Lichen butyrolactone derivatives disrupt oral bacterial membrane.

We have previously demonstrated that out of the butyrolactones series synthesized based on the natural lichen metabolite lichesterinic acid, compound (B-13) was the most effective against oral bacteria. However, its antibacterial mechanism is still unknown. In this study, we have investigated its bacterial localization by synthesizing a fluorescently labeled B-13 with NBD while maintaining its antibacterial activity. We showed that this compound binds to Streptococcus gordonii cell surface, as demonstrated by HPLC analysis. By adhering to cell surface, B-13 induced cell wall disruption leading to the release of bacterial constituents and consequently, the death of S. gordonii, a Gram-positive bacterium. A Gram-negative counterpart, Porphyromanas gingivalis, showed also cracked and ruptured cells in the presence of B-13. Besides, we also demonstrated that the analog of B-13, B-12, has also induced disruption of P. gingivalis and S. gordonii. This study revealed that butyrolactones can be considered as potent antibacterial compounds against oral pathogens causing medical complications.

Roseburia spp.: a marker of health?

The genus Roseburia consists of obligate Gram-positive anaerobic bacteria that are slightly curved, rod-shaped and motile by means of multiple subterminal flagella. It includes five species: Roseburia intestinalis, R. hominis, R. inulinivorans, R. faecis and R. cecicola. Gut Roseburia spp. metabolize dietary components that stimulate their proliferation and metabolic activities. They are part of commensal bacteria producing short-chain fatty acids, especially butyrate, affecting colonic motility, immunity maintenance and anti-inflammatory properties. Modification in Roseburia spp. representation may affect various metabolic pathways and is associated with several diseases (including irritable bowel syndrome, obesity, Type 2 diabetes, nervous system conditions and allergies). Roseburia spp. could also serve as biomarkers for symptomatic pathologies (e.g., gallstone formation) or as probiotics for restoration of beneficial flora.

[Association multiple exostoses and ankylosing spondylitis: about one case and a review of the literature]. / Association maladie exostosante et spondylarthrite ankylosante: a propos d'un cas et une revue de la litterature.

We report the case of a 25-years-old man who had an ankylosing spondylitis associated with multiple exostoses. The patient had hip pain of inflammatory origin and back stiffness with x-ray findings suggestive of bilaterral sacroilitis, coxitis as well as exostosis of the humerus, radius, femor and tibia. This is occurred in Turkey, the association was described as a simple concidence due to the difference in the genetic mechanisms involved. A more detailed genetic study of these two entities well be helpful for a better understanding of this association.