The demand for highly efficient macromolecular drugs, used in the treatment of many severe diseases, is continuously increasing. However, the hydrophilic character and large molecular size of these drugs significantly limit their ability to permeate across cellular membranes and thus impede the drugs in reaching their target sites in the body. Cell-penetrating peptides (CPP) have gained attention as promising drug excipients, since they can facilitate drug permeation across cell membranes constituting a major biological barrier. Fluorophores are frequently covalently conjugated to CPPs to improve detection, however, the ensuing change in physico-chemical properties of the CPPs may alter their biological properties. With complementary biophysical techniques, we show that the mode of biomembrane interaction may change considerably upon labeling of the CPP penetratin (PEN) with a fluorophore. Fluorophore-PEN conjugates display altered modes of membrane interaction with increased insertion into the core of model cell membranes thereby exerting membrane-thinning effects. This is in contrast to PEN, which localizes along the head groups of the lipid bilayer, without affecting the thickness of the lipid tails. Particularly high membrane disturbance is observed for the two most hydrophobic PEN conjugates; rhodamine B or 1-pyrene butyric acid, as compared to the four other tested fluorophore-PEN conjugates.
Cell-penetrating peptides constitute efficient delivery vectors, and studies of their uptake and mechanism of translocation typically involve fluorophore-labeled conjugates. In the present study, the influence of a number of specific fluorophores on the physico-chemical properties and uptake-related characteristics of penetratin were studied. An array of seven fluorophores belonging to distinct structural classes was examined, and the impact of fluorophore labeling on intracellular distribution and cytotoxicity was correlated to the physico-chemical properties of the conjugates. Exposure of several mammalian cell types to fluorophore-penetratin conjugates revealed a strong structure-dependent reduction in viability (1.5- to 20-fold lower IC values as compared to those of non-labeled penetratin). Also, the degree of less severe effects on membrane integrity, as well as intracellular distribution patterns differed among the conjugates. Overall, neutral hydrophobic fluorophores or negatively charged fluorophores conferred less cytotoxicity as compared to the effect exerted by positively charged, hydrophobic fluorophores. The latter conjugates, however, exhibited less membrane association and more clearly defined intracellular distribution patterns. Thus, selection of the appropriate flurophore is critical.
Across the European research area and beyond, efforts are being mobilized to align research and innovation processes and products with societal values and needs, and to create mechanisms for inclusive priority setting and knowledge production. A central concern is how to foster a culture of "Responsible Research and Innovation" (RRI) among scientists and engineers. This paper focuses on RRI teaching at higher education institutions. On the basis of interviews and reviews of academic and policy documents, it highlights the generic aspects of teaching aimed at invoking a sense of care and societal obligation, and provides a set of exemplary cases of RRI-related teaching. It argues that the Aristotelian concept of phronesis can capture core properties of the objectives of RRI-related teaching activities. Teaching should nurture the students' capacity in terms of practical wisdom, practical ethics, or administrative ability in order to enable them to act virtuously and responsibly in contexts which are often characterized by uncertainty, contention, and controversy.
After a decade of efforts to mainstream Responsible Research and Innovation (RRI) across Europe, the policy momentum is now uncertain. We explore how 217 organisations perceive responsibility in relation to their work, what mechanisms they apply to promote responsible practices, and what hindrances to promoting RRI they observe. Most organisations are unfamiliar with RRI but employ diverse perceptions of responsibility and mechanisms to promote it nonetheless. Civil society organisations are primarily outward oriented; collaborating with others and hosting science events. Private companies are more internally focussed and more likely to formalise this effort in strategies and internal guidelines. Universities resemble private companies, while private and public funders use funding-specific tools to incentivise responsible practices. Our results suggest that RRI is still poorly institutionalised and that some areas lack attention among actors in the research and innovation systems. Future policy endeavours might benefit from addressing deficits and tapping into existing perceptions of responsibility.
Urinary excretion of selenium after ingestion of isotope labeled selenite and selenate was studied in seven healthy volunteers, 4 men and 3 women (age 28-50 years). An aqueous solution containing 330 μL (82)Se-selenate (corresponding to 74.3 μg (82)Se) was given orally and urine samples were subsequently collected during the following 24 hours. The scheme was repeated four weeks later with a 280 μL (82)Se-selenite solution (corresponding to 74.4 μg (82)Se). The amount of total Se in the urine samples was determined by inductively coupled mass spectrometry. The mean total urinary excretion of (82)Se following (82)Se-selenate administration was 33.7% (range 15.6-42.5%) while the mean total excretion of (82)Se after (82)Se-selenite administration was 3.2% (range 2.8-3.9%) of the ingested amount. LC-ICPMS analysis of the urine samples showed that the majority of the selenium excreted after selenate ingestion was unchanged selenate for 6 of the individuals while one individual had metabolized a fraction (approx. 20%) of the selenate to selenosugar. Ingestion of 10 times larger doses of selenite in two individuals resulted in 13-23% excretion primarily excreted as selenosugar. These results show that the human metabolic pathways of selenite and selenate are different and indicate that not all selenate, although well absorbed, may be available for the beneficial health effects.
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