ANAPHASE PROMOTING COMPLEX/CYCLOSOME-mediated cyclin B1 degradation is critical for cell cycle synchronization in syncytial endosperms

Although it is known that in most angiosperms mitosis in early endosperm development is syncytial and synchronized, it is unclear how the synchronization is regulated. We showed previously that APC11, also named ZYGI, in Arabidopsis activates zygote division by interaction and degradation of cyclin B1. Here, we report that the mutation in APC11/ZYG1 led to unsynchronized mitosis and over-accumulation of cyclin B1-GUS in the endosperm. Mutations in two other APC subunits showed similar defects. Transgenic expression of stable cyclin B1 in the endosperm also caused unsynchronized mitosis. Further, downregulation of APC11 generated multi-nucleate somatic cells with unsynchronized mitotic division. Together, our results suggest that APC/C-mediated cyclin B1 degradation is critical for cell cycle synchronization.

System integration of China's first PEMFC locomotive

In the face of growing environmental pollution, developing a fuel-cell-driven shunting locomotive is a great challenge in China for environmental protection and energy saving, which combines the environmental advantages of an electric locomotive with the lower infrastructure costs of a diesel-electric locomotive. In this paper, the investigation status and the development trend of the fuel-cell-driven shunting locomotive were introduced. Through innovation of the power system using fuel cells, an experiment prototype of a fuel-cell shunting locomotive was developed, which would reduce the effects on the environment of the existing locomotives. This was the first locomotive to use a proton exchange membrane fuel-cell （PEMFC） power plant in China. From October 2012, we started to test the fuel-cell power plant and further test runs on the test rail-line in Chengdu, Sichuan. The achieved encouraging results can provide fundamental data for the modification of the current individual fuel cell locomotives or further development of the fuel-cell hybrid ones in China.

Stimulus discrimination via responses of retinal ganglion cells and dopamine-dependent modulation

Neighboring retinal ganglion cells（RGCs）fire with a high degree of correlation.It has been increasingly realized that visual perception of the environment relies on neuronal population activity to encode and transmit the information contained in stimuli.Understanding how neuronal population activity contributes to visual information processing is essential for understanding the mechanisms of visual coding.Here we simultaneously recorded spike discharges from groups of RGCs in bullfrog retina in response to visual patterns（checkerboard,horizontal grating,and full-field illumination）using a multi-electrode array system.To determine the role of synchronous activity mediated by gap junctions,we measured the correct classification rates of single cells＇firing patterns as well as the synchronization patterns of multiple neurons.We found that,under normal conditions,RGC population activity exhibited distinct response features with exposure to different stimulus patterns and had a higher rate of correct stimulus discrimination than the activity of single cells.Dopamine（1μmol/L）application did not significantly change the performance of single neuron activity,but enhanced the synchronization of the RGC population activity and decreased the rate of correct stimulus pattern discrimination.These findings suggest that the synchronous activity of RGCs plays an important role in the information coding of different types of visual patterns,and a dopamine-induced increase in synchronous activity weakens the population performance in pattern discrimination,indicating the potential role of the dopaminergic pathway in modulating the population coding process.