Proteomic and carbonylation profile analysis of rat skeletal muscles following acute swimming exercise

Previous studies by us and other groups characterized protein expression variation following long-term moderate training, whereas the effects of single bursts of exercise are less known. Making use of a proteomic approach, we investigated the effects of acute swimming exercise (ASE) on protein expression and carbonylation patterns in two hind limb muscles: the Extensor Digitorum Longus (EDL) and the Soleus, mostly composed of fast-twitch and slow-twitch fibres, respectively. Carbonylation is one of the most common oxidative modifications of proteins and a marker of oxidative stress. In fact, several studies suggest that physical activity and the consequent increase in oxygen consumption can lead to increase in reactive oxygen and nitrogen species (RONS) production, hence the interest in examining the impact of RONS on skeletal muscle proteins following ASE. Results indicate that protein expression is unaffected by ASE in both muscle types. Unexpectedly, the protein carbonylation level was reduced following ASE. In particular, the analysis found 31 and 5 spots, in Soleus and EDL muscles respectively, whose carbonylation is reduced after ASE. Lipid peroxidation levels in Soleus were markedly reduced as well. Most of the decarbonylated proteins are involved either in the regulation of muscle contractions or in the regulation of energy metabolism. A number of hypotheses may be advanced to account for such results, which will be addressed in future studies

Proteomic and carbonylation profile analysis of rat skeletal muscles following acute swimming exercise.

Previous studies by us and other groups characterized protein expression variation following long-term moderate training, whereas the effects of single bursts of exercise are less known. Making use of a proteomic approach, we investigated the effects of acute swimming exercise (ASE) on protein expression and carbonylation patterns in two hind limb muscles: the Extensor Digitorum Longus (EDL) and the Soleus, mostly composed of fast-twitch and slow-twitch fibres, respectively. Carbonylation is one of the most common oxidative modifications of proteins and a marker of oxidative stress. In fact, several studies suggest that physical activity and the consequent increase in oxygen consumption can lead to increase in reactive oxygen and nitrogen species (RONS) production, hence the interest in examining the impact of RONS on skeletal muscle proteins following ASE. Results indicate that protein expression is unaffected by ASE in both muscle types. Unexpectedly, the protein carbonylation level was reduced following ASE. In particular, the analysis found 31 and 5 spots, in Soleus and EDL muscles respectively, whose carbonylation is reduced after ASE. Lipid peroxidation levels in Soleus were markedly reduced as well. Most of the decarbonylated proteins are involved either in the regulation of muscle contractions or in the regulation of energy metabolism. A number of hypotheses may be advanced to account for such results, which will be addressed in future studies

Exports vs. foreign direct investment: evidence from cross-country industry data

The recent process of globalization has been characterized by a rapid increase of foreign direct investments (FDIs), outpacing the simultaneous expansion of arms-length trade (exporting). Trade theory traces back different patterns of internationalization to differences in productivity levels between firms. As in Helpman et al. (2004), we argue that differences in productivity are affected by heterogeneity in firm size. However, we explicitly consider the number of large firms in a sector rather than the size dispersion. Moreover, previous literature performs single country analysis, whereas we extend our analysis to several developed as well as developing countries. By using comprehensive cross-section data on bilateral exports and FDIs (proxied by mergers and acquisitions) over the period 1994-2004, we explain differences across 57 manufacturing sectors in the relative incidence of trade and FDIs. Controlling for other factors affecting the patterns of internationalization and performing several sample splits and robustness tests, our results confirm that sectors with a higher number of large firms are associated with stronger incidence of FDIs relative to trade.Il recente processo di globalizzazione è stato caratterizzato dall’incremento degli investimenti diretti esteri (IDE) che ha superato di gran lunga la rapida e simultanea espansione delle esportazioni. La teoria sul commercio internazionale spiega i patterns di internazionalizzazione attraverso le differenze nei livelli di produttività tra le imprese. Compatibilmente con i risultati di Helpman et al. (2004), questo lavoro argomenta che le differenze di produttività tra le imprese sono determinate dall’eterogeneità tra le imprese in termini di dimensione. Tuttavia, questo lavoro considera esplicitamente il numero di imprese di grandi dimensioni presenti in ciascun settore, anziché la dispersione della dimensione. Inoltre, la letteratura esistente compie analisi specifiche per singoli paesi, mentre il nostro lavoro estende l’analisi a diversi paesi, sia sviluppati che in via di sviluppo. Utilizzando un dataset cross-section sulle esportazioni e gli IDE (misurati attraverso il valore delle fusioni e acquisizioni) bilaterali, per il periodo 1994-2004, il lavoro spiega le differenze nell’incidenza del commercio sugli IDE, tra 57 settori manifatturieri. Controllando per diversi fattori che incidono sui patterns di internazionalizzazione e riportando i risultati di diversi test di robustezza, il lavoro conferma che i settori caratterizzati da una maggiore presenza di imprese di grandi dimensioni presentano una più elevata incidenza degli IDE rispetto alle [email protected]@[email protected]