Nannochloris

Some effort has been directed toward understanding the growth requirements of the alga of interest, allelopathic alga (13), the optimum salinity (14), the distribution of allelopathic agents (15), and the temperature optimum (16). This paper reviews the approaches taken to separate the allelopathic agents from the other materials and the methods used to characterize the biological activity of aponin from Nannochloris sp. 

Isolation of the Crude Extract. An isolation of Nannochloris sp. (previously referred to as Gomphosphaeria aponina) was cultured from... 

Figure 2. HPLC chromatograms (isocratic mode, 60% methanol, 40% water) of sediment extracts from 15 study sites in west Florida coastal waters. Migration profile are compared among sediment extracts and crude extract of Nannochloris sp. cell-free culture [See Moon and co-workers (.26) for specific sites].

The cytolytic agent termed aponin has been characterized in terms of biological activity, and the results to date indicate a material that does not adversely affect the organisms tested. Material isolated from cultures of Nannochloris sp. also has some phytotoxic activity as evidenced by the assays with lettuce seeds, and some antifungal activity. The materials elaborated by Nannochloris sp. thus have environmental significance, but it must be admitted that the full significance of these materials, like others, remains to be fully appreciated. 

Mayasich, J.M., E.P. Karlander, and D.E. Terlizzi, Jr. 1986. Growth responses of Nannochloris oculata Droop and Phaeodactylum tricomutum Bohlin to the herbicide atrazine as influenced by light intensity and temperature. Aquat. Toxicol. 8 175-184. 

Derby, M.L., et al.. Studies of the effect of Psi-APONIN from Nannochloris sp. on the Florida red tide organism Karenia brevis, Toxicon, 41, 2, 245, 2003. 

Perez, E., Sawyers, W. and Martin, D., Identification of allelopathic substances produced by Nannochloris aculata that affects a red tide organism Gymnodinium breve, Biomed. Lett., 56, 7, 1997. 

Perez, E., Sawyers, W.G. and Martin, D.F., Lysis of Gymnodinium breve by cultures of the green alga Nannochloris eucaryotum, Cytobios, 104, 405, 25, 2001. 

Femandez-Casalderrey, A., Ferrando, M.D. and Andreu-Moliner, E. (1993) Chronic toxicity of methylparathion to the rotifer Brachionus calyciflorus fed on Nannochloris oculata and Chlorella pyrenoidosa, Hydrobiologia 255/256, 41-49. 

Lohrenz, S. E., and Taylor, C. D. (1987). Inorganic C as a probe of growth rate dependent variations in intracellular free amino acid and protein composition of NH -limited continuous culmres of Nannochloris atomis Butcher. J. Exp. Mar. Biol. Ecol. 106, 31—55. 

Nedoma et al. (2003) compared values of cell-specific activity (surface phosphomonoesterase activity per cell) obtained in their own study of two waterbodies in the Czech Republic (10-2260 fmol/cell/h, methylumbelliferyl phosphate) with those in the literature. These include (expressed as fmol/cell/h) Phaeocystis, 2.5 (methyl fluorescin phosphate van Boekel and Veld-huis, 1990) Nannochloris, 0.5-5.5 [para-nitrophenyl phosphate Lubifin et al.,... 

Freshwater macroinvertebrates were comparatively sensitive to diazinon. Results of large-scale experimental stream studies showed that dose levels of 0.3 p,g diazinon/L caused a 5-8-fold reduction in emergence of mayflies and caddisflies within 3 weeks after 12 weeks, mayflies, damselflies, caddisflies, and amphipods were absent from benthic samples. Elevated (and catastrophic) drift of stream invertebrates was also documented in diazinon-treated streams, especially for amphipods, leeches, and snails. Short-term tests of 5-h duration with rotifers (Brachionus calyciflorus) show a 50% reduction in feeding rate on alga (Nannochloris oculata) at 14.2 mg/L, with long-term implications to population stability. 

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