Formation of plastocyanin and cytochrome c-553 in different species of blue-green algae

Fifteen species from different genera of blue-green algae have been examined for their formation of plastocyanin (PC) and cytochrome c-553 (cyt c-553) in high or low Cu media. In addition to species which contain only cyt c-553 and those which completely exchange their cyt c-553 by PC, a new regulatory type was detected in which this exchange was incomplete. By comparing different species, it could be shown that either this incomplete exchange of cyt c-553 by PC as well as lack of PC in some other blue-green algae is not caused by restricted Cu uptake but is due to different biosynthetic and regulatory properties. Occurrence of PC and cyt c-553 cannot be used as a taxonomic criterium to classify blue-green algae. However, formation of either one or both of these redox components fits well into a line of evolution of the photosynthetic apparatus from the blue-green algae via green algae to higher plants.Abbreviations PC plastocyanin; cyt c-553, cytochrome c-553     

Observations of Toxic Blue-Green Algae (Cyanobacteria) in Some Scandinavian Lakes

Blooms of blue-green algae from 51 eutrophic Scandinavian lakes were investigated during the period 1978–1984, to ascertain the occurrence of toxinogenic species. Toxicity assays were performed by intraperitoneal injection of suspensions of freeze-dried algal material in mice. Toxin-producing blue-green algae were found in 30 lakes. They belonged to 11 different species of the six genera Anabaena, Aphanizomenon, Gomphosphaeria, Microcystis, Nodularia and Oscillatoria. The presence of toxinogenic strains of blue-green algae seemed quite constant in several of the localities studied. In some lakes, more than one toxic species were found to develop simultaneously. The level of toxicity showed large variation (MLD100, 6 to > 2500 mg/kg), but clinical and pathological changes were quite uniform. The results indicate that water-blooms of toxin-producing blue-green algae, in the geographical area in question, are regionally widespread. In some localities, blooms of blue-green algae are apparently always toxic. Several aspects of the toxic blue-green algae problem are discussed.     

Seasonal variation of phytoplankton community in Thale Sap Songkhla, a lagoonal lake in southern Thailand

The phytoplankton in Thale Sap Songkhla was investigated at 2–3 month intervals from August 1991 to October 1993. The abundance of phytoplankton ranged from 1.4×10⁶ to 1.3×10⁹ cells m^–3. A total of 6 divisions with 103 genera were identified as Bacillariophyta: 49 genera, Chlorophyta: 21 genera, Pyrrhophyta: 15 genera, Cyanophyta: 12 genera, Chrysophyta: 3 genera and Euglenophyta: 3 genera. Although phytoplankton abundance was distinctly greater in the first year of study (August 1991–June 1992) than in the second year (August 1992–October 1993), their patterns are similar: 2 peaks yearly. The peaks of phytoplankton occurred in the heavy rainy season (northeast monsoon) and the light rainy season (southwest monsoon). The main bloom was found during December–January, with a predominance of blue-green algae (e.g. Aphanizomenon andPhormidium) and green algae (e.g. Eudorina). Their species composition also increased, an effect of the large amount of rainfall resulting in low salinity during the northeast monsoon. The minor bloom was produced by diatoms during June–July when water salinity was moderate to seawater. Both phytoplankton numbers and species composition were high. However, unpredictably heavy rainfall during the southwest monsoon period may reduce diatom production due to rapid immediate replacement by blue-green species. Besides salinity concentration, a low total nitrogen: total phosphorus (TN: TP) ratio tended to support the growth of blue-green algae. The diversity of phytoplankton was lowest in the heavy rainy period.     

