| factors influencing the growth of microcystis aeruginosa kutz, emend, elenkin. | | 1960 | 13788092 |
| the standardization of a molecular biology method to verify the presence of microcystis aeruginosa. | | 2003 | 14535409 |
| pcr-based identification of microcystin-producing genotypes of different cyanobacterial genera. | microcystins are harmful hepatotoxins produced by many, but not all strains of the cyanobacterial genera anabaena, microcystis, anabaena, planktothrix, and nostoc. waterbodies have to be monitored for the mass development of toxic cyanobacteria; however, because of the close genetic relationship of microcystin-producing and non-producing strains within a genus, identification of microcystin-producers by morphological criteria is not possible. the genomes of microcystin-producing cells contain mc ... | 2003 | 14551674 |
| high-resolution differentiation of cyanobacteria by using rrna-internal transcribed spacer denaturing gradient gel electrophoresis. | for many ecological studies of cyanobacteria, it is essential that closely related species or strains can be discriminated. since this is often not possible by using morphological features, cyanobacteria are frequently studied by using dna-based methods. a powerful method for analysis of the diversity and dynamics of microbial populations and for checking the purity and affiliation of cultivated strains is denaturing gradient gel electrophoresis (dgge). we realized high-resolution discrimination ... | 2003 | 14602623 |
| application of real-time pcr for quantification of microcystin genotypes in a population of the toxic cyanobacterium microcystis sp. | the cyanobacterium microcystis sp. frequently develops water blooms consisting of organisms with different genotypes that either produce or lack the hepatotoxin microcystin. in order to monitor the development of microcystin (mcy) genotypes during the seasonal cycle of the total population, mcy genotypes were quantified by means of real-time pcr in lake wannsee (berlin, germany) from june 1999 to october 2000. standard curves were established by relating cell concentrations to the threshold cycl ... | 2003 | 14602633 |
| changes in cyanoprokaryote populations, microcystis morphology, and microcystin concentrations in lake elphinstone (central queensland, australia). | lake elphinstone is a tropical inland water body in the far north of the fitzroy catchment in central queensland, australia, and has experienced recurrent toxic cyanoprokaryote blooms since 1997. this article reports on an examination of the environmental conditions of the lake and the concurrent cyanoprokaryote species together with their toxicity. the lake was sampled three times during periods of high cyanoprokaryote cell concentrations. successive changes in the dominant microcystis species ... | 2003 | 14608610 |
| [antibacterial activity of pure cultures of cyanobacteria and algae]. | pure cultures of microcystis aeruginosa, platymonas viridis and nephrochloris salina have been grown on the media with different nitrogen and phosphorus content. their supernatants and pellets, as well as lipid complex, terpene fraction and some its components from m. aeruginosa had selective antibacterial characteristics. the increase of nitrogen content in the medium correlated with the intensification (m. aeruginosa, n. salina) or conservation (p. viridis) of bactericidal activity. the pellet ... | 2003 | 14618789 |
| dynamics of microcystins-lr and -rr in the phytoplanktivorous silver carp in a sub-chronic toxicity experiment. | a sub-chronic toxicity experiment was conducted to examine tissue distribution and depuration of two microcystins (microcystin-lr and microcystin -rr) in the phytoplanktivorous filter-feeding silver carp during a course of 80 days. two large tanks (a, b) were used, and in tank a, the fish were fed naturally with fresh microcystis viridis cells (collected from a eutrophic pond) throughout the experiment, while in tank b, the food of the fish were m. viridis cells for the first 40 days and then ch ... | 2004 | 14638304 |
| quantitative real-time pcr for determination of microcystin synthetase e copy numbers for microcystis and anabaena in lakes. | cyanobacterial mass occurrences in freshwater lakes are generally formed by anabaena, microcystis, and planktothrix, which may produce cyclic heptapeptide hepatotoxins, microcystins. thus far, identification of the most potent microcystin producer in a lake has not been possible due to a lack of quantitative methods. the aim of this study was to identify the microcystin-producing genera and to determine the copy numbers of microcystin synthetase gene e (mcye) in lake tuusulanjärvi and lake hiide ... | 2003 | 14660378 |
| reversed-phase liquid chromatographic-mass spectrometric determination of microcystin-lr in cyanobacteria blooms under alkaline conditions. | reversed-phase hplc coupled to the atmospheric pressure ionization-electrospray ionization (api-esi) ms was used for microcystin-lr detection and quantitation in samples of dried microcystis aeruginosa cells. an alkaline linear gradient (20 mmol/l ammonium hydroxide-acetonitrile, ph 9.7) was used for elution of the toxic peptides. limit of detection was 1 microg/ml (20 ng per injection) in the scan mode of ms and 0.1 microg/ml (2 ng per injection) in the case of selective ion monitoring. | 2004 | 14698272 |
| dynamics of microcystin-degrading bacteria in mucilage of microcystis. | to reveal the process of degradation of hepatotoxic microcystin produced in microcystis cells during the microcystis bloom period, we used fluorescence in situ hybridization (fish) to analyze the population dynamics of microcystin-degrading bacteria in microcystis mucilage. we designed and applied an oligonucleotide probe targeted to the 16s rrna sequence of strain y2 of a microcystin-degrading bacterium (mcd-bacterium), which was isolated from lake suwa, japan. in both the 1998 and 1999 tests, ... | 2003 | 14708752 |
| intracellular phosphorus metabolism of microcystis aeruginosa under various redox potential in darkness. | phosphorus metabolism of microcystis aeruginosa was studied under gradient redox potential from 252 mv to -70 mv in darkness. the release of phosphorus occurred in all the treatments, and this process was accelerated in darkness when the redox potential was lowered. low redox potential in darkness stimulated the accumulation of polyphosphate (polyp) and the degradation of polyglucose. the synthesis of polyp delayed the decrease of intracellular orthophosphate. the death of m. aeruginosa was slow ... | 2003 | 14717456 |
| [kinetics and mechanism of removing microcystis aeruginosa using clay flocculation]. | twenty-six natural clays were studied for their kinetics of flocculating and removing algal cells of microcystis aeruginosa. according to the 8 h equilibrium removal efficiencies and removal rates at a clay-loading of 0.7 g.l-1, all the 26 clays were classified into three categories. type-i clay, which includes talc, ferric oxide, sepiolite, ferroferric oxide, and kaolinite, has an equilibrium removal efficiency greater than 90%, a t50 (time needed to remove 50% of the algae) of less than 30 min ... | 2003 | 14719252 |
