Photo-initiated rupture of azobenzene micelles to enable the spectroscopic analysis of antimicrobial peptide dynamics

Membrane mediated peptide conformational changes via photo-induced micelle disruption.

Determination of physiological parameters for endogenous glucose production in individuals using diurnal data

Background Triple tracer meal experiments used to investigate organ glucose-insulin dynamics, such as endogenous glucose production (EGP) of the liver are labor intensive and expensive. A procedure was developed to obtain individual liver related parameters to describe EGP dynamics without the need for tracers. Results The development used an existing formula describing the EGP dynamics comprising 4 parameters defined from glucose, insulin and C-peptide dynamics arising from triple meal studies. The method employs a set of partial differential equations in order to estimate the parameters for EGP dynamics. Tracer-derived and simulated data sets were used to develop and test the procedure. The predicted EGP dynamics showed an overall mean R2 of 0.91. Conclusions In summary, a method was developed for predicting the hepatic EGP dynamics for healthy, pre-diabetic, and type 2 diabetic individuals without applying tracer experiments.

The anorexia of aging: impact on health and quality of life

Malnutrition for the elderly is a serious threat to their health. An elderly malnourished person is more exposed to illness, to disability and to institutionalization. Among the causes of malnutrition there is also the reduction of food intake for reduced hunger. With aging many factors favor the prevalence of satiety with respect to the desire to eat. This condition has been defined as anorexia of aging. Gastric motility impairment, unbalanced central and gastrointestinal hormone and peptide dynamics, together with sensory deterioration, depression, social and iatrogenic factors may be found frequently among older person and cause anorexia. Reduced appetite and exaggerated feeling of satiety are also causes of deterioration of quality of life, due to the decrease in the pleasure of eating and the presence of unpleasant, early and prolonged sense of fullness. Understanding the mechanisms that facilitate anorexia could help eliminate reversible causes and reduce the effect of para-physiological changes at the basis of anorexia. With this approach, it would be possible to improve the nutritional status and, at the same time, the level of quality of life of aged people.

The Hidden Transition Paths During the Unfolding of Individual Peptides with a Confined Nanopore

A fundamental question in peptide folding/unfolding is how the peptide fleets through a set of transition states which dominate the dynamics of biomolecular folding path. Owing to their rapid duration and sub-nm structure difference, however, they have always been oversimplified because of limited instrumental resolution.^1-3 Moreover, the most experiments indicate a single fold pathway while the simulations suggest peptides owns the preference in multiple pathways. <a></a><a></a><a>Using the electrochemical confined effect of a solid-state nanopore, we measured the multiple transit paths of peptide inside nanopores. </a>Combining with Markov chain modelling, this new single-molecule technique is applied to clarify the 5 transition paths of the <a>β-hairpin </a>peptide which shows 4 nonequilibrium fluctuating stages. These results enable experimental access to previously obscured peptide dynamics which are essential to understand the misfolding in peptides. The statistical analysis of each peptide from high throughput shows that 78.5% of the peptide adopts the Pathways I during their folding/unfolding in a nanopore while 21.5% of the peptide undergoes the hidden folding/unfolding of transit Pathways II-IV. The frequency of the ionic fluctuation reveals a harmonic structure difference of the <a>metastable</a> peptide. Our results suggest the folding/unfolding of β-hairpin undergo four major structure vibrations which agree well with the theoretical expectation. These measurements provide a first look at the critical experiment picture of the mechanical folding/unfolding of a peptide, opening exciting avenues for the high <a></a><a>throughput</a> investigation of transition paths.

The Hidden Transition Paths During the Unfolding of Individual Peptides with a Confined Nanopore

A fundamental question in peptide folding/unfolding is how the peptide fleets through a set of transition states which dominate the dynamics of biomolecular folding path. Owing to their rapid duration and sub-nm structure difference, however, they have always been oversimplified because of limited instrumental resolution.^1-3 Moreover, the most experiments indicate a single fold pathway while the simulations suggest peptides owns the preference in multiple pathways. <a></a><a></a><a>Using the electrochemical confined effect of a solid-state nanopore, we measured the multiple transit paths of peptide inside nanopores. </a>Combining with Markov chain modelling, this new single-molecule technique is applied to clarify the 5 transition paths of the <a>β-hairpin </a>peptide which shows 4 nonequilibrium fluctuating stages. These results enable experimental access to previously obscured peptide dynamics which are essential to understand the misfolding in peptides. The statistical analysis of each peptide from high throughput shows that 78.5% of the peptide adopts the Pathways I during their folding/unfolding in a nanopore while 21.5% of the peptide undergoes the hidden folding/unfolding of transit Pathways II-IV. The frequency of the ionic fluctuation reveals a harmonic structure difference of the <a>metastable</a> peptide. Our results suggest the folding/unfolding of β-hairpin undergo four major structure vibrations which agree well with the theoretical expectation. These measurements provide a first look at the critical experiment picture of the mechanical folding/unfolding of a peptide, opening exciting avenues for the high <a></a><a>throughput</a> investigation of transition paths.