<1> Accession Number PREV200000242787 Author/Editor/Inventor Ishii Hiroshi [a]. Abe Toshihiko [a]. Institution [a] School of Marine Science and Technology, Tokai University, Orido 3-20-1, Shimizu, Shizuoka, 424 Japan. Title Release and biodegradation of microcystins in blue-green algae, Microcystis PCC7820. Source Journal of the School of Marine Science & Technology Tokai University. (49). 2000. 143-157. Abstract Microcystis cells synthesize hepatotoxins and frequently become dominant in Japanese fresh water blooms. The toxins termed microcystins are cyclic heptapeptides and expose to risks with death for animals and humans. The decomposition of microcystins which are stable in ordinary condition, in blue-green algae, Microcystis PCC 7820, was investigated under aseptic condition. The release of microcystin-LR, -LY, -LW, and -LF was observed after cell lysis and persisted in culture medium where the microcystin-LR concentration reached 5.5 mg/l. These results indicated that the release of these toxins would not be due to physiological secretion, suggesting that biodegradation of microcystins should occur in natural condition. Microcystins were degraded at eighth day after adding water sample from lake Suwa, but not after adding boiled water sample from Lake Suwa, indicating that microorganism(s) indigenous to Lake Suwa would involve in the degradation process. The decomposition of microcystins was more notable in the presence of bed sediment and mud collected from local sources, in which microcystin-LR, -LY, -LW, and -LF were decomposed completely in nine days. These results suggest that microorganisms in natural surroundings should be potent agents for the removal of microcystins from drinking water for animals and humans. <2> Accession Number PREV199900190934 Author/Editor/Inventor Yamamoto Yoko [a]. Kouchiwa Takanori. Hodoki Yoshikuni. Hotta Kunimoto. Uchida Hideaki. Harada Ken-Ichi. Institution [a] Faculty of Agriculture, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, 214 Japan. Title Distribution and identification of actinomycetes lysing cyanobacteria in a eutrophic lake. Source Journal of Applied Phycology. 10(4). 1998. 391-397. Abstract Among 83 actinomycete strains isolated from lake sediments, about half were found to lyse cyanobacteria. One (S-9 strain), identified as Streptomyces phaeofaciens, grew well on lawns of living cyanobacteria and rapidly lysed the cyanobacterial cells. The amino acid, L-lysine, secreted by this isolate, was found to be one cause of lysis. Scanning electron microscopy of cyanobacterial cells incubated in the presence of L-lysine revealed that L-lysine caused severe damage to the cell wall. <3> Accession Number PREV199900069662 Author/Editor/Inventor Garza D R. Suttle C A [a]. Institution [a] Dep. Earth Ocean Sciences Oceanography, University British Columbia, Vancouver, B.C. V6T 1Z4 Canada. Title The effect of cyanophages on the mortality of Synechococcus spp. and selection for UV resistant viral communities. Source Microbial Ecology. 36(3). Dec., 1998. 281-292. Abstract Viruses that cause lysis of Synechococcus spp. are present throughout the year in the western Gulf of Mexico. The effect of sunlight on loss rates of cyanophage infectivity was determined by incubating natural cyanophage communities and cyanophage isolates (strains S-PWM1 and S-PWM3) in UV-transparent bags at the surface, and at depth, on several occasions throughout the year. Decay rates of infectivity of natural cyanophage communities at the surface, at Port Aransas, Texas, USA, ranged from undetectable to 0.335 h-1, with the highest rates occurring during the summer. During the spring and winter, decay rates of cyanophage isolates and natural cyanophage communities were generally similar, but during summer, decay rates of isolates were as much as twofold higher than the natural communities. In situ incubations at two offshore stations during a bloom of Synechococcus spp. produced decay rates of 0.53 and 0.75 d-1, integrated over the mixed layer and averaged over 24 h. Based on a burst size of 81 viruses produced per lysed cell (measured for natural cyanobacterial communities in the Gulf of Mexico), cyanophages imposed mortality rates of 1 and 8%, respectively, on Synechococcus spp. In contrast, in nearshore incubations in the winter and spring, cyanophages were responsible for removing Accession Number PREV199900069108 Author/Editor/Inventor Pflugmacher Stephan [a]. Wiegand Claudia. Oberemm Axel. Beattie Kenneth A. Krause Eberhard. Codd Geoffrey A. Steinberg Christian E W. Institution [a] Inst. Freshwater Ecol. Inland Fisheries, Mueggelseedamm 256, 12561 Berlin Germany. Title Identification of an enzymatically formed glutathione conjugate of the cyanobacterial hepatotoxin microcystin-LR: The first step of detoxication. Source Biochimica et Biophysica Acta. 1425(3). Nov. 27, 1998. 