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排序方式: 共有117条查询结果,搜索用时 31 毫秒
1.
Constance Mehlgarten Daniel Jablonowski Uta Wrackmeyer Susan Tschitschmann David Sondermann Gunilla Jäger Zhizhong Gong Anders S. Byström Raffael Schaffrath Karin D. Breunig 《Molecular microbiology》2010,76(5):1082-1094
Based on studies in yeast and mammalian cells the Elongator complex has been implicated in functions as diverse as histone acetylation, polarized protein trafficking and tRNA modification. Here we show that Arabidopsis mutants lacking the Elongator subunit AtELP3/ELO3 have a defect in tRNA wobble uridine modification. Moreover, we demonstrate that yeast elp3 and elp1 mutants expressing the respective Arabidopsis Elongator homologues AtELP3/ELO3 and AtELP1/ELO2 assemble integer Elongator complexes indicating a high degree of structural conservation. Surprisingly, in vivo complementation studies based on Elongator‐dependent tRNA nonsense suppression and zymocin tRNase toxin assays indicated that while AtELP1 rescued defects of a yeast elp1 mutant, the most conserved Elongator gene AtELP3, failed to complement an elp3 mutant. This lack of complementation is due to incompatibility with yeast ELP1 as coexpression of both plant genes in an elp1 elp3 yeast mutant restored Elongator's tRNA modification function in vivo. Similarly, AtELP1, not ScELP1 also supported partial complementation by yeast–plant Elp3 hybrids suggesting that AtElp1 has less stringent sequence requirements for Elp3 than ScElp1. We conclude that yeast and plant Elongator share tRNA modification roles and propose that this function might be conserved in Elongator from all eukaryotic kingdoms of life. 相似文献
2.
Philippe J. R. Kok Monique Hölting Raffael Ernst 《Organisms Diversity & Evolution》2013,13(4):621-638
The aromobatid frog Allobates amissibilis sp. nov. is described from a very limited area in the Iwokrama Mountains at elevations between 160 and 950 m, in central Guyana, South America. The new taxon is diagnosed from other Allobates species by morphology, bioacoustics, and genetics, and can be distinguished readily from known congeners by cryptic colouration, small size (16.3–17.8 mm snout-vent length), absence of distinct dorsal pattern in living adult individuals, presence of a distinctly enlarged tubercle on each eyelid, diffuse broad oblique lateral stripe extending from groin to about midbody length, sexually dimorphic throat colouration (pinkish grey, suffused with dark pigment in male, immaculate cream to yellow in female), belly cream to yellow in both sexes, and distinct vocalisation formed by calls of usually 9–12 notes emitted between silent intervals of usually ca. 2–6 s, with a dominant frequency ranging from 5,064 to 5,845 Hz. The new species is the third microendemic reported from the Iwokrama Mountains together with the caecilian Caecilita iwokramae and the lizard Gonatodes timidus. We recommend considering the conservation status of the new species as Data Deficient, and highlight that environmental impact assessments are needed to refine its IUCN threat status. 相似文献
3.
Learning to predict danger via associative learning processes is critical for adaptive behaviour. After successful extinction, persisting fear memories often emerge as returning fear. Investigation of return of fear phenomena, e.g. reinstatement, have only recently began and to date, many critical questions with respect to reinstatement in human populations remain unresolved. Few studies have separated experimental phases in time even though increasing evidence shows that allowing for passage of time (and consolidation) between experimental phases has a major impact on the results. In addition, studies have relied on a single psychophysiological dimension only (SCRs/SCL or FPS) which hampers comparability between different studies that showed both differential or generalized return of fear following a reinstatement manipulation. In 93 participants, we used a multimodal approach (fear-potentiated startle, skin conductance responses, fear ratings to asses fear conditioning (day 1), extinction (day 2) as well as delayed memory recall and reinstatement (day 8) in a paradigm that probed contextual and cued fear intra-individually. Our findings show persistence of conditioning and extinction memory over time and demonstrate that reinstated fear responses were qualitatively different between dependent variables (subjective fear ratings, FPS, SCRs) as well as between cued and contextual CSs. While only the arousal-related measurement (SCRs) showed increasing reactions following reinstatement to the cued CSs, no evidence of reinstatement was observed for the subjective ratings and fear-related measurement (FPS). In contrast, for contextual CSs, reinstatement was evident as differential and generalized reinstatement in fear ratings as well as generally elevated physiological fear (FPS) and arousal (SCRs) related measurements to all contextual CSs (generalized non-differential reinstatement). Returning fear after reinstatement likely depends on a variety of variables (experimental design, dependent measurements) and more systematic investigations with respect to critical determinants of reinstatement in humans are required. 相似文献
4.
5.
Sabrina I?igo Astrid Nagels Durand Andrés Ritter Sabine Le Gall Martin Termathe Roland Klassen Takayuki Tohge Barbara De Coninck Jelle Van Leene Rebecca De Clercq Bruno P.A. Cammue Alisdair R. Fernie Kris Gevaert Geert De Jaeger Sebastian A. Leidel Raffael Schaffrath Mieke Van Lijsebettens Laurens Pauwels Alain Goossens 《Plant physiology》2016,172(2):858-873
6.
