Alga Scenedesmus Quadricauda Research Articles

Allelopathic effects of three lichen secondary metabolites on cultures of aposymbiotically grown lichen photobionts and free-living alga Scenedesmus quadricauda

In the present work, we studied the influence of lichen secondary metabolites (evernic acid, orcinol, usnic acid) on selected species of algae: Trebouxia erici, photobiont of lichen Cladonia cristatella producing typical lichen secondary metabolites, Coccomyxa solorinae-saccatae, photobiont of lichen Solorina saccata which does not produce typical secondary metabolites of lichens, and free-living alga Scenedesmus quadricauda.For the determination of the cytotoxic effects of these compounds, algae were cultivated on the surface of disks composed of glass microfibers, in quantities of 0.1 mg/disk for each metabolite. After 14-days prolonged cultivation, we analysed selected physiological parameters: growth of algae, chlorophyll a fluorescence, the content of ascorbic acid, content of reduced and oxidized glutathione and contents of selected organic acids. The presence of secondary compounds typically inhibited the growth of tested algae and chlorophyll a fluorescence. In the presence of evernic acid and usnic acid, we observed a decrease of ascorbic acid, glutathione, and significant changes in the composition of organic acids.Lichen metabolites, except for their other biological and ecological roles, may act as phytotoxic substances, causing oxidative stress in photobiont cells. These metabolites may play an important role in the “controlled parasitism” of fungal partner on algal/cyanobacterial partner of symbiosis. Differences in the sensitivity of algal cells from different habitats to lichen compounds are, however, not understood sufficiently.

The use of an algal bioindicator in the assessment of different chemical remediation strategies for PAH-contaminated soils and sediments

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous petroleum-derived pollutants that tend to accumulate in soils and sediments. Among the in situ chemical oxidation technologies applied at PAH-contaminated sites are Fenton reagent (FN), persulfate ion (PS) and permanganate ion (PM). The natural phytoplankton of an aquatic environment is useful as a biological indicator of the treatment efficacy of pollutant degradation. The objective of this work was to assess the use of an algal species, native from Los Barreales Reservoir (Argentina), as an efficacy indicator of the chemical remediation of PAH-contaminated soils and sediments. Oxidations with FN, PS or PM were carried out on soils and sediments previously contaminated with two types of PAHs (phenanthrene (Ph) or Benzo(a)anthracene (Ba)), analysing pH, residual oxidant, PAH degradation and heterotrophic bacteria abundance in soils or sediments after 7 days. Then, a bioassay was carried out by incubating the obtained soils or sediments, and the native alga Scenedesmus quadricauda (Turpin, Brébisson), analysing its abundance after 7 days. S. quadricauda abundance was related to PAH degradation efficacy, residual oxidants and changes in system pH. In this sense, the application of PS produced the lowest growth of the indicator in assays both with soils and sediments. Fenton reaction results varied depending on the contaminating PAH, with the best percentages of PAH degradation and growth of S. quadricauda for Ba. PM oxidation resulted in the best development of the indicator. This study constitutes a first approach to the use of S. quadricauda as an efficiency indicator of soil/sediment chemical remediation.

