Proceedings of the Japan Academy, Series B
Online ISSN : 1349-2896
Print ISSN : 0386-2208
ISSN-L : 0386-2208
Volume 89, Issue 5
Displaying 1-3 of 3 articles from this issue
  • Fumihiko SATO, Hidehiko KUMAGAI
    2013 Volume 89 Issue 5 Pages 165-182
    Published: May 10, 2013
    Released on J-STAGE: May 10, 2013
    Plants produce a variety of secondary metabolites that possess strong physiological activities. Unfortunately, however, their production can suffer from a variety of serious problems, including low levels of productivity and heterogeneous quality, as well as difficulty in raw material supply. In contrast, microorganisms can be used to produce their primary and some of their secondary metabolites in a controlled environment, thus assuring high levels of efficiency and uniform quality. In an attempt to overcome the problems associated with secondary metabolite production in plants, we developed a microbial platform for the production of plant isoquinoline alkaloids involving the unification of the microbial and plant metabolic pathways into a single system. The potential applications of this system have also been discussed.

    (Communicated by Koichiro TSUNEWAKI, M.J.A.)
    Download PDF (1279K)
  • Tomoo HIRANO
    2013 Volume 89 Issue 5 Pages 183-195
    Published: May 10, 2013
    Released on J-STAGE: May 10, 2013
    Cerebellar long-term depression (LTD) is a type of synaptic plasticity and has been considered as a critical cellular mechanism for motor learning. LTD occurs at excitatory synapses between parallel fibers and a Purkinje cell in the cerebellar cortex, and is expressed as reduced responsiveness to transmitter glutamate. Molecular induction mechanism of LTD has been intensively studied using culture and slice preparations, which has revealed critical roles of Ca2+, protein kinase C and endocytosis of AMPA-type glutamate receptors. Involvement of a large number of additional molecules has also been demonstrated, and their interactions relevant to LTD mechanisms have been studied. In vivo experiments including those on mutant mice, have reported good correlation of LTD and motor learning. However, motor learning could occur with impaired LTD. A possibility that cerebellar synaptic plasticity other than LTD compensates for the defective LTD has been proposed.

    (Communicated by Masao ITO, M.J.A.)
    Download PDF (437K)
Original Article