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1.
J Environ Manage ; 260: 110106, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32090819

RESUMO

In this study, a new electrocoagulation electrode configuration has been investigated in order to induce dielectrophoretic (DEP) force for the enhanced harvesting of marine microalgae (Tetraselmis sp.). Asymmetrical aluminum electrodes with an alternative current power supply were used. The impact of electrode configuration, current density and electrolysis time were evaluated. A maximum algal harvesting efficiency of 90.9% was achieved using 7.1 mA/cm2 current density and 10 min electrolysis time. The energy consumption was found to be 4.62 kWh/kg of microalgae. The major significance of using the new electrode configuration was found in the aluminum content in the harvested biomass which decreased by 52% compared to the conventional symmetrical electrocoagulation electrodes.


Assuntos
Clorófitas , Microalgas , Alumínio , Biomassa , Eletrocoagulação , Eletrodos , Eletrólise
2.
3.
Bioresour Technol ; 300: 122594, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31901774

RESUMO

The optimization of the BG-11 culture medium nutrients using complex statistical design followed by incremental illumination was planned to stimulate the Haematococcus pluvialis growth and astaxanthin accumulation. Based on the Plackett-Burman design results, MgSO4·7H2O, H3BO3, and Na2CO3 were identified as critical components to improve the biomass and astaxanthin productivity. Using central composite design, their initial critical concentrations in the green stage were found as 57.5, 6.2 and 53.0 mg/L, while for the red stage, the 138.3, 8.5 and 41.0 mg/L, recorded as optimum respectively. Using the optimum media, growth and astaxanthin accumulation at the end of the phototrophic and photoinduction stages were boosted by 17 and 54% respectively. The results of scale-up coupled with incremental illumination in phototrophic stage revealed the biomass and astaxanthin concentration improved 50% and 60% over the BG-11 media under constant light intensity. Also, different optimum culture medium formula for green and red stages was proposed.


Assuntos
Clorófitas , Biomassa , Luz , Nutrientes , Xantofilas
4.
Ecotoxicol Environ Saf ; 190: 110089, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31896472

RESUMO

The use of algae to adsorb heavy metals is an efficient and environmentally friendly treatment for contaminated water and has attracted widespread research attention. In this study, a meta-analysis of the heavy metal adsorption capacity of algae from five different phyla and the factors influencing these capacities was conducted. Phaeophyta was found to have a high heavy metal adsorption capacity, whereas Bacillariophyta had a relatively low adsorption capacity; Chlorophyta, Rhodophyta, and Cyanophyta had moderate adsorption capacities. Non-living algae were more effective in practical applications than living algae were. Algal biomass had a relatively high adsorption efficiency of 1-10 g/L, which did not increase significantly when algal concentration increased. The algal adsorption efficiency for initial heavy metal concentrations of 10-100 mg/L was higher than for concentrations of greater than 100 mg/L. The results further show that algal adsorption of heavy metals reached a maximum capacity of 80-90% within 20 min. Heavy metal adsorption by algae was not temperature-dependent, and it was more effective in moderately to weakly acidic environments (pH = 4-7.5). Considering these aspects for practical applications, algae from some phyla can effectively be used for heavy metal biosorption in contaminated water.


Assuntos
Clorófitas/metabolismo , Metais Pesados/metabolismo , Poluentes Químicos da Água/metabolismo , Adsorção , Biomassa , Concentração de Íons de Hidrogênio , Feófitas , Rodófitas , Temperatura Ambiente
5.
BMC Bioinformatics ; 21(1): 1, 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31898485

RESUMO

BACKGROUND: The green microalga Dunaliella salina accumulates a high proportion of ß-carotene during abiotic stress conditions. To better understand the intracellular flux distribution leading to carotenoid accumulation, this work aimed at reconstructing a carbon core metabolic network for D. salina CCAP 19/18 based on the recently published nuclear genome and its validation with experimental observations and literature data. RESULTS: The reconstruction resulted in a network model with 221 reactions and 212 metabolites within three compartments: cytosol, chloroplast and mitochondrion. The network was implemented in the MATLAB toolbox CellNetAnalyzer and checked for feasibility. Furthermore, a flux balance analysis was carried out for different light and nutrient uptake rates. The comparison of the experimental knowledge with the model prediction revealed that the results of the stoichiometric network analysis are plausible and in good agreement with the observed behavior. Accordingly, our model provides an excellent tool for investigating the carbon core metabolism of D. salina. CONCLUSIONS: The reconstructed metabolic network of D. salina presented in this work is able to predict the biological behavior under light and nutrient stress and will lead to an improved process understanding for the optimized production of high-value products in microalgae.


