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51.
George Boyan Leslie Williams Andrea Legl Zsofia Herbert 《Cell and tissue research》2010,341(2):259-277
The central complex of the grasshopper Schistocerca gregaria develops to completion during embryogenesis. A major cellular contribution to the central complex is from the w, x, y, z
lineages of the pars intercerebralis, each of which comprises over 100 cells, making them by far the largest in the embryonic
protocerebrum. Our focus has been to find a cellular mechanism that allows such a large number of cell progeny to be generated
within a restricted period of time. Immunohistochemical visualization of the chromosomes of mitotically active cells has revealed
an almost identical linear array of proliferative cells present simultaneously in each w, x, y, z lineage at 50% of embryogenesis.
This array is maintained relatively unchanged until almost 70% of embryogenesis, after which mitotic activity declines and
then ceases. The array is absent from smaller lineages of the protocerebrum not associated with the central complex. The proliferative
cells are located apically to the zone of ganglion mother cells and amongst the progeny of the neuroblast. Comparisons of
cell morphology, immunoreactivity (horseradish peroxidase, repo, Prospero), location in lineages and spindle orientation have
allowed us to distinguish the proliferative cells in an array from neuroblasts, ganglion mother cells, neuronal progeny and
glia. Our data are consistent with the proliferative cells being secondary (amplifying) progenitors and originating from a
specific subtype of ganglion mother cell. We propose a model of the way that neuroblasts, ganglion mother cells and secondary
progenitors together produce the large cell numbers found in central complex lineages. 相似文献
52.
Jović M Kean MJ Szentpetery Z Polevoy G Gingras AC Brill JA Balla T 《Molecular biology of the cell》2012,23(8):1533-1545
Gaucher disease is a lysosomal storage disorder caused by a defect in the degradation of glucosylceramide catalyzed by the lysosomal enzyme β-glucocerebrosidase (GBA). GBA reaches lysosomes via association with its receptor, lysosomal integral membrane protein type 2 (LIMP-2). We found that distinct phosphatidylinositol 4-kinases (PI4Ks) play important roles at multiple steps in the trafficking pathway of the LIMP-2/GBA complex. Acute depletion of phosphatidylinositol 4-phosphate in the Golgi caused accumulation of LIMP-2 in this compartment, and PI4KIIIβ was found to be responsible for controlling the exit of LIMP-2 from the Golgi. In contrast, depletion of PI4KIIα blocked trafficking at a post-Golgi compartment, leading to accumulation of LIMP-2 in enlarged endosomal vesicles. PI4KIIα depletion also caused secretion of missorted GBA into the medium, which was attenuated by limiting LIMP-2/GBA exit from the Golgi by PI4KIIIβ inhibitors. These studies identified PI4KIIIβ and PI4KIIα as important regulators of lysosomal delivery of GBA, revealing a new element of control to sphingolipid homeostasis by phosphoinositides. 相似文献
53.
Linda C. Weiss Ralph Tollrian Zsofia Herbert Christian Laforsch 《Journal of morphology》2012,273(12):1392-1405
The freshwater crustacean Daphnia is well known for its phenotypic plasticity, in which environmental cues are perceived by the nervous system and transformed into phenotypic adaptations beneficial under current conditions. Critical knowledge regarding the distribution and localization of neuronal antigens or neurotransmitters and differentially expressed proteins is sparse. Here, we applied immunohistochemical and histological‐staining methods in combination with confocal laser scanning microscopy on whole mount preparations in Daphnia pulex, Daphnia longicephala, and Daphnialumholtzi. We document the nervous system, elements of the sensory system, and cell clusters with secretory characteristics in the Daphnia head. This is the first report on the nervous system of the species D.longicephala and D.lumholtzi. The methods established in this investigation will help to foster research on specific neuronal mechanisms in this rapidly advancing model system of life science research. J. Morphol., 2012. © 2012 Wiley Periodicals, Inc. 相似文献
54.
