Analysis of toxic and non-toxic Alexandrium (Dinophyceae) species using ribosomal RNA gene sequences

Scholin, Christopher A.

doi:10.1575/1912/5529

Cited by 22 publications

(20 citation statements)

References 21 publications

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“…Again, it would be interesting to study the phylogcny of these diatoms, for example with RNA probes (cf. Scholin & Anderson 1993). P. subcurvata (Clones CCMP1437 and CCMP1444) also labelled siightly, but at least 1 of these clones (CCMP1437 = MC-2) did not produce domoic acid at a detection limit of 3.28 fg cell-' (Fryxell et al 1991).…”

Section: Discussionmentioning

confidence: 98%

“…In another instance, our immunofluorescence assay correctly showed that the idenbfications of 2 P. pungens clones from New London Bay, PEI, had inadvertently been reversed. Such assays may therefore also serve as a check on the taxonomic identifications of phytoplankton, analogously to the way in which RNA or DNA sequences can be used to separate Alexandrium species (Scholin & Anderson 1993).…”

Section: Discussionmentioning

confidence: 99%

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Discrimination between domoic-acid-producing and nontoxic forms of the diatom Pseudonitzschia pungens using immunofluorescence

Bates¹,

Léger²,

Keafer³

et al. 1993

Mar. Ecol. Prog. Ser.

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Separate polyclonal antibodies were developed against cell surface antigens of the 2 forms of the pennate diatom Pseudonitzschia (previously known as N~tzschia) pungens, i.e. forma multiseries (the domoic-acid-producing form) and forma pungens (the nontoxic form). Positive antigenic reactions were visualized with epifluorescence microscopy, using a fluorescein isothiocyanate (FITC) indirect immunofluorescence assay. The assay successfully distmguished 31 clones of f . multiseries from the l ? clones of f. pungens tested, with no cross reactions of the antisera between the 2 forms. The antisera were active against P, pungens cells isolated from Prince Edward Island and Nova Scotia, Canada, and Massachusetts, Rhode Island, Texas and Washington. USA. Of the 27 other clones tested from the genera Pseudonitzschia and Nitzschia, 2 other domoic-acid-producing species (P. australis and P. pseudodelicatissima) and 2 nontoxic species (P. subcurvata and P. fraudulenta) showed a slight positive response to the antisera, as did the domoic-acid-producing pennate diatom Amphora coffaeiformis. These reactions are not great enough to cause concern about misidentification, but pose questions about phylogenic relationships. Other representatives from the class Bacillariophyceae and from 8 other major classes of phytoplankton did not cross react with the antisera. Excellent labelling was obtained with live cells and those frozen at -6OoC, or preserved in 2 % glutaraldehydeparaformaldehyde, 2 % borate-buffered formalin or 2 % paraformaldehyde. Immunofluorescence shows great promise as a technique to distinguish between the 2 forms of P. pungens for research and monitoring purposes.

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Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

Discrimination between domoic-acid-producing and nontoxic forms of the diatom Pseudonitzschia pungens using immunofluorescence

Bates¹,

Léger²,

Keafer³

et al. 1993

Mar. Ecol. Prog. Ser.

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“…It has been suggested much earlier that typical A. tamarense do not produce PSP toxins (Boyer et al, 1985;Balech, 1995). However, one clone from Thailand was reported as toxic by Scholin (1993). Further studies need to be carried out to establish whether temperate and tropical A. tamarense isolates should be taxonomically separated, and if non-toxicity is a common feature of the tropical isolates.…”

Section: Discussionmentioning

confidence: 99%

Alexandrium (Dinophyceae) species in Malaysian waters

et al. 2002

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A study was carried out to determine the presence of paralytic shellfish poisoning (PSP) toxin-producing dinoflagellates in the coastal waters of Peninsula Malaysia. This followed first ever occurrences of PSP in the Straits of Malacca and the northeast coast of the peninsula. The toxic tropical dinoflagellate Pyrodinium bahamense var. compressum was never encountered in any of the plankton samples. On the other hand, five species of Alexandrium were found. They were Alexandrium affine, Alexandrium leei, Alexandrium minutum, Alexandrium tamarense and Alexandrium tamiyavanichii. Not all species were present at all sites. A. tamiyavanichii was present only in the central to southern parts of the Straits of Malacca. A. tamarense was found in the northern part of the straits, while A. minutum was only found in samples from the northeast coast of the peninsula. A. leei and A. affine were found in both the north and south of the straits. Cultured isolates of A. minutum and A. tamiyavanichii were proven toxic by the receptor binding assay for PSP toxins but A. tamarense clones were not toxic. Mean toxin content for the A. tamiyavanichii and A. minutum clones were 26 and 15 fmol per cell STX equivalent, respectively. This study has provided evidence on the presence of PSP toxin-producing Alexandrium species in Malaysian waters which suggests that PSP could increase in importance in the future.

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“…Toxic species of the genus Alexandrium are spread widely throughout many regions of the world (10,17,18,21,22). Within this genus, members of A. catenella/tamarense/ fundyense (known as the tamarensis complex) (18) are among the most toxic species. In Chile, the first documented toxic bloom was reported in 1972 in the Magallanes region (7).…”

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confidence: 99%

Effect of Associated Bacteria on the Growth and Toxicity of Alexandrium catenella

Uribe

Espejo

2003

Appl Environ Microbiol

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Saprophytic bacteria in cultures of the marine dinoflagellate Alexandrium catenella were removed to assess their effect on growth and paralytic shellfish poisoning toxin production of this dinoflagellate. The actual axenic status was demonstrated by the lack of observable bacteria both immediately after treatment and following extended incubation in the absence of antibiotics. Bacteria were measured by counting CFU and also by epifluorescence microscopy and PCR amplification of bacterial 16S-23S spacer ribosomal DNA to detect noncultivable bacteria. Removal of bacteria did not have any effect on the growth of the dinoflagellate except for the inhibition of A. catenella disintegration after reaching the stationary phase. Toxicity was determined in dinoflagellate cell extracts by different methods: high-performance liquid chromatography (HPLC); an electrophysiological test called the Electrotest, which measures the inhibition of saxitoxin-sensitive Na ؉ channels expressed in a cell line; and a mouse bioassay, which measures the toxic effect on the whole mammal neuromuscular system. A lower toxicity of the dinoflagellates in axenic culture was observed by these three methods, though the difference was significant only by the mouse bioassay and HPLC methods. Altogether the results indicate that axenic cultures of A. catenella are able to produce toxin, though the total toxicity is probably diminished to about one-fifth of that in nonaxenic cultures.

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Analysis of toxic and non-toxic Alexandrium (Dinophyceae) species using ribosomal RNA gene sequences

Cited by 22 publications

References 21 publications

Discrimination between domoic-acid-producing and nontoxic forms of the diatom Pseudonitzschia pungens using immunofluorescence

Discrimination between domoic-acid-producing and nontoxic forms of the diatom Pseudonitzschia pungens using immunofluorescence

Alexandrium (Dinophyceae) species in Malaysian waters

Effect of Associated Bacteria on the Growth and Toxicity of Alexandrium catenella

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