Interplay between extracellular matrix components of Pseudomonas putida biofilms

The extracellular matrix of bacterial biofilms has at least two key functions: to serve as a structural scaffold for the multicellular community, and to play a protective role against external stress. In this work, we report a compensatory effect whereby Pseudomonas putida reacts to the lack of either of the two main surface proteins involved in biofilm formation, LapA and LapF, by increasing expression and production of a species-specific EPS. Elevated levels of the second messenger molecule cyclic di-GMP alter the balance of extracellular matrix components, and the phenotypes of lapA and lapF mutants under these conditions are indicative of direct interactions taking place between large secreted proteins and exopolysaccharides. Our data suggest the existence of a mechanism by which bacteria would sense alterations in the composition of the extracellular matrix, leading to changes in expression of the different elements.     

Evaluation of the genotoxic potential of dimethyl sulfoxide (DMSO) in meristematic cells of the root of Vicia faba

Dimethyl sulfoxide (DMSO) is an organic solvent with several biological applications. It is extensively used to dissolve compounds that hardly dissolve in water to detect their genotoxic activity in vitro. In this study DMSO will be tested to determine its genotoxic potential. The effect of DMSO on the frequency of chromosomal aberrations in anaphase as well as DNA fragmentation through the comet assay has been evaluated in the meristematic cells of the root tips of Vicia faba. It has been observed that the frequency of chromosomal aberrations increases when the concentration of DMSO increases, reaching its maximum value with 20% of DMSO and decreasing at 30 and 40% of DMSO, in comparison to this maximum value, but significantly higher than the values observed in the control. Similarly, the percentage of fragmentation and damage index evaluated through the comet assay showed the same behavior; some of the possible mechanisms of action are discussed.     

Influence of Fermentation and Drying Materials on the Contamination of Cocoa Beans by Ochratoxin A

Ochratoxin A (OTA) is a mycotoxin produced mainly by species of Aspergillus and Penicillium. Contamination of food with OTA is a major consumer health hazard. In Côte d’Ivoire, preventing OTA contamination has been the subject of extensive study. The current study was conducted to evaluate the influence of fermentation and drying materials on the OTA content in cocoa. For each test, 7000 intact cocoa pods were collected, split open to remove the beans, fermented using 1 of 3 different materials, sun-dried on 1 of 3 different platform types and stored for 30 days. A total of 22 samples were collected at each stage of post-harvesting operations. The OTA content in the extracted samples was then quantified by high-performance liquid chromatography. OTA was detected in beans at all stages of post-harvesting operations at varying levels: pod-opening (0.025 ± 0.02 mg/kg), fermentation (0.275 ± 0.2 mg/kg), drying (0.569 ± 0.015 mg/kg), and storage (0.558 ± 0.04 mg/kg). No significant relationships between the detected OTA level and the materials used in the fermentation and drying of cocoa were observed.     

Antiphospholipid syndrome: From pathogenesis to novel immunomodulatory therapies

Antiphospholipid syndrome (APS) is characterized by recurrent thrombosis and pregnancy morbidity in association with the persistent presence of circulating antiphospholipid antibodies (aPL). APS remains the most frequent cause of acquired hypercoagulability and recurrent miscarriage. Long-term anticoagulation therapy is the only treatment with proven benefit in the APS. Anticoagulation is not effective in all patients and carries a risk of bleeding. Recent improvements in the understanding of the pathogenic mechanisms have led to the identification of potential targets and future therapies for APS. In contrast to non-specific anticoagulation, the emergence of immunomodulatory drugs provides the possibility of interfering with specific pathogenic pathways. Novel therapies might be used in the future for APS.     

Pediatric Cutaneous Lupus Erythematosus Treated with Pulsed Dye Laser

Pulsed dye laser (PDL) has been used in adults to treat refractory cutaneous lupus erythematosus (CLE). We report the first case of CLE in a child successfully treated with PDL.     

DOSE RESPONSE EFFECT OF Paracoccidioides brasiliensis IN AN EXPERIMENTAL MODEL OF ARTHRITIS

Paracoccidioidomycosis (PCM) is caused by the dimorphic fungus Paracoccidioides brasiliensis (Pb) and corresponds to prevalent systemic mycosis in Latin America. The aim of the present work was to evaluate the dose response effect of the fungal yeast phase for the standardization of an experimental model of septic arthritis. The experiments were performed with groups of 14 rats that received doses of 10³, 10⁴ or 10⁵ P. brasiliensis (Pb18) cells. The fungi were injected in 50 µL of phosphate-buffered saline (PBS) directly into the knee joints of the animals. The following parameters were analyzed in this work: the formation of swelling in knees infused with yeast cells and the radiological and anatomopathological alterations, besides antibody titer by ELISA. After 15 days of infection, signs of inflammation were evident. At 45 days, some features of damage and necrosis were observed in the articular cartilage. The systemic dissemination of the fungus was observed in 11% of the inoculated animals, and it was concluded that the experimental model is able to mimic articular PCM in humans and that the dose of 10⁵ yeast cells can be used as standard in this model.