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1.
Part Fibre Toxicol ; 19(1): 26, 2022 Apr 07.
Artículo en Inglés | MEDLINE | ID: mdl-35392949

RESUMEN

BACKGROUND: Nanomaterials have been widely used in electrochemistry, sensors, medicine among others applications, causing its inevitable environmental exposure. A raising question is the "carrier" effect due to unique surface properties of nanomaterials, which may collectively impact the bioavailability, toxicokinetic, distribution and biological effects of classic toxicants. Noteworthy, this aspect of information remains largely unexplored. METHODS: Here, we deliberately selected two entities to mimic this scenario. One is graphene oxide (GO), which is made in ton quantity with huge surface-area that provides hydrophilicity and π-π interaction to certain chemicals of unique structures. The other is Microcystin-LR (MCLR), a representative double-bond rich liver-toxic endotoxin widely distributed in aquatic-system. Firstly, the adsorption of GO and MCLR after meeting under environmental conditions was explored, and then we focused on the toxicological effect and related mechanism of GO-MCLR complex on human skin cutin forming cells (HaCaT cells) and normal liver cells (L02 cells). RESULTS: Abiotically, our study demonstrated that GO could effectively adsorb MCLR through hydrogen bonding and π-π interaction, the oxidation degree of GO-MCLR decreased significantly and surface defect level raised. Compared to GO or MCLR, GO-MCLR was found to induce more remarkable apoptosis and ferroptosis in both HaCaT and L02 cells. The underlying mechanism was that GO-MCLR induced stronger intracellular reactive oxygen species (ROS) and mtROS generation, followed by Fe2+ accumulation, mitochondrial dysfunction and cytoskeletal damage. CONCLUSIONS: These results suggest that the GO-MCLR complex formed by GO adsorption of MCLR may exhibit more toxic effects than the single material, which demonstrates the necessity for assessing nano-toxicant complexity. Our discovery may serve as a new toxicological paradigm in which nanomaterial mediated surface adsorption effects could impact the degree of cytotoxicity and toxicological mechanisms of classic toxins.


Asunto(s)
Grafito , Microcistinas , Grafito/toxicidad , Humanos , Toxinas Marinas/toxicidad , Microcistinas/química , Microcistinas/toxicidad
2.
Ecotoxicol Environ Saf ; 236: 113454, 2022 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-35367887

RESUMEN

Microcystin-leucine arginine (MC-LR), an emerging water pollutant, produced by cyanobacteria, has an acute testicular toxicity. However, little is known about the chronic toxic effects of MC-LR exposure on the testis at environmental concentrations and the underlying molecular mechanisms. In this study, C57BL/6 J mice were exposed to different low concentrations of MC-LR for 6, 9 and 12 months. The results showed that MC-LR could cause testis structure loss, cell abscission and blood-testis barrier (BTB) damage. Long-term exposure of MC-LR also activated RhoA/ROCK pathway, which was accompanied by the rearrangement of α-Tubulin. Furthermore, MC-LR reduced the levels of the adherens junction proteins (N-cadherin and ß-catenin) and the tight junction proteins (ZO-1 and Occludin) in a dose- and time-dependent way, causing BTB damage. MC-LR also reduced the expressions of Occludin, ZO-1, ß-catenin, and N-cadherin in TM4 cells, accompanied by a disruption of cytoskeletal proteins. More importantly, the RhoA inhibitor Rhosin ameliorated these MC-LR-induced changes. Together, these new findings suggest that long-term exposure to MC-LR induces BTB damage through RhoA/ROCK activation: involvement of tight junction and adherens junction changes and cytoskeleton disruption. This study highlights a new mechanism for MC-LR-induced BTB disruption and provides new insights into the cause and treatment of BTB disruption.


Asunto(s)
Barrera Hematotesticular , beta Catenina , Animales , Cadherinas , Masculino , Ratones , Ratones Endogámicos C57BL , Microcistinas/toxicidad , Ocludina/metabolismo
3.
Ecotoxicol Environ Saf ; 236: 113439, 2022 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-35367891

