Neoglycoconjugates of mannan with bovine serum albumin and their interaction with lectin concanavalin A

Neoglycoconjugates were prepared from mannan isolated from yeast Saccharomyces cerevisiae and activated by periodate oxidation to create aldehyde groups. Various degrees of oxidation introduced 11-28 aldehyde groups per mannan molecule and simultaneously resulted in a molar mass decrease from 46 to 44.5-31 kDa. The activated mannans were subsequently conjugated with bovine serum albumin forming neoglycoconjugates. Some parameters of these mannan-bovine serum albumin conjugates were characterized: saccharide content 25-30% w/w, molar mass within the range 169-246 kDa, and polydispersion (M-w/M-n) from 2.8 to 3.6. The interaction of these conjugates with lectin concanavalin A was studied using three different methods: W quantitative precipitation in solution; (ii) sorption to concanavalin A immobilized on bead cellulose; and (iii) kinetic measurement of the interaction by surface plasmon resonance. Quantitative precipitation assay showed only negligible differences in the precipitation course of original mannan and the corresponding mannan-bovine serum albumin conjugates. Both the sorption method (equilibrium method) and the surface plasmon resonance measurement (kinetic method) demonstrates that the values of dissociation constant K-D of all synthetic neoglycoconjugates were within the range 10(-7)-10(-8) mol.L-1 (close to K-D = 10(-1) mol-L-1 determined by the sorption method for the original mannan). In conclusion, characterization of synthetic neoglycoconjugates confirmed that the method used for their preparation retained the ability of mannan moiety to interact with concanavalin A

Differentiation of Native and Reconstructed Ferritin using the MRI Gradient Echo Pulse Sequence

Ferritin is a biological iron storage biomacromolecule, consisting of a spherical protein shell (apoferritin) and mineral iron core. It plays a crucial role in the pathological processes of disrupted iron homeostasis followed by iron accumulation, linked with various disorders (e.g. neuroinflammation, neurodegeneration, cirrhosis, cancer, etc.) In vitro reconstructed ferritin, with the assistance of a non-invasive magnetic resonance imaging technique, has the potential to become a suitable biomarker of these pathological processes. Through gradient echo pulse sequencing, we were able to clearly distinguish between native (physiological) and reconstructed/iron-overloaded (pathological) ferritin, which can serve as a starting point for the development of a method for their differentiation. Such method is necessary for the early diagnosis of iron-based diseases

Effect of BSA Protein on the Contrast Properties of Magnetite Nanoparticles during MRI

The aim of the study was to establish whether there is a significant change in the MRI contrast of magnetite nanoparticles, after BSA protein binding on the surface of particles. The rationale is the applicability of this feature in clinical practice for the tracking of specific proteins which are often associated with various pathologies. Contrast agents could bind to this specific marker, with the change in MRI contrast indicating the presence of pathology. We found that changes in relative contrast acquired at low-field MRI offer potential for the differentiation of magnetite nanoparticles with and without BSA protein. However, the variations in the transverse relaxation time (T₂) and transverse relaxivity (r₂), acquired at high-field MRI, were too small to be applicable for biomedical applications