Measurement of photorespiration in algae

The rates of true and apparent photosynthesis of two unicellular green algae, one diatom and four blue-green algae were measured in buffer at pH 8.0 at subsaturating concentrations of dissolved inorganic carbon (13-27 micromolar). Initial rates of depletion from the medium of inorganic carbon and ¹⁴C activity caused by the algae in a closed system were measured by gas chromatography and by liquid scintillation counting, respectively. The rate of photorespiration was calculated as the difference between the rates of apparent and true photosynthesis. The three eucaryotic algae and two blue-green algae had photorespiratory rates of 10 to 28% that of true photosynthesis at air levels of O₂. Reduction of the O₂ level to 2% caused a 52 to 91% reduction in photorespiratory rate. Two other blue-green algae displayed low photorespiratory rates, 2.4 to 6.2% that of true photosynthesis at air levels of O₂, and reduction of the O₂ concentration had no effect on these rates.     

Amino acid sequence of Chlorogloeopsis fritschii ferredoxin: taxonomic and evolutionary aspects

The amino acid sequence of Chlorogloeopsis fritschii ferredoxin was determined for its carboxymethylated derivative by using solid-phase sequencing, fragmentation with various enzymes, and manual Edman degradation procedures. The ferredoxin was composed of 98 amino acid residues and lacked methionine and tryptophan. The sequence was as follows: Ala-Thr-Tyr-Lys-Val-Thr-Leu-Ile-Asn-Asp-Ala-Glu- Gly-Leu-Asn-Gln-Thr-Ile-Glu-Val-Asp-Asp-Asp-Thr-Tyr-Ile-Leu-Asp-Ala-Ala-Glu- Glu-Ala-Gly-Leu-Asp-Leu-Pro-Tyr-Ser-Cys-Arg-Ala-Gly-Ala-Cys-Ser-Thr-Cys-Ala-Gly-Lys-Ile-Lys-Ser-Gly-Thr-Val-Asp-Gln-Ser-Asp-Gln-Ser-Phe-Leu-Asp-Asp-Asp- Gln-Ile-Glu-Ala-Gly-Tyr-Val-Leu-Thr-Cys-Val-Ala-Tyr-Pro-Thr-Ser-Asp-Cys-Thr-Ile-Glu-Thr-His-Lys-Glu-Glu-Glu-Leu-Tyr. A phylogenetic tree was constructed on the basis of a comparison of various algal ferredoxins and it was found that C. fritschii ferredoxin was closely related to Mastigocladus laminosus ferredoxin, though they are in different genera of the blue-green algae. Aspects of the taxonomy and molecular evolution of blue-green algal ferredoxins are discussed.     

Isolation and properties of fungi that lyse blue-green algae.

Of 70 pure microbial cultures isolated from aquatic habitats, soil, and air according to the ability to lyse live blue-green algae, 62 were fungi representing the genera Acremonium, Emericellopsis, and Verticillium. Algal-lysing fungi were isolated from all habitat types sampled. The remaining isolates comprised four bacteria and four streptomycetes. All isolates lysed Anabaena flos-aquae and, in most cases, several other filamentous and unicellular blue-green algae. The fungi generally showed greater activity than most other isolates towards a wider range of susceptible algae, including green algae in some cases. Acremonium and Emericellopsis isolates, but not Verticillium, also inhibited the growth of blue-green algae and gram-positive bacteria, but did not lyse the latter. Lysis of blue green algae by Acremonium and Emericellopsis spp. was associated with the formation of diffusible heat-stable extracellular factors which, evidence suggests, could be cephalosporin antibiotic(s). Blue-green algae were also lysed by pure cephalosporin C. The frequent isolation of lytic fungi from algal habitats suggests a possible natural algal-destroying role for such fungi, which might be exploitable for algal bloom control.     

Isolation and properties of fungi that lyse blue-green algae.

Of 70 pure microbial cultures isolated from aquatic habitats, soil, and air according to the ability to lyse live blue-green algae, 62 were fungi representing the genera Acremonium, Emericellopsis, and Verticillium. Algal-lysing fungi were isolated from all habitat types sampled. The remaining isolates comprised four bacteria and four streptomycetes. All isolates lysed Anabaena flos-aquae and, in most cases, several other filamentous and unicellular blue-green algae. The fungi generally showed greater activity than most other isolates towards a wider range of susceptible algae, including green algae in some cases. Acremonium and Emericellopsis isolates, but not Verticillium, also inhibited the growth of blue-green algae and gram-positive bacteria, but did not lyse the latter. Lysis of blue green algae by Acremonium and Emericellopsis spp. was associated with the formation of diffusible heat-stable extracellular factors which, evidence suggests, could be cephalosporin antibiotic(s). Blue-green algae were also lysed by pure cephalosporin C. The frequent isolation of lytic fungi from algal habitats suggests a possible natural algal-destroying role for such fungi, which might be exploitable for algal bloom control.     