RESUMEN

Global warming is favouring the incidence, intensity and duration of harmful cyanobacterial blooms. Microcystin-LR (MC-LR), a hepatotoxic agent, is produced during cyanobacterial blooms. To understand the molecular mechanisms of acute hepatotoxic effect of low doses of MC-LR in crab, we examined differentially expressed genes in samples of the hepatopancreas of Chinese mitten crab (Eriocheir sinensis) collected in 48 h after injections of MC-LR at doses of 0, 25, 50, and 75 µg/kg. The results revealed that MC-LR induced changes in corresponding gene led to the accumulation of triglycerides. MC-LR exposure affected sterol metabolism. Apoptosis-related genes such as Fas-L, Bcl-XL, Cytc, AiF, p53, PERK, calpain, CASP2, CASP7, α-tubulin, PARP, GF, G12, and PKC were upregulated. Conversely, expression levels of CASP10 and ASK1 were downregulated. Genes related to the regulation of actin cytoskeleton (Rho, ROCK, MLCP, MLC, PAK, and PFN) were upregulated. Further, expression levels of genes encoding fatty acid elongation-related enzymes were upregulated, but the expression of genes related to fatty acid synthesis was slightly down regulated. Taken together, these results demonstrated the hepatic toxicity and molecular mechanisms of changes in lipid metabolism, immune and apoptosis in Chinese mitten crab under the MC-LR-induced stress, which is the first report on crabs and performs a comprehensive analysis and a new insight of the molecular toxicological responses in crabs.


Asunto(s)
Hepatopáncreas , Transcriptoma , Animales , Apoptosis , China , Ácidos Grasos/farmacología , Metabolismo de los Lípidos , Toxinas Marinas , Microcistinas/toxicidad
4.
Toxins (Basel) ; 14(4)2022 Apr 08.
Artículo en Inglés | MEDLINE | ID: mdl-35448873

RESUMEN

Toxic cyanobacteria in freshwater bodies constitute a major threat to public health and aquatic ecosystems [...].


Asunto(s)
Cianobacterias , Microcistinas , Ecosistema , Agua Dulce/microbiología , Microcistinas/toxicidad
5.
Toxicon ; 210: 148-154, 2022 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-35248587

RESUMEN

Microcystin-LR (MC-LR) is an environmental toxin that is synthesized by cyanobacteria and considered a potential human carcinogen. However, the role of MC-LR in prostate cancer progression has not been elucidated. The purpose of this study was to investigate the effect of MC-LR on prostate cancer cell invasion and its underlying mechanisms. Transwell assay was performed, and the result showed that MC-LR increased DU145 cell invasion in a concentration-dependent manner. The result of Western blot showed that MC-LR promoted ERK phosphorylation, while enhancing VASP and ezrin phosphorylation. Moreover, PD0325901 was used to verify the role of the ERK/VASP/ezrin axis in MC-LR-promoted cell invasion. The results revealed that MC-LR promoted microfilament rearrangement and cell invasion by activating the ERK/VASP/ezrin pathway in DU145 cells. Finally, in vivo assay was performed, and the result suggested that MC-LR promoted p-ERK, p-VASP and p-ezrin expression and local invasion in nude mice model. Taken together, our data proved that MC-LR induced microfilament rearrangement and cell invasion by activating the ERK/VASP/ezrin pathway in DU145 cells.


Asunto(s)
Citoesqueleto de Actina , Microcistinas , Animales , Proteínas del Citoesqueleto , Masculino , Toxinas Marinas , Ratones , Ratones Desnudos , Microcistinas/toxicidad
6.
Aquat Toxicol ; 245: 106127, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35248895

RESUMEN

Computational molecular modelling, mass spectrometry and in-vivo tests with Chlorella vulgaris (C. vulgaris) and Daphnia magna (D. magna) were used to investigate the liposolubility and ecotoxicity of MC-LR degradation by-products generated after oxidation by OH• radicals in Fenton process. Exposure of MC-LR (5 µg.L-1) to the most severe oxidation conditions (Fe2+ 20 mM and H2O2 60 mM) resulted in a reduction in the toxin concentration of 96% (0.16 µg.L-1), however, with the formation of many by-products. The by-product of m/z 445 was the most resistant to degradation and retained a toxic structure of diene bonds present in the Adda amino acid. Computational modeling revealed that m/z 445 (tPSA = 132.88 Ų; KOW = 2.02) is more fat-soluble than MC-LR (tPSA = 340.64 Ų; KOW = 0.68), evidencing an easier transport process of this by-product. Given this, toxicity tests using C. vulgaris and D. magna indicated greater toxicity of the by-product m/z 445 compared to MC-LR. When the conversion of MC-LR to by-products was 77%, the growth inhibition of C. vulgaris and the D. magna immobility were, respectively, 6.14 and 0%, with 96% conversion; growth inhibition and the immobility were both 100%  for both species.