| salicylate biodegradation by various algal-bacterial consortia under photosynthetic oxygenation. | four green microalgae (chlorella sorokiniana, chlorella vulgaris, scenedesmus obliquus and selenastrum capricornutum), a wild bolivian microalga strain and two cyanobacteria (anabaena catenula and microcystis aeruginosa) were compared for tolerance to salicylate, o2 production capacity and ability to support salicylate degradation by a ralstonia basilensis strain in symbiotic microcosms with the microalgae. microcystis aeruginosa had the highest tolerance to salicylate at 500 mg l(-1) and 1500 m ... | 2003 | 14719825 |
| freshwater phytoplankton quantification by chlorophyll a: a comparative study of in vitro, in vivo and in situ methods. | standard iso method for chlorophyll a quantification (extraction into ethanol, spectrophotometrical quantification at 665 and 750 nm), spectrofluorometry (reader for 96 wells, excitation 410 nm, emission 670 nm), and a submersible fluorescence probe for in situ phytoplankton quantification (excitation 410, 525, 570, 590, and 610 nm, emission 685 nm) were compared in different freshwater environments-reservoirs and rivers. the iso method is accepted as a standard method but requires sample handli ... | 2004 | 14723919 |
| differentiation of nostoc flagelliforme and its neighboring species using fatty-acid profiling as a chemotaxonomic tool. | in this study, fatty-acid content and patterns were analyzed in order to distinguish nostoc flagelliforme, an edible terrestrial cyanobacterium, from other nostoc species and representatives typical of its close neighbors (genera anabaena, microcystis, and synechococcus). according to the kenyon-murata classification system, all the nostoc species were assigned to group ii due to the presence of c18:2n3 and c18:3n3, and the absence of c18:3n6. hierarchical cluster analysis was also employed to s ... | 2003 | 14756530 |
| permeabilizing effects of sub-inhibitory concentrations of microcystin on the growth of escherichia coli. | microcystin, a cyanotoxin produced by microcystis aeruginosa, lacks potent antibacterial activity. when tested in combination, in vitro, inhibitory values for a range of hydrophobic antibiotics were significantly reduced in the presence of at least 1/20 x the minimum inhibitory concentration of microcystin. the degree of inhibition was equivalent to that of a well-characterised permeabilizing agent, polymyxin b nonapeptide. the permeabilizing ability of sub-inhibitory concentrations of microcyst ... | 2004 | 14757235 |
| characteristics of microcystin production in the cell cycle of microcystis viridis. | the correlation between the content of three microcystins (types lr, rr and yr) and the cell cycle of an axenic strain of microcystis viridis, nies-102, was investigated under conditions of high (16 mg l(-1)) and low (1.0 mg l(-1)) nitrate (no(3)-n) concentrations. each phase of the cell cycle was identified using a flow cytometer equipped with a 488-nm argon laser using sytox green dye, which binds specifically to nucleic acids and can be exited by the wavelength (ex/em: 504/523 nm on dna). mic ... | 2004 | 14758590 |
| extraction of cyanobacterial endotoxin. | to simplify our efforts in acquiring toxicological information on endotoxins produced by cyanobacteria, a method development study was undertaken to identify relatively hazard-free and efficient procedures for their extraction. one article sourced and two novel methods were evaluated for their ability to extract lipopolysaccharides (lpss) or endotoxins from cyanobacteria. the limulus polyphemus amoebocyte lysate (lal) assay was employed to compare the performance of a novel method utilizing a 1- ... | 2004 | 14758595 |
| genes coding for hepatotoxic heptapeptides (microcystins) in the cyanobacterium anabaena strain 90. | the cluster of microcystin synthetase genes from anabaena strain 90 was sequenced and characterized. the total size of the region is 55.4 kb, and the genes are organized in three putative operons. the first operon (mcya-mcyb-mcyc) is transcribed in the opposite direction from the second operon (mcyg-mcyd-mcyj-mcye-mcyf-mcyi) and the third operon (mcyh). the genes mcya, mcyb, and mcyc encode nonribosomal peptide synthetases (nrps), while mcyd codes for a polyketide synthase (pks), and mcyg and mc ... | 2004 | 14766543 |
| symptoms of hay fever caused by algae. ii. microcystis, another form of algae producing allergenic reactions. | | 1951 | 14800202 |
| [effect of temperature on the translocation of exogenous 32p in water column, microcystis aeruginosa and sediments]. | effect of temperature on the translocation of exogenous phosphorus in the simulative ecosystem composing of water, microcystis aeruginosa and sediments was studied with the method of phosphorus isotope tracer. exogenous 32p was initially distributed rapidly in the ecosystems in a mode of physical chemistry, irrespective of the influence of different temperature. then, the translocation of 32p was significantly affected by the growth of m. aeruginosa in the ecosystem. relatively high temperature ... | 2003 | 14997658 |
| enantioselective syntheses and biological studies of aeruginosin 298-a and its analogs: application of catalytic asymmetric phase-transfer reaction. | aeruginosin 298-a was isolated from the freshwater cyanobacterium microcystis aeruginosa (nies-298) and is an equipotent thrombin and trypsin inhibitor. a variety of analogs were synthesized to gain insight into the structure-activity relations. we developed a versatile synthetic process for aeruginosin 298-a as well as several attractive analogs, in which all stereocenters were controlled by catalytic asymmetric phase-transfer reaction promoted by two-center asymmetric catalysts and catalytic a ... | 2004 | 15004282 |
| the gas vesicle gene cluster from microcystis aeruginosa and dna rearrangements that lead to loss of cell buoyancy. | microcystis aeruginosa is a planktonic unicellular cyanobacterium often responsible for seasonal mass occurrences at the surface of freshwater environments. an abundant production of intracellular structures, the gas vesicles, provides cells with buoyancy. a 8.7-kb gene cluster that comprises twelve genes involved in gas vesicle synthesis was identified. ten of these are organized in two operons, gvpa(i)a(ii)a(iii)cnjx and gvpkfg, and two, gvpv and gvpw, are individually expressed. in an attempt ... | 2004 | 15060038 |
| [sampling method adapted for colonial cyanobacteria in a lake environment. case study of microcystis aeruginosa in the grangent reservoir (loire, france)]. | new method of sampling adapted to colonial cyanobacteria was developed on the grangent reservoir (loire, france). these prokaryotes were sampled using a filtering pump and were counted at laboratory under epifluorescence microscope. this method allowed us to follow the annual cycle of microcystis aeruginosa, since benthic spring recruitment (cyanobacteria being used as inoculum) until autumnal sedimentation, and even revealed the presence of this cyanobacterian species in winter in the epilimnio ... | 2004 | 15060981 |
| comprehensive analysis system using liquid chromatography-mass spectrometry for the biosynthetic study of peptides produced by cyanobacteria. | microcystins are hepatotoxic heptapeptides and general tumor promoters produced by several species of the genera microcystis, anabaena, oscillatoria and nostoc. they are non-ribosomally synthesized via a mixed polyketide synthase/non-ribosomal peptide synthetase system called microcystin synthetase. we have carried out the detection, isolation and structural determination of non-toxic peptides produced together with microcystins by toxic cyanobacteria, which are classified into several groups on ... | 2004 | 15072295 |