Characterization of Hemiselmis amylosa sp. nov. and phylogenetic placement of the blue-green cryptomonads H. amylosa and Falcomonas daucoides

The morphology and ultrastructure of a new freshwater blue-green cryptomonad, Hemiselmis amylosa sp. nov., is described. In addition, a marine blue-green cryptomonad isolate was confirmed as Falcomonas daucoides by electron microscopy and phycobilin analysis so that it could be included in molecular sequence studies, since the original isolate is no longer available. Complete ssu rRNA gene sequences for H. amylosa and F. daucoides were obtained. Our freshwater isolate of Hemiselmis possesses the same general features described for blue-green marine species, but it differs in having an eyespot, and multiple, single thylakoids penetrating the pyrenoid; therefore, a new blue-green, freshwater species is described. Phylogenetic analyses of H. amylosa and F. daucoides, as well as 24 other cryptophyte algae, indicate a monophyletic origin for all blue-green cryptomonads. Falcomonas forms a sister clade to blue-green cryptomonads, indicating that it is the most primitive extant blue-green cryptomonad and probably diverged early from other blue-green genera. Furthermore, we suggest that the eocyte blue-green cryptomonad may have originated from a Proteomonas-like progenitor that underwent a pigment change, resulting in a Falcomonas-like cell. Based on comparative morphology, the Proteomonas haplomorph may be a likely candidate in the evolutionary transformation from red to blue-green in cryptomonads; however, phylogenetic analyses neither support nor refute this hypothesis. Finally, the current status of cryptomonad classification is addressed.     

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.     

PHYTOPLANKTON OF THE SUSQUEHANNA RIVER NEAR BINGHAMTON,NEW YORK: SEASONAL VARIATIONS; EFFECT OF SEWAGE EFFLUENTS1,2

Net phytoplankton samples were collected weekly for 13 months at points above and below sewage effluents. Sixty-three genera and 130 taxa were identified: diatoms, 19 genera, 44 taxa; greens, 31 genera, 67 taxa; blue-greens, 6 genera, 8 taxa. Downstream from the sewage effluents the number of taxa was unchanged but the number of organisms was definitely increased. This increase was most pronounced for green and blue-green algae, and least for diatoms. The seasonal distribution of algae was that usually seen in waters of the North Temperate Zone. The particular taxa and number of taxa found were those of productive waters but not typical of heavily polluted waters.     

Changes in the abundance of blue-green algae related to nutrient loadings in the nearshore of Lake Michigan

Nutrient loadings to the nearshore of southeastern Lake Michigan have undergone a remarkable reduction. This reduction can affect the nutrient supply and result in biological changes. Changes in phytoplankton community, particularly the blue-green algae, can be related to nutrient changes. After thermal stratification, sudden increases in the blue-green algae population were significantly correlated to soluble reactive phosphorus concentrations. Phosphorus-stimulated low dissolved silica and phosphorus limitations after stratification appear to be primary factors contributing to the success of these algae.     

Effect of blue-green alga (Cyanobacteria) and their exometabolites on formation of resting forms and variability of Yersinia pseudotuberculosis

Research, carried out with the use of bacteriological methods and polymerase chain reaction, revealed that the transformation of Y. pseudotuberculosis, associated with blue-green algae Anabaena variabilis, into resting (noncultivable) forms took shorter time than in soil extract containing no algae. The exometabolites of "old" cultures of these algae sharply accelerated the formation of resting Y. pseudotuberculosis forms. The influence of the algae and the products of their metabolism was manifested far more intensively at 22 degrees C than at 4 degrees C. After passage through infusoria resting Y. pseudotuberculosis forms, preserved in the mucous covering of cyanobacteria, partially reverted into vegetative forms, capable of growing on solid culture media. The revertants essentially differed from the initial vegetative forms by having lower enzymatic activity, agglutinability and cytopathogenicity, as well as by the loss of plasmid p45. The probable role of blue-green algae, widely spread in soils and water reservoirs, in the processes of reversible transformation of Y. pseudotuberculosis vegetative and resting forms, closely connected with seasonal changes of temperature conditions.     

