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PubMed2004

Preliminary study on the photoproduction of hydroxyl radicals in aqueous solution with Aldrich humic acid, algae and Fe(III) under high-pressure mercury lamp irradiation.

Under a high-pressure mercury lamp (HPML) and using an exposure time of 4 h, the photoproduction of hydroxyl radicals (*OH) could be induced in an aqueous solution containing humic acid (HA). Hydroxyl radicals were determined by high-performance liquid chromatography using benzene as a probe. The results showed that *OH photoproduction increased from 1.80 to 2.74 microM by increasing the HA concentration from 10 to 40 mg L(-1) at an exposure time of 4 h (pH 6.5). Hydroxyl radical photoproduction in aqueous solutions of HA containing algae was greater than that in the aqueous solutions of HA without algae. The photoproduction of *OH in the HA solution with Fe(III) was greater than that of the solution without Fe(III) at pH ranging from 4.0 to 8.0. The photoproduction of *OH in HA solution with algae with or without Fe(III) under a 250 W HPML was greater than that under a 125 W HPML. The photoproduction of *OH in irradiated samples was influenced by the pH. The results showed that HPML exposure for 4 h in the 4-8 pH range led to the highest *OH photoproduction at pH 4.0.

Benzene↗
PubMed2002

Antinociceptive activity of sulfated carbohydrates from the red algae Bryothamnion seaforthii (Turner) Kütz. and B. triquetrum (S.G. Gmel.) M. Howe.

We report the antinociceptive activity, determined by the writhing, formalin and hot-plate tests in mice, of crude (F0/60), lectin and carbohydrate fractions isolated by ammonium sulfate precipitation (0 to 60%) from Bryothamnion seaforthii and B. triquetrum, species of red algae. Not only fraction F0/60 but also lectins from both species significantly inhibited acetic acid-induced abdominal contractions after intraperitoneal or oral administrations. In the formalin test, lectins (1 and 5 mg/kg, ip, and 5 to 20 mg/kg, po) inhibited the 1st and 2nd phases (5 and 20 min, respectively), but the effect occurred predominantly on the 2nd phase. The effects of the lectins were totally or partially reversed by naloxone (2 mg/kg, sc) in the 1st and 2nd phases, respectively. Experiments performed with lectins in the absence and presence of avidin (1 mg/kg, ip) and D-mannose (1 mg/kg, ip) showed that avidin did not interfere with the effect of B. seaforthii lectin but partially reversed the effect of B. triquetrum lectin. D-Mannose completely reversed the effects of both species. F0/60 fractions from both algae significantly increased the latency time in response to thermal stimuli, and naloxone reversed antinociception, indicating the involvement of the opioid system in both the peripheral and central effects of the fractions. In the writhing test, the carbohydrate fractions were the most active, inhibiting the contractions by 71 and 79% (B. triquetrum) and by 46 and 69% (B. seaforthii) at doses of 1 and 5 mg/kg, ip, respectively. Sulfated carbohydrate fractions of B. seaforthii and B. triquetrum, containing only about 5% protein as contaminants, are probably responsible for the antinociceptive effects of these red algae.

Analgesics↗
PubMed2004

The alga Bryothamnion seaforthii contains carbohydrates with antinociceptive activity.

