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1
Ando, A., M. Miwa, M. Kajino e S. Tatsumi. "Removal of Musty-Odorous Compounds in Water and Retained in Algal Cells through Water Purification Processes". Water Science and Technology 25, n. 2 (1 gennaio 1992): 299–306. http://dx.doi.org/10.2166/wst.1992.0065.
Testo completoAbstract (sommario):
Musty-odorous compounds, metabolites of some species of blue-green algae, are usually contained in both the water and algal cell bodies. The compounds in the latter solid phase were found to be easily removed by coagulation and sedimentation without breakpoint prechlorination (intermediate chlorination used instead). Chlorination of the algae results in an artificial release of the metabolite content into the surrounding water. When a large fraction of the compounds was present in the algal cell bodies, more than 60% of these compounds were removed in the intermediate-chlorination treatment. Powdered activated carbon treatment is effective in removing the compounds in the aqueous phase. However, the effectivness was usually limited in practical treatment to high concentrations of musty odor. On the other hand, the ozonation and granular activated carbon (GAC) treatment was found to be an effective method for removal. It was observed that the musty-odorous compounds were completely removed through the ozonation and GAC treatment system, which included coagulation and sedimentation without prechlorination.
2
Jorissen, Hendrikje, Christina Skinner, Ronald Osinga, Dirk de Beer e Maggy M. Nugues. "Evidence for water-mediated mechanisms in coral–algal interactions". Proceedings of the Royal Society B: Biological Sciences 283, n. 1836 (17 agosto 2016): 20161137. http://dx.doi.org/10.1098/rspb.2016.1137.
Testo completoAbstract (sommario):
Although many coral reefs have shifted from coral-to-algal dominance, the consequence of such a transition for coral–algal interactions and their underlying mechanisms remain poorly understood. At the microscale, it is unclear how diffusive boundary layers (DBLs) and surface oxygen concentrations at the coral–algal interface vary with algal competitors and competitiveness. Using field observations and microsensor measurements in a flow chamber, we show that coral (massive Porites ) interfaces with thick turf algae, macroalgae, and cyanobacteria, which are successful competitors against coral in the field, are characterized by a thick DBL and hypoxia at night. In contrast, coral interfaces with crustose coralline algae, conspecifics, and thin turf algae, which are poorer competitors, have a thin DBL and low hypoxia at night. Furthermore, DBL thickness and hypoxia at the interface with turf decreased with increasing flow speed, but not when thick turf was upstream. Our results support the importance of water-mediated transport mechanisms in coral–algal interactions. Shifts towards algal dominance, particularly dense assemblages, may lead to thicker DBLs, higher hypoxia, and higher concentrations of harmful metabolites and pathogens along coral borders, which in turn may facilitate algal overgrowth of live corals. These effects may be mediated by flow speed and orientation.
3
Wang, Di, Liling Xie, Xingbiao Zhu, Xiao Bi, Yuzhong Zheng e Yankun Zhu. "Study on the metabolites of DH-e, a Halomonas marine bacterium, against three toxic dinoflagellate species". Water Science and Technology 78, n. 7 (5 ottobre 2018): 1535–44. http://dx.doi.org/10.2166/wst.2018.426.
Testo completoAbstract (sommario):
Abstract Algicidal bacteria play an important role in mitigating harmful algal blooms (HABs). In the study, five bacterial strains were isolated from the East China Sea. One strain of algicidal bacterium, named DH-e, was found to selectively inhibit the motor ability of Prorocentrum donghaiense, Alexandrium tamarense (ATDH-47) and Karenia mikimotoi Hansen. Both 16S rDNA sequence analysis and morphological characteristics revealed that the algicidal DH-e bacterium belonged to Halomonas. Furthermore, results showed that the metabolites in the DH-e cell-free filtrate could kill algae directly, and the minimum inhibitory concentrations (MICs) of the bacterial metabolites on the cells of the three dinoflagellate species ranged from 35.0–70.0 μg/mL. Following short-term inhibitory tests, the dinoflagellates in mixed crude extract solution (0.7 mg/mL) ceased movement after 5 min. The algicidal mechanism of the metabolites was investigated through enzyme activities, including that of catalase (CAT), alkaline phosphatase (AKP), acetone peroxide (T-ATP) synthetase and nitrite reductase (NR). Results indicated that metabolites did not disrupt the energy or nutrient routes of the algae (P > 0.05), but did initiate an increase in free radicals in the algal cells, which might explain the subsequent death of sensitive algae. Thus, the metabolites of the DH-e bacterium showed promising potential for controlling HABs.
4
Xu, Qiuyang, Meixue Shi, Shaohua Wang e Yuchun Qing. "Study on the Effect of Exogenous Salicylic Acid on Algae Growth in the Environment". E3S Web of Conferences 165 (2020): 02001. http://dx.doi.org/10.1051/e3sconf/202016502001.
Testo completoAbstract (sommario):
With the development of industry, synthetic drugs and their secondary metabolites bring some hidden dangers to environmental safety. As an excellent drug, salicylic acid is widely used in cardiovascular drugs, industrial dyes, skin care and acne products, etc. Therefore, it is possible to detect salicylic acid molecules, its derivatives or secondary metabolites in the natural environment. It should be noted that salicylic acid, as an endogenous signal molecule, can greatly affect plant growth. In this study, the common algal Spirogyra in fresh water was taken as the research object. The effects of exogenous salicylic acid on the growth of Spirogyra were analyzed through the changes of chlorophyll content and plant cross section during the growth of Spirogyra. It is found that the concentration of salicylic acid in the natural environment generally promotes the development of algae and improves their resistance to environmental stress. Therefore, as a possible correlation index of algal blooms, it deserves our attention.
5
Ho, L., D. Hoefel, W. Aunkofer, T. Meyn, A. Keegan, J. Brookes, C. Saint e G. Newcombe. "Biological filtration for the removal of algal metabolites from drinking water". Water Supply 6, n. 2 (1 marzo 2006): 153–59. http://dx.doi.org/10.2166/ws.2006.064.
Testo completoAbstract (sommario):
Biological sand filters were assessed for their ability to remove geosmin, 2-methylisoborneol (MIB) and microcystin-LR. Microcystin-LR was the most readily degradable metabolite with a maximum lag period of only 5 days before it was undetected in the filter effluent. Geosmin and MIB were difficult to degrade, with a period in excess of 75 days before greater than 95% removal was achieved. A microcystin-degrading gene was detected in the biofilm from one of the filters, confirming that the biofilm possessed the ability to degrade microcystin. A Sphingomonas sp. was identified as a potential geosmin degrader based on denaturing gradient gel electrophoresis (DGGE) analysis. DGGE analysis revealed a more complex bacterial community during the degradation of MIB, suggesting that more than one bacterium may be responsible for its degradation.
6
Cotsaris, E., A. Bruchet, J. Mallevialle e D. B. Bursill. "The identification of odorous metabolites produced from algal monocultures". Water Science and Technology 31, n. 11 (1 giugno 1995): 251–58. http://dx.doi.org/10.2166/wst.1995.0443.
Testo completoAbstract (sommario):
Four algal species commonly found in the River Seine were cultured for a comprehensive investigation of their odorous metabolites. Closed loop stripping analysis (CLSA), open stripping analysis (OSA) and steam distillation extraction (SDE) were used to extract and concentrate a wide range of metabolites. The odour causing compounds were identified by a combination of chemical (gas chromatography-mass spectrometry (GC-MS)) and sensory (sensory-gas chromatography (sensory-GC), flavour profile analysis (FPA)) analyses. The compounds found responsible for unpleasant odours were alkenes, saturated and unsaturated aliphatic alcohols, aldehydes, ketones, sulphides and pyrazines. Some of the odorous compounds responsible for septic and muddy/musty odours may have been of bacterial or fungal origin as the cultures were non-axenic. Sensory-GC was found to be a valuable tool in identifying compounds of very low odour thresholds, which were present at or below the detection limits of the GC-MS.
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Dietrich, A. M., R. C. Hoehn, L. C. Dufresne, L. W. Buffin, D. M. C. Rashash e B. C. Parker. "Oxidation of odorous and nonodorous algal metabolites by permanganate, chlorine, and chlorine dioxide". Water Science and Technology 31, n. 11 (1 giugno 1995): 223–28. http://dx.doi.org/10.2166/wst.1995.0439.
Testo completoAbstract (sommario):
The six algal metabolites, at concentrations of 20-225 μg/l, were oxidized with potassium permanganate, chlorine, or chlorine dioxide at doses of 0.25-3 mg/l. Flavor profile analysis (FPA) was used to determine the odors of the solutions before and after oxidation. Linoleic and palmitic acids, which are odorless compounds, were oxidized to odorous products by all three oxidants. The odor intensity of β-cyclocitral (grape, sweet tobacco) and phenethyl alcohol (rose, floral) was only slightly decreased by any of the oxidants. Oxidation by permanganate or chlorine either eliminated or greatly reduced the odors associated with linolenic acid (watermelon) and 2t,6c-nonadienal (cucumber); chlorine dioxide was ineffective at reducing the cucumber odor of 2t,6c-nonadienal. Oxidation, at doses typically applied for drinking water treatment, can result in the destruction of certain algae-related odors but in the formation of other odors.
