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1.
Chemosphere ; 287(Pt 1): 132028, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34474382

RESUMO

Cyanotoxins including microcystins are increasing globally, escalating health risks to humans and wildlife. Freshwater fish can accumulate and retain microcystins in tissues; however, uptake and depuration studies thus far have not exposed fish to microcystins in its intracellular state (i.e., cell-bound or conserved within cyanobacteria), which is a primary route of exposure in the field, nor have they investigated sublethal molecular-level effects in tissues, limiting our knowledge of proteins responsible for microcystin toxicity pathways in pre-to-postsenescent stages of a harmful algal bloom. We address these gaps with a 2-wk study (1 wk of 'uptake' exposure to intracellular microcystins (0-40 µg L-1) produced by Microcystis aeruginosa followed by 1 wk of 'depuration' in clean water) using Rainbow Trout (Oncorhynchus mykiss) and Lake Trout (Salvelinus namaycush). Liver and muscle samples were collected throughout uptake and depuration phases for targeted microcystin quantification and nontargeted proteomics. For both species, microcystins accumulated at a higher concentration in the liver than muscle, and activated cellular responses related to oxidative stress, apoptosis, DNA repair, and carcinogenicity. However, intraspecific proteomic effects between Rainbow Trout and Lake Trout differed, and interspecific accumulation and retention of microcystins in tissues within each species also differed. We demonstrate that fish do not respond the same to cyanobacterial toxicity within and among species despite being reared in the same environment and diet.


Assuntos
Microcistinas , Microcystis , Animais , Proliferação Nociva de Algas , Humanos , Microcistinas/toxicidade , Proteômica
2.
Chemosphere ; 287(Pt 1): 132079, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34523453

RESUMO

The presence of microcystins (MCs) in waterbodies requires a simple and reliable monitoring technique to characterize better their spatiotemporal distribution and ecological risks. An organic-diffusive gradients in thin films (o-DGT) passive sampler based on polyacrylamide diffusive gel and hydrophilic-lipophilic balance (HLB) binding gel was developed for MCs in water. The mass accumulation of three MCs (MC-LR, -RR, and -YR) was linear over 10 days (R2 ≥ 0.98). Sampling rates (2.68-3.22 mL d-1) and diffusion coefficients (0.90-1.08 × 10-6 cm2 s-1) of three MCs were obtained at 20 °C. Two different passive samplers, o-DGT and the Solid Phase Adsorption Toxin Tracking device (SPATT), were co-deployed to estimate MC levels at three lakes in California, USA. Measured total MC concentrations were up to 10.9 µg L-1, with MC-LR the primary variant at a measured maximum concentration of 2.74 µg L-1. Time-weighted average MC concentrations by o-DGT were lower than grab water samples, probably because grab sampling measures both dissolved and particulate phases (i.e., MCs in cyanobacteria). Passive water samplers by design can only measure dissolved-phase MCs, which are considerably less during the cyanobacteria-laden periods observed. Both o-DGT and grab samples gave comparable results for three MC variants at low levels of MCs, e.g., <0.1 µg L-1. o-DGT showed a higher correlation with grab sampling than SPATT did. This study demonstrates that o-DGT can be effectively used for monitoring and evaluation of dissolved MCs in waters.


Assuntos
Microcistinas , Poluentes Químicos da Água , Difusão , Monitoramento Ambiental , Água , Poluentes Químicos da Água/análise
3.
Environ Pollut ; 292(Pt A): 118354, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34648839

RESUMO

Contamination of microcystins (MCs) in plant-soil system have become a serious problem worldwide, however, it remains largely unknown how to alleviate the potential risk of consuming MCs-contaminated plants. In the present study, attapulgite, biochar and peat were used as soil amendments to reduce MCs bioaccumulation in lettuce. Lettuce irrigated with 10 µg L-1 microcystin-LR (MC-LR) were growing in two different kinds of soils with or without soil amendments. Results showed that all soil amendments effectively reduced MC-LR bioaccumulation in lettuce roots and leaves. Compared with the control treatment, the MC-LR concentrations in leaves in treatments with attapulgite, biochar and peat decreased by 41.5%, 30.6%, 57.0% in soil A and 38.9%, 43.2%, 54.7% in soil B, respectively. Peat application was most effective in reducing MC-LR bioaccumulation. The decreased soil free MC-LR concentrations were positively correlated with MC-LR concentrations in lettuce, indicating decreased bioavailability of MC-LR by soil amendments. It is noteworthy that soil total MC-LR concentration in peat treatment significantly decreased by 33.3% and 29.4% in soil A and soil B, respectively, compared with the controls. According to the results from high-throughput sequencing, peat amendment increased the α-diversity of soil bacterial community and boosted the abundance of Sphingomonas and Methylobacillus (dozens of MC-degrading bacteria belong to these genera). This was in line with the results of soil total MC-LR concentration. It can be speculated that peat application directly and/or indirectly promoted microbial degradation of MC-LR in soils. This work proposed an effective way to alleviate the potential risks of MCs contamination in plant-soil system.