Toxicological Effects of Mercuric Chloride Exposure on Scenedesmus quadricauda

Mercuric chloride (HgCl2) is a common heavy-metal pollutant widely used in commercial products and industry, but its excessive use and uncontrolled discharge have caused great harm to aquatic environments and human health. To research the mechanisms of HgCl2 toxicity in aquatic organisms, this study cultured the green alga Scenedesmus quadricauda in a gradient of HgCl2 concentrations (0, 0.1, 0.3, 0.5, 0.7, and 0.9 mg/L) for 9 days. The results showed that: (1) when the concentrations of HgCl2 were high (≥0.7 mg/L), the toxic effects completely inhibited the growth of algal cells, the culture liquid changed from green to light yellow, and cells aggregated and sank to the bottom. Submicroscopic structural imaging showed that at 0.9 mg/L HgCl2, the algal cells were seriously damaged and obvious plasma–wall separation occurred. Furthermore, the arrangement of photosynthetic lamellae became disordered and the nuclei and protein nuclei faded or even disappeared. (2) When the concentrations of HgCl2 were low and medium (≤0.5 mg/L), the activity of superoxide dismutase (SOD) in algal cells increased in the first five days, but the degree of increase was smaller than in the control group. However, under high HgCl2 concentrations (≥0.7 mg/L), the activity of SOD began to decrease sharply on the seventh day. The activity of peroxidase (POD) decreased more obviously than that of SOD. (3) Under medium and high HgCl2 concentrations (≥0.5 mg/L), the content of malondialdehyde (MDA) in algal cells increased over time, and had not decreased again by the last day of measurement. In contrast, the contents of total protein (TP) and soluble sugar (SS) both exhibited decreasing trends under high HgCl2 concentrations. (4) When the HgCl2 concentrations were ≥0.7 mg/L, the content of photosynthetic pigments in algal cells decreased, and the light quantum yield of PS Ⅱ decreased. At the same time, as culture time progressed, the photosynthetic electron transfer and energy-conversion efficiency were seriously damaged and photosynthesis never returned to normal levels. This research provides a reference for understanding the mechanism by which HgCl2 pollution affects aquatic ecosystems and may help with pollution management in the future.

Assessment of the Efficiency and Safety of the Process for Utilization of Formaldehyde-Containing Solid Waste by the Method of Medium Temperature Dry Pyrolysis

An assessment of the efficiency and safety of the formaldehyde decontamination process containing solid waste of wood-chip boards by method of medium-temperature dry pyrolysis at the installation developed by the authors was evaluated. Sawdust of chip boards and coke ash residue after their pyrolysis were subjected to biological examination. The test objects were Daphnia magna Straus, algae Scenedesmus quadricauda and luminescent bacteria. It was revealed that pyrolysis of these wastes at the proposed plant will reduce the load on the hydrosphere and reduce the ratio of dilution of water extracts by more than half. Analysis of the composition of pyrolysis gases showed that the mass concentration of nitrogen oxides and carbon in the air of the working zone does not exceed the MPC of the working zone and MPC of settlements. The conclusion on environmental safety of the process of pyrolysis of formaldehyde-containing solid wastes at the proposed installation is made.

Divergent responses of diverse microalgae commonly found in drinking water source water to UV-C treatment

Microalgae pose major problems for drinking water treatment processes either through membrane fouling or through blooming events in source water during the summer months. Disinfection treatments such as chlorination and UV-C treatment of drinking water are designed to remove microorganisms including microalgae and bacteria. In order to treat water efficiently it is critical to understand the effect of UV-C treatment on the viability and vitality of phytoplankton. Moreover, this information can be used to assess the utility of UV-C treatment as a potential pre-treatment option for water clean-up. In this study we tested the population growth of 6 phytoplankton species representing three major taxonomic groups (green algae, diatoms and cyanobacteria), commonly found in freshwater lakes in North America and relevant for water treatment facilities. We exposed these species to UV-C treatment and monitored their post-exposure population growth over a 52–55-day period using a plate-based MPN (most probable number) method. We found the green alga Scenedesmus quadricauda and the cyanobacterium Anabaena flos-aquae to be most tolerant to the treatment, while the cyanobacterium Microcystis aeruginosa and the diatom Asterionella formosa were found to be most sensitive with viability being reduced at comparatively lower doses. No significant delays in growth post treatment (i.e. time lags) were reported within species. Asterionella formosa and Aulacoseira granulata showed the longest time lags of all species, which might be in part correlated with DNA repair mechanisms and other physiological adaptations. This work provides the basis for the assessment of UV-C treatment efficacy on freshwater phytoplankton.

