Browsing by Subject "syanobakteerit"

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  • Rissanen, Johanna (Suomen ympäristökeskus, 1999)
    Ympäristöopas 63
    Lämpimänä heinäkuun päivänä tekisi mieli mennä uimaan, mutta uimapaikan vesi näyttää vihertävältä. Onko vedessä sinilevää ja uskallanko mennä uimaan? Mistä tunnistan sinilevän? Voiko sinilevähaittoja vähentää? Näihin ja moniin muihin levän ja levähaittoihin liittyviin kysymyksiin löytyy vastaus tästä oppaasta. Oppaassa esitellään värikuvin erilaisia leviä ja niiden aiheuttamia ilmiöitä. Siinä vastataan usein esitettyihin levän, levähaittoihin ja levien myrkyllisyyteen liittyvän kysymyksiin. Oppaassa neuvotaan mitä voi tehdä, kun sinilevää on runsaasti. Lisäksi kerrotaan, mitä kukin voi tehdä leväongelmien vähentämiseksi. Teos on tarkoitettu niin lomailijoille, mökkiläisille, ranta-asukkaille kuin myös ympäristöalan ja kuntien työntekijöille.
  • Humisto, Anu (Helsingin yliopisto, 2014)
    Syanobakteerit tuottavat bioaktiivisia sekundääri- eli erikoismetabolian tuotteita. Syanobakteerien bioaktiivisia yhdisteitä on rakenteiltaan lukuisia erilaisia ja ne voidaan jakaa pääryhmiin peptidit, polyketidit, alkaloidit ja lipopolysakkaridit. Yhdisteistä on löydetty muun muassa antibakteerisia, antifungaalisia ja antiviraalisia ominaisuuksia. Lisäksi näihin bioaktiivisiin aineisiin kuuluu terveysriskin aiheuttavia toksisia yhdisteitä. Planktiset syanobakteerit ovat saaneet runsaasti huomiota niiden muodostamien massaesiintymien vuoksi, mutta myös benttiset eli sedimentissä tai erilaisilla pinnoilla elävät syanobakteerit voivat aiheuttaa terveysriskin. Benttisillä syanobakteereilla on myös potentiaalia uusien bioaktiivisten yhdisteiden löytymisessä biotekniikan tai lääketeollisuuden tarkoituksiin. Tutkimuksessa seulottiin Itämeren ja järven benttisten syanobakteerien tuottamia bioaktiivisia yhdisteitä. Syanobakteerikannat tunnistettiin 16S rRNA geenin avulla ja niiden bioaktiivisuutta tarkasteltiin maljadiffuusiomenetelmän avulla, PCR:n avulla etsittiin tunnettuja biosynteesigeenejä. Bioaktiivisia yhdisteitä pyrittiin tunnistamaan LC/MS-menetelmällä. Tunnistetut syanobakteerit muodostivat monipuolisen benttisille syanobakteereille tyypillisen lajikirjon, jossa bioaktiivisia ominaisuuksia havaittiin 24 % tutkituista kannoista. Bioaktiivisia ominaisuuksia löydettiin niin meri- kuin järviympäristöistä eristetyiltä kannoilta. Useita bioaktiivisuuksia esiintyi muun muassa Nostoc- ja Anabaena-syanobakteereilla. Benttiset syanobakteerit tuottivat antifungaalisia yhdisteitä, kuten hassallidiinia ja skytofysiiniä sekä sytotoksista anabaenolysiiniä. Lisäksi löydettiin useita syanobaktiinien biosynteesigeenejä. Benttisiltä syanobakteereilta ei havaittu mikrokystiinin tai anatoksiini-a:n biosynteesigeenejä. Antimikrobisia ominaisuuksia löydettiin kahdesta syanobakteerikannasta, joiden tuottamia bioaktiivisia yhdisteitä ei vielä tunnistettu. Benttiset syanobakteerit tuottavat siis useita tunnettuja bioaktiivisia yhdisteitä ja ovat myös potentiaalinen uusien bioaktiivisten yhdisteiden lähde.
