Multilocus Phylogenetic Study of the Scheffersomyces Yeast Clade and Characterization of the N-Terminal Region of Xylose Reductase Gene

Many of the known xylose-fermenting (X-F) yeasts are placed in the Scheffersomyces clade, a group of ascomycete yeasts that have been isolated from plant tissues and in association with lignicolous insects. We formally recognize fourteen species in this clade based on a maximum likelihood (ML) phylogenetic analysis using a multilocus dataset. This clade is divided into three subclades, each of which exhibits the biochemical ability to ferment cellobiose or xylose. New combinations are made for seven species of Candida in the clade, and three X-F taxa associated with rotted hardwood are described: Scheffersomyces illinoinensis (type strain NRRL Y-48827T  =  CBS 12624), Scheffersomyces quercinus (type strain NRRL Y-48825T  =  CBS 12625), and Scheffersomyces virginianus (type strain NRRL Y-48822T  =  CBS 12626). The new X-F species are distinctive based on their position in the multilocus phylogenetic analysis and biochemical and morphological characters. The molecular characterization of xylose reductase (XR) indicates that the regions surrounding the conserved domain contain mutations that may enhance the performance of the enzyme in X-F yeasts. The phylogenetic reconstruction using XYL1 or RPB1 was identical to the multilocus analysis, and these loci have potential for rapid identification of cryptic species in this clade

Triclosan resistance reversion by encapsulation in chitosan-coated-nanocapsule containing α-bisabolol as core: development of wound dressing

João Guilherme B De Marchi,1 Denise S Jornada,1 Fernanda K Silva,1 Ana L Freitas,2 Alexandre M Fuentefria,2 Adriana R Pohlmann,1,2 Silvia S Guterres1 1Pharmaceutical Sciences Graduate Program, 2Department of Organic Chemistry, Institute of Chemistry, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil Abstract: The use of nanoparticles may be particularly advantageous in treating bacterial infections due to their multiple simultaneous mechanisms of action. Nanoencapsulation is particularly useful for lipophilic drugs. In this scenario, triclosan is considered a good candidate due to its lipophilicity, broad-spectrum activity, and safety. In the present study, we have developed and characterized an antimicrobial suspension of triclosan and α-bisabolol against pathogenic strains that are resistant (Pseudomonas aeruginosa) and susceptible (Escherichia coli, Staphylococcus aureus, and Candida albicans) to triclosan. We also aimed to determine the minimum inhibitory concentration, using serial microdilution adapted from a CLSI methodology (Clinical and Laboratory Standards Institute). Challenge test was used to confirm the antimicrobial effectiveness of the nanocapsule formulation, as well as after its incorporation into a commercial wound dressing (Veloderm®). The zeta potential of P. aeruginosa before and after contact with cationic nanocapsules and the ratio between the number of nanocapsules per colony forming unit (CFU) were determined to evaluate a possible interaction between nanocapsules and bacteria. The results showed that nanoencapsulation has improved the antimicrobial activity when tested with two different methodologies. The number of nanocapsules per CFU was high even in great dilutions and the zeta potential was reverted after being in contact with the cationic nanocapsules. The nanocapsules were able to improve the activity of triclosan, even when tested within 28 days and when dried in the wound dressing. Keywords: antimicrobial effect, triclosan, α-bisabolol, chitosan, nanocapsule

CRITICAL ISSUES IN MANUFACTURING DENTAL BRACKETS BY POWDER INJECTION MOLDING

An early success of powder injection molding (PIM) for medical applications was orthodontic brackets, with annual global sales estimated to be similar to$130 million. However, utilizing PIM in the manufacture of medical products poses several challenges. Apart from stringent quality requirements and design issues in this high-volume manufacturing process, attention must also be focused on understanding the effect of exposure of the material to the biological environment. The current study details three cross-functional research efforts focused on challenges in the PIM of biomedical parts, using dental brackets as an example. The first study addresses dimensional scatter of microscale features in alumina dental brackets. The second study examines imbalance filling in multi-cavity tooling. The third study covers the characterization of biofilm formation on dental brackets. Collectively, the three studies demonstrate the importance of multidisciplinary efforts to continue to increase opportunities in the manufacturing of metal and ceramic medical components by PIM.X115sciescopu