The Effects of Physical Exercise on Saliva Composition. A Comprehensive Review

Saliva consists of organic and inorganic constituents. During exercise, analysis of the saliva can provide valuable information regarding training stress, adaptation and exercise performance. The objective of the present article was to review the effect of physical exercise on saliva composition. The shift in the composition of the saliva, during and after a workout, reflects the benefits of exercise, its potential risks and the capability of the saliva to serve as a health indicator. The type and the frequency of training, the physical condition and the athletes’ general health influence the hormones, immunoglobulins and saliva enzymes. The correlation between saliva and physical exercise has to be further investigated and the available knowledge to be applied for the benefit of the athletes during sports activities.

Photoaffinity capture compounds to profile the Magic Spot Nucleotide interactomes

Magic Spot Nucleotides (MSN) regulate the stringent response, a highly conserved bacterial stress adaptation mechanism, enabling survival when confronted with adverse external challenges. In times of antibiotic crisis, a detailed understanding of the stringent response is of critical importance, as potentially new targets for pharmacological intervention could be identified. In this study, we delineate the MSN interactome in Escherichia coli and Salmonella typhimurium cell lysates applying a family of trifunctional photoaffinity capture compounds. We introduce different MSN probes covering diverse phosphorylation patterns, such as pppGpp, ppGpp, and pGpp. Our chemical proteomics approach provides datasets of diverse putative MSN receptors both from cytosolic and membrane fractions that, upon validation, unveil new MSN targets. We find, for example, that the dinucleoside polyphosphate hydrolase activity of the non-Nudix hydrolase ApaH is potently inhibited by pppGpp, which itself is converted to pGpp by ApaH. The photoaffinity capture compounds described herein will be useful to identify MSN interactomes under varying conditions and across bacterial species.

Couchsurfing with Bateson: An ecology of digital platforms

Digital platforms radically alter socio-economic and organizational patterns. In an ecological sense, they enable the rapid extension of tolerance limits by digitally scaling variables such as the availability of accommodation or labour. However, such maximization of specific variables in a complex ecology bears the danger of pathological runaway patterns. In our paper we draw on the work of Gregory Bateson to outline an analytical approach for the study of digital platforms as ecological phenomena, focussing on the effects of digitalization on the context in which platforms operate. To study such meta-patterns, we elaborate three interrelated concepts: stress, adaptation and budgets of flexibility. We exemplify these ideas through a longitudinal study of the early digital platform Couchsurfing and develop implications for our understanding of technology and organization.