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1.
Carbohydr Polym ; 247: 116740, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32829859

RESUMO

Pulmonary fibrosis (PF) is a lung disease with highly heterogeneous and mortality rate, but its therapeutic options are now still limited. Corona virus disease 2019 (COVID-19) has been characterized by WHO as a pandemic, and the global number of confirmed COVID-19 cases has been more than 8.0 million. It is strongly supported for that PF should be one of the major complications in COVID-19 patients by the evidences of epidemiology, viral immunology and current clinical researches. The anti-PF properties of naturally occurring polysaccharides have attracted increasing attention in last two decades, but is still lack of a comprehensively understanding. In present review, the resources, structural features, anti-PF activities, and underlying mechanisms of these polysaccharides are summarized and analyzed, which was expected to provide a scientific evidence supporting the application of polysaccharides for preventing or treating PF in COVID-19 patients.


Assuntos
Betacoronavirus , Produtos Biológicos/uso terapêutico , Infecções por Coronavirus/complicações , Pandemias , Pneumonia Viral/complicações , Polissacarídeos/uso terapêutico , Fibrose Pulmonar/tratamento farmacológico , Animais , Antioxidantes/farmacologia , Antioxidantes/uso terapêutico , Bleomicina/toxicidade , Modelos Animais de Doenças , Avaliação Pré-Clínica de Medicamentos , Proteína Forkhead Box O3/fisiologia , Fungos/química , Ribonucleoproteína Nuclear Heterogênea D0/fisiologia , Humanos , Macrófagos/efeitos dos fármacos , Medicina Tradicional Chinesa , Camundongos , Neutrófilos/efeitos dos fármacos , Fitoterapia , Plantas Medicinais/química , Polissacarídeos/farmacologia , Fibrose Pulmonar/induzido quimicamente , Fibrose Pulmonar/etiologia , Fibrose Pulmonar/prevenção & controle , RNA Longo não Codificante/antagonistas & inibidores , Ratos , Alga Marinha/química , Transdução de Sinais/efeitos dos fármacos , Proteína Smad2/fisiologia , Proteína Smad3/fisiologia , Fator de Crescimento Transformador beta1/antagonistas & inibidores
2.
Mar Pollut Bull ; 159: 111504, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32758796

RESUMO

Mediterranean Sea is among the world's leading tourist destinations; however, the sharp increase in tourists during the high season may affect coastal seawater. The main aim of this study was to evaluate the occurrence and temporal variation of anthropogenic nutrients in coastal seawater in relation to tourist flows in three Mediterranean islands (Cyprus, Sicily and Rhodes), through short-term macroalgae deployments, coupled with δ15N analysis and GIS mapping. In all islands, an overall increase in macroalgae δ15N occurred over the deployment carried out in August in the tourist sites, suggesting the presence of anthropogenic nutrients. Decreasing δ15N values occurred at increasing distance from the coastline in two out of the three islands (Cyprus and Sicily). This study revealed the usefulness of the approach used in the assessment of tourism impact in terms of trophic enrichment and its potential to support competent authorities for the development of sustainable coastal management plans.


Assuntos
Monitoramento Ambiental , Alga Marinha , Chipre , Ilhas do Mediterrâneo , Mar Mediterrâneo , Nutrientes , Sicília
3.
Aquat Toxicol ; 225: 105552, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32615475

RESUMO

There is scarce investigation addressing interpopulation tolerance responses to address the influence of a history of chronic stress exposure, as that occurring in polluted environments, in photoautotrophs. We evaluated ecophysiological (photosynthetic activity) and metabolic (oxidative stress and damage) responses of two populations of green macroalga Ulva compressa from polluted (Ventanas) and non-polluted (Cachagua) localions of central Chile, and exposed to controlled hypersalinity conditions of 32 (control), 42, 62 and 82 psu (practical salinity units) for 6 h, 48 h and 6 d. Both primary production (ETRmax) and photosynthetic efficiency (αETR) were generally higher in the population from Cachagua compared to Ventanas at all times and salinities. Moreover, at most experimental times and salinities the population from Ventanas had greater levels of H2O2 and lipid peroxidation that individuals from Cachagua. Total ascorbate was higher in the population of Cachagua than Ventanas at 42 and 82 psu after 6 and 48 h, respectively, while at 6 d concentrations were similar between both populations at all salinities. Total glutathione was greater in both populations after 6 h at all salinities, but at 48 h its concentrations were higher only in the population from Cachagua, a trend that was maintained at 6 d under 82 psu only. Reduced and oxidized ascorbate (ASC and DHA, respectively) and glutathione (GSH and GSSG, respectively) demonstrated similar patterns between U. compressa populations, with an increase oxidation with greater salinities but efficient recycling to maintain sufficient batch of ASC and GSH. When assessing the expression of antioxidant enzymes catalase (CAT), superoxide dismutase (SOD) and dehydroascorbate reductase (DHAR), while the population of Ventanas displayed a general trend of upregulation with increasing salinities along the experiments, U. compressa from Cachagua revealed patterns of downregulation. Results demonstrated that although both populations were still viable after the applied hypersalinities during all experimental times, biological performance was usually more affected in the population from the Ventanas than Cachagua, likely due to a depressed baseline metabolism after a long history of exposition to environmental pollution.