Assuntos
Carbono/metabolismo , Clorófitas/metabolismo , Microalgas/metabolismo , Carbono/química , Carotenoides/química , Carotenoides/metabolismo , Clorófitas/química , Clorófitas/efeitos da radiação , Cloroplastos/química , Cloroplastos/metabolismo , Citosol/química , Citosol/metabolismo , Luz , Redes e Vias Metabólicas , Microalgas/química , Microalgas/efeitos da radiação , Mitocôndrias/química , Mitocôndrias/metabolismo , Modelos Biológicos , Estresse Fisiológico
6.
Bioresour Technol ; 300: 122699, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31901515

RESUMO

The impact of four different growth conditions on the cell disruption efficiency of Neochloris oleoabundans was investigated. A mechanical and biological cell disruption methods were evaluated separately and combined. It has been established that microalgae grown in marine water under nitrogen deprivation were the most resistant against cell disruption methods and released the lowest amount of proteins. The release of lipids, however, followed the "hindered molecule diffusion phenomenon" because it did not follow the same release pattern as proteins. The enzymatic treatment was efficient enough to release the majority of the proteins without combining it with high-pressure homogenization. Regarding energy input, Neochloris oleoabundans grown in marine water under nitrogen deprivation required the highest energy input to release proteins (Ep = 13.76 kWh.kg-1) and to break the cells by high-pressure homogenization (Ex - HPH = 1.14 kWh.kg-1) or by the combination of enzymes and High-pressure homogenization (Ex - ENZ = 2.79 kWh.kg-1).


Assuntos
Clorófitas , Microalgas , Biomassa , Lipídeos , Nitrogênio
7.
Plant Dis ; 104(1): 161-167, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31660796

RESUMO

Orange cane blotch (OCB), an algal disease on commercial blackberry plants in the southeastern United States, has been an increasing concern among producers. The causal agent, Cephaleuros virescens, produces brightly colored green to orange lesions on blackberry stems, but proof of actual damage and impact on crop yield has not been documented. Naturally infected stem sections were viewed using transmission and scanning electron microscopy to evaluate cane damage. Surface abrasions, intercellular growth, and occasional intracellular growth were observed on the surface and epidermal layers. Field studies at four commercial sites over 2 years were conducted to assess the impact of OCB on yield in 'Ouachita' blackberry plants not treated with algicidal chemicals. Neither cane diameter nor berry size was impacted by severity of OCB; however, berry number decreased with increasing OCB intensity in a nonlinear manner, thereby resulting in reduced yields.


Assuntos
Clorófitas , Doenças das Plantas , Rubus , Agricultura , Clorófitas/fisiologia , Frutas , Georgia , Doenças das Plantas/parasitologia , Rubus/parasitologia
8.
Bioresour Technol ; 297: 122385, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31761625

RESUMO

This work mainly studied B. braunii adapted to different CO2 concentrations with cobalt enrichment, and developed a process for CO2 capture, hydrocarbon production and cobalt removal. The results showed that B. braunii favored rapid growth at 5.0% (v/v) CO2, and the highest biomass was 1.89 g.L-1 with 4.5 mg.L-1 of cobalt. Hydrocarbon productivity in high concentration CO2 (5.0% and 10.0%) with cobalt enrichment was higher than that in Chu 13 medium. The change in cobalt removal efficiency mainly corresponded to the growth of B. braunii. The LCE of B. braunii in cobalt-rich with high CO2 concentration (5.0% and 10.0%) was 15.7%, and 14.9%, respectively, which was higher than that in normal medium. CO2 fixation rates were also higher in cobalt enrichment coupled with high CO2 concentration. This study not only provides ideas for the removal of toxic metal cobalt, but also has great potential for CO2 biofixation.