  • Heinilä, Lassi Matti Petteri (Helsingin yliopisto, 2017)
    Cyanobacteria, also referred as blue-green algae, are abundant everywhere on earth inhabi-ting terrestrial and marine environments and living in symbiosis with several other organisms. Cyanobacteria were the first oxygenic photosynthetic organisms on earth and many species are also capable of fixing atmospheric nitrogen which makes them important primary produ-cers in many ecosystems. Cyanobacteria are nevertheless best known for producing toxic compounds. Cyanobacteria produce a variety of bioactive compounds including toxic ones. Some of these compounds have a potential as drugs. Most of these compounds are produ-ced by nonribosomal peptide synthetases and polyketide synthases. Nostoc sp. CENA543 is a cyanobacteria isolated from Brazilian wetland Pantanal. The strain was found to produce hepatptoxic nodularin, bioactive anabaenopeptins and a pre-viously unkown peptide. In this work the chemical structure and the biosynthetic gene cluster of the unkown peptide were characterized. Amount of produced nodularin was measured and biosynthetic genes of nodularin and anabaenopeptins were examined. Also the optimal growth conditions for the strain were studied. Essential methods applied in this work were liquid cromatography and mass spectromet-ry. To examine the biosynthetic genes DNA extraction methods and bioinformatic tools such as AntiSMASH, BLAST, Artemis and BioEdit were applied. The growth conditions were in-vestigated on different growth media. Bioactivity of the compounds were examined on disc diffusion assays and with the Kawabata method for enzyme activity. The results of this study show that Nostoc sp. CENA543 produces toxic amounts of no-dularin. The novel peptide group was named pseudospumigins. Six variants of pseudospu-migins were observed, the main variant being pseudospumigin A. Amino acid sequence of pseudospumigin A is Hpla-D-Hty-L-Ile-Argininal with mass of 612,4 Da. Gene clusters of nodularin and anabaenopeptin match corresponding genes of Nodularia spuimigena CCY9414. The biosynthetic genes of pseudospumigin have high resemblance to spumigin genecluster of Nodularia spuimigena CCY9414. Change in adenylation domain substrate specificity and deletion of three additional genes would axplain the difference between pseu-dospumigins and spumigins.
  • Salmi, Pauliina; Mäki, Anita; Mikkonen, Anu; Pupponen, Veli-Mikko; Vuorio, Kristiina; Tiirola, Marja (Suomen ympäristökeskus, 2021)
    Boreal Environment Research 26: 17-27
    The smaller the phytoplankton, the greater effort is required to distinguish individual cells by optics-based methods. Flow cytometry is widely applied in marine picophytoplankton research, but in freshwater research its role has remained minor. We compared epifluorescence microscopy and flow cytometry in assessing the composition, abundance and cell sizes of autofluorescent picophytoplankton in epilimnia of 46 Finnish lakes. Phycocyaninrich picocyanobacteria were the most dominant. The two methods yielded comparable total picophytoplankton abundances, but the determination of cell sizes, and thus total biomasses, were on average an order of magnitude higher in the microscopy results. However, flow cytometry yielded higher cell sizes when applied on small-celled cultured algae. Our study demonstrated that both epifluorescence microscopy and flow cytometry are useful methods in assessing abundances of phycocyanin-rich and phycoerythrin-rich picocyanobacteria and eukaryotic picophytoplankton in lakes. However, accurate determination of cell size and biomass remain challenges for microscopy and especially for flow cytometry.