Assuntos
Ulva/fisiologia , Poluentes Químicos da Água/toxicidade , Antioxidantes/metabolismo , Ácido Ascórbico/metabolismo , Catalase/metabolismo , Chile , Poluição Ambiental , Glutationa/metabolismo , Peróxido de Hidrogênio/metabolismo , Peroxidação de Lipídeos , Oxirredução , Estresse Oxidativo , Salinidade , Alga Marinha/metabolismo , Superóxido Dismutase/metabolismo , Ulva/enzimologia
4.
Environ Sci Process Impacts ; 22(8): 1678-1687, 2020 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-32638776

RESUMO

Microplastics are ubiquitous in the environment. Due to still rising global production, the emission of polymers into the environment and the abundance of microplastics have increased accordingly. Due to the long mineralization processes of microplastics, distribution in all compartments can be found. The hydrophobic surfaces of the particles can sorb chemical pollutants, therefore providing a potential pathway to accumulation by organisms within the food web. However, little is known about how long-term aging and degradation processes of microplastics can affect the sorption behaviours of organic pollutants on the particles. In this study, important industrial additives of emerging environmental concern, such as hydrophobic aromatic amines, were studied in relation to their sorption behaviour on high-density polyethylene and low-density polyethylene microplastics. Diphenylamine (log POW (logarithmic octanol-water partition coefficient) = 3.5) showed strong sorption, carbamazepine (log POW = 2.5) showed moderate sorption, and aniline (log POW = 0.9) showed no detectable sorption behaviour. Artificially aged particles exposed to photochemical aging and long-term mechanical treatment in water were compared to pristine microplastics. While mechanically aged microplastics promoted the sorption of aromatic amines, photochemically aged particles showed a decrease in sorption capacity due to changed surface chemistry. Importantly, the sorption capacity increased with increasing salinity, leading to strong implications for ocean systems, as an elevated uptake of pollutants could occur under marine conditions. Moreover, our study demonstrates that the ecotoxicological effects of diphenylamine on the growth of the seaweed Ulva (sea lettuce, Chlorophyta) were reduced in the presence of microplastics. As the plastic particles withdrew enough contaminants from solution, even toxic levels of diphenylamine (c = 10-4 M) became tolerable for the algae. However, the pollutants initially sorbed on the microplastics can be released again at a later point in the ageing process, thus having delayed pollution potential.


Assuntos
Plásticos , Polietileno , Alga Marinha , Poluentes Químicos da Água , Adsorção , Aminas , Microplásticos , Modelos Químicos
5.
Bioresour Technol ; 315: 123795, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32659424

RESUMO

Hydrogen production from Saccharina Japonica by simultaneous dark fermentation (DF) and microbial electrolysis cell (MEC), called sDFMEC, was studied. In the novel sDFMEC process, substrates were converted to H2 and volatile fatty acids (VFAs) by DF in the bulk phase, and VFAs are simultaneously oxidized by the exoelectrogens in the microbial film on anode electrode with further production of H2 at the cathode. The sDFMEC process was compared with DF and a combined process of DF and MEC in series (DF-MEC) in terms of H2 production. The overall H2 production from S. Japonica in sDFMEC process was higher (438.7 ± 13.3 mL/g-TS), than DF (54.6 ± 0.8 mL/g-TS) and DF-MEC (403.5 ± 7.9 mL/g-TS) process, respectively, which is approximately 3-times higher than those reported in the literature.


