Pseudo-nitzschia

Miller P, Scholin C. Identification and enumeration of cultured and wild Pseudo-nitzschia (Bacillariophyceae) using species-specific LSU rRNA-targeted fluorescent probes and filter-based whole cell hybridization. J Phycol 1998 34 371-382. 

Dinoflagellates Dinophysis spp., Prorocentrum lima Diatoms Pseudo-nitzschia spp. Dinoflagellates Protoperidinium spp. Epibenthic dinoflagellates Gambierdiscus toxicus Possibly Ostreopsis spp. Coolia spp. or Prorocentrum spp. 

Domoic acid (Fig. 28,80) (263) is a neuro-phycotoxin responsible for the mortality of wildlife and for amnesic shellfish poisoning (ASP) of humans during algal bloom. Domoic acid was first isolated from the red alga Chondria armata ( domoi in Japanese), and it is produced also by diatoms, such as Pseudo-nitzschia spp. For the latter, evidence has been presented that it is involved in iron acquisition (307). 

Rue E, Bmland K (2001) Domoic Acid Binds Iron and Copper a Possible Role for the Toxin Produced by the Marine Diatom Pseudo-nitzschia. Mar Chem 76 127... 

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. 

Evans KM, Hayes PK (2004) Microsatellite markers for the cosmopolitan marine diatom Pseudo-nitzschia pun-gens. Mol Ecol Note 4 125-126... 

Keywords Biomass estimate, colonies Colonization Phaeocystis bloom Pseudo-nitzschia species... 

During our studies, we observed an abundance of the small needle-shaped Pseudo-nitzschia species on Phaeocystis colonies provoking interest in both qualitative and quantitative analysis of this phenomenon. If Pseudo-nitzschia species comprise a significant fraction of total Phaeocystis colony biomass, it is essential to take this fact into consideration in the studies of food webs, vertical fluxes, biogeochemical element fluxes, etc. since Phaeocystis is a widely distributed phytoplankter and it often develops massive blooms (Schoemann et al. 2005). 

In a recent article (a combination of the morphological and molecular findings) Pseudo-nitzschia delicatissima was shown to be a complex of three different species (Pseudo-nitzschia delicatissima, P. decipiens sp. nov. and P. dolorosa sp. nov. (Lundholm et al. 2006). 

Fig. 3 (a-c) Diatom Pseudo-nitzschia delicatissima inhabiting the surface of the Phaeocystis globosa colonies from the Eastern English Channel (a light microscopy, b epiflu-orescence microscopy, c scanning electron microscopy)... 

Fig. 4 Bloom and evolution of Phaeocystis glob-osa colonies and diatom Pseudo-nitzschia delica-tissima from the Eastern English Channel in 2003 and 2004...

Fig. 5 (a, b) Diatom Pseudo-nitzschia cf. granii var. curv-ata inhabiting the surface of Phaeocystis pouchetii colonies from Western Norway (light microscopy)... 

Fig. 6 Bloom and evolution of Phaeocystis pouch-etii colonies (a) and diatom Pseudo-nitzschia cf. granii var. curvata (b) from Western Norway. The squares refer to the number of colonies and the circles to the average size of the colonies...

Hasle GR, Syvertsen EE (1997) Marine Diatoms. In Tomas CR (ed) Identifying marine phytoplankton. Academic Press, San Diego, pp 5-385 Hasle GR, Lange CB, Syvertsen EE (1996) A review of Pseudo-nitzschia, with special reference to the Skager-rak, North Atlantic, and adjacent waters. Helgol Meeres 50 131-175... 

Lundholm N, Moestrup 0, Kotaki Y, Hoef-Emden K, Scholin C, Miller P (2006) Inter- and intraspecific variation of the Pseudo-nitzschia delicatissima complex (Bacillariophyceae) illustrated by RRNA probes, morphological data and phylogenetic analyses. J Phycol 42 464—481... 

Priisholm K, Moestrup 0, Lundholm N (2002) Taxonomic notes on the marine diatom genus Pseudo-nitzschia in the Andaman Sea near the island of Phuket, Thailand, with a description of Pseudo-nitzschia micropora sp. nov. Diatom Res 17(1) 153—175 Proshkina-Lavrenko AI (1963) Benthic Diatoms of the Black Sea. Academy of Sciences of the USSR, Mos-cow-Leningrad, 237 p (in Russian)... 

Bates, S.S. 2003. Domoic acid and Pseudo-nitzschia References. Department of Fisheries and Oceans Canada. 

Holland, P.T., Selwood, A T, Mountfort, D.O., Wilkins, A.L., McNabb, E, Rhodes, L.L., Doucette, G.J., Mikulski, C.M., and King, K.L. 2005. Isodomoic acid C, an unusual amnesic shellfish poisoning toxin from Pseudo-nitzschia australis. Chem Res Toxicol 18, 814-816. 

Pan, Y., Bates, S. S., and CembeUa, A. D. (1998). Environmental stress and domoic acid production by Pseudo-nitzschia A physiological perspective. Nat. Toxins. 6, 127—135. 

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. 

---