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1.
J Agric Food Chem ; 68(7): 1966-1973, 2020 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-31986037

RESUMO

Pesticide pollution of surface water represents a considerable risk for algae and thus affects the structure and stability of aquatic ecosystems. To investigate the risk of flufiprole to phytoplankton, the digestion and uptake of flufiprole as well as the toxic effects of flufiprole enantiomers and the six metabolites to Chlorella pyrenoidosa were investigated. Flufiprole enantiomers were mainly metabolized to flufiprole amide and detrifluoromethylsulfinyl flufiprole in culture medium, while various metabolites were formed in algae, notably the amide derivative and fipronil. Chlorella pyrenoidosa showed a strong absorption capacity for the flufiprole series. The EC50 values (96 h) indicated that fipronil was the most toxic compound, approximately 5 times as toxic as rac-flufiprole. R-flufiprole was more toxic than S-flufiprole. The contents of chlorophylls, malondialdehyde (MDA), reactive oxygen species (ROS), and total antioxidant capacity (T-AOC) were significantly altered by the chemicals in most cases, especially fipronil. Our results supported the potential detrimental effect of the metabolites of flufiprole on algae.


Assuntos
Chlorella/metabolismo , Inseticidas/metabolismo , Inseticidas/toxicidade , Pirazóis/metabolismo , Pirazóis/toxicidade , Biodegradação Ambiental , Biotransformação , Chlorella/efeitos dos fármacos , Clorofila/metabolismo , Inseticidas/química , Cinética , Malondialdeído/metabolismo , Pirazóis/química , Espécies Reativas de Oxigênio/metabolismo , Estereoisomerismo , Poluentes Químicos da Água/química , Poluentes Químicos da Água/metabolismo , Poluentes Químicos da Água/toxicidade
2.
Chemosphere ; 239: 124672, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31494319

RESUMO

Environmental factors such as temperature and light are the most determinants in the photosynthetic productivity in microalgae. However, under extreme of these conditions, certain resistant microalgae strains possess additional abilities such as growth in the presence of high concentrations of metals and some can improve in combinations of more than one abiotic stress. Therefore, the aim of this research was to evaluate the efficiency in photosynthetic production through the oxygen balance to variations in photon intensity, and under temperature changes in a Cd-resistant strain (DcRCd100) compared to the wild-type strain (Dc1Mwt) of Dictyosphaerium chlorelloides. The results showed that the DcRCd100 strain has the maximum efficiency at 200  µmol m-2 s-1 on photosynthesis net (Pn) (96.32 ±â€¯3.63% nmol O2 ml-1 min-1) as the threshold light saturation, and an adaptation to maintain this maximum photosynthetic gross (Pg) rate at 30 °C (94.99 ±â€¯10.03% nmol O2 ml-1 min-1) due to possible modifications in the photosynthetic apparatus that is reflected in the net evolution rate of O2 to deal with such evaluated conditions. While, Dc1Mwt strain its maximum photosynthetic efficiency was at 300 µmol m-2 s-1 and 21 °C (97.72 ±â€¯2.99 and 99.85 ±â€¯0.30%nmol O2 ml-1 min-1, respectively) and in optimal response to the oxygen balance that is normally achieved by this mesophilic genus. These results provide a new prediction of mechanisms in the oxygen evolution in photosynthesis that rules the correlation between resistance and adaptation to extreme abiotic conditions in metal resistant strains of eukaryotic microalgae.


Assuntos
Cádmio/toxicidade , Chlorella/efeitos dos fármacos , Microalgas/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Adaptação Fisiológica/fisiologia , Chlorella/crescimento & desenvolvimento , Microalgas/crescimento & desenvolvimento , Oxigênio/metabolismo , Taxa Respiratória
3.
Aquat Toxicol ; 217: 105349, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31734626

RESUMO

Ocean acidification, due to increased levels of anthropogenic carbon dioxide, is known to affect the physiology and growth of marine phytoplankton, especially in polar regions. However, the effect of acidification or carbonation on cellular metabolism in polar marine phytoplankton still remains an open question. There is some evidence that small chlorophytes may benefit more than other taxa of phytoplankton. To understand further how green polar picoplankton could acclimate to high oceanic CO2, studies were conducted on an Antarctic Chlorella sp. Chlorella sp. maintained its growth rate (∼0.180 d-1), photosynthetic quantum yield (Fv/Fm = ∼0.69) and chlorophyll a (0.145 fg cell-1) and carotenoid (0.06 fg cell-1) contents under high CO2, while maximum rates of electron transport decreased and non-photochemical quenching increased under elevated CO2. GCMS-based metabolomic analysis reveal that this polar Chlorella strain modulated the levels of metabolites associated with energy, amino acid, fatty acid and carbohydrate production, which could favour its survival in an increasingly acidified ocean.


