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排序方式: 共有186条查询结果,搜索用时 265 毫秒
21.
Kalscheuer VM Freude K Musante L Jensen LR Yntema HG Gécz J Sefiani A Hoffmann K Moser B Haas S Gurok U Haesler S Aranda B Nshedjan A Tzschach A Hartmann N Roloff TC Shoichet S Hagens O Tao J Van Bokhoven H Turner G Chelly J Moraine C Fryns JP Nuber U Hoeltzenbein M Scharff C Scherthan H Lenzner S Hamel BC Schweiger S Ropers HH 《Nature genetics》2003,35(4):313-315
We found mutations in the gene PQBP1 in 5 of 29 families with nonsyndromic (MRX) and syndromic (MRXS) forms of X-linked mental retardation (XLMR). Clinical features in affected males include mental retardation, microcephaly, short stature, spastic paraplegia and midline defects. PQBP1 has previously been implicated in the pathogenesis of polyglutamine expansion diseases. Our findings link this gene to XLMR and shed more light on the pathogenesis of this common disorder. 相似文献
22.
23.
Stephan L. Hatch 《西北部美国博物学家》2011,40(3)
New distribution records are given for seven grass species now found in Arizona, New Mexico, and Texas. 相似文献
24.
Stephan L. Hatch 《西北部美国博物学家》2011,36(2)
An investigation was made of Elymus simplex to evaluate the current taxonomy and cytology. The study included herbarium specimens from Wyoming and Colorado and population samples from the type location in Wyoming. The most important taxonomic characters noted are: numbers of spikelets per node, lemma awn length, and habitat. The chromosome number of E. simplex is reported as 2 n =28. E. simplex is a distinct species and should not be confused with E. salina, from which it differs morphologically. 相似文献
25.
John T. Heiker Nora Klöting Peter Kovacs E. Bartholomeus Kuettner Norbert Sträter Stephan Schultz Matthias Kern Michael Stumvoll Matthias Blüher Annette G. Beck-Sickinger 《Cellular and molecular life sciences : CMLS》2013,70(14):2569-2583
The molecular target of the adipokine vaspin (visceral adipose tissue-derived serpin; serpinA12) and its mode of action are unknown. Here, we provide the vaspin crystal structure and identify human kallikrein 7 (hK7) as a first protease target of vaspin inhibited by classical serpin mechanism with high specificity in vitro. We detect vaspin–hK7 complexes in human plasma and find co-expression of both proteins in murine pancreatic β-cells. We further demonstrate that hK7 cleaves human insulin in the A- and B-chain. Vaspin treatment of isolated pancreatic islets leads to increased insulin concentration in the media upon glucose stimulation without influencing insulin secretion. By application of vaspin and generated inactive mutants, we find the significantly improved glucose tolerance in C57BL/6NTac and db/db mice treated with recombinant vaspin fully dependent on the vaspin serpin activity and not related to vaspin-mediated changes in insulin sensitivity as determined by euglycemic-hyperinsulinemic clamp studies. Improved glucose metabolism could be mediated by increased insulin plasma concentrations 150 min after a glucose challenge in db/db mice, supporting the hypothesis that vaspin may inhibit insulin degradation by hK7 in the circulation. In conclusion, we demonstrate the inhibitory serpin nature and the first protease target of the adipose tissue-derived serpin vaspin, and our findings suggest hK7 inhibition by vaspin as an underlying physiological mechanism for its compensatory actions on obesity-induced insulin resistance. 相似文献
26.
To identify components of the mammalian endoplasmic reticulum involved in the translocation of secretory proteins, crosslinking and reconstitution methods were combined. A multispanning abundant membrane glycoprotein was found which is in proximity to nascent chains early in translocation. In reconstituted proteoliposomes, this protein is stimulatory or required for the translocation of secretory proteins. 相似文献
27.
M P Ollier M A Auger-Buendia L Hartmann 《Comptes rendus des séances de l'Académie des sciences. Série D, Sciences naturelles》1979,289(2):189-192
An original immunological two-dimensional technique with two different gels permits the protein analysis of 80 S cytoplasmic ribosomal murine particles and of their 60 S and 40 S subunits. The diagrams isolate and characterize a definite number of specific polypeptidic structures from each ribosomal particle. 相似文献
28.
Hauber E van Gasselt S Ivanov B Werner S Head JW Neukum G Jaumann R Greeley R Mitchell KL Muller P;HRSC Co-Investigator Team 《Nature》2005,434(7031):356-361
The majority of volcanic products on Mars are thought to be mafic and effusive. Explosive eruptions of basic to ultrabasic chemistry are expected to be common, but evidence for them is rare and mostly confined to very old surface features. Here we present new image and topographic data from the High Resolution Stereo Camera that reveal previously unknown traces of an explosive eruption at 30 degrees N and 149 degrees E on the northwestern flank of the shield volcano Hecates Tholus. The eruption created a large, 10-km-diameter caldera approximately 350 million years ago. We interpret these observations to mean that large-scale explosive volcanism on Mars was not confined to the planet's early evolution. We also show that glacial deposits partly fill the caldera and an adjacent depression. Their age, derived from crater counts, is about 5 to 24 million years. Climate models predict that near-surface ice is not stable at mid-latitudes today, assuming a thermo-dynamic steady state. Therefore, the discovery of very young glacial features at Hecates Tholus suggests recent climate changes. We show that the absolute ages of these very recent glacial deposits correspond very well to a period of increased obliquity of the planet's rotational axis. 相似文献
29.
Evidence from the Mars Express High Resolution Stereo Camera for a frozen sea close to Mars' equator
Murray JB Muller JP Neukum G Werner SC van Gasselt S Hauber E Markiewicz WJ Head JW Foing BH Page D Mitchell KL Portyankina G;HRSC Co-Investigator Team 《Nature》2005,434(7031):352-356
It is thought that the Cerberus Fossae fissures on Mars were the source of both lava and water floods two to ten million years ago. Evidence for the resulting lava plains has been identified in eastern Elysium, but seas and lakes from these fissures and previous water flooding events were presumed to have evaporated and sublimed away. Here we present High Resolution Stereo Camera images from the European Space Agency Mars Express spacecraft that indicate that such lakes may still exist. We infer that the evidence is consistent with a frozen body of water, with surface pack-ice, around 5 degrees north latitude and 150 degrees east longitude in southern Elysium. The frozen lake measures about 800 x 900 km in lateral extent and may be up to 45 metres deep--similar in size and depth to the North Sea. From crater counts, we determined its age to be 5 +/- 2 million years old. If our interpretation is confirmed, this is a place that might preserve evidence of primitive life, if it has ever developed on Mars. 相似文献
30.
Mechanism underlying the sleep-dream cycle 总被引:2,自引:0,他引:2
E Hartmann 《Nature》1966,212(5062):648-650