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排序方式: 共有146条查询结果,搜索用时 15 毫秒
51.
Anindit Mukherjee Gunhild M. Mueller Carol L. Kinlough Nan Sheng Zhijian Wang S. Atif Mustafa Ossama B. Kashlan Thomas R. Kleyman Rebecca P. Hughey 《The Journal of biological chemistry》2014,289(20):14351-14359
The epithelial sodium channel (ENaC) is composed of three homologous subunits (α, β, and γ) with cytoplasmic N and C termini. Our previous work revealed that two cytoplasmic Cys residues in the β subunit, βCys-43 and βCys-557, are Cys-palmitoylated. ENaCs with mutant βC43A/C557A exhibit normal surface expression but enhanced Na+ self-inhibition and reduced channel open probability. Although the α subunit is not palmitoylated, we now show that the two cytoplasmic Cys residues in the γ subunit are palmitoylated. ENaCs with mutant γC33A, γC41A, or γC33A/C41A exhibit reduced activity compared with wild type channels but normal surface expression and normal levels of α and γ subunit-activating cleavage. These mutant channels have significantly enhanced Na+ self-inhibition and reduced open probability compared with wild type ENaCs. Channel activity was enhanced by co-expression with the palmitoyltransferase DHHC2 that also co-immunoprecipitates with ENaCs. Secondary structure prediction of the N terminus of the γ subunit places γCys-33 within an α-helix and γCys-44 on a coil before the first transmembrane domain within a short tract that includes a well conserved His-Gly motif, where mutations have been associated with altered channel gating. Our current and previous results suggest that palmitoylation of the β and γ subunits of ENaCs enhances interactions of their respective cytoplasmic domains with the plasma membrane and stabilizes the open state of the channel. Comparison of activities of channels lacking palmitoylation sites in individual or multiple subunits revealed that γ subunit palmitoylation has a dominant role over β subunit palmitoylation in modulating ENaC gating. 相似文献
52.
53.
Adrienne Jochum Rajko Slapnik Marian Kampschulte Gunhild Martels Markus Heneka Barna Páll-Gergely 《ZooKeys》2014,(410):23-40
A review of the microgastropod genus Systenostoma is provided. Thai and Malaysian species are transferred to a new genus, Angustopila (type species: Systenostoma tamlod Panha & Burch, 1999). A new subterranean Angustopila species is described here. Conchologically, the new species is most similar to the cave-dwelling, Thai A. tamlod (Panha & Burch, 1999). One Thai species (Systenostoma edentata) is transferred to the genus Hypselostoma. Vietnamese members remain in the genus Tonkinospira (nomen novum) for Systenostoma Bavay & Dautzenberg, 1908 (non Systenostoma Marsson, 1887). A comprehensive map of former Systenostoma species is presented. SEM and NanoCT images, including a video of A. huoyani
sp. n. internal shell morphology, provide novel perspectives of the shells of Angustopila and of the scarcely known Vietnamese Tonkinospira species. The biology of these snails is not yet known but collection localities suggest a troglophilic ecology. 相似文献
54.
Harloff HJ Lemcke S Mittasch J Frolov A Wu JG Dreyer F Leckband G Jung C 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2012,124(5):957-969
We developed two mutant populations of oilseed rape (Brassica napus L.) using EMS (ethylmethanesulfonate) as a mutagen. The populations were derived from the spring type line YN01-429 and the
winter type cultivar Express 617 encompassing 5,361 and 3,488 M2 plants, respectively. A high-throughput screening protocol was established based on a two-dimensional 8× pooling strategy.
Genes of the sinapine biosynthesis pathway were chosen for determining the mutation frequencies and for creating novel genetic
variation for rapeseed breeding. The extraction meal of oilseed rape is a rich protein source containing about 40% protein.
Its use as an animal feed or human food, however, is limited by antinutritive compounds like sinapine. The targeting-induced
local lesions in genomes (TILLING) strategy was applied to identify mutations of major genes of the sinapine biosynthesis
pathway. We constructed locus-specific primers for several TILLING amplicons of two sinapine synthesis genes, BnaX.SGT and BnaX.REF1, covering 80–90% of the coding sequences. Screening of both populations revealed 229 and 341 mutations within the BnaX.SGT sequences (135 missense and 13 nonsense mutations) and the BnaX.REF1 sequences (162 missense, 3 nonsense, 8 splice site mutations), respectively. These mutants provide a new resource for breeding
low-sinapine oilseed rape. The frequencies of missense and nonsense mutations corresponded to the frequencies of the target
codons. Mutation frequencies ranged from 1/12 to 1/22 kb for the Express 617 population and from 1/27 to 1/60 kb for the YN01-429
population. Our TILLING resource is publicly available. Due to the high mutation frequencies in combination with an 8× pooling
strategy, mutants can be routinely identified in a cost-efficient manner. However, primers have to be carefully designed to
amplify single sequences from the polyploid rapeseed genome. 相似文献
55.
