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Protistology ■ 25
THE PARASITIC ASSIMILATION FROM DIATOMS BY APLANOCHYTRIUM (THRAUS-TOCHYTRIIDAE, LABYRINTHULEA, STRA-MENOPILES) Hamamoto Y.12, Honda D.32
1 - Graduate School of Natural Science, Konan University, Japan
2 - Institute for Integrative Neurobiology, Konan University, Japan
3 - Faculty of Science and Engineering, Konan University, Japan [email protected] Thraustochytrids inhabit the ocean all over the world and have been recognized as important eukaryotic decomposers in the marine ecosystem. The monitoring works have suggested that they obtain nutrients from the terrestrial organic matter at estuarine areas. On the other hand, the habitat ofthe thraustochytrids is spread over the coastal areas, in which there are almost no influences from terrestrial fields. This suggests that the nutrition source of the thraustochytrids in the coastal areas is the detritus of phytoplankton. In this study, we investigated the assimilation of the thraustochytrids from diatoms, which are important primary pro-ducers in the coastal areas. First, we examined growth tests of the thraustochytrids under the 2-membered culture condition with Skeletonema diatoms. As the result, Aplanochytrium strains have quite higher growth than 8 other genus-level groups of the thraustochytrids. Observation under light microscopy showed that the vegetative cells of Aplanochytrium extended the pseudopod-like ectoplasmic nets to the diatom cells, and then chloroplasts ofthe diatoms shrank and bleached. It was suggested that the thraustochytrids play the role as not only decomposers but also "predators". Moreover, Aplanochytrium cells pulled the diatom cells and made aggregates, which are suited to be baits for juvenile fishes. It is possible that the food chain pathway of the Aplanochytrium has a large impact on the marine ecosystem because there are few steps in the food chain between the producers and the higher consumers.
A RE-INVESTIGATION OF THE PELAGO-PHYTE GENUS SARCINOCHRYSIS USING MATERIAL COLLECTED FROM THE TYPE LOCALITY
Han K.Y.1, Melkonian M.2, Andersen R.A.3, Graf L.1, Pérez Reyes C.4, Yoon H.S.1
1 - Department of Biological Sciences, Sungkyunkwan University, Suwon 16419, Korea
2 - Botany Department, Cologne Biocenter, University of Cologne, Zülpicher Str. 47b, 50674 Cologne, Germany
3 - Friday Harbor Laboratories, University of Washington, Friday Harbor, WA 98250 USA
4 - Spanish Bank of Algae — Marine Biotechnology Center (BEA-CBM), University of Las Palmas de Gran Canaria, Muelle de Taliarte s/n, 35214, Telde, Las Palmas, Gran Canaria, Spain [email protected]
Modern systematists use molecular markers to identify and distinguish species; however, many microalgae were described before gene sequencing was invented and the holotype was often an ink drawing. Cryptic speciation and biogeographic isolation are potential problems when anchoring an old species name with a modern gene sequence. Therefore, to avoid possible confusion caused by a misidentified microalgal culture from a different locality, the best approach is to sequence genes from the alga re-collected from the type locality. The marine alga Sarcinochrysis marina was described in 1930 by Geitler from the Canary Islands, Spain; Geitler used two cultures in his study, but these cultures no longer exist. Sarcinochrysis marina is the oldest genus in the Pelagophyceae. We re-isolated S. marina from the type locality near Las Palmas, Gran Canaria. Furthermore, we included additional Pelagophyceae strains that were obtained from culture collections. We produced a total of 109 sequences, representing the nuclear-encoded SSU rRNA and the plastid encoded rbcL, psaA, psaB, psbA, and psbC genes. The sequences were used to infer maximum likelihood phylogenetic trees. We anchored the genus Sarcinochrysis using the Las Palmas isolate, and we discovered several undescribed genera and species that are morphologically similar to Sarcinochrysis.
UNEXPECTED DIVERSITY OF THE PECULIAR GENUS CRENEIS (EXCAVATA: HETE-ROLOBOSEA) Hanouskova P., Cepicka Ivan Department ofZoology, Charles University in Prague, Prague, Czech Republic [email protected],
Creneis is a recently (2014) discovered genus of marine anaerobic heteroloboseids. Its only species, C. carolina, displays several uncommon features including amoeboid flagellates with a single flagel-lum, a multiflagellate form with ca. 14 flagella and the unique structure ofits flagellar apparatus. Therefore, its affiliation to Heterolobosea is recognizable only thanks to the results ofmolecular-phylogenetic analyses. Creneis was described on the basis of a single isolate and has never been observed again. We have established six marine Creneis strains in culture. According to the morphology and SSU rRNA gene
