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 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 Bacilysin from Bacillus amyloliquefaciens FZB42 Has Specific Bactericidal Activity against Harmful Algal Bloom Species

2014 ◽  
Vol 80 (24) ◽  
pp. 7512-7520 ◽  
Author(s):  
Liming Wu ◽  
Huijun Wu ◽  
Lina Chen ◽  
Shanshan Xie ◽  
Haoyu Zang ◽  
...  
Keyword(s):  
Bactericidal Activity ◽  
Bacillus Amyloliquefaciens ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Harmful Algal Bloom ◽  
Algal Cell ◽  
Algal Species ◽  
Inhibitory Effect ◽  
Cell Organelle ◽  
Content Type

ABSTRACTHarmful algal blooms, caused by massive and exceptional overgrowth of microalgae and cyanobacteria, are a serious environmental problem worldwide.In the present study, we looked forBacillusstrains with sufficiently strong anticyanobacterial activity to be used as biocontrol agents. Among 24 strains,Bacillus amyloliquefaciensFZB42 showed the strongest bactericidal activity againstMicrocystis aeruginosa, with a kill rate of 98.78%. The synthesis of the anticyanobacterial substance did not depend on Sfp, an enzyme that catalyzes a necessary processing step in the nonribosomal synthesis of lipopeptides and polyketides, but was associated with thearogene cluster that is involved in the synthesis of thesfp-independent antibiotic bacilysin. Disruption ofbacB, the gene in the cluster responsible for synthesizing bacilysin, or supplementation with the antagonistN-acetylglucosamine abolished the inhibitory effect, but this was restored when bacilysin synthesis was complemented. Bacilysin caused apparent changes in the algal cell wall and cell organelle membranes, and this resulted in cell lysis. Meanwhile, there was downregulated expression ofglmS,psbA1,mcyB, andftsZ—genes involved in peptidoglycan synthesis, photosynthesis, microcystin synthesis, and cell division, respectively. In addition, bacilysin suppressed the growth of other harmful algal species. In summary, bacilysin produced byB. amyloliquefaciensFZB42 has anticyanobacterial activity and thus could be developed as a biocontrol agent to mitigate the effects of harmful algal blooms.

scholarly journals Performance of a Handheld Chlorophyll-a Fluorometer: Potential Use for Rapid Algae Monitoring

Water ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1409
Author(s):  
Hamdhani Hamdhani ◽  
Drew E. Eppehimer ◽  
David Walker ◽  
Michael T. Bogan
Keyword(s):  
Chlorophyll A ◽  
Surface Waters ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Water Quality Monitoring ◽  
Ambient Light ◽  
Calibration Equation ◽  
Field Samples ◽  
Potential Use

Chlorophyll-a measurements are an important factor in the water quality monitoring of surface waters, especially for determining the trophic status and ecosystem management. However, a collection of field samples for extractive analysis in a laboratory may not fully represent the field conditions. Handheld fluorometers that can measure chlorophyll-a in situ are available, but their performance in waters with a variety of potential light-interfering substances has not yet been tested. We tested a handheld fluorometer for sensitivity to ambient light and turbidity and compared these findings with EPA Method 445.0 using water samples obtained from two urban lakes in Tucson, Arizona, USA. Our results suggested that the probe was not sensitive to ambient light and performed well at low chlorophyll-a concentrations (<25 µg/L) across a range of turbidity levels (50–70 NTU). However, the performance was lower when the chlorophyll-a concentrations were >25 µg/L and turbidity levels were <50 NTU. To account for this discrepancy, we developed a calibration equation to use for this handheld fluorometer when field monitoring for potential harmful algal blooms in water bodies.

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 Temporal dynamics of the phytoplankton community associated with environmental factors and harmful algal blooms in Acapulco Bay, Mexico

2021 ◽  
Vol 49 (1) ◽  
pp. 110-124
Author(s):  
Victor A. Cervantes-Urieta ◽  
Ma. Nieves Trujillo-Tapia ◽  
Juan Violante-González ◽  
Giovanni Moreno-Díaz ◽  
Agustín A. Rojas-Herrera ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Chlorophyll A ◽  
Rainy Season ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Temporal Dynamics ◽  
Harmful Algal Bloom ◽  
San Lorenzo ◽  
Diatom Genus ◽  
Physical And Chemical

