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61.
Sequence and expression of transcripts of the human T-cell receptor beta-chain genes 总被引:1,自引:0,他引:1
Y Yoshikai D Anatoniou S P Clark Y Yanagi R Sangster P Van den Elsen C Terhorst T W Mak 《Nature》1984,312(5994):521-524
62.
Light-inducible and chloroplast-associated expression of a chimaeric gene introduced into Nicotiana tabacum using a Ti plasmid vector 总被引:40,自引:0,他引:40
L Herrera-Estrella G Van den Broeck R Maenhaut M Van Montagu J Schell M Timko A Cashmore 《Nature》1984,310(5973):115-120
A chimaeric gene, consisting of the 5'-flanking region of a member of the Pisum sativum gene family encoding ribulose 1,5-bisphosphate carboxylase linked to the coding region of a bacterial chloramphenicol acetyltransferase gene, has been introduced into the genome of the plant Nicotiana tabacum using a Ti plasmid of Agrobacterium tumefaciens. The expression of the chimaeric gene is light-inducible in chloroplast-containing transformed tissue. 相似文献
63.
Miscunica Platica W. Harding V. P. Hollander 《Cellular and molecular life sciences : CMLS》1978,34(9):1154-1155
Summary Dithiothreitol, dithioerythritol and bacterial lipopolysaccharides increase optical absorbance and clotLimulus lysate. Purification of dithiothreitol from possible endotoxin contamination by vacuum sublimation or chromatography does not abolish the reaction with lysate. The dithiols reported active here represent the smallest molecules capable of simulating endotoxin in theLimulus test.Acknowledgments. This investigation was supported by grant No. P30 14194 and CA 12635, awarded by the National Cancer Institute, Dhew. 相似文献
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65.
Résumé Le mutant homozygote d'Ambystoma mexicanum qui n'a pas d'activité cardiaque myogénique, est aussi réfractaire aux modifications chimiques et électriques des potentiels membranaires et de la fréquence cardiaque. Il diffère en cela de l'animal normal au même stage de developpement embryonnaire.
Supported in part by the Arizona Heart Association, the Central Ohio Heart Association, and by the National Institutes of Health No. HE 09567.
Established investigatorship of the American Heart Association.
Supported by U.S. Public Health Service Career Development award No. HE 11,929. 相似文献
Supported in part by the Arizona Heart Association, the Central Ohio Heart Association, and by the National Institutes of Health No. HE 09567.
Established investigatorship of the American Heart Association.
Supported by U.S. Public Health Service Career Development award No. HE 11,929. 相似文献
66.
Vonk FJ Admiraal JF Jackson K Reshef R de Bakker MA Vanderschoot K van den Berge I van Atten M Burgerhout E Beck A Mirtschin PJ Kochva E Witte F Fry BG Woods AE Richardson MK 《Nature》2008,454(7204):630-633
Many advanced snakes use fangs-specialized teeth associated with a venom gland-to introduce venom into prey or attacker. Various front- and rear-fanged groups are recognized, according to whether their fangs are positioned anterior (for example cobras and vipers) or posterior (for example grass snakes) in the upper jaw. A fundamental controversy in snake evolution is whether or not front and rear fangs share the same evolutionary and developmental origin. Resolving this controversy could identify a major evolutionary transition underlying the massive radiation of advanced snakes, and the associated developmental events. Here we examine this issue by visualizing the tooth-forming epithelium in the upper jaw of 96 snake embryos, covering eight species. We use the sonic hedgehog gene as a marker, and three-dimensionally reconstruct the development in 41 of the embryos. We show that front fangs develop from the posterior end of the upper jaw, and are strikingly similar in morphogenesis to rear fangs. This is consistent with their being homologous. In front-fanged snakes, the anterior part of the upper jaw lacks sonic hedgehog expression, and ontogenetic allometry displaces the fang from its posterior developmental origin to its adult front position-consistent with an ancestral posterior position of the front fang. In rear-fanged snakes, the fangs develop from an independent posterior dental lamina and retain their posterior position. In light of our findings, we put forward a new model for the evolution of snake fangs: a posterior subregion of the tooth-forming epithelium became developmentally uncoupled from the remaining dentition, which allowed the posterior teeth to evolve independently and in close association with the venom gland, becoming highly modified in different lineages. This developmental event could have facilitated the massive radiation of advanced snakes in the Cenozoic era, resulting in the spectacular diversity of snakes seen today. 相似文献
67.
Gaspard N Bouschet T Hourez R Dimidschstein J Naeije G van den Ameele J Espuny-Camacho I Herpoel A Passante L Schiffmann SN Gaillard A Vanderhaeghen P 《Nature》2008,455(7211):351-357
The cerebral cortex develops through the coordinated generation of dozens of neuronal subtypes, but the mechanisms involved remain unclear. Here we show that mouse embryonic stem cells, cultured without any morphogen but in the presence of a sonic hedgehog inhibitor, recapitulate in vitro the major milestones of cortical development, leading to the sequential generation of a diverse repertoire of neurons that display most salient features of genuine cortical pyramidal neurons. When grafted into the cerebral cortex, these neurons develop patterns of axonal projections corresponding to a wide range of cortical layers, but also to highly specific cortical areas, in particular visual and limbic areas, thereby demonstrating that the identity of a cortical area can be specified without any influence from the brain. The discovery of intrinsic corticogenesis sheds new light on the mechanisms of neuronal specification, and opens new avenues for the modelling and treatment of brain diseases. 相似文献
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69.
Kuijl C Savage ND Marsman M Tuin AW Janssen L Egan DA Ketema M van den Nieuwendijk R van den Eeden SJ Geluk A Poot A van der Marel G Beijersbergen RL Overkleeft H Ottenhoff TH Neefjes J 《Nature》2007,450(7170):725-730
With the emergence of multidrug resistant (MDR) bacteria, it is imperative to develop new intervention strategies. Current antibiotics typically target pathogen rather than host-specific biochemical pathways. Here we have developed kinase inhibitors that prevent intracellular growth of unrelated pathogens such as Salmonella typhimurium and Mycobacterium tuberculosis. An RNA interference screen of the human kinome using automated microscopy revealed several host kinases capable of inhibiting intracellular growth of S. typhimurium. The kinases identified clustered in one network around AKT1 (also known as PKB). Inhibitors of AKT1 prevent intracellular growth of various bacteria including MDR-M. tuberculosis. AKT1 is activated by the S. typhimurium effector SopB, which promotes intracellular survival by controlling actin dynamics through PAK4, and phagosome-lysosome fusion through the AS160 (also known as TBC1D4)-RAB14 pathway. AKT1 inhibitors counteract the bacterial manipulation of host signalling processes, thus controlling intracellular growth of bacteria. By using a reciprocal chemical genetics approach, we identified kinase inhibitors with antibiotic properties and their host targets, and we determined host signalling networks that are activated by intracellular bacteria for survival. 相似文献
70.