Toxic cyanobacteria (blue-green algae) in Finnish fresh and coastal waters

A survey of the occurrence of toxic blooms of cyanobacteria in Finnish fresh and coastal waters was made during 1985 and 1986. Toxicity of the freeze-dried water bloom samples was tested by mouse-bioassay (i.p.). Forty-four per cent (83/188) of the bloom samples were found to be lethally toxic. Hepatotoxic blooms (54) were almost twice as common as neurotoxic ones (29). Anabaena was the most frequently found genus in toxic and non-toxic blooms and it was present in all neurotoxic samples. Statistical associations were found between hepatotoxicity and incidence of Microcystis aeruginosa, M. viridis, M. wesenbergii, Anabaena flos-aquae and Anabaena spiroides. Neurotoxicity was statistically associated with Anabaena lemmermannii, Anabaena flos-aquae and Gomphosphaeria naegeliana. Isolation of strains of cyanobacteria confirmed the occurrence of hepatotoxic and neurotoxic strains of Anabaena, as well as hepatotoxic strains of Microcystis and Oscillatoria species.Toxic blooms caused cattle poisonings at three different lakes during the study period. Toxic blooms also occurred in drinking water sources. Our study shows that toxic cyanobacteria are more common in Finnish lakes than would be expected on the basis of animal poisonings. The results of this study show the existence of toxic cyanobacteria in Finnish water supplies and the need for their continued study as agents of water based disease.     

Bioactive compounds produced by cyanobacteria

Cyanobacteria produce a large number of compounds with varying bioactivities. Prominent among these are toxins: hepatotoxins such as microcystins and nodularins and neurotoxins such as anatoxins and saxitoxins. Cytotoxicity to tumor cells has been demonstrated for other cyanobacterial products, including 9-deazaadenosine, dolastatin 13 and analogs. A number of compounds in cyanobacteria are inhibitors of proteases — micropeptins, cyanopeptolins, oscillapeptin, microviridin, aeruginosins- and other enzymes, while still other compounds have no recognized biological activities. In general cyclic peptides and depsipeptides are the most common structural types, but a wide variety of other types are also found: linear peptides, guanidines, phosphonates, purines and macrolides. The close similarity or identity in structures between cyanobacterial products and compounds isolated from sponges, tunicates and other marine invertebrates suggests the latter compounds may be derived from dietary or symbiotic blue-green algae.     

Studies on mixed mass cultivation of Anabaena spp. (nitrogen-fixing blue-green algae, cyanobacteria) on a large scale

Studies on mixed mass cultivation of Anabaena spp. on a large scale (5170m²) were conducted continuously for 3 years. Under the continental monsoon climate in northern subtropics (30°N, 115°E), 7–11 g dry weight m⁻² day⁻¹ of microalgal biomass on average was harvested in simple plastic greenhouses in the effective growth days during the warmer seasons. The maximum productivity was 22 g m⁻² day⁻¹ in the middle of summer. Observations on the productive properties of strains of Anabaena spp. indicated that they were different from and could compensate for each other in their productivities and adaptations to the seasonal changes. With different lining materials (PVC sheets, concrete, sand and soil) in the culture ponds, no significant variation of productivity was found, but bubbling with biogas in the middle of the day and the application of some growth regulating substances (2,4-D, NaHSO₃ and extracts of oyster mushroom spawn) was able to improve the production. The cost of microalgal biomass in this way was around 0·75–1·0 US dollar(s) per kilogram.     

Hydrogen metabolism in the facultative anoxygenic cyanobacteria (blue-green algae) Oscillatoria limnetica and Aphanothece halophytica

Two facultative anoxygenic photoautotrophic cyanobacteria, Oscillatoria limnetica and Aphanothece halophytica were found capable of CO₂ photoassimilation using molecular hydrogen as electron donor in a photosystem I driven reaction. A. halophytica was also capable of evolving hydrogen from Na-dithionite reduced methylviologen in a light independent reaction.Abbreviations DCMU 3-(3,4-dichlorophenyl)-1,1-dimethylurea - DSPD Disallcylidenepropanediamine - FCCP Carbonylcyanide p-trifluoromethoxyphenyl hydrazone - Tricine N-tris(hydroxy methyl)-methylglycine     

Phycochromes b and d: their occurrence in some phycoerythrocyanin-containing blue-green algae (cyanobacteria)

Abstract
Phycochromes b and d, two types of photoreversibly photochromic pigments previously extracted from the blue-green alga Tolypothrix distorta , which contains phycoerythrocyanin, have now been found in three Anabaena strains also containing phycoerythrocyanin. Tests for the presence of phycochromes b and d in a number of blue-green algae lacking phycoerythrocyanin have been negative. The possibility that phycochrome b-type absorbance changes are due to changes in the α-subunit of phycoerythrocyanin is discussed.     

