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61.
Pauwels B Korst AE Andriessen V Baay MF Pattyn GG Lambrechts HA Pooter CM Lardon F Vermorken JB 《Radiation research》2005,164(5):642-650
Gemcitabine has excellent radiosensitizing properties, as shown in both preclinical and clinical studies. Radiosensitization correlated with the early S-phase block of gemcitabine. In the present study, we investigated the role of TP53 in the radiosensitizing effect of gemcitabine. Isogenic A549 cells differing in TP53 status were treated with gemcitabine during the 24 h prior to irradiation. Cell survival was determined 7 days after irradiation by the sulforhodamine B test. In addition, cell cycle perturbation was determined by flow cytometry and TP53 expression by Western blot analysis. Gemcitabine caused a concentration-dependent radiosensitizing effect in all cell lines. Transformed A549 cells were less sensitive to the cytotoxic effect of gemcitabine. The cell cycle arrest early in the S phase was dependent on the drug dose but was comparable in the different cell lines and was not related to functional TP53. Using isogenic cell lines, we have shown that neither TP53 status nor the transfection procedure influenced the radiosensitizing effect of gemcitabine. Since both the radiosensitizing effect at equitoxic concentrations and the cell cycle effect of gemcitabine were independent of TP53 expression, it is likely that TP53 protein does not play a crucial role in the radiosensitizing mechanism of gemcitabine. 相似文献
62.
Ivanova EP Onyshchenko OM Christen R Zhukova NV Lysenko AM Shevchenko LS Buljan V Hambly B Kiprianova EA 《Systematic and applied microbiology》2005,28(2):131-136
A slightly creamy, melanogenic, gram-negative, aerobic bacterium was isolated from seawater sample collected in the Karadag Natural Reserve of the Eastern Crimea, the Black Sea. The novel organism was chemoorganotrophic, had no obligate requirement in NaCl, tolerated to 12% NaCl, grew between 10 and 45 degrees C, was slightly alkaliphilic, and was not able to degrade starch, gelatin, agar, and Tween 80. 16S rRNA gene sequence-based analyses of the new organism revealed that Oceanimonas doudoroffii ATCC 27123T, Oceanimonas baumanii ATCC 700832T, and Oceanisphaera litoralis DSM 15406T were the closest relatives (similarity around 97%-96%). The G + C content of the DNA of the strain 31-13T was 55.5mol%. Phosphatidylethanolamine (49.0%), phosphatidylglycerol (41.8%), and diphosphatidylglycerol (9.2%) were the predominant phospholipids. The major fatty acids were 16:0 (24.1%), 16:1omega7 (40.3%), and 18:1omega7 (29.2%). On the basis of the significant differences demonstrated in the phenotypic and chemotaxonomic characteristics, it is suggested that the bacterium be classified as a novel species; the name Oceanimonas smirnovii sp. nov. is proposed. The type strain is 31-13T (UCM B-11076T = LMG 22147T = ATCC BAA-899T). 相似文献
63.
Höfle MG Flavier S Christen R Bötel J Labrenz M Brettar I 《Environmental microbiology》2005,7(5):670-675
16S rRNA-based fingerprinting techniques allow rapid analyses of overall bacterial community structure but suffer from a lack of phylogenetic information hitherto retrievable from the short 16S rRNA gene sequences obtained from excised bands. An approach is presented that allows nearly complete 16S rRNA gene sequences to be retrieved for abundant components of the bacterial community as obtained by the community fingerprint, i.e. those reflected by major fingerprint bands. This was achieved by designing a pair of highly specific primers derived from the sequence of an excised band. Combined with universal 16S rRNA primers, these specific primers were applied directly to environmental DNA serving as template. This procedure allowed the generation of a nearly complete 16S rRNA gene sequence of the target taxon by specific polymerase chain reaction (PCR) followed by cycle sequencing down to a relative abundance of at least 1.5% of the environmental DNA. The procedure was exemplified for an epsilonproteobacterium related to Thiomicrospira denitrificans occurring in the central Baltic Sea. This approach is based only on PCR without any cloning step involved. It allows focussing on specific target taxa and is thus rather efficient. This approach should be applicable in general to 16S rRNA or 16S rRNA gene-based fingerprinting techniques and their respective environmental DNA. 相似文献
64.
