Bioscience

New Clue to Develop Drugs against the Impaired Brain Memory

On Dec. 16, 2009, the American Journal of Neuroscience online published the latest research result achieved by Xu Tianle Research Group, the Institute of Neuroscience, Shanghai Institutes for Biological Sciences, CAS, ”GABA Transporter-1 Activity Modulates Hippocampal Theta Oscillation and Theta Burst Stimulation-Induced Long-Term Potentiation”. The network oscillation and synaptic plasticity of brain are perceived as having a close relationship with the formation of learning and memory. GABA transporter is mainly responsible for recapture of GABA released by synapsis and control of extracellular GABA concentration. Under the instruction of Prof. Xu Tianle, postdoctoral researcher Gong Neng and his collaborators, by use of GAT1 knockout mice and GAT1 specific inhibitor No711, found that in the CA1 region of mouse hippocampus, GABA regulates the synaptic plasticity in the form of long-term potentiation (LTP) induced by theta burst stimulation (TBS) through action on its receptor GABA(A). Beside change in the network oscillation and synaptic plasticity, researchers also observed obvious impairment of the hippocampus-dependent spatial learning and memory capability in GAT1 knockout mice. This research further proved the important role of GABA and its receptor in rhythmic network oscillation (particularly theta oscillation), synaptic plasticity, learning, memory and other cognitive behaviors of brain. In addition, because inhibition of GABA(A) receptor can reverse the impaired hippocampal synaptic plasticity in GAT1 knockout mice, this research also provided a new clue for the development of effective drugs against brain cognition-related diseases with impaired learning and memory.

New Age Records of Angiosperm Fossil

The latest issue of the English edition of Acta Geologica Sinica reported a fossil of Jurassic angiosperm newly found by Dr. Wang Xin from the Nanjing Institute of Geology and Palaleontology, CAS and Dr. Wang Shijun from the Institute of Botany, CAS. This angiosperm was named Xingxueanthus with the name of the famous palaeobotanist Li Xingxue as its generic name and China as its specific name. Because Xingxueanthus was preserved as a carbonized compression, many valuable details about this plant have been preserved. It was found under optical microscope and electron microscope that Xingxueanthus is an “inflorescence” with more than 20 female units spirally arranged. Each female unit is situated in the axil of a bract. The female unit is composed of an ovule-container and a style-like projection at the top. The ovule-container is equivalent to the ovary in modern angiosperms, which has a vertical column bearing several spirally arranged ovules. The two researchers held the view that its structures are more comparable to those of angiosperms. A critical feature distinguishing angiosperms from gymnosperms is that their ovules are contained in the ovary, which is the feature presenting in Xingxueanthus. The most surprising thing is that Xingxueanthus has an independent central placenta. According to traditional concept, the conduplicate carpel of marginal placenta in magnoliophyta is most primitive and the independent central placenta represents an advanced status. Apparently, Xingxueanthus with an independent central placenta appearing in the Middle Jurassic period went against this evolution law, according to which Xingxueanthus should be a “wrong” fossil. Such conflict between theory and reality often indicates and results in the advancement of new theories.