TI: Title Growth and grazing of a large heterotrophic dinoflagellate, Noctiluca scintillans, in laboratory cultures AU: Author Nakamura, Yasuo AF: Author Affiliation National Institute for Environmental Studies, Tsukuba, Ibaraki 305-0053, Japan SO: Source Journal of Plankton Research [J. Plankton Res.], vol. 20, no. 9, pp. 1711-1720, Sep 1998 IS: ISSN 0142-7873 AB: Abstract Carbon (C) and nitrogen (N) content and growth/grazing characteristics of the heterotrophic dinoflagellate Noctiluca scintillans were examined in laboratory cultures at 24 degree C. The C and N contents of N. scintillans per unit cell volume were 2.3 x 10 super(-3) pg C mu m super(-3) and 4.1 x 10 super(-4) pg N mu m super(-3), respectively. These values are almost two orders of magnitude lower than those reported for other protozoans such as ciliates and 'typical' heterotrophic dinoflagellates due to an extensive vacuole in the cell of N. scintillans. Among five autotrophic flagellates used as prey, species with an equivalent spherical diameter (ESD) of >10 mu m served as good prey for N. scintillans, but species with an ESD of <5 mu m did not support growth. Growth rates of N. scintillans fed Chattonella antiqua (ESD = 27 mu m; Raphidophyceae) or Ileterosigma akashiwo (ESD = 11 mu m; Raphidophyceae) increased linearly with prey C concentration (PC), with lower growth thresholds of similar to 100 mu g C l super(-1). Grazing rates of N. scintillans fed C. antiqua or H. akashiwo increased linearly with PC without an obvious threshold. Carbon budget calculations for grazing and growth indicated that N. scintillans converts 'excess' C (= total prey C ingested - C necessary for the maintenance of basic metabolic activities) to body C with efficiencies of 0.31 and 0.17 for C. antiqua and H. akashiwo, respectively. TI: Title Growth and grazing of a heterotrophic dinoflagellate, Gyrodinium dominans , feeding on a red tide flagellate, Chattonella antiqua . AU: Author Nakamura, Y; Yamazaki, Y; Hiromi, J AF: Author Affiliation Natl. Inst. Environ. Stud., Tsukuba, Ibaraki 305, Japan SO: Source Marine ecology progress series. Oldendorf [MAR. ECOL. PROG. SER.], vol. 82, no. 3, pp. 275-279, 1992 IS: ISSN 0171-8630 AB: Abstract Growth and grazing of a heterotrophic dinoflagellate, Gyrodinium dominans , were examined in laboratory batch cultures. When Chattonella antiqua was used as prey, G. dominans grew at a rate of ca 0.9/d (at 25 degree C). Cell division of G. dominans was not affected by the light:dark period. Growth rate of G. dominans was significantly affected by temperature and was maximal within the range 25 to greater than or equal to 27.5 degree C. Rate of ingestion of C. antiqua (at ca 1 x 10 super(3) to 2 x 10 super(3) cells/ml) by G. dominans) was 3.8 prey/cell/d and growth efficiencies on the basis of carbon and nitrogen were 0.31 and 0.33, respectively. Results suggest the ecological importance of G. dominans in the disappearance of C. antiqua red tides. TI: Title Impact of copepod grazing on the red-tide flagellate Chattonella antigua . AU: Author Uye, S AF: Author Affiliation Hiroshima Univ., Fac. Appl. Biol. Sci., Fukuyama 720, Japan SO: Source Marine biology. Berlin, Heidelberg [MAR. BIOL.], vol. 92, no. 1, pp. 35-43, 1986 IS: ISSN 0025-3162 NT: Notes Incl. 40 ref. AB: Abstract In the present study, the grazing of adult females of several copepod species is examined using three food types: viz, natural suspended particles, natural suspended particles mixed with cultured Chattonella antigua , and cultured C. antigua . The functional response on C. antigua was investigated for five species of copepods (Acartia erythraea, Calanus sinicus, Centropages yamadai, Paracalanus parvus and Pseudodiaptomus marinus ). Ingestion rates increased linearly with increasing cell concentrations until a maximum level was reached, beyond which the rates were constant. The daily removal rate was 3.4 to 30.8% (mean: 12.3%) of C. antigua biomass at 20 cell ml super(-1) and decreased to 0.6-4.3% (mean: 1.8%) at 500 cells ml super(-1). Therefore, the grazing pressure by the copepod community is important at the initial stage of the red tide. TI: Title Feeding interactions between planktonic copepods and red-tide flagellates from Japanese coastal waters. AU: Author Uye, S; Takamatsu, K AF: Author Affiliation Fac. Appl. Biol. Sci., Hiroshima Univ., Saijo-cho, Higashi-Hiroshima 724, Japan SO: Source Marine ecology progress series. Oldendorf [MAR. ECOL. (PROG. SER.).], vol. 59, no. 1-2, pp. 97-107, 1990 IS: ISSN 0171-8630 NT: Notes 51 ref. AB: Abstract Feeding interactions between inshore marine copepods Pseudodiaptomus marinus and Acartia omorii , and 15 red-tide flagellates were studied by examining egestion rate, mortality and egg production rate of the copepods offered a suspension of each phytoplankton species. Among several