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1.
The common green fresh water algae Chlorella vulgaris was exposed to starting concentrations of 10 μg/L selenium in the form of selenate, selenite, or selenocyanate (SeCN(-)) for nine days in 10% Bold's basal medium. Uptake of selenate was more pronounced than that of selenite, and there was very little uptake of selenocyanate. Upon uptake of selenate, significant quantities of selenite and selenocyanate were produced by the algae and released back into the growth medium; no selenocyanate was released after selenite uptake. Release of the reduced metabolites after selenate exposure appeared to coincide with increasing esterase activity in solution, indicating that cell death (lysis) was the primary emission pathway. This is the first observation of biotic formation of selenocyanate and its release into waters from a nonindustrial source. The potential environmental implications of this laboratory observation are discussed with respect to the fate of selenium in impacted aquatic systems, the ecotoxicology of selenium bioaccumulation, and the interpretation of environmental selenium speciation data generated, using methods incapable of positively identifying reduced inorganic selenium species, such as selenocyanate.  相似文献   

2.
Uptake kinetics of monomethylmercury chloride (MeHgCl) were measured for two species of green algae (Selenastrum capricomutum and Cosmarium botrytis), one blue-green algae (Schizothrix calcicola), and one diatom (Thalassiosira weissflogii), algal species that are commonly found in natural surface waters. Species differences were found with the two green algae giving the highest uptake rates, and one of them (Cosmarium) showing differences between cultures having widely different cell age (exponential versus stationary), where increases in uptake rate for cells 30 days old were about 25 times greater than cells only 3 days old when weights of cells were considered. Both Schizothrix and Thalassiosira exhibited nearly the same lower uptake rates, approximately 20 times lower than the two green algal species. Experiments with photosystem inhibitors, uncouplers, gamma-radiation, light deprivation, and extended range uptake all point to an active transport mechanism for MeHgCl.  相似文献   

3.
Species of red, brown and green seaweeds and blue-green algae were evaluated as sources of choline. A third of the seaweeds and all the blue-green algae gave very low values. Of the remainder, the brown seaweeds yielded contents between 0.1 to 6, the red 1 to 6 and the green 3 to 8 mg choline/g of dry alga. The seasonal variation was investigated in three brown algae. Commercial seaweed meals from Ascophyllum nodosum showed nearly constant levels of choline. The chromatographic behaviour of the choline-reineckate complex was also studied.  相似文献   

4.
In this work, 13 selenium species in flue gas desulfurization (FGD) waters from coal-fired power plants were separated and quantified using anion-exchange chromatography coupled to inductively coupled plasma mass spectrometry. For the first time, we identified both selenosulfate (SeSO(3)(2-)) and selenocyanate (SeCN(-)) in such waters, using retention time matching and confirmation by electrospray mass spectrometry. Besides selenite and selenate, selenosulfate was the most frequently occurring selenium species. It occurred in most samples and constituted a major fraction (up to 63%) of the total selenium concentration in waters obtained from plants employing inhibited oxidation scrubbers. Selenocyanate occurred in about half of the tested samples, but was only a minor species (up to 6% of the total selenium concentration). Nine additional Se-containing compounds were found in FGD waters, but they remain unidentified at this point.  相似文献   

5.
Short-term (< 60 min) internalization fluxes (J(int)) by the green alga Chlamydomonas reinhardtii were measured in the presence of a variety of ligands forming hydrophilic (citric, diglycolic, or nitrilotriacetic acids), amphiphilic (Suwannee River fulvic and humic acids), and hydrophobic (oxine, diethyldithiocarbamate) Ni complexes. Free nickel concentrations, ranging from 10(-10) to 10(-3) M, were evaluated by thermodynamic modeling and by a resin exchange technique. Ni internalization appeared to occur via a single transport site that was characterized by a conditional stability constant (pH 6.0, I = 10(-2) M) of 10(5.1) M(-1). In the presence of humic substances, Ni uptake could be quantitatively predicted on the basis of Ni2+ concentrations for two algae: C. reinhardtii and Chlorella kesslerii. In the presence of the hydrophobic ligands, an increase in permeability was observed due to the formation of neutral, lipophilic complexes.  相似文献   