  • Wood, Steffaney M.; Kremp, Anke; Savela, Henna; Akter, Sultana; Vartti, Vesa-Pekka; Saarni, Saija; Suikkanen, Sanna (Frontiers in Microbiology, 2021)
    Frontiers in Microbiology 12
    Cyanobacteria of the order Nostocales, including Baltic Sea bloom-forming taxa Nodularia spumigena, Aphanizomenon flosaquae, and Dolichospermum spp., produce resting stages, known as akinetes, under unfavorable conditions. These akinetes can persist in the sediment and germinate if favorable conditions return, simultaneously representing past blooms and possibly contributing to future bloom formation. The present study characterized cyanobacterial akinete survival, germination, and potential cyanotoxin production in brackish water sediment archives from coastal and open Gulf of Finland in order to understand recent bloom expansion, akinete persistence, and cyanobacteria life cycles in the northern Baltic Sea. Results showed that cyanobacterial akinetes can persist in and germinate from Northern Baltic Sea sediment up to >40 and >400 years old, at coastal and open-sea locations, respectively. Akinete abundance and viability decreased with age and depth of vertical sediment layers. The detection of potential microcystin and nodularin production from akinetes was minimal and restricted to the surface sediment layers. Phylogenetic analysis of culturable cyanobacteria from the coastal sediment core indicated that most strains likely belonged to the benthic genus Anabaena. Potentially planktonic species of Dolichospermum could only be revived from the near-surface layers of the sediment, corresponding to an estimated age of 1–3 years. Results of germination experiments supported the notion that akinetes do not play an equally significant role in the life cycles of all bloom-forming cyanobacteria in the Baltic Sea. Overall, there was minimal congruence between akinete abundance, cyanotoxin concentration, and the presence of cyanotoxin biosynthetic genes in either sediment core. Further research is recommended to accurately detect and quantify akinetes and cyanotoxin genes from brackish water sediment samples in order to further describe species-specific benthic archives of cyanobacteria.
  • Lahti, Kirsti (Finnish Environment Institute, 1997)
    Monographs of the Boreal Environment Research 4
  • Suikkanen, Sanna; Uusitalo, Laura; Lehtinen, Sirpa; Lehtiniemi, Maiju; Kauppila, Pirkko; Mäkinen, Katja; Kuosa, Harri (Elsevier, 2021)
    Food Webs 28, e00202
    Blooms of cyanobacteria are recurrent phenomena in coastal estuaries. Their maximum abundance coincides with the productive period of zooplankton and pelagic fish. Experimental studies indicate that diazotrophic, i.e. dinitrogen (N2)-fixing cyanobacterial (taxonomic order Nostocales) blooms affect zooplankton, as well as other phytoplankton. We used multidecadal monitoring data from one archipelago station (1992–2013) and ten open sea stations (1979–2013) in the Baltic Sea to explore the potential bottom-up connections between diazotrophic and non-diazotrophic cyanobacteria and phyto- and zooplankton in natural plankton communities. Random forest regression, combined with linear regression analysis showed that the biomass of cyanobacteria (both diazotrophic and non-diazotrophic) was barely connected to any of the phytoplankton and zooplankton variables examined. Instead, physico-chemical variables (salinity, temperature, total phosphorus), as well as spatial and temporal variability seemed to have more significant connections to both phytoplankton and zooplankton variables. Zooplankton variables were also connected to the biomass of phytoplankton groups other than cyanobacteria (such as chrysophytes, cryptophytes and prymnesiophytes), and phytoplankton variables had connections with the biomass of different zooplankton groups, especially copepods. Overall, negative relationships between cyanobacteria and other plankton taxa were scarcer than expected based on previous experimental studies.
