scholarly journals Tracing the active genetic diversity of Microcystis and Microcystis phage through a temporal survey of Taihu

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0244482
Author(s):  
Helena L. Pound ◽  
Steven W. Wilhelm
Keyword(s):  
Environmental Factors ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Community Dynamics ◽  
Expression Patterns ◽  
Temporal Shift ◽  
Expression Of Genes ◽  
Single Genus ◽  
Microcystis Wesenbergii ◽  
And Oxidative Stress

Harmful algal blooms are commonly thought to be dominated by a single genus, but they are not homogenous communities. Current approaches, both molecular and culture-based, often overlook fine-scale variations in community composition that can influence bloom dynamics. We combined homology-based searches (BLASTX) and phylogenetics to distinguish and quantify Microcystis host and phage members across a summer season during a 2014 Microcystis- dominated bloom that occurred in Lake Tai (Taihu), China. We found 47 different genotypes of the Microcystis-specific DNA-dependent RNA polymerase (rpoB), which included several morphospecies. Microcystis flos-aquae and Microcystis wesenbergii accounted for ~86% of total Microcystis transcripts, while the more commonly studied Microcystis aeruginosa only accounted for ~7%. Microcystis genotypes were classified into three temporal groups according to their expression patterns across the course of the bloom: early, constant and late. All Microcystis morphospecies were present in each group, indicating that expression patterns were likely dictated by competition driven by environmental factors, not phylogeny. We identified three primary Microcystis-infecting phages based on the viral terminase, including a novel Siphoviridae phage that may be capable of lysogeny. Within our dataset, Myoviridae phages consistent with those infecting Microcystis in a lytic manner were positively correlated to the early host genotypes, while the Siphoviridae phages were positively correlated to the late host genotypes, when the Myoviridae phages express putative genetic markers for lysogeny. The expression of genes in the microcystin-encoding mcy cassette was estimated using mcyA, which revealed 24 Microcystis-specific genotypes that were negatively correlated to the early host genotypes. Of all environmental factors measured, pH best described the temporal shift in the Microcystis community genotypic composition, promoting hypotheses regarding carbon concentration mechanisms and oxidative stress. Our work expounds on the complexity of HAB events, using a well-studied dataset to highlight the need for increased resolution of community dynamics.

Viewpoints of Dominant Environmental Factors Influencing Algal Blooms

2011 ◽  
Vol 66-68 ◽  
pp. 155-159
Author(s):  
Di Guan ◽  
Da Wen Gao ◽  
Nan Qi Ren ◽  
Yi Fan Li
Keyword(s):  
Environmental Factors ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Meteorological Factors ◽  
Chlorophyll Concentration ◽  
Phytoplankton Growth ◽  
High Biomass ◽  
Coupling Effects ◽  
Factors Influencing

Harmful algal blooms (HABs) are generally known as excessive phytoplankton growth or rapidly concentrate to high biomass. This study summarized the situation of HABs in China, and discussed possible dominant factors stimulating algal blooms by analyzing several actual HABs cases. It was manifested nutrients may affect algae concentration principally, but such impact tended to decease with degradation of background water. Meanwhile the hydrological and meteorological factors expressed greater correlation to chlorophyll concentration under multiple coupling effects of complex environmental factors. For the complex mechanisms, the determination of principle factors which stimulate excessive algal blooms effectively still need further researches, which are suggested to conduct under overall considerations on 3 scales: macro dimension, medium dimension and micro dimension.

Influence of non-nutrient environmental factors on Ulva pertusa's inhibitory effects on Heterosigma akashiwo growth

2015 ◽  
Vol 96 (5) ◽  
pp. 1041-1052
Author(s):  
Qiu Jin ◽  
Han-Gui Wu ◽  
Xin-Xin Zhang ◽  
Zhong-Lu Ke
Keyword(s):  
Environmental Factors ◽  
Growth Inhibition ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Optimal Growth ◽  
High Irradiance ◽  
Heterosigma Akashiwo ◽  
Inhibitory Influence ◽  
Single Factor ◽  
Green Macroalgae

