Tratamiento quirúrgico de ptosis palpebral miogénica adquirida

Objective: To report the surgical outcome of aponeurosis surgery in patients with acquired myogenic eyelid ptosis and describe surgical guidelines for their correction. Methods: The clinical records of two patients with acquired myogenic eyelid ptosis after surgical correction were reviewed. Results: In two patients with acquired myogenic eyelid ptosis and barely good levator function, levator resection surgery was performed. Corneal complications appeared in both cases. Conclusion: Patients with acquired myogenic eyelid ptosis are at risk of post-operative surgical complications from corneal exposure. Surgical correction should be conservative and performed only when the visual axis is compromise

Arbuscular Mycorrhizal Fungi and their Value for Ecosystem Management

Arbuscular Mycorrhizal Fungi (AMF) are root obligate symbionts of nearly all the plants living on Earth. They are considered as living fossils: there are evidences that date back to 460 million years ago their presence on our planet. Taxonomically, they belong to the Glomeromycota phylum. They are found in roots of 80% of plant species and give and get back benefits to their partners, as happens in all mutual symbiotic relationships. They build up a bridge between plant and soil, growing their mycelia both inside and outside plant roots. AMF provide the plant with water, soil mineral nutrients (mainly phosphorus and nitrogen), and pathogen protection. In exchange, photosynthetic compounds are transferred to the fungus. Besides physiological benefits to the host-plant, AMF play an important ecological role. They are important in soil structuring thanks to their thick extraradical hyphal network able to aggregate soil particles. They help plants establish in degraded ecosystems (e.g. desert areas and mine spoils) and positively affect phytoremediation. They can influence processes (i.e. soil carbon sequestration) related to climate change. Last but not least, their belowground presence and diversity can positively affect the aboveground plant biodiversity and productivity. These roles played by AMF for the ecosystem functioning lead to consider them as key soil organisms. Therefore, every AMF aspect is extensively studied: from biological features, through biogeography and biodiversity, to phylogeny. [...]JRC.H.5-Land Resources Managemen

Bridging reproductive and microbial ecology: a case study in arbuscular mycorrhizal fungi

Offspring size is a key trait for understanding the reproductive ecology of species, yet studies addressing the ecological meaning of offspring size have so far been limited to macro-organisms. We consider this a missed opportunity in microbial ecology and provide what we believe is the first formal study of offspring-size variation in microbes using reproductive models developed for macro-organisms. We mapped the entire distribution of fungal spore size in the arbuscular mycorrhizal (AM) fungi (subphylum Glomeromycotina) and tested allometric expectations of this trait to offspring (spore) output and body size. Our results reveal a potential paradox in the reproductive ecology of AM fungi: while large spore-size variation is maintained through evolutionary time (independent of body size), increases in spore size trade off with spore output. That is, parental mycelia of large-spored species produce fewer spores and thus may have a fitness disadvantage compared to small-spored species. The persistence of the large-spore strategy, despite this apparent fitness disadvantage, suggests the existence of advantages to large-spored species that could manifest later in fungal life history. Thus, we consider that solving this paradox opens the door to fruitful future research establishing the relationship between offspring size and other AM life history traits

Salmonella Biofilm Formation on Aspergillus niger Involves Cellulose – Chitin Interactions

Salmonella cycles between host and nonhost environments, where it can become an active member of complex microbial communities. The role of fungi in the environmental adaptation of enteric pathogens remains relatively unexplored. We have discovered that S. enterica Typhimurium rapidly attaches to and forms biofilms on the hyphae of the common fungus, Aspergillus niger. Several Salmonella enterica serovars displayed a similar interaction, whereas other bacterial species were unable to bind to the fungus. Bacterial attachment to chitin, a major constituent of fungal cell walls, mirrored this specificity. Pre-incubation of S. Typhimurium with N-acetylglucosamine, the monomeric component of chitin, reduced binding to chitin beads by as much as 727-fold and inhibited attachment to A. niger hyphae considerably. A cellulose-deficient mutant of S. Typhimurium failed to attach to chitin beads and to the fungus. Complementation of this mutant with the cellulose operon restored binding to chitin beads to 79% of that of the parental strain and allowed for attachment and biofilm formation on A. niger, indicating that cellulose is involved in bacterial attachment to the fungus via the chitin component of its cell wall. In contrast to cellulose, S. Typhimurium curli fimbriae were not required for attachment and biofilm development on the hyphae but were critical for its stability. Our results suggest that cellulose–chitin interactions are required for the production of mixed Salmonella-A. niger biofilms, and support the hypothesis that encounters with chitinaceous alternate hosts may contribute to the ecological success of human pathogens

Antibiofilm Activity of an Exopolysaccharide from Marine Bacterium Vibrio sp. QY101

Bacterial exopolysaccharides have always been suggested to play crucial roles in the bacterial initial adhesion and the development of complex architecture in the later stages of bacterial biofilm formation. However, Escherichia coli group II capsular polysaccharide was characterized to exert broad-spectrum biofilm inhibition activity. In this study, we firstly reported that a bacterial exopolysaccharide (A101) not only inhibits biofilm formation of many bacteria but also disrupts established biofilm of some strains. A101 with an average molecular weight of up to 546 KDa, was isolated and purified from the culture supernatant of the marine bacterium Vibrio sp. QY101 by ethanol precipitation, iron-exchange chromatography and gel filtration chromatography. High performance liquid chromatography traces of the hydrolyzed polysaccharides showed that A101 is primarily consisted of galacturonic acid, glucuronic acid, rhamnose and glucosamine. A101 was demonstrated to inhibit biofilm formation by a wide range of Gram-negative and Gram-positive bacteria without antibacterial activity. Furthermore, A101 displayed a significant disruption on the established biofilm produced by Pseudomonas aeruginosa, but not by Staphylococcus aureus. Importantly, A101 increased the aminoglycosides antibiotics' capability of killing P. aeruginosa biofilm. Cell primary attachment to surfaces and intercellular aggregates assays suggested that A101 inhibited cell aggregates of both P. aeruginosa and S. aureus, while the cell-surface interactions inhibition only occurred in S. aureus, and the pre-formed cell aggregates dispersion induced by A101 only occurred in P. aeruginosa. Taken together, these data identify the antibiofilm activity of A101, which may make it potential in the design of new therapeutic strategies for bacterial biofilm-associated infections and limiting biofilm formation on medical indwelling devices. The found of A101 antibiofilm activity may also promote a new recognition about the functions of bacterial exopolysaccharides