8
Dixon, M. B., C. Falconet, L. Ho, C. W. K. Chow, B. K. O'Neill e G. Newcombe. "Nanofiltration for the removal of algal metabolites and the effects of fouling". Water Science and Technology 61, n. 5 (1 marzo 2010): 1189–99. http://dx.doi.org/10.2166/wst.2010.903.
Testo completoAbstract (sommario):
Nanofiltration (NF) has been shown to be an effective way of removing organic micropollutants from drinking water due to its size exclusion properties. A rapid bench scale membrane test unit was utilised to trial six NF membranes to remove the algal metabolites, microcystin, cylindrospermopsin, 2-methylisoborneol (MIB) and geosmin (GSM). Membrane fouling due to the algal metabolites was observed for both charged and neutral metabolites. MIB and GSM were removed effectively by low molecular weight cut-off (MWCO) membranes but less effectively by a higher MWCO membrane. Removal of MIB and GSM by the higher MWCO membrane was improved as the membrane fouled. Microcystin was initially removed to above 90% by tight NF membranes but fouling of several membranes caused decreased percent removals over time. Tight NF membranes afforded removals of 90–100% for cylindrospermopsin, while removal by the higher MWCO membrane was lower but improved with time due to fouling.
9
Pereira, Leonel. "Seaweeds as Source of Bioactive Substances and Skin Care Therapy—Cosmeceuticals, Algotheraphy, and Thalassotherapy". Cosmetics 5, n. 4 (22 novembre 2018): 68. http://dx.doi.org/10.3390/cosmetics5040068.
Testo completoAbstract (sommario):
Riverine, estuarine, and coastal populations have always used algae in the development of home remedies that were then used to treat diverse health problems. The empirical knowledge of various generations originated these applications, and their mechanism of action is, in most cases, unknown, that is, few more scientific studies would have been described beyond simple collection and ethnographic recording. Nevertheless, recent investigations, carried out with the purpose of analyzing the components and causes that alter the functioning and the balance of our organism, are already giving their first results. Water, and especially sea water is considered as essential to life on our planet. It sings all the substances necessary and conducive to the development of the living being (minerals, catalysts, vitamins, amino acids, etc.). Oceans cover over 70% of Earth, being home to up to 90% of the organisms in the planet. Many rich resources and unique environments are provided by the ocean. Additionally, bioactive compounds that multiple marine organisms have a great potential to produce can be used as nutraceuticals, pharmaceuticals, and cosmeceuticals. Both primary and secondary metabolites are produced by algae. The first ones are directly implicated in development, normal growth, or reproduction conditions to perform physiological functions. Stress conditions, like temperature changes, salinity, environmental pollutants, or UV radiation exposure cause the performance of secondary metabolites. In algae, proteins, polysaccharides, fatty acids, and amino acids are primary metabolites and phenolic compounds, pigments, vitamins, sterols, and other bioactive agents, all produced in algae tissues, are secondary metabolites. These algal active constituents have direct relevance in cosmetics.
10
Munir, Mubashrah, Arshad Mahmood, Rahmatullah Qureshi, Sidra Murtaza e Mehmooda Munazir. "Preliminary Phytochemical Screening, Proximate Analysis, Antioxidant and Antibacterial Activities of an Algal Species of Hydrodictyon Reticulatum". Journal of Bioresource Management 7, n. 4 (31 dicembre 2020): 01–26. http://dx.doi.org/10.35691/jbm.0202.0147.
Testo completoAbstract (sommario):
The freshwater algae grow in a wide range of aquatic habitats across the globe and are rich in secondary metabolites. The present study was designed to conduct the phytochemical screening, proximate analysis, antioxidant and antibacterial activities of water net (Hydrodictyon reticulatum), an algal weed from Pakistan. The pure and dried algal mass was crushed into a fine powder and four solvent-based extracts were used for phytochemical screening. The results of preliminary qualitative screening indicated the presence of flavonoids, phenols, quinones, steroids, resins, anthraquinones, glycosides, lignin, proteins, saponins, tannins, reducing sugars, alkaloids, terpenoids, fats, and oils, whereas the quantification results revealed the high quantities of total ash, crude proteins, crude fiber, alkaloids, carotenoids, flavonoids, and chlorophyll a. The studied methanolic extracts with maximum concentration (150 μg/ml) showed significantly (p-value ≤ 0.05) higher antioxidant and antibacterial activities. The IC50 values of the crude methanolic extract of water net were found very close to streptomycin (positive control) against both bacterial pathogenic species of Klebsiella pneumoniae and Staphylococcus aureus. This study concluded that the crude extracts of water net possessed antibacterial activity at par to streptomycin drug, and requires further detailed study for the separation, identification, and testing of the pure phytochemical compound to be used by the nutraceutical and or pharmaceutical industry.
11
Roh, S. H., D. H. Kwak, H. J. Jung, K. J. Hwang, I. H. Baek, Y. N. Chun, S. I. Kim e J. W. Lee. "Simultaneous Removal of Algae and Their Secondary Algal Metabolites from Water by Hybrid System of DAF and PAC Adsorption". Separation Science and Technology 43, n. 1 (gennaio 2008): 113–31. http://dx.doi.org/10.1080/01496390701764494.
Testo completo
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ten Veldhuis, Marie-Claire, Gennady Ananyev e G. Charles Dismukes. "Symbiosis extended: exchange of photosynthetic O2 and fungal-respired CO2 mutually power metabolism of lichen symbionts". Photosynthesis Research 143, n. 3 (31 dicembre 2019): 287–99. http://dx.doi.org/10.1007/s11120-019-00702-0.
Testo completoAbstract (sommario):
AbstractLichens are a symbiosis between a fungus and one or more photosynthetic microorganisms that enables the symbionts to thrive in places and conditions they could not compete independently. Exchanges of water and sugars between the symbionts are the established mechanisms that support lichen symbiosis. Herein, we present a new linkage between algal photosynthesis and fungal respiration in lichen Flavoparmelia caperata that extends the physiological nature of symbiotic co-dependent metabolisms, mutually boosting energy conversion rates in both symbionts. Measurements of electron transport by oximetry show that photosynthetic O2 is consumed internally by fungal respiration. At low light intensity, very low levels of O2 are released, while photosynthetic electron transport from water oxidation is normal as shown by intrinsic chlorophyll variable fluorescence yield (period-4 oscillations in flash-induced Fv/Fm). The rate of algal O2 production increases following consecutive series of illumination periods, at low and with limited saturation at high light intensities, in contrast to light saturation in free-living algae. We attribute this effect to arise from the availability of more CO2 produced by fungal respiration of photosynthetically generated sugars. We conclude that the lichen symbionts are metabolically coupled by energy conversion through exchange of terminal electron donors and acceptors used in both photosynthesis and fungal respiration. Algal sugars and O2 are consumed by the fungal symbiont, while fungal delivered CO2 is consumed by the alga.
13
Kapkov, V. I., S. G. Vasilieva e E. S. Lobakova. "SUCCESSION OF CYANOBACTERIA IN BOREAL WATERS". Journal of microbiology epidemiology immunobiology, n. 4 (28 agosto 2018): 100–107. http://dx.doi.org/10.36233/0372-9311-2018-4-100-107.
Testo completoAbstract (sommario):
The in situ investigation of cyanobacterial seasonal succession, causing algal «blooms» in boreal waters, and its dependence on ecological factors was fulfilled. It was revealed that the most important abiotic factors promoting the growth and changes of dominant species in populations are the water temperature, the level of solar radiation and content of cyanobacterial metabolites. The most profound «blooming» with highest biomass and toxic metabolites accumulation occurs during anticyclone type of weather. During such periods cyanobacteria are the most prevalent cultures due to the combination of adaptive mechanisms acquired in evolutionary process which other partners of planktonic community lacked or deprived. It was hypotized that the global warming and cyanobacteria ability to inhabit different biotopes due to environmental tolerance would result in more profound and prolonged «blooming» of boreal waters.
14
Whitfield, F. B. "Chemistry of Off-Flavours in Marine Organisms". Water Science and Technology 20, n. 8-9 (1 agosto 1988): 63–74. http://dx.doi.org/10.2166/wst.1988.0226.
Testo completoAbstract (sommario):
Edible marine and fresh-water organisms are occasionally affected by off-flavours and taints. In coastal and estuarine areas near industrial sites the contamination is usually by compounds of industrial origin. However, unpolluted environments can also be a source of off-flavour compounds. For example, earthy/muddy off-flavours are caused by bioaccumulation of metabolites produced during algal blooms. Recent studies have also shown that garlic and iodoform-1ike off-flavours in marine crustacea are caused by compounds which can occur naturally in algae, bryozoa and debris. Compounds derived from these sources include the extremely potent trimethylarsine, 2-bromophenol and 2,6-dibromophenol. This paper examines the biological origins of such compounds, including their possible production from non-odorous precursors, and discusses their chemistry with special reference to their identification, quantitative analysis and sensory properties.
