***** seminarMLから情報転載 *****

英国MRCのMario de Bono博士が来日される機会にセミナーをお願いしました。線虫の「社会性行動」の研究で有名で、この機構の研究を常に最先端に立って進められています。さらにこれと関連して酸素と二酸化炭素のセンシング機構を重点的に調べられており、グアニル酸シクラーゼとニューログロビンが酸素センサーであることを見つけています。ぜひお誘い合わせの上、お越し頂ければ幸いです。

東京大学大学院理学系研究科生物化学専攻 飯野雄一



講師:Mario de Bono (MRC Laboratory of Molecular Biology&s_comma; Cambridge&s_comma; England)
演題:Aggregating in rotten places: oxygen and carbon dioxid sensing in C. elegans.

Behaviour arises from the interplay between the environment&s_comma; experience and
dynamic network of genes&s_comma; neurons and neural circuits. We are studying how such
networks encode and modulat behaviour&s_comma; using C. elegans as a model. In this
animal we can dissect neural networks into individual identified neurons since
the C. elegans nervous system has exactly 302 neurons&s_comma; all recognizable&s_comma; and
these have reproducible functions and synaptic connections. Using powerful
genetics we can also elucidate the molecular pathways underpinning neural function.

Foraging in C. elegans involves integration of multiple sensory cues&s_comma; including
signals from bacterial food&s_comma; other animals&s_comma; gases and internal nutritional
state. Two important regulators of foraging are ambient oxygen and carbon
dioxide. C. elegans uses distributed neural circuits to sense and respond to
each of these gases. Two types of O2 sensing molecules are soluble guanylate
cyclases and globins. These sensors act together to shape the O2 response of C.
elegans into a sharp sigmoidal curve tuned close to 21% - the concentration of
O2 at earth’s surface. O2 responses serve both to help worms escape the surface
and to find food. CO2 sensors help prevent animals getting trapped in high CO2
environments. Both O2 and CO2 sensing neurons continue signaling as long as
their cognate stimulus is present. Chronic signaling by these neurons appears to
set the animal into different behavioural states&s_comma; analogous to moods.

O2&s_comma; CO2&s_comma; food and other animals regulate a higher-order behaviour of C. elegans&s_comma;
aggregation. I will describe the behavioural responses that allow animals to
aggregate together and the neural circuits underlying them. One mechanism
involves use head and tail sensors that allow animals to detect if they are
moving forwards or backwards out of a group.