scholarly journals Abundant Allelochemicals and the Inhibitory Mechanism of the Phenolic Acids in Water Dropwort for the Control of Microcystis aeruginosa Blooms

Plants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2653
Author(s):  
Jixiang Liu ◽  
Yajun Chang ◽  
Linhe Sun ◽  
Fengfeng Du ◽  
Jian Cui ◽  
...  
Keyword(s):  
Microcystis Aeruginosa ◽  
Phenolic Acids ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Inhibitory Effect ◽  
Simultaneous Action ◽  
Inhibitory Effects ◽  
Chl A ◽  
Ferulic Acids ◽  
Water Dropwort

In recent years, with the frequent global occurrence of harmful algal blooms, the use of plant allelopathy to control algal blooms has attracted special and wide attention. This study validates the possibility of turning water dropwort into a biological resource to inhibit the growth of harmful Microcystis aeruginosa blooms via allelopathy. The results revealed that there were 33 types of allelopathic compounds in the water dropwort culture water, of which 15 were phenolic acids. Regarding water dropwort itself, 18 phenolic acids were discovered in all the organs of water dropwort via a targeted metabolomics analysis; they were found to be mainly synthesized in the leaves and then transported to the roots and then ultimately released into culture water where they inhibited M. aeruginosa growth. Next, three types of phenolic acids synthesized in water dropwort, i.e., benzoic, salicylic, and ferulic acids, were selected to clarify their inhibitory effects on the growth of M. aeruginosa and their mechanism(s) of action. It was found that the inhibitory effect of phenolic acids on the growth of M. aeruginosa increased with the increase of the exposure concentration, although the algae cells were more sensitive to benzoic acid than to salicylic and ferulic acids. Further study indicated that the inhibitory effects of the three phenolic acids on the growth of M. aeruginosa were largely due to the simultaneous action of reducing the number of cells, damaging the integrity of the cell membrane, inhibiting chlorophyll a (Chl-a) synthesis, decreasing the values of F0 and Fv/Fm, and increasing the activity of the antioxidant enzymes (SOD, POD, and CAT) of M. aeruginosa. Thus, the results of this study indicate that both culture water including the rich allelochemicals in water dropwort and biological algae inhibitors made from water dropwort could be used to control the growth of noxious algae in the future.

scholarly journals The Mechanism Insight Into the Inhibitory Effect of Artemisinin Sustained-release Inhibitors With Different Particle Sizes on Microcystis aeruginosa

2021 ◽  
Author(s):  
Zhiyun Jiang ◽  
lixiao Ni ◽  
Xianglan Li ◽  
Chu Xu ◽  
Xuqing Chen ◽  
...  
Keyword(s):  
Cell Membrane ◽  
Sustained Release ◽  
Chlorophyll A ◽  
Microcystis Aeruginosa ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Algal Cell ◽  
Inhibitory Effect ◽  
Inhibitory Mechanism ◽  
Irreversible Damage

Abstract Environment-friendly algaecides based on allelopathy have been widely used to control harmful algal blooms. In this research, micro nano scale artemisinin sustained-release algal inhibitor was prepared, the optimal preparation conditions were explored and the inhibitory mechanism of artemisinin algaecides was perfected. The results showed that when the particle size of artemisinin sustained-release microspheres (ASMs) was 2/10000 of artemisinin sustained-release granules (ASGs), the inhibitory effect was more remarkable. The optimal concentration of ASMs was 0.2 g L-1, and the inhibitory effect reached 99% on the 10th day; The algae density and chlorophyll-a both showed a downward trend, indicating that ASGs and ASMs could promote the degradation of chlorophyll-a; The inhibition rate of ASGs was faster than that of ASMs on the 4th day, and the inhibitory effect of ASMs was more significant after the 5th day. The activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) increased rapidly at first and then decreased, which indicated that ASGs and ASMs caused oxidative damage to Microcystis aeruginosa (M. aeruginosa) and inhibited the activity of antioxidant enzymes. Furthermore, the content of the oxygen free radical (O2-) and malondialdehyde (MDA) continued to rise after the 5th day, the protein, nucleic acid and conductivity in the culture medium increased. These results showed that lipid peroxidation occurred in the algal cell membrane, and the permeability of the membrane increased. In summary, the ASMs had significant continuous inhibitory effect while the ASGs had better short-term effect. The main inhibitory mechanism of artemisinin algaecides is the irreversible damage of cell membrane.

