Nodularia Harveyana Research Articles

Selective production of singlet oxygen for harmful cyanobacteria inactivation and cyanotoxins degradation: Efficiency and mechanisms

Knowledge about the impact of singlet oxygen (1O2) on the characteristics and inactivation of harmful cyanobacterial organic matter is limited. In this study, the feasibility of using an improved single-iron doped graphite-like phase carbon nitride catalyst (FeCN) to activate peroxymonosulfate (PMS) catalytic production of 1O2 to inactivate four harmful cyanobacteria was investigated. The inactivation efficiencies at 30 min were 92.77%, 66.84%, 91.06%, and 93.45% for Microcystis aeruginosa (M. aeruginosa), Nodularia harveyana, Oscillatoria sp., and Nostoc sp., respectively. This was associated with adjusting experimental parameters, such as the FeCN and PMS doses and initial pH, to obtain the maximum 1O2 yield. The quenching experiment results and electron paramagnetic resonance spectra showed that 1O2 generated via the non-radical pathway might play a dominant role in inactivating harmful cyanobacteria and degrading harmful algal toxins (Microcystin-LR and Nodularin). In addition, the FeCN-PMS system not only effectively destroyed the integrity of harmful cyanobacterial cells but also effectively degraded cyanobacterial toxins, thereby preventing severe secondary contamination by cell rupture. A possible removal mechanism was proposed. This reveals the potential of 1O2 to simultaneously inactivate harmful cyanobacteria and degrade harmful cyanobacterial toxins.

Fatty Acid Substitutions Modulate the Cytotoxicity of Puwainaphycins/Minutissamides Isolated from the Baltic Sea Cyanobacterium Nodularia harveyana UHCC-0300.

Puwainaphycins (PUW) and minutissamides (MIN) are structurally homologous cyclic lipopeptides that exhibit high structural variability and possess antifungal and cytotoxic activities. While only a minor variation can be found in the amino acid composition of the peptide cycle, the fatty acid (FA) moiety varies largely. The effect of FA functionalization on the bioactivity of PUW/MIN chemical variants is poorly understood. A rapid and selective liquid chromatography–mass spectrometry-based method led us to identify 13 PUW/MIN (1–13) chemical variants from the benthic cyanobacterium Nodularia harveyana strain UHCC-0300 from the Baltic Sea. Five new variants identified were designated as PUW H (1), PUW I (2), PUW J (4), PUW K (10), and PUW L (13) and varied slightly in the peptidic core composition, but a larger variation was observed in the oxo-, chloro-, and hydroxy-substitutions on the FA moiety. To address the effect of FA substitution on the cytotoxic effect, the major variants (3 and 5–11) together with four other PUW/MIN variants (14–17) previously isolated were included in the study. The data obtained showed that hydroxylation of the FA moiety abolishes the cytotoxicity or significantly reduces it when compared with the oxo-substituted C18-FA (compounds 5–8). The oxo-substitution had only a minor effect on the cytotoxicity of the compound when compared to variants bearing no substitution. The activity of PUW/MIN variants with chlorinated FA moieties varied depending on the position of the chlorine atom on the FA chain. This study also shows that variation in the amino acids distant from the FA moiety (position 4–8 of the peptide cycle) does not play an important role in determining the cytotoxicity of the compound. These findings confirmed that the lipophilicity of FA is essential to maintain the cytotoxicity of PUW/MIN lipopeptides. Further, a 63 kb puwainaphycin biosynthetic gene cluster from a draft genome of the N. harveyana strain UHCC-0300 was identified. This pathway encoded two specific lipoinitiation mechanisms as well as enzymes needed for the modification of the FA moiety. Examination on biosynthetic gene clusters and the structural variability of the produced PUW/MIN suggested different mechanisms of fatty-acyl-AMP ligase cooperation with accessory enzymes leading to a new set of PUW/MIN variants bearing differently substituted FA.

Видовий склад водоростей солоних приморських водойм Приазовського національного природного парку