Assuntos
Fontes de Energia Bioelétrica , Alga Marinha , Eletrólise , Ácidos Graxos Voláteis , Fermentação , Hidrogênio
6.
Mar Environ Res ; 159: 104966, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32662427

RESUMO

The seaweed Caulerpa cylindracea (Sonder) is one of the most successful marine bioinvaders worldwide. Caulerpa cylindracea can influence the quantity and biochemical composition of sedimentary organic matter (OM). However, it is still unknown if the effects of C. cylindracea on both OM and small metazoans (i.e. meiofauna) can change according to different sediment deposition rates. To provide insights on this, we investigated the biochemical composition of sediments along with the abundance and composition of meiofaunal assemblages in sediments colonized and not-colonized by the seaweed C. cylindracea under different regimes of sediment deposition. Our results show that the presence of the invasive alga C. cylindracea could alter quantity, biochemical composition, and nutritional quality of organic detritus and influence the overall functioning of the benthic system, but also that the observed effects could be context-dependent. In particular, we show that the presence of C. cylindracea could have a positive effect on meiofaunal abundance wherever the sediment deposition rates are low, whereas the contextual presence of high to medium sedimentation rates can provoke an accumulation of sedimentary organic matter, less favourable bioavailability of food for the benthos, and consequent negative effects on meiofauna.


Assuntos
Caulerpa , Alga Marinha , Ecossistema , Sedimentos Geológicos
7.
Proc Biol Sci ; 287(1928): 20200709, 2020 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-32517616

RESUMO

Marine heatwaves (MHWs) have been documented around the world, causing widespread mortality of numerous benthic species on shallow reefs (less than 15 m depth). Deeper habitats are hypothesized to be a potential refuge from environmental extremes, though we have little understanding of the response of deeper benthic communities to MHWs. Here, we show how increasing depth moderates the response of seaweed- and coral-dominated benthic communities to an extreme MHW across a subtropical-temperate biogeographical transition zone. Benthic community composition and key habitat-building species were characterized across three depths (15, 25 and 40 m) before and several times after the 2011 Western Australian MHW to assess resistance during and recovery after the heatwave. We found high natural variability in benthic community composition along the biogeographic transition zone and across depths with a clear shift in the composition after the MHW in shallow (15 m) sites but a lot less in deeper communities (40 m). Most importantly, key habitat-building seaweeds such as Ecklonia radiata and Syctothalia dorycarpa which had catastrophic losses on shallow reefs, remained and were less affected in deeper communities. Evidently, deep reefs have the potential to act as a refuge during MHWs for the foundation species of shallow reefs in this region.


Assuntos
Organismos Aquáticos/fisiologia , Biodiversidade , Recifes de Corais , Calor Extremo , Animais , Alga Marinha
8.
Aquat Toxicol ; 224: 105513, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32504860

RESUMO

Ulva prolifera is a macroalgae that forms massive blooms, negatively impacting natural communities, aquaculture operations and recreation. The effects of the natural products, eugenol, ß-myrcene, citral and nonanoic acid on the growth rate, antioxidative defense system and photosynthesis of Ulva prolifera were investigated as a possible control strategy for this harmful taxon. Negative effects on growth were observed with all four chemicals, due to the excessive production of reactive oxygen species and oxidative damage to the thalli. However, the response of U. prolifera under the four chemicals stress was different at the cellular level. ß-myrcene, the most effective compound in terms of growth inhibition, induced oxidative stress as shown by the damage of total antioxidant capacity (T-AOC) and the downregulation of the glutathione-ascorbate (GSH-ASA) cycle which inhibited the antioxidative system. This chemical also inhibited photosynthesis and photoprotection mechanisms in U. prolifera, resulting in growth limitation. In contrast, U. prolifera was less affected by the second tested chemical, eugenol, and showed no significant change on photosynthetic efficiency in the presence of the chemical. The inhibition effects of the third and fourth tested chemicals, nonanoic acid and citralon, on growth and on the antioxidant defense system in U. prolifera were inferior. These results provide a potential avenue for controlling green tides in the future.


