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1.
Molecules ; 26(8)2021 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-33917694

RESUMO

The recently emerged COVID-19 disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has adversely affected the whole world. As a significant public health threat, it has spread worldwide. Scientists and global health experts are collaborating to find and execute speedy diagnostics, robust and highly effective vaccines, and therapeutic techniques to tackle COVID-19. The ocean is an immense source of biologically active molecules and/or compounds with antiviral-associated biopharmaceutical and immunostimulatory attributes. Some specific algae-derived molecules can be used to produce antibodies and vaccines to treat the COVID-19 disease. Algae have successfully synthesized several metabolites as natural defense compounds that enable them to survive under extreme environments. Several algae-derived bioactive molecules and/or compounds can be used against many diseases, including microbial and viral infections. Moreover, some algae species can also improve immunity and suppress human viral activity. Therefore, they may be recommended for use as a preventive remedy against COVID-19. Considering the above critiques and unique attributes, herein, we aimed to systematically assess algae-derived, biologically active molecules that could be used against this disease by looking at their natural sources, mechanisms of action, and prior pharmacological uses. This review also serves as a starting point for this research area to accelerate the establishment of anti-SARS-CoV-2 bioproducts.


Assuntos
Antivirais/uso terapêutico , Clorófitas/química , Feófitas/química , Rodófitas/química , Antivirais/química , Antivirais/isolamento & purificação , /virologia , Carragenina/química , Carragenina/isolamento & purificação , Carragenina/uso terapêutico , Clorófitas/metabolismo , Humanos , Lectinas/isolamento & purificação , Lectinas/uso terapêutico , Feófitas/metabolismo , Polissacarídeos/isolamento & purificação , Polissacarídeos/uso terapêutico , Rodófitas/metabolismo , /isolamento & purificação
2.
Bioresour Technol ; 332: 125121, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33845314

RESUMO

Currently, there is a lack of an efficient, environmentally-benign and sustainable industrial decontamination strategy to steadily achieve improved astaxanthin production from Haematococcus pluvialis under large-scale outdoor conditions. Here, this study demonstrates for the first time that a CaCO3 biomineralization-based decontamination strategy (CBDS) is highly efficient in selectively eliminating algicidal microorganisms, such as bacteria and fungi, during large-scale H. pluvialis cultivation under autotrophic and mixotrophic conditions, thereby augmenting the astaxanthin productivity. Under outdoor AT and MT conditions, the average astaxanthin productivity of H. pluvialis using CBDS in a closed photobioreactor system was substantially increased by 14.85- (1.19 mg L-1 d-1) and 13.65-fold (2.43 mg L-1 d-1), respectively, compared to the contaminated H. pluvialis cultures. Given the exponentially increasing demand of astaxanthin, a natural anti-viral, anti-inflammatory, and antioxidant drug, CBDS will be a technology of interest in H. pluvialis-based commercial astaxanthin production which has been hindered by the serious biological contaminations.


Assuntos
Clorófitas , Biomassa , Biomineralização , Descontaminação , Xantofilas
3.
Bioresour Technol ; 332: 125150, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33878543

RESUMO

Astaxanthin is a valuable and highly demanded ketocarotenoid pigment, for which the chlorophycean microalga Haematococcus pluvialis is an outstanding natural source. Although information on astaxanthin accumulation in H. pluvialis has substantially advanced in recent years, its underlying molecular bases remain elusive. An integrative metabolic and transcriptomic analysis has been performed for vegetative Haematococcus cells, grown both under N sufficiency (green palmelloid cells) and under moderate N limitation, allowing concurrent active cell growth and astaxanthin synthesis (reddish palmelloid cells). Transcriptional activation was noticeable in reddish cells of key enzymes participating in glycolysis, pentose phosphate cycle and pyruvate metabolism, determining the adequate provision of glyceraldehyde 3 phosphate and pyruvate, precursors of carotenoids and fatty acids. Moreover, for the first time, transcriptional regulators potentially involved in controlling astaxanthin accumulation have been identified, a knowledge enabling optimization of commercial astaxanthin production by Haematococcus through systems metabolic engineering.