527-533. Abstract Cyanobacterial toxins have adverse effects on mammals, birds and fish and are being increasingly recognised as a potent stress factor and health hazard factor in aquatic ecosystems. Microcystins, cyclic heptapeptides and a main group of the cyanotoxins are mainly retained within the producer cells during cyanobacterial bloom development. However, these toxins are released into the surrounding medium by senescence and lysis of the blooms. Any toxin present could then come into contact with a wide range of aquatic organisms including phytoplankton grazers, invertebrates, fish and aquatic plants. Recent studies showed the conversion of microcystin in animal liver to a more polar compound in correlation with a depletion of the glutathione pool of the cell. The present study shows the existence of a microcystin-LR glutathione conjugate formed enzymatically via soluble glutathione S-transferase in various aquatic organisms ranging from plants (Ceratophyllum demersum), invertebrates (Dreissena polymorpha, Daphnia magna) up to fish eggs and fish (Danio rerio). The main derived conjugate was characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry yielding a mass of m/z 1302, which is equivalent to the mass assumed for a glutathione microcystin-LR conjugate. This conjugate appears to be the first step in the detoxication of a cyanobacterial toxin in aquatic organisms. <5> Accession Number PREV199900048451 Author/Editor/Inventor Agusti Susana. Satta Maria Paola. Mura Maria Paola. Benavent Esther. Institution Centro de Estudios Avanzados de Blanes, CSIC, Cami de Santa Barbara s/n, 17300 Blanes, Girona, Spain. Title Dissolved esterase activity as a tracer of phytoplankton lysis: Evidence of high phytoplankton lysis rates in the northwestern Mediterranean. Source Limnology & Oceanography. 43(8). Dec., 1998. 1836-1849. Abstract Phytoplankton cell lysis is perceived to be an important loss process in the sea, although a quantification of this process has proved elusive. A recently developed method, based on the measurement of dissolved esterase activity (EA), was used to estimate the release of esterases following phytoplankton cell lysis in an effort to evaluate the importance of this process as a loss factor in the summer phytoplankton of the northwestern Mediterranean Sea. Implicit in this method was the assumption that only the lysis of phytoplankton cells caused these enzymes to be released to the medium. This assumption was tested by analyzing the presence and release of esterases by marine bacteria, heterotrophic flagellates, and heterotrophic ciliates, all isolated from the Blanes Bay (northwestern Mediterranean, Spain), and by phytoplankton grown in culture (Synechococcus elongatus, Dunaliella sp., Chlorella sp., Phaeodactyllum tricomutum, and Chaetoceros decipiens). The dissolved EA found during the growth, stationary, and decay phases of microheterotrophs (bacteria, flagellate, and ciliate) was negligible when compared to that found for phytoplanktonic cultures. Differences in cell volume explained the differences in cell EA among the organisms, but heterotrophs showed lower cell EA (10-50-fold) than phytoplanktonic cells of similar cell size. These results support the assumption that microheterotrophs do not contribute significant amounts of EA to the dissolved pool, allowing the use of the method to estimate phytoplankton lysis. Independent estimates of cell loss in phytoplankton cultures, derived from cell cycle analysis, confirmed the estimates of cell lysis obtained from the measurement of dissolved EA. During the study conducted in the Mediterranean Sea, the water column was strongly stratified, showing a deep (40-55 