The paper is devoted to the researches of species composition and taxonomic structure of algae in the saline coastal reservoirs of the Pryazov National Natural Park (PNNP). It is established that species composition of algae in the studied reservoirs under modern conditions includes 153 species. These species represented 7 divisions, 11 classes, 32 orders, 61 families, 92 genera. The highest species richness at the level of divisions showed Cyanoprokaryota (43.8% of the total number of species), Bacillariophyta (32.0%) and Chlorophyta (20.9%). These divisions include 148 species and form the basis of the species composition in the studied water bodies. The leading orders of algae in the researched reservoirs were Oscillatoriales and Synechococcales (23 and 20 species respectively). The most diversely represented families were: Oscillatoriaceae (13 species), Nostocaceae, Leptolyngbyaceae, Naviculaceae (8 each), Microcoleaceae, Bacillariaceae (7 each). The top list of the genera by this parameter: Leptolyngbya (6 species), Lyngbya, Nostoc, Phormidium, Nitzschia (5 each), Calothrix, Kamptonema, Cocconeis, Navicula (4each).The highest frequency of occurrence among the identified species had also diatoms, cyanoprokaryotes and green algae: Halamphora coffeiformis (5.26%), Lyngbya aestuarii (4.21%), Cladophora siwaschensis (3.51%), Hantzschia amphioxys (3.33%), Nodularia harveyana (2.98%).Our researches demonstrate that species composition of algae of the studied saline coastal reservoirs of PNNP is quite impoverished in comparison with the partial soil algae flora, as well as the species list of algae of the freshwater reservoirs and seas of Ukraine. Specific features of the taxonomic composition of the saline coastal reservoirs are manifested in the association of organisms of fresh, marine and terrestrial habitats.

Soil Algae of El-Farafra Oasis (The Western Desert, Egypt), and N2-fixation Efficiency of Five Heterocytous Cyanophytes

IN TOTAL 47 soil algal morphospecies were cultured and identified from the desert soils of El-Farafra Oasis, The Western Desert (Egypt). The most of them were related to Cyanophyta (34 algal taxa), followed by Chlorophyta and Xanthophyta (5 algal taxa belonging to each). Bacillariophyta represented only by 3 species. Moreover, this work enriched the Egyptian soil algal flora with 5 different algal taxa: Westiellopsis prolifica Janet, Cylindrospermum gregarium (Zakrz.), Cylindrospermum. licheniforme (Bory) Kutz., Chlorocloster caudatus Pasch. and Tetraktis aktinastroides Pasch. Furthermore, the potentialities of atmospheric N2-fixation efficiency of Calothrix elenkinii Kossinsk., Nodularia harveyana f. sphaerocarpa (Born. et Flah.) Elenk., Scytonema ocellatum Lyngb., Stratonostoc linckia (Roth) Elenk. and Westiellopsis prolifica Janet were investigated. However, C. elenkinii, W. prolifica and S. ocellatum exhibited to a large extent the highest fixation rates with mean values of 18.89, 30.52 and 33.01 μmole ml-1 h-1, respectively, followed by S. linckia (16.71 μmole ml-1 h-1) and Nodularia harveyana f. sphaerocarpa (12.01 μmole ml-1 h-1). In conclusion, Scytonema ocellatum and Westiellopsis prolifica can used as promising eco-friendly natural bio-fertilizers for the sustainable development in the desert habitats.

Phytoplankton of the Chaco-Pampean Plain

Fil: Zalocar, Yolanda. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Nordeste. Centro de Ecologia Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecologia Aplicada del Litoral; Argentina

An investigation of biodiesel production from microalgae found in Mauritian waters

The aim of this study was to assess the lipid content and the subsequent potential of different microalgae present in the Mauritian marine water to produce biodiesel. The share of micro-phytoplankton species in the water column was determined. The cyanobacterial mats and endosymbiotic dinoflagellates were characterised morphologically and genetically using RFLP. The samples were quantified gravimetrically and analysed using 1H &13C NMR spectroscopy. Total micro-phytoplankton count amounted to 6.59±1.27x105 cells L-1which was dominated by diatoms (95.2%), followed by dinoflagellates (2.9%) and cyanobacteria (1.9%). The cyanobacterial mats were identified as Leptolyngbya sp. and Nodularia harveyana, and the RFLP characterised the endosymbiotic dinoflagellates as the Symbiodinium clade C. The highest amount of lipid was recorded in the Symbiodinium clade C (38.39±6.58%). 1H and 13C NMR analyses indicated the presence of acyl glycerols. An attempt to synthesise biodiesel by alkaline trans-esterification reaction was also performed and the presence of biodiesel was detected using the Fourier Transform Infrared Spectroscopy. The Infrared analysis yielded peaks at around 1738cm-1 and 1200cm-1 characteristic of the carbonyl and ether groups respectively, indicating the presence of biodiesel.

