|
" The physiology and toxicity of the red tide dinoflagellate Pyrodinium bahamense var. compressum "
G. Usup
J. Atema
| Document Type
|
:
|
Latin Dissertation
|
| Language of Document
|
:
|
English
|
| Record Number
|
:
|
1113471
|
| Doc. No
|
:
|
TLpq304162473
|
| Main Entry
|
:
|
G. Usup
|
|
|
:
|
J. Atema
|
| Title & Author
|
:
|
The physiology and toxicity of the red tide dinoflagellate Pyrodinium bahamense var. compressum\ G. UsupJ. Atema
|
| College
|
:
|
Boston University
|
| Date
|
:
|
1995
|
| student score
|
:
|
1995
|
| Degree
|
:
|
Ph.D.
|
| Page No
|
:
|
168
|
| Abstract
|
:
|
The red tide dinoflagellate Pyrodinium bahamense Plate var. compressum Bohm is the causative organism responsible for most paralytic shellfish poisoning (PSP) events in the tropical Pacific. Little information is available on the physiology and toxin production characteristics of P. bahamense due to failures in establishing laboratory cultures. In this study, a P. bahamense isolate from Malaysia was successfully cultured in a modified version of Provasoli's enriched-seawater medium. Typical culture yields were 5000-6000 and 1500-2000 cells mL in medium with and without soil extract supplement, respectively. Soil extract most likely served as a source of selenium, which increased cell yield in a manner similar to the soil extract additions. Division rates ranged from 0.25 to 0.4 div. day which are typical for dinoflagellates in culture. The isolate grew from 22 to 34C, with optimum growth at 28C. Salinities of 24usd\perthoususd or higher were required for growth. Analysis by high performance liquid chromatography showed that the isolate produced saxitoxin, neosaxitoxin, decarbamoyl-saxitoxin, and gonyautoxins 5 and 6. Neosaxitoxin and gonyautoxin 5 comprised 30 mole percent or more of the total toxin content (measured in fmol cell under all growth conditions. During growth in nutrient-replete medium, toxin content peaked in early exponential phase. Toxin content increased with decreasing growth temperature, and was not affected by variations in salinity, except at the lowest salinity tolerated (20usd\perthous),usd where toxin content increased three-fold. When growth was limited by low light intensity, toxin content decreased, accompanied by an increase in chlorophyll-a content. Toxin content was higher in phosphorus-limited compared to phosphorus-sufficient cultures. Nitrogen limitation did not result in reduced PSP toxin production. Significant changes in the relative proportion of each PSP toxin derivative per cell were found as temperature, light intensity, nitrate concentration, and phosphate concentration were varied. Pyrodinium bahamense is a fastidious species to culture and the optimum culture medium for the species has yet to be determined. It was evident that growth conditions significantly affected toxin production in the species. Toxin production in P. bahamense showed several similarities to production in Alexandrium spp. and Gymnodinium catenatum, but there were also significant differences.
|
| Subject
|
:
|
Biological sciences
|
|
|
:
|
Ecology
|
|
|
:
|
Malaysia
|
|
|
:
|
Oceanography
|
| |