Technology of Obtaining Sorbents Based on Metal Dust and Carbonized Biopolymers for Purification of Surface and Waste Water From Oil and Oil Products

The results on the production of composite magnetosorbents (CMS) based on agricultural wastes (uncontaminated steel gas treatment dust – PGSN, sunflower husk, paraffin) for the treatment of contaminated water from oil and its products and minimizing the environmental impact of petrochemical enterprises are presented. Biotesting at two test sites (crustaceans Daphnia magna and algae Scenedesmus quadricauda) allowed us to establish that PSGN is non-toxic and can be used as a component of magnetosorbents. The resulting materials showed good physicochemical properties. It was shown that CMC have high hydrophobicity – the contact angle of contact was 125–137 degrees; buoyancy of the material for 96 hours did not decrease below 97–99 %; CMC had a low water absorption of 0.132–0.114 g/g. The oil intensity of the sorbents was 6.0 ± 0.15 g/g. Sorption equilibrium was achieved during the first 10–20 minutes contact of the material with oil and oil productsand remained constant. It has been established that the sorption process is influenced by the nature and thickness of the oil product layer. The maximum sorption capacity is achieved with a film thickness of 3.5 ± 0.15 mm.

A Study of acute toxicity to pyrethroid insecticide “KARATE” on fresh water alga Scenedesmus quadricauda (Turb.) Bereb.

A Study of acute toxicity to pyrethroid insecticide “KARATE” on fresh water alga Scenedesmus quadricauda (Turb.) Bereb.

Root exudated algicide of Eichhornia crassipes enhances allelopathic effects of cyanobacteria Microcystis aeruginosa on green algae

Eichhornia crassipes is an invasive, floating macrophyte and may have biocontrol functions on harmful cyanobacteria blooms. Eichhornia produces N-phenyl-2-naphthylamine (PNA), a compound which can inhibit algae. However, the impact of PNA on allelopathic effects of the cyanobacterium Microcystis aeruginosa on other phytoplankton species is not clear. In this study, we tested whether PNA can influence the allelopathic effect of M. aeruginosa on the green alga Scenedesmus quadricauda. S. quadricauda was more sensitive to PNA than M. aeruginosa, with 72 h-EC50 values of 0.42 and 3.66 mg L−1, respectively. In addition, PNA significantly enhanced allelopathy by M. aeruginosa on S. quadricauda. Consequently, PNA had a greater impact on the green algae when Microcystis was present. In complex ecosystems with multiple species that release allelopathic substances, unintended interspecific interactions may occur, where allelopathy plays an important role under artificial or even natural contexts. It is hard to predict the competition outcomes among allelopathic organisms in these complex ecosystems, therefore a precautionary approach is required for biological control of algae.

The Effects of Interspecific Interactions Between Bloom Forming Cyanobacteria and Scenedesmus quadricauda (Chlorophyta) on Their Photophysiology

Eutrophication and enhanced external nutrient loading of lakes and seas are most clearly reflected by increased cyanobacterial blooms, which are often toxic. Freshwater cyanobacteria produce a number of bioactive secondary metabolites, some of which have allelopathic properties, significantly influencing the biological processes of other algae, thereby affecting species composition and succession of the phytoplankton. The goal of this work was to investigate the influence of bloom-forming cyanobacterial exudates on the photophysiology of the green alga Scenedesmus quadricauda by chlorophyll fluorescence analysis. We were able to prove the effect of algal cell-free fltrates on the performance of S. quadricauda and demonstrate for the first time that the freshwater picocyanobacterium Cyanobium gracile has strong negative impact on the coexisting green alga. Neither the cyanotoxin (MYC, CYN and ATX) producing, nor the non-toxic strains showed any systematic effect on the production of S. quadricauda. Various strains of the cyanobacterium Cylindrospermopsis raciborskii inhibited the performance of the green alga independently of their origin. Our results urge further studies for a better understanding of the factors affecting the release of allelopathic compounds and the mechanisms of their effects on target organisms.

