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PubMed1999

The complete mitochondrial DNA sequences of Nephroselmis olivacea and Pedinomonas minor. Two radically different evolutionary patterns within green algae.

Green plants appear to comprise two sister lineages, Chlorophyta (classes Chlorophyceae, Ulvophyceae, Trebouxiophyceae, and Prasinophyceae) and Streptophyta (Charophyceae and Embryophyta, or land plants). To gain insight into the nature of the ancestral green plant mitochondrial genome, we have sequenced the mitochondrial DNAs (mtDNAs) of Nephroselmis olivacea and Pedinomonas minor. These two green algae are presumptive members of the Prasinophyceae. This class is thought to include descendants of the earliest diverging green algae. We find that Nephroselmis and Pedinomonas mtDNAs differ markedly in size, gene content, and gene organization. Of the green algal mtDNAs sequenced so far, that of Nephroselmis (45,223 bp) is the most ancestral (minimally diverged) and occupies the phylogenetically most basal position within the Chlorophyta. Its repertoire of 69 genes closely resembles that in the mtDNA of Prototheca wickerhamii, a later diverging trebouxiophycean green alga. Three of the Nephroselmis genes (nad10, rpl14, and rnpB) have not been identified in previously sequenced mtDNAs of green algae and land plants. In contrast, the 25,137-bp Pedinomonas mtDNA contains only 22 genes and retains few recognizably ancestral features. In several respects, including gene content and rate of sequence divergence, Pedinomonas mtDNA resembles the reduced mtDNAs of chlamydomonad algae, with which it is robustly affiliated in phylogenetic analyses. Our results confirm the existence of two radically different patterns of mitochondrial genome evolution within the green algae.

Animals↗
PubMed1981

Microplate technique for determining accumulation of metals by algae.

A microplate technique was developed to determine the conditions under which pure cultures of algae removed heavy metals from aqueous solutions. Variables investigated included algal species and strain, culture age (11 and 44 days), metal (mercury, lead, cadmium, and zinc), pH, effects of different buffer solutions, and time of exposure. Plastic, U-bottomed microtiter plates were used in conjunction with heavy metal radionuclides to determine concentration factors for metal-alga combinations. The technique developed was rapid, statistically reliable, and economical of materials and cells. Results (expressed as concentration factors) were in reasonably good agreement with literature values. All species of algae studied removed mercury from solution. Green algae proved better at accumulating cadmium than did blue-green algae. No alga studied removed zinc, perhaps because cells were maintained in the dark during the labeling period. Chlamydomonas sp. proved superior in ability to remove lead from solution.

Journal Article↗
PubMed1997

Differentiation of Shewanella putrefaciens and Shewanella alga on the basis of whole-cell protein profiles, ribotyping, phenotypic characterization, and 16S rRNA gene sequence analysis.

Seventy-six presumed Shewanella putrefaciens isolates from fish, oil drillings, and clinical specimens, the type strain of Shewanella putrefaciens (ATCC 8071), the type strain of Shewanella alga (IAM 14159), and the type strain of Shewanella hanedai (ATCC 33224) were compared by several typing methods. Numerical analysis of sodium dodecyl sulfate-polyacrylamide gel electrophoresis of whole-cell protein and ribotyping patterns showed that the strains were separated into two distinct clusters with 56% +/- 10% and 40% +/- 14% similarity for whole-cell protein profiling and ribotyping, respectively. One cluster consisted of 26 isolates with 52 to 55 mol% G + C and included 15 human isolates, mostly clinical specimens, 8 isolates from marine waters, and the type strain of S. alga. This homogeneous cluster of mesophilic, halotolerant strains was by all analyses identical to the recently defined species S. alga (U. Simidu et al., Int. J. Syst. Bacteriol, 40:331-336, 1990). Fifty-two typically psychrotolerant strains formed the other, more heterogeneous major cluster, with 43 to 47 mol% G + C. The type strain of S. putrefaciens was included in this group. The two groups were confirmed by 16S rRNA gene sequence analysis. It is concluded that the isolates must be considered two different species, S. alga and S. putrefaciens, and that most mesophilic isolates formerly identified as S. putrefaciens belong to S. alga. The ecological role and potential pathogenicity of S. alga can be evaluated only if the organism is correctly identified.

Animals↗
PubMed2005

Escherichia coli behavior in the presence of organic matter released by algae exposed to water treatment chemicals.

