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Seventeen clones of the toxic, epiphytic-benthic dinofla-gellate Prorocentrum lima (Ehrenberg) Dodge isolated from three separate sites on the reef flats of Heron Island, Australia, were acclimated under the same set of environmental conditions. Morphological features examined for each clone included cell surface configuration, size, and dry weight. Physiological and biochemical features determined for each clone included reproduction rates, pigments (chloropyll a, chlorophyll c[sub2] peridinin, and other xanthophylls) toxins (okadaic acid and methyl-okadaic acid), and macromolecular compounds (total protein, lipid, and carbohydrate). Variation in morphological features and reproduction rates of clones within and between sites was minimal and not significant. Also, variation in biochemical features within an individual site was low, but pronounced differences existed among sites, the most notable of which was toxin content (okadaic acid and methyl-okadaic acid). The greatest difference in biochemical features was between clones isolated from the southern site and clones isolated from the northern and southeastern sites. Results of a cluster analysis of clonal characters support the view that these two groups represent distinct genotypes. We suggest that these groups originated from separate seed sources and that the genetic integrity of each is maintained through asexual reproduction. [ABSTRACT FROM AUTHOR]

Seventeen clones of the ciguatera-causing dinoflagellate Gambierdiscus toxicus Adachi and Fukuyo were to the same environments over several months. Signifacant variance environments over detected between non-acclimated and acclimated cultures for cell potencies, yields and reproduction rates. The resultant variance in acclimated potencies, yields and reproduction rates. The resultant variance in acclimated potencies among clones was statistically significant (P < 0.0001), indicating that potency can be used for a clone of G. toxicus in the acclimated vs. non-acclimated phases can exceed genetic differences between clones. This stresses the need for a rigorous acclimation process. Caribbean isolates of G. toxius were inherently more toxic than isolates from the other areas. One Caribbean clone yielded 55 × 10[sup-4] mu (mouse units)· cells[sup-1] where clones from Bermuda, the Bahamas, and Florida ranged from only 1.8 × 10[sup-4] Mu cell[sup-1] to a maximum of 19.8 × 10[sup-4] mu· cell[sup-1]. Toxicity decreased with increasing latitude (r = 0.819, P < 0.01), indicating that environmental differences probably influenced the potencies, A comparison of acclimated reproduction rates at four light intensities also indicated that genetic differences among clones existed. The resulting reproduction rate/light slopes overlapped, indicating that the clones may be adapted to specific light regimes. [ABSTRACT FROM AUTHOR]

Total protein was determined for cells of Aphanothece halophytica Fremy harvested during early log, mid-log and linear growth phases in media containing 1, 2, and 3 M NaCl. Cells grown in medium containing 1 M NaCl showed a progressive increase in protein content up to a maximum of 76% of dry weight (linear phase). Total protein also increased in cells grown in 3 M Nacl medium showed a progressive decrease in total protein (59.9-43%). Although amounts of protein varied, the percentages of the respective amino acids of hydrolyzed bulk protein were consistent to with 1% for linear phase cells grown in 1, 2, and 3 M NaCl cultures. Percentages of acidic amino acids were 2.3-2.6 times greater than those of the basic amino acids. The amino acid composition of phycocyanin was similar to that of bulk protein. Free amino acids varied with both age of the culture and the concentration of NaCl. The high quantity and quality of the protein observed suggest that A. halophytica might be a useful food organism. [ABSTRACT FROM AUTHOR]

Ocean surgeons Acanthurus bahianus and doctorfish A. chirurgus displayed no preference between food items containing toxic dinoflagellates associated with ciguatera poisoning and nontoxic food when given a choice for up to 42 consecutive days. Two clones of laboratorycultured dinoflagellates Gambierdiscus toxicus and one clone of Prorocentrum concavum were used in separate trials. Gambierdiscus toxicus clone SIU-350 was toxic to both fish species after 5-8 d at a daily ration of 2.5 mg of cells per food item. Clinical signs were similar to those previously reported for blueheads Thalassoma bifasciatum fed the same clone, Clinical signs became less pronounced with time, but recurred with equal intensity when the ration was doubled. No difference in food consumption between toxic and nontoxic food types was observed. Fish fed G. toxicus SIU-175, previously shown to be considerably more toxic to mice Mus sp. and brine shrimp Artemia sp. than to G. toxicus SIU-350, remained asymptomatic at daily rations as high as 7.5 mg of cells per food item. No signs of toxicity were observed in adult brine shrimp that consumed ground muscle and liver tissue from fish fed either G. toxicus clone, indicating that ciguatoxicity had not been induced. Results suggest that herbivorous fish may acclimate to, rather than avoid, macroalgae harboring epiphytic toxic dinoflagellates. Attempts to directly relate these findings to nature should be made cautiously because differences in toxic properties between cultured and wild dinoflagellate cells cannot be discounted. [ABSTRACT FROM AUTHOR]

Four species of piscivorous fishes (coney Epinephelus fulvus; schoolmaster Lutjanus apodus; mahogany snapper L. mahogoni; and largemouth bass Micropterus salmoides) displayed distinct behavioral abnormalities after consumption of a ciguatoxic great barracuda Sphyraena barracuda. Samples of the great barracuda were fed to experimental fishes as ether-soluble extracts or as ground flesh. Largemouth bass were also fed freeze-dried cells of the dinoflagellate Gambierdiscus toxicus in a separate experiment and displayed a similar response, Signs of intoxication included skin color variations, inactivity, loss of equilibrium, erratic swimming, jerky feeding movements, and loss of orientation - and death, in the case of largemouth bass fed 1.0 g or more of great barracuda flesh or 7.1 mgṡg-1 or more of great barracuda extract. These abnormalities usually were observed within 24 h after the feeding of toxic materials, and were apparent in some cases for as long as 76 d. [ABSTRACT FROM AUTHOR]

Distinct behavioral abnormalities were displayed by blueheads Thalassoma bifasciatum (wrasse: Labridae) after consumption of a dinoflagellate responsible for producing ciguatera toxins. The symptoms, including skin color variations, inactivity, loss of equilibrium, erratic swimming, jerky feeding movements, loss of orientation, and loss of net avoidance ability, appeared after oral treatments ranging from 0.26 to 4.88 mg˙g-1 of freeze-dried Gambierdiscus toxicus cells. Results suggest that the adverse effects of toxins on blueheads would increase their susceptibility to predation, subsequently increasing the rate of transference within the food chain. [ABSTRACT FROM AUTHOR]

A new species of Nitella belonging to the N. flexilis species group is described. The new species shows definite relationship to N. flexilis, N. opaca, N. missouriensis, and N. mirabilis. Relationships of the new species to N. acuminata are also discussed. [ABSTRACT FROM AUTHOR]