Disruption of CREB function in brain leads to neurodegeneration

Control of cellular survival and proliferation is dependent on extracellular signals and is a prerequisite for ordered tissue development and maintenance. Activation of the cAMP responsive element binding protein (CREB) by phosphorylation has been implicated in the survival of mammalian cells. To define its roles in the mouse central nervous system, we disrupted Creb1 in brain of developing and adult mice using the Cre/loxP system. Mice with a Crem(-/-) background and lacking Creb in the central nervous system during development show extensive apoptosis of postmitotic neurons. By contrast, mice in which both Creb1 and Crem are disrupted in the postnatal forebrain show progressive neurodegeneration in the hippocampus and in the dorsolateral striatum. The striatal phenotype is reminiscent of Huntington disease and is consistent with the postulated role of CREB-mediated signaling in polyglutamine-triggered diseases.     

Microsoft C 与 MASM 混合编程的研究

讨论了Microsoft C语言中调用MASM 5．0汇编语言程序的方法，并针对一些易出现的问题，如程序接口部分的要求，C语言与汇编程序间参数的传递，寄存器的使用等，提出了解决办法．     

Prey localization by surface wave ray-tracing: fish track bugs like oceanographers track storms

Surface-feeding fish accurately determine direction and distance to the center of a concentric wave stimulus, even if only a single, short lasting wave train is presented. It has been suggested that one cue used by these fish to localize the wave center is the distance dependent frequency modulation of the initial part of a wave stimulus. Here we show how the distance information contained in the fractional frequency change of a capillary wave group can be decoded. We suggest that wave source localization in surface-feeding fish in part is based on a principal similar to that used by oceanographers to track storms by the frequency change of forerunners of swell.     

Prey localization by surface wave ray-tracing: Fish track bugs like oceanographers track storms

Summary Surface-feeding fish accurately determine direction and distance to the center of a concentric wave stimulus, even if only a single, short lasting wave train is presented^1,2. It has been suggested that one cue used by these fish to localize the wave center is the distance dependent frequency modulation of the initial part of a wave stimulus^3,4. Here we show how the distance information contained in the fractional frequency change of a capillary wave group can be decoded. We suggest that wave source localization in surface-feeding fish in part is based on a principal similar to that used by oceanographers to track storms by the frequency change of forerunners of swell.     

Reaction time of the topminnowAplocheilus lineatus to surface waves determined by video- and electromyogram recordings

Summary Evoked muscle potentials during a localizing response for a wave center occur inAplocheilus lineatus 30±1.5 msec ( ) earlier than the simultaneously monitored body movements. Considering this time, only the first 8–10 wave cycles of a total wave signal are utilized to identify and localize a wave source.This study was supported by the Deutsche Forschungsgemeinschaft.