS: Overall mAPs of the AI models in the test set of the building group were 89.7% and 84.7% for key phases and necessary phases, respectively. In the 27-video analysis group, overall mAPs were 86.8% and 71.2%, with maximum mAPs of 98.1% and 93.9%. We found commonalities between the error of model recognition and the differences of surgeon annotation, and the AI model exhibited bad performance in cases with anatomic variation or lesion involvement with adjacent organs. CONCLUSIONS: AI automated surgical phase recognition can be achieved in LPD, with outstanding performance in selective cases. This breakthrough may be the first step toward AI- and video-based surgical education in more complex surgeries.

15.
BMC Public Health ; 24(1): 1772, 2024 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-38961338

RESUMO

OBJECTIVE: Shift work and Shift Work Sleep Disorder (SWSD) are known to affect the secretion of several neurotransmitters and hormones associated with premature ejaculation (PE). However, their specific influence on the regulation of male ejaculation remains unclear. This study explores the relationship between shift work, SWSD, and PE. METHODS: From April to October 2023, a cross-sectional survey was conducted across five regions of China to explore the work schedules, sleep quality, and sexual function of male workers. Participants' sleep quality was evaluated using a validated SWSD questionnaire, and their erectile function and ejaculatory control were assessed with the International Inventory of Erectile Function (IIEF-5) scores and Premature Ejaculation Diagnostic Tool (PEDT) scores, respectively. Univariate and multivariate linear regression analyses were employed to identify risk factors associated with PE. Confounders were controlled using multiple regression models, and clinical prediction models were developed to predict PE onset and assess the contribution of risk factors. RESULTS: The study included 1239 eligible participants, comprising 840 non-shift workers and 399 shift workers (148 with SWSD and 251 without SWSD). Compared to non-shift working males, those involved in shift work (ß 1.58, 95% CI 0.75 - 2.42, p < 0.001) and those suffering from SWSD (ß 2.86, 95% CI 1.86 - 3.85, p < 0.001) they had significantly higher PEDT scores. Additionally, we identified daily sleep of less than six hours, depression, anxiety, diabetes, hyperlipidemia, frequent alcohol consumption (more than twice a week), and erectile dysfunction as risk factors for PE. The predictive model for PE demonstrated commendable efficacy. CONCLUSION: Both shift work and SWSD significantly increase the risk of premature ejaculation, with the risk magnifying in tandem with the duration of shift work. This study reveals the potential impact of shift work and SWSD on PE and provides new theoretical foundations for the risk assessment and prevention of this condition.


Assuntos
Ejaculação Precoce , Jornada de Trabalho em Turnos , Transtornos do Sono do Ritmo Circadiano , Humanos , Masculino , Ejaculação Precoce/epidemiologia , Adulto , Estudos Transversais , Jornada de Trabalho em Turnos/efeitos adversos , China/epidemiologia , Transtornos do Sono do Ritmo Circadiano/epidemiologia , Pessoa de Meia-Idade , Fatores de Risco , Inquéritos e Questionários , Adulto Jovem
16.
BMC Surg ; 24(1): 233, 2024 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-39152385

RESUMO

OBJECTIVE: Achieving textbook outcome (TO) implies a smooth recovery post-operation without specified composite complications. This study aimed to evaluate TO in laparoscopic pancreaticoduodenectomy (LPD) and identify independent risk factors associated with achieving TO. METHODS: We conducted a retrospective analysis of data from a randomized controlled trial on LPD at West China Hospital (ChiCTR1900026653). Patients were categorized into the TO and non-TO groups. Perioperative variables were compared between these groups. Multivariate logistic regression was utilized to identify the risk factors. RESULTS: A total of 200 consecutive patients undergoing LPD were included in this study. TO was achieved in 82.5% (n = 165) of the patients. Female patients (OR: 2.877, 95% CI: 1.219-6.790; P = 0.016) and those with a hard pancreatic texture (OR: 2.435, 95% CI: 1.018-5.827; P = 0.046) were associated with an increased likelihood of achieving TO. CONCLUSIONS: TO can be achieved in more than 80% of patients in a high-volume LPD center. Independent risk factors associated with achieving TO included gender (male) and pancreatic texture (soft).