Assuntos
Dióxido de Carbono , Clorófitas , Biomassa , Cobalto , Hidrocarbonetos
9.
Prep Biochem Biotechnol ; 50(1): 98-105, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31809237

RESUMO

Nitrogen, being one of the building blocks of biomacromolecules, is an important nutrient for microalgae growth. Nitrogen availability alters the growth and biochemical composition of microalgae. We investigated the effects of different nitrogen concentrations on specific growth rate (SGR), biomass productivity (BP), total protein and lipid content and amino acid and fatty acid composition of Desmodesmus communis. Nitrogen deficiency increased algal growth and changed the lipid amount and composition. The maximum growth and BP were detected in 75% N-medium. The highest total protein and lipid amount were detected in 50% N- and 75% N-media, respectively. Amino acid and fatty acid compositions of samples varied widely depending on the nutrient concentrations. The amount of unsaturated fatty acid (USFAs) was higher than saturated fatty acid (SFAs) and Linolenic acid percentage is higher than the limit of European standards in all media. The data reported here provide important contributions how nitrogen scarcity and abundance affect the growth and biochemical content of microalgae and this information can further be utilized in culture optimization in studies aimed at microalgae production for biofuels.


Assuntos
Biomassa , Clorófitas/crescimento & desenvolvimento , Microalgas/crescimento & desenvolvimento , Nitrogênio/metabolismo , Aminoácidos/análise , Aminoácidos/metabolismo , Clorófitas/metabolismo , Meios de Cultura/análise , Meios de Cultura/metabolismo , Ácidos Graxos/análise , Ácidos Graxos/metabolismo , Metabolismo dos Lipídeos , Lipídeos/análise , Microalgas/metabolismo , Nitrogênio/análise , Proteínas de Plantas/análise , Proteínas de Plantas/metabolismo
10.
Biochim Biophys Acta Bioenerg ; 1861(2): 148139, 2020 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-31825812

RESUMO

An aerial green alga, Prasiola crispa (Lightf.) Menegh, which is known to form large colonies in Antarctic habitats, is subject to severe environmental stresses due to low temperature, draught and strong sunlight in summer. A considerable light-absorption by long-wavelength chlorophylls (LWC) at around 710 nm, which seem to consist of chlorophyll a, was detected in thallus of P. crispa harvested at a terrestrial environment in Antarctica. Absorption level at 710 nm against that at 680 nm was correlated with fluorescence emission intensity at 713 nm at room temperature and the 77 K fluorescence emission band from LWC was found to be emitted at 735 nm. We demonstrated that the LWC efficiently transfer excitation energy to photosystem II (PSII) reaction center from measurements of action spectra of photosynthetic oxygen evolution and P700 photo-oxidation. The global quantum yield of PSII excitation in thallus by far-red light was shown to be as high as by orange light, and the excitation balance between PSII and PSI was almost same in the two light sources. It is thus proposed that the LWC increase the photosynthetic productivity in the lower parts of overlapping thalli and contribute to the predominance of alga in the severe environment.


Assuntos
Clorofila A/metabolismo , Clorófitas/metabolismo , Luz , Complexo de Proteína do Fotossistema II/metabolismo , Regiões Antárticas , Complexos de Proteínas Captadores de Luz/metabolismo , Oxigênio/metabolismo , Complexo de Proteína do Fotossistema I/metabolismo , Espectrometria de Fluorescência
11.
Anal Bioanal Chem ; 412(3): 589-599, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31838555

RESUMO

The green microalga Haematococcus pluvialis has been widely studied due to its capacity to accumulate great amounts of astaxanthin, a high-value carotenoid with biological activities. In the present work, two green compressed fluid-based processes, pressurized liquid extraction (PLE) and supercritical antisolvent fractionation (SAF), are integrated to obtain an astaxanthin-enriched extract from this microalga. PLE was carried out using pressurized ethanol as solvent, for 20 min, at 10 MPa, and 50 °C as extraction temperature. Subsequently, the obtained extract was processed by SAF to further purify the carotenoid fraction. The SAF process was optimized using a 3-level factorial experimental design and considering three experimental variables: (i) CO2 pressure (10-30 MPa), (ii) percentage of water in the PLE extract (20-50%), and (iii) PLE extract/supercritical-CO2 flow rate ratio (0.0125-0.05). Total carotenoid content was evaluated in both extracts and raffinates. Best results were obtained at 30 MPa, 0.05 feed/SC-CO2 mass flow rate, and 20% (v/v) of water in the feed solution, achieving values of 120.3 mg g-1 carotenoids in extract (in the SAF extract fraction), which were significantly higher than those obtained in the original PLE extract. In parallel, a new fast two-dimensional comprehensive liquid chromatography (LC×LC) method was optimized to get the full carotenoid profile of these extracts in less than 25 min. This is the first time that the use of a C30 column is reported in an on-line LC×LC system. Graphical abstract.


