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221.
Fabrini R Bocedi A Dawood KF Turella P Stella L Parker MW Pedersen JZ Federici G Antonini G Ricci G 《FEBS letters》2011,585(2):341-345
Glutathione transferase reaches 0.5–0.8 mM concentration in the cell so it works in vivo under the unusual conditions of, [S] ? [E]. As glutathione transferase lowers the pKa of glutathione (GSH) bound to the active site, it increases the cytosolic concentration of deprotonated GSH about five times and speeds its conjugation with toxic compounds that are non-typical substrates of this enzyme. This acceleration becomes more efficient in case of GSH depletion and/or cell acidification. Interestingly, the enzymatic conjugation of GSH to these toxic compounds does not require the assumption of a substrate–enzyme complex; it can be explained by a simple bimolecular collision between enzyme and substrate. Even with typical substrates, the astonishing concentration of glutathione transferase present in hepatocytes, causes an unusual “inverted” kinetics whereby the classical trends of v versus E and v versus S are reversed. 相似文献
222.
Rossi F Khanduja JS Bortoluzzi A Houghton J Sander P Güthlein C Davis EO Springer B Böttger EC Relini A Penco A Muniyappa K Rizzi M 《Nucleic acids research》2011,39(16):7316-7328
Mycobacterium tuberculosis is an extremely well adapted intracellular human pathogen that is exposed to multiple DNA damaging chemical assaults originating from the host defence mechanisms. As a consequence, this bacterium is thought to possess highly efficient DNA repair machineries, the nucleotide excision repair (NER) system amongst these. Although NER is of central importance to DNA repair in M. tuberculosis, our understanding of the processes in this species is limited. The conserved UvrABC endonuclease represents the multi-enzymatic core in bacterial NER, where the UvrA ATPase provides the DNA lesion-sensing function. The herein reported genetic analysis demonstrates that M. tuberculosis UvrA is important for the repair of nitrosative and oxidative DNA damage. Moreover, our biochemical and structural characterization of recombinant M. tuberculosis UvrA contributes new insights into its mechanism of action. In particular, the structural investigation reveals an unprecedented conformation of the UvrB-binding domain that we propose to be of functional relevance. Taken together, our data suggest UvrA as a potential target for the development of novel anti-tubercular agents and provide a biochemical framework for the identification of small-molecule inhibitors interfering with the NER activity in M. tuberculosis. 相似文献
223.
Tocci N Simonetti G D'Auria FD Panella S Palamara AT Valletta A Pasqua G 《Applied microbiology and biotechnology》2011,91(4):977-987
Hypericum perforatum is a well-known medicinal plant which contains a wide variety of metabolites, including xanthones, which have a wide range
of biological properties, including antifungal activity. In the present study, we evaluated the capability of roots regenerated
from calli of H. perforatum subsp. angustifolium to produce xanthones. Root biomass was positively correlated with the indole-3-butyric acid concentration, whereas a concentration
of 1 mg l−1 was the most suitable for the development of roots. High auxin concentrations also inhibited xanthone accumulation. Xanthones
were produced in large amounts, with a very stable trend throughout the culture period. When the roots were treated with chitosan,
the xanthone content dramatically increased, peaking after 7 days. Chitosan also induced a release of these metabolites into
the culture. The maximum accumulation (14.26 ± 0.62 mg g−1 dry weight [DW]) and release (2.64 ± 0.13 mg g−1 DW) of xanthones were recorded 7 days after treatment. The most represented xanthones were isolated, purified, and spectroscopically
characterized. Antifungal activity of the total root extracts was tested against a broad panel of human fungal pathogen strains
(30 Candida species, 12 Cryptococcus neoformans, and 16 dermatophytes); this activity significantly increased when using chitosan. Extracts obtained after 7 days of chitosan
treatment showed high antifungal activity (mean minimum inhibitory concentration of 83.4, 39.1, and 114 μg ml−1 against Candida spp., C. neoformans, and dermatophytes, respectively). Our results suggest that root cultures can be considered as a potential tool for large-scale
production of extracts with stable quantities of xanthones. 相似文献
224.