Assuntos
Clorofíceas , Clorófitas , Clorófitas/genética , Transcriptoma , Xantofilas
4.
Artigo em Inglês | MEDLINE | ID: mdl-33807417

RESUMO

In the present study we investigated the ability of the microalgal strain Parachlorella sp. AA1 to biologically uptake a radionuclide waste material. Batch experiments were conducted to investigate the biosorption of uranyl ions (U(VI)) in the 0.5-50.0 mg/L concentration range by strain AA1. The results showed that AA1 biomass could uptake U(VI). The highest removal efficiency and biosorption capacity (95.6%) occurred within 60 h at an initial U(VI) concentration of 20 mg/L. The optimum pH for biosorption was 9.0 at a temperature of 25 °C. X-ray absorption near edge structure analysis confirmed the presence of U(VI) in pellets of Parachlorella sp. AA1 cells. The biosorption methods investigated here may be useful in the treatment and disposal of nuclides and heavy metals in diverse wastewaters.


Assuntos
Clorófitas , Poluentes Químicos da Água , Adsorção , Biomassa , Concentração de Íons de Hidrogênio , Íons , Cinética
5.
Huan Jing Ke Xue ; 42(2): 808-818, 2021 Feb 08.
Artigo em Chinês | MEDLINE | ID: mdl-33742875

RESUMO

In the fields of phytoplankton ecology, water optics, and water color remote sensing, phytoplankton absorption properties represent the light absorption capacity of phytoplankton, which affects photosynthesis efficiency and carbon fixation. Here, the biomass, community composition, and the absorption properties of phytoplankton were measured alongside other bio-optical parameters in Lake Tianmu are examined using data collected between January and November 2013 (except February). Based on the relationships between phytoplankton biomass, community composition, and absorption, the effects of abundance, biomass, and equivalent sphere diameter on phytoplankton absorption and specific absorption were revealed. The highest biomass and abundance of phytoplankton were recorded in the autumn and the lowest in the winter. Cryptomonas, Synedra, and Cyclotella were the dominant genera throughout the year. The dominant genera structure type was Bacillariophyta-Cryptophyta in the winter and spring, Bacillariophyta-Chlorophyta-Pyrroptata in the summer, and Cryptophyta-Bacillariophyta-Chlorophyta in the autumn. Phytoplankton diameter was ranked in the order summer>autumn>winter>spring, with mean values of 64.83 µm in summer and 29.54 µm in spring. Phytoplankton absorption coefficients of were ranked in the order autumn > spring > winter > summer, with mean values at 440 nm and 675 nm of (0.66±0.18) m-1 and (0.33±0.10) m-1 in autumn and (0.17±0.02) m-1 and (0.08±0.01) m-1 in summer, respectively. The specific absorption coefficients of the phytoplankton were ranked in the order spring > winter > autumn > summer, with mean values at 440 nm and 675 nm of (0.07±0.02) m2·mg-1 and (0.04±0.01) m2·mg-1 in spring and (0.03±0.004) m2·mg-1 and (0.01±0.002) m2·mg-1 in summer, respectively. Significant linear correlations were found between phytoplankton biomass, abundance, and absorption coefficients. Variations of Bacillariophyta and Cyanophyta biomass caused by temperature explained the seasonal variation in absorption coefficients. The specific absorption coefficient decreased with an increase in equivalent sphere diameter, and variations in phytoplankton community composition explained seasonal changes in the specific absorption coefficient.


Assuntos
Clorófitas , Cianobactérias , Diatomáceas , China , Lagos , Fitoplâncton , Estações do Ano
6.
Int J Mol Sci ; 22(4)2021 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-33672866