Assuntos
Clorófitas/química , Cromatografia Líquida/métodos , Espectrometria de Massas/métodos , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Espectrofotometria Ultravioleta , Xantofilas/química
12.
Ecotoxicol Environ Saf ; 188: 109916, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31733936

RESUMO

Methylparaben (MeP) is one of the most used preservatives in the industry; however, the toxic effects on aquatic ecosystems are still poorly understood. Therefore, this study was conducted (1) to identify and compare the toxic effects of MeP on physiological parameters of different green microalgae species, using suitable mathematical models; and (2) to estimate a PNEC value for MeP in freshwater ecosystems, adopting either the deterministic or the probabilistic approaches. Toxicity tests were carried out with three green microalgae (Pseudopediastrum boryanum, Desmodesmus communis, Raphidocelis subcapitata), in which different endpoints such as growth rate, chlorophyll-a, and cell viability were measured and compared through the effective concentration which caused a response in x% of test organisms (ECx). ECx were obtained by adjusting different non-linear regression models for each microalgae dataset. Chlorophyll-a endpoint resulted in the lowest EC50 values, respectively 125, 81.2, 18.3 mg L-1 for D. communis, P. boryanum and R. subcapitata, showing R. subicapitata as the most sensitive, and D. communis as the most tolerant species to MeP (P < 0.05). PNEC was estimated from the present study and previous reports resulting in 5.7 and 65 µg L-1, respectively for the deterministic (PNECd) and the probabilistic (PNECp) approach. The development of chronic assays using test organisms from different ecological groups is encouraged to provide robust PNECp. In this meantime, we recommend the use of the estimated PNECd to support MeP risk assessments and policy formulation.


Assuntos
Clorófitas/efeitos dos fármacos , Água Doce/química , Microalgas/efeitos dos fármacos , Parabenos/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Relação Dose-Resposta a Droga , Ecossistema , Modelos Teóricos , Dinâmica não Linear , Parabenos/análise , Testes de Toxicidade , Poluentes Químicos da Água/análise
13.
Sci Total Environ ; 702: 134803, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31731125

RESUMO

Photosynthetic picoeukaryotes (PPEs) are key players in aquatic systems, while their diversity and community composition dynamics remain poorly understood. The monthly composition of PPEs in Lake Chaohu was investigated using a combination of flow cytometry sorting and high throughput sequencing. Results indicated that temperature is the most important factor shaping PPEs community structure. The PPEs community can be categorized into three groups that are dominant at different temperature ranges: high temperature (>21.8 °C), intermediate temperature (between 9.8 °C and 21.8 °C) and low temperature (<9.8 °C). At the supergroup level, Cryptophyta were dominant at the intermediate temperature level, and Bacillariophyta were prevalent at low temperatures. In comparison, Chlorophyta PPEs were sensitive to temperature at the order level. Molecular network analysis using 18S rDNA sequencing results from sorted samples revealed that the Operational Taxonomic Units (OTUs) of PPE from the same taxonomic groups were predominantly positive, implying that they were occupying similar niches. The cooccurrence patterns between PPEs and fungi were mostly negative. In particular, OTU101, which was associated with Chytridiomycota, was negatively related to many OTUs belonging to Chlorophyta and Diatom, indicating that their potential parasitic associations may be not species-specific.


Assuntos
Lagos/microbiologia , Temperatura Ambiente , Microbiologia da Água , Clorófitas , Monitoramento Ambiental , Haptófitas , Fotossíntese
14.
Spectrochim Acta A Mol Biomol Spectrosc ; 224: 117382, 2020 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-31357053