  • Kraft, Kaisa; Seppälä, Jukka; Hällfors, Heidi; Suikkanen, Sanna; Ylöstalo, Pasi; Anglès, Sílvia; Kielosto, Sami; Kuosa, Harri; Laakso, Lauri; Honkanen, Martti; Lehtinen, Sirpa; Oja, Johanna; Tamminen, Timo (Frontiers Media S.A., 2021)
    Frontiers in Marine Science 8: 594144
    Cyanobacteria are an important part of phytoplankton communities, however, they are also known for forming massive blooms with potentially deleterious effects on recreational use, human and animal health, and ecosystem functioning. Emerging high-frequency imaging flow cytometry applications, such as Imaging FlowCytobot (IFCB), are crucial in furthering our understanding of the factors driving bloom dynamics, since these applications provide community composition information at frequencies impossible to attain using conventional monitoring methods. However, the proof of applicability of automated imaging applications for studying dynamics of filamentous cyanobacteria is still scarce. In this study we present the first results of IFCB applied to a Baltic Sea cyanobacterial bloom community using a continuous flow-through setup. Our main aim was to demonstrate the pros and cons of the IFCB in identifying filamentous cyanobacterial taxa and in estimating their biomass. Selected environmental parameters (water temperature, wind speed and salinity) were included, in order to demonstrate the dynamics of the system the cyanobacteria occur in and the possibilities for analyzing high-frequency phytoplankton observations against changes in the environment. In order to compare the IFCB results with conventional monitoring methods, filamentous cyanobacteria were enumerated from water samples using light microscopical analysis. Two common bloom forming filamentous cyanobacteria in the Baltic Sea, Aphanizomenon flosaquae and Dolichospermum spp. dominated the bloom, followed by an increase in Oscillatoriales abundance. The IFCB results compared well with the results of the light microscopical analysis, especially in the case of Dolichospermum. Aphanizomenon biomass varied slightly between the methods and the Oscillatoriales results deviated the most. Bloom formation was initiated as water temperature increased to over 15°C and terminated as the wind speed increased, dispersing the bloom. Community shifts were closely related to movements of the water mass. We demonstrate how using a high-frequency imaging flow cytometry application can help understand the development of cyanobacteria summer blooms.
  • Seppälä, Jukka (Finnish Environment Institute, 2009)
    Monographs of the Boreal Environment Research 34
    To obtain data on phytoplankton dynamics (abundance, taxonomy, productivity, and physiology) with improved spatial and temporal resolution, and at reduced cost, traditional phytoplankton monitoring methods have been supplemented with optical approaches. Fluorescence detection of living phytoplankton is very sensitive and not disturbed much by the other optically active components. Fluorescence results are easy to generate, but interpretation of measurements is not straightforward as phytoplankton fluorescence is determined by light absorption, light reabsorption, and quantum yield of fluorescence - all of which are affected by the physiological state of the cells. In this thesis, I have explored various fluorescence-based techniques for detection of phytoplankton abundance, taxonomy and physiology in the Baltic Sea.In algal cultures used in this thesis, the availability of nitrogen and light conditions caused changes in pigmentation, and consequently in light absorption and fluorescence properties of cells. The variation of absorption and fluorescence properties of natural phytoplankton populations in the Baltic Sea was more complex. Physical environmental factors (e.g. mixing depth, irradiance and temperature) and related seasonal succession in the phytoplankton community explained a large part of the seasonal variability in the magnitude and shape of Chlorophyll a (Chla)-specific absorption. Subsequent variations in the variables affecting fluorescence were large; 2.4-fold for light reabsorption at the red Chla peak and 7-fold for the spectrally averaged Chla-specific absorption coefficient for Photosystem II. In the studies included in this thesis, Chla-specific fluorescence varied 2-10 fold. This variability in Chla-specific fluorescence was related to the abundance of cyanobacteria, the size structure of the phytoplankton community, and absorption characteristics of phytoplankton.Cyanobacteria show very low Chla-specific fluorescence. In the presence of eukaryotic species, Chla fluorescence describes poorly cyanobacteria. During cyanobacterial bloom in the Baltic Sea, phycocyanin fluorescence explained large part of the variability in Chla concentrations. Thus, both Chla and phycocyanin fluorescence were required to predict Chla concentration.Phycobilins are major light harvesting pigments for cyanobacteria. In the open Baltic Sea, small picoplanktonic cyanobacteria were the main source of phycoerythrin fluorescence and absorption signal. Large filamentous cyanobacteria, forming harmful blooms, were the main source of the phycocyanin fluorescence signal and typically their biomass and phycocyanin fluorescence were