RESUMO

Parkinsons Disease (PD) is the second most common neurodegenerative disease worldwide, and is characterized by a progressive degeneration of dopaminergic neurons. Without an effective treatment, it is crucial to find new therapeutic options to fight the neurodegenerative process, which may arise from marine resources. Accordingly, the goal of the present work was to evaluate the ability of the monoterpenoid lactone Loliolide, isolated from the green seaweed Codium tomentosum, to prevent neurological cell death mediated by the neurotoxin 6-hydroxydopamine (6-OHDA) on SH-SY5Y cells and their anti-inflammatory effects in RAW 264.7 macrophages. Loliolide was obtained from the diethyl ether extract, purified through column chromatography and identified by NMR spectroscopy. The neuroprotective effects were evaluated by the MTT method. Cells' exposure to 6-OHDA in the presence of Loliolide led to an increase of cells' viability in 40%, and this effect was mediated by mitochondrial protection, reduction of oxidative stress condition and apoptosis, and inhibition of the NF-kB pathway. Additionally, Loliolide also suppressed nitric oxide production and inhibited the production of TNF-α and IL-6 pro-inflammatory cytokines. The results suggest that Loliolide can inspire the development of new neuroprotective therapeutic agents and thus, more detailed studies should be considered to validate its pharmacological potential.


Assuntos
Anti-Inflamatórios/farmacologia , Benzofuranos/farmacologia , Clorófitas/química , Lactonas/farmacologia , Monoterpenos/farmacologia , Doenças Neurodegenerativas/tratamento farmacológico , Animais , Anti-Inflamatórios/química , Benzofuranos/química , Linhagem Celular Tumoral , Citocinas/metabolismo , Fragmentação do DNA/efeitos dos fármacos , Humanos , Lactonas/química , Macrófagos/citologia , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Camundongos , Estrutura Molecular , Monoterpenos/química , NF-kappa B/metabolismo , Fármacos Neuroprotetores/química , Fármacos Neuroprotetores/farmacologia , Óxido Nítrico/metabolismo , Células RAW 264.7 , Espécies Reativas de Oxigênio/metabolismo
7.
Carbohydr Polym ; 261: 117881, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33766368

RESUMO

Marine green algae biomass residue (ABR), a waste by-product of Dunaliella tertiolecta, left behind after the extraction of oil from the algal biomass, was utilized for the fabrication of cellulose nanocrystals (CNCs). The fabricated sulphuric acid hydrolysed CNCs had needle-like morphology, with dominant cellulose type I polymorph and a high crystallinity index of 89 %. ICP-MS elemental analysis confirmed the presence of a variety of minerals in the ABR. Washed ABR (WABR)/PLA and CNC/PLA bio-composite films were developed via solvent casting technique with varying bio-filler loadings for comparing their effectiveness on the crystallization behaviour of PLA. FESEM, FTIR, XRD and TGA were used to characterize the bio-fillers. The nucleating and crystallization behaviour of the bio-composite films were confirmed using DSC, SAXS and POM analysis which indicated better effectiveness of CNCs with a significant reduction in cold crystallization temperature, and noteworthy increment in crystallinity and spherulite growth rate.


Assuntos
Celulose/isolamento & purificação , Clorófitas/química , Nanopartículas , Poliésteres/química , Biomassa , Celulose/química , Celulose/farmacologia , Precipitação Química/efeitos dos fármacos , Clorófitas/metabolismo , Cristalização , Nanopartículas/química , Nanopartículas/metabolismo , Espalhamento a Baixo Ângulo , Difração de Raios X
8.
Adv Exp Med Biol ; 1261: 3-10, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33783726

RESUMO

This is an overview of the potential of Haematococcus pluvialis for use in the commercial production of natural astaxanthin, along with a survey of mass culture methods that utilize the characteristics of H. pluvialis. The latest advancements in cultivation methods that incorporate new technologies, such as light-emitting diodes (LEDs), are outlined. Furthermore, the differences in culture conditions that may affect the product quality required to meet the standards for its use as a health supplement ingredient are discussed. Additionally, insights are provided on some of the current avenues of research and the future of astaxanthin cultivation.