Asunto(s)
Chlorella vulgaris , Contaminantes Químicos del Agua , Animales , Simulación por Computador , Daphnia/metabolismo , Peróxido de Hidrógeno/metabolismo , Toxinas Marinas/toxicidad , Microcistinas/toxicidad , Contaminantes Químicos del Agua/toxicidad
7.
Toxicon ; 211: 21-35, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-35288171

RESUMEN

The invasive nature of cyanotoxin-producing cyanobacteria and the adverse effects concerning their toxic impacts have gained heightened scientific attention of late. The persistence of cyanotoxins in irrigation water leads to bioaccumulation in plants, the development of phytotoxic effects, and the threat of groundwater contamination. The accumulation of cyanotoxins in plants is caused by several factors leading to severe toxic effects, including reduced plant growth and seed germination, enhanced oxidative stress, lowered rate of mineral uptake, decreased photosynthetic efficiency, and loss of chlorophyll content. The uptake and accumulation of cyanotoxins in plants can be concentration-dependent, as reported in a myriad of studies. Even though several studies have reported phytotoxic effects of cyanotoxin contamination, field-related studies reporting phytotoxic effects are particularly inadequate. Paradoxically, at realistic conditions, some plants are reported to be tolerant of cyanotoxins. Furthermore, the breadth of adverse impacts of cyanotoxins on human health is significant. Cyanotoxins cause major health effects including cancer, oxidative stress, organelle dysfunction, DNA damage, and enzyme inhibition. This review intends to present compelling arguments on microcystins (MCs), cylindrospermopsins (CYN), ß-N-methylamino-L-alanine (BMAA), and anatoxin-a (ANTX-a), their uptake and accumulation in crop plants, phytotoxic effects on plants, and potential health implications to humans. The accumulation of cyanotoxins implants cultivated as food crops, resulting in phytotoxic effects and adverse impacts on human health are serious issues that require scientific inputs to be addressed.


Asunto(s)
Cianobacterias , Clorofila , Humanos , Microcistinas/toxicidad
8.
Toxicon ; 210: 49-57, 2022 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-35217023

RESUMEN

With the continued influx and accumulation of polycyclic aromatic hydrocarbons (PAHs) in eutrophic waters, the effects of PAHs on cyanobacteria bloom need to be clarified. PAHs usually existed as mixtures in aquatic environments, but the combined toxicity of PAH mixtures to toxigenic cyanobacteria remained unknown. This study investigated the effects of phenanthrene (Phe) and benzo [a]pyrene (BaP), alone or in combination, on the growth and physiology of Microcystis aeruginosa. The results showed that a hormesis effect on growth at low doses of the single Phe (≤1 mg/L) or PAH mixtures (≤0.279 mg/L) was observed, whereas the single BaP induced significant growth inhibitions at all concentrations (≥0.2 mg/L). The median effective concentrations (96 h) for Phe, BaP and their mixtures were 4.29, 1.29 and 1.07 mg/L, respectively. Mixture toxicity models showed that Phe and BaP elicited a synergistic interaction on M. aeruginosa. The synergy may be ascribed to the excessive oxidative stress induced by PAH mixtures, which further led to membrane structure damages, photosynthesis inhibitions and decreased metabolic activity. Moreover, the microcystins (MCs) release significantly increased by 25.3% and 31.9% upon exposure to 0.558 and 1.116 mg/L of PAH mixtures. In all, this study suggested that the enhanced release of MCs by PAH mixtures might exacerbate potential risks to the aquatic environment.


Asunto(s)
Microcystis , Hidrocarburos Policíclicos Aromáticos , Microcistinas/metabolismo , Microcistinas/toxicidad , Estrés Oxidativo , Hidrocarburos Policíclicos Aromáticos/metabolismo , Hidrocarburos Policíclicos Aromáticos/toxicidad
9.
Aquat Toxicol ; 245: 106119, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35220087

RESUMEN

Cyanobacterial blooms impose a substantial risk for submerged macrophytes in aquatic environments. This study investigated the cellular and transcriptomic responses of Vallisneria natans to microcystin-LR (MCLR) exposure, as well as abscisic acid (ABA) and strigolactone (SL), which are the major compounds in signaling networks that regulate plant defense. The results revealed that MCLR significantly (p <0.05) decreased the photosynthetic pigments and significantly (p < 0.05) increased the contents of the ABA and SL stress-related phytohormones under MCLR stress. Related genes involved in the photosynthetic pathways were down-regulated, including psbO, psbP, psbQ and psbR. In the SL biosynthetic pathway of roots under MCLR stress, related genes, such as D27 and CCD7, were down-regulated, while the CCD8 and MAX1 genes were up-regulated. In the ABA synthetic pathway, the genes LUT5, ZEP, NCED, ABA2 and AAO3 were up-regulated. Furthermore, a reduction in the content of SL enriched ABA after 3 days under MCLR stress. The potential molecular mechanism of the interactions between SL and ABA were confirmed with the relative up- and down-regulated genes in the pathway, and ABA could play a major role in plant physiology under MCLR stress. This study provides valuable information to understand the stress-related mechanisms of response of submerged macrophytes to cyanobacterial blooms.