Assuntos
Alface , Microcistinas , Bioacumulação , Alface/metabolismo , Toxinas Marinhas , Microcistinas/metabolismo , Solo
4.
Environ Pollut ; 292(Pt A): 118308, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34626705

RESUMO

Aggravating the pollution of microcystins (MCs) in freshwater environments is detrimental to aquatic living organisms and humans, and thus threatens the stability of ecosystems. Some environmental factors have been verified to promote the production of MCs in Microcystis aeruginosa, thereby aggravating the pollution of MCs. However, the effects of cerium (Ce), the most abundant rare earth element in global water environments, on the production of MCs in M. aeruginosa are unknown. Here, Lake Taihu water was selected as a representative of freshwater environments. By using interdisciplinary methods, it was found that: (1) the exposure level of Ce [Ce(III) and Ce(IV)] in Lake Taihu water is in the range of 0.271-0.282 µg/L; (2) Ce exposure in Lake Taihu water promoted the contents of three main MCs (MC-LR, MC-LW and MC-YR) in M. aeruginosa and water; (3) a cellular mechanism of Ce promoting the production of MCs in M. aeruginosa in Lake Taihu water was suggested: Ce enhanced endocytosis in cells of M. aeruginosa to promote the essential element uptake by M. aeruginosa for MC synthesis. Thus, Ce exposure in Lake Taihu water aggravates the pollution of MCs via enhancing endocytosis in cells of M. aeruginosa. The results provide reference for assessing the environmental risk of Ce in water environments, investigating the mechanism of the pollution of MCs induced by environmental factors, and developing strategies aimed at preventing and controlling the pollution of MCs.


Assuntos
Cério , Microcystis , Cério/toxicidade , China , Ecossistema , Endocitose , Humanos , Lagos , Microcistinas , Água
5.
Environ Pollut ; 292(Pt A): 118305, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34626715

RESUMO

Due to the large-scale outbreak of Corona Virus Disease (2019), amounts of disinfecting agents was regularly used in public environments and their potential toxicity towards organisms needed to be appreciated. Thus, one mostly used cationic disinfectant, benzalkonium chlorides (BAC(C12)), was selected to assess its potential toxicity one common cyanobacteria Microcystis aeruginosa (M. aeruginosa) in this study. The aims were to explore the toxic effect and mechanism of BAC (C12) on M. aeruginosa growth within 96 h via morphological, physiological, and the relative and absolute quantification (iTRAQ)-based quantitative proteomics variations. The results found that BAC(C12) significantly inhibited cell density of M. aeruginosa at concentrations from 1 mg/L to 10 mg/L, and the 96-h EC50 value was identified to be 3.61 mg/L. Under EC50 concentration, BAC(C12) depressed the photosynthesis activities of M. aeruginosa exhibited by 36% decline of the maximum quantum yield for primary photochemistry (Fv/Fm) value and denaturation of photosynthetic organelle, caused oxidative stress response displayed by the increase of three indexes including superoxide dismutase (SOD), malondialdehyde (MDA), and the intracellular reactive oxygen species (ROS), and destroyed the integrity of cell membranes demonstrated by TEM images and the increase of ex-cellular substances. Then, the iTRAQ-based proteomic analysis demonstrated that BAC(C12) depressed photosynthesis activities through inhibiting the expressions of photosynthetic protein and photosynthetic electron transport related proteins. The suppression of electron transport also led to the increase of superoxide radicals and then posed oxidative stress on cell. Meantime, the 63.63% ascent of extracellular microcystin production of M. aeruginosa was observed, attributing to the high expression of microcystin synthesis proteins and the damage of cell membrane. In sum, BAC(C12) exposure inhibited the growth of M. aeruginosa mainly by depressing photosynthesis, inducing oxidative stress, and breaking the cell membrane. And, it enhanced the release of microcystin from the cyanobacterial cells via up-regulating the microcystin synthesis proteins and inducing the membrane damage, which could enlarge its toxicity to aquatic species.