6.
在改良克氏 (Pringsheim’s)液无机盐组分中 ,添加适量的土壤提取液、微量元素、抗生素等 ,通过比较小球藻、栅藻等藻类的生长情况和实际样品的测试 ,研制出藻类 2 # 培养基。采用液体大样法或琼脂平板法 ,2 5~ 2 8℃光照静置培养 5~ 10d ,可对饮用矿泉水、纯净水生产中污染的藻类进行定性或定量检测  相似文献   

7.
采用L18(37)正交法优化小球藻C95和小球藻C97的生长培养基,经15 L规模培养并收获小球藻;碱性乙醇法萃取游离脂肪酸,再经脲素包埋提取多不饱和脂肪酸,并用气相色谱检测二十碳五烯酸(eicosapentaenoic acid,EPA)的含量。研究结果表明:小球藻C95最优培养基(微量元素母液0.8 m L/L,维生素母液2.4 mL/L,NaH2PO4·2H2O6.0 g/L,Na2SiO3·9H2O 9.0 g/L,NaNO360.0 g/L,FeC6H5O7·5H2O 3.0 g/L);小球藻C97最优培养基(微量元素母液1.6 m L/L,维生素母液2.4 m L/L,NaH2PO4·2H2O 4.0 g/L,Na2SiO3·9H2O 11.0 g/L,NaNO380.0 g/L,FeC6H5O7·5H2O 3.0 g/L);小球藻C95和小球藻C97对数末期(分别是第4天和第5天)达到的细胞密度分别为9.53×10^7个/mL和8.91×10^7个/mL,EPA含量分别占总脂肪酸的30.2%和29.5%,小球藻C95的EPA含量要高于小球藻C97。  相似文献   

8.
21 species of common Norwegian lichens were investigated for their content of choline, ergosterol and tocopherols. The choline content varied 20-fold between species, but most lichens were good sources of choline. Law but significant concentrations of ergosterol were found in many of the samples, indicating the value of these plants as a reserve of vitamin D. a-Tocopherol was the only member of the vitamin E group detected in the lichens. The contents were higher than those found in blue-green algae, the phycobionts of many lichens. A new technique for the determination of ergosterol, based on chromatography on alumina-containing paper, was developed.  相似文献   

9.
Over the past years the importance of food additives and the development of so-called novel food increased permanently. Especially, the application of dietary supplements was on the rise. Then, more and more new products based on plants hitherto not used for human consumption were launched. Algae products containing valuable amounts of essential nutrients such as amino acids and trace elements play a decisive role. On the other hand, some algae including the blue-green algae (cyanobacteria) are capable of synthesizing harmful substances depending on species and provenience. Therefore, methods must be available to evaluate possible risks caused by toxins in algae-based dietary supplements. There are different groups of toxins related to marine algae and cyanobacteria. However, both marine algae and cyanobacteria are able to produce Paralytic Shellfish Poisoning (PSP) toxins which are potential neurotoxins. Hence, analytical methods for PSP determination have to be developed. The method for PSP toxin determination described below is based on ion-pair chromatography of the underivatized PSP toxins followed by post-column oxidation and fluorescence detection (FD). The determination of very low amounts of PSP toxins in different matrices of novel food is possible. In addition, the method allows to compare PSP profiles of various algae-based dietary supplements.  相似文献   

10.
The present study examines the role of humic acid, as a representative of dissolved organic matter, in Cd(II), Cu(II), and Pb(II) speciation and biouptake by green microalgae. Cellular and intracellular metal fractions were compared in the presence of citric and humic acids. The results demonstrated that Cd and Cu uptake in the presence of 10 mg L(-1) humic acid was consistent with that predicted from measured free metal concentrations, while Pb biouptake was higher. By comparing Cd, Cu, and Pb cellular concentrations in the absence and presence of humic acid, it was found that the influence of the increased negative algal surface charge, resulting from humic acid adsorption, on cellular metal was negligible. Moreover, the experimental results for all three metals were in good agreement with the ternary complex hypothesis. Given that metal has much higher affinity with algal sites than humic acid adsorbed to algae, the contribution of the ternary complex to metal bioavailability was negligible in the case of Cd (II) and Cu (II). In contrast, the ternary complex contributed to over 90% of total cellular metal for Pb(II), due to the comparable affinity of Pb to algal sites in comparison with humic acid adsorbed to algae. Therefore, the extension of the biotic ligand model by including the formation of the ternary complex between the metal, humic acid, and algal surface would help to avoid underestimation of Pb biouptake in the presence of humic substances by green algae Chlorella kesslerii.  相似文献   