| determination of toxic cyclic heptapeptides by liquid chromatography with detection using ultra-violet, protein phosphatase assay and tandem mass spectrometry. | microcystins, toxic cyclic heptapeptides and nodularin-r, a toxic cyclic pentapeptide, were determined using liquid chromatography (lc) with detection using photo-diode array ultra-violet (pda-uv) and protein phosphatase (pp) assay. positive fractions were analysed for toxins using collision-induced dissociation (cid) and tandem ms/ms experiments which were carried out simultaneously using electrospray ion-trap instrumentation. reversed-phase liquid chromatography (lc) using an acetonitrile/wate ... | 2004 | 15081782 |
| occurrence of copper resistant mutants in the toxic cyanobacteria microcystis aeruginosa: characterisation and future implications in the use of copper sulphate as algaecide. | freshwater toxic cyanobacteria are an increasing problem to human and animal health. control of cyanobacteria in water supply reservoirs involves the use of algaecides, such as copper sulphate, usually in a repetitive way. repercussions of recurrent algaecide treatments on cyanobacteria population dynamics remain still unknown. we studied the adaptation of cyanobacteria to lethal doses of copper sulphate by using microcystis aeruginosa as an experimental model. a fluctuation analysis demonstrate ... | 2004 | 15087203 |
| the algal community as an indicator of the trophic status of lake patzcuaro, mexico. | an evaluation of water quality and phytoplankton composition position was carried out in order to determine the trophic conditions of lake patzcuaro (2035 m above sea level), a high altitude tropical lake. temperatures ranged from 15 to 23 degrees c. total phosphorus and inorganic nitrogen showed a seasonal variation; highest values coincided with the rainy season (0.48 and 2.1 mg litre(-1), respectively). dissolved oxygen ranged from 2 to 7.9 mg litre(-1) at the surface and from 0.6 to 7.3 mg l ... | 1993 | 15091845 |
| biological treatment of wastewater by selected aquatic plants. | pollutant-removal efficiency of certain macrophytes and algae, such as eichhornia crassipes, microcystis aeruginosa, scenedesmus falcatus, chlorella vulgaris and chlamydomonas mirabilis, has been tested in laboratory conditions to evaluate their potential role in wastewater treatment. sewage of varanasi city, mixed with the effluents of about 1200 small-scale industries, was used for the tests. the investigation was performed in three stages i.e. a water hyacinth culture followed by an algal cul ... | 1991 | 15092171 |
| first report of a microcystin-containing bloom of the cyanobacteria microcystis spp. in lake oubeira, eastern algeria. | lake oubeira has been used as the main source of drinking water for many communities in the east of algeria. in this lake, nutrient loading coupled with year-round warm weather favors the growth of cyanobacteria, several of which can produce cyanotoxins, especially the potent liver toxins called microcystins (mcysts). the present study evaluated microcystin levels and characterized the different microcystin variants present in the raw water during a 17-month period (april 2000-september 2001), a ... | 2004 | 15106670 |
| occurrence and elimination of cyanobacterial toxins in two australian drinking water treatment plants. | in australian freshwaters, anabaena circinalis, microcystis spp. and cylindrospermopsis raciborskii are the dominant toxic cyanobacteria. many of these surface waters are used as drinking water resources. therefore, the national health and medical research council of australia set a guideline for mc-lr toxicity equivalents of 1.3 microg/l drinking water. however, due to lack of adequate data, no guideline values for paralytic shellfish poisons (psps) (e.g. saxitoxins) or cylindrospermopsin (cyn) ... | 2004 | 15109885 |
| changes in microcystin production by microcystis aeruginosa exposed to phytoplanktivorous and omnivorous fish. | with direct exposure to phytoplanktivorous fish (hypophthalmichthys molitrix), increased mass-specific microcystin production occurred in three monoclonal microcystis aeruginosa strains (nies 44, 88 and 99). total mass-specific microcystin content of nies 44 exposed to h. molitrix was over 50 times higher than controls (a mean value of 16.2 microgg(-1)-dry cell in controls versus 878.6 microgg(-1)-dry cell in treatments). up to nine times higher microcystin levels were detected in nies 88 expose ... | 2004 | 15110469 |
| [proximate and remote results of ureterosigmoidostomy with creation of mainz pouch ii and hasan reservoirs]. | the aim of the study was analysis of short- and long-term results of treating patients operated with intestinal replacement of the urinary bladder by mintz pouch ii and hasan. thirty-two ureterosigmostomies with creation of the reservoir from the rectosigmoid angle (17 mintz pouch ii and 15 abol-enein operations) were made from 1997-2002. the age of the patients ranged from 16 to 73, the follow-up was 12-72 months. the operation was indicated in infiltrative cancer of the urinary bladder, microc ... | 2004 | 15114743 |
| growth and phosphate uptake kinetics of microcystis aeruginosa under various environmental conditions. | growth and uptake of exogenous phosphate by microcystis aeruginosa in batch culture under different temperature, photoperiod, and turbulence were studied by the method of phosphate isotope tracer. relatively high temperature, long photoperiod and strong turbulence increased the cell density of m. aeruginosa in these batch cultures. the initial rapid uptake of phosphate by m. aeruginosa was independent of the temperature, photoperiod, and turbulence. similarly, maximum exogenous phosphate uptake ... | 2004 | 15137657 |
| molecular detection of genes responsible for cyanobacterial toxin production in the genera microcystis, nodularia, and cylindrospermopsis. | cyanobacteria are ubiquitous in the freshwater environment. their success as a group in a wide range of aquatic habitats has been attributed to their unique physiological characteristics and their high adaptive ability over a wide range of environmental conditions. they are capable of reaching very high biomass levels, often dominating the other aquatic biota, and under some circumstances can accumulate near the water surface, producing scums. such cyanobacterial "blooms" are of particular conce ... | 2004 | 15156033 |
| biosorption of uranium by lake-harvested biomass from a cyanobacterium bloom. | the aim of this work was to study some basic aspects of uranium biosorption by powdered biomass of lake-harvested cyanobacterium water-bloom, which consisted predominantly of microcystis aeruginosa. the optimum ph for uranium biosorption was between 4.0 and 8.0. the batch sorption reached the equilibrium within 1 h. the isotherm fitted the freundlich model well. although the langmuir model fitted the experiment data well at ph 3.0, 5.0 and 7.0, it did not fit at ph 9.0 and 11.0 at all. this impl ... | 2004 | 15158512 |