Assuntos
Clorófitas , Luz , Xantofilas
9.
Aquat Toxicol ; 233: 105774, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33610856

RESUMO

Polychlorinated naphthalenes (PCNs) are widely distributed in the aquatic environment and can be transmitted through the food chain, which can amplify their toxic effects on human. To inhibit their transmission in the trophic level, this study aimed to predict the joint toxicity mechanism of polychlorinated naphthalenes (PCNs) to the key organisms and control scheme of its toxicity in the aquatic food chain (green algae-Daphnia magna-fish). The toxic effect grade and mode of action (MoA) of PCNs on the food chain were first predicted to guide the establishment of toxic mechanism model. QSAR models were constructed to quantify the mechanism of aquatic toxicity due to PCNs. The results showed the PCN compounds studied were highly toxic at all the trophic levels of the aquatic food chain. The binding ability of PCNs to the aquatic organisms was the main factor causing the toxicity of PCNs in the food chain, followed by electronic parameters EHOMO and ELUMO. Moreover, the binding ability between PCNs and food chain receptors was related to the molecular hydrophobicity, the hydrophobicity can be changed by adjusting the ability of PCNs to be adsorbed by sediment and their chlorine substituents, while the effect of PCNs electronic parameters (EHOMO and ELUMO) can be adjusted by their solvation effect. In addition, the macro-control scheme of PCN-based aquatic toxicity mechanism was established, and the molecular dynamics (MD) simulation confirmed its effectiveness and accessibility. The MD simulation showed the inhibition effect of nutrition-grade toxicity in the food chain was significant when the external stimulation conditions of solvation, anaerobic dechlorination and molecular adsorption were improved, with the decrease range of 66.26-263.16%, 198.93-323.98% and 189.24-549.48%, respectively. This work reveals new insights into the mechanism of PCNs joint toxicity to aquatic ecosystem food chain and develop appropriate strategies for its ecological risk management.


Assuntos
Organismos Aquáticos/metabolismo , Hidrocarbonetos Clorados/toxicidade , Naftalenos/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Clorófitas/metabolismo , Daphnia/metabolismo , Ecossistema , Ecotoxicologia , Peixes/metabolismo , Cadeia Alimentar , Humanos
10.
Environ Pollut ; 276: 116695, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33601201

RESUMO

Daunting amounts of microplastics are present in surface waters worldwide. A main category of microplastics is synthetic microfibers, which originate from textiles. These microplastics are generated and released in laundering and are discharged by wastewater treatment plants or enter surface waters from other sources. The polymers that constitute many common synthetic microfibers are mostly denser than water, and eventually settle out in aquatic environments. The interaction of these microfibers with submerged aquatic vegetation has not been thoroughly investigated but is potentially an important aquatic sink in surface waters. In the Laurentian Great Lakes, prolific growth of macrophytic Cladophora creates submerged biomass with a large amount of surface area and the potential to collect and concentrate microplastics. To determine the number of synthetic microfibers in Great Lakes Cladophora, samples were collected from Lakes Erie and Michigan at multiple depths in the spring and summer of 2018. After rinsing and processing the algae, associated synthetic microfibers were quantified. The average loads of synthetic microfibers determined from the Lake Erie and Lake Michigan samples were 32,000 per kg (dry weight (dw)) and 34,000 per kg (dw), respectively, 2-4 orders of magnitude greater than loads previously reported in water and sediment. To further explore this sequestration of microplastics, fresh and aged Cladophora were mixed with aqueous mixtures of microfibers or microplastic in the laboratory to simulate pollution events. Microscopic analyses indicated that fresh Cladophora algae readily interacted with microplastics via adsorptive forces and physical entanglement. These interactions mostly cease upon algal senescence, with an expected release of microplastics in benthic sediments. Collectively, these findings suggest that synthetic microfibers are widespread in Cladophora algae and the affinity between microplastics and Cladophora may offer insights for removing microplastic pollution. Macroalgae in the Laurentian Great Lakes contain high loads of synthetic microfibers, both entangled and adsorbed, which likely account for an important fraction of microplastics in these surface waters.


