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排序方式: 共有243条查询结果,搜索用时 15 毫秒
1.
《Bioorganic & medicinal chemistry》2014,22(17):4566-4571
The National Cancer Institute (NCI) Diversity Set was screened for potential inhibitors of phospho-MurNAc-pentapeptide translocase MraY from Escherichia coli using a primary fluorescence enhancement assay, followed by a secondary radiochemical assay. One new MraY inhibitor was identified from this screen, a naphthylisoquinoline alkaloid michellamine B, which inhibited E. coli MraY (IC50 456 μM) and Bacillus subtilis MraY (IC50 386 μM), and which showed antimicrobial activity against B. subtilis (MIC 16 μg/mL). Following an earlier report of halogenated fluoresceins identified from a combined MraY/MurG screen, three halogenated fluoresceins were tested as inhibitors of E. coli MraY and E. coli MurG, and phloxine B was identified as an inhibitor of E. coli MraY (IC50 32 μM). Molecular docking of inhibitor structures against the structure of Aquifex aeolicus MraY indicates that phloxine B appears to bind to the Mg2+ cofactor in the enzyme active site, while michellamine B binds to a hydrophobic groove formed between transmembrane helices 5 and 9. 相似文献
2.
Peter H. Seidl Jochen R. Golecki Norbert Franken Karl Heinz Schleifer 《Archives of microbiology》1985,142(2):121-127
The peptide subunit pentapeptide H-L-Ala-D-Glu(L-Lys-D-Ala-D-Ala-OH)-NH2 of peptidoglycan was localized in the cell walls of several Gram-positive bacteria employing the indirect immunoferritin technique. Specific antibodies to the D-alanyl-D-alanine moiety of non-crosslinked peptide subunit pentapeptide were raised in rabbits by immunization with synthetic immunogen albumin-(CH2CO-Gly-L-Ala-L-Ala-D-Ala-D-Ala-OH)39. Specificity of these antibodies for the peptide subunit pentapeptide and not for the peptide subunit tetrapeptide was corroborated in a Farr-type radio-active hapten binding assay. Specificity of labelling with ferritin was established by immunoelectron microscopic controls, and by the excellent correlation between specific labelling of cells with ferritin and the particular peptidoglycan primary structure of bacterial strains investigated. Cells of Lactobacillus gasseri, Streptococcus pyogenes and Staphylococcus aureus revealing non-crosslinked peptide subunit pentapeptides in their peptidoglycans could specifically be labelled. Lactobacillus acidophilus and Bacillus subtilis, on the contrary, missing such pentapeptides, failed in labelling.The implication of this method to possibly localize the points of attack of penicillin or cycloserine is discussed.Abbreviations used meso-A2pm
meso-diaminopimelic acid
- DSM
Deutsche Sammlung für Mikroorganismen, Göttingen, FRG
This paper is dedicated to Professor Gerhart Drews on the occasion of his 60th birthday 相似文献
3.
The effect of glucose on the expression of extracellular protein genes by Staphylococcus aureus strain V8 总被引:2,自引:0,他引:2
The bacteria from overnight cultures (20 h) of S. aureus V8 and exp negative mutant K6812-1, grown, aerobically, in 3% (w/v) Tryptone Soya Broth, at 37 degrees C, were resuspended in fresh medium, in the case of the parent strain +/- 1% (w/v) glucose, without change in bacterial density. During a 6 h incubation period there was an approximate doubling of bacterial density, to the same level, in each case. However, exoprotein production by the mutant was only 20% that of the parent whilst the addition of glucose to the V8 strain resulted in a tenfold reduction in the exoprotein formed. SDS-polyacrylamide gel electrophoresis showed that the exoprotein patterns of both organisms after 6 h incubation were the same as those observed in the overnight cultures whilst the presence of 1% (w/v) extra glucose changed the pattern produced by the parent to one similar to that of the mutant. The results showed that conditions which lead to the rapid formation of glucose catabolites produced an effect consistent with the inhibition of the activity of the exp gene product. 相似文献
4.
Stefan Evers Barbara Casadewall Murielle Charles Sylvie Dutka-Malen Marc Galimand Patrice Courvalin 《Journal of molecular evolution》1996,42(6):706-712
Thed-alanine:d-alanine-ligase-related enzymes can have three preferential substrate specificities. Usually, these enzymes synthesized-alanyl-d-alanine. In vancomycin-resistant Gram-positive bacteria, structurally related enzymes synthesized-alanyl-d-lactate or Dalanyl-d-serine. The sequence of internal fragments of eight structurald-alanine:d-alanine ligase genes from enterococci has been determined. Alignment of the deduced amino acid sequences with those of other
related enzymes from Gram-negative and Gram-positive bacteria revealed the presence of four distinct sequence patterns in
the putative substrate-binding sites, each correlating with specificity to a particular substrate (d-alanine:d-lactate ligases exhibited two patterns). Phylogenetic analysis showed different clusters. The enterococcal subtree was largely
superimposable on that derived from 16S rRNA sequences. In lactic acid bacteria, structural divergence due to differences
in substrate specificity was observed. Glycopeptide resistance proteins VanA and VanB, the VanC-type ligases, and Dd1A and
DdlB from enteric bacteria andHaemophilus influenzae constituted separate clusters.
Correspondence to: P. Courvalin 相似文献
5.