Balla A Tuymetova G Toth B Szentpetery Z Zhao X Knight ZA Shokat K Steinbach PJ Balla T 《Biochemistry》2008,47(6):1599-1607
Molecular modeling and site directed mutagenesis were used to analyze the structural features determining the unique inhibitor sensitivities of type-III phosphatidylinositol 4-kinase enzymes (PI4Ks). Mutation of a highly conserved Tyr residue that provides the bottom of the hydrophobic pocket for ATP yielded a PI4KIIIbeta enzyme that showed greatly reduced wortmannin sensitivity and was catalytically still active. Similar substitutions were not tolerated in the type-IIIalpha enzyme rendering it catalytically inactive. Two conserved Cys residues located in the active site of PI4KIIIalpha were found responsible for the high sensitivity of this enzyme to the oxidizing agent, phenylarsine oxide. Mutation of one of these Cys residues reduced the phenylarsine oxide sensitivity of the enzyme to the same level observed with the PI4KIIIbeta protein. In search of inhibitors that would discriminate between the closely related PI4KIIIalpha and -IIIbeta enzymes, the PI3Kgamma inhibitor, PIK93, was found to inhibit PI4KIIIbeta with significantly greater potency than PI4KIIIalpha. These studies should aid development of subtype-specific inhibitors of type-III PI4Ks and help to better understand the significance of localized PtdIns4P production by the various PI4Ks isoforms in specific cellular compartments. 相似文献
55.
Myrmecochory (the dispersal of seeds by ants) is a significant ecological process in sclerophyll woodlands, but habitat disturbance is known to alter the extent and success of this mutualism. We investigated the influence of soil disturbance on the composition of the seed-dispersing ant community. Surveys were conducted in roadside verges where soils are regularly disturbed by road maintenance activities. Using a ‘cafeteria’ bait station approach, we selected 24 roads of different widths to investigate ant composition and abundance in relation to soil disturbance. We found ant species richness was greater in non-disturbed than disturbed zones, where road verge width significantly influenced results. The composition and abundance of individual seed-dispersing ant species varied between disturbed and non-disturbed zones. Rhytidoponera metallica were more abundant in non-disturbed sites, whereas Melophorus bruneus and Monomorium rothseini were more frequently recorded in disturbed areas. Commonly found Iridomyrmex purpureus was significantly more abundant in disturbed zones in narrow roadsides and vice versa in wide roadsides, and strongly influenced total community composition. Variation in the abundance of commonly recorded Iridomyrmex and Monomorium genera were related more to site conditions (roadside width and habitat) than soil disturbance. The rich composition of seed dispersing ants in roadside environments, and the effects of soil disturbances on these ant communities that we describe, provide a key insight to important seed dispersal vectors occurring in fragmented rural landscapes. 相似文献
56.
Two percent of men with early-onset prostate cancer harbor germline mutations in the BRCA2 gene 总被引:5,自引:0,他引:5
Edwards SM Kote-Jarai Z Meitz J Hamoudi R Hope Q Osin P Jackson R Southgate C Singh R Falconer A Dearnaley DP Ardern-Jones A Murkin A Dowe A Kelly J Williams S Oram R Stevens M Teare DM Ponder BA Gayther SA Easton DF Eeles RA;Cancer Research UK/Bristish Prostate Group UK Familial Prostate Cancer Study Collaborators;British Association of Urological Surgeons Section of Oncology 《American journal of human genetics》2003,72(1):1-12
Studies of families with breast cancer have indicated that male carriers of BRCA2 mutations are at increased risk of prostate cancer, particularly at an early age. To evaluate the contribution of BRCA2 mutations to early-onset prostate cancer, we screened the complete coding sequence of BRCA2 for germline mutations, in 263 men with diagnoses of prostate cancer who were =55 years of age. Protein-truncating mutations were found in six men (2.3%; 95% confidence interval 0.8%-5.0%), and all of these mutations were clustered outside the ovarian-cancer cluster region. The relative risk of developing prostate cancer by age 56 years from a deleterious germline BRCA2 mutation was 23-fold. Four of the patients with mutations did not have a family history of breast or ovarian cancer. Twenty-two variants of uncertain significance were also identified. These results confirm that BRCA2 is a high-risk prostate-cancer-susceptibility gene and have potential implications for the management of early-onset prostate cancer, in both patients and their relatives. 相似文献
57.
The effects of the alkali metal ions (Li+, Na+ and K+) on the growth and on certain virulence factors (adhesion, cell-surface hydrophobicity and germinating ability) of Candida albicans were determined. High concentrations of these ions displayed an inhibitory effect on the growth of the Candida cells; preincubation in their presence showed a negative effect on all virulence factors studied. The changes induced during the preincubation remained there even when high concentration of the ions was removed from the cell suspension. In contrast, a considerable growth was found at high Na+ and K+ concentrations. Although alkali metal ions significantly decreased certain virulence traits of the fungus they did not totally inhibit adhesion and germ-tube formation. This suggests that C. albicans may represent a health hazard even at a high salt concentration. 相似文献
58.