linearly related. It was shown that for reliable phycocyanin detection, instrument wavebands must match the actual phycocyanin fluorescence peak well. In order to initiate an operational ship-of-opportunity monitoring of cyanobacterial blooms in the Baltic Sea, the distribution of filamentous cyanobacteria was followed in 2005 using phycocyanin fluorescence.Various taxonomic phytoplankton pigment groups can be separated by spectral fluorescence. I compared multivariate calibration methods for the retrieval of phytoplankton biomass in different taxonomic groups. During a mesocosm experiment, a partial least squares regression method gave the closest predictions for all taxonomic groups, and the accuracy was adequate for phytoplankton bloom detection. This method was noted applicable especially in the cases when not all of the optically active compounds are known.Variable fluorescence has been proposed as a tool to study the physiological state of phytoplankton. My results from the Baltic Sea emphasize that variable fluorescence alone cannot be used to detect nutrient limitation of phytoplankton. However, when combined with experiments with active nutrient manipulation, and other nutrient limitation indices, variable fluorescence provided valuable information on the physiological responses of the phytoplankton community. This thesis found a severe limitation of a commercial fast repetition rate fluorometer, which couldn’t detect the variable fluorescence of phycoerythrin-lacking cyanobacteria. For these species, the Photosystem II absorption of blue light is very low, and fluorometer excitation light did not saturate Photosystem II during a measurement.This thesis encourages the use of various in vivo fluorescence methods for the detection of bulk phytoplankton biomass, biomass of cyanobacteria, chemotaxonomy of phytoplankton community, and phytoplankton physiology. Fluorescence methods can support traditional phytoplankton monitoring by providing continuous measurements of phytoplankton, and thereby strengthen the understanding of the links between biological, chemical and physical processes in aquatic ecosystems.
  • Uronen, Pauliina (Finnish Environment Institute, 2007)
    Monographs of the Boreal Environment Research 28
    This study deals with algal species occurring commonly in the Baltic Sea: haptophyte Prymnesium parvum, dinoflagellates Dinophysis acuminata, D. norvegica and D. rotundata, and cyanobacterium Nodulariaspumigena. The hypotheses are connected to the toxicity of the species, to the factors determining toxicity, to the consequences of toxicity and to the transfer of toxins in the aquatic food web.Since the Baltic Sea is severely eutrophicated, the fast-growing haptophytes have potential in causing toxic blooms. In our studies, the toxicity (as haemolytic activity) of the haptophyte P. parvum was highest under phosphorus-limited conditions, but the cells were toxic also under nitrogen limitation and under nutrient-balanced growth conditions. The cellular nutrient ratios were tightly related to the toxicity. The stoichiometric flexibility for cellular phosphorus quota was higher than for nitrogen, and nitrogen limitation led to decreased biomass. Negative allelopathic effects on another algae (Rhodomonas salina) could be observed already at low P. parvum cell densities, whereas immediate lysis of R. salina cells occurred at P. parvum cell densities corresponding to natural blooms. Release of dissolved organic carbon from the R. salina cells was measured within 30 minutes, and an increase in bacterial number and biomass was measured within 23 h. Because of the allelopathic effect, formation of a P. parvum bloom may accelerate after a critical cell density is reached and the competing species are eliminated. A P. parvum bloom indirectly stimulates bacterial growth, and alters the functioning of the planktonic food web by increasing the carbon transfer through the microbial loop.Our results were the first reports on DSP toxins in Dinophysis cells in the Gulf of Finland and on PTX-2 in the Baltic Sea. Cellular toxin contents in Dinophysis spp. ranged from 0.2 to 149 pg DTX-1 cell-1 and from 1.6 to 19.9 pg PTX-2 cell-1 in the Gulf of Finland. D. norvegica was found mainly around the thermocline (max. 200 cells L-1), whereas D. acuminata was found in the whole mixed layer (max. 7 280 cells L-1). Toxins in the sediment trap corresponded to 1 % of DTX-1 and 0.01 % PTX-2 of the DSP pool in the suspended matter. This indicates that the majority of the DSP toxins does not enter the benthic community, but is either decomposed in the water column, or transferred to higher trophic levels in the planktonic food chain.We found that nodularin, produced by Nodularia spumigena, was transferred to the copepod Eurytemoraaffinis through three pathways: by grazing on filaments of small Nodularia, directly from the dissolved pool, and through the microbial food web by copepods grazing on ciliates, dinoflagellates and heterotrophic nanoflagellates. The estimated proportion of the microbial food web in nodularin transfer was 22-45 % and 71-76 % in our two experiments, respectively. This highlights the potential role of the microbial food web in the transfer of toxins in the planktonic food web.
