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1
Content available remote Bioactive metabolites produced by Spirulina subsalsa from the Baltic Sea
EN
Cyanobacteria are known producers of compounds with possible medical applications. So far, the biotechnological potential of Spirulina subsalsa has been explored in few studies. They were mainly focused on the use of this cyanobacterium as a bioremediation agent. In our study, seven fractions from Baltic-derived S. subsalsa CCNP1310 were obtained and their cytotoxic effect on the T47D breast cancer cell line as well as inhibitory effects against elastase, trypsin, thrombin, chymotrypsin, and carboxypeptidase A were examined. Four fractions revealed a significant decrease in relative viability of cancer cells. Two inhibited the activity of chymotrypsin and one carboxypeptidase A, but at a moderate level. No effect was observed against other tested proteases. Active fractions were screened with liquid chromatography tandem mass spectrometry (LC-MS/MS) optimized for the detection of peptides, for preliminary characterization of bioactive compounds. We identified three groups of compounds which share the same fragment ions and are possibly linked with effects observed in conducted tests. Our research indicates for the first time that compounds produced by Baltic strain of S. subsalsa not only have high activity against T47D cancer cells but also seem to work selectively as they do not have strong inhibitory effect against the tested enzymes. That indicates the existing potential of the cyanobacterium to be used as a source of important cytotoxic agents.
EN
Cyanobacteria constitute a rich source of biologically active and structurally diverse compounds. The pharmacological potential of these compounds resides among others in their ability to control the proliferation and growth of cancer cell lines and potent disease-causing microbial agents. Despite recent scientific advances, the way these compounds interact with the body’s molecular structure are still unclear and science still has to discover how the cyanobacterial metabolites interact with cell structures and how cells react to them. In this project, we will study yet unexamined cyanobacterial metabolites, especially the compounds which act as chemical ligands for microRNA (miRNA) -binding sites, making them promising regulators (inhibitors) of gene networks that are involved in various diseases. We will first develop a stable cell line that constitutively expresses a unique miRNA reporter system. Then, we will conduct a screen on chemical compounds discovered in Baltic cyanobacteria to identify small molecules with inhibitory activity and specificity to MIR92b-3p, which has a significant impact on liver cell behavior in humans. We assume that a successful MIR92b-3p inhibitor will bind to the precursors of MIR92b-3p miRNA, disabling the action of either of the two processing enzymes involved in the biogenesis of any miRNA in a cell (Drosha or Dicer), thus affecting the MIR92b function. The discoveries made with these inhibitory chemical molecules could provide insight into the role of the MIR92 pathway in liver diseases and cancer, and possibly, if promising results appear, they may facilitate a strategy for treating some human diseases in the future.
PL
Warunkiem właściwego rozpoznania istniejącego ryzyka oraz skutków narażenia na działanie BMAA jest optymalizacja i walidacja technik ekstrakcji i detekcji. Takie badania powinny być prowadzone o odpowiedniej charakterystyce metrologicznej.
EN
In the current study we present the first report on the bioaccumulation of microcystins (MC) in zebra mussel Dreissena polymorpha from the eutrophic brackish water Curonian Lagoon. The bioaccumulation capacity was related to age structure of mussels and ambient environmental conditions. We also discuss the relevant implications of these findings for biomonitoring of toxic cyanobacteria blooms in the Curonian Lagoon and potential consequences for D. polymorpha cultivation activities considered for the futures as remediation measure. Samples for the analysis were collected twice per year, in June and September, in 2006, 2007 and 2008, from two sites within the littoral zone of the lagoon. The highest microcystin concentrations were measured in mussels larger than 30 mm length and sampled in 2006 (when a severe toxic cyanobacteria bloom occurred). In the following years, a consistent reduction in bioaccumulated MC concentration was noticed. However, certain amount of microcystin was recorded in mussel tissues in 2007 and 2008, when no cyanotoxins were reported in the phytoplankton. Considering high depuration rates and presence of cyanotoxins in the bottom sediments well after the recorded toxic blooms, we assume mechanism of secondary contamination when microcystin residuals could be uptaken by mussels with resuspended sediment particles.