RESUMO

Fourier transform infrared (FTIR) and Raman spectroscopic techniques were employed to analyze the biomolecular transitions and lipid accumulation in three freshwater green microalgal species, Monoraphidium contortum (M. contortum), Pseudomuriella sp. and Chlamydomonas sp. during various phases of their growth. Biomolecular transitions and lipid [hydrocarbons, triacylglycerides (TAGs)] accumulation within the microalgal cells were identified using second derivatives of the FTIR absorption spectroscopy. Second derivative analysis normalized and resolved the original spectra and led to the identification of smaller, overlapping bands. Both relative and absolute content of lipids were determined using the integrated band area. M. contortum exhibited higher accumulation of lipids than the other two species. The integrated band area of the vibrations from saturated (SFA) and unsaturated lipids (UFA) enabled quantification of fatty acids. The percentage of SFA and UFA was determined using GC, FTIR and Raman spectroscopy. From the spectral data, the order of increasing concentration of SFA among the three microalgal species was M. contortum > Chlamydomonas sp. >Pseudomuriella sp. The spectral results on fatty acids were consistent with the separation of lipids by gas chromatography. The results emphasized the significance of FTIR and Raman spectroscopic methods in monitoring the biomolecular transitions and rapid quantification of lipids, without the need for extraction of lipids.


Assuntos
Clorófitas , Lipídeos , Microalgas , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Análise Espectral Raman/métodos , Biocombustíveis/análise , Clorófitas/química , Clorófitas/metabolismo , Ácidos Graxos/análise , Ácidos Graxos/química , Ácidos Graxos/metabolismo , Lipídeos/análise , Lipídeos/química , Microalgas/química , Microalgas/metabolismo
15.
Carbohydr Polym ; 227: 115280, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31590855

RESUMO

A water-soluble polysaccharide from Monostroma nitidum, designated MWS, was isolated using water extraction, anion-exchange and size-exclusion chromatography. MWS was a sulfated glucuronorhamnan consisting of →3)-α-l-Rhap-(1→, →4)-ß-d-GlcpA-(1→ and →2)-α-l-Rhap-(1→ units. Sulfate ester groups located at C-4/C-2 of →3)-α-l-Rhap-(1→ and C-4/C-3 of →2)-α-l-Rhap-(1→ units. In in vitro tests, it was proved that MWS possessed broad spectrum against different viruses, especially for enterovirus 71 (EV71) with nearly no toxicity in relation to cell lines used. MWS may largely inhibit EV71 infection before or during viral adsorption through binding to virus particles and block some early steps of virus life cycle by down-regulating host phosphoinositide 3-kinase /protein kinase B signaling pathway. Intramuscular injection of MWS markedly reduced viral titers in EV71-infected mice. The data demonstrated that MWS could have great promising to become an antiviral drug for prevention and therapy of EV71 infection.


Assuntos
Antivirais/uso terapêutico , Clorófitas , Enterovirus Humano A/efeitos dos fármacos , Infecções por Enterovirus/tratamento farmacológico , Mananas/uso terapêutico , Sulfatos/uso terapêutico , Animais , Antivirais/química , Antivirais/farmacologia , Cães , Infecções por Enterovirus/virologia , Feminino , Células Madin Darby de Rim Canino , Mananas/química , Mananas/farmacologia , Camundongos Endogâmicos ICR , Estrutura Molecular , Alga Marinha , Sulfatos/química , Sulfatos/farmacologia , Células Vero
16.
Bioresour Technol ; 295: 122310, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31670114

RESUMO

The feasibility of substituting 50% nutrients by aqueous phase liquid (APL), derived from hydrothermal liquefaction of Tetraselmis sp. biomass, in a semi-continuous cultivation of Tetraselmis sp. was studied. Growth experiments were conducted in indoor photobioreactor and outdoor raceway tank for three consecutive cycles. At the end of exponential growth pahse, 75% of the culture was harvested, and the supernatant was returned to the cultivation system. For control cultures, fresh nutrients were added; however, for the experimental cultures, an appropriate volume of APL was added to replace half of the nutrients. Either indoor or outdoor, the growth rate and biomass yield in APL-added cultures were either equal or slightly better compared to control culture; although APL had little to no effect on the metabolite content of Tetraselmis sp., metabolites profile of Tetraselmis sp. varied between APL-added and control cultures. Nevertheless, 50% nutrients requirements for microalgae cultivation could be replaced by APL.