The effect of Daphnia on filament length of blue-green algae

Water from a hypertrophic lake rich in filamentous blue-green algae was passed through a continuous-flow system of aquaria containing Daphnia magna, and a control system without Daphnia. Daphnia caused a significant decrease in the blue-green algal density, and a two-fold reduction in filament length. It is suggested that feeding activity of Daphnia may result in an increase in the availability of blue-green filaments to filter-feeding cladocerans.     

Composition of cyclic peptide toxins among strains ofMicrocystis aeruginosa (blue-green algae,cyanobacteria)

The distribution of the cyclic heptapeptide toxin, microcystin, was studied among 31 strains of Microcystis aeruginosa. Microcystins-RR, -YR and -LR were detected in fifteen strains and microcystin-LR was in two strains, but no toxin was found in fourteen strains. All three toxins were detected in all 12 strains belonging to the large cell-size group recognized by cell size and allozyme genotype. This pattern of toxin composition is compatible with that of M. viridis. The small cell-size group showed variation in the toxin composition as in the case of allozyme genotype.     

Consequences of iron deficiency on photosynthetic and respiratory electron transport in blue-green algae

Growth of Aphanocapsa in low iron media resulted in a decrease of the endogenous iron pool. Below a critical concentration photosynthetic electron transfer was specifically depressed. This was caused by a strong inhibition of the synthesis of cytochromes b-559 of PSII, cytochromes b-563, f-557, and the Rieske Fe-S center of the cytochrome complex and especially the Fe-S centers of PSI. The influence of iron limitation on respiration and chlorphyll formation was negligible.Paper presented at the FESPP meeting (Strasbourg, 1984)     

Chemistry and plant ecology of zinc-rich wastes dominated by blue-green algae

An account is given of the chemistry and vegetation of wet areas below the Elvins tailings pile in the Old Lead Belt of Missouri. Zinc in particular is present at highly elevated levels in the water (5.9–21.0 mg l^–1) and most sediments. The two most widespread plants are a blue-green alga,Plectonema gracillimum, and a moss,Dicranella sp. In wetter areas the latter exists predominantly as protonema.Plectonema and the protonema typically grow in very close association, although situations do occur where only one or the other is present. For instance, algal flocs in two permanent ponds consisted largely ofPlectonema and unicellular blue-green algae, with a few eukaryotic algae, but no protonema. Other dominants in the area areEleocharis sp.,Scirpus americanus andTypha latifolia. One seepage was studied in more detail; it showed marked changes in both chemistry and vegetation on passing from source to a site 15 m downstream. Aqueous Zn dropped from 21 to 8 mg l^–1. ThePlectonema-Dicranella protonema community predominated in the upper part, developing a laminated structure up to 3 cm thick (justifying recognition as a stromatolite). Further downstream a white crust including much hydrozincite and with a very high overall zinc content (c. 370 mg g^–1 Zn) was deposited over the green layer, making it endolithic in position, though probably not in origin. Still further downstream the green layer disappeared, leaving only a hard white crust. A discussion is included of the extent to which observed variations in the zinc content of water and sediments below the tailings pile are influenced by living and dead plants. An apparent diel cycle in aqueous zinc at some sites is of particular interest, as it was not matched by changes in Ca or Cd.     

Nitrate and nitrite as ‘in vivo’ quenchers of chlorophyll fluorescence in blue-green algae

The effect of nitrate and nitrite on long-term chlorophyll fluorescence has been studied in filamentous blue-green algae. Cells grown autotrophically with nitrate as nitrogen source show, under argon atmosphere, a high level of fluorescence. The addition of either nitrete or nitrite induces a significant fluorescence quenching, but, whereas in the case of nitrite no previous treatment is required, in the case of nitrate the cells have to be sonicated or treated with Triton X-100 in advance without destroying their cellular integrity. DCMU strongly inhibits the quenching of fluorescence caused by nitrate or nitrite. Using cells grown with ammonia, a nutritional repressor of the two enzymes of the nitrate-reducing system, the fluorescence quenching observed in either case becomes negligible. These results clearly indicate that both nitrate and nitrite can physiologically act as primary Hill reagents in photosynthesis in blue-green algae.