Calcium availability but not its content modulates metal toxicity in Scenedesmus quadricauda

Impact of calcium nutrition (pre-culture on solid medium with standard or elevated Ca dose, i. e. 0.17 and 4.40mM marked as low and high Ca) on acute metal toxicity (Cd, Mn and Pb, 24h of exposure to 10µM) in freshwater green alga Scenedesmus quadricauda was studied. Surprisingly, Ca content differed only slightly between low and high Ca samples and applied metals rather suppressed its amount. Na content was higher in metal-exposed high Ca samples, indicating that Ca/Na ratio may affect accumulation of metals. Content of heavy metals increased in order Cd < Mn < Pb and high Ca samples contained less metal than low Ca samples at least in absorbed fraction. Accumulation of ascorbic acid and thiols (GSH – glutathione and PC2 – phytochelatin 2) was affected mainly by Cd, GSH also by Mn and PC2 by Pb with often significant differences between low Ca and high Ca samples. Calcium nutrition also affected responses of algae to metals at the level of antioxidative enzyme activities (SOD, APX, and CAT) and elevated values were typically found in high Ca samples while ROS (hydrogen peroxide and superoxide radical) were mainly depleted in Mn treatment. These data confirm that Ca nutrition affects accumulation of metals in algae and metabolic parameters as observed in vascular plants but, unlike them, rather Ca/Na ratio than absolute Ca content seems to regulate the uptake of metals.

Ascorbic acid affects short-term response of Scenedesmus quadricauda to cadmium excess

Impact of ascorbate biosynthetic inhibitor (lycorine, LYC) on short-term cadmium (Cd) action (1h, 100μM) was studied in the green alga Scenedesmus quadricauda with 1h or 24h of LYC co-application. LYC suppressed Cd-induced increase in ascorbic acid and enhanced oxidative symptoms (ROS fluorescence) by modulating activities of antioxidative enzymes after 24h of addition (decrease in superoxide dismutase, catalase and ascorbate peroxidase activities). Prolonged (24h) exposure to LYC also affected content of Cd and quantitative changes of thiols (glutathione and phytochelatin 2) while Cd itself revealed interesting responses in algae maintained in the buffer for various time: these data indicate that in the studies involving axenic algal cultures, transfer of cells from sterile to non-sterile conditions modulates metal uptake. Among aliphatic organic acids, α-ketoglutaric, lactic and malic acids were variously influenced by Cd or lycorine, suggesting shift in the respiration and fermentation. It is concluded that ascorbic acid is involved in the protection of cells against Cd-induced ROS over-accumulation and metabolic changes were more expressive in the samples with 24h co-application of LYC though side impacts of LYC cannot be excluded. DESI-Orbitrap MS for the identification and visualization of lycorine was also successfully tested here for the first time.

Norfloxacin disrupts Daphnia magna-induced colony formation in Scenedesmus quadricauda and facilitates grazing

Environmental pollutants can negatively affect grazer-induced defenses in phytoplankton species and lead to the disruption of phytoplankton-zooplankton relationships. However, it is still not known whether norfloxacin (NOR), a widely used antibiotic, has such effects on plankton systems when released into the environment. Here, we investigated the colony-forming ability of the green alga Scenedesmus quadricauda as well as the behavior (hopping frequency and duration of quiescence) and grazing rate of the cladoceran Daphnia magna, when exposed to different NOR concentrations (0, 50, 500, 5000 and 50,00ugL−1), to determine the effects of NOR on the S. quadricauda-D. magna relationship. Colony size was generally unaffected by NOR but significantly increased when subjected to the stress of adding grazers; however, the combined effects of adding grazers and increasing NOR concentrations led to consistently decreased colony size compared to only adding grazers. The hopping frequency and the time spent on swimming of D. magna individuals decreased while their grazing rate increased with increasing NOR concentrations. Thus, NOR seemed to inhibit grazer-induced colony formation in S. quadricauda, resulting in more algal cells being consumed by grazers, despite inhibiting grazers’ feeding behavior. Considering that phytoplankton-zooplankton interaction plays an important role in determining ecological process of aquatic ecosystems, ecosystem function might be more affected by NOR contamination than previously recognized.