Prevalence of endoparasitic mites on four West African leaf‐litter frogs depends on habitat humidity
Tokouaho Flora Kpan Raffael Ernst Philippe K. Kouassi Mark‐Oliver Rdel 《Biotropica》2019,51(3):432-442
Amphibian species are known to carry endoparasitic mites. The infestation probability, prevalence, and intensity of mites vary among species and habitats. Mites of the genus Endotrombicula are known to infest African and Malagasy frogs. However, the factors leading to an increase in the probability of mite infestation are unknown. To test for inter‐ and intraspecific differences in infestation probability and its potential correlation with sex, age, habitat preferences, and/or season within a species‐rich West African leaf‐litter frog assemblage, we examined more than 6,800 individual frogs for the presence of mites throughout two independent time increments, 1999–2000 and 2016–2017. We found only members of the leaf‐litter frog genus Phyrnobatrachus to be infested, while other syntopically occurring genera were not affected. Within Phrynobatrachus, only four out of eight species were infested. Mites prevalence differed between species (highest P. phyllophilus, followed by P. alleni), sex (males higher than females in P. alleni and P. phyllophilus), and age (adults higher than juveniles in P. alleni), as well as season (more mites during wet than dry season in P. phyllophilus). The prevalence of mite infestation did not influence mate choice in P. alleni. Increased humidity showed a clear positive effect on infestation prevalence. We also detected a marked decrease in the prevalence of mites from 1999–2000 to 2016–2017, a period during which climatological changes within the study area have been reported with a tendency toward drier conditions. The decrease in mite infestation prevalence over time might be a signal of increasingly drier conditions. 相似文献
7.
8.
Fichtner L Frohloff F Bürkner K Larsen M Breunig KD Schaffrath R 《Molecular microbiology》2002,43(3):783-791
TOT, the putative Kluyveromyces lactis zymocin target complex from Saccharomyces cerevisiae, is encoded by TOT1-7, six loci of which are isoallelic to RNA polymerase II (RNAPII) Elongator genes (ELP1-6). Unlike TOT1-3 (ELP1-3) and TOT5-7 (ELP5, ELP6 and ELP4 respectively), which display zymocin resistance when deleted, TOT4 (KTI12) also renders cells refractory to zymocin when maintained in multicopy or overexpressed from the GAL10 promoter. Elevated TOT4 copy number results in an intermediate tot phenotype, which includes mild sensitivities towards caffeine, Calcofluor white and elevated growth temperature, suggesting that TOT4 influences TOT/Elongator function. Tot4p interacts with Elongator, as shown by co-immunoprecipitation, and cell fractionation studies demonstrate partial co-migration with RNAPII and Elongator. As Elongator subunit interaction is not affected by either deletion of TOT4 or multicopy TOT4, Tot4p may not be a structural Elongator subunit but, rather, may regulate TOT/Elongator in a fashion that requires transient physical contact with TOT/Elongator. Consistent with a regulatory role, the presence of a potential P-loop motif conserved between yeast and human TOT4 homologues suggests capability of ATP or GTP binding and P-loop deletion renders Tot4p biologically inactive. 相似文献
9.
Roland Klassen Pia Grunewald Kathrin L. Thüring Christian Eichler Mark Helm Raffael Schaffrath 《PloS one》2015,10(3)
In eukaryotes, wobble uridines in the anticodons of tRNALys
UUU, tRNAGlu
UUC and tRNAGln
UUG are modified to 5-methoxy-carbonyl-methyl-2-thio-uridine (mcm5s2U). While mutations in subunits of the Elongator complex (Elp1-Elp6), which disable mcm5 side chain formation, or removal of components of the thiolation pathway (Ncs2/Ncs6, Urm1, Uba4) are individually tolerated, the combination of both modification defects has been reported to have lethal effects on Saccharomyces cerevisiae. Contrary to such absolute requirement of mcm5s2U for viability, we demonstrate here that in the S. cerevisiae S288C-derived background, both pathways can be simultaneously inactivated, resulting in combined loss of tRNA anticodon modifications (mcm5U and s2U) without a lethal effect. However, an elp3 disruption strain displays synthetic sick interaction and synergistic temperature sensitivity when combined with either uba4 or urm1 mutations, suggesting major translational defects in the absence of mcm5s2U modifications. Consistent with this notion, we find cellular protein levels drastically decreased in an elp3uba4 double mutant and show that this effect as well as growth phenotypes can be partially rescued by excess of tRNALys
UUU. These results may indicate a global translational or protein homeostasis defect in cells simultaneously lacking mcm5 and s2 wobble uridine modification that could account for growth impairment and mainly originates from tRNALys
UUU hypomodification and malfunction. 相似文献
10.
Diet and exercise improve chemoreflex sensitivity in patients with metabolic syndrome and obstructive sleep apnea
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Cristiane Maki‐Nunes Edgar Toschi‐Dias Felipe X. Cepeda Maria Urbana P.B. Rondon Maria‐Janieire N. N. Alves Raffael F. Fraga Ana Maria F. W. Braga Adriana M. Aguilar Aline C. Amaro Luciano F. Drager Geraldo Lorenzi‐Filho Carlos E. Negrão Ivani C. Trombetta 《Obesity (Silver Spring, Md.)》2015,23(8):1582-1590