scholarly journals Genetic detection of freshwater harmful algal blooms: A review focused on the use of environmental DNA (eDNA) in Microcystis aeruginosa and Prymnesium parvum

Harmful Algae ◽  
2021 ◽  
Vol 110 ◽  
pp. 102124
Author(s):  
Sheena M. Feist ◽  
Richard F. Lance
Author(s):  
Yulei Zhang ◽  
Dong Chen ◽  
Ning Zhang ◽  
Feng Li ◽  
Xiaoxia Luo ◽  
...  

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.


2018 ◽  
Vol 46 (2) ◽  
pp. 413-421 ◽  
Author(s):  
Ben A. Wagstaff ◽  
Edward S. Hems ◽  
Martin Rejzek ◽  
Jennifer Pratscher ◽  
Elliot Brooks ◽  
...  

Prymnesium parvum is a toxin-producing microalga that causes harmful algal blooms globally, which often result in large-scale fish kills that have severe ecological and economic implications. Although many toxins have previously been isolated from P. parvum, ambiguity still surrounds the responsible ichthyotoxins in P. parvum blooms and the biotic and abiotic factors that promote bloom toxicity. A major fish kill attributed to P. parvum occurred in Spring 2015 on the Norfolk Broads, a low-lying set of channels and lakes (Broads) found on the East of England. Here, we discuss how water samples taken during this bloom have led to diverse scientific advances ranging from toxin analysis to discovery of a new lytic virus of P. parvum, P. parvum DNA virus (PpDNAV-BW1). Taking recent literature into account, we propose key roles for sialic acids in this type of viral infection. Finally, we discuss recent practical detection and management strategies for controlling these devastating blooms.


2012 ◽  
Vol 69 (8) ◽  
pp. 1389-1404 ◽  
Author(s):  
Daniel L. Roelke ◽  
Bryan W. Brooks ◽  
James P. Grover ◽  
George M. Gable ◽  
Leslie Schwierzke-Wade ◽  
...  

Effects of inflow on phytoplankton dynamics and assemblage structure have long been an interest of ecologists and resource managers, especially when they are linked to the incidence of harmful algal blooms. The frequency and magnitude of Prymnesium parvum bloom-preventing inflows likely in a drier landscape of south-central USA was explored, along with the relative importance of various factors important to blooms. We show that the number of large inflow events necessary to prevent blooms might decrease between 25% and 65% under drier conditions likely for this region. Long duration inflow events that are critical to lake flushing could nearly disappear, with inflow events lasting longer than 20 days decreasing 40-fold. These findings suggest that the frequency of P. parvum blooms and fish-kill events might increase in this region with human population and climate change. Multivariate analyses of monitoring data from multiple lakes indicate that other factors may be equally important to bloom occurrences. Inverse trends between toxic bloom events and nutrient concentrations, cyanobacteria, and lower pH are apparent. During periods when P. parvum populations were not toxic, an inverse relationship with zooplankton was observed. These other factors might be harnessed to mitigate P. parvum blooms in the future when inflows are reduced.


2019 ◽  
Author(s):  
Emily Jacobs-Palmer ◽  
Ramón Gallego ◽  
Ana Ramón-Laca ◽  
Emily Kunselman ◽  
Kelly Cribari ◽  
...  

ABSTRACTSeagrass beds provide a variety of ecosystem services, both within and outside the bounds of the habitat itself. Here we use environmental DNA (eDNA) amplicons to analyze a broad cross-section of taxa from ecological communities in and immediately surrounding eelgrass (Zostera marina). Sampling seawater along transects extending alongshore outward from eelgrass beds, we demonstrate that eDNA provides meter-scale resolution of communities in the field. We evaluate eDNA abundance indices for thirteen major phylogenetic groups of marine and estuarine taxa along these transects, finding highly local changes linked with proximity to Z. marina for a diverse group of dinoflagellates, and for no other group of taxa. Eelgrass habitat is consistently associated with dramatic reductions in dinoflagellate abundance both within the contiguous beds and for at least fifteen meters outside, relative to nearby sites without eelgrass. These results are consistent with the hypothesis that eelgrass-associated communities have allelopathic effects on dinoflagellates, and that these effects can extend in a halo beyond the bounds of the contiguous beds. Because many dinoflagellates are capable of forming Harmful Algal Blooms (HABs) toxic to humans and other animal species, the apparent salutary effect of eelgrass habitat on neighboring waters has important implications for public health as well as shellfish aquaculture and harvesting.


2021 ◽  
Vol 12 ◽  
Author(s):  
Morag Clinton ◽  
Elżbieta Król ◽  
Dagoberto Sepúlveda ◽  
Nikolaj R. Andersen ◽  
Andrew S. Brierley ◽  
...  

The gill of teleost fish is a multifunctional organ involved in many physiological processes, including protection of the mucosal gill surface against pathogens and other environmental antigens by the gill-associated lymphoid tissue (GIALT). Climate change associated phenomena, such as increasing frequency and magnitude of harmful algal blooms (HABs) put extra strain on gill function, contributing to enhanced fish mortality and fish kills. However, the molecular basis of the HAB-induced gill injury remains largely unknown due to the lack of high-throughput transcriptomic studies performed on teleost fish in laboratory conditions. We used juvenile rainbow trout (Oncorhynchus mykiss) to investigate the transcriptomic responses of the gill tissue to two (high and low) sublethal densities of the toxin-producing alga Prymnesium parvum, in relation to non-exposed control fish. The exposure time to P. parvum (4–5 h) was sufficient to identify three different phenotypic responses among the exposed fish, enabling us to focus on the common gill transcriptomic responses to P. parvum that were independent of dose and phenotype. The inspection of common differentially expressed genes (DEGs), canonical pathways, upstream regulators and downstream effects pointed towards P. parvum-induced inflammatory response and gill inflammation driven by alterations of Acute Phase Response Signalling, IL-6 Signalling, IL-10 Signalling, Role of PKR in Interferon Induction and Antiviral Response, IL-8 Signalling and IL-17 Signalling pathways. While we could not determine if the inferred gill inflammation was progressing or resolving, our study clearly suggests that P. parvum blooms may contribute to the serious gill disorders in fish. By providing insights into the gill transcriptomic responses to toxin-producing P. parvum in teleost fish, our research opens new avenues for investigating how to monitor and mitigate toxicity of HABs before they become lethal.


Fishes ◽  
2018 ◽  
Vol 3 (1) ◽  
pp. 11 ◽  
Author(s):  
Morten Svendsen ◽  
Nikolaj Andersen ◽  
Per Hansen ◽  
John Steffensen

2019 ◽  
Vol 5 (1) ◽  
pp. 140-151 ◽  
Author(s):  
Sara Dia ◽  
Ibrahim Alameddine ◽  
Mutasem El-Fadel

Cyanobacterial harmful algal blooms (HABs) are an emerging problem worldwide, affecting many important freshwater systems.


Plants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2653
Author(s):  
Jixiang Liu ◽  
Yajun Chang ◽  
Linhe Sun ◽  
Fengfeng Du ◽  
Jian Cui ◽  
...  

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.


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