Assuntos
Antioxidantes/metabolismo , Feromônios/toxicidade , Fotossíntese/efeitos dos fármacos , Alga Marinha/efeitos dos fármacos , Ulva/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Fotossíntese/fisiologia , Alga Marinha/metabolismo , Alga Marinha/fisiologia , Ulva/crescimento & desenvolvimento , Ulva/metabolismo
9.
Proc Biol Sci ; 287(1929): 20200732, 2020 06 24.
Artigo em Inglês | MEDLINE | ID: mdl-32546101

RESUMO

Planning for future ocean conditions requires historical data to establish more informed ecological baselines. To date, this process has been largely limited to instrument records and observations that begin around 1950. Here, we show how marine macroalgae specimens from herbaria repositories may document long-term ecosystem processes and extend historical information records into the nineteenth century. We tested the effect of drying and pressing six macroalgae species on amino acid, heavy metal and bulk stable isotope values over 1 year using modern and archived paper. We found historical paper composition did not consistently affect values. Certain species, however, had higher variability in particular metrics while others were more consistent. Multiple herbaria provided Gelidium (Rhodophyta) samples collected in southern Monterey Bay from 1878 to 2018. We examined environmental relationships and found δ15N correlated with the Bakun upwelling index, the productivity regime of this ecosystem, from 1946 to 2018. Then, we hindcasted the Bakun index using its derived relationship with Gelidium δ15N from 1878 to 1945. This hindcast provided new information, observing an upwelling decrease mid-century leading up to the well-known sardine fishery crash. Our case study suggests marine macroalgae from herbaria are an underused resource of the marine environment that precedes modern scientific data streams.


Assuntos
Ecossistema , Alga Marinha , California , Movimentos da Água
10.
Environ Sci Pollut Res Int ; 27(26): 32481-32493, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32506400

RESUMO

The present study evaluated the sequential biodiesel-bioethanol production from seaweeds. A total of 22 macroalgal species were collected at different seasons and screened based on lipid and carbohydrate contents as well as biomass production. The promising species was selected, based on the relative increase in energy compounds (REEC, %), for further energy conversion. Seasonal and annual biomass yields of the studied species showed significant variations. The rhodophyte Amphiroa compressa and the chlorophyte Ulva intestinalis showed the highest annual biomass yield of 75.2 and 61.5 g m-2 year-1, respectively. However, the highest annual carbohydrate productivity (ACP) and annual lipid productivity (ALP) were recorded for Ulva fasciata and Ulva intestinalis (17.0 and 3.0 g m-2 year-1, respectively). The later was selected for further studies because it showed 14.8% higher REEC value than Ulva fasciata. Saturated fatty acids (SAFs) showed 73.4%, with palmitic acid as a dominant fatty acid (43.8%). Therefore, biodiesel showed high saturation degree, with average degree of unsaturation (ADU) of 0.508. All the measured biodiesel characteristics complied the international standards. The first route of biodiesel production (R1) from Ulva intestinalis showed biodiesel recovery of 32.3 mg g-1 dw. The hydrolysate obtained after saccharification of the whole biomass (R2) and lipid-free biomass (R3) contained 1.22 and 1.15 g L-1, respectively, reducing sugars. However, bioethanol yield from R3 was 0.081 g g-1 dw, which represented 14.1% higher than that of R2. Therefore, application of sequential biofuel production using R3 resulted in gross energy output of 3.44 GJ ton-1 dw, which was 170.9% and 82.0% higher than R1 and R2, respectively. The present study recommended the naturally-grown Ulva intestinalis as a potential feedstock for enhanced energy recovery through sequential biodiesel-bioethanol production.


Assuntos
Alga Marinha , Ulva , Biocombustíveis , Biomassa , Ácidos Graxos
11.
J Environ Manage ; 268: 110666, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32510431