Assuntos
Clorófitas , Poluentes Químicos da Água , Monitoramento Ambiental , Lagos , Michigan , Microplásticos , Plásticos , Poluentes Químicos da Água/análise
11.
Plant Mol Biol ; 105(4-5): 497-511, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33415608

RESUMO

KEY MESSAGE: The study shows the biochemical and enzymatic divergence between the two aldehyde-alcohol dehydrogenases of the alga Polytomella sp., shedding light on novel aspects of the enzyme evolution amid unicellular eukaryotes. Aldehyde-alcohol dehydrogenases (ADHEs) are large metalloenzymes that typically perform the two-step reduction of acetyl-CoA into ethanol. These enzymes consist of an N-terminal acetylating aldehyde dehydrogenase domain (ALDH) and a C-terminal alcohol dehydrogenase (ADH) domain. ADHEs are present in various bacterial phyla as well as in some unicellular eukaryotes. Here we focus on ADHEs in microalgae, a diverse and polyphyletic group of plastid-bearing unicellular eukaryotes. Genome survey shows the uneven distribution of the ADHE gene among free-living algae, and the presence of two distinct genes in various species. We show that the non-photosynthetic Chlorophyte alga Polytomella sp. SAG 198.80 harbors two genes for ADHE-like enzymes with divergent C-terminal ADH domains. Immunoblots indicate that both ADHEs accumulate in Polytomella cells growing aerobically on acetate or ethanol. ADHE1 of ~ 105-kDa is found in particulate fractions, whereas ADHE2 of ~ 95-kDa is mostly soluble. The study of the recombinant enzymes revealed that ADHE1 has both the ALDH and ADH activities, while ADHE2 has only the ALDH activity. Phylogeny shows that the divergence occurred close to the root of the Polytomella genus within a clade formed by the majority of the Chlorophyte ADHE sequences, next to the cyanobacterial clade. The potential diversification of function in Polytomella spp. unveiled here likely took place after the loss of photosynthesis. Overall, our study provides a glimpse at the complex evolutionary history of the ADHE in microalgae which includes (i) acquisition via different gene donors, (ii) gene duplication and (iii) independent evolution of one of the two enzymatic domains.


Assuntos
Álcool Desidrogenase/genética , Aldeído Desidrogenase/genética , Clorófitas/genética , Variação Genética , Microalgas/genética , Filogenia , Álcool Desidrogenase/classificação , Álcool Desidrogenase/metabolismo , Aldeído Desidrogenase/classificação , Aldeído Desidrogenase/metabolismo , Proteínas de Algas/genética , Proteínas de Algas/metabolismo , Sequência de Aminoácidos , Clorófitas/enzimologia , Espectrometria de Massas/métodos , Microalgas/enzimologia , Proteômica/métodos , Análise de Sequência de DNA/métodos , Homologia de Sequência de Aminoácidos
12.
J Phycol ; 57(2): 435-446, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33394518

RESUMO

In the Arctic Ocean, the small green alga Micromonas polaris dominates picophytoplankton during the summer months but is also present in winter. It has been previously hypothesized to be phago-mixotrophic (capable of bacteria ingestion) based on laboratory and field experiments. Prey uptake was analyzed in several M. polaris strains isolated from different regions and depths of the Arctic Ocean and in Ochromonas triangulata, a known phago-mixotroph used as a control. Measuring ingestion of either fluorescent beads or fluorescently labeled bacteria by flow cytometry, we found no evidence of phago-mixotrophy in any M. polaris strain while O. triangulata was ingesting both beads and bacteria. In addition, in silico predictions revealed that members of the genus Micromonas lack a genetic signature of phagocytotic capacity.


Assuntos
Clorófitas , Regiões Árticas , Bactérias , Estações do Ano
13.
J Phycol ; 57(2): 447-453, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33450042

RESUMO

There is little information available regarding genomic differences between sexes in ulvophycean green algae. The detection of these differences will enable the development of sex-discriminating molecular markers, which are useful for algae showing little apparent difference between sexes. In this study, we identified male- and female-specific DNA sequences in the ulvophycean marine green alga Monostroma angicava, which has a dioicous heteromorphic haplo-diplontic life cycle, via next-generation sequencing. Fluorescence in situ hybridization (FISH) showed that signals for the sex-specific sequences exist only in the nuclei of the corresponding sex, confirming the specificity of the sequences. Sex-specific molecular markers that targeted these sequences successfully distinguished the sex of gametophytes even in geographically distant populations, indicating that the sex-specific sequences are universal. These results consistently suggest that male and female gametophytes of M. angicava are genetically different, implying that sex may be determined genetically in this alga.