Assuntos
Microcystis , Compostos de Benzalcônio , Cloretos , Microcistinas/metabolismo , Microcistinas/toxicidade , Microcystis/metabolismo , Fotossíntese , Proteômica
6.
Chemosphere ; 286(Pt 3): 131950, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34426274

RESUMO

In this study, a cyclic process of adsorption and persulfate (PS) oxidation-driven regeneration using FeCl3-activated biochar (FA-BC) was suggested as a novel remediation process to remove microcystin-LR (MC-LR) from water. For enhancing overall treatment efficiency and cost effectiveness, the impacts of temperature on adsorption and PS oxidation-driven regeneration were investigated. The increase of temperature resulted in the increase of MC-LR adsorption rate on FA-BC due to the enhanced MC-LR diffusivity in water. Moreover, the MC-LR oxidation and PS reaction rates during the PS regeneration on FA-BC were remarkably improved by factors of 3.4 and 3.5 with increasing temperature from 20 °C to 50 °C. Both diffusion and desorption of MC-LR from FA-BC were thought to be the key factors for controlling the MC-LR oxidation rate during the PS regeneration of MC-LR. In addition, the decrease of pH (from 10 to 4) and increase of PS concentration (from 100 to 400 mg/L) enhanced the regeneration efficiency for MC-LR-spent FA-BC. The four cycles of adsorption-PS regeneration (200 mg/L PS, pH 6, and 50 °C) resulted in 92.81% regeneration efficiency in DI water and 82.89% in lake water. However, the four cycles of adsorption-PS regeneration led to the reduction of surface area (from 835 to 413 m2/g), oxidation of carbon surface and slight reduction of Fe0 on FA-BC. In overall, the cyclic adsorption-PS regeneration at higher temperature could provide practical reuse of FA-BC for cost-effective treatment of aqueous MC-LR.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Adsorção , Carvão Vegetal , Toxinas Marinhas , Microcistinas , Água , Poluentes Químicos da Água/análise
7.
Talanta ; 236: 122864, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34635246

RESUMO

Real time controllable assembling/aptasensing approach via plasmonic graphene oxide (GO) nanocomposites has been firstly proven to simultaneously give tuning of micro-nano structure of plasmonic GO and ultrasensitive detection of MC-LR toxin. In order to fabricate the assembly, a high-quality hollow triangular nanoplate AgClAu:p-GO (HTNP AgClAu:p-GO) can act as a template; furthermore, we combine DNA-hybridization with biotin-strepavidin binding protocol for tuning the HTNP AgClAu:p-GO assemblies from networks to laminar structure, and simultaneously loading Raman reporters into the assemblies. The dynamic assembling process can be utilized as a real time SERS aptasensor for detecting MC-LR due to ratiometric introduction of MC-LR toxin inhibiting formation of plasmonic p-GO assembly via toxin/aptamer bioconjugation and causing reverse alteration of SERS signal for giving ultrasensitive SERS detection of MC-LR. A detection limit of 6.3pM with a wide linear range from 10pM to 5 nM can be achieved. When the aptasensor has been applied in real samples, the real time assembling/aptasensing approach shows recoveries from 98% to 103% with relative standard deviation (RSD) lower than 3%, expecting that one-step nanofabrication and sensing strategy can be extended to in-field test of environmental contaminants.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Grafite , Limite de Detecção , Toxinas Marinhas , Microcistinas
8.
Talanta ; 236: 122880, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34635260