Asunto(s)
Reguladores del Crecimiento de las Plantas , Contaminantes Químicos del Agua , Toxinas Marinas , Microcistinas/metabolismo , Microcistinas/toxicidad , Reguladores del Crecimiento de las Plantas/metabolismo , Transcriptoma , Contaminantes Químicos del Agua/toxicidad
10.
Toxicon ; 210: 78-88, 2022 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-35150660

RESUMEN

Microcystin-LR (MC-LR) has been identified to pose an increasing threat to the male reproductive system in vivo and in vitro studies with the objects like mammal animals, amphibians, aquatic organisms, etc. This review demonstrates the latest research advances of the male reproductive toxicity induced by MC-LR in detail, which mainly consists of two aspects, namely pathological injuries to testis and prostate, as well as the endocrine disruption. Apart from the direct toxicity to the male reproductive system, we also underline the transgenerational reproductive toxicity that prenatal exposure may pass on to male offspring. This review also demonstrates the interactive effects between MC-LR and other compounds, including synergistic effects with some toxicants and antagonistic effects with some medicine or chemical modification. In terms of the mechanisms of MC-LR-induced toxicity, we mainly focus on the epigenetic modification and non-coding RNAs (ncRNAs)-related mechanisms which have provided a new perspective.


Asunto(s)
Arginina , Microcistinas , Animales , Arginina/toxicidad , Leucina/toxicidad , Masculino , Mamíferos , Toxinas Marinas/toxicidad , Microcistinas/toxicidad
11.
Sci Total Environ ; 823: 153624, 2022 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-35124034

RESUMEN

Microcystins (MCs) are the most widely distributed cyanobacterial toxins that can exert adverse effects on aquatic organisms, but aside from the study of the harmful effect of cyanobacterial blooms, little is known about the effect of released MCs on the growth and development of chironomid larvae. To assess the harmful effect and the toxic mechanism of MCs on midges, the life-history traits, intestinal microbiota, and transcriptome of Chironomus pallidivittatus were analyzed after chronic exposure to 30 µg/L of MC-LR. Exposure inhibited larvae body length by 35.61% and wet weight by 21.92%, increased emergence time of midges, damaged mitochondria in the intestine, promoted oxidative stress, dysregulated lipid metabolism of chironomid larvae, and increased detoxification enzymes glutathione S-transferase (GST) and superoxide dismutase (SOD) by 32.44% and 17.41%, respectively. Exposure also altered the diversity and abundance of the intestinal microbiota, favoring pathogenic and MC degradation bacteria. RNA sequencing identified 261 differentially expressed genes under MC-LR stress, suggesting that impairment of the peroxisome proliferator-activated receptor signaling pathway upregulated fatty acid biosynthesis and elongation to promote lipid accumulation. In addition, exposure-induced detoxification and antioxidant responses, indicating that the chironomid larvae had the potential ability to resist MC-LR. To our knowledge, this is the first time that lipid accumulation, oxidative stress, and detoxification have been studied in this organism at the environmentally relevant concentration of MC-LR; the information may assist in ecological risk assessment of cyanobacterial toxins and their effects on benthic organisms.


Asunto(s)
Chironomidae , Microbioma Gastrointestinal , Animales , Toxinas Marinas , Microcistinas/toxicidad , Estrés Oxidativo , Transcriptoma
12.
Toxicol Lett ; 358: 6-16, 2022 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-35032610