species of poor quality as food, Olisthodiscus luteus (Raphidophyceae) was nearly completely rejected by P. marinus , and Gymnodinium nagasakiense (Dinophyceae), Heterosiqma akashiwo (Raphidophyceae, Nagasaki University strain), Chattonella marina (Raphidophyceae) and Fibrocapsa japonica (Raphidophyceae) were almost entirely rejected by A. omorii . Since these flagellates are of preferred cell size and have no hard undigestible cell walls, the rejective feeding by copepods was suspected to be chemically mediated. Effects of chemical stimuli from O. luteus (to P. marinus ) and G. nagasakiense (to A. omorii ) were examined in detail by conducting comparative feeding experiments in a suspension of Heterocapsa triquetra (Dinophyceae), a normally edible species. TI: Title Feeding of a marine copepod Acartia clausi on cultured red-tide phytoplankton. AU: Author Tsuda, A; Nemoto, T AF: Author Affiliation Ocean Res. Inst., Univ. Tokyo 1-15-1, Minamidai, Nakano-ku, Tokyo 164, Japan SO: Source Bulletin of the Plankton Society of Japan. Hiroshima [BULL. PLANKTON SOC. JAPAN.], vol. 31, no. 1, pp. 79-80, 1984 IS: ISSN 0387-8961 AB: Abstract Two series of experiments were conducted to examine the feeding of A. clausi , one of the dominant copepods in Japanese coastal waters, upon the cultured red-tide phytoplankton, Prorocentrum minimum and Chattonella sp. (Kagoshima type). Experiments were carried out on February 11, 1983 in the laboratory (Experiment A) and February 21, 1983 on board the R.V. Tansei-maru (Experiment B). Copepods were collected by vertical hauls of a small conical net or a NORPAC net (95 mu m mesh opening), and surface water was also taken in Tokyo Bay. Cell diameters of P. minimum and Chattonella sp. ranged from 10 to 16 mu m and 25 to 40 mu m, respectively. In both experiments,the ingestion rates of A. clausi were higher at size range with higher concentration and the filtering rates tended to increase with increasing particle size, especially above 30 mu m. At the peaks of the size distribution, A. clausi showed high filtering rates compared with neighboring size ranges of lower concentration. TI: Title AU: AF: SO: IS: AB: Chemical and physical treatments for destruction of phytoflagellate cysts Author Montani, S; Meksumpun, S; Ichimi, K Author Affiliation Dep. Bioresour. Sci., Kagawa Univ., Miki, Kagawa 761-07, Japan Source Journal of Marine Biotechnology [J. Mar. Biotechnol.], vol. 2, no. 4, pp. 179-181, 1995 ISSN 0941-2905 Abstract A big problem with serious impact on the environment and public health is the global spreading of toxic marine dinoflagellates and other nuisance organisms via the discharge of ships' ballast water and sediment. To reduce the dispersal of these organisms, ships' ballast water and sediment containing motile cells and resting cysts should be sterilized before discharge. This study focuses on the ability of some chemical and physical treatments to stop the germination of phytoflagellate cysts under laboratory conditions. The cysts of Chattonella spp. did not germinate after exposure to sodium azide at 500 mg/liter for 48 h. Germination of the cysts of Alexandrum spp. and Gymnodinium spp. decreased to about 10% of the controls after exposure to 500 mg/liter of sodium azide. Germination of phytoflagellate cysts did not occur after exposure to hydrogen peroxide at 150 mg/liter for 48 h. After exposure to ultraviolet light for 2 h, the germination of Chattonella spp. cysts decreased to 6% of the control, whereas germination of cysts of other species of phytoflagellates was more than 40% of the controls. No phytoflagellates cysts germinated after exposure to 45 degree C for 3 min or after exposure to electric shock for 5 s. Because the electric shock method is effective and economical, it may be applicable to ships' ballast water if a procedure can be developed. TI: Title Photocontrol of nuclear DNA replication in Chattonella antiqua (Raphidophyceae). AU: Author Nemoto, Y; Kuroiwa, T; Furuya, M AF: Author Affiliation Dep. Biol., Fac. Sci., Univ. Tokyo, Hongo, Tokyo 113, Japan SO: Source Plant & Cell Physiology [PLANT CELL PHYSIOL.], vol. 28, no. 6, pp. 1043-1049, 1987 IS: ISSN 0032-0781 AB: Abstract The timing of nuclear DNA replication was examined in a synchronized cell population of a red-tide flagellate, Chattonella antiqua , using fluorescence microspectrophotometry with a DNA-specific fluorochrome, 4',6-diamidino-2phenylindole (DAPI). The conclusion reached was that light irradiation is necessary for nuclear DNA replication in C. antiqua and that the timing of the replication is dependent upon only the timing of the onset of the last irradiation. In other words, a light-on signal induces the transition of cell nuclei from the G sub(1) into the S phase and also determines the timing of this event. When not irradiated, cells are arrested in