RESUMO

A novel aptamer-functionalized metal-organic framework nanofibrous composite (viz. PAN/UiO@UiO2-N3-aptamer) with a high aptamer coverage density was proposed based on the electrospinning and seeded growth method, and used for specific affinity recognition of trace Microcystin-LR (MC-LR). Heterobifunctional ligand was used to modify the metal-organic framework nanoparticles (MOF NPs) surface, which could passivate the MOF surface with respect to unmodified DNA, followed by coupling massive aptamers on MOF of the solid-phase microextraction (SPME) fiber using click chemistry. Characterizations including morphology, spectra analysis, mechanical stability, binding capacity and specificity were fulfilled. Applied to the analysis of MC-LR, the good selective and sensitive recognition were obtained with the detection limit as low as 0.003 ng/mL, which was better than most non-specific SPME or solid-phase extraction (SPE) protocols. The stability and reproducibility were acceptable, and the intra-day, inter-day and column-to-column relative standard deviations (RSDs) for the recovery of MC-LR were gained in the range from 2.5% to 14.3%, respectively. Satisfactory recoveries of MC-LR in environmental water samples were measured as 96.3 ± 4.7% - 98.9 ± 2.7% (n = 3) in tap water, 94.4 ± 2.5% - 96.1 ± 3.5% (n = 3) in pond water, and 97.0 ± 2.1% - 97.9 ± 3.1% (n = 3) in river water, respectively. This work demonstrated that the electrospun nanofibrous composite with massive aptamers would be a better alternative for ultra-trace MC-LR detection with good selectivity, matrix-resistance ability and high resolution.


Assuntos
Aptâmeros de Nucleotídeos , Estruturas Metalorgânicas , Nanofibras , Toxinas Marinhas , Microcistinas , Reprodutibilidade dos Testes
9.
Toxicon ; 204: 64-71, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34742780

RESUMO

In silico methodologies can be used in the discovery of new drugs for measuring toxicity, predicting effects of substances not yet analyzed by in vivo methodologies. The ADMET Predictor® software (absorption, distribution, metabolism, elimination, and toxicity [ADMET]) was used in this work to predict toxic effects of microcystin variants MC-LR, MC-YR, MC-RR, and MC-HarHar. In the case of rodents, predictive results for all analyzed variants indicated carcinogenic potential. The predictive model of respiratory sensitivity in this group differentiated microcystins into 2 categories: sensitizer (MC-LR and -YR) and non-sensitizer (MC-HarHar and -RR). Predictive results for humans indicated that MC-LR and -RR are phospholipidosis inducers; on the other hand, MC-LR showed the highest predictive value of permeability in rabbit cornea and probability of crossing lipoprotein barriers (MC-LR>-YR>-HarHar>-RR). Considering bioavailable fractions, microcystins are more likely to cause biological effects in rats than humans, showing significant differences between models. The results of ADMET predictions add valuable information on microcystin toxicity, especially in the case of variants not yet studied experimentally.


Assuntos
Cianobactérias , Microcistinas , Animais , Carcinógenos , Simulação por Computador , Microcistinas/toxicidade , Coelhos , Ratos
10.
Environ Sci Technol ; 55(22): 15196-15205, 2021 11 16.
Artigo em Inglês | MEDLINE | ID: mdl-34714625

RESUMO

To assess the risks associated with cyanobacterial blooms, the persistence and fate processes of cyanotoxins and other bioactive cyanobacterial metabolites need to be evaluated. Here, we investigated the reaction with photochemically produced singlet oxygen (1O2) for 30 cyanopeptides synthesized by Dolichospermum flos aquae, including 9 anabaenopeptins, 18 microcystins, 2 cyanopeptolins, and 1 cyclamide. All compounds were stable in UVA light alone but in the presence of a photosensitizer we observed compound-specific degradation. A strong pH effect on the decay was observed for 18 cyanopeptides that all contained tyrosine or structurally related moieties. We can attribute this effect to the reaction with 1O2 and triplet sensitizer that preferentially react with the deprotonated form of tyrosine moieties. The contribution of 1O2 to indirect phototransformation ranged from 12 to 39% and second-order rate constants for 9 tyrosine-containing cyanopeptides were assessed. Including the pH dependence of the reaction and system-independent second-order rate constants with 1O2 will improve the estimation of half-lives for multiclass cyanopeptide in surface waters. Our data further indicates that naturally occurring triplet sensitizers are likely to oxidize deprotonated tyrosine moieties of cyanopeptides and the specific reactivity and its pH dependence needs to be investigated in future studies.


