biophysics

The oligomeric assembly of the phosphodiesterase-5 is a mixture of dimers and tetramers: a putative role in the regulation of function

Background: Phosphodiesterases (PDEs) are a superfamily of evolutionary conserved cyclic nucleotides (cAMP/cGMP) hydrolysing enzymes, components of transduction pathways regulating crucial aspects of cell life. PDE5, one of these families, is the molecular target of several drugs used to treat erectile dysfunction and pulmonary hypertension. Despite its medical relevance, PDE5 macromolecular structure has only been solved for the isolated regulatory and catalytic domains.

Exploring the applicability of nano-poration for remote control in smart drug delivery systems

Smart drug delivery systems represent an interesting tool to significantly improve the efficiency and the precision in the treatment of a broad category of diseases. In this context, a drug delivery mediated by nanosecond pulsed electric fields seems a promising technique, allowing for a controlled release and uptake of drugs by the synergy between the electropulsation and nanocarriers with encapsulated drugs.

Geometrical characterization of an electropore from water positional fluctuations

We present here a new method for calculating the radius of a transmembrane pore in a phospholipid bilayer. To compare size-related properties of pores in bilayers of various compositions, generated and maintained under different physical and chemical conditions, reference metrics are needed. Operational metrics can be associated with some observed behavior. For example, pore size can be defined by the largest object that will pass through the length of the pore.

Microwave thermal ablation. Effects of tissue properties variations on predictive models for treatment planning

Microwave thermal ablation (MTA) therapy for cancer treatments relies on the absorption of electromag- netic energy at microwave frequencies to induce a very high and localized temperature increase, which causes an irreversible thermal damage in the target zone. Treatment planning in MTA is based on exper- imental observations of ablation zones in ex vivo tissue, while predicting the treatment outcomes could be greatly improved by reliable numerical models.

Aqueous polythiophene electrosynthesis. A new route to an efficient electrode coupling of PQQ-dependent glucose dehydrogenase for sensing and bioenergetic applications

In this study, polythiophene copolymers have been used as modifier for electrode surfaces in order to allow the immobilization of active pyrroloquinoline quinone dependent glucose dehydrogenase (PQQ-GDH) and to simultaneously improve the direct electrical connection of the enzyme with the electrode. Polymer films are electrosynthesized in aqueous solution without the need of surfactants onto carbon nanotubes modified gold electrodes from mixtures of 3-thiopheneacetic acid (ThCH2CO2H) and 3-methoxythiophene (ThOCH3) using a potentiostatic pulse method.

Phenotypic transitions enacted by simulated microgravity do not alter coherence in gene transcription profile

Cells in simulated microgravity undergo a reversible morphology switch, causing the appearance of two distinct phenotypes. Despite the dramatic splitting into an adherent-fusiform and a floating-spherical population, when looking at the gene-expression phase space, cell transition ends up in a largely invariant gene transcription profile characterized by only mild modifications in the respective Pearson’s correlation coefficients.

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