|専攻分野||Developmental biology, Reproductive Biology|
Oocytes and sperm are single cells that do not maintain their activity as a single cell for long. I am interested in how these cells prolong their lives by successful fertilization. Gametes from marine invertebrates have excellent characteristics for the study of oocyte maturation and fertilization. I plan to introduce the benefits of these organisms as experimental materials in my lectures and marine biology courses.
Intracellular calcium signaling in the fertilized eggs of Annelida.
Mitochondrial activation and nitric oxide (NO) release at fertilization in echinoderm eggs.
Guanine nucleotides in the meiotic maturation of starfish oocytes: regulation of the actin cytoskeleton and of Ca(2+) signaling.
Nitric oxide (NO) increase at fertilization in sea urchin eggs upregulates fertilization envelope hardening.
Actin cytoskeleton modulates calcium signaling during maturation of starfish oocytes.
Novel two-step Ca2+ increase and its mechanisms and functions at fertilization in oocytes of the annelidan worm Pseudopotamilla occelata.
Two phases of calcium requirement during starfish meiotic maturation.
Serotonin stimulates [Ca2+]i elevation in ciliary ectodermal cells of echinoplutei through a serotonin receptor cell network in the blastocoel.
Japanese Society of Developmental Biologists
Marine Biology and PracticeII (Faculty of Science)
Intracellular Ca2+ changes during fertilization in the ascidian, Ciona savignyi
We study the mechanism of oocyte maturation and fertilization, using ascidians, echinoderms, mollusks, annelids, and jellyfish as experimental models. Our research projects are categorized in three primary topics, which are: 1) how an oocyte obtains the ability for the re-initiation of meiosis and further development by the spermatozoon; 2) how the fertilizing spermatozoon enters the oocyte; and 3) how the fertilizing spermatozoon activates the oocyte.
During re-initiation of oocyte maturation by maturation inducing hormones and the activation of the oocyte at fertilization by the spermatozoon, the increase in intracellular Ca2+ plays an important role. In most cases, artificial induction of Ca2+ increase in the oocyte is sufficient to trigger the re-initiation of meiosis and egg action in many species. Therefore, we are going to clarify how Ca2+ is involved in those events.
Our laboratory is located far from the main campuses in Sendai, but Mutsu Bay around our Institute offers an abundance of nature and marine organisms. We can collect and work with a variety of interesting animals such as cnidarians (left), annelids, and mollusks (right) as shown in the pictures below, and more.
Asuka Komatsu (M2)
Miyagi University of Education
Mechanism of spermatogenesis and spawning in jellyfish, Cladonema pacificum.
Isao Takahashi (D3)
Nagahama Institute of Bio-Science and Technology,
Study for the Ca2+ increase in the oocyte during fertilization in starfish, Asterina pectinifera.