Brown, Jr. R. M. 1975. Pleurochrysis scherffelii (Haptophyceae). Vegetative development. Encyclopaedia Cinematographica. Film E 1682 des Inst. Wiss. Film, Göttingen. Research Film 8:491-500.

General Remarks:
Pleurochrysis scherffelii was described as a chrysophycean alga by PRINGSHEIM in 1955. The alga subsequently was placed in the family Phaeothamniaceae by POTT. When PRINGSHEIM described this alga, no zoospore stages were known. Therefore, any haptophycean affinities of this organism could not be confirmed. This was further complicated by the fact that no one had observed the ultrastructure of Pleurochrysis. In 1969, BROWN discovered that Pleurochrysis produces scales which are very similar to those known for the Haptophyceae. Later investigations by BROWN et al. revealed motile stages demonstrating a very short haptonema located between two smooth flagella. Although no formal transfer into the Haptophyceae has been made, Pleurochrysis probably should be considered within this class. Recently, BROWN and BLANKLEY (work in progress) were successful in obtaining coccolith stages from Pleurochrysis cultures. These observations strongly suggest that Pleurochrysis is an alternant phase with the: coccolith-producing haptophycean alga, Cricosphaera. Until the life history of this interesting organism is more thoroughly investigated, the writer would like to defer a formal description.


From:Journal of Marine Biotechnology
By: Megumi Okazaki A1, Tatsuya Sato A1, Naoko Mutho A1, Norio Wada A2, Takao Umegaki


The fine structure and crystallographic nature of coccoliths from the alga Pleurochrysis carterae were studied. Each subelliptical coccolith is about 2 7m long and consists of about 12 anvil-shaped large (A) and small (B) elements situated on the rim of an organic base-plate. The A and B elements alternate and interlock. Each element is a single calcite crystal, and the A and B elements have their c axis radial and vertical to the coccolith plane, respectively. The structure of this coccolith is explained well by the V/R model proposed by others: the large and small anvil-shaped crystals are thought to have grown from a simple calcite crystal, R and V, respectively. Acid polysaccharide associated with coccoliths was also studied. A single acid polysaccharide was extracted with EDTA from isolated coccoliths as well as coccoliths without organic base-plates, whereas two acid polysaccharides (PA and PB) were obtained from whole cells. The profiles of the coccolith-associated polysaccharide were consistent with that of PB on DEAE-cellulose chromatography as well as on polyacrylamide gel electrophoresis, but a less inhibitory effect on CaCO3 precipitation than PB in vitro was demonstrated. PB was the most inhibitory of these three polysaccharides. This suggests that PB contains a highly inhibitory acid polysaccharide of intracellular origin, possibly from the calcifying site. The possible roles of these acid polysaccharides are discussed in relation to coccolith formation.

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