11.
Mass developments of cyanobacteria ("blue-green algae") in lakes and brackish waters have repeatedly led to serious concerns due to their frequent association with toxins. Among these are the widespread hepatotoxins microcystin (MC) and nodularin (NOD). Here, we give an overview about the ecostrategies of the diverse toxin-producing species and about the genes and enzymes that are involved in the biosynthesis of the cyclic peptides. We further summarize current knowledge about toxicological mechanisms of MC and NOD, including protein phosphatase inhibition, oxidative stress and their tumor-promoting capabilities. One biotransformation pathway for MC is described. Mechanisms of cyanobacterial neurotoxins (anatoxin-a, homanatoxin-a, and anatoxin-a(s)) are briefly explained. We highlight selected cases of human fatalities related to the toxins. A special focus is given to evident cases of contamination of food supplements with cyanobacterial toxins, and to the necessary precautions.  相似文献   

12.
普通小球藻和蛋白核小球藻作为新食品资源,是国际上广泛研究、养殖、应用的2种小球藻属绿藻,富含蛋白质、维生素等营养物质,可提纯或转化出大量的生物活性化合物,在食品等产业具有广泛的应用潜力。该文基于近10年来普通小球藻和蛋白核小球藻在育种、养殖、收获、下游处理、食品研发方面的国外报道,就小球藻营养成分与功效、食品领域应用及存在问题、传统和新兴微藻细胞破碎技术、产业发展策略与趋势4个方面进行综述,重点介绍国内小球藻产业不破壁藻粉消化性差的现状及工业化细胞破碎技术的优缺点,基于微藻生物精炼的理念提出了小球藻产业发展的近、中、远期发展策略,以期为国内高校院所的研发及小球藻养殖加工企业的技术信息提供参考。  相似文献   

13.
Abstract: Marine algae are a promising source of beneficial compounds for human use. Among these, pro‐vitamin A carotenoids and vitamins B, C, and E stand out. The objective of this study was to investigate seasonal variation of α‐tocopherol levels in 5 species of green marine algae of the Caulerpa genus. This research was carried out with both fresh and dry specimens; and, in addition, differences arising as a result of the drying process were examined. Analyses were carried out by high‐performance liquid chromatography (HPLC) using an isocratic system and a reversed‐phase C‐18 column. The distribution of α‐tocopherol throughout the year in Caulerpa genus was variable. All samples of both fresh and dried algae contained α‐tocopherol, except for the dried C. racemosa from March 2006. The drying process was responsible for losses of α‐tocopherol ranging from 21% to 93%.  相似文献   

14.
富油微藻是制备生物燃料和提取高附加值不饱和脂肪酸的理想原料。为筛选具有高产油潜能的微藻,开发经济高效的微藻油脂提取工艺和检测方法,本文对7种富油微藻进行超临界CO2提取,并结合三氟化硼-甲醇衍生化、GC-MS分析了各微藻提取物中的35种脂肪酸组成和含量。结果表明,添加乙醇夹带剂后,各藻类的油脂收率由54.60 % ~ 82.16 %提高至75.61 % ~ 104.46 %。微藻中共检出18种脂肪酸,C16 ~ C18系列脂肪酸含量均在55.97 %以上,其中小球藻、三角褐指藻和青岛大扁藻的单不饱和脂肪酸含量分别为36.25 %、31.81 %和26.85 %,是生物柴油理想的替代品。牟氏角毛藻的不饱和脂肪酸UFAs含量达到91.15 %,可作为绿色医疗保健品的重要来源。  相似文献   

