Morphological analysis of the sheathed flagellum of Brucella melitensis

<p>Abstract</p> <p>Background</p> <p>It was recently shown that <it>B. melitensis </it>is flagellated. However, the flagellar structure remains poorly described.</p> <p>Findings</p> <p>We analyzed the structure of the polar sheathed flagellum of <it>B. melitensis </it>by TEM analysis and demonstrated that the Ryu staining is a good method to quickly visualize the flagellum by optical microscopy. The TEM analysis demonstrated that an extension of the outer membrane surrounds a filament ending by a club-like structure. The Δ<it>ftcR</it>, Δ<it>fliF</it>, Δ<it>flgE </it>and Δ<it>fliC </it>flagellar mutants still produce an empty sheath.</p> <p>Conclusions</p> <p>Our results demonstrate that the flagellum of <it>B. melitensis </it>has the characteristics of the sheathed flagella. Our results also suggest that the flagellar sheath production is not directly linked to the flagellar structure assembly and is not regulated by the FtcR master regulator.</p

Acute respiratory viral infections aggravate arterial endothelial dysfunction in children with type 1 diabetes mellitus.

Despite improvements in therapy for children with type 1 diabetes, the prevalence of cardiovascular morbidity in adulthood due to accelerated atherosclerosis remains significant (1). Similar to other cardiovascular risk factors, the diabetic state facilitates arterial endothelial injury, a primary event in the pathogenesis of atherosclerosis (2). Although several pediatric studies have reported an association of diabetes with arterial endothelial dysfunction (3,4), pathogenic animal studies have suggested that even though this disease predisposes to endothelial dysfunction and atherosclerosis, it might not be sufficient to cause them (5). Notably, type 1 diabetes increases the propensity for both chronic and acute infections in part by weakening the immune mechanisms (6). The risk is particularly increased for respiratory tract infections, but other infections have also been associated with diabetes (7). Furthermore, diabetic patients are at greater risk for infection-related mortality (8), and the excess risk appears to be linked to cardiovascular diseases (9). In the present study, we investigated whether viral respiratory tract infections in children with type 1 diabetes might impose an additional burden on the arterial endothelial function