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561.
Detection of cultured and uncultured Burkholderia cepacia complex bacteria naturally occurring in the maize rhizosphere 总被引:3,自引:0,他引:3
Pirone L Chiarini L Dalmastri C Bevivino A Tabacchioni S 《Environmental microbiology》2005,7(11):1734-1742
The species composition of a Burkholderia cepacia complex population naturally occurring in the maize rhizosphere was investigated by using both culture-dependent and culture-independent methods. B. cepacia complex isolates were recovered from maize root slurry on the two selective media Pseudomonas cepacia azelaic acid tryptamine (PCAT) and trypan blue tetracycline (TB-T) and subjected to identification by a combination of restriction fragment length polymorphism (RFLP) analysis and species-specific polymerase chain reaction (PCR) tests of the recA gene. DNA extracted directly from root slurry was examined by means of nested PCR to amplify recA gene with species-specific B. cepacia complex primers and to obtain a library of PCR amplified recA genes. Using the culture-dependent method the species Burkholderia cepacia, Burkholderia cenocepacia, Burkholderia ambifaria and Burkholderia pyrrocinia were identified, whereas using the culture-independent method also the species Burkholderia vietnamiensis was detected. The latter method also allowed us to highlight a higher diversity within the B. cenocepacia species. In fact, by using the culture-independent method the species B. cenocepacia recA lineages IIIA and IIID besides B. cenocepacia recA lineage IIIB were detected. Moreover, higher heterogeneity of recA RFLP patterns was observed among clones assigned to the species B. cenocepacia than among B. cenocepacia isolates from selective media. 相似文献
562.
Ben Hamed K Ben Youssef N Ranieri A Zarrouk M Abdelly C 《Journal of plant physiology》2005,162(5):599-602
In the halophyte Crithmum maritimum, the sulfolipid content increased considerably in the presence of NaCl. There were no significant changes in the total fatty acid composition of sulfolipids during salt treatment, except for linoleic and linolenic acids. In comparison to the control plants, sulfolipids in NaCl-treated plants showed a decrease in the percentage of unsaturated fatty acid (C18:3), and a corresponding increase in the percentage of unsaturated fatty acids (C18:2). As a whole, the data reported in this work suggest that sulfolipds may be one important aspect of strategies involved in salt tolerance of this halophyte. 相似文献
563.
Gustavino B Buschini A Monfrinotti M Rizzoni M Tancioni L Poli P Rossi C 《Mutation research》2005,587(1-2):103-113
The use of chlorinated disinfectants during drinking-water production has been shown to generate halogenated compounds as a result of interactions of humic acids with chlorine. Such chlorinated by-products have been shown to induce genotoxic effects and consumption of chlorinated drinking-water has been correlated with increased risk for cancer induction in human populations. The aim of this work was to test the potential genotoxic effects on circulating erythrocytes of the fish Cyprinus carpio exposed in vivo to well-waters disinfected with sodium hypochlorite (NaClO), chlorine dioxide (ClO2) or peracetic acid (CH3COO2H, PAA), in the absence or presence of standard humic acids (HA). The effects were measured by use of the micronucleus (MN) and the single-cell gel electrophoresis (Comet) assays at different sampling times after a 3-day exposure period. The exposure to chlorine disinfectants without the addition of HA produced a clear toxic effect. Significant cytogenetic damage (i.e. MN induction) was detected in fish populations exposed to both NaClO and ClO2 with humic acids. In the Comet assay, a significant decrease of DNA migration was observed in erythrocytes of specimens after exposure to NaClO-disinfected water without HA. No effects were observed in any other experimental condition. 相似文献
564.
Undersulfated, low-molecular-weight glycol-split heparin as an antiangiogenic VEGF antagonist 总被引:4,自引:0,他引:4
Pisano C Aulicino C Vesci L Casu B Naggi A Torri G Ribatti D Belleri M Rusnati M Presta M 《Glycobiology》2005,15(2):1C-6C
Vascular endothelial growth factor (VEGF) represents a target for antiangiogenic therapies in a wide spectrum of diseases, including cancer. As a novel strategy to generate nonanticoagulant antiangiogenic substances exploiting binding to VEGF while preventing receptor engagement, we assessed the VEGF-antagonist activity of a low-molecular-weight (LMW) compound (ST2184, Mw = 5800) generated by depolymerization of an undersulfated glycol-split heparin derivative. The parental compound was obtained by introducing regular sulfation gaps along the prevalently N-sulfated heparin regions, followed by glycol-splitting of all nonsulfated uronic acid residues (approximately 50% of total uronic acid residues). ST2184 was endowed with a negligible anticoagulant activity after S.C. injection in mice. ST2184 binds VEGF165 as evaluated by its capacity to retard 125I-VEGF165 electrophoretic migration in a gel mobility shift assay and to prevent VEGF165 interaction with heparin immobilized onto a BIAcore sensor chip. Unlike heparin, ST2184 was unable to present 125I-VEGF165 to its high-affinity receptors in endothelial cells and inhibited VEGF165-induced neovascularization in the chick embryo chorioallantoic membrane. Undersulfated, LMW glycol-split heparins may therefore provide the basis for the design of novel nonanticoagulant angiostatic compounds. 相似文献
565.