15.
Compared to the well-characterized health threats associated with contamination of fish and shellfish by algal toxins in marine fisheries, the toxicological relevance of the bioaccumulation of toxins from cyanobacteria (blue-green algae), as the primary toxigenic algae in freshwater systems, remains relatively unknown. Lake Catemaco (Veracruz, Mexico) is a small, tropical lake system specifically characterized by a year-round dominance of the known toxigenic cyanobacterial genus, Cylindrospermopsis, and by low, but detectable, levels of both a cyanobacterial hepatotoxin, cylindrospermopsin (CYN), and paralytic shellfish toxins (PSTs). In the present study, we evaluated, using enzyme-linked immunoassay (ELISA), levels of both toxins in several species of finfish caught and consumed locally in the region to investigate the bioaccumulation of, and possible health threats associated with, these toxins as potential foodborne contaminants. ELISA detected levels of both CYN and PSTs in fish tissues from the lake. Levels were generally low (≤ 1 ng g(-1) tissue); however, calculated bioaccumulation factors (BAFs) indicate that toxin levels exceed the rather low levels in the water column and, consequently, indicated bioaccumulation (BAF >1). A reasonable correlation was observed between measured bioaccumulation of CYN and PSTs, possibly indicating a mutual source of both toxins, and most likely cells of Cylindrospermopsis, the dominant cyanobacteria in the lake, and a known producer of both metabolites. The potential roles of trophic transport in the system, as well as possible implications for human health with regards to bioaccumulation, are discussed.  相似文献   

16.
Compared to the well-characterized health threats associated with contamination of fish and shellfish by algal toxins in marine fisheries, the toxicological relevance of the bioaccumulation of toxins from cyanobacteria (blue-green algae), as the primary toxigenic algae in freshwater systems, remains relatively unknown. Lake Catemaco (Veracruz, Mexico) is a small, tropical lake system specifically characterized by a year-round dominance of the known toxigenic cyanobacterial genus, Cylindrospermopsis, and by low, but detectable, levels of both a cyanobacterial hepatotoxin, cylindrospermopsin (CYN), and paralytic shellfish toxins (PSTs). In the present study, we evaluated, using enzyme-linked immunoassay (ELISA), levels of both toxins in several species of finfish caught and consumed locally in the region to investigate the bioaccumulation of, and possible health threats associated with, these toxins as potential foodborne contaminants. ELISA detected levels of both CYN and PSTs in fish tissues from the lake. Levels were generally low (≤1?ng?g?1 tissue); however, calculated bioaccumulation factors (BAFs) indicate that toxin levels exceed the rather low levels in the water column and, consequently, indicated bioaccumulation (BAF>1). A reasonable correlation was observed between measured bioaccumulation of CYN and PSTs, possibly indicating a mutual source of both toxins, and most likely cells of Cylindrospermopsis, the dominant cyanobacteria in the lake, and a known producer of both metabolites. The potential roles of trophic transport in the system, as well as possible implications for human health with regards to bioaccumulation, are discussed.  相似文献   

17.
Analysis of trace elements in seaweed   总被引:2,自引:0,他引:2  
The following trace elements have been analysed in various algae samples: arsenic, copper, molybdenum, manganese, zinc, cobalt, antimony, selenium and iron. The ash content has also been determined. The samples were collected from two different localities in Norway, one (Trondheimsfjord) characterised by a relatively strong influence of river water, industrial waste etc.; the other (Reine in Lofoten) is free from this type of contamination. In the case of two species, Ascophyllum nodosum and Laminaria hyperborea, the variation in the content of trace elements has been studied during a one-year period, samples being taken every second month. Considerable differences in the content of trace elements was found between the Laminariaceae and Fucaceae.  相似文献   