| the role of reactive oxygen species in microcystin-lr-induced dna damage. | microcystins are cyclic heptapeptides produced by different freshwater cyanobacterial species such as microcystis aeruginosa. they have been shown to induce dna damage in vitro and in vivo, however, the mechanisms of their genotoxic activity remain unclear. with the comet assay we demonstrate that, in human hepatoma hepg2 cells, microcystin-lr (mclr) induced dna strand breaks which were transiently present and probably produced during the cellular repair of mclr-induced dna damage. digestion of ... | 2004 | 15158564 |
| on the phytoplankton of awba reservoir, ibadan, nigeria. | the physico-chemical characteristics and phytoplankton of awba reservoir in the university of ibadan, nigeria, were monitored to determine the impact of eutrophication on phytoplankton composition. the principal component analysis identified three major components influencing the physicochemistry of the water, namely trace metals, dissolved oxygen and ionic composition. comparative analysis with a previous study showed a phenomenal increase in zinc, copper and iron levels over a 10-year period. ... | 2003 | 15162685 |
| diversity and distribution of microcystis (cyanobacteria) oligopeptide chemotypes from natural communities studied by single-colony mass spectrometry. | microcystis sp. has been recognized in recent years as a producer of a high number of secondary metabolites. among these, peptides that are produced by the non-ribosomal peptide synthetase pathway often show bioactivity or are toxic to humans. the production of particular peptides is specific for individual microcystis clones, allowing their characterization as chemotypes by analysing the peptidome. the authors studied the in situ diversity of peptides and chemotypes in microcystis communities f ... | 2004 | 15184565 |
| development of oligonucleotide primers for the detection of harmful microcystis in water. | | 2004 | 15199976 |
| kinetic studies on the combined effects of lanthanum and cerium on the growth of microcystis aeruginosa and their accumulation by m. aeruginosa. | | 2004 | 15199984 |
| kinetic studies on the effects of organophosphorus pesticides on the growth of microcystis aeruginosa and uptake of the phosphorus forms. | | 2004 | 15199995 |
| toxic and nontoxic microcystis colonies in natural populations can be differentiated on the basis of rrna gene internal transcribed spacer diversity. | assessing and predicting bloom dynamics and toxin production by microcystis requires analysis of toxic and nontoxic microcystis genotypes in natural communities. we show that genetic differentiation of microcystis colonies based on rrna internal transcribed spacer (its) sequences provides an adequate basis for recognition of microcystin producers. consequently, ecological studies of toxic and nontoxic cyanobacteria are now possible through studies of rrna its genotypic diversity in isolated cult ... | 2004 | 15240273 |
| acute effects of microcystis aeruginosa from the patos lagoon estuary, southern brazil, on the microcrustacean kalliapseudes schubartii (crustacea: tanaidacea). | toxic blooms of the cyanobacterium microcystis aeruginosa, a microcystin producer, have been observed in the past two decades in the patos lagoon estuary (southern brazil). this cyanobacterium reaches the estuary from northern waters and accumulates as toxic blooms in the shallow margins of the environment. microcystins are phosphatase (pp1 and pp2a) inhibitors and cause animal death via alteration of the liver cell cytoskeletons and intrahepatic hemorrhage. the massive accumulation of toxic mat ... | 2004 | 15253043 |
| effect of 1.7 mhz ultrasound on a gas-vacuolate cyanobacterium and a gas-vacuole negative cyanobacterium. | ultrasonic signals propagated through medium were directly applied to unicellular cyanobacterium cell surfaces to investigate the biological effects induced by ultrasound. the gas-vacuolate cyanobacterium microcystis aeruginosa and the gas-vacuole negative cyanobacterium synechococcus pcc 7942 responded differently to ultrasound. when m. aeruginosa was irradiated by 1.7 mhz ultrasound at 0.6 w cm(-2) every day, it showed a decrease of nearly 65% in biomass increment, and this group's generation ... | 2004 | 15261016 |
| mobile dna elements in the gas vesicle gene cluster of the planktonic cyanobacteria microcystis aeruginosa. | insertion sequences (is) have been characterized in microcystis aeruginosa gas vesicle-deficient mutants. ismae4, a homolog of the cyanobacterial is702, belongs to the is5 family, subgroup isl2. ismae2 and ismae3 display typical is features and express a transposase of the is4 and is1 family, respectively. ismae1 exhibits a more complex genetic structure and harbours a degenerated transposase gene distantly related to is1 elements. hybridizations with is-specific dna probes suggest that transpos ... | 2004 | 15268934 |
| comparison of 17 biotests for detection of cyanobacterial toxicity. | the aim of the present study was to compare the sensitivity of 17 acute bioassays of cyanobacterial toxicity by assessment of crude extracts of three cyanobacterial samples (all dominated by microcystis sp. but substantially differing in microcystin-lr content). toxicity of the fractions prepared by solid-phase extraction (spe) for microcystins was also determined. the most sensitive bioassay was the 24-h test with crustacean thamnocephalus platyurus, which elicited high lethality in the samples ... | 2004 | 15269901 |
| cyanobacterial protease inhibitor microviridin j causes a lethal molting disruption in daphnia pulicaria. | laboratory experiments identified microviridin j as the source of a fatal molting disruption in daphnia species organisms feeding on microcystis cells. the molting disruption was presumably linked to the inhibitory effect of microviridin j on daphnid proteases, suggesting that hundreds of further cyanobacterial protease inhibitors must be considered potentially toxic to zooplankton. | 2004 | 15294849 |
| assimilation and depuration of microcystin-lr by the zebra mussel, dreissena polymorpha. | zebra mussels (dreissena polymorpha) are an important component of the foodweb of shallow lakes in the netherlands, amongst others in lake ijsselmeer, an international important wetland. large numbers of ducks feed on these mussels in autumn and winter. the mussels are filter feeders and are exposed to high densities of cyanobacteria in summer and autumn. mussels and cyanobacteria both thrive in lake ijsselmeer. apparently the mussels are somehow protected against accumulation of harmful quantit ... | 2004 | 15312721 |
| environmental conditions associating microcystins production to microcystis aeruginosa in a reservoir of thailand. | three heptapeptide toxins, microcystin-rr, microcystin-ry and microcystin-lr, which can cause health problems in animals and humans were monitored in bang phra reservoir, thailand using reversed-phase high performance liquid chromatography. the concentrations of the three toxins in the reservoir varied greatly depending on location and time water samples were collected. water quality parameters such as light intensity, temperature, ph, dissolved oxygen, suspended solid, chemical oxygen demand, d ... | 2002 | 15328686 |
