Effectiveness of Interval vs. Endurance Training to Minimize Asthmatic Symptoms in Recreationally Active Adults

The prevalence of asthma is on the rise, affecting the quality of life of those who suffer from this condition. There are several treatments for asthma, exercise being one of the most affordable, while also offering other physiologic benefits. High intensity interval training (HIIT) consists of short bouts of maximal intensity exercise, followed by short periods of recovery. Endurance training consists of continuous, steady-state aerobic exercise, usually around 70% to 80% of maximal heart rate for 30 to 60 minutes in duration. Improvements in asthmatic symptoms have been seen utilizing both training protocols; however, most of the participants in these studies have been children. The purpose of this study was to determine if exercise will improve asthmatic symptoms of recreationally active adults, and to determine if there is a difference in interval and endurance training protocols in terms of asthmatic symptoms. It was hypothesized that exercise will improve asthmatic symptoms; however, due to lack of recruitment, the second aim of this study was not addressed. One recreationally active adult, 26 years of age, with no other chronic diseases, was recruited through the use of flyers. The participant was informed of the risks and benefits before partaking in any training protocol. Due to the fact that only one participant was recruited and time constraints to conduct a crossover design study (as was originally intended), the participant was randomly assigned to a six-week endurance protocol. Biometric and pulmonary measurements were taken before and after the protocol. It may appear that there was a slight decrease in pulmonary functions following the six-week endurance protocol; however, the measurements are likely within normal variation. Because this was a case study, no statistical analyses could be performed to determine statistical significance.M.S., Human Nutrition -- Drexel University, 201

Synapse-Associated Expression of an Acetylcholine Receptor-Inducing Protein, ARIA/Heregulin, and Its Putative Receptors, ErbB2 and ErbB3, in Developing Mammalian Muscle

AbstractDeveloping motor axons induce synaptic specializations in muscle fibers, including preferential transcription of acetylcholine receptor (AChR) subunit genes by subsynaptic nuclei. One candidate nerve-derived signaling molecule is AChR-inducing activity (ARIA)/heregulin, a ligand of the erbB family of receptor tyrosine kinases. Here, we asked whether ARIA and erbB kinases are expressed in patterns compatible with their proposed signaling roles. In developing muscle, ARIA was present not only at synaptic sites, but also in extrasynaptic regions of the muscle fiber. ARIA was synthesized, rather than merely taken up, by muscle cells, as indicated by the presence of ARIA mRNA in muscle and of ARIA protein in a clonal muscle cell line. ARIA-responsive myotubes expressed both erbB2 and erbB3, but little EGFR/erbB1 or erbB4. In adults, erbB2 and erbB3 were localized to the postsynaptic membrane. ErbB3 was restricted to the postsynaptic membrane perinatally, at a time when ARIA was still broadly distributed. Thus, our data are consistent with a model in which ARIA interacts with erbB kinases on the muscle cell surface to provide a local signal that induces synaptic expression of AChR genes. However, much of the ARIA is produced by muscle, not nerve, and the spatially restricted response may result from the localization of erbB kinases as well as of ARIA. Finally, we show that erbB3 is not concentrated at synaptic sites in mutant mice that lack rapsyn, a cytoskeletal protein required for AChR clustering, suggesting that pathways for synaptic AChR expression and clustering interact

An atypical receiver domain controls the dynamic polar localization of the Myxococcus xanthus social motility protein FrzS

The Myxococcus xanthus FrzS protein transits from pole-to-pole within the cell, accumulating at the pole that defines the direction of movement in social (S) motility. Here we show using atomic-resolution crystallography and NMR that the FrzS receiver domain (RD) displays the conserved switch Tyr102 in an unusual conformation, lacks the conserved Asp phosphorylation site, and fails to bind Mg2+ or the phosphoryl analogue, Mg2+·BeF3. Mutation of Asp55, closest to the canonical site of RD phosphorylation, showed no motility phenotype in vivo, demonstrating that phosphorylation at this site is not necessary for domain function. In contrast, the Tyr102Ala and His92Phe substitutions on the canonical output face of the FrzS RD abolished S-motility in vivo. Single-cell fluorescence microscopy measurements revealed a striking mislocalization of these mutant FrzS proteins to the trailing cell pole in vivo. The crystal structures of the mutants suggested that the observed conformation of Tyr102 in the wild-type FrzS RD is not sufficient for function. These results support the model that FrzS contains a novel ‘pseudo-receiver domain’ whose function requires recognition of the RD output face but not Asp phosphorylation