Exocytic transmitter release is regulated by the SNARE complex, which contains a vesicular protein, synaptobrevin2 (Sb2). However, Sb2 vesicular arrangement is unclear. Here we use super-resolution fluorescence microscopy to study the prevalence and distribution of endogenous and exogenous Sb2 in single vesicles of astrocytes, the most abundant glial cells in the brain. We tag Sb2 protein at C- and N termini with a pair of fluorophores, which allows us to determine the Sb2 length and geometry. To estimate total number of Sb2 proteins per vesicle and the quantity necessary for the formation of fusion pores, we treat cells with ATP to stimulate Ca2+-dependent exocytosis, increase intracellular alkalinity to enhance the fluorescence presentation of yellow-shifted pHluorin (YpH), appended to the vesicle lumen domain of Sb2, and perform photobleaching of YpH fluorophores. Fluorescence intensity analysis reveals that the total number of endogenous Sb2 units or molecules per vesicle is (-25.
COBISS.SI-ID: 31384793
This communication reports the first experimental evidence that in the bladder cancer model, membranous components labelled with the DiO dye and the cholera toxin subunit B can be transported from highly malignant (T24) to non-malignant (RT4) cells by extracellular vesicles. Taking into account the presence of stable membranous nanostructures found by scanning electron microscopy, we suggest a possible uptake mechanism in recipient cells through fusion with highly curved membranous regions.
COBISS.SI-ID: 10148948
Water-soluble, biodegradable, and biocompatible poly(ester-amide) dendrimers with hydroxyl functional groups are synthesized from previously prepared AB2 adduct of 2,2-bis(hydroxymethyl) propanoic acid (bis-MPA) and glycine as a repeating unit. Two esterification procedures using different coupling reagent/catalyst systems (DCC/DPTS or EDC/DMAP) are studied with respect to efficiency, ease of products purification, and quality of the final products. Both procedures have their own benefits and drawbacks, depending on dendrimer generation. The synthesized poly(ester-amide) dendrimers as well as commercially available bis-MPA dendrimers, poly(ester-amide) hyperbranched polymer, and poly(vinyl alcohol) are used for preparation of solid dispersions of sulfonylurea antidiabetic drug glimepiride to improve its poor water-solubility. In vitro dissolution studies show in comparison with pure glimepiride in crystalline or amorphous form, to the same extent improved glimepiride solubility for solid dispersions based on dendritic polymers, but not for poly(vinyl alcohol). The amount of glimepiride complexed with both dendrimer types increases with dendrimer generation.
COBISS.SI-ID: 5548826