Search results for "ENTEROBACTERIACEAE"
showing 10 items of 143 documents
Medfly Ceratitis capitata as Potential Vector for Fire Blight Pathogen Erwinia amylovora: Survival and Transmission
2015
Monitoring the ability of bacterial plant pathogens to survive in insects is required for elucidating unknown aspects of their epidemiology and for designing appropriate control strategies. Erwinia amylovora is a plant pathogenic bacterium that causes fire blight, a devastating disease in apple and pear commercial orchards. Studies on fire blight spread by insects have mainly focused on pollinating agents, such as honeybees. However, the Mediterranean fruit fly (medfly) Ceratitis capitata (Diptera: Tephritidae), one of the most damaging fruit pests worldwide, is also common in pome fruit orchards. The main objective of the study was to investigate whether E. amylovora can survive and be tra…
GroEL buffers against deleterious mutations
2002
GroEL, a heat-shock protein that acts as a molecular chaperone1, is overproduced in endosymbiotic but not in free-living bacteria2,3,4, presumably to assist in the folding of conformationally damaged proteins. Here we show that the overproduction of GroEL in Escherichia coli masks the effects of harmful mutations that have accumulated during a simulated process of vertical transmission. This molecular mechanism, which may be an adaptation to the bacterium's intracellular lifestyle, is able to rescue lineages from a progressive fitness decline resulting from the fixation of deleterious mutations under strong genetic drift5,6.
Differential annotation of tRNA genes with anticodon CAT in bacterial genomes.
2006
We have developed three strategies to discriminate among the three types of tRNA genes with anticodon CAT (tRNA(Ile), elongator tRNA(Met) and initiator tRNA(fMet)) in bacterial genomes. With these strategies, we have classified the tRNA genes from 234 bacterial and several organellar genomes. These sequences, in an aligned or unaligned format, may be used for the identification and annotation of tRNA (CAT) genes in other genomes. The first strategy is based on the position of the problem sequences in a phenogram (a tree-like network), the second on the minimum average number of differences against the tRNA sequences of the three types and the third on the search for the highest score value …
A rapid method for the screening of plasmids in transformed yeast strains
1988
A method for the rapid screening of plasmids in yeast cells has been developed. The method is an adaptation of the currently used alkaline lysis methods forEscherichia coli plasmids. Following the conditions described, several dozen ofSaccharomyces cerevisiae-transformed clones can be analyzed for their plasmid content in less than 2 h. The plasmids obtained by this procedure are suitable for restriction analysis or forE. coli andS. cerevisiae transformation.
Characterization of R-plasmids in environmental isolates ofsalmonella: Host range and stability
1988
Four environmental isolates ofSalmonella, resistant to several drugs, were examined for plasmid carriage with four different plasmid DNA isolation procedures. The method of Birnboim and Doly gave the best results. Three of the strains possessed a single plasmid with molecular weights of 60 (kanamycin resistant), 44.5 (kanamcin resistant), and 23.4 Md (ampicillin and amoxicillin resistant); the other strain (resistant to tetracycline) harbored two plasmids of 69.8 and 2.2 Md. The 69.8 Md was the one responsible for resistance. All plasmids were fi−, and the 44.5 Md Kcr plasmid synthesized a sex pilus type F. Some properties related to the dissemination of R-plasmids, such as host range, tran…
Metabolic Networks of Sodalis glossinidius: A Systems Biology Approach to Reductive Evolution
2012
BackgroundGenome reduction is a common evolutionary process affecting bacterial lineages that establish symbiotic or pathogenic associations with eukaryotic hosts. Such associations yield highly reduced genomes with greatly streamlined metabolic abilities shaped by the type of ecological association with the host. Sodalis glossinidius, the secondary endosymbiont of tsetse flies, represents one of the few complete genomes available of a bacterium at the initial stages of this process. In the present study, genome reduction is studied from a systems biology perspective through the reconstruction and functional analysis of genome-scale metabolic networks of S. glossinidius.ResultsThe functiona…
Comparison of necrotoxigenic Escherichia coli isolates from farm animals and from humans.
1999
Abstract Necrotoxigenic Escherichia coli (NTEC) isolated from animals and humans can belong to the same serogroups/types and produce or carry the genes coding for fimbrial and afimbrial adhesins of the same family, P, S, F17, and/or AFA, raising the question of a potential zoonotic source of human infection. The main purpose of this study was to compare 239 NTEC1 strains (45 from cattle, 65 from humans and 129 from piglets) and 98 NTEC2 strains from cattle, using a uniform and standardized typing scheme. The O serogroups and the biotypes recognized amongst NTEC1 and NTEC2 strains were quite varied, although some were more frequently observed (serogroups O2, O4, O6, O8, O18, O78, and O83 and…
Two Host Clades, Two Bacterial Arsenals: Evolution through Gene Losses in Facultative Endosymbionts.
2015
International audience; Bacterial endosymbiosis is an important evolutionary process in insects, which can harbor both obligate and facultative symbionts. The evolution of these symbionts is driven by evolutionary convergence, and they exhibit among the tiniest genomes in prokaryotes. The large host spectrum of facultative symbionts and the high diversity of strategies they use to infect new hosts probably impact the evolution of their genome and explain why they undergo less severe genomic erosion than obligate symbionts. Candidatus Hamiltonella defensa is suitable for the investigation of the genomic evolution of facultative symbionts because the bacteria are engaged in specific relations…
Detection of oxidative mutagenesis by isoniazid and other hydrazine derivatives in Escherichia coli WP2 tester strain IC203, deficient in OxyR: stron…
1998
Abstract Strain IC203, deficient in the OxyR function, was sensitive to both cytotoxic and mutagenic effects of isoniazid (INH) whereas its parent, WP2 uvrA /pKM101, was resistant to these effects. Four other hydrazine compounds, hydrazine hydrate (HZH), phenylhydrazine (PHZ), hydralazine (HLZ) and nialamide (NLD), were mutagenic in WP2 uvrA /pKM101. Increases in mutagenicity were observed in IC203 for HZH and PHZ but not for HLZ and NLD. Growth inhibition zones by HZH, PHZ and NLD were larger in IC203 than in WP2 uvrA /pKM101. The enhancements in the effects of INH, HZH and PHZ in IC203 with respect to its oxyR + parent are considered to be caused by the production of reactive oxygen speci…
Detection of antibiotic-resistant bacteria and their resistance genes in wastewater, surface water, and drinking water biofilms.
2009
Abstract In view of the increasing interest in the possible role played by hospital and municipal wastewater systems in the selection of antibiotic-resistant bacteria, biofilms were investigated using enterococci, staphylococci, Enterobacteriaceae, and heterotrophic bacteria as indicator organisms. In addition to wastewater, biofilms were also investigated in drinking water from river bank filtrate to estimate the occurrence of resistant bacteria and their resistance genes, thus indicating possible transfer from wastewater and surface water to the drinking water distribution network. Vancomycin-resistant enterococci were characterized by antibiograms, and the vanA resistance gene was detect…