The prevalence of gentamicin 2'-N-acetyltransferase in the Proteeae and its role in the O-acetylation of peptidoglycan 总被引:1,自引:0,他引:1
Abstract The prevalence of aac(2')-Ia , a gene coding for gentamicin 2'-JV-acetyltransferase in Providenda stuartii , among species of the Proteeae was investigated to determine if it is a common resistance factor and whether the correlation observed in P. stuartii between its expression and the levels of peptidoglycan O -acetylation represents a general feature of bacteria producing this form of modified peptidoglycan. An evaluation of the MICs of gentamicin for each of the species of the Proteeae did not reveal any apparent relationship between resistance and the degree of O-acetylation of peptidoglycan. The entire aac(2')-Ia gene was used as a probe in Southern hybridization experiments against genomic DNA from each species of the Proteeae. A sequence with strong homology to aac(2')-Ia was present only in Proteus penneri while weak hybridization was also observed to the restriction digested DNA from Providenda rettgeri . Other bacteria that O -acetylate peptidoglycan were also screened with this probe and a homologous DNA sequence was only found in Neisseria subflava . These data suggest that AAC(2')-Ia may contribute to the rO -acetylation of peptidoglycan in P. stuartii , but a more specific enzyme must also be produced for this function. 相似文献
6.
E. M. Tul'skaya G. M. Streshinskaya I. B. Naumova A. S. Shashkov L. P. Terekhova 《Archives of microbiology》1993,160(4):299-305
The cell-wall teichoic acids of Nocardiopsis dassonvillei IMRU 509T, IMRU 504 and IMRU 1250 and Nocardiopsis antarctius VKM Ac-836T have the same unique structure that has not heretofore been found in bacteria. The polymer is built of 10 to 13 repeating units:
相似文献
7.
《Saudi Journal of Biological Sciences》2023,30(8):103730
Mycobacterium tuberculosis (MTB) is becoming more and more resistant to drugs and it is a common problem, making current antimicrobials ineffective and highlighting the need for new TB drugs. One of the promising targets for treating MTB is MurB enzymes. This study aimed to identify potential inhibitors of MurB enzymes in M. tuberculosis, as drug resistance among MTB is a significant problem. Attempts are being made to conduct a virtual screening of 30,417 compounds, and thirty-two compounds were chosen for further analysis based on their binding conformations. The selected compounds were assessed for their drug-likeness, pharmacokinetics, and physiochemical characteristics, and seven compounds with binding energy lower than flavin (FAD) were identified. Further, molecular dynamics simulation analysis of these seven compounds found that four of them, namely DB12983, DB15688, ZINC084726167, and ZINC254071113 formed stable complexes with the MurB binding site, exhibiting promising inhibitory activity. These compounds have not been mentioned in any other study, indicating their novelty. The study suggests that these four compounds could be promising candidates for treating MTB, but their effectiveness needs to be validated through in vitro and in vivo experiments. Overall, the findings of this study provide new insight into potential drug targets and candidates for combating drug-resistant MTB. 相似文献
8.
Abstract Cells of isolates of Thermus from hot springs in New Zealand were tested for the composition of peptidoglycan, the occurrence of respiratory quinones and the mean base composition of DNA. The DNA: DNA homology was tested by the filter hybridisation and spectrophotometric reassociation rate methods. Thermus filiformis and non-filamentous strains isolated from New Zealand hot springs show great homogeneity, and have low DNA: DNA homology with the species Thermus aquaticus , ' Thermus thermophilus' , and a new genospecies, Thermus brockianus . 相似文献
9.
Degradation of soluble collagen by ozone or hydroxyl radicals 总被引:4,自引:0,他引:4
Collagen exposed to ozone or hydroxyl radicals was degraded in a time- and dose-dependent manner. This degradation was inhibited by free radical scavengers. Furthermore, lower levels of these oxidants did not degrade the molecule, but caused it to become susceptible to proteolytic degradation. We suggest an alternative mechanism by which oxygen-derived free radicals participate in the destruction of extracellular matrix observed during acute lung injury by oxidant gas, in addition to the commonly accepted proteinase-antiproteinase theory of lung injury. 相似文献
10.
An enzyme was identified in human serum which unlike lysozyme cleaved the amide bond between N-acetyl-muramic acid and l-alanine of the peptide side chain of the rigid layer (murein) of Escherichia coli. The N-acetylmuramyl-l-alanine amidase released all of the peptide side chains including those to which the lipoprotein is bound. A portion of the peptide side chains of the Micrococcus lysodeikticus murein was also hydrolysed from the polysaccharide chains. E. coli, M. lysodeikticus, Bacillus subtilis and Staphylococcus aureus were not killed by the amidase. Treatment of E. coli with EDTA or osmotic shock rendered the cells sensitive to the amidase and they were killed. Possible biological functions of the amidase are discussed.The enzyme was separated from lysozyme in human serum. Gel permeation chromatography indicated a molecular weight of the active enzyme of 82,000 while gel electrophoresis in the presence of sodium dodecyl sulfate revealed a molecular weight of 75,000. Thus, the enzyme probably consists of a single polypeptide chain. Incubation with neuraminidase rendered the amidase more basic suggesting the release of sialic acid residues. The modified glycoprotein disclosed an increased activity to murein. Enzyme activity was inhibited by p-chloromercuribenzene sulfonate and ethyleneglycol-bis(2-aminomethyl) tetraacetate (EGTA) at 1 and 0.2 mM concentration, respectively, whereas EDTA up to 5 mM was without effect. The amidase was also inactivated by agents that reduce disulfide bridges. 相似文献
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