15
Zhao, Min, Han Xiao, Dong Sun e Shunshan Duan. "Investigation of the Inhibitory Effects of Mangrove Leaves and Analysis of Their Active Components on Phaeocystis globosa during Different Stages of Leaf Age". International Journal of Environmental Research and Public Health 15, n. 11 (1 novembre 2018): 2434. http://dx.doi.org/10.3390/ijerph15112434.
Testo completoAbstract (sommario):
The presence of harmful algal blooms (HABs) can cause significant problems to the quality of the water, the marine ecosystems, and the human health, and economy worldwide. Biological remediation can inhibit harmful algal growth efficiently in an environmental-friendly manner. Therefore, the research conducted on biological remediation with regard to the inhibition of HABs is becoming a major focus in marine ecology. To date, no study has been reported with regard to the red tides occurring in mangrove wetlands. Therefore, the present study used two mangrove species, namely Bruguiera gymnorrhiza and Kandelia candel and one harmful algae species Phaeocystis globosa as experimental organisms. The present study determined the inhibitory effects and algae physiology of specific aqueous extracts from mangrove leaves on the viability of harmful algae, and analyzed the main chemical composition of the aqueous extracts by ultra-performance liquid chromatography coupled to high resolution mass spectrometry (UPLC-QTOF-MS). The results indicated that the aqueous extracts from different leaf ages of B. gymnorrhiza and K. candel leaves exhibited apparent inhibitory effects on the growth of P. globosa. The inhibitory effects of B. gymnorrhiza and K. candel leaves aqueous extracts on the growth of P. globosa were in the following order: senescent > mature > young leaves. The levels of the parameters superoxide dismutase (SOD) activity, glutathione (GSH), and malondialdehyde (MDA)content in P. globosa following treatment with B. gymnorrhiza and K. candel leaves aqueous extracts were increased as follows: senescent > mature > young leaves. Simultaneously, the intensity of the ion peaks of the specific secondary metabolites assigned 4 (No.: 4 Rt: 2.83 min), 7 (No.: 7 Rt: 3.14 min), 8 (No.: 8 Rt: 3.24 min), 9 (No.: 9 Rt: 3.82min) and 10 (No.: 10 Rt: 4.10 min) were increased. These metabolites were found in the aqueous extracts from B. gymnorrhiza leaves. The intensities of the ion peaks of the secondary metabolites 7, 8 in the aqueous extracts from the K. candel leaves were also increased. The majority of the substances that inhibited the algae found in the mangrove plants were secondary metabolites. Therefore, we considered that the norsesquiterpenes compounds 4, 8, 9, and 10 and a phenolic glycoside compound 7 were the active constituents in the aqueous extracts of the mangrove leaves responsible for the inhibition of algae growth. This evidence provided theoretical guidance for the development of biological methods to control red tides and for the further use of substances with antiproliferative activity against algae.
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S, Princely, e Dhanaraju Md. "ASSESSMENT OF PHYTOCHEMICAL CONSTITUENTS, IN VITRO ANTIMICROBIAL AND ANTIOXIDANT POTENTIAL OF ULVA EXTRACTS FROM VISHAKHAPATNAM COAST". Asian Journal of Pharmaceutical and Clinical Research 10, n. 8 (1 agosto 2017): 87. http://dx.doi.org/10.22159/ajpcr.2017.v10i8.18582.
Testo completoAbstract (sommario):
Objective: Antimicrobial drug resistance is the foremost problem faced worldwide with the current antibiotic therapy in treating infectious diseases. Marine algae were considered as a potential source of biologically active compounds with antibacterial, antifungal, antiviral, and anticancer activities.Materials and Methods: In the present investigation, the purified fractions of marine algal crude extracts of different solvents such as aqueous, ethyl acetate (EtAc), and ethanol for antioxidant (1,1-diphenyl-2-picrylhydrazyl radical scavenging assay) and antimicrobial activities (agar well diffusion assay) were evaluated.Results: The extracts of EtAc, ethanol, and water showed minimum inhibitory concentration values of 3.125, 6.25, and 12.25 μg/ml, respectively, for tested bacterial pathogens. The active fractions showed very little activity against Klebsiella pneumonia and Salmonella Typhi, and no activity was observed against Pseudomonas aeruginosa. The results of our screening showed that the EtAc marine algal fractions were active against some Gram-positive, Gram-negative bacteria and Candida albicans. The phytochemical analysis of aqueous, ethanolic, and EtAc extracts of marine algae showed the presence of the various phytochemical constituents such as carbohydrates, phenols, and amino acids. The ethanolic extracts showed the highest antioxidant activity as compared to aqueous and EtAc extracts.Conclusion: This work can be extended further to isolate, characterize, and discover more bioactive metabolites from marine algae, which can be exploited for the production of lead molecules in pharmaceuticals for the treatment of chronic diseases.
17
Li, Yueying, C. Benjamin Naman, Kelsey L. Alexander, Huashi Guan e William H. Gerwick. "The Chemistry, Biochemistry and Pharmacology of Marine Natural Products from Leptolyngbya, a Chemically Endowed Genus of Cyanobacteria". Marine Drugs 18, n. 10 (6 ottobre 2020): 508. http://dx.doi.org/10.3390/md18100508.
Testo completoAbstract (sommario):
Leptolyngbya, a well-known genus of cyanobacteria, is found in various ecological habitats including marine, fresh water, swamps, and rice fields. Species of this genus are associated with many ecological phenomena such as nitrogen fixation, primary productivity through photosynthesis and algal blooms. As a result, there have been a number of investigations of the ecology, natural product chemistry, and biological characteristics of members of this genus. In general, the secondary metabolites of cyanobacteria are considered to be rich sources for drug discovery and development. In this review, the secondary metabolites reported in marine Leptolyngbya with their associated biological activities or interesting biosynthetic pathways are reviewed, and new insights and perspectives on their metabolic capacities are gained.
18
Sukenik, Assaf, e Aaron Kaplan. "Cyanobacterial Harmful Algal Blooms in Aquatic Ecosystems: A Comprehensive Outlook on Current and Emerging Mitigation and Control Approaches". Microorganisms 9, n. 7 (9 luglio 2021): 1472. http://dx.doi.org/10.3390/microorganisms9071472.
Testo completoAbstract (sommario):
An intensification of toxic cyanobacteria blooms has occurred over the last three decades, severely affecting coastal and lake water quality in many parts of the world. Extensive research is being conducted in an attempt to gain a better understanding of the driving forces that alter the ecological balance in water bodies and of the biological role of the secondary metabolites, toxins included, produced by the cyanobacteria. In the long-term, such knowledge may help to develop the needed procedures to restore the phytoplankton community to the pre-toxic blooms era. In the short-term, the mission of the scientific community is to develop novel approaches to mitigate the blooms and thereby restore the ability of affected communities to enjoy coastal and lake waters. Here, we critically review some of the recently proposed, currently leading, and potentially emerging mitigation approaches in-lake novel methodologies and applications relevant to drinking-water treatment.
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Bruchet, A., e J. P. Duguet. "Role of oxidants and disinfectants on the removal, masking and generation of tastes and odours". Water Science and Technology 49, n. 9 (1 maggio 2004): 297–306. http://dx.doi.org/10.2166/wst.2004.0589.
Testo completoAbstract (sommario):
This paper summarises the positive and negative effects of the most commonly used oxidants and disinfectants: chlorine, chloramines, chlorine dioxide, potassium permanganate ozone, and advanced oxidation with ozone/hydrogen peroxide on tastes and odours present in natural and drinking waters. The case studies reported illustrate the generation of odorous by-products such as chlorophenols, iodoforms, aldehydes, the masking effect between earthy-musty and chlorinous odours, and the removal of odorous algal metabolites or anthropogenic pollutants by ozone alone or by ozone coupled with hydrogen peroxide.
20
Potocki, Leszek, Bernadetta Oklejewicz, Ewelina Kuna, Ewa Szpyrka, Magdalena Duda e Janusz Zuczek. "Application of Green Algal Planktochlorella nurekis Biomasses to Modulate Growth of Selected Microbial Species". Molecules 26, n. 13 (1 luglio 2021): 4038. http://dx.doi.org/10.3390/molecules26134038.