Bryothamnion seaforthii, a red alga common to the Northeastern coast of Brazil, was used to prepare the protein fraction F0/60 by ammonium sulfate precipitation. The chromatography of F0/60 on DEAE-Sephadel column resulted in two lectin fractions, PI and PII, which have antinociceptive properties in rodents. We determined the antinociceptive activity of the PII fraction and of a carbohydrate-containing fraction (CF) in mice. The CF was prepared from the dried algae, after digestion with 100 mM sodium acetate, pH 6.0, containing 5 mM cysteine, EDTA and 0.4% papain, at 60 masculine C. A 10% cetylpyridinium chloride was added to the filtrate, and the precipitate was dissolved with 2 M NaCl:ethanol (100:15, v/v) followed by the carbohydrate precipitation with ethanol. The final precipitate, in acetone, was dried at 25 masculine C. The PII fraction markedly inhibited acetic acid-induced abdominal writhing after ip administration (control: 27.1 +/- 2.20; PII 0.1 mg/kg: 5.5 +/- 1.85; 1 mg/kg: 1.6 +/- 0.72 writhes/20 min) and after oral administration (control: 32.0 +/- 3.32; PII 0.1 mg/kg: 13.1 +/- 2.50; 1 mg/kg: 9.4 +/- 3.96 writhes/20 min). PII was also effective against both phases of pain induced by 1% formalin (control, ip: 48.2 +/- 2.40 and 27.7 +/- 2.56 s; PII: 1 mg/kg, ip: 34.3 +/- 5.13 and 5.6 +/- 2.14 s; control, po: 44.5 +/- 3.52 and 25.6 +/- 2.39 s; PII 5 mg/kg, po: 26.5 +/- 4.67 and 15.3 +/- 3.54 s for the 1st and 2nd phases, respectively) and in the hot-plate test. The CF (ip) also displayed significant antinociceptive properties in all tests but at higher doses (1 and 5 mg/kg, ip and po). Thus, CF at the dose of 5 mg/kg significantly inhibited writhes (ip: 7.1 +/- 2.47 and po: 14.5 +/- 2.40 writhes/20 min) as well as the 1st (po: 19.6 +/- 1.74 s) and 2nd (po: 7.1 +/- 2.24 s) phases of the formalin test compared to controls ip and po. The antinociceptive effects of both the PII and CF in the formalin and hot-plate tests were prevented at least partially by pretreatment with the opioid receptor antagonist naloxone (2 mg/kg, sc). Moreover, both fractions retained antinociceptive activity in the acetic acid-induced writhing test following heating, a procedure which abolished the hemagglutinating activity of the fraction, presumably due to lectins also present. Finally, both fractions also prolonged the barbiturate-induced sleeping time. These results indicate that carbohydrate molecules present in the PII (26.8% carbohydrate) and CF (21% of the alga dried weight) obtained from B. seaforthii display pronounced antinociceptive activity which is resistant to heat denaturation and is mediated by an opioid mechanism, as indicated by naloxone inhibition.

Analgesics↗
PubMed2004

Influence of chloride on silver uptake by two green algae, Pseudokirchneriella subcapitata and Chlorella pyrenoidosa.

Silver bioavailability in the presence of chloride was estimated from short-term (< or = 60 min) uptake experiments with two green algae, Pseudokirchneriella subcapitata and Chlorella pyrenoidosa. In the first experiment, silver uptake was monitored under two concentration regimes in which total dissolved silver ([Ag]tot) and [Cl] were manipulated to maintain [Ag+] at a constant value (10 nM). Comparable uptake rates were measured for both treatments despite the dramatic changes in [Cl] and [Ag]tot. In the second experiment, ambient [Ag]tot was held constant (10 or 115 nM), but [Cl] was varied (0.005-50 mM) to explore the whole range of silver chloro-complexes. Intracellular silver varied markedly along the [Cl] gradient and exhibited a clear, positive correlation with ambient [Ag+] for both algae. We conclude that the biotic ligand model reliably describes silver bioavailability in the presence of chloride for the two test algae and that its applicability depends on the relative magnitudes of silver fluxes through the unstirred diffusion layer and across the cell membrane, with the latter being affected by the presence or absence of a Cu(I) transporter. In the presence of chloride, no evidence was found for the internalization of silver via anion transport or passive diffusion of the neutral mono-chloro-complex, AgCl0.

Biological Availability↗
PubMed2004

Mechanistic approaches for evaluating the toxicity of reactive organochlorines and epoxides in green algae.

Reactive electrophilic chemicals, such as reactive organochlorine compounds or epoxides, react specifically with a broad spectrum of nucleophilic biomolecules, including proteins and DNA. Conventional toxicity tests for algae, involving the observation of growth inhibition, i.e., the inhibition of cell multiplication, after several days, yield unreliable information for risk assessment because reactive compounds hydrolyze to different extents during the exposure period. The diversity of their modes of toxic action further complicates effect assessment and calls for methods yielding additional information on the mechanisms of toxicity. One of the primary targets of reactive chemicals in cells is the tripeptide glutathione (GSH), which is important for detoxification but can also be regarded as a toxicity sensor because changes in glutathione levels indicate stress. A vital system for algae is the photosynthetic system, which is indirectly affected by reactive chemicals. The test systems developed in this study for the assessment of reactive toxicity toward algae were therefore based not only on nonspecific toxicity indicators like growth inhibition but also on indicators for disturbance of photosynthesis (inhibition of photosystem II quantum yield) and glutathione metabolism. The application of the developed test systems on Scenedesmus vacuolatus after short-term exposure of 2 h showed that these tests can be used as fast screening tests for algal toxicity and in mode-of-action-based test batteries.