Fatty acid composition of several wild microalgae and cyanobacteria, with a focus on eicosapentaenoic, docosahexaenoic and α-linolenic acids for eventual dietary uses

A total of 13 species of microalgae and 14 strains of cyanobacteria, collected directly in the Portuguese coast and lagoons, were characterized for their fatty acid contents, focusing on two with a market potential — i.e. eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA); and another already with alternative (yet somehow more expensive) natural sources — i.e. α-linolenic (ALA) acid. The purpose of this work was their eventual inclusion as additives in food or feed. ALA was the most abundant PUFA in Nannochloropsis sp. (0.616 ± 0.081 mg FA.L culture − 1 .d − 1 ), and EPA in Phaeodactylum tricornutum (0.148 ± 0.013 mg FA.L culture − 1 .d − 1 ); Pavlova lutheri was particularly rich in EPA (0.290 ± 0.005 mg FA.L culture − 1 .d − 1 ) and DHA (0.140 ± 0.037 mg FA.L culture − 1 .d − 1 ). Despite several previous reports on similar topics and encompassing some of our microalgal species, the wild nature of our strains accounts for the novelty of this work — in addition to the characterization of a few wild cyanobacteria. Eustigmatophyceae class was the best producer of ALA, while Prymnesiophyceae was the best for EPA and ALA. Nodularia harveyana exhibited the highest ALA level (0.611 ± 0.022 mg FA.L culture − 1 .d − 1 ) and Gloeothece sp. was highest in EPA (0.030 ± 0.004 mg FA.L culture − 1 .d − 1 ).

Comparative PCR analysis of toxic Nodularia spumigena and non-toxic Nodularia harveyana (Nostocales, Cyanobacteria) with respect to the nodularin synthetase gene cluster

A comparative PCR analysis of the nodularin synthetase gene cluster (nda) of two closely related Nodularia strains from the Baltic Sea was performed. Unlike the nodularin-producing Nodularia spumigena Huebel 1988/306, all 11 tested nda sequences were absent in the non-toxic Nodularia harveyana Huebel 1983/300. Our results suggest that the benthic N. harveyana strain lacks the entire 48-kb nodularin synthetase gene cluster. We describe new primers and the requisite experimental conditions for screening different nda sequences.

Phylogenetic classification of heterotrophic bacteria associated with filamentous marine cyanobacteria in culture

Fifty-one heterotrophic bacterial strains were isolated from the marine cyanobacterial cultures of heterocystous Nodularia harveyana strain Bo53 and non-heterocystous Oscillatoria brevis strain Bo10. Fluorescence in situ hybridisation and fingerprinting methods were used for a preliminary taxonomical classification of 44 of the 51 isolates. The strains obtained from Bo53 were mostly Alphaproteobacteria (10/24), followed by Bacteroidetes (7/24), and Gammaproteobacteria (3/24). The affiliation of the isolates originating from Bo10 was dominated by Alphaproteobacteria (8/20) and Bacteroidetes (7/20), followed by Gammaproteobacteria (3/20). The 16S rRNA genes of four selected isolates were sequenced. A red-coloured bacterium from Bo53 grouped with the alphaproteobacterial genus Porphyrobacter, while the other three strains, obtained from Bo10 , belonged to the alphaproteobacterial genera Roseobacter (pink) and Rhodobacter (colourless), and to the genus Muricauda (yellow) of Bacteroidetes. The findings indicated that the aerobic anoxygenic phototroph Porphyrobacter and its relatives only occurred in Bo10 culture, whereas members of the Roseobacter clade and the Bacteroidetes bacterium Muricauda sp. seemed to be more ubiquitous.

Benthic nitrogen fixation in the SW New Caledonia lagoon

Various types of microbial mats are widespread in the SW New Caledonia lagoon. Both heterocystous (Nodularia harveyana) and non-heterocystous (Hydrocoleum cantharidosmum, H. lyngbyaceum) cyanobacteria dominate these mats. Using the acetylene reduction technique, nitro- genase activity was observed at all sites. Heterocystous cyanobacteria fix N2 during the daytime, whereas non-heterocystous cyanobacteria fix N2 during the night. The intensity of nitrogenase activ- ity depended on the level of light energy received during daylight. An estimation of nitrogen fixation by benthic cyanobacteria (16.4 ± 5.4 mg N2 m -2 d -1 ) at 21 m depth (average depth of the lagoon) represented 19% of the nitrogen requirement for benthic primary production.

Screening of microalgae for species excreting norharmane, a manifold biologically active indole alkaloid

A screening of microalgae strains is described, with the objective to discover more species besides the known cyanobacterium Nodularia harveyana which excrete the manifold biologically active and co-mutagenic indole alkaloid norharmane (9H-pyrido(3,4-b)indole) into their environment. Seven more cyanobacterial species, Anabaena cylindrica, Anabaena inaequalis, Anabaenopsis siamensis, Chroococcus minutus, Nostoc carneum, Nostoc commune and Phormidium foveolarum, were newly discovered. The norharmane concentrations detected for cyanobacterial culture media varied in a species-dependent manner from less than 1 up to 525 microg l(-1). The risk for humans and livestock, resulting from the natural appearance of norharmane as an extracellular metabolite of various cyanobacteria, is discussed.