The aim of this study was to assess the impact of inoculation of Phaseolus vulgaris with two indigenous rhizobia strains on plant growth promotion, nitrogen turnover processes, richness and structure of the Rhizobiaceae and total bacterial communities in the bulk soil. Both strains used induced a significant increase in nodulation and grain yield. Analysis of bulk soil fertility showed positive, negative and strain-dependent effects of inoculation on nitrate, phosphorus and ammonium, respectively. Terminal-restriction fragment length polymorphism profiling demonstrated that inoculation significantly increased the phylotype richness of the bacterial communities. No significant difference in richness between the strains used and no additive effect of co-inoculation were observed. However, differences between both inoculants and a clear additive effect of co-inoculation on heterogeneity were found. This work gives original insights into the effect of rhizobial inoculation outside the restricted rhizospheric area. Effects on bacterial structure and diversity are clearly sensed in the neighbourhood of 25 cm and in a limited time course. Both Alpha- and Gammaproteobacteria, together with Firmicutes and Actinobacteria, were enhanced by inoculation, No evidence of terminal-restriction fragment inhibition was found. However, it remains to be answered how the impact on taxonomic groups can be related to effects on functional capabilities of soil microbial communities. 相似文献
225.
Fornasin A 《Journal of biosocial science》2011,43(4):453-467
The aim of this study was to identify the characteristics of individuals who formed exogamic marriages in the Friuli region (north-east Italy) during the second half of the 19th century. Logistic regression models were devised to measure the influence of the determinants of exogamic marriage, taking into account not only variables related to context but also spouses' economic, social and cultural characteristics. The determinants of exogamic marriage differ for men and women, and also vary by region due to differences in geographical mobility and size of the marriage market. The majority of exogamic spouses belong to one of two categories: either older individuals, often, especially in the case of men, with a previous marriage; or the upper social classes. 相似文献
226.
Landi D Moreno V Guino E Vodicka P Pardini B Naccarati A Canzian F Barale R Gemignani F Landi S 《Mutation research》2011,717(1-2):109-115
In this review, we focus on the genetic variations (single nucleotide polymorphisms, SNPs) known to occur in microRNAs and in their binding sites and the susceptibility to cancers of the gastro-intestinal (GI) tract in humans. Since the sequence complementarity and the thermodynamics of binding play an essential role in the interaction of miRNA with its target mRNA, sequence variations in the miRNA-binding seed regions or in miRNA genes (either within pre-, pri-, or mature miRNA regions) should reinforce, weaken, or disrupt the miRNA-mRNA interaction and affect the expression of mRNA targets. Indirect evidences supporting these hypotheses are reported in the literature, essentially coming from case-control association studies. Several studies have been published on the association between miR-SNPs or SNPs within their binding sites and the risk of oesophageal, gastric, or colorectal cancer. Unfortunately, functional studies are lacking. Besides reviewing the available literature, we present here for the first time two SNPs (rs17281995 in CD86 and rs1051690 in INSR) previously associated with the risk of CRC in a Czech population are also associated with the risk in a Spanish population. Moreover, we show for the first time that both these alleles regulate differentially the amount of a reporter gene (luciferase) in an in vitro assay on HeLa cells. These findings suggest that both these SNPs may have a functional role in regulating the expression of CD-86 and INSR proteins acting at the level of the 3'UTR. More functional studies are needed in order to better understand the role of polymorphic regulatory sequences at the 3'UTR of genes. 相似文献
227.