| first report of cyanobacterium cylindrospermopsis raciborskii from algerian freshwaters. | this study investigated the first report of the cyanobacterium cylindrospermopsis raciborskii in algerian freshwaters. the morphological characteristics of the two morphotypes observed in lake oubeira (algeria) conformed to those of natural populations of c. raciborskii species described in the literature. the two morphotypes produced only straight trichomes. during the study (february 2000-september 2001), this species occurred as a codominant with microcystis spp., and a peak was observed duri ... | 2004 | 15352271 |
| decomposition of microcystin-lr, microcystin-rr, and microcystin-yr in water samples submitted to in vitro dissolution tests. | the presence of cyanobacterial toxins (microcystins) in waters and food increases the risk of toxicity to animal and human health. these toxins can degrade in the human gastrointestinal tract before they are absorbed. to evaluate this possible degradation, water samples spiked with known concentrations of microcystins mc-lr, mc-rr, and mc-yr, which are the toxins most commonly produced by such toxic cyanobacteria as microcystis aeruginosa, oscillatoria spp., and nostoc spp., were submitted to a ... | 2004 | 15366845 |
| development of multispecies algal bioassays using flow cytometry. | multispecies algal bioassays, suitable for assessing copper toxicity, were developed with three marine (micromonas pusilla, phaeodactylum tricornutum, and heterocapsa niei) and three freshwater (microcystis aeruginosa, pseudokirchneriella subcapitata, and trachelomonas sp.) microalgae. flow cytometry was used to separate and count algal signals based on pigment fluorescence and cell size. species were mixed together on the basis of equivalent surface areas to avoid the confounding effect on toxi ... | 2004 | 15376531 |
| cyanobacterial blooms and the presence of cyanotoxins in small high altitude tropical headwater reservoirs in kenya. | the phytoplankton community in three small (0.065-0.249 km2) reservoirs in the stepped plateau landscape in the kinangop area above the rift valley floor in kenya were studied between 1998 and 2000. approximately 70 species of phytoplankton were identified. the community was dominated by chlorophytes, cyanobacteria and chrysophytes. diatoms were rare. the phytoplankton assemblage was frequently dominated by cyanobacteria in the dry season. the phytoplankton assemblage transformed to a mixture of ... | 2004 | 15384729 |
| accumulation and depuration of microcystins (cyanobacteria hepatotoxins) in tilapia rendalli (cichlidae) under laboratory conditions. | in order to understand accumulation and depuration of microcystins (mcysts) in tilapia rendalli, three experiments with juveniles were done. the experiments simulated the fish diet during a microcystis aeruginosa bloom in three different situations. in the first one each fish received daily, during 15 days, fish food plus toxic cells of m. aeruginosa (20.4 microg mcysts fish(-1) day(-1)). in the following 15 days they were fed without toxic cells. in the second experiment, fish were fed only wit ... | 2004 | 15451603 |
| [a direct uretero-enteroanastomosis: a return to the past?]. | the authors analyse their experience with ureter implantations into a small intestinal retaining reservoir--both direct and antireflux. from 1994 to 2004 orthotopic replacement of the urinary bladder (ub) with an ileal segment was performed in 62 patients (59 males, 3 females) for ub cancer (n = 55), microcystis (posttraumatic, radiation-induced, tuberculous) (n = 7). orthotopic replacement of the ub was made according to vip (vesica ileale padovano) technique with creation of antireflux uretero ... | 2004 | 15457948 |
| comparative analysis of cyanobacterial communities from polluted reservoirs in korea. | cyanobacteria are the dominant phototrophic bacteria in water environments. here, the diversity of cyanobacteria in seven korean reservoir waters where different levels of algal blooms were observed during the summer of 2002, was examined by t-rflp analysis. the number of t-rf bands in the haeiii t-rflp profiles analyzed from those water samples ranged from 20 to 44. of these, cyanobacteria accounted for 6.1 to 27.2% of the total bacteria. the water samples could be clustered into 2 groups accor ... | 2004 | 15459645 |
| enzyme-linked immunosorbent assay detection of microcystins using new monoclonal antibodies. | new monoclonal antibodies (mabs) against the microcystin-leucine-arginine variant (microcystin-lr), a cyclic peptide toxin of the freshwater cyanobacterium microcystis aeruginosa, were prepared from cloned hybridoma cell lines. using these mabs, an enzyme-linked immunosorbent assay (elisa) experiment was made for the detection of cyanobacterial hepatotoxins, microcystins in water sampled in soyang lake, korea. the performance of the elisa test with mabs established in this study was evaluated. t ... | 2004 | 15461385 |
| evidence for recombination in the microcystin synthetase (mcy) genes of toxic cyanobacteria microcystis spp. | recombination has been suggested to be an important factor for the genetic variation of bacterial genes, but few studies have dealt with intragenic recombination between the same or closely related species of cyanobacteria. here we provide strong evidence for recombination in the microcystin synthetase (mcy) gene cluster of the toxic cyanobacteria microcystis spp. this gene cluster contains 10 genes (mcya to j) that encode a mixed polyketide synthase (pks)/nonribosomal peptide synthetase (nrps) ... | 2004 | 15461420 |
| cereulide, the emetic toxin of bacillus cereus, is putatively a product of nonribosomal peptide synthesis. | to determine if cereulide, the emetic toxin produced by bacillus cereus, is produced by a nonribosomal peptide synthetase (nrps). | 2004 | 15479414 |
| distribution of microcystin-producing and non-microcystin-producing microcystis sp. in european freshwater bodies: detection of microcystins and microcystin genes in individual colonies. | microcystis is a well-known cyanobacterial genus frequently producing hepatotoxins named microcystins. toxin production is encoded by microcystin genes (mcy). this study aims (i) to relate the mcy occurrence in individual colonies to the presence of microcystin, (ii) to assess whether morphological characteristics (morphospecies) are related to the occurrence of mcy genes, and (iii) to test whether there are geographical variations in morphospecies specificity and abundance of mcy genes. individ ... | 2004 | 15490561 |
| a method to extract algae toxin of microcystin-lr. | a simple and low-cost method to obtain cyanobacterial toxin microcystin-lr (mc-lr) was developed. a new strain of microcystis aeruginosa, named dc-1, producing microcystin-lr but not microcystin-rr, was separated from the field blooming algae samples of dianchi lake, in southwest of china. following three times' freeze and thaw treatment, the cultivated dc-1 cells were extracted with 40% methanol in water. the extract was centrifuged and the supernatant applied to a hydrophilic-lipophilic balanc ... | 2004 | 15495984 |
| cyanopeptolin 963a, a chymotrypsin inhibitor of microcystis pcc 7806. | a new depsipeptide, cyanopeptolin 963 a (1), was isolated from an axenic strain of the toxic freshwater cyanobacterium microcystis pcc 7806. the structure of this compound was elucidated by chemical and spectroscopic analyses, including high-resolution esi-fticr-ms, 2-d nmr, and gc-ms of the hydrolysate. the major structural difference compared to previously characterized cyanopeptolins of this strain is the replacement of the basic amino acid in position 3 by l-tyrosine. compound 1 displayed in ... | 2004 | 15497957 |