Assuntos
Chlorella/metabolismo , Metaboloma/efeitos dos fármacos , Microalgas/metabolismo , Água do Mar/química , Aclimatação/efeitos dos fármacos , Aminoácidos/biossíntese , Regiões Antárticas , Dióxido de Carbono/análise , Dióxido de Carbono/toxicidade , Chlorella/efeitos dos fármacos , Clorofila A/metabolismo , Transporte de Elétrons/efeitos dos fármacos , Ácidos Graxos/biossíntese , Concentração de Íons de Hidrogênio , Metabolômica , Microalgas/efeitos dos fármacos , Oceanos e Mares , Fotossíntese/efeitos dos fármacos , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
4.
Artigo em Inglês | MEDLINE | ID: mdl-31627270

RESUMO

The demand for phenolic compounds has been increasing rapidly, which has intensified the production and usage of phenol at a commercial scale. In some polluted water bodies, phenol has become one of the typical aromatic contaminants. Such water bodies are inescapably influenced by nutrients from human activities, and also suffer from nuisance cyanobacterial blooms. While phenolic pollution threatens water safety and ecological balance, algal cells are ubiquitous and sensitive to pollutants. Therefore, effects of phenolic pollution on interspecific competition between a bloom-forming cyanobacterium and other common alga merit quantitative investigation. In this study, the effects of phenol on Microcystis aeruginosa (M. aeruginosa, a bloom-forming cyanobacterium) and Chlorella pyrenoidosa (C. pyrenoidosa, a ubiquitous green alga) were analyzed in mono- and co-cultures. The two species were exposed to a series of phenol treatments (0, 2, 20, and 200 µg mL-1). Population dynamics were measured by a flow cytometer and analyzed by the Lotka-Volterra model. The results showed that M. aeruginosa was more sensitive to phenol (EC50 = 80.8 ± 0.16 µg mL-1) compared to C. pyrenoidosa (EC50 = 631.4 ± 0.41 µg mL-1) in mono-cultures. M. aeruginosa won in the co-cultures when phenol was below or equal to 20 µg mL-1, while C. pyrenoidosa became the dominant species in the 200 µg mL-1 treatment. Photosynthetic activity was measured by a fluometer. Results showed phenol significantly impacted the photosynthetic activity of M. aeruginosa by inhibiting the acceptor side of its photosystem II (PSII), while such inhibition in C. pyrenoidosa was only observed in the highest phenol treatment (200 µg mL-1). This study provides a better understanding for predicting the succession of algal community structure in water bodies susceptible to phenolic contamination. Moreover, it reveals the mechanism on photosynthetic responses of these two species under phenolic stress.


Assuntos
Chlorella/efeitos dos fármacos , Microcystis/efeitos dos fármacos , Fenóis/toxicidade , Fotossíntese/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Chlorella/fisiologia , Microcystis/fisiologia , Especificidade da Espécie
5.
Aquat Toxicol ; 216: 105295, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31561136

RESUMO

Oxybenzone (OBZ; benzophenone-3, CAS# 131-57-7) is a known pollutant of aquatic and marine ecosystems, and is an ingredient in over 3000 personal care products, as well as many types of plastics. The aim of this study is to explore the different toxicities of OBZ on an eukaryotic (Chlorella sp.) and a prokaryotic algae (Arthrospira sp.). OBZ is a photo-toxicant, with all observed toxicities more sever in the light than in the dark. Cell growth and chlorophyll inhibition were positively correlated with increasing OBZ concentrations over time. Twenty days treatment with OBZ, as low as 22.8 ng L-1, significantly inhibited the growth and chlorophyll synthesis of both algae. Both algae were noticeably photo-bleached after 7 days of exposure to OBZ concentrations higher than 2.28 mg L-1. Relatively low OBZ concentrations (0.228 mg L-1) statistically constrained photosynthetic and respiratory rates via directly inhibiting photosynthetic electron transport (PET) and respiration electron transport (RET) mechanisms, resulting in over production of reactive oxygen species (ROS). Transmission and scanning electron microscopy showed that the photosynthetic and respiratory membrane structures were damaged by OBZ exposure in both algae. Additionally, PET inhibition suppressed ATP production for CO2 assimilation via the Calvin-Benson cycle, further limiting synthesis of other biomacromolecules. RET restriction limited ATP generation, restricting the energy supply used for various life activities in the cell. These processes further impacted on photosynthesis, respiration and algal growth, representing secondary OBZ-induced algal damages. The data contained herein, as well as other studies, supports the argument that global pelagic and aquatic phytoplankton could be negatively influenced by OBZ pollution.


Assuntos
Benzofenonas/toxicidade , Chlorella/efeitos dos fármacos , Cosméticos/toxicidade , Spirulina/efeitos dos fármacos , Protetores Solares/toxicidade , Trifosfato de Adenosina/metabolismo , Respiração Celular/efeitos dos fármacos , Forma Celular/efeitos dos fármacos , Chlorella/crescimento & desenvolvimento , Chlorella/ultraestrutura , Clorofila/metabolismo , Transporte de Elétrons/efeitos dos fármacos , Luz , Fotossíntese/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Spirulina/crescimento & desenvolvimento , Spirulina/ultraestrutura , Fatores de Tempo , Poluentes Químicos da Água/toxicidade
6.
Ecotoxicol Environ Saf ; 185: 109691, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31563746