Process Analysis of Alkaline Flocculation Harvesting for Chaetoceros muelleri and Scenedesmus quadricauda

Alkaline flocculation could be an attractive microalgae harvesting method, because it is low-cost, low energy consumption, and non-toxic to microalgal cells, and the high pH effectively sterilizes the microalgal biomass as well as the process water. In this paper, the mechanism of alkaline flocculation process and the difference between the two strains marine diatom Chaetoceros muelleri #862 and freshwater algae Scenedesmus quadricauda #507 were analyzed. The particle size of C. muelleri #862 cells increased linearly with the increasing pH value which increased dramatically by nearly fivefolds after alkaline flocculation. When pH was below 10.5, the absolute value of zeta potential on the surface of C. muelleri #862 increased rapidly, and also the conductivity of the solution declined quickly. The alkaline flocculation of C. muelleri #862 was mainly attributed to the production of Mg(OH)2 rather than calcium phosphate or calcium hydroxide. For the strain S. quadricauda #507, the cells still existed integrally as normal cells after alkaline flocculation. Firstly, with the increasing of pH in the solution, the absolute value of zeta potential had not declined. When pH was around 10.8, the absolute value of zeta potential had declined abruptly and the solution conductivity was increasing all the time. The cell wall of S. quadricauda #507 with the high content of cellulose Iα and low crystallization degree was good for the next step of saccharification or oil extraction.

Uptake of Cadmium by the Green Alga Scenedesmus quadricauda in the Presence of Selenium Nanoparticles

Uptake of Cadmium by the Green Alga Scenedesmus quadricauda in the Presence of Selenium Nanoparticles

Impact of Anions, Cations, and pH on Manganese Accumulation and Toxicity in the Green Alga Scenedesmus quadricauda

Accumulation of divalent manganese (Mn) and its toxicity in the green alga Scenedesmus quadricauda was studied at circumneutral pH (6.5). A comparison of two applied concentrations (10 or 100 mu M) of MnCl2, MnSO4, and Mn(NO3)(2) indicated that mainly sulfate evoked higher Mn accumulation. On the other hand, nitrate rather depleted antioxidative enzyme activities (APX, CAT, SOD), leading to an increase in ROS formation as proven by fluorescence microscopy. Subsequent experiments revealed that increase in pH (from 4.5 to 9.5) increased also Mn content but typically depleted amounts of reduced glutathione and phytochelatin 2. We also measured the size of particles formed from the manganese salts at pH 9.5. Competitive experiment between Ca/K salts (CaCl2, CaSO4, Ca(NO3)(2), KCl, K2SO4, KNO3) and Mn (as Mn sulfate) showed a negative relation between Ca and Mn amount but KNO3 stimulated Mn accumulation. Microscopy revealed that mainly K salts elevated plasma membrane damage (Acridine orange staining). Data indicate that not only pH but also accompanying anion affects Mn accumulation and that Ca salts may affect Mn toxicity.

Study of the Toxicity of Distiller Fluid Ammonia-soda Production on Different Test Objects

The influence of distiller liquid – waste production of soda ash in the watercress Lepidium sativum, alga Scenedesmus quadricauda and the lowest crustaceans Daphnia magna is considered. It is shown that the various test objects differently react on distiller liquid. Harmless times of dilution is for watercress – 43, for algae – 130 and for lower crustacea – 150. To compare the toxic effects of various waste products on the test objects you must select one test object.