When exposed to oxidation, algae release dissolved organic matter with significant carbohydrate (52%) and biodegradable (55 to 74%) fractions. This study examined whether algal organic matter (AOM) added in drinking water can compromise water biological stability by supporting bacterial survival. Escherichia coli (1.3 x 10(5) cells ml(-1)) was inoculated in sterile dechlorinated tap water supplemented with various qualities of organic substrate, such as the organic matter coming from chlorinated algae, ozonated algae, and acetate (model molecule) to add 0.2 +/- 0.1 mg of biodegradable dissolved organic carbon (BDOC) liter(-1). Despite equivalent levels of BDOC, E. coli behavior depended on the source of the added organic matter. The addition of AOM from chlorinated algae led to an E. coli growth equivalent to that in nonsupplemented tap water; the addition of AOM from ozonated algae allowed a 4- to 12-fold increase in E. coli proliferation compared to nonsupplemented tap water. Under our experimental conditions, 0.1 mg of algal BDOC was sufficient to support E. coli growth, whereas the 0.7 mg of BDOC liter(-1) initially present in drinking water and an additional 0.2 mg of BDOC acetate liter(-1) were not sufficient. Better maintenance of E. coli cultivability was also observed when AOM was added; cultivability was even increased after addition of AOM from ozonated algae. AOM, likely to be present in treatment plants during algal blooms, and thus potentially in the treated water may compromise water biological stability.

Acetates↗
PubMed1980

Strategies of response to copper, cadmium, and lead by a blue-green and a green alga.

The toxic metal ions Cu2+, Cd2+, and Pb2+ inhibited growth of the green alga Ankistrodesmus braunii and the blue-green alga (Cyanobacterium) Anabaena, strain 7120. Some concentrations of Cu lysed Anabaena 7120 at early, but not late, stages of growth. The other metals inhibited growth without causing lysis. Adding the chelating agent nitrilotriacetic acid (NTA) did not reduce, and in some cases increased, metal toxicity to Anabaena 7120. This suggests that these metals do not act on this alga only in the ionic form. When Anabaena 7120 grew in a sublethal concentrations of Cu(NO3)2 (10(-5)M) most of the Cu was found outside the cell, in nonionic form. About half the Cd was found to be cell associated when these algae grew in the presence of 10(-5)M Cd(NO3)2. Ankistrodesmus braunii bound substantial amounts of both Cd and Cu when growing in their presence. At certain Cu levels, the amount bound per cell remained virtually constant during growth. In Cd, the amount bound per cell was highest at the beginning of growth and then fell. Cell-associated metals were found in both wall plus membrane and cytoplasmic fractions of A. braunii after mechanical lysis. When these algae grew over dialysis sacs containing sediment loaded with Cd or Cu, substantial amounts of these metals left the sediment and entered the algal cultures. They were found both cell associated and in the culture medium of A. braunii. In cultures of Anabaena 7120, Cd removed from the sediment was found in both cells and culture medium, but Cu was found almost entirely in the culture medium. The effects that bloom of such algae might have on the mobilization of these metals from sediments in natural waters are discussed.

Cadmium↗
PubMedDate not supplied

Algae in cytologic smears.

OBJECTIVE: To desmonstrate the presence of algae in smears and establish their significance. STUDY DESIGN: Microscopic examination of smears stained by the Papanicolaou technique. RESULTS: We found 12 different species of algae, clustered in three categories: Cyanophita (blue algae), Chrysophyta (yellow algae) and Chlorophyta (green algae). CONCLUSION: Algae in smears are infrequently observed, with few bibliographic references. Their presence is due to intrinsic or extrinsic contamination. They may be confused with other structures, such as fungi, Charcott crystals or adenocarcinoma cells.

Adenocarcinoma↗
PubMed1994

Concentration factors for Cs-137 in marine algae from Japanese coastal waters.

Concentration factors (CF: Bq.kg-1 in wet algae/Bq.kg-1 in filtered seawater) for Cs-137 in Japanese coastal algae, were investigated during 1984-1990. Cs-137/Cs(stable) atom ratios were also examined to clarify the distribution equilibrium of Cs-137 in marine algae and sea water. The CFs in marine algae were within the range of 5.4 approximately 92, and the geometric mean of CF was 28 +/- 2 (standard error) in Japanese coastal species. The CFs in edible species were within the range of 5.4 approximately 67, and the geometric mean of CF was 26 +/- 4 (standard error). The values of Cs-137/Cs atom ratios in marine algae and sea water indicated that Cs-137 reached an equilibrium state in partition between algae and sea water. Therefore, the CF value obtained in the present study can be regarded as an equilibrated value. Our results showed that the CF for Cs-137 in Japanese coastal algae were consistent with the Japanese guideline CFs, but were smaller than the recommended value by IAEA.