RESUMO

The rational use and the environmental safety of chiral pesticides have attracted significant research interest. Here, enantioselective toxic effects and the selective toxic mechanism of triticonazole (TRZ) against the aquatic microalgae Chlorella pyrenoidosa were studied. The 96h-EC50 values of rac-, (R)-(-)-, and (S)-(+)-TRZ were 1.939, 0.853, and 22.002 mg/L, respectively. At a concentration of 1 mg/L, the contents of photosynthetic pigments of C. pyrenoidosa exposed to (R)-(-)-TRZ were lower than if exposed to S-(+)-form and racemate. Transmission electron microscopic images showed that the R-(-)-form compromised the integrity of cells and disrupted the chloroplast structure. R-(-)-TRZ stimulated vast reactive oxygen species (ROS) and significantly increased superoxide dismutase (SOD) and catalase (CAT) activities, as well as malondialdehyde (MDA) content. For lipid accumulation experiments, nicotinamide adenine dinucleotide (NADH) and triacylglycerol (TAG) accumulations in algal cells treated with R-(-)-TRZ were 171.50% and 280.76%, respectively, compared with the control group. This far exceeded levels of algal cells treated with S-(+)- and rac-TRZ. Based on these data, R-(-)-TRZ was concluded to selectively affect the photosynthetic system, antioxidant system, and lipid synthesis of algal cells, thus causing enantioselective toxic effects of TRZ against C. pyrenoidosa, which indicating that the use of racemate may cause unpredictable environmental harm. Therefore, to reduce the hidden dangers of chiral pesticides for the ecological environment, the environmental risk of TRZ should be evaluated at the stereoselective level.


Assuntos
Chlorella/efeitos dos fármacos , Ciclopentanos/toxicidade , Fungicidas Industriais/toxicidade , Microalgas/efeitos dos fármacos , Triazóis/toxicidade , Poluentes Químicos da Água/toxicidade , Antioxidantes/metabolismo , Chlorella/metabolismo , Chlorella/ultraestrutura , Cloroplastos/efeitos dos fármacos , Cloroplastos/metabolismo , Ciclopentanos/química , Fungicidas Industriais/química , Malondialdeído/farmacologia , Microalgas/metabolismo , Microalgas/ultraestrutura , Fotossíntese/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Estereoisomerismo , Superóxido Dismutase/metabolismo , Triazóis/química , Poluentes Químicos da Água/química
7.
Environ Pollut ; 255(Pt 1): 113149, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31522007

RESUMO

Antibiotics have been widely detected in the ocean and have various impacts on the environment, while knowledge of their chronic influence on phytoplankton, especially red tide algae, is still limited. Dinoflagellates and green algae are common phytoplankton in marine ecosystems. The former is the main red tide algae, and the latter is an important primary producer. We investigated the long-term responses of two representative algae, Prorocentrum lima and Chlorella sp., to two common antibiotics (sulfamethoxazole (SMX) and norfloxacin (NFX)) at environmentally relevant levels (10 and 100 ng/L) during simulated natural conditions. The cell density and activities of three antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD)) were analyzed. The results showed that the influence of each antibiotic on Chlorella sp. was not significant (p > 0.05) during the first 10 days, but the influence of the antibiotics later began to show significant inhibition (p < 0.05) compared with the control group, especially during mixed exposure. P. lima was not inhibited, but its cell density increased. SMX had a superior stimulation effect on P. lima. The three enzymes activities of P. lima increased, and the antioxidant mechanism was not seriously impacted. However, for Chlorella sp., the activity of SOD increased while the activities of CAT and POD decreased, suggesting that this algae's antioxidant system was unbalanced due to oxidative stress. Based on our results, the growth of P. lima was different from green algae Chlorella sp. as well as other inhibited marine algae (such as diatom, golden algae) studied in previous studies. Therefore, as a typical pollutant in the ocean, antibiotics may play a positive role in the bloom of dinoflagellate red tides.


Assuntos
Antibacterianos/farmacologia , Chlorella/efeitos dos fármacos , Dinoflagelados/efeitos dos fármacos , Proliferação Nociva de Algas/efeitos dos fármacos , Norfloxacino/farmacologia , Sulfametoxazol/farmacologia , Poluentes da Água/farmacologia , Antioxidantes/metabolismo , Catalase/metabolismo , Chlorella/metabolismo , Dinoflagelados/metabolismo , Ecossistema , Peroxidase/metabolismo , Peroxidases/metabolismo , Superóxido Dismutase/metabolismo , Fatores de Tempo
8.
Environ Int ; 131: 104992, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31288181