Cappellozza S Saviane A Tettamanti G Squadrin M Vendramin E Paolucci P Franzetti E Squartini A 《Journal of invertebrate pathology》2011,106(3):386-393
Enterococcus mundtii was shown to be directly correlated with flacherie disease of the silkworm larvae reared on artificial diet supplemented with chloramphenicol. Its identification was carried out by means of light and electron microscopy and nucleotide sequencing of 16S gene. The bacterium is capable of rapidly multiplying in the silkworm gut and of invading other body tissues, as demonstrated by deliberate infection of germfree larvae and by subsequent TEM observations. E. mundtii can endure alkaline pH of the silkworm gut and it has been proved to adapt in vitro to commonly applied doses of chloramphenicol, whose use can further contribute to reduce competition by other bacteria in Bombyx mori alimentary canal.The modality of transmission of the infection to the larvae was among the objectives of the present research. Since contamination of the progeny by mother moths can be avoided through routine egg shell disinfection, a trans-ovarian vertical transmission can be ruled out. On the other hand the bacterium was for the first time identified on mulberry leaves, and therefore artificial diet based on leaf powder could be a source of infection. We showed that while microwaved diet could contain live E. mundtii cells, the autoclaved diet is safe in this respect. Being E. mundtii also part of the human-associated microbiota, and since B. mori is totally domestic species, a possible role of man in its epidemiology can be postulated. 相似文献
228.
Gamma proteobacteria can nodulate legumes of the genus Hedysarum 总被引:1,自引:0,他引:1
Benhizia Y Benhizia H Benguedouar A Muresu R Giacomini A Squartini A 《Systematic and applied microbiology》2004,27(4):462-468
The bacteria hosted in the root nodules of the three Mediterranean wild legume species Hedysarum carnosum, Hedysarum spinosissimum subsp. capitatum, and Hedysarum pallidum, growing in native stands in different habitats in Algeria were isolated. Bacteria were recovered on yeast-mannitol-agar or on minimal media from a total of 52 nodules. Isolates were analyzed by Amplified Ribosomal DNA Restriction Analysis (ARDRA) using the enzyme CfoI, and further sorted by RAPD fingerprinting. A total of ten different types were found and their amplified 16S rDNA was sequenced and compared to databases. The BLAST alignment indicates that all the species whose sequences share 98 to 100% identity to the bacteria found in these nodules belong to the class Gammaproteobacteria and include Pantoea agglomerans, Enterobacter kobei, Enterobacter cloacae, Leclercia adecarboxylata, Escherichia vulneris, and Pseudomonas sp. No evidence of any rhizobial-like sequence was found even upon amplifying from the bulk of microbial cells obtained from the squashed nodules, suggesting that the exclusive occupants of the nodules formed by the three plants tested are members of the orders Enterobacteriales or Pseudomonadales. This is the first report of Gammaproteobacteria associated with legume nodules. Despite the presence of the related crop plant Hedysarum coronarium, specifically nodulated by Rhizobium sullae, these three Hedysarum species demonstrate to have undergone a separate path in terms of endophytic interactions with bacteria. An hypothesis to account for differences between the symbiotic relationships engaged by man-managed legumes, and those found in plants whose ecology is independent from human action, is discussed. 相似文献
229.
Serena Bugoni Valentina Merlini Alessio Porta Giuseppe Zanoni Giovanni Vidari 《化学与生物多样性》2014,11(10):1540-1553
A novel enantioselective divergent route to 13‐alkyl derivatives of α‐ and γ‐ionone, important components of perfumes and fragrances, is reported. This relatively short and convenient methodology takes advantage of the use of a common intermediate, easily obtained from highly enantiomerically enriched (S)‐α‐ionone, which avoids the separate installation of the butenone side chain at C(6) for each analog. Olfactory evaluation of synthesized compounds reconfirmed the influence of the hydrophobic interactions of alkyl substituents at C(5) with olfactory receptors (ORs) in the chemoreception of ionones, and suggested that a synperiplanar orientation of C(13) and the lateral chain is the better geometry fitting OR's cavity. 相似文献
230.
Daniela Di Giuseppe Alessio Crippa Nicola Orsini Alicja Wolk 《Arthritis research & therapy》2014,16(5)