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71.
Melanie Ann Sacco Kamila Koropacka Eric Grenier Marianne J. Jaubert Alexandra Blanchard Aska Goverse Geert Smant Peter Moffett 《PLoS pathogens》2009,5(8)
Plant NB-LRR proteins confer robust protection against microbes and metazoan
parasites by recognizing pathogen-derived avirulence (Avr) proteins that are
delivered to the host cytoplasm. Microbial Avr proteins usually function as
virulence factors in compatible interactions; however, little is known about the
types of metazoan proteins recognized by NB-LRR proteins and their relationship
with virulence. In this report, we demonstrate that the secreted protein RBP-1
from the potato cyst nematode Globodera pallida elicits defense
responses, including cell death typical of a hypersensitive response (HR),
through the NB-LRR protein Gpa2. Gp-Rbp-1 variants from
G. pallida populations both virulent and avirulent to
Gpa2 demonstrated a high degree of polymorphism, with
positive selection detected at numerous sites. All Gp-RBP-1
protein variants from an avirulent population were recognized by Gpa2, whereas
virulent populations possessed Gp-RBP-1 protein variants both
recognized and non-recognized by Gpa2. Recognition of Gp-RBP-1
by Gpa2 correlated to a single amino acid polymorphism at position 187 in the
Gp-RBP-1 SPRY domain. Gp-RBP-1 expressed
from Potato virus X elicited Gpa2-mediated defenses that required Ran
GTPase-activating protein 2 (RanGAP2), a protein known to interact with the Gpa2
N terminus. Tethering RanGAP2 and Gp-RBP-1 variants via fusion
proteins resulted in an enhancement of Gpa2-mediated responses. However,
activation of Gpa2 was still dependent on the recognition specificity conferred
by amino acid 187 and the Gpa2 LRR domain. These results suggest a two-tiered
process wherein RanGAP2 mediates an initial interaction with pathogen-delivered
Gp-RBP-1 proteins but where the Gpa2 LRR determines which
of these interactions will be productive. 相似文献
72.
The aim of this study was to develop a simple method to quantify peptide uptake by the periodontopathogenic bacterium Porphyromonas gingivalis. After incubation of bacterial cells with self-quenched fluorescent bovine serum albumin (DQ Green BSA), the fluorescence measured in the supernatant of the assay mixture indicated the degree of protein degradation, whereas the fluorescence associated with the lysate of washed cells indicated the amount of BSA-derived fragments incorporated by the bacteria. The optimal conditions for uptake of fluorophore-labeled albumin fragments were found to be mid-log grown cells, 150 m M NaCl in phosphate buffer, pH 7, 37 degrees C, and anaerobiosis. Among the protease inhibitors tested, 4-(2-aminoethyl)-benzene sulfonyl-fluoride hydrochloride (AEBSF) and cathepsin B inhibitor II caused a significant inhibition of the uptake of BSA-derived peptides. This assay was applicable for other commercially available fluorescent substrates. This simple method may be useful to investigate protein processing in proteolytic bacteria and for studying the effects of environmental parameters or cell treatments on the peptide uptake. 相似文献
73.
Production and properties of bacteriocin-like inhibitory substances from the swine pathogen Streptococcus suis serotype 2 总被引:1,自引:0,他引:1
Streptococcus suis serotype 2 is a major pathogen found in the upper respiratory tract of swine. In this study, isolates of this bacterial species were tested for the production of bacteriocin-like inhibitory substances (BLIS). Of the 38 strains tested, four inhibited the growth of other S. suis isolates according to a deferred-antagonism plate assay. Interestingly, three of the strains were originally isolated from healthy carrier pigs and were considered nonvirulent. Three isolates (94-623, 90-1330, and AAH4) that produced BLIS in liquid broth were selected for further characterization. None of the inhibitory activities was related to the production of either organic acids or hydrogen peroxide. The BLIS produced by these strains were heat stable and proteinase K, pronase, and elastase sensitive but were trypsin and chymotrypsin resistant. They were stable at pH 2 and 12 and had molecular masses in the range of 14 to 30 kDa. Maximum production was observed during the mid-log phase. Following a curing procedure with novobiocin, only 90-1330 lost the ability to produce BLIS, suggesting that the BLIS might be plasmid encoded. Analysis of the inhibitory spectra revealed that the BLIS-producing strains also inhibited the growth of Actinobacillus minor, Actinobacillus porcinus, Enterococcus durans, Micrococcus luteus, Streptococcus agalactiae, Streptococcus dysgalactiae subsp. dysgalactiae, Streptococcus equi subsp. zooepidemicus, and S. dysgalactiae subsp. equisimilis. This study reports for the first time the ability of the swine pathogen S. suis serotype 2 to produce BLIS with the characteristics of classic bacteriocins. Further studies are required to investigate the possibility of using bacteriocin-producing strains to prevent swine infections caused by virulent strains of S. suis serotype 2. 相似文献
74.
