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J Gagnaire O Dauwalder S Boisset D Khau AM Freydière F Ader M Bes G Lina A Tristan ME Reverdy A Marchand T Geissmann Y Benito G Durand JP Charrier J Etienne M Welker A Van Belkum F Vandenesch 《PloS one》2012,7(7):e40660
The aim of the present study was to detect the Staphylococcus aureus delta-toxin using Whole-Cell (WC) Matrix Assisted Laser Desorption Ionization-Time-of-Flight (MALDI-TOF) mass spectrometry (MS), correlate delta-toxin expression with accessory gene regulator (agr) status, and assess the prevalence of agr deficiency in clinical isolates with and without resistance to methicillin and glycopeptides. The position of the delta-toxin peak in the mass spectrum was identified using purified delta-toxin and isogenic wild type and mutant strains for agr-rnaIII, which encodes delta-toxin. Correlation between delta-toxin production and agr RNAIII expression was assessed by northern blotting. A series of 168 consecutive clinical isolates and 23 unrelated glycopeptide-intermediate S. aureus strains (GISA/heterogeneous GISA) were then tested by WC-MALDI-TOF MS. The delta-toxin peak was detected at 3005±5 Thomson, as expected for the naturally formylated delta toxin, or at 3035±5 Thomson for its G10S variant. Multivariate analysis showed that chronicity of S. aureus infection and glycopeptide resistance were significantly associated with delta-toxin deficiency (p?=?0.048; CI 95%: 1.01-10.24; p?=?0.023; CI 95%: 1.20-12.76, respectively). In conclusion, the S. aureus delta-toxin was identified in the WC-MALDI-TOF MS spectrum generated during routine identification procedures. Consequently, agr status can potentially predict infectious complications and rationalise application of novel virulence factor-based therapies. 相似文献
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Odds FC Bougnoux ME Shaw DJ Bain JM Davidson AD Diogo D Jacobsen MD Lecomte M Li SY Tavanti A Maiden MC Gow NA d'Enfert C 《Eukaryotic cell》2007,6(6):1041-1052
We analyzed data on multilocus sequence typing (MLST), ABC typing, mating type-like locus (MAT) status, and antifungal susceptibility for a panel of 1,391 Candida albicans isolates. Almost all (96.7%) of the isolates could be assigned by MLST to one of 17 clades. eBURST analysis revealed 53 clonal clusters. Diploid sequence type 69 was the most common MLST strain type and the founder of the largest clonal cluster, and examples were found among isolates from all parts of the world. ABC types and geographical origins showed statistically significant variations among clades by univariate analysis of variance, but anatomical source and antifungal susceptibility data were not significantly associated. A separate analysis limited to European isolates, thereby minimizing geographical effects, showed significant differences in the proportions of isolates from blood, commensal carriage, and superficial infections among the five most populous clades. The proportion of isolates with low antifungal susceptibility was highest for MAT homozygous a/a types and then alpha/alpha types and was lowest for heterozygous a/alpha types. The tree of clades defined by MLST was not congruent with trees generated from the individual gene fragments sequenced, implying a separate evolutionary history for each fragment. Analysis of nucleic acid variation among loci and within loci supported recombination. Computational haplotype analysis showed a high frequency of recombination events, suggesting that isolates had mixed evolutionary histories resembling those of a sexually reproducing species. 相似文献
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Colette Hindelang-Gertner Dr. Marie-Elisabeth Stoeckel Aimé Porte Fred Stutinsky 《Cell and tissue research》1976,170(1):17-41
Summary The morphological effects of colchicine on the entire neurosecretory (NS) tract and on various hypothalamic nuclei have been studied. The perturbation in axonal flow, indicated by the accumulation of NS material, coincide with fragmentation of the cytoplasmic membranes, i. e. the Golgi apparatus and the endoplasmic reticulum, whereas the neurotubules remain relatively well preserved. Autophagic destruction of NS material is observed along the entire length of the NS fibres. The rapid and systematic changes in the axoplasmic reticulum, known to store calcium, lead us to envisage a role for this system — similar to that of the sarcoplasmic reticulum — in controlling the transport of NS vesicles. The junctional zone between the stalk and the neural lobe seems to play a particular rôle in the transport of NS material to the posthypophysial terminals of the NS axons. Colchicine provokes an increase in dense-cored vesicles in most of the neurons of the other hypothalamic nuclei studied: arcuate, suprachiasmatic, periventricular and ventromedial. Membranous alterations are also observed in these sites. Colchicine administered to animals which were hypothyroid, castrated or adrenalectomized, reveals stimulated neurons, identified by their excessive content of dense-cored vesicles. These neurons display no specific localization, for they occur in all hypothalamic nuclei, irrespective of the stimulation. The frequency of stimulation of neurons of the periventricular nucleus is striking. 相似文献
