OBJECTIVEImpact of the presence of bacteria associated with a marine dinoflagellate, Alexandrium tamarense CI01, on the growth and toxin production of the algae in batch culture was investigated.

METHODSPronounced changes in the activities of the algal culture were observed when the culture was treated with different doses of a mixture of penicillin and streptomycin.

RESULTSIn the presence of antibiotics at the initial concentration of 100 u/mL in culture medium, both algal growth and toxin yield increased markedly. When the concentration of antibiotics was increased to 500 u/mL, the microalgal growth was inhibited, but resumed in a few days to eventually reach the same level of growth and toxin production as at the lower dose of the antibiotics. When the antibiotics were present at a concentration of 1 000 u/mL, the algal growth was inhibited permanently.

CONCLUSIONSThe results indicate that antibiotics can enhance algal growth and toxin production not only through their inhibition of the growth and hence competition for nutrients, but also through their effects on the physiology of the algae.

Animals ; Anti-Bacterial Agents ; pharmacology ; Bacteria ; Dinoflagellida ; microbiology ; pathogenicity ; Eutrophication ; Marine Toxins ; biosynthesis ; Penicillins ; pharmacology ; Saxitoxin ; Streptomycin ; pharmacology

Paralytic shellfish poisoning results from consumption of mollusks that have fed on dinoflagellates capable of producing neurotoxins such as saxitoxin. The saxitoxin is concentrated in the shellfish and acts by decreasing sodium-channel permeability, thereby blocking neuronal transmission in skeletal muscles. Symptoms including paresthesia, perioral numbness, perioral tingling, nausea, vomiting, extremity numbness, extremity tingling, dizziness, ataxia, dysphagia, and weakness have been reported. In serious cases, respiratory hold may occur up to 6~24 hours after ingestion. Generally, the treatment for paralytic shellfish poisoning is supportive care, but mechanical ventilation is needed in serious cases acompanied by respiratory hold. We experienced two cases of paralytic shellfish poisoning. Respiratory hold was presented in one case and only mild paresthesia in the other case. After supportive management, including mechanical ventilation in former case, both patients were discharged without sequalae.
Ataxia ; Deglutition Disorders ; Dinoflagellida ; Dizziness ; Eating ; Extremities ; Humans ; Hypesthesia ; Mollusca ; Muscle, Skeletal ; Nausea ; Neurons ; Neurotoxins ; Paresthesia ; Permeability ; Respiration, Artificial ; Saxitoxin* ; Shellfish ; Shellfish Poisoning* ; Vomiting

AIMTo isolate and purify gonyautoxins from Alexandrium mimutum Halim Amtk2 strain.

METHODSThe ethanol extracts of culture Alexandriun minutum Halim Amtk2 were isolated by means of gel filtration chromatography, the toxin fraction obtained was then purified by ion exchange chromatography.

RESULTSFrom 100 liter of cultivation liquid of Alexandrium mimutum Halim Amtk2 (6.74 +/- 0.31) x 10(9) cells were obtained. The ethanol extracts of Alexandriun minutum Halim purified by gel filtration chromatography obtained gonyautoxins mixture 29.59 mg. 4.06 mg of the mixture was further purified by two steps of ion exchange chromatography, and obtained pure GTX-4 (0.40 +/- 0.002) mg, GTX-1 (5.95 +/- 0.03) x 10(-2) mg, GTX-3 (6.92 +/- 0.05) x 10(-4) mg and GTX-2 (0.11 +/- 0.005) mg.

CONCLUSIONPure gonyautoxins can be obtained by means of gel filtration chromatography and ion exchange chromatography from ethanol extracts of cultured Alexandriun minutum Halim Amtk2 strain.

Animals ; Chromatography, Gel ; methods ; Chromatography, Ion Exchange ; Dinoflagellida ; chemistry ; Marine Toxins ; chemistry ; isolation & purification ; Molecular Structure ; Saxitoxin ; analogs & derivatives ; chemistry ; isolation & purification