RESUMO

The outstanding commercial application potential of graphene oxide (GO) will inevitably lead to its increasing release into the environment, and then affect the environmental behavior and toxicity of conventional pollutants. Interactions between arsenite [As (III)]/arsenate [As (V)] with GO and their combined toxicity to Chlorella pyrenoidosa were investigated. Under abiotic conditions, approximately 42% of the adsorbed As (III) was oxidized by GO with simulated sunlight illumination, which was induced by electron-hole pairs on the surface of GO. Co-exposure with GO greatly enhanced the toxicity of As (III, V) to alga. When adding 10 mg/L GO, the 72 h median effect concentration of As (III) and As (V) to C. pyrendoidosa decreased to 12.7 and 9.4 mg/L from 30.1 and 16.3 mg/L in the As alone treatment, respectively. One possible mechanism by which GO enhanced As toxicity could be that GO decreased the phosphate concentration in the algal medium, and then increased the accumulation of As (V) in algae. In addition, transmission electron microscope (TEM) images demonstrated that GO acted as a carrier for As (III) and As (V) transport into the algal cells. Also, GO induced severe oxidative stress, which could have subsequently compromised important detoxification pathways (e.g., As complexation with glutathione, As methylation, and intracellular As efflux) in the algal cells. Our findings highlight the significant impact of GO on the fate and toxicity of As in the aquatic environment.


Assuntos
Arseniatos/toxicidade , Arsenitos/toxicidade , Chlorella/efeitos dos fármacos , Grafite/toxicidade , Poluentes Químicos da Água/toxicidade , Adsorção , Arseniatos/metabolismo , Arsenitos/metabolismo , Biotransformação , Grafite/metabolismo , Poluentes Químicos da Água/metabolismo
9.
Chemosphere ; 233: 363-372, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31176899

RESUMO

Titanium dioxide nanoparticles (TiO2 NPs) find applications in our day-to-day life because of unique physicochemical properties. Their release into the aquatic environment poses a possible risk to the organisms. However, the continuing exposure of NPs might reduce their bioavailability to marine organisms owing to aggregation and sedimentation in the aqueous systems thus significantly reducing their toxic impact. In this regard, the present study investigates the effect of continuous exposure of TiO2 NPs to marine microalgae Chlorella sp. under UV-A irradiation through "tanks in series" mode of experiments. In a three-cycle experiment, concentration of TiO2 NPs in the first cycle was fixed at 62.6 µM, and the interacted nanoparticles was subsequently exposed to fresh batches of algae in the next two cycles. After the interaction, the NPs underwent severe aggregation (mean hydrodynamic diameter 3000 ±â€¯18.2 nm after cycle I) leading to gravitational settling in the medium and thus decreased bioavailability. The aggregation can be attributed to interactions between the particles themselves (homo-aggregation) further aggravated by the presence of the algal cells (hetero-aggregation). Cellular viability after cycle I was found to be only 24.2 ±â€¯2.5%, and it was enhanced to 96.5 ±â€¯2.8% after the cycle III in the course of continuous exposure. The results were validated with estimation of oxidative stress markers such as intracellular ROS (total ROS, superoxide and hydroxyl radicals) and LPO after each cycle of exposure. The continuing decrease in the EPS across the cycles further confirmed the diminishing toxicity of the NPs.


Assuntos
Organismos Aquáticos/efeitos dos fármacos , Chlorella/efeitos dos fármacos , Microalgas/efeitos dos fármacos , Nanopartículas/toxicidade , Titânio/toxicidade , Poluentes Químicos da Água/toxicidade , Organismos Aquáticos/metabolismo , Disponibilidade Biológica , Chlorella/metabolismo , Exposição Ambiental , Microalgas/metabolismo , Modelos Teóricos , Nanopartículas/química , Estresse Oxidativo/efeitos dos fármacos , Tamanho da Partícula , Titânio/química , Titânio/metabolismo , Raios Ultravioleta , Poluentes Químicos da Água/química , Poluentes Químicos da Água/metabolismo
10.
Environ Sci Pollut Res Int ; 26(20): 20815-20828, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31111387

RESUMO

The effects of iron (Fe), zinc (Zn), and molybdenum (Mo) on the biomass yield, lipid content, lipid yield, and fatty acid composition of Chlorella sp. NC-MKM, Graesiella emersonii NC-M1, Scenedesmus acutus NC-M2, and Chlorophyta sp. NC-M5 were studied. Among them, G. emersonii NC-M1 recorded the highest percentage increase in lipid content (140.3%) and neutral lipid (50.9%) under Zn-supplemented condition compared to the control. Also, it showed a 105% and 41.88% increase in lipid yield and neutral lipid under Fe-supplemented condition compared to the control. However, Chlorella sp. NC-MKM recorded an elevation in lipid yield (70.3% rise) and neutral lipid (24.32% rise) compared to the control in Mo-supplemented condition. The enhanced production of reactive oxygen species (ROS) and antioxidant enzyme (SOD and POD) under Fe-, Zn-, and Mo-supplemented condition supports the lipid accumulation. FAME analysis showed that the overall percentage of SFA and MUFA increased after the addition of Fe, Zn, and Mo in a culture medium compared to the control which is vital for a good-quality biodiesel. Further, biodiesel properties derived from FAMEs such as CN, SV, IV, CFPP, OS, υ, ρ, and HHV were found in accordance with biodiesel standard.