| [phytoplankton community in a recreational fishing lake, brazil]. | the assessment of water quality and phytoplankton community in recreational environments allows to setting management programs aiming at preventing potential harm to human health. the purpose of the present study was to describe phytoplankton seasonal changes in a freshwater system and their relation to water quality. | 2004 | 15499439 |
| factors influencing the spatio-temporal distribution of benthic microcystis aeruginosa colonies (cyanobacteria) in the hypertrophic grangent reservoir (loire, france). | the spatio-temporal distribution of benthic colonies of microcystis aeruginosa in grangent reservoir (france) in 2000 was not homogeneous and appeared to be controlled by many external factors: lake depth, station morphometry, substratum and hydraulic regime (lacustrine or fluvial). a most important concentration of benthic colonies was found at deep sites with fine sediment or at sites where the sediment was rich in organic matter. in spite of a stable water level and a minimum flow during summ ... | 2004 | 15506524 |
| toxic cyanobacteria strains isolated from blooms in the guadiana river (southwestern spain). | this paper describes the occurrence of toxic cyanobacteria along the guadiana river over its course between mérida and badajoz (extremadura, spain). water sampling for phytoplankton quantification and toxin analysis was carried out regularly between 1999 and 2001 in six different locations, including two shallow, slow-flowing river sites, two streamed river sites and two drinking water reservoirs. the cyanobacterial community differed significantly between these locations, especially during the ... | 2004 | 15515966 |
| physiological and biochemical analyses of microcystin-rr toxicity to the cyanobacterium synechococcus elongatus. | freshwater microcystis may form dense blooms in eutrophic lakes. it is known to produce a family of related cyclic hepatopeptides (microcystins, mc) that constitute a threat to aquatic ecosystems. most toxicological studies of microcystins have focused on aquatic animals and plants, with few examining the possible effects of microcystins on phytoplankton. in this study we chose the unicellular synechococcus elongatus (one of the most studied and geographically most widely distributed cyanobacter ... | 2004 | 15526266 |
| inactivation of an abc transporter gene, mcyh, results in loss of microcystin production in the cyanobacterium microcystis aeruginosa pcc 7806. | the cyanobacterium microcystis aeruginosa is widely known for its production of the potent hepatotoxin microcystin. microcystin is synthesized nonribosomally by the thiotemplate function of a large, modular enzyme complex encoded within the 55-kb microcystin synthetase (mcy) gene cluster. also encoded within the mcy gene cluster is a putative atp binding cassette (abc) transporter, mcyh. this study details the bioinformatic and mutational analyses of mcyh and offers functional predictions for th ... | 2004 | 15528494 |
| subchronic oral toxicity of microcystin in common carp (cyprinus carpio l.) exposed to microcystis under laboratory conditions. | the subchronic oral toxicity of microcystin in common carp (cyprinus carpio l.) was investigated in this study. the fish (mean body weight of 322+/-36 g, n=10) were orally exposed to microcystis by feeding with bloom scum at a dose of 50 microg microcystins/kg body weight under laboratory conditions for 28 days. growth assay results showed that microcystin could completely inhibit the growth of carp, but failed to change the fish hepatosomatic index. ultrastructural examination by electron micro ... | 2004 | 15530963 |
| effects of nitrogen forms on the production of cyanobacterial toxin microcystin-ir by an isolated microcystis aeruginosa. | a cyanobacterial strain, which produced high content of microcystin-lr (mc-lr) but no microcystin-rr (mc-rr), was isolated from the hypertrophic dianchi lake in china and identified as microcystis aeruginosa dc-1. effects of nitrogen containing chemicals and trace elements on the growth and the production of mc-lr by this strain were studied. in the presence of bicine, compared with urea and ammonium, nitrate greatly promoted the growth and the production of mc-lr. however, leucine and arginine, ... | 2004 | 15533019 |
| toxicity of microcystin from cyanobacteria growing in a source of drinking water. | microcystin-lr (mc-lr) is a cyanobacterial heptapeptide that presents acute and chronic hazards to animal and human health. the morphological changes in mitochondria are the primary effect induced by mc-lr leading to cell death. we investigated the toxicity of cyanobacterial microcystin-containing extract (cem) on the respiratory complex of mammalian mitochondria from bos taurus. cyanobacterial blooms of microcystis aeruginosa were harvested from sulejow reservoir, a source of drinking water in ... | 2004 | 15556080 |
| development of a universal microarray based on the ligation detection reaction and 16s rrna gene polymorphism to target diversity of cyanobacteria. | the cyanobacteria are photosynthetic prokaryotes of significant ecological and biotechnological interest, since they strongly contribute to primary production and are a rich source of bioactive compounds. in eutrophic fresh and brackish waters, their mass occurrences (water blooms) are often toxic and constitute a high potential risk for human health. therefore, rapid and reliable identification of cyanobacterial species in complex environmental samples is important. here we describe the develop ... | 2004 | 15574913 |
| [hepatotoxicity of the microcystin cyanotoxin]. | at public health, there is increasingly interest on evaluating the possibility of human intoxication by biotoxins from blue-green algae, mainly the hepatotoxins from the microcystin group. microcystin, a monocyclic heptapeptide, is mainly produced by a cyanobacteria called microcistis aeruginosa. it is characterized by a few variable amino acids, from which two of them have an unusual structure and play an important role in the hepatotoxicity of the microcystin. although human illnesses include ... | 2004 | 15586902 |
| a novel rhythm of microcystin biosynthesis is described in the cyanobacterium microcystis panniformis komárek et al. | the presence of microcystins (mcy) in the cyanobacteria microcystis panniformis komárek et al. is reported for the first time. this strain of cyanobacterium has been isolated from barra bonita, an eutrophicated water reservoir in são paulo state, brazil. the identification of m. panniformis was confirmed by both traditional morphological analysis and the phycocyanin intergenic spacer sequences. mcy-lr and [asp(3)]-mcy-lr were identified in this strain after hplc purification and extensive esi-ms ... | 2005 | 15596154 |
| effect of nannochloris sp. on the toxicity of four algae. | the effect of nannochloris sp. on the toxicity of cultures of four algae was evaluated using a microtox 500 that measures the effect on a light-producing bacterium, vibrio fischeri. cultures of four algae produced a toxic effect, but in the presence of nannochloris sp., the effect was reversed, and a stimulatory effect was observed. the effect was tested for microcystis aeroginosa, cyclotella menengheniana, scenedesmus dimorphis, and lyngbya sp. using cultures obtained from the university of tex ... | 2005 | 15663306 |
