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Abstract The Gram-positive anaerobic bacterium Cutibacterium acne s is a commensal of the human skin, but also an opportunistic pathogen that contributes to the pathophysiology of the skin disease acne vulgaris. Moreover, C. acnes , in addition to other skin-colonizing bacteria such as S. epidermidis and S. aureus , is an emerging pathogen of implant-associated infections. Notably, C. acnes isolates exhibit marked heterogeneity and can be divided into at least 6 phylotypes by multilocus sequence typing. It is becoming increasingly evident that biofilm formation is a relevant factor for C. acnes virulence, but information on biofilm formation by diverse C. acnes isolates is limited. In this study we performed a first comparative analysis of 58 diverse skin- or implant-isolates covering all six C. acnes phylotypes to investigate biofilm formation dynamics, biofilm morphology and attachment properties to abiotic surfaces. The results presented herein suggest that biofilm formation correlates with the phylotype, rather than the anatomical isolation site. IA1 isolates, particularly SLST sub-types A1 and A2, showed highest biofilm amounts in the microtiter plate assays, followed by isolates of the IC, IA2 and II phylotypes. Microscopic evaluation revealed well-structured three-dimensional biofilms and relatively high adhesive properties to abiotic surfaces for phylotypes IA1, IA2 and IC. Representatives of phylotype III formed biofilms with comparable biomass, but with less defined structures, whereas IB as well as II isolates showed the least complex three-dimensional morphology. Proteinase K- and DNase I-treatment reduced attachment rates of all phylotypes, therefore, indicating that extracellular DNA and proteins are critical for adhesion to abiotic surfaces. Moreover, proteins seem to be pivotal structural biofilm components as mature biofilms of all phylotypes were proteinase K-sensitive, whereas the sensitivity to DNase I-treatment varied depending on the phylotype. [ABSTRACT FROM AUTHOR]

The facultative human pathogen Vibrio cholerae has to adapt to different environmental conditions along its lifecycle by means of transcriptional, translational and post-translational regulation. This study provides a first comprehensive analysis regarding the contribution of the cytoplasmic AAA+ proteases Lon, ClpP and HslV to distinct features of V. cholerae behaviour, including biofilm formation, motility, cholera toxin expression and colonization fitness in the mouse model. While absence of HslV did not yield to any altered phenotype compared to wildtype, absence of Lon or ClpP resulted in significantly reduced colonization in vivo. In addition, a Δ lon deletion mutant showed altered biofilm formation and increased motility, which could be correlated with higher expression of V. cholerae flagella gene class IV. Concordantly, we could show by immunoblot analysis, that Lon is the main protease responsible for proteolytic control of FliA, which is required for class IV flagella gene transcription, but also downregulates virulence gene expression. FliA becomes highly sensitive to proteolytic degradation in absence of its anti-sigma factor FlgM, a scenario reported to occur during mucosal penetration due to FlgM secretion through the broken flagellum. Our results confirm that the high stability of FliA in the absence of Lon results in less cholera toxin and toxin corgulated pilus production under virulence gene inducing conditions and in the presence of a damaged flagellum. Thus, the data presented herein provide a molecular explanation on how V. cholerae can achieve full expression of virulence genes during early stages of colonization, despite FliA getting liberated from the anti-sigma factor FlgM. [ABSTRACT FROM AUTHOR]

Abstract: The intermolecular interactions and miscibility behavior between poly(ether imide) (Ultem®1000) and a copolyester of bisphenol-A with a mixture of terephthalic and isophthalic acid (Ardel®D-100) in compositions of 100/0, 80/20, 60/40, 40/60, 20/80 and 0/100 have been investigated in dilute solutions in chloroform. An Ubbelohde-type home-made viscometer was used to determine the specific viscosities of the blends in a constant temperature bath. Several viscosity interaction parameters used as the criteria of miscibility were determined from viscosity measurements. The parameters suggested that Ultem®1000 and Ardel®D-100 were miscible. The miscibility of the polymers was confirmed by the results of differential scanning calorimetry measurements. [Copyright &y& Elsevier]