Assuntos
Clorófitas , Microalgas , Biomassa , Estudos de Viabilidade , Nutrientes , Temperatura Ambiente
17.
Environ Monit Assess ; 192(1): 8, 2019 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-31797148

RESUMO

Bisphenol-A (BPA) is a chemical used in the production of polycarbonate plastic and epoxy resins that may be related to the occurrence of human endocrine disorders. The present study aims to indicate a microalgae for use in ecotoxicological tests concerning BPA contamination of aquatic environments by analyzing its toxicity for the freshwater species Pseudokirchneriella subcapitata, and the two marine species Tetraselmis chuii and Skeletonema costatum. The standardization of the test involved determination of suitable nominal concentrations of BPA and the most appropriate species for use as biomarkers. S. costatum and P. subcapitata demonstrated resistance to BPA, features that are not of interest for toxicity markers. T. chuii presented an adequate sensitivity to BPA, compatible with parameters used in human toxicology for this substance, and is indicated as a potential biomarker for the presence of BPA in marine environments. The IC50 of T. chuii was 2.5 µM with R2 = 0.9, indicating reliability to demonstrate that low concentrations of BPA has significant toxicity to this species.


Assuntos
Compostos Benzidrílicos/toxicidade , Ecotoxicologia/métodos , Microalgas/efeitos dos fármacos , Fenóis/toxicidade , Poluentes Químicos da Água/toxicidade , Clorófitas/efeitos dos fármacos , Diatomáceas/efeitos dos fármacos , Água Doce/química , Reprodutibilidade dos Testes
18.
Environ Monit Assess ; 192(1): 38, 2019 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-31828435

RESUMO

Algae are a group of autotropic and eukaryotic organisms that play a significant role in the food, pharmaceutical, cosmetic, fuel, and textile industries. They are an important part of our ecosystem, and they can help control the growing problem of pollution. In this work, the carotenoid, sterol, polyphenol and mineral content, spectral and thermal characteristics of six common river algae, viz. Chara spp., Hydrodictyon spp., Lyngbya spp., Nitella spp., Pithophora spp., and Spirogyra spp., collected from Kharun river (India), were evaluated. The concentration of oil, total polyphenols, flavonoids, and mineral ranged from 0.4 to 4.3%, from 2705 to 4450 mg/kg, from 1590 to 2970 mg/kg, and from 85,466 to 122,871 mg/kg of algae (dw), respectively. The concentration of carotenoids and sterols varied from 1.6 to 109 mg/kg and from 522 to 35,664 mg/kg. The potentiality towards the bioaccumulation of 22 trace elements from the surface reservoir was assessed and discussed in relation to carbonate inlay of the algae wall and to the ions ability to bind to pectin, polypeptides, carotenoids, polyphenols, and flavonoids, on the basis of infrared spectroscopy data. In view of the extremely high enrichment factors found for certain elements, such as P, Co, Cu, Pb, and Fe, some of these algae hold promise as bioindicators for the detection of these elements in aquatic environments. Ordination analysis was used to measure the variance gradient of the algal data.


Assuntos
Clorófitas/metabolismo , Monitoramento Ambiental , Oligoelementos/metabolismo , Poluentes Químicos da Água/metabolismo , Bioacumulação , Ecossistema , Índia , Rios/química , Oligoelementos/análise , Poluentes Químicos da Água/análise , Poluição da Água/análise
19.
Pol J Microbiol ; 68(4): 527-539, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31880896

