International Marine Biology Course in Asamushi, June 18-25, 2015

Introduction of Marine Invertebrates as tools for studies on oocyte maturation, fertilization and early development

Organized by Research Center for Marine Biology, Asamushi, Tohoku University


About the Course

Marine Invertebrates have been good model systems for analyzing fertilization and related events such as embryogenesis since late 19th century. They have been particularly popular as gametes are easy to obtain and handle, and embryos can be obtained easily via in vitro fertilization. In our course, we provide a wonderful opportunity for students in college and the early phase of graduate school to learn basic biology on multiple marine organisms such as ascidian, sea urchin, and jellyfish in the field of oocyte maturation through fertilization and embryogenesis. Instructors and lecturers are the experts and prominent researchers of the field. Participants also have a chance to discuss about the latest information on the research with the introduction of new experimental techniques of the field. This may give you hints for further study on your subject with your organisms in general. We look forward to seeing you in next June in Asamushi.

Instructors:*Please click each instructor to his/her own homepage.

Dr. Evelyn Houliston, Villefranche-sur-mer Marine Station, France

Dr. Alex McDougall, Villefranche-sur-mer Marine Station, France

Dr. Gary Wessel, Brown University, USA


Dr. Stephen A. Stricker, University of New Mexico, USA

Dr. Luigia Santella, Stazione Zoologica, Anton Dohrn, Italy


This course will take place at the Asamushi Research Center for Marine Biology, Tohoku University.

Organizing Committee members

Keiichiro Kyozuka
Atsushi Sogabe
Noriyo Takeda
Gaku Kumano


Order of each session may be exchanged according to the condition of sea, animals or instructor's schedule.
June 18th in the afternoon


Lecture 1: Dr. S.A. Stricker
Title: Comparative biology of oocyte maturation and fertilization in marine invertebrates
Lecture 2: Dr. L. Santella
Title: Actin cytoskeleton in the control of maturation and fertilization of echinoderm eggs
Welcome party (BBQ)
June 19-20th session 1

Instructors: Dr. E. Houliston and Dr. N.Takeda
Title: Hydrozoan jellyfish development and life cycle.
June 21-22nd session 2

Instructor: Dr. G. Wessel
Title: Eggs, Echinoderms, and Mechanisms of Development
June 23-24th session 3

Instructor: Dr. Alex McDougall
Title: Cell biological methods for studying fertilization and early embryonic development in ascidians.
June 25th in the morning

Total discussion


Session 1: Hydrozoan jellyfish development and life cycle
Instructors: Dr. E. Houliston and Dr. N. Takeda
Cnidaria is a very large and diverse phylum whose species have many different morphologies, developmental strategies and life cycles. The impressive expansion of the Cnidaria during evolution occurred in parallel with the evolution and diversification of its sister taxon, the Bilateria, starting from a common ancestor whose genome already contained the main known families of developmental regulator genes. Within the Cnidaria, the Anthozoa (corals, sea anemones etc) all have a larval form and a polyp adult form in their life cycle, while the Medusozoa species (including jellyfish, hydra and siphonophores) can have larvae, medusae and/or polyp forms. Within the Medusozoa, the class Hydrozoa shows a particularly great diversity of forms, development and life cycles.
In this session the students will be introduced to these animals through collecting in the field as well as laboratory observations and experiments, focused on the biological mechanisms controlling life cycle transitions such as spawning, fertilisation, larval development and metamorphosis.

Session 2: Eggs, Echinoderms, and Mechanisms of Development
Instructor: Dr. G. Wessel
We will conduct experience-based, research approaches to explore oocyte growth, meiosis, and embryonic development in a variety of echinoderms. This important taxon of animals is rich in the Asamushi area and provides potential to meet a variety of research interests. Important paradigms of development will be examined in this module, and students will be given the training, tools, and guidance to cultivate unique projects. Analytical and experimental techniques integrated into the module include embryological manipulations, molecular operations, cell biology approaches, and microscopic and imaging technologies, using state-of-the-art instrumentation and methodology. Conceptual topics in this module include cell specification and differentiation, pattern formation, embryonic axis formation, morphogenesis, intercellular signaling, and transcriptional regulation. Students are exposed to a wide variety of embryonic systems during this course, and our broad coverage of metazoan phylogeny allows for the analyses of the developmental strategies that drive evolutionary change.