The phytoplankton community's temporal variability associated with environmental factors and harmful algal blooms in Acapulco Bay was analyzed. Phytoplankton samples were taken monthly at three sites (MSL: Morro de San Lorenzo, CDO: Casa Díaz Ordaz, and PP: Playa Palmitas) over 11 months in 2018. The physical and chemical variables of surface water were measured in situ, and the composition and community structure of phytoplankton were analyzed. The physical and chemical characteristics studied varied significantly. The highest temperatures were obtained in September and October (September: 29.6 ± 3.58°C, October: 34.61 ± 1.83°C), whereas the highest salinities and chlorophyll-a concentrations occurred from February to May (salinity: 34.06 ± 0.38, chlorophyll-a: 2.73 ± 0.15 μg L-1). The highest oxygen concentrations were recorded during the rainy season (June 91.8% and December 100%). A total of 201 phytoplankton species were identified: 94 diatoms, 101 dinoflagellates, 4 cyanobacteria, and 2 silicoflagellates. Diatoms dominated during the rainy season, whereas dinoflagellates dominated during the dry season (June to December). A total of 17 harmful species were identified; four toxin-producing species included a diatom genus (Pseudonitszchia sp.) and three dinoflagellate species (Gymnodinium catenatum, Dinophysis caudata, and Phalacroma rotundata). One species that produces oxygen reactive species and hemolysis (Margalefidinium polykrikoides) caused a harmful algal bloom at the CDO and PP stations. The temperature is one of the most critical factors for its bloom in October.

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.

Using artificial intelligence for CyanoHAB niche modeling: discovery and visualization of Microcystis–environmental associations within western Lake Erie

2014 ◽  
Vol 71 (11) ◽  
pp. 1642-1654 ◽  
Author(s):  
David F. Millie ◽  
Gary R. Weckman ◽  
Gary L. Fahnenstiel ◽  
Hunter J. Carrick ◽  
Ehsan Ardjmand ◽  
...  
Keyword(s):  
Chlorophyll A ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Lake Erie ◽  
Three Dimensional ◽  
Response Surfaces ◽  
Ecological Niche Models ◽  
Wind Speeds ◽  
Western Lake ◽  
Western Lake Erie

Cyanobacterial harmful algal blooms (CyanoHABs), mainly composed of the genus Microcystis, occur frequently throughout the Laurentian Great Lakes. We used artificial neural networks (ANNs) involving 31 hydrological and meteorological predictors to model total phytoplankton (as chlorophyll a) and Microcystis biomass from 2009 to 2011 in western Lake Erie. Continuous ANNs provided modeled-measured correspondences (and modeling efficiencies) ranging from 0.87 to 0.97 (0.75 to 0.94) and 0.71 to 0.90 (0.45 to 0.88) for training–cross-validation and test data subsets of chlorophyll a concentrations and Microcystis biovolumes, respectively. Classification ANNs correctly assigned up to 94% of instances for Microcystis presence–absence. The influences of select predictors on phytoplankton and CyanoHAB niches were visualized using biplots and three-dimensional response surfaces. These then were used to generate mathematical expressions for the relationships between modeled CyanoHAB outcomes and the direct and interactive influences of environmental factors. Based on identified conditions (∼40 to 50 μg total phosphorus (TP)·L−1, 22 to 26 °C, and prolonged wind speeds less than ∼19 km·h−1) underlying the likelihood of occurrence and accumulation of phytoplankton and Microcystis, a “target” concentration of 30 μg TP·L−1 appears appropriate for alleviating blooms. ANNs generated robust ecological niche models for Microcystis, providing a predictive framework for quantitative visualization of nonlinear CyanoHAB–environmental interactions.

Inhibitory mechanisms of Acacia mearnsii extracts on the growth of Microcystis aeruginosa

2015 ◽  
Vol 71 (6) ◽  
pp. 856-861 ◽  
Author(s):  
Zhibin Liu ◽  
Lirong Zhou ◽  
Dandan Liu ◽  
Qiyu Zhu ◽  
Wenqing Chen
Keyword(s):  
Cell Membrane ◽  
Microcystis Aeruginosa ◽  
Plant Extract ◽  
Algal Cell ◽  
Common Species ◽  
Cyanobacterial Blooms ◽  
Cell Membrane Permeability ◽  
Acacia Mearnsii ◽  
Inhibitory Mechanisms

Our previous work revealed that Acacia mearnsii extract can inhibit the growth of Microcystis aeruginosa, the common species forming toxic cyanobacterial blooms in eutrophic freshwater. In the present study, we demonstrated that this plant extract can significantly increase cell membrane permeability and Ca2+/Mg2+-ATPase activity on the membrane. Long-term exposure to concentrations of 20 ppm A. mearnsii extract led to algal cell membrane leakage or even lysis. Comparison of expression of three photosynthesis-related genes (rbcL, psaB and psbD) in M. aeruginosa with and without plant extract treatment revealed that their expression was remarkably reduced in the presence of the extract. Down-regulation of photosynthesis-related genes could indicate the inhibition of the photosynthetic process. Thus, our results suggested that both photosynthetic systems and membranes of M. aeruginosa are potentially damaged by A. mearnsii extract.

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