scholarly journals Unsteady Multi-Element Time Series Analysis and Prediction Based on Spatial-Temporal Attention and Error Forecast Fusion

2020 ◽  
Vol 12 (2) ◽  
pp. 34
Author(s):  
Xiaofan Wang ◽  
Lingyu Xu
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Short Term Memory ◽  
Sudden Change ◽  
Back Propagation ◽  
Red Tides ◽  
Model Errors ◽  
Chl A ◽  
Error Forecast ◽  
Concentration Prediction

Harmful algal blooms (HABs) often cause great harm to fishery production and the safety of human lives. Therefore, the detection and prediction of HABs has become an important issue. Machine learning has been increasingly used to predict HABs at home and abroad. However, few of them can capture the sudden change of Chl-a in advance and handle the long-term dependencies appropriately. In order to address these challenges, the Long Short-Term Memory (LSTM) based spatial-temporal attentions model for Chlorophyll-a (Chl-a) concentration prediction is proposed, a model which can capture the correlation between various factors and Chl-a adaptively and catch dynamic temporal information from previous time intervals for making predictions. The model can also capture the stage of Chl-a when values soar as red tide breaks out in advance. Due to the instability of the current Chl-a concentration prediction model, the model is also applied to make a prediction about the forecast reliability, to have a basic understanding of the range and fluctuation of model errors and provide a reference to describe the range of marine disasters. The data used in the experiment is retrieved from Fujian Marine Forecasts Station from 2009 to 2011 and is combined into 8-dimension data. Results show that the proposed approach performs better than other Chl-a prediction algorithms (such as Attention LSTM and Seq2seq and back propagation). The result of error prediction also reveals that the error forecast method possesses established advantages for red tides prevention and control.

scholarly journals Algicidal Activity of Novel Indigenous Bacterial Strain, Paracoccus Sp., Against Harmful Algal Bloom Species, Karenia Mikimotoi

2021 ◽  
Author(s):  
Ning Ding ◽  
Wenjun Du ◽  
Yanlou Feng ◽  
Yuhao Song ◽  
Chao Wang ◽  
...  
Keyword(s):  
Bacterial Strain ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Harmful Algal Bloom ◽  
Growth Conditions ◽  
Inhibitory Effect ◽  
Algicidal Bacteria ◽  
Rrna Gene ◽  
Negative Effects ◽  
Karenia Mikimotoi

Abstract Harmful algal blooms have deleterious effects on aquatic ecosystems and human health. The application of algicidal bacteria is a promising and environmentally friendly method of preventing and eradicating harmful algal blooms. In this study, a screen for algicidal agents against harmful algal blooms was used to identify an algicidal bacterial strain isolated from a Karenia mikimotoi culture. Strain O-1 exhibited a strong inhibitory effect on harmful K. mikimotoi and was identified as a Paracoccus species via 16S rRNA gene sequence analysis. This strain killed K. mikimotoi by secreting active algicidal compounds, which were stable at temperatures of -80–121 °C, but these substances were sensitive to strongly acidic conditions. The algicidal properties of strain O-1 against K. mikimotoi were cell density- and time-dependent. No significant changes or negative effects were noted for two other Chlorophyta species, which highlighted the specificity of the studied algicidal substance. Finally, single-factor experiments revealed the optimum growth conditions of strain O-1 under different pH and temperature conditions. Strain O-1 therefore has potential as a bio-agent for reducing the biomass of harmful K. mikimotoi blooms.

scholarly journals Transcriptional Analysis of Microcystis aeruginosa Co-Cultured with Algicidal Bacteria Brevibacillus laterosporus

2021 ◽  
Vol 18 (16) ◽  
pp. 8615
Author(s):  
Yulei Zhang ◽  
Dong Chen ◽  
Ning Zhang ◽  
Feng Li ◽  
Xiaoxia Luo ◽  
...  
Keyword(s):  
Microcystis Aeruginosa ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Control Method ◽  
Acid Synthesis ◽  
Transcriptional Analysis ◽  
Economic Losses ◽  
Algicidal Bacteria ◽  
Brevibacillus Laterosporus ◽  
Expression Of Genes