Böttcher T Ren H Goiny M Gerber J Lykkesfeldt J Kuhnt U Lotz M Bunkowski S Werner C Schau I Spreer A Christen S Nau R 《Journal of neurochemistry》2004,91(6):1450-1460
In animal models of Streptococcus pneumoniae meningitis, rifampin is neuroprotective in comparison to ceftriaxone. So far it is not clear whether this can be generalized for other protein synthesis-inhibiting antimicrobial agents. We examined the effects of the bactericidal protein synthesis-inhibiting clindamycin (n = 12) on the release of proinflammatory bacterial components, the formation of neurotoxic compounds and neuronal injury compared with the standard therapy with ceftriaxone (n = 12) in a rabbit model of pneumococcal meningitis. Analysis of the CSF and histological evaluation were combined with microdialysis from the hippocampal formation and the neocortex. Compared with ceftriaxone, clindamycin reduced the release of lipoteichoic acids from the bacteria (p = 0.004) into the CSF and the CSF leucocyte count (p = 0.011). This led to lower extracellular concentrations of hydroxyl radicals (p = 0.034) and glutamate (p = 0.016) in the hippocampal formation and a subsequent reduction of extracellular glycerol levels (p = 0.018) and neuronal apoptosis in the dentate gyrus (p = 0.008). The present data document beneficial effects of clindamycin compared with ceftriaxone on various parameters linked with the pathophysiology of pneumococcal meningitis and development of neuronal injury. This study suggests neuroprotection to be a group effect of bactericidal protein synthesis-inhibiting antimicrobial agents compared with the standard therapy with beta-lactam antibiotics in meningitis. 相似文献
65.
Golinelli-Pimpaneau B Lüthi C Christen P 《The Journal of biological chemistry》2006,281(33):23969-23977
Antibody 15A9, raised with 5'-phosphopyridoxyl (PPL)-N(epsilon)-acetyl-L-lysine as hapten, catalyzes the reversible transamination of hydrophobic D-amino acids with pyridoxal 5'-phosphate (PLP). The crystal structures of the complexes of Fab 15A9 with PPL-L-alanine, PPL-D-alanine, and the hapten were determined at 2.3, 2.3, and 2.5A resolution, respectively, and served for modeling the complexes with the corresponding planar imine adducts. The conformation of the PLP-amino acid adduct and its interactions with 15A9 are similar to those occurring in PLP-dependent enzymes, except that the amino acid substrate is only weakly bound, and, due to the immunization and selection strategy, the lysine residue that covalently binds PLP in these enzymes is missing. However, the N-acetyl-L-lysine moiety of the hapten appears to have selected for aromatic residues in hypervariable loop H3 (Trp-H100e and Tyr-H100b), which, together with Lys-H96, create an anion-binding environment in the active site. The structural situation and mutagenesis experiments indicate that two catalytic residues facilitate the transamination reaction of the PLP-D-alanine aldimine. The space vacated by the absent L-lysine side chain of the hapten can be filled, in both PLP-alanine aldimine complexes, by mobile Tyr-H100b. This group can stabilize a hydroxide ion, which, however, abstracts the C alpha proton only from D-alanine. Together with the absence of any residue capable of deprotonating C alpha of L-alanine, Tyr-H100b thus underlies the enantiomeric selectivity of 15A9. The reprotonation of C4' of PLP, the rate-limiting step of 15A9-catalyzed transamination, is most likely performed by a water molecule that, assisted by Lys-H96, produces a hydroxide ion stabilized by the anion-binding environment. 相似文献
66.
67.
Background
High throughput technologies often require the retrieval of large data sets of sequences. Retrieval of EMBL or GenBank entries using keywords is easy using tools such as ACNUC, Entrez or SRS, but has some limitations, in particular when querying with complex keywords. 相似文献68.
Köck R Loth B Köksal M Schulte-Wülwer J Harlizius J Friedrich AW 《Applied and environmental microbiology》2012,78(11):4046-4047
Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) is frequently transmitted from pigs to farmers. This study analyzed whether an absence from direct contact with pigs during holidays had an impact on nasal MRSA colonization rates of pig farmers. Overall, 59% of the farmers did not clear MRSA colonization during their leave. 相似文献
69.
70.
Bea Vuylsteke Gis��le Semd�� Lazare Sika Tania Crucitti Virginie Etti��gne Traor�� Anne Buv�� Marie Laga 《PloS one》2012,7(3)