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Résumé L'effect du nitrate et du nitrite sur la fluorescence de la chlorophylle a été étudié chez quelques algues bleues filameneuses. Les cellules alimentées avec du nitrate montrent, sous argon, un haut niveau de fluorescence. L'addition de quantités égales de nitrate et de nitrite induit une diminution significative de la fluorescence, mais si, dans le cas du nitrite, un traitement préalable n'est pas nécessaire, dans le cas du nitrace, les cellules doivent être traitées légèrement aux ultra sons ou avec du Triton X-100, sans détruire leur intégrité cellulaire. Le DCMU inhibe sévèrement la diminution de fluorescence causée par le nitrate ou le nitrite. Dans les cellules alimentées avec l'ammoniaque, un répresseur des deux enzymes du système de réduction du nitrate, la diminution de fluorescence devient negligeable quel que soit le composé employé. Enfin, ces résultats montrent clairement que tant le nitrate que le nitrite peuvent être des réactifs primaires et physiologiques de la réaction de Hill dans la photosynthèse de nitrate en algues bleues.

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Alteration of the gastrointestinal microbiota of mice by edible blue-green algae

Aims:  To characterize the effect of edible blue-green algae (cyanobacteria) on the gastrointestinal microbiota of mice.
Methods and Results:  C57BL/6J mice were fed a diet supplemented with 0% or 5% dried Nostoc commune , Spirulina platensis or Afanizominon flos-aquae (w/w) for 4 weeks. Molecular fingerprinting of the colonic microbiota using denaturing gradient gel electrophoresis revealed that administration of N. commune induced major alterations in colonic microbiota composition, while administration of S. platensis or A. flos-aquae had a more subtle impact. Community profile analysis revealed that administration of N. commune did not reduce microbial diversity indices of the colonic microbiota. Despite its pronounced effects on the bacterial composition in the colon, total bacterial numbers in the gut of mice fed N. commune were not reduced as assessed by quantitative real-time PCR and bacteriological culture.
Conclusions:  The results presented here show that administration of blue-green algae, and especially N. commune , alters colonic microbiota composition in mice with limited effects on total bacterial numbers or microbial diversity.
Significance and Impact of the Study:  Blue-green algae are consumed in many countries as a source of nutrients and to promote health, and they are intensively studied for their pharmaceutical value. Given the importance of the gut microbiota for many host functions, the effects of blue-green algae on gut microbial ecology revealed during this study should be considered when using them as food supplements or when studying their pharmaceutical properties.     

Antifouling potential of cyanobacteria: a mini-review

Abstract

Cyanobacteria produce a variety of bioactive metabolites that may have allelochemical functions in the natural environment, such as in the prevention of fouling by colonising organisms. Chemical compounds from cyanobacteria are also of biotechnological interest, especially for clinical applications, because of their antibiotic, algicidal, cytotoxic, immunosupressive and enzyme inhibiting activities. Cyanobacterial metabolites have the potential for use in antifouling technology, since they show antibacterial, antialgal, antifungal and antimacrofouling properties which could be expoited in the prevention of biofouling on man-made substrata in the aquatic environment. Molecules with antifouling activity represent a number of types including fatty acids, lipopeptides, amides, alkaloids, terpenoids, lactones, pyrroles and steroids. The isolation of biogenic compounds and the determination of their structure may provide leads for future development of, for example, environmentally friendly antifouling paints. An advantage of exploring the efficacy of cyanobacterial products is that the organisms can be grown in mass culture, which can be manipulated to achieve optimal production of bioactive substances. Phycotoxins and related products from cyanobacteria may serve as materials for antimicro- and antimacrofouling applications. A survey of antibiotic compounds with antifouling potential revealed more than 21 different antifouling substances from 27 strains of cyanobacteria.     

Cyanobacteria and eukaryotic algae in sports turf and amenity grasslands: a review

A review is presented on the occurrence and role of cyanobacteria and eukaryotic algae in sports turf, especially golf curses, and on the problems arising when these organisms become abundant. The literature depends largely on observations in only a few countries, mainly Canada, New Zealand, U.K. and U.S.A., but problem growths are probably widespread. The genera reported to be conspicuous at times include Nostoc, Phormidium, Coccomyxa, Cosmarium, Cylindrocystis, Klebsormidium, Mesotaenium and Zygogonium. Conspicuous surface growths are probably most often related to unsatisfactory drainage or irrigation practices, but other factors such as fertilizer treatment (especially excess ammonium sulphate) have been implicated. These surface growths sometimes incorporate copious mucilaginous ‘slime’, which can be a serious hazard by causing people to slip. U.K. observations suggest that this is especially likely under acidic conditions, where Coccomyxa, Cylindrocystis and Mesotaenium are among the probable culprits. Some literature indicates that cyanobacteria are also associated with a subsurface black layer, which can cause serious problems for turf management where sandy soils are subject to unsatisfactory drainage. It seems likely, however, that cyanobacteria are largely, if not entirely, absent from the subsurface layer, but may form a dark layer at the turf surface overlying the position of the subsurface black layer. The dark surface layer is probably due largely to narrow filamentous cyanobacteria, whose growth may enhance the poor drainage and thus reinforce the conditions favouring the black subsurface layer associated with anoxic conditions. The soil algal vegetation of sports turf may also be expected to exhibit beneficial effects known to occur in soils of other types of community, such as nitrogen fixation by some cyanobacteria and the binding of particles. However, little study on such effects has been directed specifically to sports turf.     