RESUMEN

Early experimental studies have demonstrated that microcystin-leucine arginine (MC-LR) is able to induce multiple organ damage. Female reproductive disorders caused by MC-LR have attracted increased attention in recent years. However, the underlying mechanisms of female reproductive malfunctions are not yet fully understood. Our previous study confirmed that MC-LR could enter mice ovary, induce apoptosis of ovarian granulosa cell and lead to follicular atresia. Research shows that ovary inflammation is positively related to the decline of female reproductive function. This study was aimed to find out the relationship between inflammation response and ovarian injury caused by MC-LR. MC-LR were administrated at 0, 7.5, 22.5 and 45 µg/kg for two weeks by intraperitoneal injection in female BALB/c mice. Histopathological analysis of ovary was performed. We found that MC-LR exposure induced inflammation response and fibrosis in ovary. In the present study, we observed that MC-LR could enter ovary and was mainly distributed in mGCs (mouse ovarian granulosa cells), but not in the theca-interstitial cells. We isolated and cultured mGCs with different concentrations of MC-LR at 0, 0.01, 0.1, 1 and 10 µM. MC-LR exposure caused mitochondrial DNA (mtDNA) leakage which was detected by qPCR andimmunofluorescence staining. Subsequently, mtDNA leakage activated cGAS-STING signaling, leading to elevated production of inflammatory cytokines TNF-α in mGCs.Diffusion of TNF-α in ovary resulted in inflammatory cell infiltration and interstitial cell proliferation. Ovarian inflammation provides a new perspective to explore the underlying mechanisms associated with MC-LR-induced female reproductive dysfunction.


Asunto(s)
Arginina , Microcistinas , Animales , Citocinas , ADN Mitocondrial , Femenino , Atresia Folicular , Células de la Granulosa , Inflamación/inducido químicamente , Leucina , Toxinas Marinas , Ratones , Ratones Endogámicos BALB C , Microcistinas/toxicidad , Nucleotidiltransferasas , Factor de Necrosis Tumoral alfa
13.
Artículo en Inglés | MEDLINE | ID: mdl-34826614

RESUMEN

With the intensification of water eutrophication around the world, cyanobacterial blooms have been becoming a common environmental pollution problem. The levels of microcystin-LR (MC-LR) and nitrite rise sharply during the cyanobacterial bloom period, which may have potential joint toxicity on aquatic organisms. In this study, adult male zebrafish were immersed into different joint solutions of MC-LR (0, 3, 30 µg/L) and nitrite (0, 2, 20 mg/L) for 30 days to explore the neurotoxic effects and underlying mechanisms. The results showed that single factor MC-LR or nitrite caused a concentration-dependent damage in brain ultrastructure and the effects of their joint exposure were much more intense. Downregulated expression of mbp and bdnf associated with myelination of nerve fibers further confirmed that MC-LR and nitrite could damage the structure and function of neuron. The decreases in dopamine content, acetylcholinesterase activity and related gene mRNA levels indicated that MC-LR and nitrite adversely affected the normal function of the dopaminergic and cholinergic systems in zebrafish brain. In addition, the significant increase in malondialdehyde content suggested the occurrence of oxidative stress caused by MC-LR, nitrite and their joint-exposure, which paralleled a significant decrease in antioxidant enzyme­manganese superoxide dismutase activity and its transcription level. In conclusion, MC-LR + Nitrite joint-exposure has synergistic neurotoxic effects on the structure and neurotransmitter systems of fish brain, and antioxidant capacity disruption caused by these two factors might be one of the underlying synergistic mechanisms. Therefore, there is a risk of being induced neurotoxicity in fish during sustained cyanobacterial bloom events.


Asunto(s)
Toxinas Marinas/toxicidad , Microcistinas/toxicidad , Síndromes de Neurotoxicidad/etiología , Neurotransmisores/metabolismo , Nitritos/toxicidad , Pez Cebra/fisiología , Acetilcolinesterasa/metabolismo , Animales , Antioxidantes/metabolismo , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Encéfalo/fisiología , Dopamina , Sinergismo Farmacológico , Ecotoxicología , Masculino , Síndromes de Neurotoxicidad/metabolismo , Oxidantes/metabolismo , Estrés Oxidativo/efectos de los fármacos , Contaminantes Químicos del Agua/toxicidad , Proteínas de Pez Cebra/genética
14.
Sci Total Environ ; 810: 152104, 2022 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-34863769

