A neuroligin-3 mutation implicated in autism increases inhibitory synaptic transmission in mice     

Tabuchi K  Blundell J  Etherton MR  Hammer RE  Liu X  Powell CM  Südhof TC 《Science (New York, N.Y.)》2007,318(5847):71-76

Autism spectrum disorders (ASDs) are characterized by impairments in social behaviors that are sometimes coupled to specialized cognitive abilities. A small percentage of ASD patients carry mutations in genes encoding neuroligins, which are postsynaptic cell-adhesion molecules. We introduced one of these mutations into mice: the Arg451-->Cys451 (R451C) substitution in neuroligin-3. R451C mutant mice showed impaired social interactions but enhanced spatial learning abilities. Unexpectedly, these behavioral changes were accompanied by an increase in inhibitory synaptic transmission with no apparent effect on excitatory synapses. Deletion of neuroligin-3, in contrast, did not cause such changes, indicating that the R451C substitution represents a gain-of-function mutation. These data suggest that increased inhibitory synaptic transmission may contribute to human ASDs and that the R451C knockin mice may be a useful model for studying autism-related behaviors.  相似文献   

Enhanced bonding of gold nanoparticles on oxidized TiO2(110)     

Matthey D  Wang JG  Wendt S  Matthiesen J  Schaub R  Laegsgaard E  Hammer B  Besenbacher F 《Science (New York, N.Y.)》2007,315(5819):1692-1696

We studied the nucleation of gold clusters on TiO2(110) surfaces in three different oxidation states by high-resolution scanning tunneling microscopy. The three TiO2(110) supports chosen were (i) reduced (having bridging oxygen vacancies), (ii) hydrated (having bridging hydroxyl groups), and (iii) oxidized (having oxygen adatoms). At room temperature, gold nanoclusters nucleate homogeneously on the terraces of the reduced and oxidized supports, whereas on the hydrated TiO2(110) surface, clusters form preferentially at the step edges. From interplay with density functional theory calculations, we identified two different gold-TiO2(110) adhesion mechanisms for the reduced and oxidized supports. The adhesion of gold clusters is strongest on the oxidized support, and the implications of this finding for catalytic applications are discussed.  相似文献   

A chicken transferrin gene in transgenic mice escapes X-chromosome inactivation   总被引：4，自引：0，他引：4  

M A Goldman  K R Stokes  R L Idzerda  G S McKnight  R E Hammer  R L Brinster  S M Gartler 《Science (New York, N.Y.)》1987,236(4801):593-595

Mammalian X-chromosome inactivation involves a coordinate shutting down of physically linked genes. Several proposed models require the presence of specific sequences near genes to permit the spread of inactivation into these regions. If such models are correct, one might predict that heterologous genes transferred onto the X chromosome might lack the appropriate signal sequences and therefore escape inactivation. To determine whether a foreign gene inserted into the X chromosome is subject to inactivation, transgenic mice harboring 11 copies of the complete, 17-kilobase chicken transferrin gene on the X chromosome were used. Male mice hemizygous for this insert were bred with females bearing Searle's translocation, an X-chromosome rearrangement that is always active in heterozygous females (the unrearranged X chromosome is inactive). Female offspring bearing the Searle's translocation and the chicken transferrin gene had the same amount of chicken transferrin messenger RNA in liver as did transgenic male mice or transgenic female mice lacking the Searle's chromosome. This result shows that the inserted gene is not subject to X-chromosome inactivation and suggests that the inactivation process cannot spread over 187 kilobases of DNA in the absence of specific signal sequences required for inactivation.  相似文献   

Diversity of alpha-fetoprotein gene expression in mice is generated by a combination of separate enhancer elements   总被引：74，自引：0，他引：74  

R E Hammer  R Krumlauf  S A Camper  R L Brinster  S M Tilghman 《Science (New York, N.Y.)》1987,235(4784):53-58

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Robin Pistorius. Scientists, Plants and Politics. A History of the Plant Genetic Resources Movement.     

K. Hammer 《Genetic Resources and Crop Evolution》1998,45(1):95-95

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RX850实时操作系统在高压共轨柴油机电控系统中的应用     

顾宗林  刘瑞祥  苏洪良 《农业装备与车辆工程》2009,(5)

以嵌入式实时操作系统RX850作为软件开发平台,不仅可以充分利用硬件资源,同时也满足电控系统所要求的实时性和可靠性.根据高压共轨柴油机的实际工作状况,将整个系统划分为转速计算、喷油量计算、喷油正时计算等11个不同任务.有效地提高了系统运行效率和性能.  相似文献