Antialgal Activity of Several Cyanobacterial Exometabolites

The isolation of norharmalane (3,4-dihydro-9H-pyrido(3,4-b)indole) from culture media of the cyanobacterium Nodularia harveyana is described. The minimum toxic quantities against selected cyanobacteria of this compound, of the two known cyanobacterial exometabolites 4,4′-dihydroxybiphenyl and norharmane (9H-pyrido(3,4-b)indole) and in addition of harmane (1-methyl-9H-pyrido(3,4-b)indole) were determined using a special TLC plate assay. The three β-carbolines harmane, norharmane and norharmalane were tested both as bases and as hydrochlorides. All four test compounds were found to be cytotoxic against the cyanobacterial test organisms in low quantities (0.5 to 18.0 μg). For the β-carbolines the following structure-response relationships were revealed: the double bond in position 3–4 and possibly the 1-methyl-group increased the cytotoxic effect of these indole alkaloids. Minimum toxic quantities detected for β-carboline bases were in general lower than those of equimolar amounts of the corresponding hydrochlorides. The possible applicability of both β-carbolines and biphenyls as agents in antifouling systems is discussed.

Screening of microalgal culture media for the presence of algicidal compounds and isolation and identification of two bioactive metabolites, excreted by the cyanobacteria Nostoc insulare and Nodularia harveyana

Culture medium extracts obtained from 115 culture media of 35 different microalgae species were screened for the presence of algicidal compounds, in particular for compounds which are cytotoxic to Arthrospira (Spirulina) laxissima. In agar plate diffusion tests and in a test system combining thin layer chromatography (TLC) with the use of an aqueous suspension of living A. laxissima cells as spray reagent, 14 microalgae species were found with cytotoxic activity of different intensity to A. laxissima. In a so-called TLC plate diffusion test, using A. laxissima and other microalgae as test organisms, the culture medium extracts of Nodularia harveyana and Nostoc insulare possessed the highest strength and range of algicidal activity. The algicidal compound in the culture medium extracts of Nodularia harveyana was shown to be norharmane (9H-pyrido(3,4-b)indole), a known indole alkaloid. The main algicidal compound in culture medium extracts of Nostoc insulare was identified as 4,4′-dihydroxybiphenyl. The possible applicability of both compounds as therapeutics or as useful agents for removing cyanobacterial water blooms or for developing new antifouling systems is discussed.

UV-B-induced synthesis of mycosporine-like amino acids in three strains of Nodularia (cyanobacteria)

Three filamentous and heterocystous cyanobacterial strains of Nodularia, Nodularia baltica, Nodularia harveyana and Nodularia spumigena, have been tested for the presence and induction of ultraviolet-absorbing/screening mycosporine-like amino acids (MAAs) by simulated solar radiation in combination with 395 (receiving photosynthetically active radiation (PAR) only), 320 (receiving PAR + UV-A) and 295 (receiving PAR + UV-A + UV-B) nm cut-off filters. Absorption spectroscopic analyses of the methanolic extracts of samples revealed a typical MAA peak at 334 nm in all three cyanobacteria. Specific contents of MAAs had a pronounced induction in the samples covered with 295 nm cut-off filters after 72 h of irradiation. In comparison, there was little induction of MAAs in the samples covered by 395 and 320 nm cut-off filters. High performance liquid chromatographic (HPLC) studies revealed the presence of two types of MAAs in all three cyanobacteria, which were identified as shinorine and porphyra-334, both absorbing maximally at 334 nm. The occurrence of porphyra-334 is rare in cyanobacteria. Specific content of both shinorine and porphyra-334 were induced remarkably only in the samples covered with 295 nm cut-off filters. The results indicate that in comparison to UV-A and PAR, UV-B is more effective in eliciting MAAs induction in the studied cyanobacteria.

RRNA sequences reflect the ecophysiology and define the toxic cyanobacteria of the genus Nodularia.