Assuntos
Ferro/farmacologia , Metabolismo dos Lipídeos/efeitos dos fármacos , Microalgas/efeitos dos fármacos , Molibdênio/farmacologia , Zinco/farmacologia , Biocombustíveis , Chlorella/efeitos dos fármacos , Chlorella/metabolismo , Clorófitas/efeitos dos fármacos , Clorófitas/metabolismo , Meios de Cultura/química , Meios de Cultura/farmacologia , Ácidos Graxos/análise , Lipídeos/química , Microalgas/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Scenedesmus/efeitos dos fármacos , Scenedesmus/metabolismo
11.
Environ Pollut ; 250: 914-921, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31085478

RESUMO

China has been faced with severe haze pollution, which is hazardous to human health. Among the air pollutants, PM2.5 (particles with an aerodynamic diameter ≤ 2.5 µm) is the most dangerous because of its toxicity and impact on human health and ecosystems. However, there has been limited research on PM2.5 particle toxicity. In the present study, we collected daily PM2.5 samples from January 1 to March 31, 2018 and selected samples to extract water-soluble species, including SO42-, NO3-, WSOC, and NH4+. These samples represented clean, good, slight, moderate, and heavy pollution days. After extraction using an ultrasonic method, PM2.5 solutions were obtained. We used Chlorella as the test algae and studied the content of chlorophyll a, as well as the variation in fluorescence when they were placed into the PM2.5 extraction solution, and their submicroscopic structure was analyzed using transmission electron microscopy (TEM). The results showed that when the air quality was relatively clean and good (PM2.5 concentration ≤ 75 µg m-3), the PM2.5 extraction solutions had no inhibiting effects on Chlorella, whereas when the air quality was polluted (PM2.5 concentration > 75 µg m-3) and heavily polluted (PM2.5 concentration > 150 µg m-3), with increasing PM2.5 concentrations and exposure time, the chlorophyll a content in Chlorella decreased. Moreover, the maximum photochemical quantum yield (Fv/Fm) of Chlorella obviously decreased, indicating chlorophyll inhibition during polluted days with increasing PM2.5 concentrations. The effects on the chlorophyll fluorescence parameters were also obvious, leading to an increase of energy dissipated per unit reaction center (DIo/RC), suggesting that Chlorella could survive when exposed to PM2.5 solutions, whereas the physiological activities were significantly inhibited. The TEM analysis showed that there were few effects on Chlorella cell microstructure during clean days, whereas plasmolysis occurred during light- and medium-polluted days. With increasing pollution levels, plasmolysis became more and more apparent, until the organelles inside the cells were thoroughly destroyed and most of the parts could not be recognized.


Assuntos
Poluentes Atmosféricos/toxicidade , Poluição do Ar/análise , Chlorella/efeitos dos fármacos , Monitoramento Ambiental/métodos , Material Particulado/toxicidade , Poluentes Atmosféricos/análise , China , Chlorella/metabolismo , Clorofila A/metabolismo , Humanos , Tamanho da Partícula , Material Particulado/análise , Solubilidade , Testes de Toxicidade , Água/química
12.
Chirality ; 31(6): 468-475, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31066960

RESUMO

Chiral fungicide prothioconazole has a wide range of antifungal spectrum; however, little research has been conducted to evaluate prothioconazole on an enantiomeric level. Five target pathogens and three common aquatic organisms were tested for the enantioselective bioactivity and toxicity of prothioconazole in this work. The antifungal activity of the enantiomers against wheat phytoalexin, rice blast fungus, exserohilum turcicum, Alternaria triticina, and Fusarium avenaceum was determined, and it was found that (-)-prothioconazole were 85 to 2768 times more active than (+)-prothioconazole toward these target organisms. In order to reflect the risk to aquatic ecosystem, the acute toxicity of the enantiomers to Daphnia magna, Chlorella pyrenoidosa, and Lemna minor L. was assessed. It was observed that the toxicity of (-)-prothioconazole to D. magna was 2.2 times higher than (+)-prothioconazole, but it was lower to C. pyrenoidosa and L. minor L. The toxicities of (+)-enantiomer and (-)-enantiomer to D. magna and C. pyrenoidosa were synergy, indicating that the racemate had higher threat to the organisms. It could be concluded that the effects of prothioconazole on target organisms and the acute toxicity to nontarget species were enantioselective with (-)-enantiomer possessing higher efficiency and lower toxicity. Such enantiomeric differences should be taken into consideration when assessing the performance of prothioconazole.


Assuntos
Fungicidas Industriais/química , Fungicidas Industriais/farmacologia , Triazóis/química , Triazóis/toxicidade , Poluentes Químicos da Água/toxicidade , Alternaria/efeitos dos fármacos , Animais , Ascomicetos/efeitos dos fármacos , Chlorella/efeitos dos fármacos , Daphnia/efeitos dos fármacos , Avaliação Pré-Clínica de Medicamentos/métodos , Fungicidas Industriais/toxicidade , Fusarium/efeitos dos fármacos , Magnaporthe/efeitos dos fármacos , Doenças das Plantas/microbiologia , Estereoisomerismo , Testes de Toxicidade Aguda , Triazóis/farmacologia , Poluentes Químicos da Água/química
13.
Artigo em Inglês | MEDLINE | ID: mdl-30995802