Harmful algal blooms caused huge ecological damage and economic losses around the world. Controlling algal blooms by algicidal bacteria is expected to be an effective biological control method. The current study investigated the molecular mechanism of harmful cyanobacteria disrupted by algicidal bacteria. Microcystis aeruginosa was co-cultured with Brevibacillus laterosporus Bl-zj, and RNA-seq based transcriptomic analysis was performed compared to M. aeruginosa, which was cultivated separately. A total of 1706 differentially expressed genes were identified, which were mainly involved in carbohydrate metabolism, energy metabolism and amino acid metabolism. In the co-cultured group, the expression of genes mainly enriched in photosynthesis and oxidative phosphorylation were significantly inhibited. However, the expression of the genes related to fatty acid synthesis increased. In addition, the expression of the antioxidant enzymes, such as 2-Cys peroxiredoxin, was increased. These results suggested that B. laterosporus could block the electron transport by attacking the PSI system and complex I of M. aeruginosa, affecting the energy acquisition and causing oxidative damage. This further led to the lipid peroxidation of the microalgal cell membrane, resulting in algal death. The transcriptional analysis of algicidal bacteria in the interaction process can be combined to explain the algicidal mechanism in the future.

scholarly journals The Use of Sentinel-3 Imagery to Monitor Cyanobacterial Blooms

Environments ◽  
2019 ◽  
Vol 6 (6) ◽  
pp. 60 ◽  
Author(s):  
Igor Ogashawara
Keyword(s):  
Remote Sensing ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Lake Erie ◽  
Water Governance ◽  
Spectral Band ◽  
Cyanobacterial Blooms ◽  
Chl A ◽  
Cyanobacterial Harmful Algal Blooms ◽  
New Algorithms

Cyanobacterial harmful algal blooms (CHABs) have been a concern for aquatic systems, especially those used for water supply and recreation. Thus, the monitoring of CHABs is essential for the establishment of water governance policies. Recently, remote sensing has been used as a tool to monitor CHABs worldwide. Remote monitoring of CHABs relies on the optical properties of pigments, especially the phycocyanin (PC) and chlorophyll-a (chl-a). The goal of this study is to evaluate the potential of recent launch the Ocean and Land Color Instrument (OLCI) on-board the Sentinel-3 satellite to identify PC and chl-a. To do this, OLCI images were collected over the Western part of Lake Erie (U.S.A.) during the summer of 2016, 2017, and 2018. When comparing the use of traditional remote sensing algorithms to estimate PC and chl-a, none was able to accurately estimate both pigments. However, when single and band ratios were used to estimate these pigments, stronger correlations were found. These results indicate that spectral band selection should be re-evaluated for the development of new algorithms for OLCI images. Overall, Sentinel 3/OLCI has the potential to be used to identify PC and chl-a. However, algorithm development is needed.

scholarly journals Inhibitory effects of Pontederia cordata on the growth of Microcystis aeruginosa

2018 ◽  
Vol 2017 (1) ◽  
pp. 99-107 ◽  
Author(s):  
Yanping Qian ◽  
Ning Xu ◽  
Juan Liu ◽  
Runan Tian
Keyword(s):  
Microcystis Aeruginosa ◽  
Inhibitory Effect ◽  
Butyl Alcohol ◽  
Inhibition Rate ◽  
Inhibitory Effects ◽  
Fibrous Root ◽  
Pontederia Cordata ◽  
Algal Inhibition ◽  
Organic Extracts ◽  
Acetone Extracts