Naureckiene S Ma L Sreekumar K Purandare U Lo CF Huang Y Chiang LW Grenier JM Ozenberger BA Jacobsen JS Kennedy JD DiStefano PS Wood A Bingham B 《Archives of biochemistry and biophysics》2003,420(1):55-67
The NARC 1 gene encodes a novel proteinase K family proteinase. The domain structure of rat Narc 1 resembles that of the subtilisin-like proprotein convertases (SPCs), except that rNarc 1 lacks the canonical P-domain of SPCs, retaining only the RGD motif as part of what might be a cryptically functioning P-domain. Narc 1 undergoes autocatalytic intramolecular processing at the site LVFAQ/, resulting in the cleavage of its prosegment and the generation of an active proteinase with a broad alkaline pH optimum and no apparent calcium requirement for activity. Both primary and secondary structural determinants influence Narc 1 substrate recognition. Our functional characterization of Narc 1 reinforces the inference drawn from the analysis of its predicted structure that this enzyme is most closely related to representatives of the proteinase K family, but that it is also sufficiently different to warrant its possible classification in a separate sub-family. 相似文献
75.
Isolation and culture of the three vascular cell types from a small vein biopsy sample 总被引:4,自引:0,他引:4
Grenier G Remy-Zolghadri M Guignard R Bergeron F Labbe R Auger FA Germain L 《In vitro cellular & developmental biology. Animal》2003,39(3-4):131-139
Summary The availability of small-diameter blood vessels remains a significant problem in vascular reconstruction. In small-diameter
blood vessels, synthetic grafts resulted in low patency; the addition of endothelial cells (EC) has clearly improved this
parameter, thereby proving the important contribution of the cellular component to the functionality of any construct. Because
the optimal source of cells should be autologous, the adaptation of existing methods for the isolation of all the vascular
cell types present in a single and small biopsy sample, thus reducing patient’s morbidity, is a first step toward future clinical
applications of any newly developed tissue-engineered blood vessel. This study describes such a cell-harvesting procedure
from vein biopsy samples of canine and human origin. For this purpose, we combined preexisting mechanical methods for the
isolation of the three vascular cell types: EC by scraping of the endothelium using a scalpel blade, vascular smooth muscle
cells (VSMC), and perivascular fibroblasts according to the explant method. Once in culture, cells rapidly grew with the high
level of enrichment. The morphological, phenotypical, and functional expected criteria were maintained: EC formed cobblestone
colonies, expressed the von Willebrand factor, and incorporated acetylated low-density lipoprotein (LDL); VSMC were elongated
and contracted when challenged by vasoactive agents; perivascular fibroblasts formed a mechanically resistant structure. Thus,
we demonstrated that an appropriate combination of preexisting harvesting methods is suitable to isolate simultaneously the
vascular cell types present in a single biopsy sample. Their functional characteristics indicated that they were suitable
for the cellularization of synthetic prosthesis or the reconstruction of functional multicellular autologous organs by tissue
engineering. 相似文献
76.
77.
Grenier JM Wang L Manji GA Huang WJ Al-Garawi A Kelly R Carlson A Merriam S Lora JM Briskin M DiStefano PS Bertin J 《FEBS letters》2002,530(1-3):73-78
PYRIN-containing Apaf-1-like proteins (PYPAFs) are a recently identified family of proteins thought to function in apoptotic and inflammatory signaling pathways. PYPAF1 and PYPAF7 proteins have been found to assemble with the PYRIN–CARD protein ASC and coordinate the activation of NF-κB and pro-caspase-1. To determine if other PYPAF family members function in pro-inflammatory signaling pathways, we screened five other PYPAF proteins (PYPAF2, PYPAF3, PYPAF4, PYPAF5 and PYPAF6) for their ability to activate NF-κB and pro-caspase-1. Co-expression of PYPAF5 with ASC results in a synergistic activation of NF-κB and the recruitment of PYPAF5 to punctate structures in the cytoplasm. The expression of PYPAF5 is highly restricted to granulocytes and T-cells, indicating a role for this protein in inflammatory signaling. In contrast, PYPAF2, PYPAF3, PYPAF4 and PYPAF6 failed to colocalize with ASC and activate NF-κB. PYPAF5 also synergistically activated caspase-1-dependent cytokine processing when co-expressed with ASC. These findings suggest that PYPAF5 functions in immune cells to coordinate the transduction of pro-inflammatory signals to the activation of NF-κB and pro-caspase-1. 相似文献
78.