Assuntos
Clorófitas , Genoma , Clorófitas/genética , DNA , Feminino , Genômica , Hibridização in Situ Fluorescente , Masculino
14.
BMC Ecol Evol ; 21(1): 11, 2021 01 25.
Artigo em Inglês | MEDLINE | ID: mdl-33514317

RESUMO

BACKGROUND: Pyrenoids are protein microcompartments composed mainly of Rubisco that are localized in the chloroplasts of many photosynthetic organisms. Pyrenoids contribute to the CO2-concentrating mechanism. This organelle has been lost many times during algal/plant evolution, including with the origin of land plants. The molecular basis of the evolutionary loss of pyrenoids is a major topic in evolutionary biology. Recently, it was hypothesized that pyrenoid formation is controlled by the hydrophobicity of the two helices on the surface of the Rubisco small subunit (RBCS), but the relationship between hydrophobicity and pyrenoid loss during the evolution of closely related algal/plant lineages has not been examined. Here, we focused on, the Reticulata group of the unicellular green algal genus Chloromonas, within which pyrenoids are present in some species, although they are absent in the closely related species. RESULTS: Based on de novo transcriptome analysis and Sanger sequencing of cloned reverse transcription-polymerase chain reaction products, rbcS sequences were determined from 11 strains of two pyrenoid-lacking and three pyrenoid-containing species of the Reticulata group. We found that the hydrophobicity of the RBCS helices was roughly correlated with the presence or absence of pyrenoids within the Reticulata group and that a decrease in the hydrophobicity of the RBCS helices may have primarily caused pyrenoid loss during the evolution of this group. CONCLUSIONS: Although we suggest that the observed correlation may only exist for the Reticulata group, this is still an interesting study that provides novel insight into a potential mechanism determining initial evolutionary steps of gain and loss of the pyrenoid.


Assuntos
Clorófitas , Ribulose-Bifosfato Carboxilase , Carbono , Clorófitas/genética , Eucariotos , Plastídeos , Ribulose-Bifosfato Carboxilase/genética
15.
Extremophiles ; 25(2): 129-141, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33475805

RESUMO

For mass culture of photosynthetic green microalgae, industrial flue gases can represent a low-cost resource of CO2. However, flue gases are often avoided, because they often also contain high levels of SO2 and/or NO2, which cause significant acidification of media to below pH 3 due to production of sulfuric and nitric acid. This creates an unsuitable environment for the neutrophilic microalgae commonly used in large-scale commercial production. To address this issue, we have looked at selecting acid-tolerant microalgae via growth at pH 2.5 carried out with samples bioprospected from an active smelter site. Of the eight wild samples collected, one consisting mainly of Coccomyxa sp. grew at pH 2.5 and achieved a density of 640 mg L-1. Furthermore, three previously bioprospected green microalgae from acidic waters (pH 3-4.5) near abandoned mine sites were also re-acclimated down to their in-situ pH environment after approximately 4 years spent at neutral pH. Of those three, an axenic culture of Coccomyxa sp. was the most successful at re-acclimating and achieved the highest density of 293.1 mg L-1 and maximum daily productivity of 38.8 mg L-1 day-1 at pH 3. Re-acclimation of acid-tolerant species is, therefore, achievable when directly placed at their original pH, but gradual reduction in pH is recommended to give the cells time to acclimate.


Assuntos
Clorófitas , Microalgas , Aclimatação , Biomassa , Dióxido de Carbono , Gases , Concentração de Íons de Hidrogênio
16.
Ecotoxicol Environ Saf ; 208: 111630, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396150