RESUMO

Ulleungdo and Dokdo are volcanic islands with an oceanic climate located off the eastern coast of South Korea. In the present study, we used barcoded Illumina MiSeq to analyze eukaryotic microalgal genera collected from Seonginbong, the highest peak on Ulleungdo, and from groundwater sites on Dongdo and Seodo Islands, which are part of Dokdo. Species richness was significantly greater in the Seonginbong samples than in the Dongdo and Seodo samples, with 834 operational taxonomic units (OTUs) identified from Seonginbong compared with 203 OTUs and 182 OTUs from Dongdo and Seodo, respectively. Taxonomic composition analysis was also used to identify the dominant microalgal phyla at each of the three sites, with Chlorophyta (green algae) the most abundant phyla on Seonginbong and Dongdo, and Bacillariophyta (diatoms) the most abundant on Seodo. These findings suggest that differences in the abundances of Chlorophyta and Bacillariophyta species in the Seonginbong, Dongdo, and Seodo samples are due to variations in species richness and freshwater resources at each sampling location. To the best of our knowledge, this is the first report to detail freshwater microalgal communities on Ulleungdo and Dokdo. As such, the number of species identified in the Seonginbong, Dongdo, and Seodo samples might be an indicator of the ecological differences among these sites and varying characteristics of their microbial communities. Information regarding the microalgal communities also provides a basis for understanding the ecological interactions between microalgae species and other eukaryotic microorganisms.Ulleungdo and Dokdo are volcanic islands with an oceanic climate located off the eastern coast of South Korea. In the present study, we used barcoded Illumina MiSeq to analyze eukaryotic microalgal genera collected from Seonginbong, the highest peak on Ulleungdo, and from groundwater sites on Dongdo and Seodo Islands, which are part of Dokdo. Species richness was significantly greater in the Seonginbong samples than in the Dongdo and Seodo samples, with 834 operational taxonomic units (OTUs) identified from Seonginbong compared with 203 OTUs and 182 OTUs from Dongdo and Seodo, respectively. Taxonomic composition analysis was also used to identify the dominant microalgal phyla at each of the three sites, with Chlorophyta (green algae) the most abundant phyla on Seonginbong and Dongdo, and Bacillariophyta (diatoms) the most abundant on Seodo. These findings suggest that differences in the abundances of Chlorophyta and Bacillariophyta species in the Seonginbong, Dongdo, and Seodo samples are due to variations in species richness and freshwater resources at each sampling location. To the best of our knowledge, this is the first report to detail freshwater microalgal communities on Ulleungdo and Dokdo. As such, the number of species identified in the Seonginbong, Dongdo, and Seodo samples might be an indicator of the ecological differences among these sites and varying characteristics of their microbial communities. Information regarding the microalgal communities also provides a basis for understanding the ecological interactions between microalgae species and other eukaryotic microorganisms.


Assuntos
Microalgas/isolamento & purificação , Clorófitas/classificação , Clorófitas/genética , Diatomáceas/classificação , Diatomáceas/genética , Diatomáceas/isolamento & purificação , Água Doce/análise , Ilhas , Microalgas/classificação , Microalgas/genética , Filogenia , Análise de Sequência de DNA
20.
PLoS One ; 14(12): e0220422, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31841562

RESUMO

Benthic cyanobacterial proliferations in rivers are have been reported with increasing frequency worldwide. In the Eel and Russian rivers of California, more than a dozen dog deaths have been attributed to cyanotoxin toxicosis since 2000. Periphyton proliferations in these rivers comprise multiple cyanobacterial taxa capable of cyanotoxin production, hence there is uncertainty regarding which taxa are producing toxins. In this study, periphyton samples dominated by the cyanobacterial genera Anabaena spp. and Microcoleus spp. and the green alga Cladophora glomerata were collected from four sites in the Eel River catchment and one site in the Russian River. Samples were analysed for potential cyanotoxin producers using polymerase chain reaction (PCR) in concert with Sanger sequencing. Cyanotoxin concentrations were measured using liquid chromatography tandem-mass spectrometry, and anatoxin quota (the amount of cyanobacterial anatoxins per toxigenic cell) determined using droplet digital PCR. Sequencing indicated Microcoleus sp. and Nodularia sp. were the putative producers of cyanobacterial anatoxins and nodularins, respectively, regardless of the dominant taxa in the mat. Anatoxin concentrations in the mat samples varied from 0.1 to 18.6 µg g-1 and were significantly different among sites (p < 0.01, Wilcoxon test); however, anatoxin quotas were less variable (< 5-fold). Dihydroanatoxin-a was generally the most abundant variant in samples comprising 38% to 71% of the total anatoxins measured. Mats dominated by the green alga C. glomerata contained both anatoxins and nodularin-R at concentrations similar to those of cyanobacteria-dominated mats. This highlights that even when cyanobacteria are not the dominant taxa in periphyton, these mats may still pose a serious health risk and indicates that more widespread monitoring of all mats in a river are necessary.


Assuntos
Toxinas Bacterianas/análise , Cianobactérias/patogenicidade , Rios/química , Anabaena/patogenicidade , California , Clorófitas/genética , Clorófitas/metabolismo , Cromatografia Líquida , Cianobactérias/genética , Cianobactérias/metabolismo , Reação em Cadeia da Polimerase , Prolina/análogos & derivados , Prolina/análise , Microbiologia da Água
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