EN
In this work, the authors examined the presence of cyanobacteria and cyanotoxins in 21 samples collected from fresh water bodies located in 5 provinces in Poland: Lublin (2), Podlasie (1), Pomerania (6), Warmia-Masuria (1) and Wielkopolska (11). In addition, to determine the general pattern of geographical distribution, frequency of cyanobacteria occurrence, and cyanotoxins production, the published data from 238 fresh water bodies in Poland were reviewed. On the basis of these collected results, we concluded that Planktothrix, Aphanizomenon, Microcystis and Dolichospermum were dominant. The general pattern in geographical distribution of the identified cyanobacterial genera was typical of other eutrophic waters in Europe. The production of cyanotoxins was revealed in 18 (86%) of the 21 samples analyzed in the present work and in 74 (75%) of the 98 total water bodies for which the presence of toxins had been examined. Among the 24 detected microcystin variants, [Asp3]MC-RR was most common. These results can be verified when more data from the less explored water bodies in the southern and eastern parts of Poland are available.
EN
A project was developed concerning the operational system of surveillance and the recording of episodic events in the Baltic Sea. In situ information was to be combined with multi-sensory satellite imagery to determine the extent of algal blooms, to track their evolution and that of rapid environmental events like hydrological fronts. The main element of the system was an autonomous Ferry Box module on a ferry operating between Gdynia and Karlskrona, automatically measuring temperature, salinity and chlorophyll a fluorescence. At pre-selected locations, discrete water samples were collected, which were subsequently analysed for their phytoplankton content, and algal hepato- and neurotoxins; they were also used in toxicity tests with Artemia franciscana.
EN
The effect of cyanobacterial blooms on the phytoplankton structure in the lowland Narew River (north-eastern Poland) was examined. The studies were carried out at stations situated at different distances from the eutrophic Siemianówka Dam Reservoir. In 2008, the investigated lowland reservoir and the outflowing river were characterized by the dominance of toxic cyanobacteria (from July to October). At a station situated 130 km below the dam, species composition in the river was very similar to that in the shallow reservoir. Planktothrix agardhii was the main and permanent dominant, both in limnoplankton and potamoplankton. The current study indicates that the eutrophic Siemianówka Dam Reservoir is the main and rich source of phytoplankton for the outflowing Narew River. Cyanobacteria were dominant in the river phytoplankton at all sampling stations, but their share in phytoplankton biomass gradually decreased with the distance from the dam. Chemical analysis revealed the presence of microcystins (MCs) in water samples collected from June to October. The toxins, mainly demethylated MC analogues, were detected at a long distance down the river, even 100 km from the dam. Maximum concentration of MCs (14.3 μg l-1) was measured on 13 October, 9.1 km below the dam.
EN
The Vistula Lagoon (southern Baltic Sea) is a shallow and highly eutrophic water body, with frequent blooms of cyanobacteria dominated by Microcystis and Anabaena species. Two Microcystis strains, MK10.10 and MAKR0205, isolated from the lagoon were characterised in this work. The morphology of the isolates differed significantly with respect to cell size and their ability to form aggregates. Based on the 16S rRNA sequence and 16S-23S internal transcribed spacer (ITS) sequence, both isolates were classified as Microcystis aeruginosa. However, only one isolate, MK10.10, possessed the mcy genes responsible for microcystin biosynthesis and only this strain produced microcystins. The effects of environmental factors, such as light, temperature and salinity, on toxin production turned out to be minor. Under the culture conditions used in the experiments, the biomass of the toxic MK10.10 was always lower. Hybrid quadrupole-time-of-flight liquid chromatography/tandem mass spectrometry (QTOF-LC/MS/MS) was used to elucidate the structure of the microcystin (MC) variants produced by MK10.10. Based on molecular ion and fragmentation spectra, the toxins were identified as MC-LR, MC-VR and MC-HIlR. Our study confirmed that some morphological criteria could be useful in preliminarily assessing the potential toxicity of a Microcystis bloom.