Cesium Radioisotopes↗
PubMedDate not supplied

C6-aldehyde formation by fatty acid hydroperoxide lyase in the brown alga Laminaria angustata.

Some marine algae can form volatile aldehydes such as n-hexanal, hexenals, and nonenals. In higher plants it is well established that these short-chain aldehydes are formed from C18 fatty acids via actions of lipoxygenase and fatty acid hydroperoxide lyase, however, the biosynthetic pathway in marine algae has not been fully established yet. A brown alga, Laminaria angustata, forms relatively higher amounts of C6- and C9-aldehydes. When linoleic acid was added to a homogenate prepared from the fronds of this algae, formation of n-hexanal was observed. When glutathione peroxidase was added to the reaction mixture concomitant with glutathione, the formation of n-hexanal from linoleic acid was inhibited, and oxygenated fatty acids accumulated. By chemical analyses one of the major oxygenated fatty acids was shown to be (S)-13-hydroxy-(Z, E)-9, 11-octadecadienoic acid. Therefore, it is assumed that n-hexanal is formed from linoleic acid via a sequential action of lipoxygenase and fatty acid hydroperoxide lyase (HPL), by an almost similar pathway as the counterpart found in higher plants HPL partially purified from the fronds has a rather strict substrate specificity, and only 13-hydroperoxide of linoleic acid, and 15-hydroperoxide of arachidonic acid are the essentially suitable substrates for the enzyme. By surveying various species of marine algae including Phaeophyta, Rhodophyta and Chlorophyta it was shown that almost all the marine algae have HPL activity. Thus, a wide distribution of the enzyme is expected.

Aldehyde-Lyases↗
PubMed2000

Study on the physiology and degradation of dye with immobilized algae.

Immobilization of chlorella (pyrenoidosa) with calcium alginate was carried out. Both algal growth and physiological activity increased after immobilization. Algal size and initial density have little influence on cell growth and physiological activity. Algal cell division inside the support was restricted without bubbling air containing 2% CO2. Individual algal cell increased and algal distribution inside the support was not homogeneous, indicating that within the support the resistance of mass transfer of CO2 was the limiting factor for the growth and cell division of immobilized algae. After bubbling 2% CO2, algal growth, the cell division considerably increased and individual cell size restored normally. Study of the degradation of dye (direct brown NM) by immobilized algae was better than that of free algae. Bubbling air containing 2% CO2 in the culture solution was more favorable for increasing decolorization rate. Preliminary study of co-immobilization of algae plus bacterium illustrated that the addition of bacterium increased the anabolic activity of algae, thus increased the decolorization capacity if immobilized algae for dye.

Alginates↗
PubMed2001

[The efficiency of algae removal from drinking water by ferrate].

This paper studied the efficiency of algae removal by ferrate from two kinds of raw water which were collected from Donghu and Tiegang reservoir respectively. The experimental results showed that the removal efficiency of algae reached about 95% only through PAC coagulation when the raw water was extracted from Donghu reservoir in which most of algae was Chlorella. But dealing with Tiegang raw water in which the majority of algae were Oscillatoria, terrate was used as pre-oxidant coupling with PAC coagulation not only using PAC to flocculate and the efficiency of algae removal could be up to 97.85%. However this treatment method using ferrate as pre-oxidant overmatched the traditional method prechlorination for algae removal.

Eukaryota↗
PubMed2000

[Species composition and distribution of algae in semi-desert algal crusts].

Twenty-two species of algae, including 10 Cyanophyta, 4 Chlorophyta, 6 Bacillariophyta and 2 Euglenophyta, were isolated and identified from the semi-desert algal crusts in Shapotou, Ningxia Autonomous Region. The relationship between algae and soil matrix was studied by grinding and superprobe, and the distribution of algal species in eight layers of crusts was examined under light and scanning electron microscopes. It was found that the algae exhibited a layer-typed distribution in intermicron, and the layers of algal crust from surface to inner were in order of inorganic mineral protection layer(ca. 0.02 mm), alga-enriched layer(0.02-2.5 mm) and sparse algae layer(2.5-5.0 mm). The filaments of algae were united with clay mineral by the polysaccharides and protein of their sheath, or extended directly into mineral granules to network and band sand and soil particles.