Chlorophyta↗
PubMed2003

Reversed-phase HPLC determination of chlorophyll a' and naphthoquinones in photosystem I of red algae: existence of two menaquinone-4 molecules in photosystem I of Cyanidium caldarium.

Chlorophyll (Chl) a', the C13(2)-epimer of Chl a, is one of the two Chl molecules constituting the primary electron donor (P700) of photosystem (PS) I of a thermophilic cyanobacterium Synechococcus elongatus. To examine whether PS I of other oxygenic photosynthetic organisms in general contain one Chl a' molecule in P700, the pigment composition of thylakoid membranes and PS I preparations isolated from red algae Porphyridium purpureum and Cyanidium caldarium was examined by reversed-phase HPLC with particular attention to Chl a' and phylloquinone (PhQ), the secondary electron acceptor of PS I. The two red algae contained one Chl a' molecule at the core part of PS I. In PS I of C. caldarium, two menaquinone-4 (MQ-4) molecules were detected in place of PhQ used by higher plants and cyanobacteria. The 1:2:1 stoichiometry among Chl a', PhQ (MQ-4) and P700 in PS I of the red algae indicates that one Chl a' molecule universally exists in PS I of oxygenic photosynthetic organisms, and two MQ-4 molecules are associated with PS I of C. caldarium.

Chlorophyll↗
PubMed2004

Heavy-metal pollution and its state in algae in Kakehashi river and Godani river at the foot of Ogoya mine, Ishikawa Prefecture.

Alga as Achnanthes minutissima among diatoms is a widely adaptable taxon on the state of an aquatic environment. In this study, it was found that diatom had a specific tolerance to heavy metals (Cu, Zn, Pb, and Cd etc.) in river water samples, because the diatom assemblage consisted of almost only Achnanthes minutissima in Kakehashi river and Godani river, which were polluted with waste water from Ogoya copper mine. The relationship between the concentrations of heavy metals (Cu, Zn, Pb and Cd) in river water and the attached substances (algae and silt etc.) and the relative abundances of diatom taxa were investigated in detail. The results indicated that the higher is the concentration of heavy metals in the river environment, the higher is only the relative abundances of Achnanthes minutissima. Thus, the taxon can be used as a bioindicator of heavy metal pollution. The relative rates of toxic chemical forms of copper in algae were 61 - 92% in the attached substances and 49-70% in the sediment on the river bed, respectively. Therefore, it was found that diatom as Achnanthes minutissima had a tolerance to heavy metals in river water, being able to live in such an environment. Since the water treated with calcium hydroxide from the deposition reservoir of Ogoya mine enters in Godani river, the river is polluted by heavy metals (Cu, Zn, Pb and Cd etc.). From the viewpoint of both biological and chemical analyses, Godani river is still polluted with heavy metals, because their concentrations in the river samples were very high. On the other hand, in Kakehashi river, the concentrations of heavy metals were very low and the distributions of some diatoms appeared in an unpolluted Nishimata river were observed. Therefore, Kakehashi river seems to be considerably recovered from heavy-metal pollution after closing the Ogoya mine.

Eukaryota↗
PubMed2002

Characterization and bioavailability of vitamin B12-compounds from edible algae.

