Dynamics of salivary proteins and metabolites during extreme endurance sports - a case study.

As noninvasively accessible body fluid, saliva is of growing interest in diagnostics. To exemplify the diagnostic potential of saliva, we used a mass spectrometry-based approach to gain insights into adaptive physiological processes underlying long-lasting endurance work load in a case study. Saliva was collected from male and female athlete at four diurnal time points throughout a 1060 km nonstop cycling event. Total sampling time covered 180 h comprising 62 h of endurance cycling as well as reference samples taken over 3 days before the event, and over 2 days after. Altogether, 1405 proteins and 62 metabolites were identified in these saliva samples, of which 203 could be quantified across the majority of the sampling time points. Many proteins show clear diurnal abundance patterns in saliva. In many cases, these patterns were disturbed and altered by the long-term endurance stress. During the stress phase, metabolites of energy mobilization, such as creatinine and glucose were of high abundance, as well as metabolites with antioxidant functions. Lysozyme, amylase, and proteins with redox-regulatory function showed significant increase in average abundance during work phase compared to rest or recovery phase. The recovery phase was characterized by an increased abundance of immunoglobulins. Our work exemplifies the application of high-throughput technologies to understand adaptive processes in human physiology.

Cell motility as persistent random motion: theories from experiments.

Experimental time series for trajectories of motile cells may contain so much information that a systematic analysis will yield cell-type-specific motility models. Here we demonstrate how, using human keratinocytes and fibroblasts as examples. The two resulting models reflect the cells' different roles in the organism, it seems, and show that a cell has a memory of past velocities. They also suggest how to distinguish quantitatively between various surfaces' compatibility with the two cell types.

The effects of collagen type I topography on myoblasts in vitro.

Cells respond to a variety of cues from their environment, which can include chemical, mechanical, and topographical signals. The differentiation of myoblasts requires a combination of signals. Myoblast fusion is strongly influenced by the chemical nature of the surrounding matrix and can be affected by mechanical stimulation. Studies also have shown that a large variety of cell types also are influenced by details of surface topography of a substrate as small as 44 nm. Cells grown on a collagen-coated surface differentiate more readily than those grown in the absence of the extracellular matrix protein. It is not known whether the effects of myoblast interaction with collagen are due solely to chemical interactions or if myoblasts also respond to the topography of collagen type I fibers. To determine the importance of collagen-generated topographical signals on myoblast development, cells were cultured and differentiated in vitro on surfaces that had been coated with either soluble collagen type I or fibrous collagen type I. Both surfaces present the same chemical interactions, but the additional topographical signals lead to differences in cell morphology, adhesion, spreading rates and, proliferation. Cells on the fibrous form of collagen are more stellate, form more adhesion plaques, spread faster, and proliferate at a faster, rate than cells on a surface of soluble collagen. Our data indicate that topographical signals play a role in early muscle development, but that other or additional signaling pathways regulate differentiation.