Climate↗
PubMed2000

[Studies on algae and microcystin pollution in source water of Yellow River in Zhengzhou city].

OBJECTIVE: To study the law of development of pollution with algae and microcystin (MC) in source water of Yellow River in Zhengzhou city. METHODS: Algae and MC were detected continuously for source water samples collected from B and S Water Works of Zhengzhou in 1998. Microcystin was determined with high-sensitive ELISA. RESULTS: Monthly average density of algae was 1,439 x 10(4)/L in source water of B Water Works of Zhengzhou, with peak algae density of 4,762 x 10(4)/L in August, and that of S Water Works was 1,071 x 10(4)/L. Blue-algae of higher toxicity has become dominant species in source water from S water Works. Detection rate of microcystin was 70.83% in 24 samples collected from the two water works. CONCLUSION: According to Carlson's trophic state index (TSI), as well as other indices, such as total nitrogen, total phosphorus, chemical oxygen demands (COD) and algae density in water, source water in Zhengzhou has presented characteristics of eutrophication.

Bacterial Toxins↗
PubMedDate not supplied

[Relationship between photosynthetic activity and assimilation of organic matter in marine plankton mixotrophic algae--the possibility of different metabolic strategies].

The relationship between photosynthetic and heterotrophic activities of plankton mixotrophic algae is characterized by the type of metabolic strategy. Algae with a primary photoautotrophic strategy grow at the expense of photosynthesis without uptake of organic substrates when inorganic and organic nutrients are available. They assimilate only organic substrates when inorganic nutrients are in shortage, while heterotrophic activity supports photosynthesis under conditions of inorganic nutrients deficiency. Algae with a primary heterotrophic strategy grow heterotrophicaly under repletion of inorganic and organic nutrients. Photosynthesis occurs only when organic substrates are depleted. The most mixotrophic algae combine the features of a primary photoautotrophic and a primary heterotrophic strategies. The varieties of metabolic types of mixotrophic algae form a continuum with a primary photoautotrophic strategy on the one end and a primary heterotrophic strategy on the other. The natural conditions allowing mixotrophic algae to use one or other metabolic strategy are determined by the dynamic of inorganic and organic nutrients.

Animals↗
PubMed2002

Characterization of an algae-lytic substance secreted by Bacillus cereus, an indigenous bacterial isolate from Lake Kasumigaura.

In order to develop a practical biological strategy for water bloom-control in Lake Kasumigaura, indigenous algae-lytic bacteria targeting Microcystis spp. (the dominant cyanobacteria), was first carried out. Some basic lytic characteristics of the isolates concerning the biological and physico-chemical factors in actual water environments were then investigated. Fifteen algae-lytic bacteria were successfully isolated using the double layer method. The isolate showing the highest lytic activity was identified as Bacillus cereus based on the 16SrRNA sequence. Extracellular products of B. cereus were found to be responsible for algae-lytic activity. Algae-lytic assay tests using bacterial supernatants pre-treated under several conditions indicated that the majority of the effective algae-lytic substances were either hydrophilis or hydrophobics with a carbon number less than 18, and with molecular weight less than 2000 Da. The algae-lytic activity of the bacterial supernatant was found to be enhanced under alkaline conditions, but it was lost under acidic conditions. This pH specific characteristic is advantageous for application in water bloom environments where the pH is usually in the alkaline region.

Bacillus cereus↗
PubMed2005

[Photoreduction of Se (VI) by marine algae-transitional metals-light system].

Seven marine phytoplankton, including five green algae (Tetraselmis levis, Chlorella autotrophica, Dunaliella salina, Nannochloropsis sp. and Tetraselmis subcordiformis), one diatom (Phaeodactylum tricornutum), one red alga (Porphyridium purpureum), and three usual transitional metals (Fe(III), Cu(II), Mn(II)) were used to make up marine phytoplankton-light or transitional metals-light or marine phytoplankton-transitional metals-light system. In such system, Se(VI) could be transformed into Se(IV) by photoreduction. The species transformation of selenium could be photo-induced by redox reaction of transitional metals. The photochemical activity of marine phytoplankton was confirmed for the first time, because marine phytoplankton could adsorb and concentrated of selenium, transitional metals and organic substances (including the exudation of algae, as reducing agent) which redox potentials were changed. The ratios of Se(VI) to Se(IV) were dominated by the species, the concentration of marine phytoplankton and transitional metals, and it could be enhanced through increasing the concentration of marine algae or the combined effect from marine algae and transitional metals. After photoreduction by ternary system, the ratio of Se(VI) to Se(IV) ranges from 1.17 to 2.85, which is close to the actual value in euphotic layer of seawater. The photochemical process that is induced by marine algae and transitional metals dominative the leading effects on the distribution of oxidation states of selenium.