9
Content available remote Toxic cyanobacteria blooms in the Lithuanian part of the Curonian Lagoon
EN
The phenomenon of cyanobacteria (blue-green algae) blooms in the Baltic and the surrounding freshwater bodies has been known for several decades. The presence of cyanobacterial toxic metabolites in the Curonian Lagoon has been investigated and demonstrated for the first time in this work (2006-2007). Microcystis aeruginosa was the most common and widely distributed species in the 2006 blooms. Nodularia spumigena was present in the northern part of the Curonian Lagoon, following the intrusion of brackish water from the Baltic Sea; this is the first time that this nodularin-(NOD)-producing cyanobacterium has been recorded in the lagoon. With the aid of high-performance liquid chromatography (HPLC), four microcystins (MC-LR, MC-RR, MC-LY, MC-YR) and nodularin were detected in 2006. The presence of these cyanobacterial hepatotoxic cyclic peptides was additionally confirmed by enzyme-linked immunosorbent assay (ELISA) and protein phosphatase inhibition assay (PP1). Microcystin-LR, the most frequent of them, was present in every sample at quite high concentrations (from <0.1 to 134.2 žg dm-3). In 2007, no cyanobacterial bloom was recorded and cyanotoxins were detected in only 4% of the investigated samples. A comparably high concentration of nodularin was detected in the northern part of the Curonian Lagoon. In one sample dimethylated MC-RR was also detected (concentration 7.5 žg dm-3). full, complete article (PDF - compatibile with Acrobat 4.0), 289.5 kB
10
Content available remote Do toxic cyanobacteria blooms pose a threat to the Baltic ecosystem?
EN
Cyanobacteria, otherwise known as blue-green algae, are oxygenic, photosynthetic prokaryotes. They occur naturally in many fresh, marine and brackish waters worldwide and play an important role in global carbon and nitrogen cycles. In their long history, cyanobacteria have developed structures and mechanisms that enable them to survive and proliferate under different environmental conditions. In the Baltic Sea, the mass development of cyanobacteria is compounded by a high level of eutrophication. The dominant species in the Baltic, the filamentous Aphanizomenon flos-aquae and Nodularia spumigena, can fix dissolved atmospheric N2, as a result of which they can outcompete other phytoplankton organisms. Heterocystous, filamentous cyanobacteria also make a significant contribution to the internal nutrient loading in the Baltic. The blooms of N. spumigena are of particular concern, as this cyanobacterium produces nodularin (NOD), a hepatotoxic peptide. The concentration of the toxin in the sea is regulated mainly by dilution with uncontaminated water, photolysis, sorption to sediments and microbial degradation. The transfer of the toxin in the Baltic trophic chain through zooplankton, mussels, fish and birds has been reported, but biodilution rather than bioconcentration has been observed. Cyanobacterial blooms are thought to pose a serious threat to the ecosystem. Their harmful effects are related to the occurrence of a high biomass, oxygen depletion, a reduction in biodiversity, and the production of toxic metabolites.
EN
Microcystins (MCs) and structurally related nodularins (NODs) are hepatotoxic cyclic peptides produced by bloom-forming cyanobacteria. These toxins have been implicated in the deaths of wild and domestic animals as well as in incidents of human illness. Cyanobacterial toxins occurring in the fresh and brackish waters of the Pomeranian Province, northern Poland were characterized in this study. Water samples collected from seven lakes in August and September 2005 were analysed by high performance liquid chromatography (HPLC), enzyme linked immunosorbent assay (ELISA) and protein phosphatase inhibition assay (PPIA). Cyanobacterial toxins present in field samples and in an isolated strain of Planktothrix agardhii were also characterized by liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). In most of the fresh water samples MC-LR, MC-RR and MC-YR dominated. In the lakes where P. agardhii was most abundant demethylated microcystin variants tentatively identified as [D-Asp3]MC-LR, [D-Asp3]MC-YR and [D-Asp3]MC-RR, were found. Total concentrations of the toxins measured by HPLC ranged from 0.1 žg l-1 to 305.4 žg l-1. Nodularia spumigena bloom samples were collected from brackish waters of the Gulf of Gdańsk, southern Baltic, and LC-ISP-MS/MS of extract from these revealed the presence of two geometrical isomers of linear nodularin and nodularin variant with aspartic acid methyl ester [MeAsp1(OMe)]NOD.
