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Hanic-The 1987 PEI Toxic Mussel Episode-A Personal Perspective-March 2014-Stephen S Bates Editor
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. An outbreak of food poisoning in Canada during autumn 1987 was traced to cultured blue mussels (Mytilus edulis) from the Cardigan Bay region of eastern Prince Edward Island (P.E.I.). The toxin, identified as domoic acid, had not previously been found in any shellfish and this outbreak represents the first known occurrence of human poisoning by this neurotoxin. A plankton blooln at the time of the outbreak consisted almost entirely of the pennate diatom, Nitzschia pungens f. multiseries,~nd a positive correlation was found between the number of N. pungens cells and the concentration of domoic acid in the plankton. Nitzschia pungens f. multiseries isolated from Cardigan Bay produced domoic acid in culture at levels (1 to 20 pg-cell ") comparable with values estimated for N. pungens in the plankton samples. Isolates of several Cardigan Bay phytoplankton, including the closely related species Nitzschia seriata, failed to produce domoic acid. Other Nitzschia spp. and two Amphora cof feaeformis isolates also failed to produce domoic acid. We conclude that N. pungens was the major source of the domoic acid in toxic mussels in eastern P.E.I. The recurrence, in November 1988, of a monospecific bloom of N. pungens and the presence of domoic acid in plankton and mussels reinforced this conclusion.
Prasiola meridionalis (S. & G.) and Rosenvingiella constricta (S. & G.) Silva overlap in dense, almost pure stands at Porlier Pass, Galiano Island, B.C. Ten clones of each, established from single spores, reproduced true to type through eleven generations spread over a six-year period. This supports the view that Prasiola and Rosenvingiella are distinct genera. Earlier published data supporting an interconnection of the two forms, especially that of Bravo, Friedmann and Edwards is examined and found wanting. Retention of the two genera, as advocated by Kornmann and Sahling is supported.
2005. The phylogeny of North American Urospora (Ulotrichales, Chlorophyta) based on sequence analysis of nuclear ribosomal genes, introns and spacers. Phycologia 44: 194–201. Amplification of the ribosomal cistron of Urospora isolates from within the 18S ribosomal RNA (rRNA) gene through the internal transcribed spacer (ITS) and 5.8S regions into the 28S rRNA gene produced fragments of varying lengths. The lengths depended on the absence or presence of up to three group I introns, located at positions 943, 989 and 1512 of the 18S rRNA gene (positions based on the Escherichia coli sequence). The 943 and 1512 introns belong to subgroup IC1 and the 989 intron to subgroup IE. Introns occurred in all species except U. penicilliformis. Intron sequence data and phylogenetic analyses based on the intron sequences supported recognition of the same species groups as the ITS data and helped resolve relationships between the species. Urospora penicilliformis, U. wormskioldii and two undescribed taxa ('Aberdeen' and 'Viking') occurred in one clade, and U. neglecta in a separate clade. Pacific U. neglecta differed from Atlantic U. neglecta in both intron sequence and occurrence. The 18S rRNA gene sequences (excluding the introns) were identical in all species except for one autapomorphy each in U. neglecta, U. wormskioldii, Aberdeen and Viking and one synapomorphy in U. neglecta, U. penicilliformis and Viking. Comparisons of this gene with other ulvophycean taxa support the placement of Urospora in the Acrosiphoniaceae, order Ulotrichales. The uninucleate genus Chlorothrix rather than the multinucleate Acrosiphonia is the genus closest to Urospora.
We cultured a tubular marine green alga, originally identified as Capsosiphon groenlandicus (J. Agardh) K.L. Vinogradova, from Amaknak Island, Alaska. The alga had an alternation of heteromorphic generations in which tubular monoecious fronds produced quadriflagellate zoospores and/or biflagellate isogametes. The gametes fused to produce cysts or Codiolum-like zygotes with long, tortuous stalks. Cysts and codiola produced 8-16 aplanospores, which germinated in situ to yield upright fronds. Fronds arising from both aplanospores and zoospores displayed a distinctive development in which non-septate colorless rhizoids from the base of the initially uniseriate, Ulothrix-like filament were transformed into septate uniseriate Ulothrix-like photosynthetic filaments. These transformed filaments then developed new basal non-septate rhizoids. This pattern of rhizoids becoming filaments, which then produced new rhizoids, was repeated to yield a tuft of up to 50 fronds. Periclinal and longitudinal divisions occurred in each filament, starting basally, until the mature tubular thallus was achieved. Pyrenoid ultrastructure revealed several short inward extensions of chloroplast lamellae, each of which was surrounded by pyrenoglobuli. Analysis of ribosomal SSU and ITS sequences placed this alga in the family Ulotrichaceae, order Ulotrichales, together with but as a distinct species from North Atlantic Capsosiphon groenlandicus. Analysis of a partial ITS sequence from authentic Capsosiphon fulvescens, the current name of the type of the genus Capsosiphon, indicated that neither our material nor C. groenlandicus belongs in that genus, and we propose a new genus, Pseudothrix, to accommodate both species. We propose P. borealis for the North Pacific entity formerly called C. groenlandicus and make the new combination P. groenlandica for the Atlantic species.
