ENVIRONMENTAL POLLUTION
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2019
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IF 5.714
Zhiguang Niu,Wei’an Xu,Jing Na,Zhiwei Lv,Ying Zhang
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.
研究领域:
海洋生物学
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环境科学
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DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
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2019
·Vol. 26
·期 23
·23763-23776
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IF 2.914
Xiao Xi,Li Chao,Huang Haomin,Lee Ying Ping
Red tides that occur off coasts have become a worldwide phenomenon over the past decades. In order to mitigate the damage of the red tides on the aquatic ecosystems, it is crucial to develop a method for predicting algicidal activities that requires less labor and time, and most importantly, this method can quickly screen potential algicides to control red tides. In this study, we have investigated the algicidal activity of 19 natural flavonoids against a typical red tide alga, Phaeocystis globosa. Our results indicate that after 5 days of flavonoid exposure, the half inhibition concentrations (IC 50 ) ranged from 0.068 to 3.065 mg L −1 , which showed the strong algicidal activities of the flavonoids. Furthermore, quantitative structure activity relationship (QSAR) model has been carried out between negative scale logarithm (pIC 50 ) of the flavonoids and the corresponding molecular descriptors. The developed model was validated, both internally and externally, which displayed statistical robustness ( R 2 = 0.867, p = 0.0002, Q 2 LOO = 0.825, RMSEC = 0.182, Q 2 extF3 = 0.896, RMSEP = 0.161, CCC = 0.935). This indicates that the developed model was obtained successfully with satisfactory predictability and robustness for the future rapid screening of natural flavonoids with high inhibition activity on the red tide alga growth. Moreover, the main descriptors in the QSAR model were the molar refractivity, partition coefficient, lowest unoccupied molecular orbital, and highest occupied molecular orbital, illustrating that the molecular electro-chemical characteristics are significant in the algicidal actions of the flavonoids.
Red tides frequently occur worldwide and have become a global environment problem. Flavonoids showed great potential in allelopathic control of the excessive growth of red tide algae. In this study, the algicidal activity of 19 natural flavonoids was investigated on a typical red tide organism Phaeocystis globosa . Futhermore, we applied the quantitative structure-activity relationship (QSAR) model to the experimental data. The model between molecular descriptors of flavonoids and their antialgal activity displays statistical robustness, and 4 of 45 selected molecular descriptors were obtained by regression of training set. The numbers in the figure represent the half inhibition concentration (IC 50 ) of flavonoids. Our results show that the algicidal activity of flavonoids is closely related to molar refraction, partition coefficient, lowest unoccupied molecular orbital, and highest occupied molecular orbital. The QSAR model can efficaciously predict the algicidal activity and provide insights into the inhibitory mechanisms of flavonoids.
研究领域:
海洋生态学
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环境毒理学
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化学生态学
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藻类生物学
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QSAR模型
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DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
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2022
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IF 10.753
Zhongshi Wang,Zhiming Yu,Liyan He,Jianan Zhu,Lidong Liu,Xiuxian Song
Electrophysiology studies the electrical properties of cells and tissues including bioelectrical signals and membrane ion channel activities. As an important means to reveal ion channel related physiological functions and the underlying mechanisms, electrophysiological techniques have been widely used in studies of animals, higher plants and algae that are closely related to higher plants. However, few electrophysiological studies have been carried out in red tide organisms, especially in dinoflagellates, which is mainly due to the complex surface structure of dinoflagellate amphiesma. In this study, the surface amphiesma of Alexandrium pacificum , a typical red tide species, was removed by centrifugation, low-temperature treatment and enzymatic treatment. In all three treatments, low-temperature treatment with 4 °C for 2 h had high ecdysis rate and high fixation rate, and the treated cells were easy to puncture, so low-temperature treatment was used as a preprocessing treatment for subsequent current recording. Acquired protoplasts of A. pacificum were identified by calcofluor fluorescence and immobilized by poly-lysine. A modified “puncture” single-electrode voltage-clamp recording was first applied to dinoflagellates, and voltage-gated currents, which had the characteristics of outward K + current and inward Cl − current, were recorded and confirmed by ion replacement, indicating the voltage-gated currents were mixed. This method can be used as a technical basis for the electrophysiological study of dinoflagellates and provides a new perspective for the study of stress tolerance, red tide succession, and the regulation of physiological function of dinoflagellates.
研究领域:
海洋生物学
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电生理学
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细胞生物学
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环境科学
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DOI
PubMed
高影响因子
Frontiers in Marine Science
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2022
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IF 5.247
Liu Zhengyu,Yu Zhiming,Cao Xihua,Jiang Wenbin,Yuan Yongquan,Song Xiuxian
Red tide is a kind of marine disaster caused by the accumulation or proliferation of microalgae and other organisms in a short period of time, and utilizing modified clay to control and inhibit red tide is the preferred method. Among them, the application potential of organic-modified clay is high; unlike inorganic and microbial modifications, it has a broad-spectrum removal capacity on red tide algae at extremely low dosages. However, it has some disadvantages such as severe toxicity and high residual turbidity, leading to several limitations in its practical application. Therefore, it has become urgent to select organic-modified reagents with higher efficiency, weaker toxicity and lower residual turbidity. In this study, the typical red tide alga——Prorocentrum donghaiense was selected to detect the removal capacity of Polydimethyl diallyl ammonium chloride (PDMDAAC) modified clay (MP) by comparing with the Hexadecyl trimethyl ammonium bromide (HDTMA) modified clay (MH). Not only the physiological stress and flocculation effects of two modified clays on microalgae had been discussed, but also the properties of the modified clays had been characterized in this study. The results showed that the low degree of oxidative stress and less damage to the cell membrane make MP more environmentally friendly, PDMDAAC can remove microalgae at a low dose (2 mg/L) and quickly clarify the water by significantly enhancing the flocculation capacity of clay. In addition to discussing the removal mechanism of two modified clays on microalgae, schematic diagrams of the pathways were drafted. This study will provide support for the development of organic-modified clay.
研究领域:
海洋生物学
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环境科学
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DOI
高影响因子
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