EN
The most striking aspect of eutrophication in the Baltic are the summer blooms of cyanobacteria. Some of the blooms are toxic to marine organisms and poisonous to people. Our studies, conducted over the last three decades, report on mass occurrences of Aphanizomenon flos-aquae (L.) Ralphs and Nodularia spumigena Mertens. It is generally assumed that cyanobacterial blooms in the Baltic Sea are stimulated by the low ratio of N:P and initiated by high water temperatures. The mean annual value of this ratio in the Gulf of Gdańsk, since 1981, is 7:1-8:1, with the lowest values, of about 4, being seen in July when the cyanobacterial blooms begin. During three years of observations (1992-1994) the smallest number of recorded taxa was reported in 1993, concurrent with the lowest water temperature (16°C in summer). In August 1994, when the temperature increased to 22°C, a huge bloom was seen. Nodularia spumigena was very abundant in that bloom, and nodularin concentration of 2.59 mg toxin per g dry weight of bloom sample was recorded. A similar situation has also been observed in the years 2003-2006.
13
Content available remote Nodularyny i inne toksyny produkowane przez cyjanobakterie (sinice)
EN
Cyanobacteria are photosynthetic prokaryotes that produce a wide range of secondary metabolites. Part of them is toxic or shows bioactivity in other organisms, including mammals . The main classes of cyanobacterial toxins comprise of hepatotoxins, neurotoxins, cytotoxins, dermatotoxins and lipopolysaccharides. Hepatotoxins, microcystins and nodularins are the most common cyanotoxins. Microcystins, the cyclic heptapeptides are produced by freshwater cyanobacteria of the genera Microcystis, Anabaena, Planktothrix (Oscillatoria), Nostoc, Hapalosiphon and Anabaenopsis. Nodularin (NOD-R) the cyclic pentapeptide hepatotoxin is produced by brackish water cyanobacterium Nodularia spumigena. Microcystins and nodularins are extremely toxic due to their action on type 1 and 2A protein phosphatase enzymes that play a key role in the control of cellular meta-bolism. The main groups of neurotoxins produced by cyanobacteria include anatoxin-a, anatoxin-a(s), saxitoxins and the recently identified B-N-methylamino--L-alanine (BMAA). The latter has been reported to biomagnify within the Guam ecosystem and was suggested to be a possible cause of the amyotrophic lateral sclerosis/parkinsonism-dementia complex (ALS/PDC). In the Baltic Sea N. spumigena is the main toxic and bloom-forming cyanobacterial species [7]. Nodularin concentration can temporarily reach over 20 mg dm-3. The toxin accumulates in different elements of the Baltic ecosystem, including sediments, mussels and fish. Apart from NOD-R, minor amounts of other NOD analogues have been characterized in N. spumigena cells: geometrical isomers, linear forms, three demethylated analogues and three analogues with additional methyl group. Nodularin is characterized by high stability. The loss of the toxin in water is mainly due to degradation by the naturally occurring bacterial community. However, the UV radiation as well as sorption on sediments and sus-pended particles has also some impact on nodularin concentration. In organisms microcystins are detoxified by conjugation with activated glutathione, however, the pathway of nodularin biotransformation has not been revealed yet.
EN
Nodularia spumigena Mertens, Aphanizomenon flos-aquae (L.) Ralfs and some species of the genus Anabaena are the dominant cyanobacterial taxa occurring in the Gulf of Gdańsk. The heterocystous cyanobacteria use dissolved molecular N2 as an additional nitrogen source, and this allows them to bloom during the summer when growth of other phytoplankton species is normally nitrogen-limited. Although cyanobacterial blooms have been reported in the Baltic Sea since the mid-19th century, the extent and intensity of blooms have recently increased due to anthropogenic sources of eutrophication. Increased river phosphorus input and changes in the phosphorus to nitrogen ratio are implicated as causal factors. After us the initial cause of the cyanobacterial bloom is a low N:P ratio, which indicates phosphorus excess, i.e. favourable nutrient conditions for nitrogen-fixing algae. An N:P ratio of 10 has been considered an approximate value for the N:P requirements of Baltic phytoplankton. For several years this ratio has been lower than 10. The mean annual value of the N:P ratio for the water of the Gulf of Gdańsk ranged from 3 to 7. Differences in the intensity of blooms observed in different years could be linked to temperature. During hot summers, when the seawater temperature increased to 20°C, large blooms were noted. For the cyanobacterial blooms in the Baltic Sea, the low N:P ratio is the primary factor and high temperature is a starting point.
