全文获取类型
收费全文 | 125篇 |
免费 | 5篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 2篇 |
2017年 | 1篇 |
2015年 | 8篇 |
2014年 | 5篇 |
2013年 | 11篇 |
2012年 | 11篇 |
2011年 | 2篇 |
2010年 | 6篇 |
2009年 | 6篇 |
2008年 | 5篇 |
2007年 | 2篇 |
2006年 | 4篇 |
2005年 | 4篇 |
2004年 | 3篇 |
2003年 | 1篇 |
2002年 | 4篇 |
2001年 | 9篇 |
2000年 | 2篇 |
1999年 | 8篇 |
1998年 | 3篇 |
1997年 | 3篇 |
1995年 | 2篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有130条查询结果,搜索用时 31 毫秒
71.
AIMS: Enumeration of total, active or viable probiotic micro-organisms from liquid or solid commercial feedstuffs was studied during processing and storage. METHODS AND RESULTS: After sample preparation, an epifluorescence microscopy technique and a plating method were investigated comparatively. It was shown that (i) on the day of manufacture, active or viable bacteria were in equivalent amounts and that viable numbers then decreased, depending on the different processing and storage factors enhancing ABNC production, (ii) the amount of total and active lactobacilli remained close and quite stable for months at a high level (>10(8) active fluorescent units). CONCLUSIONS: Processing and storage promoted ABNC cells in the products tested. Consequently, both techniques should be used to evaluate the viable-dead-active status of bacteria for which functional properties are claimed. SIGNIFICANCE AND IMPACT OF THE STUDY: Enumeration of the whole probiotic bacterial population should be take into account for guidelines and labelling since non-viable bacteria could have a probiotic effect. 相似文献
72.
U373-MG response to interleukin-1β-induced oxidative stress 总被引:2,自引:0,他引:2
Malaplate-Armand C Gueguen Y Bertrand P Ferrari L Batt AM 《Cell biology and toxicology》2000,16(3):155-163
Oxidative stress has been involved in various neurological disorders and, in the central nervous system, astrocytes represent
the cell type that contributes to neuroprotection via glutathione (GSH) metabolism, GSH-metabolizing enzymes like γ-glutamyltransferase
(GGT), and apoE secretion. In this study, using IL-1β, a proinflammatory and prooxidant cytokine that is increased in numerous
pathological situations, cells of astrocytoma cell line U373-MG were exposed to an oxidative stress, leading to c-Jun and
c-Fos activation. IL-1β decreased both GGT activity and intracellular GSH content and increased apoE secretion, initiating
astroglial response to injury. We observed that antioxidants inhibit IL-1β effects on c-Jun and c-Fos proteins, GGT activity
and the GSH pool but not on apoE secretion. Our results allow us to conclude that neurological disorders associated with an
IL-1β-induced oxidative stress could be, at least experimentally, reversible in the presence of one antioxidant, N-acetylcysteine.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
73.
Valerie Desquiret-Dumas Geraldine Leman Celine Wetterwald Stephanie Chupin Anaïs Lebert Salim Khiati Morgane Le Mao Guillaume Geffroy Mariame Selma Kane Arnaud Chevrollier David Goudenege Cedric Gadras Lydie Tessier Magalie Barth Stephanie Leruez Patrizia Amati-Bonneau Daniel Henrion Dominique Bonneau Naig Gueguen 《生物化学与生物物理学报:疾病的分子基础》2019,1865(9):2475-2489
Due to its pivotal role in NADH oxidation and ATP synthesis, mitochondrial complex I (CI) emerged as a crucial regulator of cellular metabolism. A functional CI relies on the sequential assembly of nuclear- and mtDNA-encoded subunits; however, whether CI assembly status is involved in the metabolic adaptations in CI deficiency still remains largely unknown. Here, we investigated the relationship between CI functions, its structure and the cellular metabolism in 29 patient fibroblasts representative of most CI mitochondrial diseases. Our results show that, contrary to the generally accepted view, a complex I deficiency does not necessarily lead to a glycolytic switch, i.e. the so-called Warburg effect, but that this particular metabolic adaptation is a feature of CI assembly defect. By contrast, a CI functional defect without disassembly induces a higher catabolism to sustain the oxidative metabolism. Mechanistically, we demonstrate that reactive oxygen species overproduction by CI assembly intermediates and subsequent AMPK-dependent Pyruvate Dehydrogenase inactivation are key players of this metabolic reprogramming. Thus, this study provides a two-way-model of metabolic responses to CI deficiencies that are central not only in defining therapeutic strategies for mitochondrial diseases, but also in all pathophysiological conditions involving a CI deficiency. 相似文献
74.