Cyanobacterial metabolites with bioactivity against photosynthesis in cyanobacteria, algae and higher plants

Cyanobacteria produce a large number and variety of bioactive allelochemical substances, with a diverse range of biological activities and chemical structures, and with effects on many biochemical processes within cells. An increasing number of such metabolites is being found to be directed against oxygenic photosynthetic processes, which, in the microbial world, are unique to algae and cyanobacteria. Such chemicals are likely to be involved in regulating natural populations, and are potentially useful as biochemical tools, and as herbicidal or biocontrol agents. This revised version was published online in June 2006 with corrections to the Cover Date.     

Ecology of deepwater rice-fields in Bangladesh 4. Nitrogen fixation by blue-green algal communities

1. Aquatic macrophytes formed dense beds in fallow areas during the four and a half months of the flood season in all but one deepwater rice-growing location in Bangladesh; these included several types of life-form, but the fine-leaved species, Myriophyllum sp., Najas indica, Utricularia stellaris were often especially abundant. The same species grew inside deepwater rice fields, but at much lower densities. A similar contrast occurred for the algae, although deepwater rice often developed dense masses of epiphytes on aquatic roots, stems and leaf sheaths, when plants were growing in isolated, well-illuminated situations.
2. Two widespread algae, Aulosira fertilissima and Scytonema mirabile, were equally successful on soil in the period prior to the arrival of floodwaters and floating on the surface of the water during the flood season. Other species common during the flood season differed from those common on soil.
3. Most blue-green algae inside deepwater rice fields were heterocystous; the only species not so, but forming distinct colonies, was Aphanothece stagnina. However only non-heterocystous forms were found at one location in south Bangladesh (Phaltita) and a change from heterocystous to non-heterocystous forms was noted at the main research site (near Sonargaon) during late September in at least one year. The water column at the former was almost entirely anoxic, while the change at the latter occurred at a time when the water sometimes became anoxic during the night. It is suggested that differences in ability to tolerate anoxic periods may be a key factor in determining the success of the algal and vascular plant species in the different micro-habitats within these DWR-growing areas.
4. Although diatoms were quantitatively only a minor component of the algal biomass, they became more frequent later in the season when the water became microaerobic or anoxic for part of the day. Navicula confervacea was overall the most abundant species at the two main research locations.

     

Antibiotic activity of new cyanobacterial isolates from Australia and Asia against green algae and cyanobacteria

One hundred and ninety-eight cyanobacterial strains, newly isolated mainly from samples collected from diverse habitats in Australia, Indonesia, Nepal, Thailand and Vietnam, were screened from their antibiotic activity against green algal species of the genera Coelastrum, Scenedesmus and Monoraphidium. We report the discovery of ten strains of Fischerella, seven of Nostoc and three of Calothrix that produce antialgal compounds with a broad activity spectrum. Some of these bioactive cyanobacteria inhibited all three algae, whereas others inhibited only two, and some only one. In addition, the 20 active strains were tested against other selected cyanobacteria, including Anabaena doliolum which grows well both photoautotrophically in light and heterotrophically in darkness, and three toxic species, Microcytis aeruginosa, Anabaena circinalis and Nodularia spumigena, which are problems in Australia and other parts of the world. At least one Fischerella strain had bioactivity directed against photosynthetic electron transport of algal chloroplasts, whereas others had no effect on photosynthesis. In most cases the growth inhibitory effects were also tested in the presence of a proteinase. The results are discussed in the light of the possible nature of the chemical inhibition and also in relationship to competition and allelopathy in algal populations. This revised version was published online in June 2006 with corrections to the Cover Date.     