m) chlorophyll a (Chl a) maximum (DCM; 1.25 +- 0.09 mug liter-1) and low surface Chl a concentrations (0.09 +- 0.008 mug liter-1). Phytoplankton lysis rates ranged between 0.026 d-1 and 1.9 d-1, and they declined significantly with depth; the fastest rates were found in surface waters and the slowest ones at the DCM. Despite the fast gross growth rates of surface phytoplankton (as calculated from phytoplankton biovolume and oxygen production), the calculated lysis rates represented a considerable proportion of gross phytoplankton growth rate (50%) at the surface, whereas they were comparatively less important at the DCM (7%). These results provide strong evidence that phytoplankton lysis can be an important loss factor in the surface waters of this stratified, oligotrophic sea. Phytoplankton lysis could provide the loss factor needed to explain the low phytoplankton biomass despite fast growth and low grazing rates in the northwestern Mediterranean surface waters. The high lysis rate of phytoplankton in surface waters represents an important path by which primary production may fuel the growth of microheterophic organisms, consistent with the high respiration rate of the surface community examined. The conclusion that phytoplankton lysis rates can occur at rates high enough to influence food web dynamics and biogeochemical cycles in the oligotrophic ocean should stimulate research on this largely neglected loss factor in phytoplankton ecology. <6> Accession Number PREV199699037890 Author/Editor/Inventor Vonshak Avigad. Torzillo Giuseppe [a]. Accolla Paola. Tomaselli Luisa. Institution [a] Microalgal Biotechnol. Laboratory, Jacob Blaustein Inst. Desert Res., Ben-Gurion Univ. Negev, Sede-Boker Campus 84990 Israel. Title Light and oxygen stress in Spirulina platensis (cyanobacteria) grown outdoors in tubular reactors. Source Physiologia Plantarum. 97(1). 1996. 175-179. Abstract As the effects of light and oxygen stress in algae on mass culture has not been intensively studied, we investigated them in Spirulina platensis under outdoor conditions in controlled tubular reactors where the respective roles of each stress can be distinguished. It was observed that exposure of this cyanobacterium at two oxygen concentrations (ca 20 and 53 mg l-1) caused very little change in the ratio between variable and maximum fluorescence (F-v/F-m) during the day even when the culture was grown at higher oxygen concentration (about 7% lower in the evening than in the morning). Vice-versa, when the photochemical efficiency of PSII (photon yield PHI-e) was measured, a reduction of about 20% was observed. Neither the F-v/F-m ratio nor the PHI-e of the culture grown at the lower oxygen concentration changed significantly during the day. The daily productivity of the culture exposed to the higher oxygen concentration was reduced by about 20%. Laboratory cultures bubbled with air or pure oxygen under continuous light showed a similar response; i.e., a smaller decrease in F-v/F-m (17%) than in the PHI-e (56%) after 4 h. After 32 h of culture in pure oxygen, a total lysis of the cells occurred. Our results support the hypothesis that photoinhibition and photooxidation, two traditionally linked terms, although often closely associated under similar environmental conditions, may comprise two types of stress with different sites of inhibition. <7> Accession Number PREV199598240987 Author/Editor/Inventor Yamada Naoki [a]. Murakami Nobutoshi. Kawamura Norihisa. Sakakibara Jinsaku. Institution [a] Aichi Prefectural Inst. Public Health, 7-6 Nagare, Tsuji-machi, Kita-ku, Nagoya 462 Japan. Title Mechanism of an Early Lysis by Fatty Acids from Axenic Phormidium tenue (Musty Odor-Producing Cyanobacterium) and Its Growth Prolongation by Bacteria. Source Biological & Pharmaceutical Bulletin. 17(9). 1994. 