75.
IS911 naturally produces transposase (OrfAB) derivatives truncated at the C-terminal end (OrfAB-CTF) and devoid of the catalytic domain. A majority species, OrfAB*, was produced at higher levels at 42 degrees C than at 30 degrees C suggesting that it is at least partly responsible for the innate reduction in IS911 transposition activity at higher temperatures. An engineered equivalent of similar length, OrfAB[1-149], inhibited transposition activity in vivo or in vitro when produced along with full-length transposase. We isolated several point mutants showing higher activity than the wild-type IS911 at 42 degrees C. These fall into two regions of the transposase. One, located in the N-terminal segment of OrfAB, lies between or within two regions involved in protein multimerization. The other is located within the C-terminal catalytic domain. The N-terminal mutations resulted in reduced levels of OrfAB* while the C-terminal mutation alone appeared not to affect OrfAB* levels. Combination of N- and C-terminal mutations greatly reduced OrfAB* levels and transposition was concomitantly high even at 42 degrees C. The mechanism by which truncated transposase species are generated and how they intervene to reduce transposition activity is discussed. While transposition activity of these multiply mutated derivatives in vivo was resistant to temperature, the purified OrfAB derivatives retained an inherent temperature-sensitive phenotype in vitro. This clearly demonstrates that temperature sensitivity of IS911 transposition is a complex phenomenon with several mechanistic components. These results have important implications for the several other transposons and insertion sequences whose transposition has also been shown to be temperature-sensitive. 相似文献
76.
Fall S Mercier A Bertolla F Calteau A Gueguen L Perrière G Vogel TM Simonet P 《PloS one》2007,2(10):e1055
Horizontal gene transfer (HGT) is recognized as the major force for bacterial genome evolution. Yet, numerous questions remain about the transferred genes, their function, quantity and frequency. The extent to which genetic transformation by exogenous DNA has occurred over evolutionary time was initially addressed by an in silico approach using the complete genome sequence of the Ralstonia solanacearum GMI1000 strain. Methods based on phylogenetic reconstruction of prokaryote homologous genes families detected 151 genes (13.3%) of foreign origin in the R. solanacearum genome and tentatively identified their bacterial origin. These putative transfers were analyzed in comparison to experimental transformation tests involving 18 different genomic DNA positions in the genome as sites for homologous or homeologous recombination. Significant transformation frequency differences were observed among these positions tested regardless of the overall genomic divergence of the R. solanacearum strains tested as recipients. The genomic positions containing the putative exogenous DNA were not systematically transformed at the highest frequencies. The two genomic "hot spots", which contain recA and mutS genes, exhibited transformation frequencies from 2 to more than 4 orders of magnitude higher than positions associated with other genes depending on the recipient strain. These results support the notion that the bacterial cell is equipped with active mechanisms to modulate acquisition of new DNA in different genomic positions. Bio-informatics study correlated recombination "hot-spots" to the presence of Chi-like signature sequences with which recombination might be preferentially initiated. The fundamental role of HGT is certainly not limited to the critical impact that the very rare foreign genes acquired mainly by chance can have on the bacterial adaptation potential. The frequency to which HGT with homologous and homeologous DNA happens in the environment might have led the bacteria to hijack DNA repair mechanisms in order to generate genetic diversity without losing too much genomic stability. 相似文献
77.
78.
Wilfried Thuiller Laura J. Pollock Maya Gueguen Tamara Münkemüller 《Ecology letters》2015,18(12):1321-1328
The extent that biotic interactions and dispersal influence species ranges and diversity patterns across scales remains an open question. Answering this question requires framing an analysis on the frontier between species distribution modelling (SDM), which ignores biotic interactions and dispersal limitation, and community ecology, which provides specific predictions on community and meta‐community structure and resulting diversity patterns such as species richness and functional diversity. Using both empirical and simulated datasets, we tested whether predicted occurrences from fine‐resolution SDMs provide good estimates of community structure and diversity patterns at resolutions ranging from a resolution typical of studies within reserves (250 m) to that typical of a regional biodiversity study (5 km). For both datasets, we show that the imprint of biotic interactions and dispersal limitation quickly vanishes when spatial resolution is reduced, which demonstrates the value of SDMs for tracking the imprint of community assembly processes across scales. 相似文献
79.