Dynamic modeling predicts continued bioaccumulation of polybrominated diphenyl ethers (PBDEs) in smallmouth bass (Micropterus dolomiu) post phase-out due to invasive prey and shifts in predation

Unprecedented food chain links between benthic and pelagic organisms are often thought to disrupt traditional contaminant transport and uptake due to changes in predation and mobilization of otherwise sequestered pollutants. A bioaccumulation model for polybrominated diphenyl ethers (PBDEs) is developed to simulate increases in biotic congener loads based upon trophic transfer through diet and gill uptake for a Lake Erie food chain including two invasive species as a benthic-pelagic link. The model utilizes species-specific bioenergetic parameters in a four-level food chain including the green alga Scenedesmus quadricauda, zebra mussels (Dreissena polymorpha), round goby (Appollonia melanostoma), and the smallmouth bass (Micropterus dolomiu). The model was calibrated to current biotic concentrations and predicts an increase in contaminant load by almost 48% in the upper trophic level in two years. Validation to archival data resulted in <2% error from reported values following a two-year simulation.

Effect of herbicides on photosynthetic electron transport and on the growth of the alga Scenedesmus quadricauda

The inhibitory effect of herbicides on the Hill reaction (with 2,6-dichloro-phenol-indophenol as acceptor) and their influence on development of the alga &lt;i&gt;Scenedesmus quadricauda&lt;/i&gt; was studied. The following herbicides were tested: 2,4-D, Gramoxone, Afalon, Kresamone, CIPC and Simazine. The results are discussed in terms of the mechanism of action of the investigated herbicides.

Physiology and methodology of chromium toxicity using alga Scenedesmus quadricauda as model object

Physiological responses of Scenedesmus quadricauda to Cr(VI) and Cr(III) excess were studied in buffer with circumneutral pH (6.5). Total Cr content was similar in low (1μM of both oxidation states) but higher in 10μM Cr(VI) treatment and high accumulation potential was detected (80–82% and 41–65% in 1 and 10μM treatments, respectively). Specific fluorescence indicator (6-((anthracen-9-yl) methyleneamino)-2H-chromen-2-one) confirmed partial reduction of Cr(VI) to Cr(III) under exposure conditions. Viability and chlorophyll autofluorescence were more depleted by Cr(VI) while Cr(III) stimulated increase in ROS and lipid peroxidation. Antioxidative enzyme activities showed significantly higher values in 10μM treatments of both Cr oxidation states. Depletion of mitochondrial proteins was not reflected in alteration of total soluble proteins indicating sensitivity of this organelle to Cr and TTC test showed no clear oxidation state-related effect. In this view, “Cr(VI) is not more toxic than Cr(III)” at least for some parameters. Subsequent study with the application of 10μM Cr(VI) confirmed that HEPES buffer is more suitable exposure solution for toxicological studied than water or inorganic salts (higher chlorophyll autofluorescence was observed) and pH 6.5 is more suitable than low or high pH (4.5 or 8.5) in terms of Cr uptake. Another known Cr(III) fluorescence indicator (naphthalimide–rhodamine) also confirmed partial reduction of Cr(VI) to Cr(III) at acidic pH but only traces were seen at alkaline pH.

Eco-toxicity of oily wastes containing TENORM

Oily wastes are considered as one of the most hazardous waste types. Additionally to petroleum components, they can contain radioactive elements. This study aimed to estimate the toxicity of four raw and two treated waste samples obtained from petroleum production yard. Eight elutriate bioassays using plants (Raphanus sativus and algae Scenedesmus quadricauda), crustacean (Daphnia magna and Thamnocephalus platyurus), rotifer (Brachionus calyciflorus), protozoa (Paramecium caudatum) and bacteria (Bacillus pumilus and luminescent commercial strain) were used. Two contact bioassays based on R. sativus and B. pumilus were applied. Total petroleum hydrocarbons (TPH) content and activity concentrations of radium, thorium and potassium were determined.