RESUMO
Efficient tools are still being searched for to substitute the viral vectors in nucleic acid delivery applications. One of the most severe constraints in producing them is related to the strict reproducibility of their molecular characteristics, which is ensured through the synthesis. In this work, we report an original route to obtain polycationic nanoentities with low variability, which are able to act as cooperating carriers for dsDNA complexation and transport. The carriers are synthesized by rigorous conjugation of ß-cyclodextrin (ß-CD) with precise ratios of 2 kDa branched poly(ethyleneimine) (b-PEI) and 0.75 kDa poly(ethylene glycol) (PEG). Low cytotoxicity was the key parameter of the carrier design, besides the highest possible transfection ability, and both of these features were proven by HeLa cell culture assays. A reporter gene which induces the expression of green fluorescent protein (GFP), inserted in a plasmid, was used to perform the necessary quantitative measurements. In silico molecular modelling guided the carrier design and confirmed the functional mimicry of histones in the tight and compact nucleosome-like spiral packaging of dsDNA. The carrier molecules, synthesized with high reproducibility, are expected to be feasible for application in gene transfection.
RESUMO
This is the first multi-centre study regarding yeast infections in Romania. The aim was to determine the aetiological spectrum and susceptibility pattern to fluconazole, voriconazole and the novel compound MXP-4509. The 551 isolates were identified using routine laboratory methods, matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF MS) and DNA sequence analysis. Susceptibility testing was performed using the European Committee for Antimicrobial Susceptibility Testing (EUCAST) method and breakpoints. The yeasts originated from superficial infections (SUP, 51.5 %), bloodstream infections (BSI, 31.6 %) and deep-seated infections (DEEP, 16.9 %), from patients of all ages. Nine genera and 30 species were identified. The 20 Candida species accounted for 94.6 % of all isolates. C. albicans was the overall leading pathogen (50.5 %). Lodderomyces elongisporus is reported for the first time as a fungaemia cause in Europe. C. glabrata and Saccharomyces cerevisiae, as well as the non-Candida spp. and non-albicans Candida spp. groups, showed decreased fluconazole susceptibility (<75 %). The overall fluconazole resistance was 10.2 %. C. krusei accounted for 27 of the 56 fluconazole-resistant isolates. The overall voriconazole resistance was 2.5 % and was due mainly to C. glabrata and C. tropicalis isolates. Fluconazole resistance rates for the three categories of infection were similar to the overall value; voriconazole resistance rates differed: 4 % for BSI, 3.2 % for DEEP and 1.4 % for SUP. The antifungal activity of MXP-4509 was superior to voriconazole against C. glabrata and many fluconazole-resistant isolates. There was a large percentage of non-albicans Candida isolates. A large part of the high fluconazole resistance was not acquired but intrinsic, resulting from the high percentage of C. krusei.