RESUMO

Bisphenol A (BPA) is the raw material of 71% of polycarbonate-based resins and 27% of epoxy-based resins which are used for coating metal-based food and beverage cans. Meanwhile, it is taken into account as a typical environmental pollutant. Hormesis may occur in algae exposed to BPA. In this study, the effects of BPA on Chlorella pyrenoidosa were assessed based on growth inhibition and transcriptome analysis. We have focused on two exposure scenarios as follows: (1) exposure to a low stimulation concentration (0.1 mg.L-1, 19.35% promotion in cell density on the 3rd day); (2) exposure to a high inhibition concentration (10 mg.L-1, 64.71% inhibition in cell density on the 3rd day). Transcriptome analysis showed enrichment in nucleotide transport, single-organism transport, cellular respiration. Among them, adenosine triphosphate (ATP) synthase and Nicotinamide adenine dinucleotide (NADH) dehydrogenase were upregulated under 0.1 mg.L-1 BPA treatment. These changes enhanced the physiological and energy metabolic pathways of C. pyrenoidosa, thereby stimulating cell proliferation. At exposure to the high BPA, severe inhibited changes in the expression levels of several pathways were observed, which were related to tricarboxylic acid (TCA) cycle, glycolysis, fatty acid metabolism, oxidative phosphorylation, and photosynthesis. Therefore, BPA could negatively affect growth inhibition through the multiple energy metabolism processes. These results may result in a deeper insight into BPA-induced biphasic responses in algae, and provide vital information to assess the potential ecological risks of exposure to BPA in an aquatic ecosystem.


Assuntos
Compostos Benzidrílicos/farmacologia , Chlorella/efeitos dos fármacos , Chlorella/genética , Perfilação da Expressão Gênica , Fenóis/farmacologia , Ecossistema , Fotossíntese/efeitos dos fármacos
14.
Environ Sci Pollut Res Int ; 26(16): 16195-16209, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30972683

RESUMO

CO2, SO2, and NO are the main components of flue gas and can cause serious environmental issues. Utilization of these compounds in oleaginous microalgae cultivation not only could reduce air pollution but could also produce feedstock for biodiesel production. However, the continuous input of SO2 and NO inhibits microalgal growth. In this study, the toxicity of simulated flue gas (15% CO2, 0.03% SO2, and 0.03% NO, balanced with N2) was reduced through automatic pH feedback control. Integrated lipid production and CO2 fixation with the removal of SO2 and NO was achieved. Using this technique, a lipid content of 38.0% DW was achieved in Chlorella pyrenoidosa XQ-20044. The lipid composition and fatty acid profile indicated that lipid production by C. pyrenoidosa XQ-20044 cultured with flue gas is suitable as a biodiesel feedstock; 81.2% of the total lipids were neutral lipids and 99.5% of the total fatty acids were C16 and C18. The ratio of saturated fatty acids to monounsaturated fatty acids in the microalgal lipid content was 74.5%. In addition, CO2, SO2, and NO from the simulated flue gas were fixed and converted to biomass and lipids with a removal efficiency of 95.9%, 100%, and 84.2%, respectively. Furthermore, the utilization efficiencies of CO2, SO2, and NO were equal to or very close to their removal efficiencies. These results provide a novel strategy for combining biodiesel production with biofixation of flue gas.


Assuntos
Biotecnologia/métodos , Chlorella/efeitos dos fármacos , Chlorella/metabolismo , Lipídeos/biossíntese , Poluentes Atmosféricos/química , Poluentes Atmosféricos/isolamento & purificação , Poluentes Atmosféricos/toxicidade , Biocombustíveis , Biomassa , Biotecnologia/instrumentação , Dióxido de Carbono/isolamento & purificação , Dióxido de Carbono/toxicidade , Chlorella/crescimento & desenvolvimento , Ácidos Graxos/análise , Ácidos Graxos/metabolismo , Concentração de Íons de Hidrogênio , Microalgas/efeitos dos fármacos , Microalgas/crescimento & desenvolvimento , Microalgas/metabolismo , Óxido Nítrico/isolamento & purificação , Óxido Nítrico/toxicidade , Dióxido de Enxofre/isolamento & purificação , Dióxido de Enxofre/toxicidade
15.
Environ Pollut ; 250: 97-106, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30986619

