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排序方式: 共有217条查询结果,搜索用时 15 毫秒
61.
62.
Peter L. Falkingham Karl T. Bates Marco Avanzini Matthew Bennett Emese M. Bordy Brent H. Breithaupt Diego Castanera Paolo Citton Ignacio Díaz‐Martínez Jim O. Farlow Anthony R. Fiorillo Stephen M. Gatesy Patrick Getty Kevin G. Hatala Jahn J. Hornung James A. Hyatt Hendrik Klein Jens N. Lallensack Anthony J. Martin Daniel Marty Neffra A. Matthews Christian A. Meyer Jesper Milàn Nicholas J. Minter Novella L. Razzolini Anthony Romilio Steven W. Salisbury Lara Sciscio Ikuko Tanaka Ashleigh L. A. Wiseman L. D. Xing Matteo Belvedere 《Palaeontology》2018,61(4):469-480
The collection and dissemination of vertebrate ichnological data is struggling to keep up with techniques that are becoming commonplace in the wider palaeontological field. A standard protocol is required to ensure that data is recorded, presented and archived in a manner that will be useful both to contemporary researchers, and to future generations. Primarily, our aim is to make the 3D capture of ichnological data standard practice, and to provide guidance on how such 3D data can be communicated effectively (both via the literature and other means) and archived openly and in perpetuity. We recommend capture of 3D data, and the presentation of said data in the form of photographs, false‐colour images, and interpretive drawings. Raw data (3D models of traces) should always be provided in a form usable by other researchers (i.e. in an open format). If adopted by the field as a whole, the result will be a more robust and uniform literature, supplemented by unparalleled availability of datasets for future workers. 相似文献
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Motz C Hornung T Kersten M McLachlin DT Dunn SD Wise JG Vogel PD 《The Journal of biological chemistry》2004,279(47):49074-49081
We have used site-specific spin-labeling of single cysteine mutations within a water-soluble mutant of subunit b of the ATP synthase and employed electron spin resonance (ESR) spectroscopy to obtain information about the binding interactions of the b dimer with F1-ATPase. Interaction of b2 with a delta-depleted F1 (F1-delta) was also studied. The cysteine mutations used for spin-labeling were distributed throughout the cytosolic domain of the b subunit. In addition, each position between residues 101 and 114 of b was individually mutated to cysteine. All mutants were modified with a cysteine-reactive spin label. The room temperature ESR spectra of spin-labeled b2 in the presence of F1 or F1-delta when compared with the spectra of free b2 indicate a tight binding interaction between b2 and F1. The data suggest that b2 packs tightly to F1 between residues 80 and the C terminus but that there are segments of b2 within that region where packing interactions are quite loose. Two-dimensional gel electrophoresis confirmed binding of the modified b mutants to F1-ATPase as well as to F1-delta. Subsequent addition of delta to F1-delta.b2 complex resulted in changes in the ESR spectra, indicating different binding interactions of b to F1 in the presence or absence of delta. The data also suggest that the reconstitution of the ATP synthase is not ordered with respect to these subunits. Additional spectral components observed in b preparations that were spin-labeled between amino acid position 101 and 114 are indicative of either two populations of b subunits with different packing interactions or to helical bending within this region. 相似文献
65.
Mathieu Niquille Sonia Garel Fanny Mann Jean-Pierre Hornung Belkacem Otsmane Sébastien Chevalley Carlos Parras Francois Guillemot Patricia Gaspar Yuchio Yanagawa Cécile Lebrand 《PLoS biology》2009,7(10)
The corpus callosum (CC) is the main pathway responsible for interhemispheric communication. CC agenesis is associated with numerous human pathologies, suggesting that a range of developmental defects can result in abnormalities in this structure. Midline glial cells are known to play a role in CC development, but we here show that two transient populations of midline neurons also make major contributions to the formation of this commissure. We report that these two neuronal populations enter the CC midline prior to the arrival of callosal pioneer axons. Using a combination of mutant analysis and in vitro assays, we demonstrate that CC neurons are necessary for normal callosal axon navigation. They exert an attractive influence on callosal axons, in part via Semaphorin 3C and its receptor Neuropilin-1. By revealing a novel and essential role for these neuronal populations in the pathfinding of a major cerebral commissure, our study brings new perspectives to pathophysiological mechanisms altering CC formation. 相似文献
66.
T. Tyrakowski S. Milutinović I. Schulz C. Hornung K. Heil J. Wiechmann 《The Journal of membrane biology》1978,38(4):333-346
Summary Transport of alanine was studied in isolated plasma membrane vesicles from cat pancreas using a rapid filtration technique. The uptake is osmotically sensitive and the kinetics ofl-alanine transport are biphasic showing a saturable and a nonsaturable component. The saturable component is seen only when a sodium gradient directed from the medium to the vesicular space is present. Under this condition an overshooting uptake ofl-but not ofd-alanine occurs. The Na+ gradient stimulated uptake ofl-alanine is inhibited byl-serine andl-leucine and stimulated when the membrane vesicles had been preloaded withl-alanine,l-serine orl-leucine.The ionophore monensin inhibits stimulation of uptake caused by a sodium gradient. In the presence of valinomycin or carbonyl cyanidep-trifluoromethoxyphenylhydrazone (CFCCP), the sodium-dependent transport is augmented in vesicles preloaded with K2SO4 or H+ ions (intravesicular pH 5.5), respectively. In the presence of different anions, the Na+-dependent transport is stimulated according to increasing anionic penetration through membranes (lipid solubility). We conclude that a sodium dependent electrogenic amino acid transport system is present in pancreatic plasma membranes. 相似文献
67.