Abstract This study investigated the effect of Pontederia cordata on Microcystis aeruginosa growth in three different experimental settings: (i) co-cultivation, (ii) exposure of cyanobacteria to culture water of P. cordata, and (iii) exposure of M. aeruginosa to organic extracts of P. cordata. Results showed that the growth of M. aeruginosa was significantly inhibited by co-cultivation, with the highest inhibition rate of 61.9% within 5 days. Moreover, 95% culture water with P. cordata could markedly inhibit the growth of M. aeruginosa, with inhibition rate of 98.3% on day 6, indicating that most of the algal cells died. The organic extracts of fibrous root showed stronger inhibition effect than the leaf and stalk extracts. Acetone extract of fibrous root showed the strongest inhibitory effect on M. aeruginosa. Different components of 80% acetone extracts from fibrous root exhibited varied effects on the growth of M. aeruginosa. Ethyl acetate and water components had strong inhibition effects on M. aeruginosa. By contrast, n-butyl alcohol components had weak inhibition effects, and hexane components even promoted the growth of M. aeruginosa. Allelochemicals of P. cordata were primarily released into the water through the fibrous root. Results indicated that P. cordata can be applied in environmentally friendly algal inhibition.

scholarly journals LSTM Networks to Improve the Prediction of Harmful Algal Blooms in the West Coast of Sabah

2021 ◽  
Vol 18 (14) ◽  
pp. 7650
Author(s):  
Fatin Nadiah Yussof ◽  
Normah Maan ◽  
Mohd Nadzri Md Reba
Keyword(s):  
West Coast ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Time Series Data ◽  
Short Term Memory ◽  
Harmful Algal Bloom ◽  
Series Data ◽  
Severe Illness ◽  
The West ◽  
Chl A

Harmful algal bloom (HAB) events have alarmed authorities of human health that have caused severe illness and fatalities, death of marine organisms, and massive fish killings. This work aimed to perform the long short-term memory (LSTM) method and convolution neural network (CNN) method to predict the HAB events in the West Coast of Sabah. The results showed that this method could be used to predict satellite time series data in which previous studies only used vector data. This paper also could identify and predict whether there is HAB occurrence in the region. A chlorophyll a concentration (Chl-a; mg/L) variable was used as an HAB indicator, where the data were obtained from MODIS and GEBCO bathymetry. The eight-day dataset interval was from January 2003 to December 2018. The results obtained showed that the LSTM model outperformed the CNN model in terms of accuracy using RMSE and the correlation coefficient r as the statistical criteria.

scholarly journals Fatty acids from the cyanobacterium Microcystis aeruginosa with potent inhibitory effects on fish gill Na+/K+-ATPase activity.

1998 ◽  
Vol 201 (1) ◽  
pp. 81-89
Author(s):  
N R Bury ◽  
G A Codd ◽  
S E Wendelaaar Bonga ◽  
G Flik
Keyword(s):  
Fatty Acids ◽  
Microcystis Aeruginosa ◽  
Basolateral Membrane ◽  
Tight Binding ◽  
Oreochromis Mossambicus ◽  
Inhibitory Effect ◽  
Cyanobacterial Blooms ◽  
Inhibitory Effects ◽  
Fish Kills ◽  
Layer Chromatography

Fatty acids from two strains of the cyanobacterium Microcystis aeruginosa, PCC 7820 (a strain that produces the hepatotoxin microcystin-LR, MC-LR) and CYA 43 (a strain that produces only small quantities of MC-LR), were extracted, partially characterised and tested for their inhibitory effect on the K+-dependent p-nitrophenol phosphatase (pNPPase) activity of tilapia (Oreochromis mossambicus) gill basolateral membrane. Thin-layer chromatography of the lipids from dichloromethane:methanol extracts of M. aeruginosa PCC 7820 and CYA 43, using diethylether:isopropanol:formic acid (100:4.5:2.5) as solvent, yielded five inhibitory products from M. aeruginosa 7820 and six from M. aeruginosa CYA 43. None of these products could be related to MC-LR. The inhibitory behaviour of the products mimics that of a slow, tight-binding inhibitor. The inhibitory activity is removed by incubation of extracts with fatty-acid-free bovine serum albumin (FAF-BSA). However, FAF-BSA only partially reversed the inhibition of K+-dependent pNPPase on fish gills pre-exposed to the extracted products. We conclude that M. aeruginosa strains PCC 7820 and CYA 43 produce fatty acids with potent inhibitory effects on K+-dependent pNPPase. The release of these products following lysis of cyanobacterial blooms may help to explain fish kills through a disturbance of gill functioning.

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