| laboratory evaluation of six algal species for larval nutritional suitability of the pestiferous midge glyptotendipes paripes (diptera: chironomidae). | glyptotendipes paripes edwards midge larval growth, development, survival, emerging adult size, and food digestibility when provided with six species of algae as food were studied in the laboratory. for the study, eggs from g. paripes adults maintained in the laboratory were reared to the adult stage at 30 degrees c for 60 d on pure culture of each algal species at densities of 0.4, 0.1, and 0.02 mg of algae (fresh weight) per milliliter, as a sole food source. all larvae reared on microcystis s ... | 2004 | 15666740 |
| algal food selection and digestion by larvae of the pestiferous chironomid chironomus crassicaudatus under laboratory conditions. | feeding preference of chironomus crassicaudatus 4th instars when fed on 5 algal species, anabaena flos-aquae, botryococcus braunii, lyngbia cf. aeruginosa, microcystis sp., and scenedesmus quadricauda was studied under laboratory conditions. the various algal species were mixed in pairs at 1:1 ratio (fresh weight) to create 10 possible test combinations. the larvae were allowed to feed individually for 8 h on each algal mixture in tissue culture plates having 4 replicates. four identical algal m ... | 2004 | 15669393 |
| two new chymotrypsin inhibitors isolated from the cyanobacterium microcystis aeruginosa nies-88. | micropeptins 88-n (1) and 88-y (2), new 3-amino-6-hydroxy-2-piperidone (ahp)-containing cyclic depsipeptides, were isolated from microcystis aeruginosa nies-88. the structures were elucidated by analyses of hrfabms, 1d and 2d nmr spectra, and chemical degradation. micropeptins 88-n and 88-y inhibited chymotrypsin. the inhibitory activities were closely related to the amino acid residue that was attached to the amino group of ahp. | 2005 | 15679310 |
| molecular characterization of cyanobacterial diversity in a shallow eutrophic lake. | we have studied the diversity of pelagic cyanobacteria in lake loosdrecht, the netherlands, through recovery and analysis of small subunit ribosomal rna gene sequences from lake samples and cyanobacterial isolates. we used an adapted protocol for specific amplification of cyanobacterial rdna for denaturing gradient gel electrophoresis (dgge) analysis. this protocol enabled direct comparison of cyanobacterial community profiles with overall bacterial profiles. the theoretical amplification specif ... | 2005 | 15683397 |
| characterization of microcystins using in-source collision-induced dissociation. | the efficiency of the in-source collision-induced dissociation (in-source cid) technique for the structural characterization of microcystins (mcysts) was evaluated. microcystins that did not contain arginine underwent facile fragmentation to produce characteristic product ions at relatively low cone voltage and could be fully characterized based on their mass spectra. on the other hand, cyclic peptides possessing arginine residues, such as mcyst-rr, -lr, -yr and nodularin, were considerably more ... | 2005 | 15685685 |
| identification of cyanophage ma-lbp and infection of the cyanobacterium microcystis aeruginosa from an australian subtropical lake by the virus. | viruses can control the structure of bacterial communities in aquatic environments. the aim of this project was to determine if cyanophages (viruses specific to cyanobacteria) could exert a controlling influence on the abundance of the potentially toxic cyanobacterium microcystis aeruginosa (host). m. aeruginosa was isolated, cultured, and characterized from a subtropical monomictic lake-lake baroon, sunshine coast, queensland, australia. the viral communities in the lake were separated from cya ... | 2005 | 15691911 |
| acute skin irritant effects of cyanobacteria (blue-green algae) in healthy volunteers. | to assess the skin irritant potential of a range of laboratory grown cyanobacterial species using skin-patch testing on human volunteers. | 2004 | 15707167 |
| allelopathic effects of the toxic cyanobacterium microcystis aeruginosa on duckweed, lemna gibba l. | cyanotoxins are a group of compounds produced by cyanobacteria that can have severe physiological effects on other organisms, including humans. the potential allelopathic effects of microcystis aeruginosa, a toxic cyanobacterium, on the duckweed plant, lemna gibba l., were examined using three experimental methods: (1) a series of toxicity bioassays, (2) evaluation of toxin production by m. aeruginosa in the direct and indirect presence of l. gibba, and (3) inhibition of oxygen evolution in phot ... | 2005 | 15712290 |
| toxicity of fluoroquinolone antibiotics to aquatic organisms. | toxicity tests were performed with seven fluoroquinolone antibiotics, ciprofloxacin, lomefloxacin, ofloxacin, levofloxacin, clinafloxacin, enrofloxacin, and flumequine, on five aquatic organisms. overall toxicity values ranged from 7.9 to 23,000 microg/l. the cyanobacterium microcystis aeruginosa was the most sensitive organism (5-d growth and reproduction, effective concentrations [ec50s] ranging from 7.9 to 1,960 microg/l and a median of 49 microg/l), followed by duckweed (lemna minor, 7-d rep ... | 2005 | 15720004 |
| leucine aminopeptidase m inhibitors, cyanostatin a and b, isolated from cyanobacterial water blooms in scotland. | two leucine aminopeptidase m inhibitors, cyanostatin a and b, were isolated from cyanobacterial water blooms at loch rescobie in scotland, and specifically from a microcystis species. both inhibitors were lipopeptides containing 3-amino-2-hydroxydecanoic acid and weak inhibitors of protein phosphatase (pp2a). both strongly inhibited the activity of leucine aminopeptidase m with ic50 values of 40 and 12 ng/ml, respectively. | 2005 | 15721946 |
| influence of ultrasonic field on microcystins produced by bloom-forming algae. | under the background of algae removal and growth inhibition by ultrasonic irradiation, the effects of ultrasonic irradiation on removal of microcystis, the concentration variation of microcystins (mc) produced by microcystis in microcystis suspension, and sonochemical degradation of microcystins in water, were studied in the paper. the results showed that ultrasonic irradiation could efficiently inhibit the growth of microcystis, and ultrasonic irradiation shorter than 5 min would not introduce ... | 2005 | 15737547 |
| genetic contributions to the risk assessment of microcystin in the environment. | of the known toxins produced by cyanobacteria, microcystins and nodularins are the most significant threat to human and animal health. knock-out studies have confirmed that microcystins are produced nonribosomally by a multienzyme complex consisting of peptide synthetases, polyketide synthases, and tailoring enzymes. gene clusters for microcystin biosynthesis have been identified and sequenced in the distantly related cyanobacterial genera microcystis, planktothrix, and anabaena. homologous gene ... | 2005 | 15737674 |
