Nanostructural and nanomechanical alterations of photosensitized lipid membranes due to light induced formation of reactive oxygen species.

Photosensitization has a wide range of applications in vastly distant fields. Three key components must be present at the same time to trigger the related photodynamic effect: light, the photosensitizer (PS) and oxygen. Irradiating the sensitizer leads to the formation of reactive oxygen species (ROS).

Characterization of a G-quadruplex from hepatitis B virus and its stabilization by binding TMPyP4, BRACO19 and PhenDC3.

Specific guanine rich nucleic acid sequences can form non-canonical structures, like the four stranded G-quadruplex (GQ). We studied the GQ-forming sequence (named HepB) found in the genome of the hepatitis B virus. Fluorescence-, infrared- and CD-spectroscopy were used.

Pressure Perturbation Studies of Noncanonical Viral Nucleic Acid Structures.

G-quadruplexes are noncanonical structures formed by guanine-rich sequences of the genome. They are found in crucial loci of the human genome, they take part in the regulation of important processes like cell proliferation and cell death. Much less is known about the subjects of this work, the viral G-quadruplexes.

Negative volume changes of human G-quadruplexes at unfolding.

G-quadruplexes are tetrahelical structures. They are important targets for anti-cancer drugs, since they are situated at crucial positions within the genome. We studied the volumetric properties of the unfolding of three G-quadruplexes in the presence of potassium ion.

Revealing unfolding steps and volume changes of human telomeric i-motif DNA.

Cytosine rich DNA sequences can fold into a non-canonical four stranded intercalated i-motif structure. We investigated Htel-iM, an i-motif structure of the human telomeric DNA region that plays an important role in cell division, cancer diseases and aging. A high pressure up to 1 Gpa was applied to reveal the volumetric changes during unfolding.

Crosslinked Hyaluronic Acid Gels with Blood-Derived Protein Components for Soft Tissue Regeneration.

Hyaluronic acid (HA) is an ideal initial material for preparing hydrogels, which may be used as scaffolds in soft tissue engineering based on their advantageous physical and biological properties. In this study, two crosslinking agents, divinyl sulfone (DVS) and butanediol diglycidyl ether, were used to investigate their effect on the properties of HA hydrogels. As HA hydrogels alone do not promote cell adhesion on the scaffold, fibrin and serum from platelet-rich fibrin (SPRF) were combined with the scaffold; the aim was to create a material intended to be used as soft tissue implant that facilitates new tissue formation, and degrades over time.

Structural and nanomechanical comparison of epitaxially and solution-grown amyloid β25-35 fibrils.

Aβ25-35, the fibril-forming, biologically active toxic fragment of the full-length amyloid β-peptide also forms fibrils on mica by an epitaxial assembly mechanism. Here we investigated, by using atomic force microscopy, nanomechanical manipulation and FTIR spectroscopy, whether the epitaxially grown fibrils display structural and mechanical features similar to the ones evolving under equilibrium conditions in bulk solution. Unlike epitaxially grown fibrils, solution-grown fibrils displayed a heterogeneous morphology and an apparently helical structure.

High pressure effects on allergen food proteins.

There are several proteins, which can cause allergic reaction if they are inhaled or ingested. Our everyday food can also contain such proteins. Food allergy is an IgE-mediated immune disorder, a growing health problem of great public concern.

Different pressure-temperature behavior of the structured and unstructured regions of titin.

Contrary to the classical view, according to which all proteins adopt a specific folded conformation necessary for their function, intrinsically unstructured proteins (IUPs) display random-coil-like conformation under physiological conditions. We compared the structured and unstructured domains from titin, a giant protein responsible for striated-muscle elasticity. A 171-residue-long fragment (polyE) of the disordered PEVK domain, and an Ig domain (I27) with ordered structure were investigated.

Pressure-temperature stability, Ca2+ binding, and pressure-temperature phase diagram of cod parvalbumin: Gad m 1.

Fish allergy is associated with IgE-mediated hypersensitivity reactions to parvalbumins, which are small calcium-binding muscle proteins and represent the major and sole allergens for 95% of fish-allergic patients. We performed Fourier transform infrared and tryptophan fluorescence spectroscopy to explore the pressure-temperature (p-T) phase diagram of cod parvalbumin (Gad m 1) and to elucidate possible new ways of pressure-temperature inactivation of this food allergen. Besides the secondary structure of the protein, the Ca(2+) binding to aspartic and glutamic acid residues was detected.

Pressure and temperature stability of the main apple allergen Mal d1.

High-pressure Fourier-transform infrared (FTIR) spectroscopy was used to determine the pressure and temperature stability of Mal d1. This study was triggered by contradictory results in the literature regarding the success of pressure treatment in the destruction of the allergen. The protein unfolded at 55°C when heated at normal atmospheric pressure.