Jorge Strelin Gino Casassa Gunhild Rosqvist Per Holmlund 《Palaeogeography, Palaeoclimatology, Palaeoecology》2008,260(3-4):299-314
Investigations carried out in the Ema Glacier valley, Tierra del Fuego, on the eastern side of Monte Sarmiento Massif, enable the recognition of five Holocene glacial events. The oldest glacial advance deposited the so-called external moraines of Ema Glacier, with a probable occurrence between 6000 and 5000 14 C y BP without discarding the potential for these deposits to be from Lateglacial time. The remaining four readvances built up a complex inner moraine system named informally internal moraines of Ema Glacier. The oldest recognized till unit that constitutes this proximal moraine system was deposited shortly before 3135 14 C y BP, when glaciolacustrine sedimentation took place during glacier recession. Subsequent glacial advances accumulated till at about 1288 14 C y, shortly after 695 14 C y, and between 379 14 C y and 60 y BP. This chronology of Holocene glacier events coincides with and is well complemented by the one established by other authors for Fiordo Pía at Cordillera Darwin, 75 km to the east. The Ema-Pía chronology is used to calibrate tentatively a series of moraine belts previously identified in the mountain ranges adjacent to Ushuaia, 150 km SE of the surveyed region. A comparative chart shows that the chronological data obtained for the neoglacial readvances in Tierra del Fuego are in accordance with those for the southern Patagonian Andes further north. It follows that the Holocene behavior of the glaciers in the Andean region of Tierra del Fuego and southern Patagonia is essentially a response to the same regional climate change. 相似文献
56.
The 5-year survival rate for oral cavity cancer is poorer than for breast, colon or prostate cancer, and has improved only slightly in the last three decades. Hence, new therapeutic strategies are urgently needed. Here we demonstrate by tissue micro array analysis for the first time that RNA-binding protein La is significantly overexpressed in oral squamous cell carcinoma (SCC). Within this study we therefore addressed the question whether siRNA-mediated depletion of the La protein may interfere with known tumor-promoting characteristics of head and neck SCC cells. Our studies demonstrate that the La protein promotes cell proliferation, migration and invasion of lymph node-metastasized hypopharyngeal SCC cells. We also reveal that La is required for the expression of β-catenin as well as matrix metalloproteinase type 2 (MMP-2) within these cells. Taken together these data suggest a so far unknown function of the RNA-binding protein La in promoting tumor progression of head and neck SCC. 相似文献
57.
Anna Rodnikova Rolf A. Ims Alexander Sokolov Gunhild Skogstad Vasily Sokolov Victor Shtro Eva Fuglei 《Polar Biology》2011,34(10):1609-1614
Here, we report from the first direct observation of a red fox (Vulpes vulpes) intrusion on an arctic fox (Vulpes lagopus) breeding den from the southern Arctic tundra of Yamal Peninsula, Russia in 2007. At the same time, as a current range retraction
of the original inhabitant of the circumpolar tundra zone the arctic fox is going on, the red fox is expanding their range
from the south into arctic habitats. Thus, within large parts of the northern tundra areas the two species are sympatric which
gives opportunities for direct interactions including interference competition. However, direct first-hand observations of
such interactions are rare, especially in the Russian Arctic. In the present study, we observed one red fox taking over an
arctic fox breeding den which resulted in den abandonment by the arctic fox. On July 19, eight arctic fox pups were observed
on the den before the red fox was observed on the same den July 22. The pups were never seen at the den or elsewhere after
the red fox was observed on the den for as long as we stayed in the area (until August 10). Our observation supports the view
that direct interference with red fox on breeding dens may contribute to the range retraction of arctic foxes from the southern
limits of the Arctic tundra in Russia. 相似文献
58.
António M. Baptista Per Harald Jonson Edward Hough Steffen B. Petersen 《Journal of molecular evolution》1998,47(3):353-362
The trypsin family of serine proteases is one of the most studied protein families, with a wealth of amino acid sequence
information available in public databases. Since trypsin-like enzymes are widely distributed in living organisms in nature,
likely evolutionary scenarios have been proposed. A novel methodology for Fourier transformation of biological sequences (FOTOBIS)
is presented. The methodology is well suited for the identification of the size and extent of short repeats in protein sequences.
In the present paper the trypsin family of enzymes is analyzed with FOTOBIS and strong evidence for tandem gene duplication
is found. A likely evolutionary path for the development of present-day trypsins involved an intrinsic extensive tandem gene
duplication of a small DNA fragment of 15–18 nucleotides, corresponding to five or six amino acids. This ancestral trypsin
gene was subsequently duplicated, leading to the earliest version of a full-sized trypsin, from which the contemporary trypsins
have developed.
Received: 22 November 1997 / Accepted: 26 January 1998 相似文献
59.
Summary Some copper-leaching microorganisms were isolated from weathered rock material of old copper deposits. Among these the strain Bacillus sp. L 1 was able to solubilize completely the copper contained in low-grade ore material under optimal conditions. The most suitable leaching solution was sulphite waste liquor from the paper industry. Decreasing effectiveness of metal recovery was observed with increasing particle size and increasing solid-liquid ratio. In silver leaching, a maximum was measured after 3 days followed by a rapid decrease. Possible technical uses of leaching processes are discussed.
Offprint requests to: G. Straube 相似文献
60.
Summary The ability to accumulate copper from aqueous solutions was determined with different yeast species. Yeast cells did not show any significant differences in process kinetics. The uptake was very fast and was influenced by environmental factors. The metal-accumulating capacity differed among the tested strains. The yeastsCandida tropicalis andPichia guilliermondii were chosen for extensive research. Cells of the stationary growth phase were able to adsorb a high amount of copper. The uptake capacity decreased with increasing biomass concentration. Copper adsorption obeyed the Freundlich isotherm. Optimal pH range was between 5 and 7. The biomass could be used repeatedly for biosorption after desorption by mineral acids. 相似文献