We studied the effects of four non-nutrient environmental factors (temperature, salinity, irradiance and pH) on the growth inhibition of the macroalgae Ulva pertusa (Chlorophyta) upon the microalgae Heterosigma akashiwo (Rhaphidophyta). Experiments were conducted in single-factor incubation and various two-factor combination experiments in which temperature (10, 15, 25 and 30°C), salinity (10, 20, 30 and 40 g kg−1 water), irradiance (20, 100, 200 and 400 μmol m−2 s−1), and pH (5.5, 7, 8.5 and 10) were varied systematically. The growth rates of U. pertusa and H. akashiwo and the rate of microalgal growth inhibition were altered significantly by changing some of the non-nutrient factors in both the single-factor and the two-factor experiments. The optimal growth conditions for U. pertusa were 20–25°C, salinity of 30 g kg−1, irradiance level of 200–400 μmol m−2 s−1, and pH 8.5–10; optimal conditions for H. akashiwo growth were 25°C, 30 g kg−1, 100 μmol m−2 s−1 and pH 8.5, respectively. The growth inhibitory influence of U. pertusa on H. akashiwo was strongest at 25°C with low salinity (10 g kg−1), high irradiance (400 μmol m−2 s−1) and high alkalinity (pH = 10). The results of this study may be helpful in the development of methods for using green macroalgae to control the proliferation of microalgae in harmful algal blooms (HABs). In particular, these findings provide guidance regarding optimum levels of non-nutrient environmental factors in confined areas, such as aquaculture factories.

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.

scholarly journals Biosynthesis of the neurotoxin domoic acid in a bloom-forming diatom

Science ◽  
2018 ◽  
Vol 361 (6409) ◽  
pp. 1356-1358 ◽  
Author(s):  
John K. Brunson ◽  
Shaun M. K. McKinnie ◽  
Jonathan R. Chekan ◽  
John P. McCrow ◽  
Zachary D. Miles ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Gene Cluster ◽  
Molecular Basis ◽  
Harmful Algal Blooms ◽  
Transcriptome Sequencing ◽  
Algal Blooms ◽  
Domoic Acid ◽  
Genetic Basis ◽  
Toxin Production ◽  
Growth Conditions

Oceanic harmful algal blooms of Pseudo-nitzschia diatoms produce the potent mammalian neurotoxin domoic acid (DA). Despite decades of research, the molecular basis for its biosynthesis is not known. By using growth conditions known to induce DA production in Pseudo-nitzschia multiseries, we implemented transcriptome sequencing in order to identify DA biosynthesis genes that colocalize in a genomic four-gene cluster. We biochemically investigated the recombinant DA biosynthetic enzymes and linked their mechanisms to the construction of DA’s diagnostic pyrrolidine skeleton, establishing a model for DA biosynthesis. Knowledge of the genetic basis for toxin production provides an orthogonal approach to bloom monitoring and enables study of environmental factors that drive oceanic DA production.

scholarly journals Heat Shock Protein 70 and 90 Genes in the Harmful DinoflagellateCochlodinium polykrikoides: Genomic Structures and Transcriptional Responses to Environmental Stresses

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Ruoyu Guo ◽  
Seok Hyun Youn ◽  
Jang-Seu Ki
Keyword(s):  
Heat Shock ◽  
Heat Shock Protein ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Phylogenetic Analyses ◽  
Expression Patterns ◽  
Genomic Analysis ◽  
Environmental Stresses ◽  
Transcriptional Responses ◽  
Intergenic Spacers

The marine dinoflagellateCochlodinium polykrikoidesis responsible for harmful algal blooms in aquatic environments and has spread into the world’s oceans. As a microeukaryote, it seems to have distinct genomic characteristics, like gene structure and regulation. In the present study, we characterized heat shock protein (HSP) 70/90 ofC. polykrikoidesand evaluated their transcriptional responses to environmental stresses. Both HSPs contained the conserved motif patterns, showing the highest homology with those of other dinoflagellates. Genomic analysis showed that theCpHSP70had no intron but was encoded by tandem arrangement manner with separation of intergenic spacers. However,CpHSP90had one intron in the coding genomic regions, and no intergenic region was found. Phylogenetic analyses of separate HSPs showed that CpHSP70 was closely related with the dinoflagellateCrypthecodinium cohniiand CpHSP90 with other Gymnodiniales in dinoflagellates. Gene expression analyses showed that bothHSPgenes were upregulated by the treatments of separate algicides CuSO4and NaOCl; however, they displayed downregulation pattern with PCB treatment. The transcription ofCpHSP90andCpHSP70showed similar expression patterns under the same toxicant treatment, suggesting that both genes might have cooperative functions for the toxicant induced gene regulation in the dinoflagellate.

scholarly journals Spatiotemporal variability and environmental factors of harmful algal blooms (HABs) over western Lake Erie

PLoS ONE ◽  
2017 ◽  
Vol 12 (6) ◽  
pp. e0179622 ◽  
Author(s):  
Di Tian ◽  
Gengxin Xie ◽  
Jing Tian ◽  
Kuo-Hsin Tseng ◽  
C. K. Shum ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Lake Erie ◽  
Spatiotemporal Variability ◽  
Western Lake ◽  
Western Lake Erie
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