Session3: Cell biological methods for studying fertilization and early embryonic development in ascidians.
Instructor: Dr. A. McDougall
Ascidians are primitive marine chordates whose embryos develop rapidly in seawater – a swimming tadpole larva forms about 12 hours after fertilization composed of only ~2600 cells. In the laboratory class we shall observe some of the key features of early ascidian development from a cell biological perspective – ooplasmic segregation and meiotic maturation following fertilization, unequal cleavage of the germ cell lineage from the 8 to 64-cell stage, the invariant cleavage pattern together with the nomenclature system for naming every cell (blastomere) up to the gastrula stage, plus how cell cycle duration and the process of gastrulation are linked. We have developed many cell biological tools (fluorescent proteins to label microtubules, centrosomes, plasma membrane etc.) and methods (fluorescent probes) to study early embryonic development in ascidians. During the laboratory class we will extend these methods to Ascidiella aspersa, an ascidian species found in Japan, Europe, and the USA (east coast) that has transparent eggs/embryos that are perfect for microscopic observations coupled with cell biological methods. In addition, we will demonstrate how to microinject ascidian eggs with mRNA encoding fluorescent fusion proteins (GFP/Venus/mCherry) to study subcellular events during early embryogenesis.

Lecture 1: Comparative biology of oocyte maturation and fertilization in marine invertebrates
Lecturer: Dr. S.A. Stricker
Nearly all animals are invertebrates, and the vast majority of the approximately 35 extant phyla of animals are composed of invertebrates that live either exclusively or predominantly in marine habitats. Accordingly, comparative surveys of the first cell cycle in marine invertebrates can reveal a seemingly bewildering array of reproductive modes that have evolved throughout the animal kingdom. In order to help provide an introduction to such diversity, this lecture aims to describe a few common themes and distinguishing characteristics of oocyte maturation and fertilization in marine invertebrates. In particular, topics such as the state of oocyte maturation at the time of fertilization, the roles of intraoocytic cyclic nucleotides and kinases in re-initiating meiosis, and the general patterns of fertilization-induced calcium signals will be considered.

Lecture 2: Actin cytoskeleton in the control of maturation and fertilization of echinoderm eggs
Lecturer: Dr. L. Santella
For more than a hundred years, starfish and sea urchin eggs have been ideal model systems to explore the mechanisms of maturation, fertilization and embryonic development in the natural medium, seawater. They are big cells, with a quasi-transparent cytoplasm and a large nucleus, properties that facilitate experiments of microinjection of various fluorescent probes into sub cellular compartments. During the breeding season, the gonad of female starfish is full of a synchronized population of the oocytes arrested at the first prophase of meiosis which can be induced to re-initiate in vitro by 1-methyladenine, and the subsequent changes in the nucleus (germinal vesicle breakdown) and cytoplasm can be easily followed. Thus, starfish have been of great value in studying oocyte maturation. On the other hand, sea urchin eggs are fertilized after the completion of meiosis, and are suitable for the study of sperm-egg interaction, early events of egg activation, and embryonic development. We have found that the deregulation of the actin cytoskeleton induced by interfering with the components of actin-regulating pathways, had a profound impact on meiotic maturation, egg activation, and, particularly, on the intracellular Ca2+ responses, cortical granules exocytosis and monospermic egg entry.

Qualification and Registration


1. Please send an e-mail to the following address with your intention to participate in the course and your email address for our reply by May 1, 2015.
2. We will then send an application form with additional information about
the course, accommodations and so on.

e-mail address: asamushi(at)
Please change (at) to @.
Qualification and skill for the Course:

Graduate and undergraduate students from any Institute in the world, who major biology and related field or has an interest in biology, especially developmental biology and embryology. Experiences of handling marine animals are not necessary. Undergraduate students who want to study on the developmental biology with marine invertebrates at Asamushi center in near future are welcome.
Participation students:

Approximately 12 undergraduate and graduate students of any nationality in total

Dormitory with cafeteria in the Asamushi center is available in reasonable cost during the Course. Please see Dormitory for details.
Financial Support:

We have applied for some grants to help your attendance partially. However, when you have a chance to apply the financial support in your institute to attend the Course, we would encourage you to apply for it and are willing to help with your paper work.