Els investigadors Lluïsa Vilaplana (Nb4D) i Eloy Ramos (Química teòrica i computacional) participaran en aquestScientific Vermouth, el 21 d’octubre a les 12:00 h, amb les següents ponències:
- Lluïsa Vilaplana – Antibody-mediated blocking of key Quorum Sensing molecules as a therapeutic strategy for the control of infectious diseases
Antimicrobial resistance is driving the search for alternative therapeutic strategies to combat bacterial infections. In this context, we are exploring the use of monoclonal antibodies to target key molecules involved in Pseudomonas aeruginosa virulence and bacterial communication through quorum sensing (QS), a regulatory system that plays a key role in bacterial pathogenicity. As an example of this approach, we evaluated the protective effect of mAb122, a monoclonal antibody specific to pyocyanin (PYO), a QS-regulated virulence factor involved in host-cell damage and immune dysregulation, in vitro using murine macrophages.
MAb122 significantly increased cell viability following PYO exposure, while its effects on cytokine production provided further insight into the impact of PYO and antibody treatment on the modulation of the host response. The seminar will also cover our ongoing work targeting other QS molecules, highlighting antibody-based targeting of bacterial communication and virulence as a potential complementary strategy to conventional antibiotics for the control of infectious diseases. - Eloy Ramos – How reliable are density functional approximations for vibrational properties?
Density functional theory (DFT) is the most widely used electronic-structure method because it enables the study of systems that are often beyond the reach of more expensive wavefunction-based approaches. Its favorable balance between accuracy and computational cost has made it a central tool for investigating vibrational properties of medium- and large-sized molecules across chemistry and materials science. However, recent studies have shown that many widely used density functional approximations (DFAs) are unreliable for these calculations, producing large errors in harmonic and anharmonic vibrational frequencies and intensities, vibronic spectra, and vibrational contributions to molecular response properties.
We show that these failures originate from spurious oscillations in energy and property derivatives along nuclear displacement coordinates, particularly for low-frequency modes. Although such errors can be reduced with very fine integration grids, this greatly diminishes the practical efficiency that makes DFT so useful [1,2]. Our results reveal that this grid sensitivity reflects a deeper flaw: many modern post-LDA DFAs are intrinsically ill-designed for vibrational properties because their exchange-correlation energy densities exhibit unphysical local oscillations. Importantly, we also show that this problem can be significantly alleviated in the B97 and wB97 families, opening the way to more reliable DFAs that preserve the broad applicability of DFT.