Growth interactions among blue-green (Anabaena Oscillarioides,Microcystis aeruginosa) and green (Chlorella sp.) algae

The growth interactions amongst the blue-green algal species Anabaena oscillarioides, Microcystis aeruginosa and the green alga, Chlorella sp. were studied both in mixed cultures and in filter cultures separated by a membrane filter in the two arms of an interaction U-tube. The role of nutrients especially phosphate upon the interaction has also been studied. Anabaena and Microcystis both inhibited the growth of Chlorella while Microcystis also inhibited the growth of Anabaena. The inhibitory effect of Microcystis was found to be dependent on high concentrations of the initial algal inocula and independent of the initial concentration of nutrients such as inorganic phosphate, indicating that the nature of the inhibition is probably due to the production of inhibitory extracellular products by Microcystis. On the other hand, the inhibitory effect of Anabaena on Chlorella is the consequence of nutrient competition with Anabaena competing more effectively for the available phosphate.     

Toxicity of the blue-green alga Oscillatoria agardhii to the mosquito Aedes aegypti and the shrimp Artemia salina

The cyanobacterium Oscillatoria agardhii 27, which does not produce mammalian neuro- or hepatotoxins, was highly toxic to the larval stages of the yellow fever mosquito Aedes aegypti: its 24-h LC₅₀ values against fourth-and second-instar larvae of A. aegypti were 8.7 and 6.1 g live cells/ml, respectively. The toxin was water-soluble and was partially purified but the chemical nature of the toxic compound(s) is still unknown. Aqueous solutions were also toxic to the newborn larvae of the brine shrimp, Artemia salina, used for the bioassay. The toxic activity of these solutions decreased markedly on heating to 90°C for 15 min.J. Kiviranta is with the Department of Pharmacy, P.O. Box 15, FIN-00014 University of Helsinki, Helsinki, Finland; A. Abdel-Hameed is usually with the Department of Microbiology, Faculty of Pharmacy, Cairo University, Kasr-El-Aini Street, Cairo, Egypt, but is presently with the Department of Applied Chemistry and Microbiology, P.O. Box 27, Viikki, Building B, FIN-00014 University of Helsinki, Helsinki, Finland.     

Comparison of the long-wave chlorophyll fluorescence in various green and blue-green algae and diatoms

Two types of long-wave fluorescence bands with similar band shape occur at room temperature in various algae: F_II700 and F_I715. F_II700 occurs in a limited number of algae, follows PS II transients, increases with culture age and is moderately increased by cooling to 83 K. F_I715 occurs in most algae, especially Anabaena, but much less in most diatoms and Tribonema. It does not follow PS II transients, does not increase with culture age and is much increased by cooling to 83 K.An interpretation for the characteristics of F_II700 and F_I715 is given.     

The consumption and utilization of the spiral blue-green algae Spirulina platensis in artificial diets by the silkworm, Bombyx mori

The consumption and utilization of various concentrations of the spiral blue-green algae, Spirulina platensis (Nordst.) Geitl., by the fourth-instar larvae of the silkworm, Bombyx mori L., was studied by incorporation into an artificial diet. The silkworms ingested more food on the low algal-powder diets, whereas they digested more efficiently on the high algal levels. The larvae fed on diets containing 30–40% algae had the shortest larval duration compared to those on low algal-powder diets. The freeze-dried powder of S. platensis is well utilized by B. mori larvae when added to artificial diets at levels between 15% and 30%, although the high algal content at 40% was slightly better for the efficiency of conversion of ingested diet into body substance (E.C.I.) and the cocoon production. However, analysis of the protein content in feces indicated an excess of the algal powder at 40%. Measurements of data on the food consumption and utilization in this study proposed that this spiral alga is dietetically utilizable as a protein source for rearing the silkworm in smaller quantities than on a soybean meal.

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Resúmé La consommation et l'utilisation de différentes concentrations de Spirulina platensis par les chenilles de 4ème stade de Bombyx mori, ont été étudiées par incorporation dans un aliment artificiel. Les vers à soie ont ingéré plus d'aliment avec les régimes à faible concentration en algue, tandis qu'ils ont digéré plus efficacement les régimes à haute concentration d'algue. Les chenilles alimentées sur des régimes contenant 30 à 40% d'algue ont eu un développement larvaire plus bref que celles alimentées sur des régimes à faible concentration. La poudre congelée et séchée de S. platensis incorporée aux taux de 15 à 30% dans le régime artificiel est bien utilisée par les chenilles de B. mori, quoiqu'une teneur de 40% soit légèrement meilleure pour l'efficacité de conversion de l'aliment en matière vivante (E.C.I.) et la production de cocons. Cependant, l'analyse du contenu protéique dans les excréments révélait un excès de poudre d'algue à 40%. L'analyse des données au cours de cette étude, sur la consommation et l'utilisation des aliments, montre que S. platensis est utilisable diét étiquement en plus petite quantité que la farine de soja comme source de protéines pour l'élevage du ver à soie.