RESUMO

Microalgae are commonly used in ecotoxicity testing due to their ease of culturing and rapid cell division rates. These tests generally utilise a single species of algae; however, microalgae occur in the environment as complex communities of multiple species. To date, routine multispecies toxicity tests using tropical microalgae have not been available. This study investigated four tropical freshwater microalgal species for use in a chronic multispecies toxicity test based on the population growth (cell division) rate: Pediastrum duplex, Monoraphidium arcuatum, Nannochloropsis-like sp. and Chlorella sp. 12. Flow cytometric analysis identified the different fluorescence and light scattering properties of each algal species and quantified each species within multispecies mixtures. Following optimisation of test media nutrients and pH, a toxicity testing protocol was developed with P. duplex, M. arcuatum and Nannochloropsis-like sp. There were no significant differences in growth rates of each alga when tested over 72 h as single species or in multispecies mixtures. Atrazine and imazapic, two herbicides with different modes of action, were used to assess the sensitivity of the multispecies toxicity test. Atrazine was toxic to all species with 72-h IC10 values of 7.2, 63 and 280 µg/L for P. duplex, M. arcuatum and Nannochloropsis-like sp. respectively, while imazapic was not toxic to any species at concentrations up to 1100 µg/L. The toxicity of atrazine and imazapic to each microalgal species in the multispecies toxicity test was the same as that determined from single-species toxicity tests indicating that the presence of these microalgae in a mixture did not affect the toxicity of these two herbicides. This study is the first to develop a multispecies tropical microalgal toxicity test for application in freshwaters. This time- and cost-effective tool can be utilised to generate data to assist environmental decision making and to undertake risk assessments of contaminants in tropical freshwater environments.


Assuntos
Atrazina/toxicidade , Monitoramento Ambiental/métodos , Herbicidas/toxicidade , Imidazóis/toxicidade , Microalgas/efeitos dos fármacos , Ácidos Nicotínicos/toxicidade , Testes de Toxicidade/métodos , Poluentes Químicos da Água/toxicidade , Chlorella/efeitos dos fármacos , Água Doce/química
16.
Environ Sci Pollut Res Int ; 26(15): 15011-15018, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30919190

RESUMO

The combined effect of polystyrene (PS) particles and triphenyltin chloride (TPTCl) to the green algae Chlorella pyrenoidosa was studied. The 96 h IC50 of TPTCl to the green algae C. pyrenoidosa was 30.64 µg/L. The toxicity of PS particles to C. pyrenoidosa was size-dependent, with the 96 h IC50 at 9.10 mg/L for 0.55 µm PS but no toxicity observed for 5.0 µm PS. The exposure to 0.55 µm PS led to damage on structure of algal cells, which could in turn cause inhibition on photosynthesis and population growth of the green algae. TPTCl concentrations in test medium were lowered by 15-19% at presence of 0.55 µm PS particles, indicating a reduced bioavailability of TPTCl. In spite of this reduced bioavailability, the presence of PS increased the toxicity of TPTCl, which might be attributed to facilitated uptake of TPTCl by the green algae after the damage of cell structure. The overall results of the present study provided important information on the effect of PS on the bioavailability and toxicity of TPTCl to phytoplankton species.


Assuntos
Chlorella/efeitos dos fármacos , Compostos Orgânicos de Estanho/toxicidade , Poliestirenos/toxicidade , Poluentes Químicos da Água/toxicidade , Disponibilidade Biológica , Chlorella/citologia , Chlorella/fisiologia , Ecotoxicologia/métodos , Compostos Orgânicos de Estanho/farmacocinética , Fotossíntese/efeitos dos fármacos , Fitoplâncton/efeitos dos fármacos
17.
Aquat Toxicol ; 210: 129-138, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30851487

RESUMO

Metconazole (MEZ) is a broad-spectrum fungicide with four optical stereoisomers. Compared to traditional fungicides, it achieves better control effect at lower dosages. However, its toxicity to non-target organisms has rarely been investigated. This study investigated the stereoselective toxicity of metconazole to Chlorella pyrenoidosa (C. pyrenoidosa). The results indicate that the presence of the racemate and four stereoisomers of MEZ caused a sudden increase of reactive oxygen species (ROS). This in turn stimulated antioxidant defense, impaired photosynthesis and responses of subcellular structure, and eventually inhibited cell growth. The 96 h-EC50 of the racemate, cis-1R,5S-MEZ, cis-1S,5R-MEZ, trans-1S,5S-MEZ, and trans-1R,5R-MEZ were 0.058, 0.182, 0.129, 0.032, and 0.038 mg/L, respectively. Furtheromre, the generation of ROS, antioxidant response, and the loss of photosynthetic function in C. pyrenoidosa were all preferentially trans-1S,5S-MEZ induced. These results aid the understanding of the stereoselective effects of chiral pesticides on C. pyrenoidosa. Such stereoselective differences must be considered when assessing the risk of metconazole to environment.


Assuntos
Antioxidantes/metabolismo , Chlorella/efeitos dos fármacos , Fungicidas Industriais/toxicidade , Fotossíntese/efeitos dos fármacos , Triazóis/toxicidade , Poluentes Químicos da Água/toxicidade , Chlorella/metabolismo , Fungicidas Industriais/química , Espécies Reativas de Oxigênio/metabolismo , Estereoisomerismo , Triazóis/química , Poluentes Químicos da Água/química
18.
Ecotoxicol Environ Saf ; 174: 377-383, 2019 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-30849658

RESUMO

17ß-estradiol (E2) is a steroid estrogen able to affect the reproduction of aquatic organisms even at extremely low concentrations. The behavior of E2 in the presence of chlorella algae was investigated in laboratory experiments. The results showed that the algae's growth was inhibited by 26% after 7 days of culturing in a 2.0 mg L-1 solution of E2. The 96 h EC50 value of 21.46 mg L-1 reflected moderate toxicity. Even low concentrations of E2 were found to affect total chlorophyll and carotenoid levels after 7 and 10 days and to alter stress-generated enzymatic activity in the algae. The efficiency of chlorella's E2 degradation decreased with the increasing of E2 concentration, but 92% of the E2 can be removed from a 0.5 mg L-1 solution over 10 days. The degradation mechanism was speculated. The microalgae suffered relatively less growth inhibition at low E2 concentrations, and their removal effectiveness was then better. The data help to elucidate the interaction between chlorella algae and E2 in an aquatic environment.