18.
We investigated whether an earlier-developed bioavailability model for predicting copper toxicity to growth rate of the freshwater alga Pseudokirchneriella subcapitata could be extrapolated to other species and toxicological effects (endpoints). Hardness and dissolved organic carbon did not significantly affect the toxicity of the free Cu2+ ion to P. subcapitata (earlier study) and Chlorella vulgaris(this study), but a higher pH resulted in an increased toxicity for both species. Regression analysis showed significant linear relationships between ECxpCu (= "effect concentration" that produces x% adverse effect, expressed as pCu = -log of the Cu2+ activity) and pH. By linking these regression models with a geochemical metal speciation model, dissolved copper concentrations that elicit a given adverse effect (EC(X)dissolved) can be predicted. Within the pH range investigated (5.5-8.7), slopes of the linear EC(X)pCu vs pH regression models varied between 1.301 and 1.472 depending on the species and the effect level (10% or 50%) considered. In a statistical sense these slopes were all significantly different from one another (p < 0.05), suggesting that this empirical regression model does not yet capture the full complexity of toxicological copper bioavailability to algae. However, we demonstrated that regression models with an "average" slope of 1.354 had predictive power very similar to those of regression models with species and effect-specific slopes. Additionally, the "average" regression model was further successfully validated for other species (Chlamydomonas reinhardtii and Scenedesmus quadricauda) and for different toxicological effects/endpoints (growth rate, biomass yield, and phosphorus uptake rate). For all these toxicity datasets effect concentrations of copper could be predicted with this "average" model by errors of less than a factor of 2 in 94-100% of the cases. The success of this "average" model suggests the possibility that the pH-based linear regression model may form a sound conceptual basis for modeling the toxicological bioavailability of copper to green algae in regulatory assessments, although a full mechanistic understanding is lacking and should be the focus of future studies.  相似文献   

19.
海藻是海洋中未开发完全的生物新资源,富含各种有利用价值的活性代谢产物。为了确定海藻中次级代谢产物的丰富度,该实验利用化学筛选方法(薄层层析色谱(TLC)、高效液相色谱(HPLC)、气相色谱-质谱(GC-MS))对江篱、刺麒麟菜、异枝麒麟菜、石花菜及小球藻这五株海藻中的次级代谢产物进行初步筛选。结果表明,通过薄层层析色谱和高效液相色谱分析得出江蓠和石花菜显色明显,代谢产物丰富且易于提取分离。通过气相色谱-质谱分析色谱分析得出,石花菜、小球藻的石油醚相成分复杂,未知化合物较多,特别是石花菜和小球藻可以进行重点研究,为后续海藻活性代谢产物研究与应用上的研发提供有力的实验基础。  相似文献   

20.
In this study we evaluate the potential of anaerobic granular sludge as an inoculum for the bioremediation of selenium-contaminated waters using species-specific analytical methods. Solid species formed by microbial reduction were investigated using X-ray absorption near-edge structure (XANES) spectroscopy at the selenium K-edge. Furthermore, dissolved selenium species were specifically determined by ion chromatography (IC) and solid-phase microextraction gas chromatography-mass spectrometry (SPME-GC-MS). Least-squares linear combination of the XANES spectra for samples incubated with the highest selenate/selenite concentrations (10(-3) M) show the predominance of elemental selenium and a Se(-I) selenide, such as ferroselite, the thermodynamically most stable iron selenide. In contrast, elemental selenium and Se(-II) selenides are the main species detected at the lower selenate/selenite concentrations. In each repeated fed batch incubation, most aqueous selenite anions were converted into solid selenium species, regardless of the type of electron donor used (acetate or H(2)/CO(2)) and the selenium concentration applied. On the other hand, at higher concentrations of selenate (10(-4) and 10(-3) M), significant amounts of the oxyanion remained unconverted after consecutive incubations. SPME-GC-MS demonstrated selenium alkylation with both electron donors investigated, as dimethyl selenide (DMSe) and dimethyl diselenide (DMDSe). Selenite was even more alkylated in the presence of H(2)/CO(2) (maximum 2156 μg of Se/L of DMSe + DMDSe) as compared to acetate (maximum 50 μg of Se/L). In contrast, selenate was less alkylated using both electron donors (maximum 166 and 3 μg of Se/L, respectively). The high alkylation potential for selenite limits its bioremediation in selenium laden waters involving H(2)/CO(2) as the electron donor despite the fact that nontoxic elemental selenium and thermodynamically stable metal selenide species are formed.  相似文献   

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