Alisi C Lasinio GJ Dalmastri C Sprocati A Tabacchioni S Bevivino A Chiarini L 《Microbial ecology》2005,50(3):385-395
Burkholderia cenocepacia, Burkholderia ambifaria, and Burkholderia pyrrocinia are the Burkholderia cepacia complex (Bcc) species most frequently associated with roots of crop plants. To investigate the ecophysiological diversity
of these species, metabolic profiling of maize rhizosphere isolates was carried out by means of the Biolog system, using GN2
and SFN2 plates and different parameters related to optical density (OD). The metabolic profiles produced by the SFN2 and
GN2 plates were identical, but the SFN2's narrower range of OD values and significantly longer reaction times made these plates
less suitable for differentiation of isolates. Principal component analysis of maximum OD (ODM) and maximum substrate oxidation rate (μM) data generated by GN2 plates allowed the selection of a reduced number of carbon sources. Statistical analysis of ODM values highlighted marked differences between the metabolic profiles of B. cenocepacia and B. ambifaria, whereas metabolic profiles of B. pyrrocinia clustered very often with those of B. cenocepacia. Analysis of the μM parameter resulted in a slightly lower differentiation among the three Bcc species and a higher metabolic diversity within
the single species, in particular within B. cenocepacia. Finally, B. cenocepacia and B. pyrrocinia showed generally higher oxidation rates than B. ambifaria on those GN2 substrates that commonly occur in maize root exudates. 相似文献
566.
Inhibition of c-Myc oncoprotein limits the growth of human melanoma cells by inducing cellular crisis 总被引:2,自引:0,他引:2
Biroccio A Amodei S Antonelli A Benassi B Zupi G 《The Journal of biological chemistry》2003,278(37):35693-35701
567.
Biroccio A Benassi B Filomeni G Amodei S Marchini S Chiorino G Rotilio G Zupi G Ciriolo MR 《The Journal of biological chemistry》2002,277(46):43763-43770
The objective of this article is to dissect the mechanisms by which the down-regulation of c-Myc induces programmed cell death in melanoma cells. In stable and doxycycline-inducible M14 melanoma cells, down-regulation of c-Myc induced apoptosis subsequent to a decrease in the intracellular reduced glutathione content and a concomitant accumulation of its oxidized form. This redox alteration was associated with a decrease of the enzyme activities of gamma-glutamyl-cysteine synthetase and NADPH-dependent GSSG reductase, as well as a consequent glutathione release in the extracellular medium. Cytochrome c was released into the cytosol at very early stages of apoptosis induction, long before detectable production of reactive oxygen species and activation of caspase-9 and -3. Macroarray analysis revealed that down-regulation of c-Myc produced striking changes in gene expression in the section related to metabolism, where the expression of gamma-glutamyl-cysteine synthetase and GSSG reductase was found to be significantly reduced. The addition of N-acetyl-l-cysteine or glutathione ethyl ester inhibited the apoptotic process, thus confirming the key role of glutathione in programmed cell death induced by c-Myc. 相似文献
568.
Biodegradation of Hexahydro-1,3,5-Trinitro-1,3,5-Triazine and Its Mononitroso Derivative Hexahydro-1-Nitroso-3,5-Dinitro-1,3,5-Triazine by Klebsiella pneumoniae Strain SCZ-1 Isolated from an Anaerobic Sludge 总被引:1,自引:0,他引:1 下载免费PDF全文
Jian-Shen Zhao Annamaria Halasz Louise Paquet Chantale Beaulieu Jalal Hawari 《Applied microbiology》2002,68(11):5336-5341
In previous work, we found that an anaerobic sludge efficiently degraded hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), but the role of isolates in the degradation process was unknown. Recently, we isolated a facultatively anaerobic bacterium, identified as Klebsiella pneumoniae strain SCZ-1, using MIDI and the 16S rRNA method from this sludge and employed it to degrade RDX. Strain SCZ-1 degraded RDX to formaldehyde (HCHO), methanol (CH3OH) (12% of total C), carbon dioxide (CO2) (72% of total C), and nitrous oxide (N2O) (60% of total N) through intermediary formation of methylenedinitramine (O2NNHCH2NHNO2). Likewise, hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX) was degraded to HCHO, CH3OH, and N2O (16.5%) with a removal rate (0.39 μmol·h−1·g [dry weight] of cells−1) similar to that of RDX (0.41 μmol·h−1·g [dry weight] of cells−1) (biomass, 0.91 g [dry weight] of cells·liter−1). These findings suggested the possible involvement of a common initial reaction, possibly denitration, followed by ring cleavage and decomposition in water. The trace amounts of MNX detected during RDX degradation and the trace amounts of hexahydro-1,3-dinitroso-5-nitro-1,3,5-triazine detected during MNX degradation suggested that another minor degradation pathway was also present that reduced —NO2 groups to the corresponding —NO groups. 相似文献
569.
The physiological role of the nonspecific DNA-binding protein Sso7d from the crenarchaeon Sulfolobus solfataricus is unknown. In vitro studies have shown that Sso7d promotes annealing of complementary DNA strands (Guagliardi et al. 1997), induces negative supercoiling (Lopez-Garcia et al. 1998), and chaperones the disassembly and renaturation of protein aggregates in an ATP hydrolysis-dependent manner (Guagliardi et al. 2000). In this study, we examined the relationships among the binding of Sso7d to double-stranded DNA, its interaction with protein aggregates, and its ATPase activity. Experiments with 1-anilinonaphthalene-8-sulfonic acid as probe demonstrated that exposed hydrophobic surfaces in Sso7d are responsible for interactions with protein aggregates and double-stranded DNA, whereas the site of ATPase activity has a non-hydrophobic character. The interactions of Sso7d with double-stranded DNA and with protein aggregates are mutually exclusive events, suggesting that the disassembly activity and the DNA-related activities of Sso7d may be competitive in vivo. In contrast, the hydrolysis of ATP by Sso7d is independent of the binding of Sso7d to double-stranded DNA or protein aggregates. 相似文献