RESUMEN

Global warming and eutrophication may lead to increased incidence of harmful algal blooms and related production of cyanotoxins that can be toxic to aquatic plants. Previous studies have evaluated the phytotoxic effects of cyanotoxins on aquatic plants. However, most studies have evaluated only a limited number of plant species and cyanotoxins; there is also considerable variability between studies, which obscures general patterns and hinders understanding of the phytotoxic effects of cyanotoxins. Here, we conducted a comprehensive meta-analysis by compiling 41 published papers to estimate the phytotoxic effects of anatoxin-a, cylindrospermopsin, and microcystins in 34 species of aquatic plants, with the aim of 1) investigating the phytotoxicity of different cyanotoxins to aquatic plants; 2) determining the aquatic plant species most sensitive to the phytotoxic effects of cyanotoxins; and 3) evaluating the bioaccumulation potential of cyanotoxins in aquatic plants. Most aquatic plants were negatively affected by cyanotoxin exposure and their response was dose-dependent; however, morphological indicators and photosynthesis of certain aquatic plants were marginally stimulated under low concentrations of anatoxin-a and cylindrospermopsin. Anatoxin-a showed the greatest bioaccumulation capacity in aquatic plants compared to cylindrospermopsin and microcystin variants. Bioaccumulation factors of cyanotoxins in aquatic plants generally decreased with increasing water exposure concentrations. Our study supports the One Health goal to manage the risk of public exposure to toxic substances, and indicates that cyanotoxins warrant further investigations in aquatic plants. Environmental managers and public health authorities need to be alert to the long-term exposure and chronic toxicity of cyanotoxins, and the potential trophic transfer of cyanotoxins from aquatic plants to higher-order organisms.


Asunto(s)
Toxinas Bacterianas , Microcistinas , Alcaloides , Floraciones de Algas Nocivas , Microcistinas/toxicidad , Tropanos
15.
Toxicology ; 465: 153058, 2022 01 15.
Artículo en Inglés | MEDLINE | ID: mdl-34863901

RESUMEN

Few studies exist on the toxic effects of chronic exposure to microcystins (MCs) on amphibian intestines, and the toxicity mechanisms are unclear. Here, we evaluated the impact of subchronic exposure (30 days) to environmentally realistic microcystin-leucine arginine (MC-LR) concentrations (0 µg/L, 0.5 µg/L and 2 µg/L) on tadpole (Lithobates catesbeianus) intestines by analyzing the histopathological and subcellular microstructural damage, the antioxidative and oxidative enzyme activities, and the transcriptome levels. Histopathological results showed severe damage accompanied by inflammation to the intestinal tissues as the MC-LR exposure concentration increased from 0.5 µg/L to 2 µg/L. RNA-sequencing analysis identified 634 and 1,147 differentially expressed genes (DEGs) after exposure to 0.5 µg/L and 2 µg/L MC-LR, respectively, compared with those of the control group (0 µg/L). Biosynthesis of unsaturated fatty acids and the peroxisome proliferator-activated receptor (PPAR) signaling pathway were upregulated in the intestinal tissues of the exposed groups, with many lipid droplets being observed on transmission electron microscopy, implying that MC-LR may induce lipid accumulation in frog intestines. Moreover, 2 µg/L of MC-LR exposure inhibited the xenobiotic and toxicant biodegradation related to detoxification, implying that the tadpoles' intestinal detoxification ability was weakened after exposure to 2 µg/L MC-LR, which may aggravate intestinal toxicity. Lipid accumulation and toxin efflux disorder may be caused by MC-LR-induced endoplasmic reticular stress. This study presents new evidence that MC-LR harms amphibians by impairing intestinal lipid metabolism and toxin efflux, providing a theoretical basis for evaluating the health risks of MC-LR to amphibians.


Asunto(s)
Absorción Intestinal/efectos de los fármacos , Intestinos/efectos de los fármacos , Metabolismo de los Lípidos/efectos de los fármacos , Toxinas Marinas/toxicidad , Microcistinas/toxicidad , Rana catesbeiana/metabolismo , Animales , Retículo Endoplásmico/efectos de los fármacos , Retículo Endoplásmico/metabolismo , Estrés del Retículo Endoplásmico/efectos de los fármacos , Intestinos/enzimología , Intestinos/metabolismo , Larva/efectos de los fármacos , Larva/genética , Larva/metabolismo , Mitocondrias/efectos de los fármacos , Mitocondrias/metabolismo , Transportadores de Anión Orgánico/genética , Transportadores de Anión Orgánico/metabolismo , Estrés Oxidativo/efectos de los fármacos , Rana catesbeiana/embriología , Rana catesbeiana/genética , Especies Reactivas de Oxígeno/metabolismo , Transcriptoma/efectos de los fármacos
16.
Ecotoxicol Environ Saf ; 229: 113054, 2022 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-34894426