In this study, the performance of the montmorillonite-filled sodium alginate/gelatin (SA-GEL-MMT) ternary biocomposite microbeads on the adsorptive removal of crystal violet (CV) dye was investigated. Firstly, the composites containing different weight ratios of MMT such as 10 %, 15 %, and 20 % were prepared. The composite beads were cross-linked using a calcium chloride (3%wt/v) solution. To determine the optimum sorption conditions the studies were performed at different parameters namely temperature, pH, contact time, sorbent dose, and dye concentration. From the sorption studies, the maximum capacity of the microbeads was found as 1000.0 mg/g whereas the maximum removal of the dye was 92.1 % at pH = 7 and a temperature of 25 °C. Additionally, the kinetic studies showed that the sorption of the dye followed the pseudo-second-order kinetics. Moreover, the adsorptive removal of the dye occurs spontaneously. This study suggests that the use of SA-GEL-MMT can be highly effective and reusable for the treatment of wastewater. [Display omitted] • Langmuir isotherm was found to be the most suitable model for CV dye. • The q m values reached up to 1000.0 mg/g at 25 °C for SA-GEL-MM-20. • The composites were found to be extremely effective and reusable adsorbent. • Composite microbeads remain effective after the 5th cycle. [ABSTRACT FROM AUTHOR]

Recently, the negative effects of organic/inorganic pollutants such as dyes and heavy metals on the environment, increasing in direct proportion with increasing industrial developments and urbanization, have become an important problem. Lignocellulosic materials have emerged as promising materials for the treatment of wastewater which is containing pollutants due to their low cost, sustainability, abundance, environmentally friendly nature, and high efficiency. In this study, Lolium perenne seeds were utilized for the adsorptive removal of Safranine T from an aqueous environment for the first time. From the adsorption results, it was determined that the adsorption process was suitable for the Langmuir isotherm (r 2 = 0.99). As a result of the adsorption processes, it was observed that the removal of the Safranine T dye reached up to 91.37%, and the adsorption capacity was calculated as 322.58 mg/g at 25 °C and pH ≅ 7 according to the Langmuir model. From the kinetic models, it was determined that the adsorption process followed the pseudo-second-order kinetic model. Furthermore, the surface area of adsorbent seeds was calculated as 142.32 m2/g using the Langmuir model. Thermodynamic experiments also stated that the process occurred exothermically ( Δ H A o = − 6.38 k J / m o l at 25 °C) and spontaneously ( Δ G A o = − 27.57 k J / m o l at 25 °C) in nature. The adsorption mechanism was attributed to the electrostatic interactions, π-π, n-π interactions, and H-bonds between the functional groups of the surface of the adsorbent and dye molecules. This study suggests that Lolium perenne seeds are promising and reusable adsorbents for the treatment of wastewater. [Display omitted] • The adsorption capacity of Lolium perenne seeds reached up to 322.58 mg/g at 25 °C. • The removal percentage of Safranin T reached up to 91.37%. • The surface area of adsorbent seeds was calculated as 142.32 m2/g.. • Lolium perenne seeds remained efficient after 5 cycles.. [ABSTRACT FROM AUTHOR]

Knowing the surface properties of ceramic materials is important to determine the area of use. The carbide-based ceramics namely boron carbide and silicon carbide were synthesized and characterized. The surface properties of boron carbide and silicon carbide ceramic materials were examined by the inverse gas chromatography method. Experiments of inverse gas chromatography were carried out to determine the specific adsorption free energy and the specific adsorption enthalpy corresponding to the acid-base properties of both materials. The inverse gas chromatography measurements exhibited values of acidity constants of 0.137 and 0.086 and basic constants of 0.104 and 0.077 for boron carbide and silicon carbide, respectively. The values obtained for and parameters indicated that boron carbide and silicon carbide have an acidic character. [Display omitted] • Surface characterization of B4C and SiC were determined by IGC-ID technique. • Polar and non-polar probes were used to examine the surface properties. • γ S D values were calculated using the Schultz and Dorris-Gray methods. • The surface of B4C and SiC was determined as acidic. • B4C and SiC were characterized by FTIR-ATR and XRD analyses. [ABSTRACT FROM AUTHOR]