Nitrogen Turnover in Marine and Brackish Habitats: I. Nitrogen Fixation

Potential nitrogen-fixing genera were found to be abundant intwo natural populations of blue-green algae, one from a rockycoast and the other from a sand-dune slack. ¹⁵N studies confirmedthat these populations fixed nitrogen in the laboratory andin the field. Preliminary quantitative data on Fixation in thefield suggest that the algae contribute appreciable quantitiesof fixed nitrogen to the environments in which they occur.     

Heterotrophic Growth of Blue-Green Algae in Dim Light

A unicellular blue-green alga, Agmenellum quadruplicatum, and a filamentous blue-green alga, Lyngbya lagerheimíi, were grown heterotrophically in dim light with glucose as major source of carbon and possibly energy. The dim-light conditions did not support autotrophic growth. The two blue-green algae appeared to have the same metabolic block, namely an incomplete tricarboxylic acid cycle, as has been found in other obligately phototrophic blue-green algae. Under dim-light conditions, glucose made a greater contribution to cell constituents (amino acids) of A. quadruplicatum and L. lagerheimii than under high-light conditions.     

巨大螺旋藻光合放氧和超微结构的研究

选用常温下培养的巨大螺旋藻为材料,对其光合放氧与超微结构进行了观察和研究。结果表明：１）巨大螺旋藻具有较强的放氧能力;２）巨大螺旋藻细胞内存在有含量极丰富的类囊体,气泡,藻胆体及羧化体等特写结构与其光合放氧特性相适应;３）类囊体膜片层在细胞的部分区域已趋于重叠,且封闭成一独立系统存在,具类似真核生物叶绿体的结构;４）从进化角度来看,巨大螺旋藻类囊体膜存在的方式可以作为叶绿体系统演化的证据之一,即真     

The Utricularia-Cyanophyta association and its nitrogen-fixing capacity

Utricularia inflexa Forsk. growing in a shallow lake near Dar es Salaam, Tanzania was found to be abundantly associated with blue-green algae and other microorganisms, though blue-green algae were not found in the lake water. The epiphytes occurred both on the outer surfaces of the macrophyte and inside its traps. Seven genera of the Cyanophyta were observed, amongst which Anabaena was the most abundantly and consistently associated.Both epiphytes on the outer surfaces of the macrophyte and those inside mature traps fixed nitrogen in situ. Mature parts of the macrophyte fixed nitrogen at higher rates than immature parts, indicating the former was associated with a greater abundance of nitrogen fixers. The Utricularia-Cyanophyta association showed a nitrogen fixation (acetylene reduction) rate of 2012 nmol C₂H₄ g^–1 dry weight h^–1 or, in terms of lake area, of 4 500 nmol C₂H₄ m^–2 h^–1. The relative contributions of blue-green algae and bacteria were not determined.It is proposed that the association may involve a degree of physiological interdependence and that the association has potential as a biofertilizer for rice.Based on an M.Sc. thesis by G. M. Wagner submitted to the Department of Botany, University of Dar es Salaam, 1983.Based on an M.Sc. thesis by G. M. Wagner submitted to the Department of Botany, University of Dar es Salaam, 1983.     

