Pseudo-nitzschia multiseries

Zheng, N. Shimizu, Y. (1997) The isolation and structure of bacillariolide III, an extracellular metabolite of the diatom, Pseudo-nitzschia multiseries. Chem. Commun. 399-400. 

Figure 37.4 Replicate Pseudo-nitzschia multiseries cultures were grown under 24 h light (100 tmol photons s ) at 15 °C for 4 days as an auxostat (chemostat with growth limited by pump rate) with Si-limited f/2 media. On day -4, the pumps were turned off, forcing the cultures into Si-limitation. On days 0, 4 Si-spikes (10 pM) were added. On day 5, trace-metals (f/2 stock) was added, with no apparent response. Optical density (cell abundance) and variable fluorescence were determined from a PAM fluorometer and are plotted versus time (dashed vertical lines indicate additions of unenriched seawater dashed horizontal line indicates maximal Fv/Fm values in healthy cells). A rapid decline and recovery of variable fluorescence indicates impaired photosynthetic performance, and functionally mimics the response of Fe-limitation, with recovery times dependent on the length of time spent in Si-deprived conditions.

In 1987, the first confirmed case of a naturally occurring neurotoxic diatom bloom was reported in Prince Edward Island, Canada, later confirmed to be caused by the production of domoic acid from the pennate diatom Nitzschia pungens, now renamed Pseudo-nitzschia multiseries (Bates et ah, 1989 Subba Rao et ah, 1988). Since this first outbreak, many (but not aU) species of Pseudo-nitzschia have been confirmed to produce domoic acid (as well as some species of Amphora and now Nitzschia (Kotaki et ah, 2000) see Bates, 1998, 2000, for a summary). These potentially toxic species include P. multiseries, P. pseudodelicatissima, P. delicatissima, P. seratia, P. australis, P. pungens, and P.fraudulenta, although it is apparent that not aU species are toxic in aU locations, nor are individual strains toxic under aU conditions. 

Maldonado, M., Hughes, M., Rue, E., and Wells, M. (2002). The effect of Fe and Cu on the growth and domoic acid production of Pseudo-nitzschia multiseries and Pseudo-nitzschia australis. Limnol. Oceanogr. 47, 515—526. 

Pan, Y., Subba Rao, D., and Mann, K. (1996a). Changes in domoic acid production and cellular chemical composition of the toxigenic diatom Pseudo-nitzschia multiseries under phosphate limitation. J. Phycol. 32, 371-381. 

Kotaki, Y, et al. Confirmation of domoic acid prodnction of Pseudo-nitzschia multiseries isolated from Ofunato Bay, Japan. Toxicon, 37, 677-682 (1999). 

The species Nitzschia pungens form a multiseries, at the origin of the mortal intoxications of 1987, was renamed Pseudo-nitzschia multiseries. An agonist is a substance that has the same mode of action as the control. When the action is the opposite, the substance is known as an antagonist. 

After the finding of P. multiseries, screenings of pennate diatom that produces DA were performed mainly in temperate and cold-water areas, and resulted in reporting several kinds of Pseudo-nitzschia spp. as described in the next section (Table 19.1). 

Reobservation of the HPLC chromatogram of N. navis-varingica isolates from several areas in the Philippines showed that only isolates from Bnlacan estuary produced isodomoic acids A (lA) and B (IB) instead of DA, and all of the isolates from other areas prodnced DA and IB. It seemed to be interesting to solve whether N. navis-varingica isolated from other areas ontside the Philippines also produces lA or IB and DA. And it also seemed to be interesting to know whether P. multiseries or some other Pseudo-nitzschia could produce DA derivatives such as lA and IB. 

Domoic acid Pseudo-nitzschia australis, seriata, pungens, multiseries... 

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