the G sub(1) phase. TI: Title Inductive and inhibitory effects of light on cell division in Chattonella antiqua . AU: Author Nemoto, Y; Furuya, M AF: Author Affiliation Dep. Biol., Fac. Sci., Univ. Tokyo, Hongo, Tokyo 113, Japan SO: Source Plant & Cell Physiology [PLANT CELL PHYSIOL.], vol. 26, no. 4, pp. 669-674, 1985 IS: ISSN 0032-0781 AB: Abstract The cell division of a red tide flagellate, C. antiqua , was synchronously induced under light and dark regimes. It can be concluded that light has both inductive and inhibitory effects on cell division in this alga, the latter effect depending upon the previously given light and dark regimes. TI: Title Buoyancy and phototaxis of Chattonella antiqua (Hada) Ono. AU: Author Yoshida, Y; Kawaguchi, K AF: Author Affiliation Grad. Sch. Agric., Kyoto Univ., Sakyoku, Kyoto, 606, Japan SO: Source Bulletin of the Plankton Society of Japan. Hiroshima [BULL. PLANKTON SOC. JAPAN.], vol. 30, no. 1, pp. 11-19, 1983 IS: ISSN 0387-8961 AB: Abstract Chattonella antiqua (Hada) Ono is one of a red tide algae which did severe damage to the farm fish in the eastern part of Seto Inland Sea in Japan. As a part of the biochemical and ecological studies of C. antiqua , its buoyancy and phototaxis in axenic or unaxenic unialgal culture which related to the diurnal vertical migration were examined. The growth rates of C. antiqua were found to be high in unialgal culture and modified ASP sub(7), culture, compared with those of axenic culture and modified ES culture. The positive buoyancy of C. antiqua) was found in low light intensity or dark condition in 10 days culture, whereas it was scarcely found in 40 days culture. The positive or negative phototaxis of C. antiqua showed a tendency to be stronger as decrease of culture age and increase of intensity of illumination in unialgal culture, whereas it was scarcely found in axenic culture. TI: Title Generation of reactive oxygen species by raphidophycean phytoplankton AU: Author Oda, T; Nakamura, A; Shikayama, M; Kawano, I; Ishimatsu, A; Muramatsu, T AF: Author Affiliation Div. Biochem., Fac. Fish., Nagasaki Univ., Nagasaki 852, Japan SO: Source Bioscience, Biotechnology, and Biochemistry [Biosci., Biotechnol., Biochem.], vol. 61, no. 10, pp. 1658-1662, Oct 1997 IS: ISSN 0916-8451 AB: Abstract Chattonella marina, a raphidophycean flagellate, is one of the most toxic red tide phytoplankton and causes severe damage to fish farming. Recent studies demonstrated that Chattonella sp. generates superoxide (O sub(2) super(-)), hydrogen peroxide (H sub(2)O sub(2)), and hydroxyl radicals ( times OH), which may be responsible for the toxicity of C. marina. In this study, we found that other raphidophycean flagellates such as Heterosigma akashiwo, Olisthodiscus luteus, and Fibrocapsa japonica also produce O sub(2) super(-) and H sub(2)O sub(2) under normal growth condition. Among the flagellate species tested, Chattonella has the highest rates of production of O sub(2) super(-) and H sub(2)O sub(2) as compared on the basis of cell number. This seems to be partly due to differences in their cell sizes, since Chattonella is larger than other flagellate species. The generation of O sub(2) super(-) by these flagellate species was also confirmed by a chemiluminescence assay by using 2-methyl-6-(p-methoxyphenyl)-3,7dihydroimidazo[1,2-a]pyrazin-3-on e (MCLA). All these raphidophycean flagellates inhibited the proliferation of a marine bacterium, Vibrio alginolyticus, in a flagellates/bacteria co-culture system, and their toxic effects were suppressed by the addition of superoxide dismutase (SOD) or catalase. Our results suggest that the generation of reactive oxygen species is a common feature of raphidophycean flagellates. TI: Title Hydroxyl radical generation by red tide algae. AU: Author Oda, T; Akaiki, T; Sato, K; Ishimatsu, A; Takeshita, S; Muramatsu, T; Maeda, H AF: Author Affiliation Dep. Microbiol., Kumamoto Univ. Med. Sci., Kumamoto 860, Japan SO: Source Archives of Biochemistry and Biophysics [ARCH. BIOCHEM. BIOPHYS.], vol. 294, no. 1, pp. 38-43, 1992 IS: ISSN 0003-9861 AB: Abstract The unicellular marine phytoplankton Chattonella marina is known to have toxic effects against various living marine organisms, especially fishes. However, details of the mechanism of the toxicity of this plankton remain obscure. Here we demonstrate the generation of superoxide and hydroxyl radicals from a red tide unicellular organism, C. marina by using ESR spectroscopy with the spin traps 5,5dimethyl-1-pyrroline-N-oxide (DMPO) and N-t-butyl- alpha -phenylnitrone (PBN), and by using the luminol-enhanced chemiluminescence response. The generation of oxygen radical is suggested to be a pathogenic principle in the toxication of red tide to susceptible aquaculture fishes and may be directly correlated with the coastal pollution by red tide.