RESUMO

The non-steroidal anti-inflammatory drug diclofenac (DCF) is one of the commonly used and frequently detected drugs in water bodies, and several studies indicate its toxic effect on plants and algae. Studies performed with asynchronous Chlamydomonas reinhardtii cultures indicated that DCF inhibit the growth of population of the algae. Here, a synchronous population of C. reinhardtii, in which all cells are in the same developmental phase, is used. Following changes in cells size, photosynthetic activity and gene expression, we could compare, at the level of single cell, DCF-mediated effects with the effects caused by atrazine, a triazine herbicide that inhibits photosynthesis and triggers oxidative stress. Application of DCF and atrazine at the beginning of the cell cycle allowed us to follow the changes occurring in the cells in the subsequent stages of their development. Synchronized Chlamydomonas reinhardtii cultures (strain CC-1690, wild type) were exposed to diclofenac sodium salt (135 mg/L) or atrazine (77.6 µg/L). The cell suspension was sampled hourly (0-10 h) in the light period of the cell cycle to determine cell number and volume, photosynthetic pigment content, chlorophyll a fluorescence (OJIP test) in vivo, and selected gene expression (real-time qPCR), namely psbA, psaA, FSD1, MSD3 and APX1. The two toxicants differently influenced C. reinhardtii cells. Both substances decreased photosynthetic "vitality" (PI - performance index) of the cells, albeit for different reasons. While atrazine significantly disrupted the photosynthetic electron transport, resulting in excessive production of reactive oxygen species (ROS) and limited cell growth, DCF caused silencing of photosystem II (PSII) reaction centers, transforming them into "heat sinks", thus preventing significant ROS overproduction. Oxidative stress caused by atrazine was the probable reason for the rapid appearance of phytotoxic action soon after entering the cells, while the effects of DCF could only be seen several hours after treatment. A comparison of DCF-caused effects with the effects caused by atrazine led us to conclude that, although DCF cannot be regarded as typical photosynthetic herbicide, it exhibits an algicidal activity and can be potentially dangerous for aquatic plants and algae.


Assuntos
Chlamydomonas reinhardtii/fisiologia , Diclofenaco/toxicidade , Herbicidas/toxicidade , Fotossíntese/efeitos dos fármacos , Atrazina/metabolismo , Atrazina/toxicidade , Chlamydomonas reinhardtii/efeitos dos fármacos , Clorofila A/metabolismo , Clorófitas/metabolismo , Diclofenaco/metabolismo , Transporte de Elétrons/efeitos dos fármacos , Herbicidas/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Complexo de Proteína do Fotossistema II/metabolismo , Espécies Reativas de Oxigênio/metabolismo
17.
J Plant Res ; 134(1): 77-89, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33387091

RESUMO

Some algae are known to grow on shellfish shells. Most of these have been reported in aquatic environments. The species specificity for substrate shells varies, and some algae grow only on the shells of a certain species of shellfish, such as Pseudocladophora conchopheria (Cladophorales, Ulvophyceae) on Lunella coreensis (Trochida, Gastropoda). There are very few reports of algae that grow on land snails. In this study, we discovered green algae growing on the shells of six species of door snails (Clausiliidae) from nine localities in Japan. These green algae formed a green mat composed of thalli embedded in the extracellular matrix. The thallus was composed of aggregated oval cells and peripheral branched filaments. The cells possessed a single parietal chloroplast with a pyrenoid surrounded by two starch sheaths and transversed by a thylakoid. Oil droplets in the cell and ring-like structures on the cell wall surface were frequently observed. The 18S rDNA sequences of all shell-attached algae on different clausiliid species from different localities were almost identical and formed a new clade in the family Kornmanniaceae (Ulvales, Ulvophyceae). No other algae forming visible colonies on the clausiliid shell were found. These findings indicate the presence of specificity between the alga and clausiliid shells. Based on the results of morphological observation and molecular phylogenetic analysis, we propose a new genus and new species of shell-attached green alga, Annulotesta cochlephila.


Assuntos
Clorófitas , Animais , Clorófitas/genética , DNA Ribossômico/genética , Japão , Filogenia , Caramujos
18.
Bioresour Technol ; 326: 124761, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33503516

RESUMO

High-strength organic wastewater, e.g., potato juice wastewater, exerts high stress on the environment. This study proposes an integrated system for simultaneous high-strength organic wastewater treatment and nutrients upcycling for astaxanthin production by the combination of anaerobic processes and microalgae (Haematococcus pluvialis) cultivation. The potato juice wastewater was pretreated by either acidification or methanation. The effluents of both pretreatments achieved higher biomass yields of H. pluvialis compared to cultivation in standard culture media (control). The high acetate and potassium concentrations of the acidification effluents resulted in significantly higher astaxanthin production (24.5-27.9 mg g-1, 3 days) compared to the control (14.7 mg g-1, 12 days) in a shorter period. The integrated system contributed to a final removal efficiency of 51.3-75.8%, 86.5-98.3%, and 69.4-83.4% for COD, phosphorus, and ammonia, respectively. This study presents a promising two-stage process for simultaneous efficient methane and astaxanthin production, as well as remediation of high-strength organic wastewater.


