CC BY
41
30 • "PROTIST—2016
OBSERVATION OF ZOOSPORE SETTLEMENT FOCUSING ON THE DEVELOPMENT OF ACTIN FILAMENTS (LABYRINTHULEA, STRAMENOPILES)
Iwata I.12, Kimura K.3, Tomaru Y.4, Motomura T.5, Koike Kana6, Koike Kazu7, Honda D.28
1 - Graduate School of Natural Science, Konan University, Japan
2 - Institute for Integrative Neurobiology, Konan University, Japan
3 - Institute of Lowland and Marine Research, Saga University, Japan
4 - National Research Institute of Fisheries and Environment ofInland Sea, Japan Fisheries Research and Education Agency, Japan
5 - Muroran Marine Station, Field Science Center for Northern Biosphere, Hokkaido University, Japan
6 - Natural Science Center for Basic Research and Development, Hiroshima University, Japan
7 - Graduate School of Biosphere Science, Hiroshima University, Japan
8 - Faculty of Science and Engineering, Konan University, Japan d1422001@s.konan-u.ac.jp
The Labyrinthulea is characterized by an ectoplas-mic net (EN) system. The nets are superficially similar to narrow pseudopods of many protists but different in the following points: their origin from a unique organelle named the bothrosome, membrane invagination along EN, and absence of mitochondria and ribosomes. The bothrosome is located near the cell surface and is a complex ofthe electron dense material and the endoplasmic reticulum. Previously we observed, by immunofluorescence staining, that the actin filaments are located in EN. In this study, we investigated the process from a zoospore to a vegetative cell of Schizochytrium aggregatum, especially focusing on the development of the bothrosome and behavior of actin filaments. After the flagella were drawn into the cell, the bothrosome appeared de novo at the anterior-ventral region of the cell. After the zoospore settled and rounded, the actin appeared as a spot in the same position of the newly appeared bothrosome by immunofluorescence staining. It was expected that the electron dense material of the bothrosome is the organizing center of the actin filaments. However, under immunoelectron microscopy, reaction by the anti-actin antibody was observed in EN and cytoplasm around the bothrosome, not in the electron dense material of the bothrosome. It was suggested that the function of the bothrosome is not nucleation of actin filaments. We expect that actin relates to morphogenesis of EN, that is, the actin filaments probably play an important role ofpulling
the endoplasmic reticulum to the bothrosome and stretching the membrane invagination along EN.
MULTIGENE PHYLOGENY OF SYNURA (SYNUROPHYCEAE) AND DESCRIPTIONS OF FOUR NEW SPECIES BASED ON MORPHOLOGICAL AND DNA EVIDENCE Jo B.Y.1, Kim J.I.1, Skaloud P.2, Siver P.A.3, Shin W.1
1 - Department of Biology, Chungnam National University, Daejeon 305-764, Korea
2 - Department ofBotany, Faculty ofScience, Charles University, Benatska 2, Prague 2, CZ-12801, Czech Republic
3 - Department ofBotany, Connecticut College, New London, Connecticut 06320, USA shinw@cnu.ac.kr
We used phylogenetic analyses based on multiple gene sequences (partial nr SSU and LSU rDNA, partial pt LSU rDNA, psaA, and rbcL) from 148 strains (including three outgroups) and scale ultrastructure to examine phylogenetic relationships among species of the colonial genera Synura and Tessellaria. The phylogenetic tree based on the combined dataset was congruent with ultrastructural characteristics of the scales. Synura was divided into three major clades, two including species in section Synura, and one representing section Peterseniae. One clade, consisting of seven strains of S. uvella (section Synura), diverged at the base of the genus. The second clade consisted of the remaining species belonging to the section Synura. The third clade, containing organisms in the section Peterseniae and characterized by scales possessing a keel, was monophyletic with strong support values. Based on our findings, S. uvella needs to be in a separate section from other spine-bearing species, and we therefore propose new sectional ranks; Synura, Peterseniae, Curtispinae (presence of body scales with slender spines, tubular scales, and caudal scales). We further propose four new species based on phylogenetic analyses and unique scale characters; S. longitubularis sp. nov., S. sungminbooi sp. nov., S. soroconopea sp. nov., and S. lanceolata sp. nov.
CORRELATION BETWEEN FRESH WATER
CILIATED PROTIST COMMUNITIES AND
THEIR MICRO-ECOLOGY
Kamra Komal1, Kaur Harpreet1, Tripathi Charu2,
Kaur Surinder1, Narula Laxmi1, Lal Rup2, Warren
Alan3
1 - Ciliate Biology Lab, SGTB Khalsa College, University of Delhi, Delhi 110007
2 - Department of Zoology, University of Delhi, Delhi