Assuntos
Laparoscopia , Pancreaticoduodenectomia , Humanos , Pancreaticoduodenectomia/métodos , Pancreaticoduodenectomia/efeitos adversos , Feminino , Masculino , Laparoscopia/métodos , Pessoa de Meia-Idade , Fatores de Risco , Estudos Retrospectivos , Idoso , Resultado do Tratamento , Estudos Prospectivos , China/epidemiologia , Adulto , Hospitais com Alto Volume de Atendimentos , Complicações Pós-Operatórias/epidemiologia
17.
Beilstein J Org Chem ; 20: 257-263, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38352071

RESUMO

In recent years, S-(alkyl)thianthrenium salts have become an important means of functionalizing alcohol compounds. However, additional transition metal catalysts and/or visible light are required. Herein, a direct thioetherification/amination reaction of thianthrenium salts is realized under metal-free conditions. This strategy exhibits good functional-group tolerance, operational simplicity, and an extensive range of compatible substrates.

18.
Rev Cardiovasc Med ; 24(8): 227, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39076724

RESUMO

Patients with chronic kidney disease treated by dialysis (CKD-G5D) are characterized by a high prevalence of coronary artery disease (CAD). Such patients differ from non-uremic CAD patients and have been excluded from several clinical CAD trials. CKD-G5D patients may be asymptomatic for their CAD, making their risk stratification and management challenging. This review will focus on the incidence, epidemiology, pathophysiology, screening tools, and management/treatment of CAD in CKD-G5D patients. It will also review recent studies concerning the screening tools and management strategies available for these patients. The need for improved evaluation of cardiovascular risk factors, screening and early intervention for symptomatic CAD in CKD-G5D patients will be highlighted.

20.
Environ Pollut ; 351: 124024, 2024 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-38685554

RESUMO

Organisms are generally exposed to target contaminant with stable concentrations in traditional ecotoxicological studies. However, it is difficult to truly represent the dynamics and complexity of actual aquatic pollution for risk management. Contaminants may enter nearby aquatic systems in pulsed exposure, thus resulting in that aquatic organisms will be exposed to contaminants at fluctuating concentrations. Especially during the season of summer, due to the changes in displacement or periodic emissions of veterinary antibiotics in aquaculture, algal blooms occur frequently in surrounding waters, thus leading to eutrophication of the water. Florfenicol (FFC) is currently widely used as a veterinary antibiotic, but the aquatic ecological risks of FFC under concentration fluctuations are still unknown. Therefore, the acute exposure, chronic exposure and pulsed exposure effects of FFC on Microcystis aeruginosa were investigated to comprehensively evaluate the ecological risk of FFC and raise awareness of the pulsed exposure mode. Results indicated that the toxic effects of FFC on M. aeruginosa were dominated by exposure mode, exposure duration, exposure frequency, and exposure concentration. The maximum growth inhibition rate of the 10 µg/L FFC treatment amounted to 4.07% during chronic exposure of 18 days. However, the growth inhibition rate decreased from 55.1% to 19.31% when algae was exposure to 10 µg/L FFC during the first pulsed exposure (8 h). Therefore, when the concentration of FFC was equal under chronic and pulsed exposure, FFC exhibited greater toxicity on M. aeruginosa in short pulsed exposure than in continuous exposure. In addition, repetitive pulsed exposure strengthened the resistance of M. aeruginosa on FFC. The adaptive regulation of algae was related to the duration and frequency of exposure. Above results suggested that traditional toxicity assessments lacked consideration for fluctuating concentrations during pollutant emissions, thus underestimating the environmental risk of contaminant. This investigation aims to facilitate the standardization of pulsed exposure.


Assuntos
Antibacterianos , Aquicultura , Poluentes Químicos da Água , Antibacterianos/toxicidade , Poluentes Químicos da Água/toxicidade , Poluentes Químicos da Água/análise , Microcystis/crescimento & desenvolvimento , Tianfenicol/análogos & derivados , Tianfenicol/toxicidade , Eutrofização , Monitoramento Ambiental/métodos
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