15
Content available BMAA i inne neurotoksyny cyjanobakterii
PL
Cyjanobakterie są bogatym źródłem związków biologicznie aktywnych. Wiele z nich znalazło praktyczne zastosowanie w medycynie, kosmetyce i rolnictwie. Te same organizmy produkują również metabolity wtórne o działaniu toksycznym. Należą do nich hepatotoksyny, dermatotoksyny oraz neurotoksyny. Neurotoksyny (anatoksyny i saksitoksyny), ze względu na niską wartość dawki letalnej należą do najsilniejszych toksyn naturalnych. Do niedawna sądzono, że zakwity cyjanobakterii produkujących związki o działaniu neurotoksycznym występują znacznie rzadziej niż zakwity gatunków produkujących hepatotoksyny. Ostatnio jednak odkryto, u wielu cyjanobakterii, obecność neurotoksycznego aminokwasu BMAA (ß-Nmetyloamino- L-alanina). Przypuszcza się, że związany jest on z przypadkami choroby Alzheimera zarejestrowanymi w Kanadzie.
EN
Cyanobacteria are a rich source of biologically active compounds. Many of them have been practically used in medicine, cosmetics and agriculture industries. The same organisms also produce secondary metabolites that act as toxins. This group of toxins consists from hepatotoxins, dermatotoxins,and neurotoxins. Due to low lethal dose value the neurotoxins (anatoxins and saxitoxins) are considered to be the most toxic natural substances. Until recently, it has been thought that cyanobacteria species producing compounds with neurotoxic properties occur considerably more rarely than blooms of species producing hepatotoxins. However, in many cyanobacteria the presence of neurotoxic BMAA (ß-N-methylamine-Lalanine) has been lately discovered. It is supposed that BMAA may be related to Alzheimer disease cases recorded in Canada.
EN
Cyanobacteria (blue-green algae), photosynthetic prokaryotes, are essential elements of aquatic ecosystems. They produce a great variety of secondary metabolites; some of which have potentially useful pharmaceutical properties as anti-tumour, antibacterial and antiviral agents. Some species of cyanobacteria form blooms and become dominant over other forms of aquatic life. Blooms can deteriorate water quality in a variety of ways. Blooms formed by toxic species are the most harmful, as they can cause poisoning and death of organisms that come into contact with them. In this review, the structure and activity of cyanobacterial toxins are described. The toxins are classified into: hepatotoxins, neurotoxins, dermatotoxins and endotoxic lipopolysaccharides. Hepatotoxic cyclic pentapeptides, microcystins and nodularins, are the most common cyanobacterial toxins that have been identified in strains of Microcystis, Anabaena, Nodularia, Planktothrix (Oscillatoria), Nostoc, Hapalosiphon and Anabaenopsis. Cylindrospermopsin, another cyanobacterial hepatotoxin, is produced mainly by Cylindrospermopsis raciborskii. There are several neurotoxins produced by the cyanobacterial genera Anabaena, Aphanizomenon, Planktothrix and Cylindrospermopsis. Based on their activity, these neurotoxins were classified into anatoxin-a, anatoxin-a(S) and saxitoxins. BMAA is a novel cyanobacterial neurotoxin implicated in the ALS/PDC syndrome in the Chamorro people of Guam. The occurrence and harmful effects of cyanobacterial dermatotoxins and endotoxic lipopolysaccharides are less well recognised.
EN
In the Baltic Sea, summer blooms of the filamentous, nitrogen-fixing cyanobacterium Nodularia spumigena are favoured by high P concentrations at low N:P ratios and a salinity range of 5-13 PSU. The blooms are initiated by calm and sunny weather, an elevated surface water temperature and thermal stratification. The mass occurrence of N. spumigena in coastal waters is a matter of special concern, as the cyanobacterium produces nodularin, a potent pentapeptide hepatotoxin. In the Gulf of Gdansk, the large-scale occurrence of N. spumigena was recorded for the first time in 1994. Blooms of a similar intensity occurred in 2001, 2003 and 2004. Nodularin concentrations in freeze-dried bloom samples varied from 0.01 to 4.01 mg g-1 d.w. In the coastal waters of the Gulf of Gdańsk, cell-bound nodularin concentrations in 2004 and 2005 attained maxima of 25852 š 107 žg dm-3 and 3964 š 125 žg dm-3, respectively. Microscopic analysis revealed the presence of diverse N. spumigena forms, with the dominance of curved filaments in bloom samples. The results of in situ studies and remote sensing measurements indicate a high frequency and intensity of cyanobacterial blooms in the Gulf of Gdańsk in the last ten years.
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