RESUMEN

Microcystin-LR (MC-LR), mainly released by Microcystis aeruginosa, is posing a tremendous risk to aquatic animals and human health. Meanwhile, biochar (BC) is gradually be used as a sustainable adsorbent to immobilize and remove water pollutants. In our study, we for the first time conducted a full-scale investigation on lipid metabolism and its regulation mechanism of female zebrafish (Danio rerio) exposed to 0, 10 µg/L MC-LR, 100 µg/L BC, and 10 µg/L MC-LR+ 100 µg/L BC. The results indicated that sub-chronic MC-LR exposure induced hepatic lipidosis and apoptosis, including the formation of lipid droplets, significantly elevation of hepatic triglyceride (TG) level as well as significant upregulated expression of lipogenesis-related genes (foxo1a, elovl5, pparγ) and pro-apoptotic genes (bax, casp3). Nevertheless, no significant alteration was observed in the single BC group and the combined exposure group, which indicated that BC may solely functioned as an absorbent agent to lower MC-LR bioaccumulation in zebrafish liver and alleviate MC-LR-induced hepatotoxicity. Our findings revealed that the utilization of rice straw-derived BC can adsorb and immobile MC-LR in the water, subsequently alleviated the MC-LR-induced hepatic lipidosis and apoptosis in female zebrafish. On the basis of fish health, it is urgent to explore the feasibility of using environmentally friendly materials like BC to adsorb pollutants in water.


Asunto(s)
Lipidosis , Oryza , Contaminantes Químicos del Agua , Acetiltransferasas , Animales , Apoptosis , Carbón Orgánico , Femenino , Toxinas Marinas , Microcistinas/toxicidad , Contaminantes Químicos del Agua/toxicidad , Pez Cebra , Proteínas de Pez Cebra
17.
Sci Total Environ ; 818: 151749, 2022 Apr 20.
Artículo en Inglés | MEDLINE | ID: mdl-34843796

RESUMEN

The accumulation of diminutive plastic waste in the environment, including microplastics and nanoplastics, has threatened the health of multiple species. Nanoplastics can adsorb the pollutants from the immediate environment, and may be used as carriers for pollutants to enter organisms and bring serious ecological risk. To evaluate the toxic effects of microcystin-LR (MCLR) on the liver of adult zebrafish (Danio rerio) in the presence of 70 nm polystyrene nanoplastics (PSNPs), zebrafish were exposed to MCLR alone (0, 0.9, 4.5 and 22.5 µg/L) and a mixture of MCLR + PSNPs (100 µg/L) for three months. The results indicated that groups with combined exposure to MCLR and PSNPs further enhanced the accumulation of MCLR in the liver when compared to groups only exposed to MCLR. Cellular swelling, fat vacuolation, and cytoarchitectonic damage were observed in zebrafish livers after exposure to MCLR, and the presence of PSNPs exacerbated these adverse effects. The results of biochemical tests showed the combined effect of MCLR + PSNPs enhanced MCLR-induced hepatotoxicity, which could be attributed to the altered levels of reactive oxygen species, malondialdehyde and glutathione, and activities of catalase. The expression of genes related to antioxidant responses (p38a, p38b, ERK2, ERK3, Nrf2, HO-1, cat1, sod1, gax, JINK1, and gstr1) was further performed to study the mechanisms of MCLR combined with PSNPs aggravated oxidative stress of zebrafish. The results showed that PSNPs could improve the bioavailability of MCLR in the zebrafish liver by acting as a carrier and accelerate MCLR-induced oxidative stress by regulating the levels of corresponding enzymes and genes.


Asunto(s)
Contaminantes Químicos del Agua , Pez Cebra , Animales , Hígado/metabolismo , Toxinas Marinas , Microcistinas/metabolismo , Microcistinas/toxicidad , Microplásticos/toxicidad , Estrés Oxidativo , Plásticos/metabolismo , Poliestirenos/metabolismo , Poliestirenos/toxicidad , Contaminantes Químicos del Agua/metabolismo , Contaminantes Químicos del Agua/toxicidad , Pez Cebra/metabolismo
18.
Environ Sci Pollut Res Int ; 29(16): 23194-23205, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-34799801

RESUMEN

Cyanobacterial blooms are increasingly common in aquatic environments worldwide. These microorganisms cause concern due to their ability to produce cyanotoxins. Aquatic organisms, especially zooplankton, are exposed to cyanobacterial toxins by different routes, depending on the bloom phase. During cyanobacterial dominance, zooplankton is exposed to cyanotoxins through the ingestion of cyanobacterial cells, while at the bloom senescence, dissolved toxins are the most representative route. In this study, we assessed the effects of a microcystin-producing strain of Microcystis aeruginosa (NPLJ-4) on clones of the tropical small cladocerans Macrothrix spinosa (two clones) and Ceriodaphnia cornuta (one clone) exposed to intact cells and aqueous cell crude extracts. Short-term toxicity assays and life-table experiments were performed to assess the effects of the toxic M. aeruginosa on the survival and life history of the cladocerans. In the short-term toxicity assay, we found that cladocerans were more affected by intact cells. Both clones of M. spinosa were more affected when exposed to intact cells, while C. cornuta displayed about 5-fold more resistance. On the other hand, crude extracts had a low impact on cladocerans' survival. Also, we observed a significant decrease in survival, fecundity, and growth of animals exposed to sublethal and environmentally relevant concentrations of M. aeruginosa cellular biomass. However, even at high concentrations of dissolved microcystins, the crude extract did not have significant effects on the life history parameters of the cladocerans. Although they can be found during cyanobacterial bloom events, small-bodied cladocerans are still affected by toxic Cyanobacteria depending on the exposure route.