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Petavy AF Hormaeche C Lahmar S Ouhelli H Chabalgoity A Marchal T Azzouz S Schreiber F Alvite G Sarciron ME Maskell D Esteves A Bosquet G 《PLoS neglected tropical diseases》2008,2(1):e125
Dogs are the main source of human cystic echinococcosis. An oral vaccine would be an important contribution to control programs in endemic countries. We conducted two parallel experimental trials in Morocco and Tunisia of a new oral vaccine candidate against Echinococcus granulosus in 28 dogs. The vaccine was prepared using two recombinant proteins from adult worms, a tropomyosin (EgTrp) and a fibrillar protein similar to paramyosin (EgA31), cloned and expressed in a live attenuated strain of Salmonella enterica serovar typhimurium.In each country, five dogs were vaccinated with the associated EgA31 and EgTrp; three dogs received only the vector Salmonella; and six dogs were used as different controls. The vaccinated dogs received two oral doses of the vaccine 21 d apart, and were challenged 20 d later with 75,000 living protoscoleces. The controls were challenged under the same conditions. All dogs were sacrificed 26-29 d postchallenge, before the appearance of eggs, for safety reasons.We studied the histological responses to both the vaccine and control at the level of the duodenum, the natural localization of the cestode. Here we show a significant decrease of parasite burden in vaccinated dogs (70% to 80%) and a slower development rate in all remaining worms. The Salmonella vaccine EgA31-EgTrp demonstrated a high efficacy against E. granulosus promoting its potential role in reducing transmission to humans and animals. 相似文献
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Bouma Marie-Elisabeth Rogier Edith Verthier Nicole Labarre Colette Feldmann Gérard 《In vitro cellular & developmental biology. Plant》1989,25(3):267-275
Summary The hepatoblastoma cell line HepG2 has been a matter of many investigations; most of them include biochemical studies of lipoprotein
and other hepatic protein metabolism. However, the accurate cellular features of these cells have not been emphasized. We
studied the cellular histologic, histochemical, and ultrastructural characteristics of this cell line. In addition, we investigated
by immunoenzymatic methods the cellular biosynthesis of several proteins: apolipoproteins-AI,-B,-D, and-E, albumin, alpha-fetoprotein,
transferrin, alpha-1-antitrypsin, C-reactive protein, fibronectin, and collagens I, III and IV. The rates of accumulation, in the medium of HepG2
cells, of albumin, alpha-1-antitrypsin, transferrin, and alpha-fetoprotein were 13.2±1.9; 4.9±1.5; 3.2±0.4; and 10.7±1.7 μg/106 cells/24 h, respectively. Our results show that HepG2 cells exhibited most cellular features of normal human hepatocytes.
Bile canaliculi as well as Golgi apparatus complexes were particularly developed. Except for the C-reactive protein, HepG2
cells have all retained the ability to synthesize hepatic proteins but with some variable intensity from cell to cell. This
hepatoblastoma cell line seems to represent a useful tool in the understanding of hepatic protein biosynthesis, particularly
for the investigation on the secretory pathway of plasma proteins. 相似文献
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Complementation of Saccharomyces cerevisiae auxotrophic mutants by Arabidopsis thaliana cDNAs 总被引:32,自引:0,他引:32
Michéle Minet Marie-Elisabeth Dufour François Lacroute 《The Plant journal : for cell and molecular biology》1992,2(3):417-422
An Arabidopsis thaliana cDNA bank has been constituted in a Saccharomyces cerevisiae expression vector based on the phosphoglycerate kinase (PGK) promoter and terminator. This bank was used to complement eight S. cerevisiae auxotrophic markers. All of them were corrected. These results confirm the quality of the bank and the feasibility of cloning plant genes by yeast mutant complementation. The cDNA complementing the ura1 yeast mutant was sequenced, analysed and shown to encode a dihydroorotic (DHO) dehydrogenase sequence. 相似文献