Substantial amounts of vitamin B12 were found in some edible algae (green and purple lavers) and algal health food (chlorella and spirulina tablets) using the Lactobacillus delbrueckii subsp. lactis ATCC7830 microbiological assay method. Corrinoid-compounds were purified and characterized from these algae to clarify the chemical properties and bioavailability of the algal vitamin B12. True vitamin B12 is the predominate cobamide of green and purple lavers and chlorella tablets. Feeding the purple laver to vitamin B12-deficient rats significantly improved the vitamin B12 status. The results suggest that algal vitamin B12 is a bioavailable source for mammals. Pseudovitamin B12 (an inactive corrinoid) predominated in the spirulina tablets, which are not suitable for use as a vitamin B12 source, especially for vegetarians. algal health food, bioavailability, cobalamin, edible algae, vitamin B12

Animals↗
PubMed1999

Snow algae of the Sierra Nevada, Spain, and High Atlas mountains of Morocco.

Snow algae (Chlorophyta) are reported from the Sierra Nevada mountains in southern Spain and the High Atlas mountains of Morocco. Populations of the snow algae Chlamydomonas sp., coloring the snow orange-red, were collected from Pico de Veleta, Spain, while snow samples from Mt. Neltner in the High Atlas mountains, contained resting spores of an orange-green colored Chloromonas sp. Other microbes observed in snow samples include bacteria, fungi, heterotrophic euglenids, diatoms, nematodes, and heterotrophic mastigotes (flagellated protists). This is the first report of snow algae from the Sierra Nevada mountains of Spain and from the Afro-alpine environment.

Altitude↗
PubMed1979

[Immunofluorescent study of the basic chromosomal protein set of green algae and Euglena].

Using antisera to fractions H1, H2a, H3 and H4 of the calf thymus histones, a comparative immunofluorescent investigation of these proteins in the nuclei of Chlamydomonas reinhardii, Haematococcus pluvialis, Dunaliella salina and Euglena gracilis was carried out. It has been shown that according to the immunofluorescent test, the nuclei of these algae contain proteins close to fractions H2a, H3 and H4 of the calf thymus histones. H1 fraction in these algae is either absent or can be considered as a protein immunochemically non-related to H1 fraction of the calf thymus histone. For quantitative evaluation (in units of the immunological distance) of the difference between histones of the algae and of the calf thymus in situ by indirect immunofluorescence, it was suggested to use the ultimate dilutions of antisera to histones. It was shown that the ultimate dilutions were correlated with titres of antisera in the reaction of microcomplement fixation. Such an approach and the data obtained are of interest for studying into the evolution of nucleosome histones in unicellular and multicellular eukaryotes.

Animals↗
PubMedDate not supplied

[Sedimentation in the seasonal cycle of unicellular algae. Model analysis].

The efficiency of quick sedimentation (quicker then at normal condition) of unicellular algae at the end of seasonal cycle was studied in Okhotsk Sea. Model researches were based on the effect of competition of two algae populations. Analytical investigations of simplified variant of mathematical model and computing experiments showed that cell sedimentation and falling into the unfavorable (dark and cold) environment could be compensated by the increase in survival under these "negative" conditions. Vertical mixing of water has effect. Generally, mechanism of convective mixing is one of the factors that helps competing populations of unicellular algae to exist under conditions of changing environment.

Arctic Regions↗
PubMedDate not supplied

[Characteristics of in vivo isolation of free fatty acids by prokaryotic and eukaryotic algae under elevated and reduced temperature].

The paper describes the composition of extracellular free fatty acids (FFAs) and intracellular fatty acids (FAs) in the enrichment cultures of the prokaryotic alga Spirulina platensis and the eukaryotic alga Chlorella vulgaris grown at optimal, supraoptimal, and suboptimal growth temperatures. With increasing growth temperature, the degree of unsaturation of the intracellular FAs of both algae decreased, while that of the extracellular FFAs of S. platensis increased. The composition of the extracellular FFAs of C. vulgaris practically did not depend on the growth temperature.

Chlorella↗
PubMed1979

[Immunostimulating activity of the lipopolysaccharides of blue-green algae].

The whole cells of blue-gree algae and lipopolysaccharides isolated from these cells were shown to stimulate the production of macro-(mainly) and microglobulin antibodies in rabbits. The macro- and microphage indices in rabbits increased significantly after the injection of LPS isolated from blue-green algae 24--48 hours before infecting the animals with a virulent Y. pseudotuberculosis strain. Besides, the inhibiting action of this strain on the migration of phagocytes to the site of infection was abolished immediately after the injection. The use of the indirect hemagglutination test allowed to prove the absence of close antigenic interrelations between blue-green algae and the following organisms: Spirulina platensis, Microcystis aeruginosa, Phormidium africanum and P. uncinatum.