Assuntos
Clorófitas , Purificação da Água , Xantofilas
19.
Aquat Toxicol ; 231: 105732, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33385847

RESUMO

River biofilms are a suitable indicator of toxic stress in aquatic ecosystems commonly exposed to various anthropogenic pollutants from industrial, domestic, and agricultural sources. Among these pollutants, heavy metals are of particular concern as they are known to interfere with various physiological processes of river biofilm, directly or indirectly related to photosynthetic performance. Nevertheless, only limited toxicological data are available on the mechanisms and toxicodynamics of heavy metals in biofilms. Pulse Amplitude Modulated (PAM) fluorometry is a rapid, non-disruptive, well-established technique to monitor toxic responses on photosynthetic performance, fluorescence-kinetics, and changes in yield in other non-photochemical processes. In this study, a new micro-PAM-sensor was tested to assess potential acute and chronic effects of heavy metals in river biofilm. Toxicity values across the three parameters considered in this study (photosynthetic yield YII, non-photochemical quenching NPQ, and basal fluorescence F0) were comparable, as determined EC50 were within one order of magnitude (EC50 ∼1-10 mg L-1). However, the stimulation of NPQ was more clearly associated with early acute effects, especially in illuminated samples, while depression of YII and F0 were more prevalent in chronic tests. These results have implications for the development of functional indicators for the biomonitoring of aquatic health, in particular for the use of river biofilm as a bioindicator of water quality. In conclusion, the approach proposed seems promising to characterize and monitor the exposure and impact of heavy metals on river periphyton communities. Furthermore, this study provides a fast, highly sensitive, inexpensive, and accurate laboratory method to test effects of pollutants on complex periphyton communities that can also give insights regarding the probable toxicological mechanisms of heavy metals on photosynthetic performance in the river biofilm.


Assuntos
Técnicas Biossensoriais , Exposição Ambiental , Fluorometria/instrumentação , Metais Pesados/toxicidade , Rios/química , Biofilmes/efeitos dos fármacos , Clorófitas/citologia , Clorófitas/efeitos dos fármacos , Diatomáceas/citologia , Diatomáceas/efeitos dos fármacos , Monitoramento Ambiental , Fluorescência , Perifíton/efeitos dos fármacos , Processos Fotoquímicos , Fotossíntese/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Poluição da Água/análise , Qualidade da Água
20.
Carbohydr Polym ; 254: 117252, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33357848

RESUMO

The green alga Parachlorella sp. BX1.5 is a new strain that can significantly coproduce lipids and polysaccharides, inside and outside the cells, respectively. This study aimed to investigate the characteristics and functional properties of the extracellular polysaccharide (EPS). Ethanol-extracted EPS from the cells grown in N-starved BG11 medium was found to be a novel acidic rhamnan of straight-chain type, with a high molecular mass of > 1.75 × 106 daltons. The water-soluble EPS exhibited high viscosity as sol, even at low concentrations, with 0.5 % EPS showing almost constant viscosity at 10-40 °C. Its addition to mayonnaise resulted in improved oil-off, suggesting its possible application as a thickener or food additive. Cells with added EPS were found to exhibit resistance to environmental stress conditions, such as heat, dryness, and decompression, and ultraviolet rays. Based on these rheological and biological effects, its unique properties with respect to biorefinery have been discussed here.


Assuntos
Clorófitas/química , Polissacarídeos/química , Emulsões , Matriz Extracelular de Substâncias Poliméricas/química , Aditivos Alimentares/química , Aditivos Alimentares/isolamento & purificação , Aditivos Alimentares/farmacologia , Microscopia de Força Atômica , Estrutura Molecular , Peso Molecular , Polissacarídeos/isolamento & purificação , Polissacarídeos/farmacologia , Espectroscopia de Infravermelho com Transformada de Fourier , Viscosidade
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