Asunto(s)
Cladóceros , Cianobacterias , Microcystis , Animales , Extractos Celulares , Ingestión de Alimentos , Microcistinas/toxicidad
19.
Environ Sci Pollut Res Int ; 29(8): 11320-11331, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-34533748

RESUMEN

Microcystis aeruginosa produces an abundant cyanotoxin (microcystins (MCs) in freshwater supplies. MCs have adverse health hazards to animals and humans. Microcystin-leucine-arginine (microcystin-LR or MC-LR) is the most studied among these MCs due to their high toxicity. So, this study was designed to evaluate the possible therapeutic role of the natural algal food supplement, Spirulina platensis (SP), against MC-LR-induced toxic effects in male Wistar rats. Forty rats were randomly divided into five groups. Control and SP groups orally administered distilled water and SP (1000 mg/kg/daily), respectively, for 21 days. MC-LR group was intraperitoneally injected with MC-LR (10 µg/kg/day) for 14 days. MC-LR-SP500 and MC-LR-SP1000 groups were orally treated with SP (500 and 1000 mg/kg, respectively) for 7 days and concomitantly with MC-LR for 14 days. MC-LR induced oxidative hepatorenal damage, cardiotoxicity, and neurotoxicity greatly, which was represented by reduction of reduced glutathione content and the activities of glutathione peroxidase, catalase, and superoxide dismutase and elevation of concentrations of nitric oxide and malondialdehyde in renal, hepatic, brain, and heart tissues. In addition, it increased serum levels of urea, creatinine, tumor necrosis factor-alfa, interleukin-1beta and interleukin-6 and serum activities of alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, creatine kinase, and creatine kinase-MB. However, S. platensis restored normal levels of measured serum parameters, ameliorated MC-LR-induced oxidative damage, and normalized tissue antioxidant biomarkers. In conclusion, SP alleviated MC-induced organ toxicities by mitigating oxidative and nitrosative stress and lipid peroxidation.


Asunto(s)
Toxinas Marinas , Microcistinas , Animales , Antioxidantes/metabolismo , Glutatión/metabolismo , Hígado/metabolismo , Masculino , Microcistinas/metabolismo , Microcistinas/toxicidad , Estrés Oxidativo , Ratas , Ratas Wistar , Spirulina
20.
Toxicon ; 206: 74-84, 2022 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-34942216

RESUMEN

Anabaenopeptins and microcystins are oligopeptides produced by bloom-forming cyanobacteria. We determined in vivo effects of anabaenopeptin-B (AN-B) and two variants of microcystins of different hydrophobicity (MC-LR and MC-LF) on the physiology of Daphnia magna. Heart rate, thoracic limb activity and post-abdominal claw activity were determined by digital video analysis and oxygen consumption by Oxygraph + system. EC50 calculation and isobole methodology for interactive effects of AN-B and MC-LR mixture were used. Daphnids' responses to all three oligopeptides were concentration- and time-dependent. MC-LF was the most potent inhibitor of heart rate, thoracic limb activity, post-abdominal claw activity and oxygen consumption. AN-B was more toxic than MC-LR toward oxygen consumption; it inhibited the movements of limbs and post-abdominal claw similarly to MC-LR, but did not inhibit heart rate. The strongest toxic effects were induced by the binary mixture of AN-B with MC-LR at the sum concentration equal to the concentration of the single compounds. First time direct synergistic toxic effects of the cyanopeptides on all the physiological parameters were found. The obtained results explain stronger disturbances in aquatic organisms caused by cyanobacterial cell contents than the individual cyanopeptides present even at higher concentrations. Other metabolites and their interactions need further studies.


Asunto(s)
Cianobacterias , Daphnia , Animales , Organismos Acuáticos , Microcistinas/toxicidad , Oligopéptidos/toxicidad
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