Testo completoAbstract (sommario):
As microalgae are producers of proteins, lipids, polysaccharides, pigments, vitamins and unique secondary metabolites, microalgal biotechnology has gained attention in recent decades. Microalgae can be used for biomass production and to obtain biotechnologically important products. Here, we present the application of a method of producing a natural, biologically active composite obtained from unicellular microalgae of the genus Planktochlorella sp. as a modulator of the growth of microorganisms that can be used in the cosmetics and pharmaceutical industries by exploiting the phenomenon of photo-reprogramming of metabolism. The combination of red and blue light allows the collection of biomass with unique biochemical profiles, especially fatty acid composition (Patent Application P.429620). The ethanolic and water extracts of algae biomass inhibited the growth of a number of pathogenic bacteria, namely Enterococcus faecalis, Staphylococcus aureus PCM 458, Streptococcus pyogenes PCM 2318, Pseudomonas aeruginosa, Escherichia coli PCM 2209 and Candida albicans ATCC 14053. The algal biocomposite obtained according to our procedure can be used also as a prebiotic supplement. The presented technology may allow the limitation of the use of antibiotics and environmentally harmful chemicals commonly used in preparations against Enterococcus faecalis, Staphylococcus aureus, Streptococcus pyogenes, Pseudomonas aeruginosa, Escherichia coli or Candida spp.
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Kureyshevich, A. V., V. P. Guseynova e A. I. Sakevich. "Influence of Algal Metabolites on the Quality of Water Depending on the Action of Natural and Anthropic Factors". Hydrobiological Journal 40, n. 2 (2004): 51–65. http://dx.doi.org/10.1615/hydrobj.v40.i2.60.
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Klintzsch, Thomas, Gerald Langer, Gernot Nehrke, Anna Wieland, Katharina Lenhart e Frank Keppler. "Methane production by three widespread marine phytoplankton species: release rates, precursor compounds, and potential relevance for the environment". Biogeosciences 16, n. 20 (28 ottobre 2019): 4129–44. http://dx.doi.org/10.5194/bg-16-4129-2019.
Testo completoAbstract (sommario):
Abstract. Methane (CH4) production within the oceanic mixed layer is a widespread phenomenon, but the underlying mechanisms are still under debate. Marine algae might contribute to the observed CH4 oversaturation in oxic waters, but so far direct evidence for CH4 production by marine algae has only been provided for the coccolithophore Emiliania huxleyi. In the present study we investigated, next to E. huxleyi, other widespread haptophytes, i.e., Phaeocystis globosa and Chrysochromulina sp. We performed CH4 production and stable carbon isotope measurements and provide unambiguous evidence that all three investigated marine algae are involved in the production of CH4 under oxic conditions. Rates ranged from 1.9±0.6 to 3.1±0.4 µg of CH4 per gram of POC (particulate organic carbon) per day, with Chrysochromulina sp. and E. huxleyi showing the lowest and highest rates, respectively. Cellular CH4 production rates ranged from 16.8±6.5 (P. globosa) to 62.3±6.4 ag CH4 cell−1 d−1 (E. huxleyi; ag = 10−18 g). In cultures that were treated with 13C-labeled hydrogen carbonate, δ13CH4 values increased with incubation time, resulting from the conversion of 13C–hydrogen carbonate to 13CH4. The addition of 13C-labeled dimethyl sulfide, dimethyl sulfoxide, and methionine sulfoxide – known algal metabolites that are ubiquitous in marine surface layers – resulted in the occurrence of 13C-enriched CH4 in cultures of E. huxleyi, clearly indicating that methylated sulfur compounds are also precursors of CH4. By comparing the algal CH4 production rates from our laboratory experiments with results previously reported in two field studies of the Pacific Ocean and the Baltic Sea, we might conclude that algae-mediated CH4 release is contributing to CH4 oversaturation in oxic waters. Therefore, we propose that haptophyte mediated CH4 production could be a common and important process in marine surface waters.
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Wang, Shuhang, Wenwen Wang, Junyi Chen, Bo Zhang, Li Zhao e Xia Jiang. "Characteristics of Dissolved Organic Matter and Its Role in Lake Eutrophication at the Early Stage of Algal Blooms—A Case Study of Lake Taihu, China". Water 12, n. 8 (13 agosto 2020): 2278. http://dx.doi.org/10.3390/w12082278.
Testo completoAbstract (sommario):
Decaying algal blooms in eutrophic lakes can introduce organic matter into the water and change nutrient concentrations in the water column. The spatial distribution and composition characteristics, sources, and contribution to eutrophication of dissolved organic matter (DOM) in the overlying water of Lake Taihu, a typical eutrophic lake in China, were analyzed by ultraviolet–visible spectra and three-dimensional fluorescence excitation–emission matrix spectra combined with the statistical decomposition technique, parallel factor analysis. The concentration of DOM was represented by dissolved organic carbon (DOC), and DOC in overlying water of Lake Taihu was 2.86–11.83 mg/L. The colored DOM (CDOM) was characterized by an absorption coefficient at 280 nm (a280) and 350 nm (a350), which were 6.63–29.87 and 1.84–10.41 m−1, respectively. These values showed an increasing trend from southeast to northwest, and the high values were concentrated in the northwest and northern lake areas. The parallel factor analysis (PARAFAC) identified two protein-like (C1: tyrosine-like and C2: tryptophan-like) and one humic-like (C3: humic acid and fulvic acid) fluorescence components for fluorescent DOM (FDOM). The most dominant components were protein-like components (C1 + C2), whose fluorescence intensity contributed 87.55% ± 3.39% to the total fluorescence intensity (Ft) of FDOM (3.38 R.U.). The mean value of the fluorescence index (FI) and index of recent autochthonous contribution (BIX) of DOM was 1.77 and 0.92, and DOC, a280 and fluorescence intensities of FDOM components were all significantly and positively correlated with chl. a, indicating that DOM, CDOM, and FDOM were all mainly derived from algal activities and metabolites. The average humification index of the DOM was 0.66, which indicated a low humification degree. The protein-like DOM was correlated with DON and DOP, and might make great contributions to the continuous occurrence of algal blooms.
24
Bartual, Ana, e María J. Ortega. "Temperature differentially affects the persistence of polyunsaturated aldehydes in seawater". Environmental Chemistry 10, n. 5 (2013): 403. http://dx.doi.org/10.1071/en13055.
Testo completoAbstract (sommario):
Environmental context Diatoms, unicellular algae that live suspended in the water column, can undergo periods of rapid growth, called blooms. When these algal blooms die, organic compounds including polyunsaturated aldehydes are released to the surrounding water with currently unknown ecological effects. Here we demonstrate that temperature differentially affects the persistence of three major polyunsaturated aldehydes produced by diatoms, and we quantify the removal rates from seawater of these compounds. Abstract Polyunsaturated aldehydes (PUAs) are volatile compounds commonly released into the environment by different fresh and seawater phytoplankton species. Diatoms are among the main producers of these metabolites in seawater. The release of these metabolites in seawater is known to be wound-activated as a consequence of predation or cell lysis. Hence, the interaction of phytoplankton species that produce PUAs with other marine organisms is being thoroughly investigated. However, the stability of these compounds in seaweater once they are released and their persistence under different environmental conditions have never been quantified. In this work, we reveal an important effect of seawater temperature on the persistence of dissolved 2E,4E/Z-decadienal (DECA), 2E,4E/Z-octadienal (OCTA) and 2E,4E/Z-heptadienal (HEPTA) in seawater at the nanomolar scale. These three aldehydes were more persistent at 10°C than at either 15 or 20°C. Half lives of OCTA and HEPTA were reduced from 200h at 10°C to 80h at 15°C and 60h at 20°C. In addition, DECA was consistently more persistent than OCTA and HEPTA at the three temperatures assayed. This dependence of the persistence of dissolved PUAs on seawater temperature could determine a differential effect of equivalent PUA concentrations on the diversity and plankton community’s structure at different water depths, seasons or latitudes.
25
O'Rourke, Rachel, Mark Gaffney e Richard Murphy. "The effects of Parachlorella kessleri cultivation on brewery wastewater". Water Science and Technology 73, n. 6 (10 dicembre 2015): 1401–8. http://dx.doi.org/10.2166/wst.2015.618.
Testo completoAbstract (sommario):
Bioindustrial wastewaters, often characterised by high carbon and nitrogen contents, have shown promise as a valuable resource for the cultivation of beneficial microorganisms. The purpose of this study was to assess if Parachlorella kessleri could utilise brewery wastewater (Br WW) for growth and production of metabolites. P. kessleri was cultivated on different concentrations of Br WW over 14 days. Higher concentrations of Br WW led to an approximate two-fold increase in dry cell weight yielding a maximum of 12.3 g DCW/L. High glucose and nitrogen utilisation was associated with high algal biomass yields, with a 97% reduction in glucose achieved in 50% (v/v) Br WW cultures after 14 days. Assessing the benefits to P. kessleri, increases in oleic and α-linoleic acids were seen in 50 and 10% (v/v) Br WW cultures. Concentration of Br WW did not have an impact on the overall antioxidant activities of microalgal cultures, however, it did affect phenolic levels (2.4-fold increase) in 50% (v/v) Br WW cultures. This research demonstrated that P. kessleri did utilise the carbon and nitrogen content in the Br WW for growth and metabolite production, thereby reducing the nutrient load of the Br WW.