Chlorophyta↗
PubMed2006

[Effects of nitrogen source and aeration mode on algae growth in freshwater].

Aquarium microcosms were used to study the effects of nitrogen source and aeration mode on the growth and species changes of algae in freshwater. Nitrate nitrogen(NO3(-) -N) and ammonia nitrogen(NH4(+) -N) were used as nitrogen sources. For each nitrogen source, four modes of aeration were selected, including control, continuous aeration, aeration during the day, and aeration at night. In the early stage of the experiment, algae in the NH4(+) -N treatment experiment grew well. In the later stage, algae in the NO3(-) -N treatment experiment grew better. For different aeration modes, continuous aeration show varied effects on algae growth in the two nitrogen source treatments. Day-only aeration had little effect on algae growth. Night-only aeration inhibited algae growth considerably. In NH(+) -N treatments, cyanophyta became dominant species easily. In contrast, chlorophyta dominated in NO3(-) -N treatments.

Ammonia↗
PubMedDate not supplied

[Competition of two marine diatom algae for urea and nitrate nitrogen under three levels of irradiance].

Biomass dynamics of the plankton diatoms Thalassiosira weissflogii and Pseudo-nitzschia delicatissima were analyzed in batch mono- and mixed cultures grown on media with urea or nitrate as the sources of nitrogen, under irradiance 13, 38, and 115 microE/(m(2) x s). At the initial enrichment, nitrogen concentration was 0.18 mmol, and the nitrogen : phosphorus ratio was 5 : 1. The mechanisms of competition for the limiting resource satisfactorily described the interactions between the algae grown on urea. Competitive ability of algae was characterised according to the value of competitive eddect (CE), which was calculated as the ratio of growth rate and accumulated biomass decrease in mixed culture to that in monoculture CE of algae grown on urea increased with the increasing of irradiance and was lower than that of algae grown on nitrate. CE of P. delicatissima was higher than that T. weissflogii, independently of the source of nigrogen and the level of irradiance. At 38 and 115 microE/(m(2) x s) the growth of T. weissflogii ceased earlier than that of P. delicatissima, independently of the source o nitrogen. At 13 microE/(m(2) x s) the growth of P. delicatissima ceased earlier than of T. weissflogii in on cultures grown urea, but the growth of T. weissflogii was the first to cease on nitrate. The competition revealed in experimental communities for the nitrogen of urea between plankton algae gives reasons to suggest that in natural communities plankton algae also compere under inorganic nitrogen deficiency and organic nitrogen abundance.

Culture Media↗
PubMed1979

Colchicine, nocodazole and trifluralin: different effects of microtubule polymerization inhibitors on the uptake and migration of endosymbiotic algae in Hydra viridis.

Hydra viridis (= Chlorohydra viridissima) the freshwater coelenterate, is symbiotic. Each individual animal harbours Chlorella sp. in its endodermal cells. The symbiosis may be disestablished, the partners grown independently, and then re-established experimentally. The most effective method to produce alga-free hydra was developed by Pardy (1976). In this study algae from homogenized H. viridis, English (= European) strain, were either used directly or first grown in pure culture and then injected to re-establish the symbiosis. The uptake of algae grown in culture was compared with that of algae released directly from fresh hydra. Fewer cultured algae were taken up. Four strains were tested: English, Carolina, Frome, and Jubilee. Each takes up a characteristic number of Chlorella when injected in excess. Colchicine, nocodazole and trifluralin, were tested for their effects on either uptake or migration. Colchicine had no effect. Nocodazole and trifluralin reduced both the number of algae taken up and the rate at which they were transported to the distal region of the hydra digestive cell. The effects of these drugs tended to be proportional to the concentration between 10(-8) and 10(-5) M.

Animals↗