1277-1281. Abstract We have previously demonstrated that bacteria-containing Phormidium tenue, a cyanobacterium which produces musty odor 2-methylisoborneol, grew beyond 8 weeks, whereas axenic alga perished suddenly between the 3rd week and the 4th week while being cultured in the laboratory. This mechanism was investigated. It is assumed that when algal cells grow beyond a certain level, the supply of CO-2 becomes inadequate and results in the rapid lysis of axenic alga. At that time, inhibitory substances liberated from algal cells kill the surviving alga. Since the process occurs continuously, this alga is finally annihilated. On the other hand, since inhibitory substances are metabolized or degraded by bacteria coexistent with alga, bacteria-containing P. tenue maintains growth for a long time. The growth-inhibitory substance was found to be unsaturated free fatty acids. <8> Accession Number PREV199598090041 Author/Editor/Inventor Haney James F [a]. Forsyth Don J. James Mark R. Institution [a] Dep. Zool., Univ. New Hampshire, Durham, NH 03824-3544 USA. Title Inhibition of zooplankton filtering rates by dissolved inhibitors produced by naturally occurring cyanobacteria. Source Archiv Fuer Hydrobiologie. 132(1). 1994. 1-13. Abstract We examined the inhibitory effects of lake populations of cyanobacteria on the feeding activities of zooplankton. Filtering rates of Daphnia carinata, Ceriodaphnia dubia and Boeckella propinqua were measured in filtrate of Anabaena minutissima var. attenuata, Anabaena flos-aquae and Microcystis aeruginosa that had been collected in the field and incubated for 20 hours and filtered through a GF/C glass-fiber filter. Anabaena and Microcystis released dissolved products into the water that reduced the filtering rates of Daphnia and Ceriodaphnia by 50% or more. Boeckella filtering rates were not significantly lower in the filtrates, indicating this grazer is less sensitive to the inhibitor released by the cyanobacteria. The effect of the cyanobacteria inhibitor was independent of the concentration of food (Cyclotella) and size of the Daphnia. The feeding inhibitors measured in this study appear to be fast acting and are probably metabolic products released into the water during periods of active growth of the cyanobacteria, rather than slow acting, endotoxins released as cells lyse. <9> Accession Number PREV199497333095 Author/Editor/Inventor Sallal A-K J. Nimer N A. El-Durini N M. Institution Dep. Biol. Sci., Fac. Sci., Univ. Sci. and Technol., Irbid, Jordan. Title Effect of gibberellic acid on photosynthetic electron transport reactions and nitrogenase activity in Anabaena cylindrica. Source Microbios. 78(314). 1994. 17-25. Abstract Various concentrations of gibberellic acid (GA) were tested for their effects on photosynthetic reactions and dinitrogen-fixation (acetylene reduction) in Anabaena cylindrica. The optimum concentration of GA for growth and oxygen evolution was 10-4 M, and NADP photoreduction was also enhanced. A pronounced effect was evident on the photosystem II-Hill reaction, while the effect on the photosystem I-Mehler reaction was much less. A concentration of 10-6 M GA exerted some inhibition on growth and photosynthetic reactions, while 10-2 and 10-3 M concentrations led to complete lysis. The optimum concentration of GA for maximum nitrogenase activity was 10-5 M, which also increased heterocyst differentiation. <10> Accession Number PREV199497180541 Author/Editor/Inventor Sallal A-K J. Institution Dep. Biol. Sci., Fac. Sci., Univ. Sci and Technol., Irbid, Jordan. Title Lysis of cyanobacteria with Flexibacter spp isolated from domestic sewage. Source Microbios. 77(310). 1994. 57-67. Abstract Five species of filamentous cyanobacteria and two species of Flexibacter were isolated from domestic sewage. Cells and filtrates of F. flexilis and F. sancti lysed the cyanobacterium Oscillatoria williamsii. Inhibition of the photosynthetic electron transport reactions, and glycolate dehydrogenase and nitrogenase activity of O. williamsii due to its incubation with F. flexilis, were observed. Scanning electron micrographs revealed the attachment of F. flexilis to the sheaths of O. williamsii which resulted in the excretion of lysozyme and lysis of the cyanobacterium. Seasonal variations of Flexibacter spp showed that they were more abundant in the aeration tanks during June compared with sewage effluents. <11> Accession Number PREV199497138606 Author/Editor/Inventor Mitsutani Atsushi. Takesue Kaoru. Institution Lab. Fishery Environmental Sci., Dep. Biol. Aquaculture, Shimonoseki Univ. Fisheries, Japan. Title Purification of properties of a protease from a cyanobacteria-lytic bacterium Lysobacter sp. LB-1. [Japanese] Source Journal of Shimonoseki University of Fisheries. 