26
Ayele, Abate, Deribe Getachew, M. Kamaraj e A. Suresh. "Phycoremediation of Synthetic Dyes: An Effective and Eco-Friendly Algal Technology for the Dye Abatement". Journal of Chemistry 2021 (19 maggio 2021): 1–14. http://dx.doi.org/10.1155/2021/9923643.
Testo completoAbstract (sommario):
Rapid industrialization leads to serious environmental hazards due to the increase in the release of pollutants into the environment. Industries that use synthetic dyes for different applications are a predominant source for dye contaminants by releasing the dye in wastewater with pretreatment or without treatment directly into the water bodies, making serious water pollution in the environment. Therefore, it is imperative to safeguard the environment from such contaminants and their associated negative impacts. The conventional treatment method that is used to treat dye-contaminated wastewater is generally costly and has a possibility to produce secondary metabolites. Due to the above problems, the biological method is preferable to treat effluent or dye-contaminated wastewater. Phycoremediation is an algae-based eco-friendly dye abatement technique from contaminated environments. This review highlights the phycoremediation of dyes and its underlying mechanisms along with the information on synthetic dyes, classification, hazardous effects, and other major techniques of dye abatement. This review provides a comprehensive insight into several influencing factors such as pH, temperature, contact time, the dose of algae biomass, and agitation speed, as well as functional groups involved in the phycoremediation process.
27
McNabb, Paul, Andrew I. Selwood, Patrick T. Holland, J. Aasen, T. Aune, G. Eaglesham, P. Hess et al. "Multiresidue Method for Determination of Algal Toxins in Shellfish: Single-Laboratory Validation and Interlaboratory Study". Journal of AOAC INTERNATIONAL 88, n. 3 (1 maggio 2005): 761–72. http://dx.doi.org/10.1093/jaoac/88.3.761.
Testo completoAbstract (sommario):
Abstract A method that uses liquid chromatography with tandem mass spectrometry (LC/MS/MS) has been developed for the highly sensitive and specific determination of amnesic shellfish poisoning toxins, diarrhetic shellfish poisoning toxins, and other lipophilic algal toxins and metabolites in shellfish. The method was subjected to a full single-laboratory validation and a limited interlaboratory study. Tissue homogenates are blended with methanol-water (9 + 1), and the centrifuged extract is cleaned up with a hexane wash. LC/MS/MS (triple quadrupole) is used for quantitative analysis with reversed-phase gradient elution (acidic buffer), electrospray ionization (positive and negative ion switching), and multiple-reaction monitoring. Ester forms of dinophysis toxins are detected as the parent toxins after hydrolysis of the methanolic extract. The method is quantitative for 6 key toxins when reference standards are available: azaspiracid-1 (AZA1), domoic acid (DA), gymnodimine (GYM), okadaic acid (OA), pectenotoxin-2 (PTX2), and yessotoxin (YTX). Relative response factors are used to estimate the concentrations of other toxins: azaspiracid-2 and -3 (AZA2 and AZA3), dinophysis toxin-1 and -2 (DTX1 and DTX2), other pectenotoxins (PTX1, PTX6, and PTX11), pectenotoxin secoacid metabolites (PTX2-SA and PTX11-SA) and their 7-epimers, spirolides, and homoYTX and YTX metabolites (45-OHYTX and carboxyYTX). Validation data have been gathered for Greenshell mussel, Pacific oyster, cockle, and scallop roe via fortification and natural contamination. For the 6 key toxins at fortification levels of 0.05–0.20 mg/kg, recoveries were 71–99% and single laboratory reproducibilities, relative standard deviations (RSDs), were 10–24%. Limits of detection were <0.02 mg/kg. Extractability data were also obtained for several toxins by using successive extractions of naturally contaminated mussel samples. A preliminary interlaboratory study was conducted with a set of toxin standards and 4 mussel extracts. The data sets from 8 laboratories for the 6 key toxins plus DTX1 and DTX2 gave within-laboratories repeatability (RSDr) of 8–12%, except for PTX-2. Between-laboratories reproducibility (RSDR) values were compared with the Horwitz criterion and ranged from good to adequate for 7 key toxins (HorRat values of 0.8–2.0).
28
Rawn, Dorothea F. K., Benjamin P.-Y. Lau, Barbara Niedzwiadek e James F. Lawrence. "Improved Method for the Determination of Anatoxin-a and Two of Its Metabolites in Blue-Green Algae Using Liquid Chromatography with Fluorescence Detection". Journal of AOAC INTERNATIONAL 88, n. 6 (1 settembre 2005): 1741–47. http://dx.doi.org/10.1093/jaoac/88.6.1741.
Testo completoAbstract (sommario):
Abstract Anatoxin-a, a neurotoxin produced by blue-green algae (BGA) species, can cause death to exposed organisms. In North America, BGA are harvested and sold as food supplements, some of which contain elevated levels of other algal toxins, such as microcystins. Concern that elevated levels of anatoxin-a also may be present in BGA food supplements has led to the development of a simple method to determine the presence of anatoxin-a in BGA. Some researchers have successfully analyzed this compound using liquid chromatography with fluorescence detection by forming a fluorescent derivative with 4-fluoro-7-nitrobenzofurazan (NBD-F) in water and phytoplankton extracts. With this method, the background noise is high in BGA extracts due to the presence of co-extractives. Addition of o-phthaldialdehyde (OPA) and mercaptoethanol to the extract before addition of the NBD-F resulted in the successful removal of primary amines from the background noise when the NBD-F derivatives were detected with fluorescence. Improved chromatograms were obtained when extracts were cleaned up in this manner, leading to a lower detection limit (approximately 50 μg/kg) for anatoxin-a. The detection limits obtained for the 2 degradation products dihydroanatoxin-a and epoxyanatoxin-a in BGA extracts were similarly low (55 and 65 μg/kg, respectively).
29
Ismail, Mona M., Badriyah S. Alotaibi e Mostafa M. EL-Sheekh. "Therapeutic Uses of Red Macroalgae". Molecules 25, n. 19 (25 settembre 2020): 4411. http://dx.doi.org/10.3390/molecules25194411.
Testo completoAbstract (sommario):
Red Seaweed “Rhodophyta” are an important group of macroalgae that include approximately 7000 species. They are a rich source of structurally diverse bioactive constituents, including protein, sulfated polysaccharides, pigments, polyunsaturated fatty acids, vitamins, minerals, and phenolic compounds with nutritional, medical, and industrial importance. Polysaccharides are the main components in the cell wall of red algae and represent about 40–50% of the dry weight, which are extensively utilized in industry and pharmaceutical compounds, due to their thickening and gelling properties. The hydrocolloids galactans carrageenans and agars are the main red seaweed cell wall polysaccharides, which had broad-spectrum therapeutic characters. Generally, the chemical contents of seaweed are different according to the algal species, growth stage, environment, and external conditions, e.g., the temperature of the water, light intensity, nutrient concentrations in the ecosystem. Economically, they can be recommended as a substitute source for natural ingredients that contribute to a broad range of bioactivities like cancer therapy, anti-inflammatory agents, and acetylcholinesterase inhibitory. This review touches on the main points of the pharmaceutical applications of red seaweed, as well as the exploitation of their specific compounds and secondary metabolites with vital roles.
30
Tsuchiya, Y., e A. Matsumoto. "Identification of Volatile Metabolites Produced by Blue-Green Algae". Water Science and Technology 20, n. 8-9 (1 agosto 1988): 149–55. http://dx.doi.org/10.2166/wst.1988.0236.
Testo completoAbstract (sommario):
Some of the volatile metabolites of eight species of blue-green algae of the genera Oscillatoria, Phormidium, Aphanizomenon, and Anabaena were identified by gas chromatography mass spectrometry (GC-MS). As a result, five sesquiterpene alcohols (C15H26O) and two sesquiterpene hydrocarbons (germacrene-D and γ-cadi-nene) were detected in the cultures of Oscillatoriasplendida. O. amoena, and Anabaenamacrospora. Three aliphatic hydrocarbons (n-heptadecane,1-heptadecene and 7-methylheptadecane) were also identified in the cultures of most of these algae. None of these compounds appeared to impart an unpleasant taste or odor to water supplies.
31
Moradinejad, Saber, Caitlin M. Glover, Jacinthe Mailly, Tahere Zadfathollah Seighalani, Sigrid Peldszus, Benoit Barbeau, Sarah Dorner, Michèle Prévost e Arash Zamyadi. "Using Advanced Spectroscopy and Organic Matter Characterization to Evaluate the Impact of Oxidation on Cyanobacteria". Toxins 11, n. 5 (17 maggio 2019): 278. http://dx.doi.org/10.3390/toxins11050278.