Assuntos
Cianobactérias , Microcistinas , Concentração de Íons de Hidrogênio , Cinética , Oxigênio Singlete
11.
Rev Environ Contam Toxicol ; 258: 109-150, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34622370

RESUMO

Harmful cyanobacterial blooms are increasing and becoming a worldwide concern as many bloom-forming cyanobacterial species can produce toxic metabolites named cyanotoxins. These include microcystins, saxitoxins, anatoxins, nodularins, and cylindrospermopsins, which can adversely affect humans, animals, and the environment. Different methods to assess these classes of compounds in vitro and in vivo include biological, biochemical, molecular, and physicochemical techniques. Furthermore, toxic effects not attributable to known cyanotoxins can be observed when assessing bloom material. In order to determine exposures to cyanotoxins and to monitor compliance with drinking and bathing water guidelines, it is necessary to have reliable and effective methods for the analysis of these compounds. Many relatively simple low-cost methods can be employed to rapidly evaluate the potential hazard. The main objective of this mini-review is to describe the assessment of toxic cyanobacterial samples using in vitro and in vivo bioassays. Newly emerging cyanotoxins, the toxicity of analogs, or the interaction of cyanobacteria and cyanotoxins with other toxicants, among others, still requires bioassay assessment. This review focuses on some biological and biochemical assays (MTT assay, Immunohistochemistry, Micronucleus Assay, Artemia salina assay, Daphnia magna test, Radionuclide recovery, Neutral red cytotoxicity and Comet assay, Enzyme-Linked Immunosorbent Assay (ELISA), Annexin V-FITC assay and Protein Phosphatase Inhibition Assay (PPIA)) for the detection and measurement of cyanotoxins including microcystins, cylindrospermopsins, anatoxin-a, saxitoxins, and nodularins. Although most bioassay analyses often confirm the presence of cyanotoxins at low concentrations, such bioassays can be used to determine whether some strains or blooms of cyanobacteria may produce other, as yet unknown toxic metabolites. This review also aims to identify research needs and data gaps concerning the toxicity assessment of cyanobacteria.


Assuntos
Cianobactérias , Microcistinas , Animais , Humanos , Microcistinas/toxicidade , Saxitoxina , Uracila
12.
Analyst ; 146(22): 7005-7020, 2021 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-34679153

RESUMO

An anisotropic plasmonic sheet-core-satellite (PSCS) superstructure can be controlled via competitive binding between aptamer/MC-LR conjugation and aptamer-ssDNA hybridization. SERS nanotags can be incorporated into anisotropic plasmonic sheet-cores, e.g., pGO/nanorods, or pGO/hollow AgCl : Au nanoplates so as to fabricate an aptasensor for "ON-OFF" detection of MC-LR toxin. Preparing a PSCS superstructure and detection of toxin can be simultaneously completed so as to simplify the detection procedure of MC-LR toxin. Detection sensitivity of MC-LR toxin can be optimized by controlling aspect ratios or hollow interiors of plasmonic core nanoparticles. Herein, a limit of detection (0.635 pM) with a wide linear range from 1 pM to 10 nM can be obtained via optimized PSCS of pGO/nanorod/dotnanotags. When the aptasensor was tested in real samples, the PSCS shows excellent recoveries from 96.6% to 104.5% with relative standard deviation (RSD) lower than 2.89% in spiked reservoir samples. It can be predicted that a one-step facile nanofabrication/aptasensing approach would be extensively applied for rapid detection of some other environmental contaminants.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Limite de Detecção , Toxinas Marinhas , Microcistinas
13.
Ecotoxicol Environ Saf ; 227: 112919, 2021 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-34715501