Nodularia, a member of the order Nostocales, is a bloom-forming filamentous cyanobacterium that possesses the ability to form toxic blooms. The toxin produced by Nodularia, nodularin, is a hepatotoxin, similar in structure to the heptapeptide toxin microcystin. Twenty-one strains of Nodularia, representing the species Nodularia spumigena, Nodularia harveyana and Nodularia sphaerocarpa, were analysed for toxin production by protein phosphatase inhibition assay and sequenced over the 16S rDNA region. Phylogenetic analysis of Nodularia 16S rDNA sequences found that Nodularia clustered into two main groups. An N. spumigena cluster was distinct from the benthic species N. harveyana and N. sphaerocarpa. There was no distinction between strains isolated from globally diverse locations. Nodularin-producing species were restricted to the single, evolutionally distinct cluster of N. spumigena. This observation has enabled the design of a specific 16S rRNA PCR for the rapid detection of nodularin-producing strains. Alignment of 16S rDNA sequences from toxic and non-toxic Nodularia with other members of the cyanobacteria allowed the design of both Nodularia generic and toxic N. spumigena-specific primers.

Toxicological analysis of the marine cyanobacterium Nodularia harveyana

Nodularia harveyana, a dinitrogen-fixing cyanobacterial isolate from the Mediteranean Sea, grown in an outdoor photobioreactor, was assayed for its bioactive compounds. The active substance(s) were lypophilic and showed strong allelopathic actvity against other axenic cyanobacteria, antibiotic activity against Gram-positive pathogenic bacteria and antifungal activity against two plant pathogens. The extracts were toxic (LC50 at 30 μL) for grazers such as a rotifer (Brachionus calyciflorus) and a crustacean (Thamnocephalus platyurus).

Marine Cyanophytes from the Western Cape, South Africa: Nostocales and Stigonematales

Marine Cyanophyceae belonging to the orders Nostocales and Stigonematales from the Western Cape in South Africa, have been studied and a total of twelve taxa are described. Eleven of them belong to the Order Nostocales (Calothrix codicola, C. contarenii, C. crustacea, C. pilosa, Calothrix sp., Kyrtuthrix maculans, Microchaete sp., Nodularia harveyana, Nostoc commune, Trichormus cf. subtropicus and Yonedaella lithophila) and one to the Stigonematales (Brachytrichia quoyi ). Two genera ( Brachytrichia and Yonedaella) and one species ( Calothrix codicola) are new records for South Africa. In addition, Microchaete sp. and Nostoc commune are for the first time recorded from a marine environment in South Africa,

Protective Strategies of Several Cyanobacteria against Solar Radiation

Summary When exposed to solar radiation in a slanting groove placed in a pond for 4 h the cyanobacteria Phormidium uncinatum (Tubingen and Baikal strains), Anabaena variabilis and Oscillatoria tenuis migrated from the water surface to lower levels in order to avoid high solar irradiance. The organisms accumulated at depths between 40 and 60 cm. Fluorescence emission spectra indicated that solar radiation caused an impairment of energy transfer from the accessory pigments to the photosynthetic reaction centers in the organisms found in the first 10 to 20 cm of the water column after 4 h of irradiation. Prolonged exposure of the organisms to artificial solar radiation from a Honle lamp induced the production of sunscreening pigments absorbing at 312 and at shorter wavelengths between 250 and 300 nm. In the marine cyanobacteria Nodularia harveyana and N. spumigena , only the production of the pigment absorbing at shorter wavelengths was observed.

Growth physiology of a marine nitrogen-fixing cyanobacterium (Nodularia harveyana) in outdoor culture

The performance ofNodularia harveyana, a N2-fixing cyanobacterium isolated from seawater, has been studied outdoors in two different culture systems: open pond (OP) and tubular photobioreactor (TPR). The productivity in both devices was influenced by areal density. The maximum yield obtained was 12.0 g (d.wt) m−2 day−1 in OP and 14.0 g (d.wt) m−2 day−1 in TPR in August, corresponding to the highest solar radiation received. In a month-long experiment with the cyanobacterium cultivated in TPR at high circulation speed, a net increase in productivity was obtained over that at low circulation speed. The influence of temperature on the productivity of the cultures grown in open ponds and tubular photobioreactors has been investigated. The higher productivity obtained in TPR compared to OP was attributed to its better controlled temperature conditions. In outdoor culture the maximum nitrogenase activity did not coincide with the maximum light intensity, but occurred in early afternoon. The amount of carbohydrate accumulated during the day probably influenced the rate of dark nitrogenase activity and its duration in the night.

Synthesis of (3R,25R)‐3,25‐dihydroxyhexacosyl α‐D‐glucopyranoside, the heterocyst glycolipid of the marine cyanobacterium Nodularia harveyana

Abstract(3R,25R)‐3,25‐Dihydroxyhexacosyl α‐D‐glucopyranoside (1a), the heterocyst glycolipid of Nodularia harveyana, was synthesized by starting from D‐glucose, (S)‐malic acid (4), 1‐octadecyne (5) and ethyl (R)‐3‐hydroxybutanoate (6). magnified image