Quercetin elevates p27Kip1 and arrests both primary and HPV16 E6/E7 transformed human keratinocytes in G1

Our previous work with primary bovine fibroblasts demonstrated that quercetin, a potent mutagen found in high levels in bracken fern (Pteridium aquilinum), arrested cells in G1 and G2/M, in correlation with p53 activation. The expression of bovine papillomavirus type 4 (BPV-4) E7 overcame this arrest and lead to the development of tumorigenic cells lines (Beniston et al., 2001). Given the possible link between papillomavirus infection, bracken fern in the diet and cancer of the upper gastrointestinal (GI) tract in humans, we investigated whether a similar situation would occur in human cells transformed by human papillomavirus type 16 (HPV-16) oncoproteins. Quercetin arrested primary human foreskin keratinocytes in G1. Arrest was linked to an elevation of the cyclin-dependent kinase inhibitor (cdki) p27Kip1. Expression of the HPV16 E6 and E7 oncoproteins in transformed cells failed to abrogate cell cycle arrest. G1 arrest in the transformed cells was also linked to an increase of p27Kip1 with a concomitant reduction of cyclin E-associated kinase activity. This elevation of p27Kip1 was due not only to increased protein half-life, but also to increased mRNA transcription

Phospholipid dependent mechanism of smp24, an α-helical antimicrobial peptide from scorpion venom

Determining the mechanism of action of antimicrobial peptides (AMPs) is critical if they are to be developed into the clinical setting. In recent years high resolution techniques such as atomic force microscopy (AFM) have increasingly been utilised to determine AMP mechanism of action on planar lipid bilayers and live bacteria. Here we present the biophysical characterisation of a prototypical AMP from the venom of the North African scorpion Scorpio maurus palmatus termed Smp24. Smp24 is an amphipathic helical peptide containing 24 residues with a charge of + 3 and exhibits both antimicrobial and cytotoxic activity and we aim to elucidate the mechanism of action of this peptide on both membrane systems. Using AFM, quartz crystal microbalance-dissipation (QCM-D) and liposomal leakage assays the effect of Smp24 on prototypical synthetic prokaryotic (DOPG:DOPC) and eukaryotic (DOPE:DOPC) membranes has been determined. Our data points to a toroidal pore mechanism against the prokaryotic like membrane whilst the formation of hexagonal phase non-lamellar phase structures is seen in eukaryotic like membrane. Also, phase segregation is observed against the eukaryotic membrane and this study provides direct evidence of the same peptide having multiple mechanisms of action depending on the membrane lipid composition

ARIA 2016: Care pathways implementing emerging technologies for predictive medicine in rhinitis and asthma across the life cycle

The Allergic Rhinitis and its Impact on Asthma (ARIA) initiative commenced during a World Health Organization workshop in 1999. The initial goals were (1) to propose a new allergic rhinitis classification, (2) to promote the concept of multi-morbidity in asthma a

Narrowband Searches for Continuous and Long-duration Transient Gravitational Waves from Known Pulsars in the LIGO-Virgo Third Observing Run

Isolated neutron stars that are asymmetric with respect to their spin axis are possible sources of detectable continuous gravitational waves. This paper presents a fully coherent search for such signals from eighteen pulsars in data from LIGO and Virgo's third observing run (O3). For known pulsars, efficient and sensitive matched-filter searches can be carried out if one assumes the gravitational radiation is phase-locked to the electromagnetic emission. In the search presented here, we relax this assumption and allow both the frequency and the time derivative of the frequency of the gravitational waves to vary in a small range around those inferred from electromagnetic observations. We find no evidence for continuous gravitational waves, and set upper limits on the strain amplitude for each target. These limits are more constraining for seven of the targets than the spin-down limit defined by ascribing all rotational energy loss to gravitational radiation. In an additional search, we look in O3 data for long-duration (hours-months) transient gravitational waves in the aftermath of pulsar glitches for six targets with a total of nine glitches. We report two marginal outliers from this search, but find no clear evidence for such emission either. The resulting duration-dependent strain upper limits do not surpass indirect energy constraints for any of these targets. © 2022. The Author(s). Published by the American Astronomical Society