Researcher Information

NAKADA Takashi


Microscoping differences of microalgae

Department of Biological Sciences, Biodiversity


Taxonomic studies toward phylogenetic classification of microalgae

FieldPhycology, Phylogenetics, Taxonomy, Evolutionary biology, Morphology, Nomenclature
KeywordChlorophyceae, Volvocales, Chlamydomonas, Culture strains, Microscopy, Molecular phylogeny, International Code of Nomenclature for algae, fungi, and plants

Introduction of Research

Worlds of micro-organisms are as far as space and deep-see for human beings. Various invisibly small organisms live in water, and many of them are new species or insufficiently studied.

Among such microbes, I focuses on Volvocales (Chlorophyceae). Volvovales includes algae with various morphology. Most live in freshwater, but some live in the sea or even in snow. Most are unicellular, but some colony-forming. They are the "museum of cellular evolution", as they show various kinds of evolution at the cellular level.

However, there are many new species, species not known in Japan, species without recent records, even in neighboring ponds and soils. Their classification is also problematic.

Recently, molecular phylogenetic analyses revealed problems in traditional taxonomy and rebuilding new classification systems, but molecular sequence does not illustrate actual picture of each organism. Thus, we should cultivate and observe microalgae, and study even physiology of each species.
Uniting these knowledge, we can improve taxonomy of microalgae.

In this laboratory, morphology, cultivation, and physiology of Volvocales are studied.
- Establishing new strains, and describing new and poorly known species.
- Research on species differentiation.
- Examining less-used characteristics such as physiology.
- Reconstructing classification of Volvocales, satisfying both morphological and phylogenetical criteria.

I am also interested in the "names", both scientific and Japanese names, and their nomenclature.

Chlamydomonas reinhardtii, a unicellular volvocalean alga. Scale: 5 µm.
Volvox aureus, a colonial volvocalean alga. Scale: 300 µm.
Hapalochloris nozakii, a cell-wall less volvocalean alga, described as a new genus and species. Scale: 10 µm.

Representative Achievements

Nakada, T., Tsuchida, Y. & Tomita, M. Improved taxon sampling and multigene phylogeny of unicellular chlamydomonads closely related to the colonial volvocalean lineage Tetrabaenaceae-Goniaceae-Volvocaceae (Volvocales, Chlorophyceae). Mol. Phylogenet. Evol. 130, 1–8 (2019).
Nakada, T. & Tomita, M. Morphology and phylogeny of a new wall-less freshwater volvocalean flagellate, Hapalochloris nozakii gen. et sp. nov. (Volvocales, Chlorophyceae). J. Phycol. 53, 108–117 (2017).
Nakada, T., Tomita, M., Wu, J.-T. & Nozaki, H. Taxonomic revision of Chlamydomonas subg. Amphichloris (Volvocales, Chlorophyceae), with resurrection of the genus Dangeardinia and descriptions of Ixipapillifera gen. nov. and Rhysamphichloris gen. nov. J. Phycol. 52, 283–304 (2016).
Nakada, T., Misawa, K. & Nozaki, H. Molecular systematics of Volvocales (Chlorophyceae, Chlorophyta) based on exhaustive 18S rRNA phylogenetic analyses. Mol. Phylogenet. Evol. 48, 281–291 (2008).
Nakada, T., Nozaki, H. & Pröschold, T. Molecular phylogeny, ultrastructure and taxonomic revision of Chlorogonium (Chlorophyta): Emendation of Chlorogonium Ehrenberg and description of Gungnir gen. nov. and Rusalka gen. nov. J. Phycol. 44, 751–760 (2008).
Self Introduction

A bibliophile. If you are interested in microalgae, please visit my laboratory.

Affiliated academic societyThe Japanese Society of Phycology, The Japanese Society for Plant Systematics, The Botanical Society of Japan, Phycological Society of America, International Association for Plant Taxonomy
Room addressScience Building 5, 5-609

Department of Biological Sciences, Biodiversity

NAKADA Takashi


What made you decide to become a researcher?

In my childhood, I loved illustrated encyclopedias of several groups of organisms, which my grandparents bough for me. Naturally, my dream was to discover and name new species.

At first, I loved dinosaurs, and then, mammals, fishes, and plants (getting smaller and smaller). I collected ferns and mosses in the middle and high school, and mycomycetes (slime molds) in the undergraduate school. Finally, I decided to study microalgae in the graduate school. I must be studying prokaryotes in my next life.

What do you usually do when you get stuck in your research?

Even if an experiment doesn’t go well, I will keep trying. However, if it is so tiring, I may start another research in parallel, or writing a manuscript on a research. Once, I wrote a reviewing paper on prokaryotic nomenclature, when I was fed up with research.

Please tell us about yourself; things you are good at, your favorites, hobbies, and daily routines.

My hobby is collecting books. However, most of the books are waiting to be read. In addition to thousands of comic books and novels, I have books on taxa of most organisms. Books in a series are problematic, as they request me to purchase a complete set.

As a result of unpacking the moving luggage

In recent years, I have intensively collected dictionaries. Not only recent dictionaries, but also dictionaries in the Edo period. I am surveying when and how each algal name first appeared in dictionaries.

Home library (dictionary shelves) and Mr. Sapio