41(2). 1993. 65-75. Abstract A protease from the culture medium of a cyanobacteria-lytic bacterium, Lysobacter sp. strain LB-1, was purified by ammonium sulfate precipitation, anion-exchange chromatography, cation-exchange chromatography (first), hydrophobic chromatography, cation-exchange chromatography (second), and gel filtration in order. The protease was purified 36-fold, and the final yield of it was 4.0%. A molecular weight of the purified enzyme (LB-1 protease A) was estimated as 32,000 from the elution volume at gel filtration. Optimum temperature and pH of the enzyme were 50 apprx 60 degree C and 10 apprx 11, respectively. The enzyme was strongly inhibited by phenylmethylsulfonyl fluoride (PMSF) and weakly inhibited by antipain, but not inhibited by ethylenediamine-tetraacetic acid (EDTA), pepstatin, leupeptin, and phosphoramidon. The enzyme was considered to be concerned in the lysis of cyanobacterial cell by the bacterium, because it could lyse the cell of a cyanobacteria, Anabaena cylindrica treated in sodium dodecyl sulfate solution at 100 degree C. <12> Accession Number PREV199497050479 Author/Editor/Inventor Yamamoto Yoko [a]. Niizumi Seiichi. Urodo Nobuo. Sakamoto Mitsuru. Institution [a] Fac. Agric. Meiji Univ., Higashimita, Kawasaki, 214 Japan. Title Occurrence of heterotrophic bacteria causing lysis of cyanobacteria in a eutrophic lake. Source Japanese Journal of Phycology. 41(3). 1993. 215-220. Abstract 192 strains of heterotrophic bacteria were isolated from the eutrophic Lake Suwa and examined for their ability to lyse cyanobacteria. Approximately 40% of the strains were able to lyse at least one strain of cyanobacteria. The ratio of cyanobacteria-lytic to total isolates in each month was highest in September, when Microcystis blooms began to disintegrate. The genera Alcaligenes, Flavobacterium/Cytophaga group and Pseudomonas accounted for the great majority of strains capable of lysing cyanobacteria. <13> Accession Number PREV199396080888 Author/Editor/Inventor Sugiura Norio [a]. Oyamada Noritaka. Kurosawa Atsuhiko. Saito Tadao. Institution [a] Water Quality Examination Lab., Ibaraki Prefectural Waterworks Bureau, 2972 Ooiwada, Tsuchiura 300 Japan. Title Lytic characteristics of blue-green alga, Microcystis aeruginosa by Pseudomonas sp. Source Japanese Journal of Toxicology & Environmental Health. 39(2). 1993. 94-99. Abstract Lytic characteristics of the blue-green alga, Microcystis aeruginosa by Pseudomonas sp., a strain isolated from the biofilm in a biological treatment facility, were examined in a batch culture experiment. The viable cells of M. aeruginosa were perfectly lysed by the agent for 5 d at 30 degree C in the dark. Optimum conditions for the lysis of M. aeruginosa were 35 degree C and pH 7.0. Several important parameters for the estimation of eutrophicated waters, chlorophyll a, turbidity and COD originating from M. aeruginosa were effectively reduced and their removal were 70%, 84% and 41%, respectively, under the condition of 5 d cultivation at 30 degree C. It was found that M. aeruginosa was efficiently lysed by the agent during a short time. <14> Accession Number 094109281 Authors Henning K. Meyer H. Kraatz Wadsack G. Cremer J. Institution INST. MIKROBIOLOGIE, SANITAETSAKADEMIE DER BUNDESWEHR, NEUHERBERGSTR. 11, W-8000 MUENCHEN 45, GERMANY. Title DETECTION OF A CYTOTOXIC SUBSTANCE PRODUCED BY THE CYANOBACTERIUM MICROCYSTIS-AERUGINOSA STRAIN PCC7806 ISOLATION AND DIFFERENTIATION FROM THE PEPTIDE TOXIN MICROCYSTIN-LR BY CYTOTOXICITY ASSAYS. Source Current Microbiology 25 (3). 1992. 129-134. Abstract Exposure of four permanent cell lines to crude aqueous extracts of the cyanobacterium Microcystis aeruginosa (strain PCC 7806) resulted in rounding and lysis of the cells within a few minutes. Cell damage was quantified by determination of lactate dehydrogenase (LDH) activity in the cell culture supernatants. By gel filtration, cation exchange chromatography and SDS-PAGE, the cytotoxic effects could be related to a defined substance with an apparent molecular weight of about 35 kDa, which was not heat resistant. The physicochemical properties very clearly mark off this compound from the peptide toxin microcystin-LR, which did not show any detectable cytotoxic effects.