72 research outputs found
Molecular characterization of Escherichia coli strains that cause symptomatic and asymptomatic urinary tract infections
The differences between Escherichia coli strains associated with symptomatic and asymptomatic urinary tract infections (UTIs)remain to be properly determined. Here we examined the prevalence of plasmid types and bacteriocins, as well as genetic relatedness, in a defined collection of E. coli strains that cause UTIs. Comparative analysis identified a subgroup of strains with a high number of virulence genes (VGs) and microcins M/H47. We also identified associations between microcin genes, VGs, and specific plasmid types
Microcin H47 System: An Escherichia coli Small Genomic Island with Novel Features
Genomic islands are DNA regions containing variable genetic information related to secondary metabolism. Frequently, they have the ability to excise from and integrate into replicons through site-specific recombination. Thus, they are usually flanked by short direct repeats that act as attachment sites, and contain genes for an integrase and an excisionase which carry out the genetic exchange. These mobility events would be at the basis of the horizontal transfer of genomic islands among bacteria
Shark fossil diversity (Squalomorphii, Squatinomorphii, and Galeomorphii) from the Langhian of Brielas (Lower Tagus Basin, Portugal)
The fossiliferous marine Miocene sediments of the Lower Tagus Basin (Portugal) present
a great diversity of Chondrichthyes forms. The current study focuses on the fossil
sharks from the Langhian Vc unit of the Brielas section, located in the Setúbal
Peninsula. A total of 384 isolated fossil teeth were analysed and ascribed to 17 species from the Orders Hexanchiformes, Squaliformes, Squatiniformes, Lamniformes,
and Carcharhiniformes. Centrophorus granulosus and Iago angustidens are described
for the first time in Portuguese sediments, whereas Pachyscyllium dachiardii and
Rhizoprionodon ficheuri represent only their second reported occurrence. Galeorhinus
goncalvesi was already known from the Portuguese uppermost Miocene (Alvalade
Basin), but it is now recognized in older sediments. Furthermore, the new material
seems to include the first reported occurrence of Hexanchus cf. agassizi in Miocene
sediments. As a whole, these new findings support the previous palaeoenvironment
characterization of a warm infralittoral setting gradually deepening to a circalittoral
one, where seasonal upwelling phenomena could have occurred
A Novel Protein Kinase-Like Domain in a Selenoprotein, Widespread in the Tree of Life
Selenoproteins serve important functions in many organisms, usually providing essential oxidoreductase enzymatic activity, often for defense against toxic xenobiotic substances. Most eukaryotic genomes possess a small number of these proteins, usually not more than 20. Selenoproteins belong to various structural classes, often related to oxidoreductase function, yet a few of them are completely uncharacterised
Une plante vénéneuse saharienne : Caralluma venenosa
Gast M., Poey J. Une plante vénéneuse saharienne : Caralluma venenosa. In: Journal d'agriculture tropicale et de botanique appliquée, vol. 15, n°12, décembre 1968. pp. 546-548
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