scholarly journals Comparative analysis of full-length mitochondrial genomes of five Skeletonema species reveals conserved genome organization and recent speciation

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Shuya Liu ◽  
Yichao Wang ◽  
Qing Xu ◽  
Mengjia Zhang ◽  
Nansheng Chen
Keyword(s):  
Molecular Markers ◽  
Coastal Waters ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Phylogenetic Analyses ◽  
Time Estimation ◽  
Single Species ◽  
Full Length ◽  
Comparative Genomic ◽  
Primary Producers

Abstract Background Skeletonema species are prominent primary producers, some of which can also cause massive harmful algal blooms (HABs) in coastal waters under specific environmental conditions. Nevertheless, genomic information of Skeletonema species is currently limited, hindering advanced research on their role as primary producers and as HAB species. Mitochondrial genome (mtDNA) has been extensively used as “super barcode” in the phylogenetic analyses and comparative genomic analyses. However, of the 21 accepted Skeletonema species, full-length mtDNAs are currently available only for a single species, S. marinoi. Results In this study, we constructed full-length mtDNAs for six strains of five Skeletonema species, including S. marinoi, S. tropicum, S. grevillei, S. pseudocostatum and S. costatum (with two strains), which were isolated from coastal waters in China. The mtDNAs of all of these Skeletonema species were compact with short intergenic regions, no introns, and no repeat regions. Comparative analyses of these Skeletonema mtDNAs revealed high conservation, with a few discrete regions of high variations, some of which could be used as molecular markers for distinguishing Skeletonema species and for tracking the biogeographic distribution of these species with high resolution and specificity. We estimated divergence times among these Skeletonema species using 34 mtDNAs genes with fossil data as calibration point in PAML, which revealed that the Skeletonema species formed the independent clade diverging from Thalassiosira species approximately 48.30 Mya. Conclusions The availability of mtDNAs of five Skeletonema species provided valuable reference sequences for further evolutionary studies including speciation time estimation and comparative genomic analysis among diatom species. Divergent regions could be used as molecular markers for tracking different Skeletonema species in the fields of coastal regions.

scholarly journals Occurrence of a single-species cyanobacterial bloom in a lake in Cyprus: monitoring and treatment with hydrogen peroxide-releasing granules

2021 ◽  
Vol 33 (1) ◽  
Author(s):  
Eleni Keliri ◽  
Christia Paraskeva ◽  
Angelos Sofokleous ◽  
Assaf Sukenik ◽  
Dariusz Dziga ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Animal Health ◽  
Cyanobacterial Bloom ◽  
Single Species ◽  
Eutrophic Lake ◽  
Liquid Hydrogen ◽  
Bioactive Metabolites ◽  
Forest Park

AbstractBackgroundExcess loads of nutrients finding their way into waterbodies can cause rapid and excessive growth of phytoplankton species and lead to the formation of cyanobacterial harmful algal blooms (cyano-HABs). Toxic cyanobacteria produce a broad range of bioactive metabolites, some of which are known as cyanotoxins. These metabolites can negatively impact the ecosystem, and human and animal health, thus their presence needs to be closely monitored and mitigated. This study aimed to monitor St. George Lake (Athalassa National Forest Park, Cyprus) for its water quality characteristics, and initiate a new methodology to control the bloom that occurred in the lake during summer 2019, by comparing hydrogen peroxide treatment with novel metallic peroxide granules as source of hydrogen peroxide.ResultsLake monitoring showed that pH, salinity, total dissolved solids and conductivity varied throughout the year, and nutrients concentration was high, indicating a eutrophic lake. The cyanobacteriumMerismopediasp. bloomed in the lake between June and September 2019, comprising up to 99% of the phytoplankton biovolume. The presence of microcystin synthase encoding gene (mcyB, mcyE) was documented, however microcystins were not detected by tandem mass spectroscopy. Treatment with liquid hydrogen peroxide in concentrations 1 to 5 mg L−1had no effect on the phycocyanin fluorescence (Ft) and quantum yield of PSII (Fv/Fm) indicating an ineffective treatment for the denseMerismopediabloom (1 million cells mL−1 ± 20%). Metallic peroxide granules tested for their H2O2releasing capacity in St. George Lake water, showing that CaO2released higher H2O2concentration and therefore have better mitigation efficiency than MgO2granules.ConclusionThe present study highlights the importance of monitoring several water parameters to conclude on the different actions to be taken to limit eutrophication in the catchment area. The findings demonstrated that testing for the presence of genes involved in cyanotoxin production may not be sufficient to follow cyanotoxins in the water, therefore it should be accompanied with analytical confirmation. Treatment experiments indicated that slow release of H2O2from peroxide granules may be an alternative to liquid hydrogen peroxide when applied in appropriate doses, but further investigation is needed before it is applied at the field.Graphic Abstract