  • Taipale, Sami J.; Kuoppamäki, Kirsi; Strandberg, Ursula; Peltomaa, Elina; Vuorio, Kristiina (SpringerLink, 2020)
    Hydrobiologia 847 21 (2020)
    Food quality is one of the key factors influencing zooplankton population dynamics. Eutrophication drives phytoplankton communities toward the dominance of cyanobacteria, which means a decrease in the availability of sterols and long-chain polyunsaturated fatty acids (EPA and DHA). The effects of different restoration measures on the nutritional quality of the phytoplankton community and subsequent impacts on zooplankton biomass have rarely been considered. We analyzed the nutritional quality of phytoplankton in the eutrophic Lake Vesijärvi in southern Finland over a 37-year period, and studied the impacts of two restoration measures, biomanipulation and hypolimnetic aeration, on the abundance of high-quality phytoplankton. We found that biomanipulation had a positive impact on the abundance of taxa synthesizing sterols, EPA, and DHA and, concurrently, on the biomass of the keystone species Daphnia. In contrast, hypolimnetic aeration did not result in such a beneficial outcome, manifested as a decrease in the abundance of Daphnia and frequent phytoplankton blooms dominated by cyanobacteria suggesting reduction in the nutritional quality of food for Daphnia. Our analysis shows that the determination of the nutritional value of algae and the contribution of essential fatty acids and sterols is an effective method to evaluate the success of various restoration measures.
  • Agge, Ursula (University of Helsinki, 1995)
  • Rinne, Ilkka; Melvasalo, Terttu; Niemi, Åke; Niemistö, Lauri (Vesihallitus. National Board of Waters, 1979)
    Vesientutkimuslaitoksen julkaisuja 34, 88-107
    Sinilevien typensidonta Itämeressä 1975 ja 1977.
  • Tokodi, Nada; Backovic, Damjana Drobac; Luji, Jelena; Šcekic, Ilija; Simic, Snežana; Đorđevic, Nevena; Dulic, Tamara; Miljanovic, Branko; Kitanovic, Nevena; Marinovic, Zoran; Savela, Henna; Meriluoto, Jussi; Svircev, Zorica (MDPI, 2020)
    Water 12 1 (2020)
    For 50 years persistent cyanobacterial blooms have been observed in Lake Ludoš (Serbia), a wetland area of international significance listed as a Ramsar site. Cyanobacteria and cyanotoxins can affect many organisms, including valuable flora and fauna, such as rare and endangered bird species living or visiting the lake. The aim was to carry out monitoring, estimate the current status of the lake, and discuss potential resolutions. Results obtained showed: (a) the poor chemical state of the lake; (b) the presence of potentially toxic (genera Dolichospermum, Microcystis, Planktothrix, Chroococcus, Oscillatoria, Woronichinia and dominant species Limnothrix redekei and Pseudanabaena limnetica) and invasive cyanobacterial species Raphidiopsis raciborskii; (c) the detection of microcystin (MC) and saxitoxin (STX) coding genes in biomass samples; (d) the detection of several microcystin variants (MC-LR, MC-dmLR, MC-RR, MC-dmRR, MC-LF) in water samples; (e) histopathological alterations in fish liver, kidney and gills. The potential health risk to all organisms in the ecosystem and the ecosystem itself is thus still real and present. Although there is still no resolution in sight, urgent remediation measures are needed to alleviate the incessant cyanobacterial problem in Lake Ludoš to break this ecosystem out of the perpetual state of limbo in which it has been trapped for quite some time.
  • Melvasalo, Terttu; Viljamaa, Hilkka (Vesihallitus, 1977)
    Vesientutkimuslaitoksen julkaisuja 19
    Tiivistelmä