Pyridine Nucleotide-Dependent Glucose Dehydrogenase Activity in Blue-Green Algae

Pyridine nucleotide-dependent glucose dehydrogenase activity (GPND) is described for the first time in cell-free extracts of certain blue-green algae. When glucose is added to these crude cell extracts, nicotinamide adenine dinucleotide phosphate is reduced at twice the rate as nicotinamide adenine dinucleotide; but evidence suggests that this activity is due to a single enzyme. The distribution and level of GPND in selected blue-green algae correlates with the heterotrophic potential of each species. In all blue-green algae where GPND was detected, O(2) uptake coupled to the GPND reaction was also observed. Both GPND and O(2) uptake apparently occur in the soluble fraction of the cell. An essential role for GPND in the heterotrophic metabolism of blue-green algae is postulated.     

FREQUENT HETEROCYST GERMINATION IN THE BLUE-GREEN ALGA GLOEOTRICHIA GHOSEI SINGH1

A unique feature, frequent heterocyst germination, has been observed in a nonsporulating mutant clone (of spontaneous origin) of the blue-green alga Gloeotrichia ghosei Singh. The controlling factor seems to be the presence of ammoniacal nitrogen in the medium. In addition, such a medium supports differentiation of successive crops of new heterocysts and their germination in the name medium and in the same algal culture. Contrary to previous observations with oilier blue-green algae, ammoniacal nitrogen does not seem to inhibit heterocyst differentiation in this alga. Both the parent alga and its mutant clone grow poorly in a nitrogen-free medium, which, although they are not completely free from bacteria, may indicate that they tire poor fixers or nonfixers. However, they form a large number of heterocysts under these conditions. The general conclusion is that the heterocysts of blue-green algae show a multiplicity of structure and function. In the present case they have reproductive function leading to direct propagation of the alga. The bearing of these findings on the interrelationships of the genera Gloeotrichia and Rivularia has been discussed. It has been concluded that the distinction between them is purely artificial.     

Algal nitrogen fixation in the tropics

Summary a)Nitrogen fixation in rice fields. Nitrogen-fixing blue-green algae grow abundantly in tropical regions and are particularly common in paddy fields. Their possible role in the nitrogen accumulation of soil has been studied. The most vigorous nitrogen-fixing blue-green algae have been assessed for use as green manure in rice fields and favorable effects have been reported in India and other countries. b)Nitrogen fixation by algae in water. The planktonic blue-green algae occur abundantly at certain time of the year in sea water and lake water, and some of them are known to be nitrogen fixers. Certain Japanese species of blue-green algae can withstand high temperatures including ten nitrogen-fixing species from hot-spring waters. c)Nitrogen fixation by symbiotic blue-green algae. Certain species of blue-green algae form associations with other organisms such as fungi, liverworts, ferns and seed plants. The relationship between these two organisms is on one occasion commensal and on others symbiotic. Certain symbiotic blue-green algae are provided with the ability to fix the atmospheric nitrogen.     

Characteristics of softwater streams in Rhode Island II. Composition and seasonal dynamics of macroalgal communities

Forty stream segments in Rhode Island, U.S.A., were examined seasonally from June 1979 to March 1982. Thirty-nine species of macroalgae were collected, respresenting 25 genera. The composition of the lotic flora was 54% green algae, 31% red algae, 5% blue-green algae, 5% xanthophytes, 3% chrysophytes and 3% diatoms. The majority of these taxa (85%) were filamentous. From a biweekly examination of five stream segments, macroalgal communities could be grouped according to light regime. Species in unshaded streams exhibited little seasonality, whereas in streams shaded by one or more layers of riparian canopy, maxima in species numbers and abundance occurred during colder seasons. The most widespread and abundant species were the blue-green alga Phormidium retzii, the green alga Draparnaldia acuta, and the diatom Eunotia pectinalis. P. retzii and E. pectinalis were aseasonal annuals, while D. acuta was primarily a winter-spring form. It appears that pH is a major factor affecting broad geographic distribution patterns of stream macroalgae, whereas the light regime established by overhanging canopy is an important factor which influences localized abundance and seasonality of lotic macroalgal communities. Niche pre-emption appears to be a common mode of resource space division among stream macroalgae in Rhode Island. E. pectinalis is the strongly developed dominant in this drainage system.