Toxicity, morphology and distribution of Pseudo-nitzschia calliantha, P. multistriata and P. multiseries (Bacillariophyta) from the northwestern Sea of Japan

• Toxicity, morphology and distribution patterns of three bloom-forming species of the diatom genus Pseudo-nitzschia (potential producers of the neurotoxin domoic acid and causative organisms of amnesic shellfish poisoning) from Peter the Great Bay in the northwestern Sea of Japan are presented. Pseudo-nitzschia calliantha, P. multistriata and P. multiseries bloomed in Peter the Great Bay in the fall, with abundances exceeding 10(6) cells l(-1). This is the first report of toxicity in P. multiseries from Russian waters. Domoic acid was found in stationary-phase (days 20-35) cultures of P. multiseries isolated from Peter the Great Bay at concentrations varying between 180 and 5390 ng ml(-1) or 2 to 21 pg cell(-1), which is in the range reported for other isolates of P. multiseries. The Russian isolate had an increasing ability to produce domoic acid over time in culture rather than the usual trend of decreasing toxicity. No domoic acid was detected (< ;2 ng ml(-1)) in cultures of P. calliantha and P. multistriata from the same locality. The Russian isolate of P. multiseries produced gametes when mated with the Canadian strains of the opposite mating type, but they never developed into zygotes, auxospores or large initial cells. This suggests that there might be "cryptic'' species within P. multiseries. However, a comparison of molecular and morphometric data between the Russian and Canadian strains showed that they indeed belong to the same species.

Ämnesord

NATURVETENSKAP  -- Biologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences (hsv//eng)

Nyckelord

diatoms

domoic acid

gametogenesis

internal transcribed spacer rDNA

Pseudo-nitzschia

Biology

Biologi

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)