RESUMO

The worlds' coral reefs are declining due to the combined effects of natural disturbances and anthropogenic pressures including thermal coral bleaching associated with global climate change. Nearshore corals are receiving increased anthropogenic stress from coastal development and nutrient run-off. Considering forecast increases in global temperatures, greater understanding of drivers of recovery on nearshore coral reefs following widespread bleaching events is required to inform management of local stressors. The west Pilbara coral reefs, with cross-shelf turbidity gradients coupled with a large nearby dredging program and recent history of repeated coral bleaching due to heat stress, represent an opportune location to study recovery from multiple disturbances. Mean coral cover at west Pilbara reefs was monitored from 2009 to 2018 and declined from 45% in 2009 to 5% in 2014 following three heat waves. Recruitment and juvenile abundance of corals were monitored from 2014 to 2018 and were combined with biological and physical data to identify which variables enhanced or hindered early-stage coral recovery of all hard corals and separately for the acroporids, the genera principally responsible for recovery in the short-term (<7 years). From 2014 to 2018, coral cover increased from 5 to 10% but recovery varied widely among sites (0-13%). Hard coral cover typically recovered most at shallower sites that had higher abundance of herbivorous fish, less macroalgae, and lower turbidity. Similarly, acroporid corals recovered most at sites with lower turbidity and macroalgal cover. Juvenile acroporid densities were a good indicator of recovery at least two years after they were recorded. However, recruitment to settlement tiles was not a good predictor of total coral or acroporid recovery. This study shows that coral recovery can be slower in areas of high turbidity and the rate may be reduced by local pressures, such as dredging. Management should focus on improving or maintaining local water quality to increase the likelihood of coral recovery under climate stress. Further, in turbid environments, juvenile coral density predicts early coral recovery better than recruits on tiles and may be a more cost-effective technique for monitoring recovery potential.


Assuntos
Antozoários , Alga Marinha , Animais , Mudança Climática , Recifes de Corais , Peixes
12.
Mar Pollut Bull ; 155: 110962, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32469791

RESUMO

The aim of the study was to assess the effect of seaweed cultivation on the coastal environment. We analysed a multitude of environmental parameters using an asymmetrical before after control impact (BACI) design, comparing the seaweed farm (impact) with multiple unaffected locations (controls). The seaweed farm had a significant positive effect on benthic infauna (p<0.05) and was found to attract 17 mobile faunal and 7 other seaweed species, indicating that the farmed crop may provide habitat to mobile faunal species. A light attenuation of approximately 40% at 5m depth was noted at the peak of the seaweed biomass just before harvest. No changes were observed in benthic oxygen flux, dissolved nutrient concentrations, and benthic mobile fauna between farm and control sites. These results show that seaweed aquaculture has limited environmental effects, especially compared to other forms of aquaculture such as fish and bivalve farming.


Assuntos
Kelp , Feófitas , Alga Marinha , Animais , Aquicultura , Meio Ambiente
13.
Bioresour Technol ; 312: 123539, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32447122

RESUMO

This study investigates the integration of hydrothermal carbonisation (HTC) with anaerobic digestion (AD) as a valorisation route for two macroalgae species; S. latissima (SL) and F. serratus (FS). HTC reactions were conducted at temperatures of 150 °C, 200 °C and 250 °C, with resulting hydrochars, process waters and hydrothermal slurries assessed for biomethane potential yields. Un-treated SL generated similar biomethane levels compared to all SL slurries. Whereas all FS slurries improved biomethane yields compared to un-treated FS. Hydrochars represent a greater energy carrier if used as a solid fuel, rather than a feedstock for anaerobic digestion. Integrating HTC and AD, through hydrochar combustion and process water digestion has a greater energetic output than anaerobic digestion of the un-treated macroalgae. Treatment at 150 °C, with separate utilisation of products, can improve the energetic output of S. latissima and F. serratus by 47% and 172% respectively, compared to digestion of the un-treated macroalgae.


Assuntos
Alga Marinha , Anaerobiose , Carbono , Temperatura
14.
Proc Biol Sci ; 287(1927): 20200366, 2020 05 27.
Artigo em Inglês | MEDLINE | ID: mdl-32453990

RESUMO

A number of tropical reefs have transitioned from coral to macroalgal dominance, but the role of macroalgal competition in coral decline is debated. There is a need to understand the relative roles of direct coral-algal effects versus indirect, microbially mediated effects shaping these interactions, as well as the relevant scales at which interactions operate under natural field, as opposed to laboratory, conditions. We conducted a manipulative field experiment investigating how direct contact versus close proximity (approx. 1.5 cm) with macroalgae (Galaxaura rugosa, Sargassum polycystum) impacted the growth, photosynthetic efficiency, and prokaryotic microbiome of the common Indo-Pacific coral Acropora millepora. Both coral growth and photosynthetic efficiency were suppressed when in direct contact with algae or their inert mimics--but not when in close proximity to corals without direct contact. Coral microbiomes were largely unaltered in composition, variability, or diversity regardless of treatment, although a few uncommon taxa differed in abundance among treatments. Negative impacts of macroalgae were contact dependent, accounted for by physical structure alone and had minimal effects on coral microbiomes. The spatial constraints of these interactions have important implications for understanding and predicting benthic community dynamics as reefs degrade.