Genetic polymorphism of interleukin-8 (IL-8) is associated with Helicobacter pylori-induced duodenal ulcer 总被引:2,自引:0,他引:2
Gyulai Z Klausz G Tiszai A Lénárt Z Kása IT Lonovics J Mándi Y 《European cytokine network》2004,15(4):353-358
BACKGROUND AND AIMS: Helicobacter pylori infection almost invariably causes chronic gastritis, but only a proportion of the infected subjects develop peptic ulcers. The local inflammation associated with H. pylori infection is characterized by an increased production of the proinflammatory cytokines IL-1-B, IL-6, IL-8 and TNF-alpha. Since such cytokine production is often determined by the genetic polymorphism of regions regulating cytokine gene expression, we investigated the relationship between TNF-alpha and IL-8 polymorphisms and the development of duodenal ulcer disease. We also sought a correlation between the promoter polymorphism of the lipopolysaccharide (LPS) receptor CD14 and the formation of peptic ulcer, because CD14 plays a crucial role in the initiation of the cytokine cascade. METHODS: Genomic DNA extracted from the peripheral blood of 69 patients with H. pylori-positive duodenal ulcer disease and 47 H. pylori-positive healthy controls was analyzed for TNF-alpha -308 promoter polymorphism by RFLP, and for IL-8 -251 polymorphism by ARMS. Genetic polymorphism within the promoter of the CD14 gene was identified using the LightCycler instrument via melting point analysis. RESULTS: No significant correlation could be revealed between the TNF-alpha and CD14 promoter polymorphisms and the clinical outcome of H. pylori infection. The IL-8 A/T heterozygote mutant variant was detected with a significantly higher frequency (65.22%) among the ulcer patients than among the healthy, H. pylori-positive blood donors (36.17%), while the frequency of the normal allelic genotype (TT) was significantly higher in the control group (44.6% vs 15.9%). CONCLUSION: Analysis of the genetic predisposition to enhanced cytokine production revealed a significant association only for the IL-8 polymorphism. This observation draws attention to the possible importance of IL-8 polymorphism as a genetic predisposing factor in the pathomechanism of H. pylori-induced duodenal ulcer disease, and to the relative protection from duodenal ulcer disease that is associated with the TT genotype. 相似文献
59.
Anders S. Huseth Jessica D. Petersen Katja Poveda Zsofia Szendrei Brian A. Nault George G. Kennedy Russell L. Groves 《PloS one》2015,10(6)
Landscape-scale intensification of individual crops and pesticide use that is associated with this intensification is an emerging, environmental problem that is expected to have unequal effects on pests with different lifecycles, host ranges, and dispersal abilities. We investigate if intensification of a single crop in an agroecosystem has a direct effect on insecticide resistance in a specialist insect herbivore. Using a major potato pest, Leptinotarsa decemlineata, we measured imidacloprid (neonicotinoid) resistance in populations across a spatiotemporal crop production gradient where potato production has increased in Michigan and Wisconsin, USA. We found that concurrent estimates of area and temporal frequency of potato production better described patterns of imidacloprid resistance among L. decemlineata populations than general measures of agricultural production (% cropland, landscape diversity). This study defines the effects individual crop rotation patterns can have on specialist herbivore insecticide resistance in an agroecosystem context, and how impacts of intensive production can be estimated with general estimates of insecticide use. Our results provide empirical evidence that variation in the intensity of neonicotinoid-treated potato in an agricultural landscape can have unequal impacts on L. decemlineata insecticide insensitivity, a process that can lead to resistance and locally intensive insecticide use. Our study provides a novel approach applicable in other agricultural systems to estimate impacts of crop rotation, increased pesticide dependence, insecticide resistance, and external costs of pest management practices on ecosystem health. 相似文献
60.
Ribosomal proteins assist the assembly and increase the stability of ribosomal RNA, without requiring ATP for their action. Some ribosomal proteins are also known to have essential functions outside the ribosome, i.e. promiscuity of functions that appears to correlate with their structural disorder. Here we addressed if certain ribosomal proteins with RNA chaperone activity and with a significant level of disorder also have protein-chaperone activity in vitro. Four proteins of the large subunit of Escherichia coli ribosome, L15, L16, L18 and L19 have been tested in three chaperone assays, in which all of them exhibited potent chaperone activity, commensurable with that of heat shock protein 90 kDa. These observations highlight possible novel aspects of the promiscuous functions of ribosomal proteins outside of the ribosome. 相似文献