Global classification and evolution of brushlegged mayflies (Insecta: Ephemeroptera: Oligoneuriidae): phylogenetic analyses of morphological and molecular data and dated historical biogeography

2019 ◽  
Vol 187 (2) ◽  
pp. 378-412 ◽  
Author(s):  
Fabiana Criste Massariol ◽  
Daniela Maeda Takiya ◽  
Frederico Falcão Salles
Keyword(s):  
Phylogenetic Analyses ◽  
Divergence Time ◽  
Time Estimation ◽  
Single Species ◽  
Molecular Data ◽  
Neotropical Region ◽  
Fossil Species ◽  
Divergence Time Estimation ◽  
The Family ◽  
Family Based

AbstractOligoneuriidae is a Pantropical family of Ephemeroptera, with 68 species described in 12 genera. Three subfamilies are recognized: Chromarcyinae, with a single species from East Asia; Colocrurinae, with two fossil species from Brazil; and Oligoneuriinae, with the remaining species distributed in the Neotropical, Nearctic, Afrotropical and Palaearctic regions. Phylogenetic and biogeographical analyses were performed for the family based on 2762 characters [73 morphological and 2689 molecular (COI, 16S, 18S and 28S)]. Four major groups were recovered in all analyses (parsimony, maximum likelihood and Bayesian inference), and they were assigned to tribal level, namely Oligoneuriini, Homoeoneuriini trib. nov., Oligoneuriellini trib. nov. and Elassoneuriini trib. nov. In addition, Yawari and Madeconeuria were elevated to genus level. According to Statistical Dispersal-Vicariance (S-DIVA), Dispersal Extinction Cladogenesis (DEC) and divergence time estimation analyses, Oligoneuriidae originated ~150 Mya in the Gondwanan supercontinent, but was probably restricted to the currently delimited Neotropical region. The initial divergence of Oligoneuriidae involved a range expansion to Oriental and Afrotropical areas, sometime between 150 and 118 Mya. At ~118 Mya, the family started its diversification, reaching the Nearctic through dispersal from the Neotropical region and the Palaearctic and Madagascar from the Afrotropical region.

scholarly journals Action Plan for Monitoring, Mitigation and Management of Harmful Algal Blooms in the Coastal Waters of Oman

2007 ◽  
Vol 12 (2) ◽  
pp. 75
Author(s):  
A.Y.A AlKindi ◽  
H.M.H. Al-Ghelani ◽  
S. Amer ◽  
Y.K Al-Akhzami
Keyword(s):  
Coastal Waters ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Red Tide ◽  
Action Plan ◽  
Rapid Response System ◽  
Gulf Of Oman ◽  
Trichodesmium Erythraeum ◽  
Response System ◽  
Adverse Impacts

The Gulf of Oman, an ecologically and economically rich ecosystem, is frequently impacted by occurrences of harmful algal blooms. Recent studies indicate an increase in the number of causative species and harmful impacts. Many red tide incidents in Oman have been found leading to hypoxia. The frequent bloom forming species here are Karenia selliformis, Nitzschia pungens, Prorocentrum arabianum and Trichodesmium erythraeum. We review work carried out in this area, and we propose here a Management Action Plan for not only an effective monitoring system for harmful algal blooms (HABs), but also mitigation of their adverse impacts and rapid response system.   

Dead Zones

2021 ◽  
Author(s):  
David L. Kirchman
Keyword(s):  
Cover Crops ◽  
Precision Agriculture ◽  
Coastal Waters ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Biological Diversity ◽  
Oxygen Depletion ◽  
Waterborne Diseases ◽  
Buffer Zones ◽  
Dead Zones

This book explores the many rivers, lakes, and oceans that are losing oxygen. Aquatic habitats with little dissolved oxygen are called dead zones because nothing can live there except some microbes. The number and size of dead zones are increasing worldwide. The book shows that oxygen loss causes fish kills, devastates bottom-dwelling biota, reduces biological diversity, and rearranges aquatic food webs. In the 19th century in rich countries and in poor regions today, dead zones are accompanied by waterborne diseases that kill thousands of people. The open oceans are losing oxygen because of climate change, whereas dead zones in coastal waters and seas are caused by excessive nutrients, which promote excessive growth of algae and eventually oxygen depletion. Work by Gene Turner and Nancy Rabalais demonstrated that nutrients in the Gulf of Mexico come from fertilizers used in the US Midwest, home to the most productive cropland in the world. Agriculture is also the biggest source of nutrients fuelling dead zones in the Baltic Sea and other coastal waters. Today, fertilizers contaminate drinking water and kick-start harmful algal blooms in local lakes and reservoirs. Nutrient pollution in some regions has declined because of buffer zones, cover crops, and precision agriculture, but more needs to be done. The book concludes by arguing that each of us can do our part by changing our diet; eating less, especially eating less red meat, would improve our health and the health of the environment. A better diet could reduce the amount of greenhouse gas emitted by agriculture and shrink dead zones worldwide.

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