Assuntos
Antozoários/fisiologia , Alga Marinha/fisiologia , Animais , Comportamento Competitivo , Ecossistema , Dinâmica Populacional
15.
Food Chem ; 327: 127078, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32454272

RESUMO

The potential of cross-processing herring or salmon by-products with brown seaweed, shrimp peeling by-products and lingonberry press cake (called "helpers") to minimize lipid oxidation during acid/alkaline pH-shift protein isolation was evaluated. Lingonberry press cake remarkably reduced levels of lipid hydroperoxides, malondialdehyde (MDA) and 4-hydroxy-trans2-hexenal (HHE) in both herring and salmon protein isolates (PI) while seaweed and shrimp by-product mitigated generation of MDA and HHE in herring PI. The salmon PI, however, by itself had very low oxidation levels. Cross-processing reduced protein yield compared with the classical pH-shift process by diminishing protein solubility, but still, the alkaline process version was promising. The color of the PIs varied greatly between different process combinations, reflecting partitioning of natural pigments into isolates. Altogether, cross-processing seems a promising tool for inhibition of lipid oxidation during pH-shift processing of sensitive fish by-products, with the alkaline version and lingonberry press cake being closest at hand for further studies.


Assuntos
Produtos Pesqueiros/análise , Peixes , Lipídeos/química , Alimentos Marinhos , Alga Marinha/química , Vaccinium vitis-Idaea/química , Animais , Concentração de Íons de Hidrogênio , Oxirredução , Solubilidade
16.
Environ Sci Pollut Res Int ; 27(21): 26406-26418, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32363459

RESUMO

Phytoremediation is an innovative, eco-friendly, and solar-driven technique, which becomes a well-known alternative solution for remediation of hazardous dyes from wastewater. In present research work, potential of a submerged fresh water macroalgae Chara vulgaris L. (C. vulgaris) examined for removal of acidic azo dye methyl red (MR) in its solution form. A series of experiments were done with C. vulgaris to predict the effects of different parameters viz. contact time, initial dye concentration, amount of macroalgae, and pH. The increase in initial dye concentration directly impacts on the potential of macroalgae. The decolorization percentage declined with increase in initial dye concentration. The equilibrium condition was found to achieve after contact time of approximately 48 h. The decolorization of MR dye was found to be favorable at pH 5. The macroalgae was successfully utilized repeatedly with MR for eight cycles in batch experiments. The kinetics of phytoremediation of MR dye was studied with help of pseudo-first-order, pseudo-second-order, and Elovich kinetic models and the results were well suited to pseudo-second-order kinetic model with the correlation value R2 ≥ 0.99. In addition, the experimental data was also assessed by using Langmuir and Freundlich adsorption equilibrium isotherms. The results of phytoremediation data was found to be in favor of Freundlich equilibrium isotherm which having the correlation value R2 ≥ 0.977. The intraparticle diffusion model also studied to interpret the macroalgae phytoremediation mechanism for phytoremediation of MR. The surface interactions of C. vulgaris were investigated before and after the removal of dye with Fourier transform-infrared spectroscopy (FTIR) technique. On the basis of these studies, a hypothetical mechanism has also been proposed to depict the phytoremediation of acidic azo dye by C. vulgaris.


Assuntos
Chara , Alga Marinha , Poluentes Químicos da Água/análise , Adsorção , Compostos Azo , Biodegradação Ambiental , Corantes , Concentração de Íons de Hidrogênio , Cinética , Termodinâmica
17.
Bioresour Technol ; 311: 123548, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32454421

RESUMO

A novel seaweed-hydrolyzing strain designated as Pseudoalteromonas sp. Alg6B was isolated from the surface of brown seaweed (Laminaria japonica). The activity of crude alginate lyase produced by Alg6B was 54.5 U/ml and the main products of hydrolyzing alginate were disaccharide and tetrasaccharide. The hydrolysis rate of seaweed reached up to 97% after combining 3% (v/v) Alg6B and 0.2% (w/v) solid cellulase. In kelp hydrolysate, the contents of nutrients are much more than raw seaweed. Alg6B grows quickly and has the ability of producing alginate oligosaccharides with low molecular weight (MW) (≤2 kDa). Furthermore, this study demonstrates that a combination of microbial alginate lyase and cellulase could almost hydrolyze seaweed completely. This research indicated that Alg6B could provide a feasible pathway to produce alginate oligosaccharides (AOS), and the synergistic effect of alginate lyase and cellulase on seaweed bioconversion can potentially pave the way to the sustainable production of seaweed fertilizer.