Testo completoAbstract (sommario):
Drinking water treatment plants throughout the world are increasingly facing the presence of toxic cyanobacteria in their source waters. During treatment, the oxidation of cyanobacteria changes cell morphology and can potentially lyse cells, releasing intracellular metabolites. In this study, a combination of techniques was applied to better understand the effect of oxidation with chlorine, ozone, potassium permanganate, and hydrogen peroxide on two cell cultures (Microcystis, Dolichospermum) in Lake Champlain water. The discrepancy observed between flow cytometry cell viability and cell count numbers was more pronounced for hydrogen peroxide and potassium permanganate than ozone and chlorine. Liquid chromatography with organic carbon and nitrogen detection was applied to monitor the changes in dissolved organic matter fractions following oxidation. Increases in the biopolymer fraction after oxidation with chlorine and ozone were attributed to the release of intracellular algal organic matter and/or fragmentation of the cell membrane. A novel technique, Enhanced Darkfield Microscopy with Hyperspectral Imaging, was applied to chlorinated and ozonated samples. Significant changes in the peak maxima and number of peaks were observed for the cell walls post-oxidation, but this effect was muted for the cell-bound material, which remained relatively unaltered.
32
Kambourova, Roumena, Vassya Bankova e Georgi Petkov. "Volatile Substances of the Green Alga Scenedesmus incrassatulus". Zeitschrift für Naturforschung C 58, n. 3-4 (1 aprile 2003): 187–90. http://dx.doi.org/10.1515/znc-2003-3-408.
Testo completoAbstract (sommario):
Volatile substances of the green microalga Scenedesmus incrassatulus, cultivated in fresh and salt water, were studied. Cultivation in fresh water diversifies volatile secondary metabolites. Hydrocarbons and derivatives of the acetate pathway predominate when algae are grown in salt water; isoprenoids and aromatics are more abundant after fresh water cultivation.
33
He, Chen, Wu, Sun, Ma, Wang, Liu, Chen e Wang. "Distribution Characteristics and Environmental Control Factors of Lipophilic Marine Algal Toxins in Changjiang Estuary and the Adjacent East China Sea". Toxins 11, n. 10 (12 ottobre 2019): 596. http://dx.doi.org/10.3390/toxins11100596.
Testo completoAbstract (sommario):
Marine algal toxins, highly toxic secondary metabolites, have significant influences on coastal ecosystem health and mariculture safety. The occurrence and environmental control factors of lipophilic marine algal toxins (LMATs) in the surface seawater of the Changjiang estuary (CJE) and the adjacent East China Sea (ECS) were investigated. Pectenotoxin-2 (PTX2), okadaic acid (OA), dinophysistoxin-1(DTX1), and gymnodimine (GYM) were detected in the CJE surface seawater in summer, with concentration ranges of not detected (ND)–105.54 ng/L, ND–13.24 ng/L, ND–5.48 ng/L, and ND–12.95 ng/L, respectively. DTX1 (ND–316.15 ng/L), OA (ND–16.13 ng/L), and PTX2 (ND–4.97 ng/L) were detected in the ECS during spring. LMATs formed a unique low-concentration band in the Changjiang diluted water (CJDW) coverage area in the typical large river estuary. PTX2, OA, and DTX1 in seawater were mainly derived from Dinophysis caudate and Dinophysis rotundata, while GYM was suspected to be from Karenia selliformis. Correlation analyses showed that LMAT levels in seawater were positively correlated with dissolved oxygen and salinity, but negatively correlated with temperature and nutrients, indicating that the hydrological condition and nutritional status of seawater and climatic factors exert significant effects on the distribution of LMATs.
34
Watson, Susan B., Jeff Ridal e Gregory L. Boyer. "Taste and odour and cyanobacterial toxins: impairment, prediction, and management in the Great Lakes". Canadian Journal of Fisheries and Aquatic Sciences 65, n. 8 (agosto 2008): 1779–96. http://dx.doi.org/10.1139/f08-084.
Testo completoAbstract (sommario):
This paper reviews the issues associated with algal–cyanobacterial taste–odour (T&O) compounds and toxins in the Great Lakes. As with other remediated water bodies, the Great Lakes have undergone significant shifts in nutrient and food-web regimes and are exhibiting erratic blooms and noxious algal metabolite (NAM) outbreaks, despite reduced offshore nutrient levels. We appraise the chemistry, biota, and distribution of NAM impairments and conclude that management strategies based on lakewide monitoring and remedial action plans are often unsuccessful because they attempt NAM control through an unsustainable reliance on water treatment and broad-scale nutrient–biomass models. This approach is undermined by several factors: (i) only some species produce NAMs; (ii) different taxa show disparate patterns across nutrient and mixing regimes; (iii) nuisance species may be planktonic or benthic and located outside remedial boundaries; and (iv) species differ significantly in NAM biochemistry and release. Thus, there are no robust relationships between total plankton biomass, toxins, and T&O compounds in these and other source waters. Given the potential ecological and socioeconomic threats posed by NAM outbreaks, there is a critical need to develop a multistep management framework based on more stringent restoration targets, combining broad-scale screening and nutrient management with system and taxa-specific approaches.
35
Ribeiro, Matheus S. F., Andrea Tucci, Matheus P. Matarazzo, Cristina Viana-Niero e Cristina S. F. Nordi. "Detection of Cyanotoxin-Producing Genes in a Eutrophic Reservoir (Billings Reservoir, São Paulo, Brazil)". Water 12, n. 3 (23 marzo 2020): 903. http://dx.doi.org/10.3390/w12030903.
Testo completoAbstract (sommario):
CyanoHABs (cyanobacterial harmful algal blooms) are blooms of cyanobacteria capable of producing cyanotoxins, a large group of secondary metabolites that are toxic to most eukaryotes. In this work, the main aim was to evaluate the presence of multiple genes from each of the clusters responsible for biosynthesis of cyanotoxins (cylindrospermopsin, microcystin and saxitoxin) in total DNA obtained from sixteen environmental water samples by PCR. Microcystin gene mcyE was amplified in all analyzed samples. Among the cylindrospermopsin genes analyzed, only the cyrC gene was amplified from DNA obtained from three of sixteen samples. Of the three different saxitoxin genes analyzed, sxtB and sxtI were present in four and three of the sixteen samples studied, respectively, and sxtA did not show any positive result. Based on our results, we suggest caution when using only one gene from the full clusters responsible for biosynthesis of cyanotoxins, given that it may not be sufficient to confirm or exclude the toxigenic potential of a sample.
36
Schmidt, Wido, Beate Hambsch e Heike Petzoldt. "Classification of algogenic organic matter concerning its contribution to the bacterial regrowth potential and by-products formation". Water Science and Technology 37, n. 2 (1 gennaio 1998): 91–96. http://dx.doi.org/10.2166/wst.1998.0112.
Testo completoAbstract (sommario):
The bacterial regrowth potential (BRP) and the by-products formation potential after the disinfection (DBP) are parameters recognized to be influenced by the origin of organic matter dissolved in water. A significant difference of the impact of humic compounds and algogenic organic matter (AOM), characteristic for raw waters from reservoirs, to both parameters can be assumed. In systematic laboratory experiments the influence of AOM on the BRP as well as DBP was examined. Different fractions of the AOM were chlorinated and treated with chlorine dioxide. In addition to that the influence of the ozonation was investigated. To assess the biodegradable fraction of the organic matter (BDOC) a large spectrum of by-products (aldehydes and keto-acids) was analyzed. The BRP in the water was determined by the measurement of the increase of biomass in the water samples. It could be proved, that the chlorination of intact algae cells containing waters may cause a significant increase of the biodegradability in the water if the residual chlorine is totally required. In the case of the disinfection of the AOM containing waters with chlorine dioxide the relative increase of the BRP was lower in comparison to the chlorinated waters. The preozonation of the algae containing waters indicates an additional increase of the BRP, but only by ozonation of the algae cells. The ozonation of the algae metabolites does not influence the BRP, but it causes a significant decrease of the THM-formation if chlorine is used for disinfection.
37
Лыскова (Lyskova), Надежда (Nadezhda) Сергеевна (Sergeevna), Юлия (Iuliia) Генриховна (Genrikhovna) Базарнова (Bazarnova) e Игорь (Igor') Вадимович (Vadimovic) Кручина-Богданов (Kruchina-Bogdanov ). "STUDY OF THE COMPOSITION AND PROPERTIES OF SECONDARY METABOLITES OF THE LICHEN USNEA BARBATA". chemistry of plant raw material, n. 1 (19 ottobre 2017): 121–27. http://dx.doi.org/10.14258/jcprm.2018011966.
Testo completoAbstract (sommario):
In the modern society value of many biological resources remains underestimated. Lichens are one of the unique poorly studied bioresources. These are amazing organisms, formed by symbiosis of algae and fungus. Due to this combination, lichens have a number of unique properties.In this article the results of study the composition of biologically active secondary lichen metabolites of the Usnea barbata lichen. Antioxidant activity and antimicrobial properties of dry lichen extract against bacteria Bac. Subtilis. The conditions for extraction of biologically active metabolites using solvent systems such as water, water-ethanol mixtures with ethanol content of 40 and 70%, 1,4-dioxane and a mixture of 1,4-dioxane and water (1: 1) were selected. With use of the modern analytical methods, the composition of secondary metabolites in the extracts was studied. By the method of spectroscopy in the UV and visible region of the spectrum to determine the content usnic acid, which is 16,2 (solvent - water) to 60,0 (1,4-dioxane) mg/100 ml of extract.It is shown that the dioxane extract has pronounced atioxidant properties. The active substances (in terms of usnic acid) of the dry extract of lichen Usnea barbata are able to inhibit the growth of bacteria Bac. Subtilis.