RESUMO

Microcystin-LR (MC-LR) is an intracellular toxin with multi-organ toxicity and the testis is one of its important target organs. Although there is increasing research on MC-LR in male reproductive toxicity, the association between DNA damage and autophagy induced by MC-LR in male germ cells are still unclear. Therefore, it is important to explore the mechanism of MC-LR-induced DNA damage and the role of the activated ATM/p53 signaling pathway in testicular toxicity. The present study showed that MC-LR exposure significantly reduced gonadal index and induced pathological damage of the testes in mice. In addition, MC-LR increased the oxidative stress-related indicator hydroxyl radical, accompanied by increased levels of DNA damage-related indicators gamma-H2AX, 8-hydroxy-2'-deoxyguanosine, the olive tail moment (OTM) and DNA content of comet tail (TailDNA%) in trailing cells. Moreover, MC-LR activated the ATM/p53 pathway by enhancing the phosphorylation levels of ATM, CHK2 and p53 proteins, and then led to cell autophagy, ultimately triggering disrupted testicular cell arrangement, reduced sperm count and spermatogenic cell shedding. Importantly, after pretreatment with the antioxidant NAC, the expression levels of DNA damage-related indicators and the extent of damage in male germ cells were significantly reduced. Furthermore, pretreatment with the ATM inhibitor KU55933 could reduce the occurrence of autophagy and mitigate testicular toxicity of MC-LR through inhibiting the activation of the ATM/p53 pathway. These results indicate that MC-LR-induced oxidative stress can activate the DNA damage-mediated ATM/p53 signalling pathway to induce autophagy in male germ cells. This study provides a novel insight to further clarify the reproductive toxicity caused by MC-LR and to protect male reproductive health.


Assuntos
Apoptose , Proteína Supressora de Tumor p53 , Animais , Autofagia , Dano ao DNA , Células Germinativas/metabolismo , Masculino , Toxinas Marinhas , Camundongos , Microcistinas , Estresse Oxidativo , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo
14.
Ecotoxicol Environ Saf ; 227: 112925, 2021 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-34717216

RESUMO

Microcystin-LR (MC-LR) is one of the most worldwide harmful cyanobacterial toxins. A lots of antibodies against MC-LR have been generated and characterized. However, the knowledge about the epitopes of MC-LR was still limited. The objective of this study was to analyze the epitopes of MC-LR and demonstrate the binding mode of MC-LR with its antibody. The variable genes of a mouse hybridoma cell line (Mab5H1-3B3) raised against MC-LR have been cloned and assembled in a single chain variable fragment (scFv), and then soluble expressed in E.coli BL21. Based on the scFv, the IC50 and IC10 for MC-LR were determined to be 7.45 nM and 0.30 nM by competitive ELISA. And the scFv also showed 115% and 112% cross-reactivities to MC-RR and MC-YR, and 59% to MC-LA. By molecular docking, the binding mode between MC-LR and its scFv was demonstrated. A hydrogen bond interaction was observed between the carbonyl group of Adda5 residue of MC-LR and its scFv, and the guanidyl group of Arg4 residue and phenyl group of Adda5 residue of MC-LR were also involved in the interaction. These predicted epitopes were supported by antibody cross-reactivity data. By comparing the antibody informatics of MC-LR scFv with its predicted paratopes, VH-CDR1 was crucial for MC-LR binding, and its specificity could be tuned by engineering in Vκ-CDR1 and Vκ-CDR3. These information would be useful for the hapten design for microcystins or improving the properties of MC-LR scFv in vitro.


Assuntos
Microcistinas , Animais , Ensaio de Imunoadsorção Enzimática , Epitopos , Toxinas Marinhas , Camundongos , Simulação de Acoplamento Molecular
15.
Anal Chim Acta ; 1185: 339078, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34711309

RESUMO

An ultrasensitive photoelectrochemical (PEC) immunosensor based on gold nanoclusters (AuNCs) with 11-mercaptoundecanoic acid (MUA) ligands was fabricated for determination of microcystin-LR (MC-LR). The PEC immunosensor was developed by loading the monoclonal MC-LR antibody (Ab) to the MUA-AuNCs modified gold electrodes. After different measurement conditions being optimized, silver nanoparticles (AgNPs), gold nanorods (AuNRs), graphene oxide (GO) and carboxyl-functionalized graphene oxide (cGO) were introduced into MUA-AuNCs to enhance the sensing properties. The experimental result revealed that the sensitivity of PEC immunosensors was enhanced by both their photoelectrochemical properties and antibody loading properties with dependent relationship, which was different from the enhancement strategy of PEC sensors based on redox reactions. Among different hybrid nanocomposites, MUA-AuNCs/cGO not only improved the photoelectrochemical properties, but also loaded more antibodies for sensing, which resulted in best sensing performance. Thus, a universal method was proposed to enhance the sensing performance of PEC immunosensors based on impedance changes. Finally, MUA-AuNCs/cGO based PEC immunosensors exhibited a wide linear range of 0.001 nM-1000 nM with low detection limit of 0.011 pM (S/N = 3) for MC-LR determination. Meanwhile, the designed PEC immunosensors showed high selectivity, reproducibility and specificity, which provided the promising applications in aquatic environment.