Drouet M Mourcin F Grenier N Mayol JF Leroux V Hérodin F Sotto JJ 《Canadian journal of physiology and pharmacology》2002,80(7):700-709
Abstract: Bone marrow aplasia observed following ionizing radiation exposure (Total Body Irradiation; gamma dose range: 2-10 Gy) is a result, in particular, of the radiation-induced (RI) apoptosis in hematopoietic stem and progenitor cells (HSPC). We have previously shown in a baboon model of mobilized peripheral blood CD34+ cell irradiation in vitro that RI apoptosis in HSPC was an early event, mostly occurring within the first 24 hours, which involves the CD95 Fas pathway. Apoptosis may be significantly reduced with a combination of 4 cytokines (4F): Stem Cell Factor (SCF), FLT-3 Ligand (FL), thrombopoietin (TPO), and interleukin-3 (IL-3), each at 50 ng x mL(-1) (15% survival versus <3% untreated cells, 24 h post-irradiation at 2.5 Gy). In this study we show that addition of TNF-alpha(800 IU/ml) induces an increase in 4F efficacy in terms of cell survival 24 h after incubation (26% survival after 24 h irradiation exposure at 2.5 Gy) and amplification (k) of CD34+ cells after 6 days in a serum free culture medium (SFM) (kCD34+ = 4.3 and 6.3 respectively for 4F and successive 4F + TNF-a/ 4F treatments). In addition, the 4F combination allows culture on pre-established allogenic irradiated stromal cells in vitro at 4 Gy (kCD34+ = 4.5). Overall this study suggests (i) the potential therapeutic interest for an early administration of anti-apoptotic cytokines with or without hematopoiesis inhibitors (emergency cytokine therapy) and (ii) the feasibility in the accidentally irradiated individual, of autologous cell therapy based on ex vivo expansion in order to perform autograft of residual HSPC collected after the accident. 相似文献
79.
Magali Esquibet Eric Grenier Olivier Plantard Fouad Abbad Andaloussi Georges Caubel 《Génome》2003,46(6):1077-1083
DNA polymorphism in the Ditylenchus dipsaci complex was investigated using amplified fragment length polymorphism (AFLP) to determine the relationships among populations growing mainly on Vicia faba and to develop diagnostic markers. Twenty-two populations of D. dipsaci originating from different geographical areas and one population of Ditylenchus myceliophagus were used. AFLP proved to be a powerful method to reveal intraspecific polymorphism even within the giant type. The analysis showed a clear distinction between the giant and normal populations, with genetic distances similar to those observed between normal populations and D. myceliophagus or giant populations and D. myceliophagus, strengthening the hypothesis that these two nematode types could be considered distinct species. Two specific AFLP markers differentiating the two types were converted into sequenced characterized amplified region (SCAR) markers. Used in a multiplex PCR, the SCAR primers proved to be a rapid and efficient tool to identify the giant and the normal types of D. dipsaci. 相似文献
80.
Maria Luisa Dindo Simon Grenier Luca Sighinolfi & Piero Baronio 《Entomologia Experimentalis et Applicata》2006,120(3):167-174
Quantitative and qualitative parameters of Exorista larvarum (L.) (Diptera: Tachinidae) reared on two insect-material-free artificial media and in the factitious host Galleria mellonella L. (Lepidoptera: Pyralidae) were compared. Significantly higher puparial yields and weights were obtained in both a milk-based and a veal homogenate-based medium than in the factitious host. Longevity and parasitization rates were not different between the in vitro- and in vivo-reared flies. Despite the greater puparial weight of the veal medium-reared E. larvarum females, the number of eggs laid by these females on host larvae was not higher than that of females reared under the other two rearing conditions. Moreover, in a complementary experiment, with homogeneous puparial weights of milk medium- and host-reared females, the former oviposited fewer eggs. Hence, puparial weight alone is not a reliable quality parameter for E. larvarum reared on artificial media. Lower amino acid content, with a deficiency in aromatic amino acids and an excess in proline, was found for in vitro third instar parasitoid larvae reared on both media compared to the in vivo-reared ones. These results suggest a correlation between the amino acid deficiency and imbalance of medium-reared larvae and the lower number of eggs laid by the females obtained. 相似文献