38
Subbiah, Seenivasan, Adcharee Karnjanapiboonwong, Jonathan D. Maul, Degeng Wang e Todd A. Anderson. "Monitoring cyanobacterial toxins in a large reservoir: relationships with water quality parameters". PeerJ 7 (16 luglio 2019): e7305. http://dx.doi.org/10.7717/peerj.7305.
Testo completoAbstract (sommario):
Cyanobacteria are widely distributed in fresh, brackish, and ocean water environments, as well as in soil and on moist surfaces. Changes in the population of cyanobacteria can be an important indicator of alterations in water quality. Metabolites produced by blooms of cyanobacteria can be harmful, so cell counts are frequently monitored to assess the potential risk from cyanobacterial toxins. A frequent uncertainty in these types of assessments is the lack of strong relationships between cell count numbers and algal toxin concentrations. In an effort to use ion concentrations and other water quality parameters to determine the existence of any relationships with cyanobacterial toxin concentrations, we monitored four cyanobacterial toxins and inorganic ions in monthly water samples from a large reservoir over a 2-year period. Toxin concentrations during the study period never exceeded safety limits. In addition, toxin concentrations at levels above the limit of quantitation were infrequent during the 2-year sampling period; non-detects were common. Microcystin-LA was the least frequently detected analyte (86 of 89 samples were ND), followed by the other microcystins (microcystin-RR, microcystin-LR). Cylindrospermopsin and saxitoxin were the most frequently detected analytes. Microcystin and anatoxin concentrations were inversely correlated with Cl−, SO${}_{4}^{-2}$, Na+, and NH${}_{4}^{+}$, and directly correlated with turbidity and total P. Cylindrospermopsin and saxitoxin concentrations in water samples were inversely correlated with Mg+2 and directly correlated with water temperature. Results of our study are expected to increase the understanding of potential relationships between human activities and water quality.
39
Patin, Nastassia V., Emily Brown, Gabriella Chebli, Claire Garfield, Julia Kubanek e Frank J. Stewart. "Microbial and chemical dynamics of a toxic dinoflagellate bloom". PeerJ 8 (21 luglio 2020): e9493. http://dx.doi.org/10.7717/peerj.9493.
Testo completoAbstract (sommario):
Harmful Algal Blooms (HABs) exert considerable ecological and economic damage and are becoming increasingly frequent worldwide. However, the biological factors underlying HABs remain uncertain. Relationships between algae and bacteria may contribute to bloom formation, strength, and duration. We investigated the microbial communities and metabolomes associated with a HAB of the toxic dinoflagellate Karenia brevis off the west coast of Florida in June 2018. Microbial communities and intracellular metabolite pools differed based on both bacterial lifestyle and bloom level, suggesting a complex role for blooms in reshaping microbial processes. Network analysis identified K. brevis as an ecological hub in the planktonic ecosystem, with significant connections to diverse microbial taxa. These included four flavobacteria and one sequence variant unidentified past the domain level, suggesting uncharacterized diversity in phytoplankton-associated microbial communities. Additionally, intracellular metabolomic analyses associated high K. brevis levels with higher levels of aromatic compounds and lipids. These findings reveal water column microbial and chemical characteristics with potentially important implications for understanding HAB onset and duration.
40
Ma, Xiao-yan, Ze-hua Zhang, Qing-song Li, Shi-fei Hu, Hong-yu Wang, Jun Li e Jian-meng Chen. "Simultaneous removal of algae and its odor metabolites in raw water by potassium ferrate". Desalination and Water Treatment 52, n. 1-3 (29 aprile 2013): 357–64. http://dx.doi.org/10.1080/19443994.2013.785366.
Testo completo
41
Liu, Tianji, Yitong Wang, Junguo Li, Qing Yu, Xiaoman Wang, Di Gao, Fuping Wang, Shuang Cai e Yanan Zeng. "Effects from Fe, P, Ca, Mg, Zn and Cu in Steel Slag on Growth and Metabolite Accumulation of Microalgae: A Review". Applied Sciences 11, n. 14 (17 luglio 2021): 6589. http://dx.doi.org/10.3390/app11146589.
Testo completoAbstract (sommario):
Steel slag is the solid waste produced by the steelmaking process. At present, there are differences in the treatment and utilization of this waste among countries around the world. The massive accumulation of steel slag not only occupies land, but also the heavy metal elements in steel slag leached by rainwater cause serious pollution to the soil and groundwater, both which threaten the life and survival of the surrounding residents. More and more attention has been paid to the resource utilization of slag because of the gradual promotion of energy saving and emission reduction all over the world. Currently, the fields that utilize slag focus on recycling of steel waste, acting as sinter raw material, dephosphorization of hot metal, road and water conservancy project construction, wastewater treatment material, application of CO2 capture and flue gas desulfurization or agriculture. Many researchers have carried out research and explorations on the effects of slag on microalgae’s growth and found that slag has enormous potential algal biomasses and huge advantages for promoting microalgae’s growth and the accumulation of metabolites. Under suitable conditions, slag can effectively promote microalgae’s growth and reproduction, as well as promote microalgae’s accumulation of metabolites, especially lipid accumulation. Thus, slag can be used as an ideal nutrient for microalgae. Culturing microalgae with slag can lower the cost and solve the problem of lacking Fe during the process of marine microalgae’s growth. Meanwhile, it can alleviate the phenomenon of the substantial stacking of slag. This study provides new methods for slag’s resource utilization.
42
Hu, Shi Fei, Xiao Yan Ma, Hong Yu Wang, Jun Li, Jing Huang e Yun Zhang. "Kinetics on Oxidation of Odor Contaminant-Dimethyl Trisulfide by Potassium Ferrate in Drinking Water". Advanced Materials Research 255-260 (maggio 2011): 2987–93. http://dx.doi.org/10.4028/www.scientific.net/amr.255-260.2987.
Testo completoAbstract (sommario):
Metabolites of alga that will induce disgusting odor into drinking water such as geosmin, 2-methylisoborneol and dimethyl trisulfide, etc. attracted more and more scholar’s attention recently. Dimethyl trisulfide was newly noticed to be criminal of some water supply accidents of unpleasant odor in our country and was found removed effectively by oxidation agents. Batch tests were carried out in this research to investigate reaction kinetics of dimethyl trisulfide oxidized by potassium ferrate in water. Results showed that dimethyl trisulfide can be removed by potassium ferrate and the rate of decomposition followed third-order kinetics, the third-order reaction rate constant k= 6.57×10L/ (s·mg).
43
Taki, Kazuo, Tatsuhiro Seki, Sakiyori Mononobe e Kohichi Kato. "Zeta potential measurement on the surface of blue-green algae particles for micro-bubble process". Water Science and Technology 57, n. 1 (1 gennaio 2008): 19–25. http://dx.doi.org/10.2166/wst.2008.787.
Testo completoAbstract (sommario):
Any kind of blue-green alga produces metabolites of musty substances and toxins. Therefore, it is necessary to remove the blue-green algae, and processing also including nutrient removal is desired for the water quality improvement of eutrophic lakes. The purpose of this study has been to investigate the possibility of a flotation system using a hybrid technique (chemical compounds and electrostatic bridge) applied to raw water containing phytoplankton with high pH of water, and to examine the zeta potential value of phytoplankton surface and the removal efficiency for phytoplankton, ammonia, nitrogen, and phosphoric acid. The results were as follows: firstly, zeta potential of M. aeruginosa particles was observed to achieve charge neutralization on their surface by adhesion of magnesium hydroxide precipitation with increasing pH. Secondly, maximum removal efficiency concerning chlorophyll-a was observed as 84%, and this efficiency was obtained in the condition of pH > 10, and magnesium hydroxide precipitation was observed. Thirdly, in the pH condition that the maximum removal efficiency of chlorophyll-a was obtained, the removal efficiency and the amount of decrease of NH4-N and PO4-P before and after the change of pH values were observed as 6.7% (0.04 mg-P/L) and 63.6% (0.07 mg-N/L), respectively.
44
Banks, C. J., G. B. Koloskov, A. C. Lock e S. Heaven. "A computer simulation of the oxygen balance in a cold climate winter storage WSP during the critical spring warm-up period". Water Science and Technology 48, n. 2 (1 luglio 2003): 189–96. http://dx.doi.org/10.2166/wst.2003.0118.