68.
The influenza A virus PB1-F2 protein targets the inner mitochondrial membrane via a predicted basic amphipathic helix that disrupts mitochondrial function 总被引:13,自引:0,他引:13
The 11th influenza A virus gene product is an 87-amino-acid protein provisionally named PB1-F2 (because it is encoded by an open reading frame overlapping the PB1 open reading frame). A significant fraction of PB1-F2 localizes to the inner mitochondrial membrane in influenza A virus-infected cells. PB1-F2 appears to enhance virus-induced cell death in a cell type-dependent manner. For the present communication we have identified and characterized a region near the COOH terminus of PB1-F2 that is necessary and sufficient for its inner mitochondrial membrane localization, as determined by transient expression of chimeric proteins consisting of elements of PB1-F2 genetically fused to enhanced green fluorescent protein (EGFP) in HeLa cells. Targeting of EGFP to mitochondria by this sequence resulted in the loss of the inner mitochondrial membrane potential, leading to cell death. The mitochondrial targeting sequence (MTS) is predicted to form a positively charged amphipathic alpha-helix and, as such, is similar to the MTS of the p13(II) protein of human T-cell leukemia virus type 1. We formally demonstrate the functional interchangeability of the two sequences for mitochondrial localization of PB1-F2. Mutation analysis of the putative amphipathic helix in the PB1-F2 reveals that replacement of five basic amino acids with Ala abolishes mitochondrial targeting, whereas mutation of two highly conserved Leu to Ala does not. These findings demonstrate that PB1-F2 possesses an MTS similar to other viral proteins and that this MTS, when fused to EGFP, is capable of independently compromising mitochondrial function and cellular viability. 相似文献
69.
James Martin Jennifer Hudson Tassilo Hornung Wayne D. Frasch 《The Journal of biological chemistry》2015,290(17):10717-10728
Living organisms rely on the FoF1 ATP synthase to maintain the non-equilibrium chemical gradient of ATP to ADP and phosphate that provides the primary energy source for cellular processes. How the Fo motor uses a transmembrane electrochemical ion gradient to create clockwise torque that overcomes F1 ATPase-driven counterclockwise torque at high ATP is a major unresolved question. Using single FoF1 molecules embedded in lipid bilayer nanodiscs, we now report the observation of Fo-dependent rotation of the c10 ring in the ATP synthase (clockwise) direction against the counterclockwise force of ATPase-driven rotation that occurs upon formation of a leash with Fo stator subunit a. Mutational studies indicate that the leash is important for ATP synthase activity and support a mechanism in which residues aGlu-196 and cArg-50 participate in the cytoplasmic proton half-channel to promote leash formation. 相似文献
70.
Tim Iven Ellen Hornung Mareike Heilmann Ivo Feussner 《Plant biotechnology journal》2016,14(1):252-259
Seed oil composed of wax esters with long‐chain monoenoic acyl moieties represents a high‐value commodity for industry. Such plant‐derived sperm oil‐like liquid wax esters are biodegradable and can have excellent properties for lubrication. In addition, wax ester oil may represent a superior substrate for biodiesel production. In this study, we demonstrate that the low‐input oil seed crop Camelina sativa can serve as a biotechnological platform for environmentally benign wax ester production. Two biosynthetic steps catalysed by a fatty alcohol‐forming acyl‐CoA reductase (FAR) and a wax ester synthase (WS) are sufficient to achieve wax ester accumulation from acyl‐CoA substrates. To produce plant‐derived sperm oil‐like liquid wax esters, the WS from Mus musculus (MmWS) or Simmondsia chinensis (ScWS) were expressed in combination with the FAR from Mus musculus (MmFAR1) or Marinobacter aquaeolei (MaFAR) in seeds of Arabidopsis thaliana and Camelina sativa. The three analysed enzyme combinations Oleo3:mCherry:MmFAR1?c/Oleo3:EYFP:MmWS, Oleo3:mCherry:MmFAR1?c/ScWS and MaFAR/ScWS showed differences in the wax ester molecular species profiles and overall biosynthetic performance. By expressing MaFAR/ScWS in Arabidopsis or Camelina up to 59% or 21% of the seed oil TAGs were replaced by wax esters, respectively. This combination also yielded wax ester molecular species with highest content of monounsaturated acyl moieties. Expression of the enzyme combinations in the Arabidopsis fae1 fad2 mutant background high in oleic acid resulted in wax ester accumulation enriched in oleyl oleate (18:1/18:1 > 60%), suggesting that similar values may be obtained with a Camelina high oleic acid line. 相似文献