| ecotoxicological effects of selected cyanobacterial secondary metabolites: a short review. | cyanobacteria are one of the most diverse groups of gram-negative photosynthetic prokaryotes. many of them are able to produce a wide range of toxic secondary metabolites. these cyanobacterial toxins can be classified in five different groups: hepatotoxins, neurotoxins, cytotoxins, dermatotoxins, and irritant toxins (lipopolysaccharides). cyanobacterial blooms are hazardous due to this production of secondary metabolites and endotoxins, which could be toxic to animals and plants. many of the fre ... | 2005 | 15737675 |
| cyanobacteria and prawn farming in northern new south wales, australia--a case study on cyanobacteria diversity and hepatotoxin bioaccumulation. | harmful cyanobacteria pose a hazard to aquatic ecosystems due to toxins (hepatotoxic microcystins, nodularins, and cylindrospermopsin) they produce. the microcystins and nodularins are potent toxins, which are also tumor promoters. the microcystins and nodularins may accumulate into aquatic organisms and be transferred to higher trophic levels, and eventually affect vector animals and consumers. prawn farming is a rapidly growing industry in australia. because information regarding effects of cy ... | 2005 | 15737678 |
| isolation and purification of the bioactive carotenoid zeaxanthin from the microalga microcystis aeruginosa by high-speed counter-current chromatography. | high-speed counter-current chromatography was successfully applied for the first time to the isolation and purification of the bioactive carotenoid zeaxanthin from the cyanobacterium microcystis aeruginosa. the crude zeaxanthin was obtained by extraction with organic solvents after the microalgal sample had been saponified. preparative high-speed counter-current chromatography with a two-phase solvent system composed of n-hexane-ethyl acetate-ethanol-water (8:2:7:3, v/v/v/v) was successfully per ... | 2005 | 15739885 |
| effects of algicide (copper sulfate) application on short-term fluctuations of phytoplankton in lake paranoá, central brazil. | short-term fluctuations and structure of phytoplankton were examined for two months in the dry season (august-september/1997) in a eutrophic reservoir of central brazil. algicide treatment for the control of microcystis aeruginosa bloom influenced the short-term variation pattern of the phytoplankton community. algicide treatment was effective in controlling m. aeruginosa bloom, but it also influenced the cylindrospermopsis raciborskii population. these species retained low densities, showing sm ... | 2004 | 15744422 |
| [flocculation and removal of water bloom cells microcystis aeruginosa by chitosan-modified clays]. | the kinetics of flocculation and removal of microcystis aeruginosa by chitosan-modified clays was studied. the efficiency of flocculating and removing of algal cells was greatly improved after the modification of the clays. about 80% of algae cell was removed in 0.5 hour, and 90% in 2 hours, when 11 mg/l modified sepiolite was added. algae-removal capacities of different clays were all improved to a similar level of >90% at a total loading of 11 mg/l after being modified with chitosan. the effic ... | 2004 | 15759878 |
| [isolation and activity of bacteria for the biodegradation of microcystins]. | the abilities of bacterial communities, which collected from the sediment and surface water of dianchi lake, for the biodegradation of microcystins (mcs) were firstly investigated. it was shown that the biodegradation rates of both mc-rr and lr by bacteria in sediment were apparently higher than those by bacteria on surface water. five strains of bacteria, which have the abilities in the biodegradation of mcs, from the sediment were isolated using the liquid and solid medium containing mc-rr and ... | 2004 | 15759880 |
| [effect of growth phase on the flocculation of algal cells using clays]. | four different growth phases, late lag phase, middle logarithmic phase, late logarithmic phase and early senescence phase of microcystis aeruginosa 469 were studied for their surface hydrophobicity (xylene-water system) and surface charge (zeta potential), followed by flocculation tests with sepiolite of 0.2 g/l. the results showed that the values of hydrophobicity were 64%, 48%, 58% and 70%, and the algal removal efficiencies after 60 min were 97%, 87%, 81% and 99% respectively, indicating a go ... | 2004 | 15759887 |
| age-dependent effects on biochemical variables and toxicity induced by cyclic peptide toxin microcystin-lr in mice. | microcystins are naturally occurring hepatotoxins produced by certain strains of microcystis aeruginosa and microcystin-lr is the most toxic among the 60 microcystin variants isolated so far. these toxins have been implicated in both human and livestock mortality. in the present study we evaluated the age-dependent hepatotoxic effects of microcystin-lr (mc-lr) in mice after intraperitoneal and oral route of exposure. for acute toxicity studies by intraperitoneal route, 1 ld(50) dose of mc-lr (43 ... | 2005 | 15792618 |
| selective control of toxic microcystis water blooms using lysine and malonic acid: an enclosure experiment. | three enclosures (10 x 10 x 1.5-1.3 m in depth) were set beside dianch lake, kunming, people's republic of china, for the period from july 28 to august 26, 2002. the enclosures were filled with cyanobacterial (microcystis aeruginosa) water bloom-containing lake water. lake sediment that contained macrophytes and water chestnut seeds was spread over the entire bottom of each enclosure. initially, 10 g/m(2) of lysine was sprayed in enclosure b, and 10 g/m(2) each of lysine and malonic acid were sp ... | 2005 | 15793822 |
| the toxicity of microcystin lr in mice following 7 days of inhalation exposure. | microcystins, a family of cyclic heptapeptides produced by the cyanobacteria, microcystis aeruginosa, have documented hepatotoxic and tumor promoting activities. the purpose of this study was to evaluate the toxicity of inhaled microcystin lr (microcystin). male balb/c mice were exposed by nose-only inhalation to 260-265 microg microcystin/m(3) for 7 days. the low-, mid- and high-dose groups were exposed for 0.5, 1, and 2h, respectively. control animals were sham exposed to aerosolized vehicle. ... | 2005 | 15804518 |
| cysteine and serine protease-mediated proteolysis in body homogenate of a zooplankter, moina macrocopa, is inhibited by the toxic cyanobacterium, microcystis aeruginosa pcc7806. | the paper describes the characterization of proteases in the whole body homogenate of moina macrocopa, which can possibly be inhibited by the extracts of microcystis aeruginosa pcc7806. with the use of oligopeptide substrates and specific inhibitors, we detected the activities of trypsin, chymotrypsin, elastase and cysteine protease. cysteine protease, the predominant enzyme behind proteolysis of a natural substrate, casein, was partially purified by gel filtration. the substrate sds-polyacrylam ... | 2005 | 15820132 |
| differential sensitivity of three cyanobacterial and five green algal species to organotins and pyrethroids pesticides. | in this work, five organotins and pyrethroids pesticides were tested to examine their effects on the three cyanobacteria anabaena flos-aquae, microcystis flos-aquae, mirocystis aeruginosa and on the five green algae selenastrum capricornutun, scenedesmus quadricauda, scenedesmus obliqnus, chlorella vulgaris, chlorella pyrenoidosa through 96 h acute toxicity tests. the results indicated that: (1) the decreasing order of the average acute toxicity to cyanobacteria and green algae of five dissimila ... | 2005 | 15833245 |