Assuntos
Técnicas Biossensoriais , Grafite , Nanopartículas Metálicas , Técnicas Eletroquímicas , Ouro , Imunoensaio , Limite de Detecção , Toxinas Marinhas , Microcistinas , Reprodutibilidade dos Testes , Prata
16.
J Chromatogr A ; 1656: 462542, 2021 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-34543883

RESUMO

A novel aptamer@AuNPs@UiO-66-NH2 electrospun nanofibrous coating fiber for specific recognition of microcystin-LR (MC-LR) was proposed by using electrospinning, metal-organic frameworks (MOF) seed growth and AuNPs bridging aptamer strategies. Characterization of morphology, structure and stability of the obtained affinity nanofibrous coating fiber were investigated. High loading of MOFs and aptamers on the nanofibrous fiber were achieved and successfully applied for accurate identification of MC-LR by solid-phase microextraction (SPME) coupled with LC-MS. Highly specific recognition of MC-LR with little interference of analogs was achieved with extremely low LOD (0.004 ng/mL), good precision (CV% < 11.0%) and low relative error (RE% = -1.5% to -10.0%), which was rather better than that of the traditional SPME or SPE protocols. Satisfactory recoveries of MC-LR were obtained in the range of 92.0-96.8% (n = 3) in fortified tap water, raw pond water and river water samples. This work revealed an attractive alternative access to specific recognition and super-sensitive analysis of MC-LR in water.


Assuntos
Aptâmeros de Nucleotídeos , Nanopartículas Metálicas , Estruturas Metalorgânicas , Nanofibras , Ouro , Microcistinas , Água
17.
Water Res ; 204: 117620, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34492364

RESUMO

Cyanobacteria are a potential threat to aquatic ecosystems and human health because of their ability to produce cyanotoxins, such as microcystins (MCs). MCs are regularly monitored in fresh waters, but rarely in estuarine and marine waters despite the possibility of their downstream export. Over a period of two years, we monthly analyzed intracellular (in phytoplankton) and extracellular (dissolved in water) MCs at five stations along a river continuum from a freshwater reservoir with ongoing cyanobacterial blooms to the coast of Brittany, France. MCs were quantified using two integrative samplers placed at each site: solid phase adsorption toxin tracking (SPATT) samplers for collecting extracellular MCs and caged mussels (Anodonta anatina and Mytilus edulis) filter-feeding on MC-producing cyanobacteria. The MC transfer was demonstrated each year during five months at estuarine sites and sporadically at the marine outlet. SPATT samplers integrated extracellular MCs, notably at low environmental concentrations (0.2 µg/L) and with the same variant profile as in water. The mussel A. anatina highlighted the presence of MCs including at intracellular concentrations below 1 µg/L. M. edulis more efficiently revealed the MC transfer at estuarine sites than water samplings. Bivalves showed the same MC variant profile as phytoplankton samples, but with differential accumulation capacities between the variants and the two species. Using SPATT or bivalves can give a more accurate assessment of the contamination level of a freshwater-marine continuum, in which the MC transfer can be episodic. MC content in M. edulis represents a potent threat to human health if considering updated French guideline values, and particularly the total (free and protein-bound) MC content, highlighting the necessity to include cyanotoxins in the monitoring of seafood originating from estuarine areas.


Assuntos
Bivalves , Microcistinas , Animais , Ecossistema , Água Doce , Humanos , Água
18.
J Hazard Mater ; 416: 125729, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34492776

RESUMO

Metal sites (Ni, Bi or Ag) were introduced into carbon strengthened expanded graphite (CEG) based photocatalysts, and performed as a novel strategy to enhance the elimination of Microcystis aeruginosa and microcystin-LR from water. Results show that metal doping can efficiently improve the adsorption of harmful algae and enhance the photocatalytic activities in inactivation of harmful algae and degradation of MC-LR. Among the CEG catalysts, Ni-CEG can achieve the highest removal rate up to 90.6% for algal cells with 5 h visible light irradiation, while Bi-CEG catalyst provides the best performance for MC-LR degradation with the removal rate of 80.9% in 6 h visible light irradiation. In general, considering the coexistence of algal cells and microcystin-LR, Bi-CEG is proved to be an excellent candidate for the remediation of eutrophicated waters since it can achieve the efficient removal of both harmful algae and MC-LR. DFT calculations indicate that metal doping can transform the photocatalysts into n-type semiconductor, and provide the mid-gap state. In addition, the partial charge density distribution near Fermi level was mainly composed by the metal dopants, which can enhance the interaction with harmful algae and MC-LR.