Testo completoAbstract (sommario):
The paper considers factors that determine the oxygen balance in extreme climate waste stabilisation ponds during the critical spring warm-up period. At this time BOD load on the pond is a maximum, due to accumulation of wastewater under the ice during the winter. The paper describes the operation of a typical cold climate WSP and the events leading to a balanced steady state system as spring develops into summer. A mathematical model to simulate conditions within a batch fed experimental pond over the transient period is described. To model temperature changes in the water body experimental data were fitted to a generalised equation based on diurnal fluctuations in air temperature. The results are plotted in a normalised form and show the diurnal fluctuation and time lapse as the depth of the pond increases. Maximum daily water temperature lags behind maximum light intensity. Bacterial growth is simulated by a Monod kinetic model in which growth rate depends on initial substrate concentration; temperature compensation is applied using a temperature activity coefficient. Oxygen utilisation is calculated from substrate removal. Algal growth rate is more complicated as it is affected by temperature and light availability. Algal oxygen production potential is considered in terms of its primary metabolite yield, which is then used in a Monod equation to estimate the growth rate. The model uses a mass balance approach to determine dissolved oxygen concentration in the pond. The model is still in a simple form but shows reasonable agreement, in terms of events and time lapses, to measured parameters in experimental ponds recovering from ice cover.
45
Goddard, Stephen, e Fatma Saif Al-Abri. "Integrated aquaculture in arid environments". Journal of Agricultural and Marine Sciences [JAMS] 23 (10 gennaio 2019): 52. http://dx.doi.org/10.24200/jams.vol23iss0pp52-57.
Testo completoAbstract (sommario):
Around one third of the globe is classified as desert or arid (<200mm rain annually) and most such regions lack food security. Traditional freshwater aquaculture is often a marginal activity and competes with agriculture for limited water resources. Developing technologies offer new opportunities to increase productivity of aquaculture through integration with vegetable production in aquaponic systems and to reduce water requirements through the application of biofloc technology. Aquaponic systems combine aquaculture and hydroponic plant production and are integrated within a re-cycled water system. Fish waste metabolites provide the nutrients for plants grown in soil-less, hydroponic systems. Biofloc farming systems operate with minimum or zero water exchange. Suspended biofloc particles develop in fish tanks under conditions of full aeration and controlled carbon to nitrogen ratios. They comprise algae, bacteria, protozoa and particulate organic matter held in a loose matrix. They provide in-situ treatment of harmful fish metabolites, are protein rich, contain essential fatty acids, vitamins and minerals and supplement the diets of filter-feeding farmed species. The integration of fish culture with vegetable production provides new opportunities for small and medium enterprises. Integrated farms occupy a small footprint, optimise the use of resources and can be built close to population centres. This paper reviews current developments in aquaponics and biofloc technology against the background of food security needs in arid regions.
46
Goddard, Stephen, e Fatma Saif Al-Abri. "Integrated aquaculture in arid environments". Journal of Agricultural and Marine Sciences [JAMS] 23, n. 1 (10 gennaio 2019): 52. http://dx.doi.org/10.24200/jams.vol23iss1pp52-57.
Testo completoAbstract (sommario):
Around one third of the globe is classified as desert or arid (<200mm rain annually) and most such regions lack food security. Traditional freshwater aquaculture is often a marginal activity and competes with agriculture for limited water resources. Developing technologies offer new opportunities to increase productivity of aquaculture through integration with vegetable production in aquaponic systems and to reduce water requirements through the application of biofloc technology. Aquaponic systems combine aquaculture and hydroponic plant production and are integrated within a re-cycled water system. Fish waste metabolites provide the nutrients for plants grown in soil-less, hydroponic systems. Biofloc farming systems operate with minimum or zero water exchange. Suspended biofloc particles develop in fish tanks under conditions of full aeration and controlled carbon to nitrogen ratios. They comprise algae, bacteria, protozoa and particulate organic matter held in a loose matrix. They provide in-situ treatment of harmful fish metabolites, are protein rich, contain essential fatty acids, vitamins and minerals and supplement the diets of filter-feeding farmed species. The integration of fish culture with vegetable production provides new opportunities for small and medium enterprises. Integrated farms occupy a small footprint, optimise the use of resources and can be built close to population centres. This paper reviews current developments in aquaponics and biofloc technology against the background of food security needs in arid regions.
47
Boronina, Liudmila, Arkadiy Sokolsky e Lev Fesenko. "Identification of organic pollutants of water in sources of water supply (on the example of the astrakhan region)". E3S Web of Conferences 135 (2019): 01013. http://dx.doi.org/10.1051/e3sconf/201913501013.
Testo completoAbstract (sommario):
In today’s diverse world, one of the most urgent tasks is environmental protection, rational use and reproduction of natural resources, conservation of biological diversity. The problem of clean water is one of the most important places in the solution of this problem because surface waters are the most sensitive natural environment link. Without careful monitoring of the state indicated by the latter, it is impossible to prevent the occurrence of adverse environmental situations, maintain the health of the nation and ensure the quality of life. Based on the results of the analysis of indicators of the quality of the water source, the required volumes of water for the consumer and the requirements of the consumer for the produced water, a decision is made on the technology for purifying the required water. Special climatic conditions (sharply continental climate, high summer temperatures, low water levels, etc.) negatively affect the quality indicators of the water source. The article presents the results of a study of surface water by microbiological indicators and phytoplankton. Water was investigated in the area of the channel-type surface water intake structure located in the Astrakhan region on the Volga. It is revealed that the river belongs to the category of dirty. Moreover, there is a positive trend in the development of this process. Applied water treatment technologies are not able to fulfill the tasks to ensure a safe drinking regime. It is known that chlorination of water during water treatment does not affect the removal of metabolites secreted by massively developing species of cyanobacteria (blue-green algae). The authors made recommendations for improving water treatment facilities.
48
Yagi, Masakazu. "Musty Odour Problems in Lake Biwa 1982-1987". Water Science and Technology 20, n. 8-9 (1 agosto 1988): 133–42. http://dx.doi.org/10.2166/wst.1988.0234.
Testo completoAbstract (sommario):
This paper discusses the results obtained by two research groups investigating the musty odour problem in Lake Biwa during the years 1967 to 1987. The study has shown that the problem is caused by the growth of three species of planktonic blue-green algae in the southern lake. These algae produce as metabolites either 2-methyl-isoborneol (MIB) or geosmin and it is these compounds which give rise to the musty odour. Recently the musty odour problem has expanded from western to eastern part in the southern lake. The occurrence of the problem has also changed from spring to early summer and more recently it has begun to appear also during the autumn months. The maximum concentrations for geosmin and MIB, 1,050 and 860 ng/l, recorded for the lake occurred in the autumn of 1985.
49
Arc, Erwann, Martina Pichrtová, Ilse Kranner e Andreas Holzinger. "Pre-akinete formation in Zygnema sp. from polar habitats is associated with metabolite re-arrangement". Journal of Experimental Botany 71, n. 11 (9 marzo 2020): 3314–22. http://dx.doi.org/10.1093/jxb/eraa123.
Testo completoAbstract (sommario):
Abstract In streptophytic green algae in the genus Zygnema, pre-akinete formation is considered a key survival strategy under extreme environmental conditions in alpine and polar regions. The transition from young, dividing cells to pre-akinetes is associated with morphological changes and the accumulation of storage products. Understanding the underlying metabolic changes could provide insights into survival strategies in polar habitats. Here, GC-MS-based metabolite profiling was used to study the metabolic signature associated with pre-akinete formation in Zygnema sp. from polar regions under laboratory conditions, induced by water and nutrient depletion, or collected in the field. Light microscopy and TEM revealed drastic changes in chloroplast morphology and ultrastructure, degradation of starch grains, and accumulation of lipid bodies in pre-akinetes. Accordingly, the metabolite profiles upon pre-akinete formation reflected a gradual shift in metabolic activity. Compared with young cells, pre-akinetes showed an overall reduction in primary metabolites such as amino acids and intermediates of the tricarboxylic acid (TCA) cycle, consistent with a lower metabolic turnover, while they accumulated lipids and oligosaccharides. Overall, the transition to the pre-akinete stage involves re-allocation of photosynthetically fixed energy into storage instead of growth, supporting survival of extreme environmental conditions.
50
Mu, Rui Min, Xue Liang Yuan e Gui Xia Ma. "Removal Characteristics of Microcystis aeruginosa with One Brevibacillus parabrevis Strain". Advanced Materials Research 113-116 (giugno 2010): 928–31. http://dx.doi.org/10.4028/www.scientific.net/amr.113-116.928.
Testo completoAbstract (sommario):
In this study, one strain of algicidal bacterium H01 was selected from the water body polluted by Microcystis aeruginosa. It had good removal effects on Microcystis aeruginosa and the removal characteristics on Microcystis aeruginosa were studied. The results indicated that the removal efficiency was connected with such factors as temperature and pH. And the experiment on algicidal mechanism indicated that it lysed the algae cells by secreting metabolites. According to the analysis of its physiological characteristics and 16S rDNA gene sequence, the strain H01 was identified as Brevibacillus parabrevis.