Assuntos
Chlorella/efeitos dos fármacos , Estradiol/análise , Microalgas/efeitos dos fármacos , Poluentes Químicos da Água/análise , Antioxidantes/metabolismo , Biodegradação Ambiental , Carotenoides/metabolismo , Chlorella/crescimento & desenvolvimento , Chlorella/metabolismo , Clorofila/metabolismo , Ecotoxicologia , Estradiol/toxicidade , Microalgas/crescimento & desenvolvimento , Microalgas/metabolismo , Modelos Teóricos , Poluentes Químicos da Água/toxicidade
19.
Aquat Toxicol ; 209: 49-55, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30711855

RESUMO

Organophosphorus compounds exhibit a wide range of toxicity to mammals. In this study the effect of malathion on the growth and biochemical parameters of microalgae was evaluated. Three microalgae (Micractinium pusillum UUIND2, Chlorella singulari UUIND5 and Chlorella sorokiniana UUIND6) were used in this study. Among the three algal strains tested, Chlorella sorokiniana UUIND6 was able to tolerate 100 ppm of malathion. The photosynthetic pigments, the protein, carbohydrate and lipid contents of microalgal cells were also analyzed. About 90% degradation was recorded in 25 ppm, 50 ppm and 70% was recorded in 100 ppm of malathion by Chlorella sorokiniana. A mechanism of degradation of malathion by Chlorella sorokiniana is proposed in this study. Activity of carboxylesterase was increased in algal cells cultivated in malathion containing medium which confirmed that malathion degraded into phosphate. Increased amount of Malondialdehye (MDA) indicate the development of free radicals under the stress of malathion which substantialy increase de novo TAG biosynthesis, while increased level of superoxide dismutase (SOD), ascorbate peroxidase (APX) and catalase (CAT) suggested their association in scavenging of free radical.


Assuntos
Carboxilesterase/metabolismo , Microalgas/metabolismo , Compostos Organofosforados/toxicidade , Praguicidas/toxicidade , Triglicerídeos/biossíntese , Biocombustíveis , Biomassa , Tamanho Celular , Chlorella/citologia , Chlorella/efeitos dos fármacos , Chlorella/metabolismo , Inativação Metabólica/efeitos dos fármacos , Malation/toxicidade , Microalgas/citologia , Microalgas/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Espectroscopia de Infravermelho com Transformada de Fourier , Testes de Toxicidade , Poluentes Químicos da Água/toxicidade
20.
Sci Total Environ ; 663: 580-586, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30726766

RESUMO

Benzotriazoles are among the most commonly found organic micropollutants in the aquatic environment. In this study, toxicity experiments were conducted in order to investigate the effects of different benzotriazoles on Chlorella sorokiniana growth. Four compounds were tested; 1H-benzotriazole (BTR), xylytriazole (XTR), 5-methyl-1H-benzotriazole (5TTR) and 5-chlorobenzotriazole (CBTR). The fate of these micropollutants was also studied under batch conditions and the effect of different mechanisms on their elimination was investigated. According to the results, the EC50 values in single-substance toxicity experiments were calculated to 8.3 mg L-1 for BTR, 22 mg L-1 for 5TTR and 38.7 mg L-1 for CBTR. A slight inhibition on microalgae growth was noted at the maximum tested concentration of XTR (77 mg L-1), while no inhibition was observed when a mixture of target BTRs was tested at 200 µg L-1. Calculation of the Risk Quotient (RQ) showed no possible ecological threat in the presence of 5TTR, XTR and CBTR, while RQ values close or higher than 1 were estimated for BTR. All target contaminants were significantly eliminated in microalgae experiments that lasted 16 days. Their removal efficiency ranged between 42.2 ±â€¯3.1% (XTR) to 97.2 ±â€¯0.9% (XTR), while their half-life values were estimated to 2.4 ±â€¯0.5 days for 5TTR, 6.5 ±â€¯0.6 days for BTR, 15.2 ±â€¯1.4 days for CBTR and 20.7 ±â€¯2.0 days for XTR. Photodegradation was the main mechanism affecting BTR, XTR and CBTR removal, while bioremoval processes enhanced 5TTR elimination. The addition of sodium acetate decreased the removal efficiency of BTRs possibly due to catabolite repression. This is the first study investigating the toxicity and fate of BTRs in microalgae cultures.


Assuntos
Chlorella/efeitos dos fármacos , Microalgas/efeitos dos fármacos , Triazóis/toxicidade , Poluentes Químicos da Água/toxicidade , Chlorella/crescimento & desenvolvimento , Microalgas/crescimento & desenvolvimento
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