Adjuvants, Immunologic↗
PubMed2002

Influence of N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid pH buffer on the biological response of marine algae.

The N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES) is extensively used as pH buffer in culture media for testing chemicals. However, this study demonstrates that 0.01 M HEPES significantly reduces the rate of Cu, Pb, and Cd binding to Porphyra spp. and Enteromorpha spp. marine macroalgae. The HEPES also decreased the accumulation of Cu, Pb, and Cd but not Hg by these macroalgae. Both the extracellular adsorption and the intracellular uptake of the metals were influenced by HEPES to a similar extent. The HEPES also promoted the release of exudates by the algae, and these exudates form very stable complexes with Cu (and probably with other trace metal ions). The HEPES interference varied with the nature of the metal, the macroalga, and the season. The presence of 0.01 M HEPES in seawater cultures of the Emiliania huxleyi (a microalga) also interfered with E. huxleyi growth, liberation of Cu-complexing organic ligands, and Cu uptake. The HEPES, which displays surface activity, may facilitate the binding of metals to the algae for an initial exposure period. The metal taken up appears to stimulate the liberation of exudates that subsequently control the bioavailability of the metals and therefore metal uptake. Because HEPES can control the uptake of trace metals by algae and the production of organic ligands, the results obtained in cultures containing the HEPES pH buffer can be influenced by this component of the media.

Biological Availability↗
PubMed1964

Use of algae for support of the human in space.

Algae offer special advantages as photosynthetic plants which may be used to provide for the gas exchange requirements of man and for some fraction of his food requirement. Established principles of algal metabolism allow basic specifications. To meet a human oxygen demand of 600 1/day an algal exchanger would take up about 720 1/day of carbon dioxide, produce about 600 g/day of dry algae, and require a minimum of about 800 watt of visible light. Major technical disadvantage arises from need for input power as light and the low values of irradiance at which algae can maintain maximum efficiency. Design criteria require compromise between minimum volume and minimum power requirement. A basic design theory needs to be evolved and a number of technical problems need to be solved before proper evaluation of an algal system can be made.

Carbon Dioxide↗
PubMedDate not supplied

[Content of alginic acid and fucoidan in fucus algae of the Barents sea].

Seasonal changes in the content of alginic acid and fucoidan have been studied in four species of fucus algae from the Barents sea: Fucus vesiculosus, F. distichus, F. serratus, and Ascophyllum nodosum. These polysaccharides are accumulated in the biomass of the algae during summer and autumn. To ensure complete processing of fucus algae it is recommended that the raw material be harvested within this period.

Alginates↗
PubMedDate not supplied

[Evaluation of cell nitrogen and phosphorus quotas in accumulative cultures of chlorococcous algae].

A conceptual model of cell quota was proposed and the parameters were determined that characterize the quota dynamics during the development of algae. Based on the experimental and empirical-statistical procedures of analysis, the basal parameters of cell quotas of nitrogen and phosphorus were obtained for four species of chlorococcous algae. The data were also obtained on a variability of nitrogen and phosphorus quotas during the development of algae, as well as coefficients of excessive accumulation. The phosphorus quota changed within the limits of three orders of magnitude and the nitrogen quota, within the limits of one order. The highest coefficients of excessive accumulation were 52 and 1.8 for phosphorus and nitrogen, respectively.

Cells↗
PubMed2002

Toxicity of a rice field herbicide in a nitrogen fixing alga, Cylindrospermum sp.

Supplementation of paraquat into the culture medium proved to be highly toxic for a blue-green alga Cylindrospermum sp. A concentration of 15 microg/ml proved algicidal for the test alga. Various concentrations (0.5 microg/ml - 15 microg/ml) of the herbicide affected the growth and reduced chlorophyll and phycocyanin contents of the alga. In addition, it inhibited differentiation of heterocysts and akinetes. The inhibition of algal growth was found to be partially relieved on addition of 500 microg/ml of glucose.

Agriculture↗