The genus Pseudo-nitzschia contains potentially toxic species of problematic taxonomy, making it one of the most intensively studied diatom genera. The study of 35 clonal strains isolated from the Bilbao estuary, an area that experiences recurrent blooms of Pseudo-nitzschia, revealed the presence of two new species, P. abrensis and P. plurisecta, differing from their congeners in both morphology and gene sequence. The morphological features were analyzed by LM and EM, whereas molecular analyses were based on the internal transcribed spacer (ITS) and large subunit (LSU) regions of the rDNA. P. plurisecta appears closely related to P. cuspidata/P. pseudodelicatissima in the phylogenetic tree, whereas P. abrensis forms a moderately supported clade with P. heimii/P. subpacifica and P. caciantha/P. circumpora. Comparison of the secondary structure of ITS2 regions reveals marked differences in the most highly conserved regions among related taxa. Morphologically, the new species differ from their closest congeners in the arrangement of the poroid sectors and the density of valve striae and fibulae. The two species share similar pigment composition, and belong to the group of Pseudo-nitzschia species containing only chlorophyll c2 and c3.
A study on the morphology and phylogeny of 18 strains of Pseudo-nitzschia established from the Strait of Malacca, Peninsular Malaysia, was undertaken. Morphological data combined with molecular evidence show that they constitute three new species, for which the names, P. batesiana sp. nov., P. lundholmiae sp. nov., and P. fukuyoi sp. nov., are proposed. The three new species closely resemble species in the P. pseudodelicatissima complex sensu lato. Morphologically, P. batesiana differs from other species in the complex by having a smaller part of cell overlapping in the chain, whereas P. lundholmiae differs by having fewer poroid sectors and P. fukuyoi by having a distinct type of poroid sectors. Nucleotide sequences of the LSU rDNA (D1-D3) of the three new species reveal significant nucleotide sequence divergence (0.1 to 9.3%) from each other and from other species in the P. pseudodelicatissima complex s.l. The three species are phylogenetically closely related to species in the P. pseudodelicatissima complex, with P. batesiana appearing as a sister taxon to P. circumpora, P. caciantha and P. subpacifica; while P. lundholmiae and P. fukuyoi are more closely related to P. pseudodelicatissima and P. cuspidata. The three species show 2-3 compensatory base changes (CBCs) in their ITS2 transcripts when compared to the closely related species. The ITS2 with its structural information has proven its robustness in constructing a better resolved phylogenetic framework for Pseudo-nitzschia.
Filament and gamete morphology, mating tests and hybridizations reveal the presence of eight taxa of Urospora from the Pacific and Atlantic coasts of North America. Three are dioecious and anisogamous: U. penicilliformis, U. neglecta and U. wormskioldii (synonym: U. vancouveriana). A fourth, U. bangioides, is monoecious and isogamous. Two are unisexual female variants, one with biflagellate parthenogametes (both coasts) and the other with quadriflagellate parthenogametes (Atlantic coast only). Two others are unidentified monoecious, anisogamous variants: one on the Atlantic coast and one on the Pacific coast. Urospora penicilliformis, U. neglecta and U. wormskioldii from the Pacific formed viable hybrids with their Atlantic counterparts and are considered to be conspecific with them. Urospora penicilliformis from the Pacific coast also formed viable hybrid zygotes with U. penicilliformis from Helgoland and Japan, again indicating conspecificity. On the Pacific coast, U. penicilliformis is the most common Urospora in the upper littoral, ranging from southern California to Homer, Alaska, with U. neglecta being restricted to British Columbia and Alaska. On the Atlantic coast, U. neglecta is the dominant Urospora, with U. penicilliformis subdominant ill the upper littoral. Urospora wormskioldii is the dominant Urosporo in the lower littoral on both coasts. Sexuality is reported for the first time in U. wormskioldii and for the first time in North America in U. bangioides. Monoecy and isogamy are confirmed in the genus. Urospora penicilliformis, U. neglecta and U. wormskioldii, although usually dioecious, are occasionally monoecious, indicating that the dioecious condition in these three species is not fixed. Emended descriptions of the species and genus are provided.
SUMMARYA chemically resistant cuticle fraction was isolated from 5 phaeophycean, 1 rhodophycean, and 11 chlorophycean marine algae using acid treatment alone, or acid treatment followed by leaching in cupra-ammonium. In Cladophora rupestris and Chaetomorpha melagonium this fraction consists of several alternate microfibrillar and amorphous layers similar in appearance to those seen in innermost carbohydrate-rich regions and amount to about 1/10 or more of the cell wall thickness. In Porphyra umbilicalis and Padina vickersiae it is a single layer less than I μ thick, accounting for 1/50–1/100 of the cell wall in Porphyra, and 1/5–1/10 of the cell wall in Padina. The cuticle fractions of all 4 algae contain surprisingly large amounts of protein (about 70% in Cladophora and 80% in Porphyra). Similarities in the behavior of cuticles obtained from the other 12 species studied suggest that they may have a similar protein-rich composition.