Assuntos
Poluentes Ambientais , Grafite , Microcystis , Poluentes Químicos da Água , Carbono , Microcistinas , Água
19.
Int J Mol Sci ; 22(18)2021 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-34576099

RESUMO

We were the first to previously report that microcystin-LR (MC-LR) has limited effects within the colons of healthy mice but has toxic effects within colons of mice with pre-existing inflammatory bowel disease. In the current investigation, we aimed to elucidate the mechanism by which MC-LR exacerbates colitis and to identify effective therapeutic targets. Through our current investigation, we report that there is a significantly greater recruitment of macrophages into colonic tissue with pre-existing colitis in the presence of MC-LR than in the absence of MC-LR. This is seen quantitatively through IHC staining and the enumeration of F4/80-positive macrophages and through gene expression analysis for Cd68, Cd11b, and Cd163. Exposure of isolated macrophages to MC-LR was found to directly upregulate macrophage activation markers Tnf and Il1b. Through a high-throughput, unbiased kinase activity profiling strategy, MC-LR-induced phosphorylation events were compared with potential inhibitors, and doramapimod was found to effectively prevent MC-LR-induced inflammatory responses in macrophages.


Assuntos
Inflamação/patologia , Macrófagos/patologia , Toxinas Marinhas/toxicidade , Microcistinas/toxicidade , Animais , Biomarcadores/metabolismo , Colite/genética , Colite/patologia , Colo/efeitos dos fármacos , Colo/patologia , Sulfato de Dextrana , Modelos Animais de Doenças , Regulação da Expressão Gênica/efeitos dos fármacos , Inflamação/genética , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Naftalenos/farmacologia , Proteínas Quinases/metabolismo , Proteoma/metabolismo , Pirazóis/farmacologia , Ratos
20.
Water Environ Res ; 93(11): 2807-2818, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34520086

RESUMO

Frequent outbreaks of harmful algal blooms (HABs) have brought adverse impacts on human health, economic viability, and recreational activities in many communities in the United States. Cyanobacteria (or blue-green algae) blooms are the most common type of HABs in surface water. Current bactericides for controlling the blooms are disadvantageous due to the recycling difficulty. In this study, an innovative magnetic nanomaterial-γFe2 O3 /TiO2 nanoparticle-was used to inactivate toxic cyanobacteria species found in a lake in Southern Illinois that frequently experienced HABs. Cyanotoxin genes of mcy, nda, cyr, and sxt were used for targeting microcystin-, nodularin-, cylindrospermopsin-, and saxitoxin-producing cyanobacteria, respectively, by quantitative polymerase chain reaction (PCR) method. It was found that the concentration of chlorophyll a presents a strong correlation (R2 = 0.6024) with the gene copy obtained from 16S rRNA targeted for all cyanobacteria, but not with that from individual toxigenic cyanobacteria. The inactivation efficiencies of the nanomaterials under visible light were as high as 5-log and 1-log for cyanobacteria species containing mcyE/ndaF and sxtA genes, respectively, an improvement over the treatment under darkness. These nanomaterials can be recycled by their magnetic properties for reuse. Communities susceptible to HAB outbreaks are expected to benefit from the developed method for mitigating the blooms. PRACTITIONER POINTS: Lab-made γFe2 O3 /TiO2 nanoparticles can be used to inactivate microcystin/nodularin- and saxitoxin-producing cyanobacteria species. qPCR method can be used for targeting toxic cyanobacteria; Chl a cannot be used as a standalone indicator for HABs. Better inactivation efficiency under visible light indicated possible application of the technology under sunlight for HAB mitigation from surface water.


Assuntos
Cianobactérias , Nanopartículas , Antibacterianos , Clorofila A , Proliferação Nociva de Algas , Humanos , Lagos , Microcistinas , RNA Ribossômico 16S , Titânio
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