Assuntos
Celulase , Laminaria , Alga Marinha , Alginatos , Polissacarídeo-Liase
18.
Sci Total Environ ; 724: 138133, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32268287

RESUMO

Mercury (Hg) removal by six different living marine macroalgae, namely, Ulva intestinalis, Ulva lactuca, Fucus spiralis, Fucus vesiculosus, Gracilaria sp., and Osmundea pinnatifida was investigated in mono and multi-contamination scenarios. All macroalgae were tested under the same experimental conditions, evaluating the competition effects with all elements at the same initial molar concentration of 1 µmol dm-3. The presence of the main potentially toxic elements (Cd, Cr, Cu, Ni, and Pb) and rare earth elements (La, Ce, Pr, Nd, Eu, Gd, Tb, and Y) has not affected the removal of Hg. Characterizations of the macroalgae by FTIR before and after the biosorption/bioaccumulation assays suggest that Hg was mainly linked to sulfur-functional groups, while the removal of other elements was related with other functional groups. The mechanisms involved point to biosorption of Hg on the macroalgae surface followed by possible incorporation of this metal into the macroalgae by metabolically active processes. Globally, the green macroalgae (Ulva intestinalis, Ulva lactuca) showed the best performances for Hg, potential toxic elements and rare earth elements removal from synthetic seawater spiked with 1 µmol dm-3 of each element, at room temperature and pH 8.5.


Assuntos
Mercúrio , Metais Terras Raras , Alga Marinha , Poluentes Químicos da Água/análise , Poluição da Água
19.
Environ Sci Pollut Res Int ; 27(17): 22120-22126, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32304044

RESUMO

This study was performed to explore acute toxicity of biologically synthesized gold nanoparticles (AuNPs) to a model organism Daphnia magna. Hence, using aqueous extract of marine macroalga Saccharina japonica, two AuNPs including SJ-AuNPs-72 (72.6 ± 43.8 nm) and SJ-AuNPs-10 (10.8 ± 2.8 nm) were synthesized. These AuNPs were characterized by different techniques such as UV-Vis spectrophotometry, transmission electron microscopy (TEM), dynamic light scattering (DLS), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and energy-dispersive X-ray spectroscopy (EDX). The 48-h LC50 values of SJ-AuNPs-72 and SJ-AuNPs-10 to D. magna were 1.57 ± 0.07 and 2.69 ± 0.12 mg/L, respectively, showing greater toxicity of SJ-AuNPs-72. After exposure of daphnids to treatments, AuNPs were accumulated in gut tract, and lipid droplets under the Daphnia carapace were also observed. Whereas studies on toxicity of biosynthesized AuNPs are still scarce, the achievements of this work are helpful for understanding the toxicity of biosynthesized AuNPs to crustacean D. magna.


Assuntos
Nanopartículas Metálicas , Alga Marinha , Animais , Daphnia , Difusão Dinâmica da Luz , Ouro , Extratos Vegetais , Espectroscopia de Infravermelho com Transformada de Fourier
20.
Environ Sci Pollut Res Int ; 27(19): 24272-24283, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32306249

RESUMO

The invasive marine macroalga Chaetomorpha valida blooms frequently in Apostichopus japonicus culture ponds in North China, resulting in negative environmental consequences. The factors driving this algal overgrowth are unclear. Previous studies observed that eutrophication strongly influences abnormal growth of nuisance macrophytes, but relatively few studies have addressed the types and abundance of nitrogen in A. japonicus culture ponds during the seasonal progression of a C. valida bloom and the effects of nitrogen source and N/P on C. valida growth and photosynthesis. In this study, we describe the structural features of nitrogen abundance and the seasonal progression of a C. valida bloom and uncover a relationship between nitrogen enrichment and C. valida growth. Common garden experiments demonstrated that C. valida can utilize different forms of nitrogen in the environment for rapid growth. Growth rate and photosynthesis capacity were related to the nitrogen source and N/P ratio. This study will provide a reference for maintenance of ecological balance and healthy aquaculture in A. japonicus culture ponds.


Assuntos
Nitrogênio/análise , Alga Marinha , China , Eutrofização , Fotossíntese
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