No abstract

The presence of ochratoxin A (OTA), fumonisin B2 (FB2) and black aspergilli in raisins from Western Greece regions (Messinia, Corinthia, Achaia, Ilia and Zante Island) was investigated in relation to the different geographic and climatic conditions in the 2011 growing season. The biseriate species Aspergillus niger "aggregate" and A. carbonarius were mainly identified. The population of A. niger "aggregate" species occurred in all raisin samples at colony-forming units (CFU) concentrations significantly higher (mean 2.2 × 10(5) CFU g(-1) homogenate) than those of A. carbonarius population (mean 4.9 × 10(3) CFU g(-1) homogenate), which occurred in 80% of the raisin samples. OTA was found in 73% of the samples at levels ranging from 0.1 µg kg(-1) to 98.2 µg kg(-1), with the highest level occurring in a raisin sample from Ilia that also contained the highest level of A. carbonarius. The European Union legal limit for OTA was exceeded in 15% of the raisin samples. FB2 was found in 29% of the raisin samples at levels ranging from 7.1 µg kg(-1) to 25.5 µg kg(-1), with 20% of the samples co-occurring with OTA. Principal-component analysis was applied to levels of mycotoxins, fungal contamination, geographical data and environmental conditions recorded in the harvesting (August) or drying (September) period. Principal-component analysis clearly indicated a good direct correlation of rainfall and relative humidity with OTA and A. carbonarius contamination. A lack of clustering was observed when A. niger and FB2 contamination were considered. This is the first report on the co-occurrence of the mycotoxins OTA and FB2 in dried vine fruits from Greece.

The fabrication of electrospun magnetoactive fibrous nanocomposite membranes based on the water-soluble and biocompatible poly(ethylene oxide) (PEO), the biocompatible and biodegradable poly(L-lactide) (PLLA) and preformed oleic acid-coated magnetite nanoparticles (OA.Fe3O4) is reported. Visualization of the membranes by electron microscopy techniques reveals the presence of continuous fibers of approximately 2 μm in diameter, with the magnetic nanoparticles being evenly distributed within the fibers, retaining at the same time their nanosized diameters (≈ 5 nm). Thermal gravimetric analysis measurements suggest that the magnetic nanoparticles embedded within the polymer fibers affect favorably the thermal stability of the membranes. Moreover, assessment of their magnetic characteristics by vibrating sample magnetometry discloses tunable superparamagnetic behavior at ambient temperature. For the first time, the biocompatibility and biodegradability of PEO/PLLA and the tunable magnetic activity of the OA.Fe3O4 are combined in the same drug delivery system, with N-acetyl-p-aminophenol (acetaminophen) as a proof-of-concept pharmaceutical. Furthermore, their heating ability under alternating current (AC) magnetic field conditions is evaluated using frequency of 110 kHz and corresponding magnetic field strength of 25 mT (19.9 kA/m). Consequently, these magnetoactive fibrous nanocomposites exhibit promising characteristics for future exploitation in magnetothermally triggered drug delivery.

Complement-mediated opsonization, phagocytosis, and immune stimulation are critical processes in host defense and homeostasis, with the complement activation fragment iC3b playing a key effector role. To date, however, there is no high-resolution structure of iC3b, and some aspects of its structure-activity profile remain controversial. Here, we employed hydrogen-deuterium exchange mass spectrometry (HX-MS) to describe the structure and dynamics of iC3b at a peptide resolution level in direct comparison with its parent protein C3b. In our HX-MS study, 264 peptides were analyzed for their deuterium content, providing almost complete sequence coverage for this 175-kDa protein. Several peptides in iC3b showed significantly higher deuterium uptake when compared to C3b, revealing more dynamic, solvent-exposed regions. Most of them resided in the CUB domain, which contains the heptadecapeptide C3f that is liberated during the conversion of C3b to iC3b. Our data suggest a highly disordered CUB, which has acquired a state similar to that of intrinsically disordered proteins, resulting in a predominant form of iC3b that features high structural flexibility. The structure was further validated using an anti-iC3b monoclonal antibody that was shown to target an epitope in the CUB region. The information obtained in this work allows us to elucidate determinants of iC3b specificity and activity and provide functional insights into the protein’s recognition pattern with respect to regulators and receptors of the complement system.