Flavonoids exclusively present in mycorrhizal roots of white clover exhibit a different effect on arbuscular mycorrhizal fungi than flavonoids exclusively present in non-mycorrhizal roots of white clover

The flavonoids 5,6,7,8,9-hydroxy chalcone, 3,7-hydroxy-4′methoxy flavone, 5,6,7,8-hydroxy-4′-methoxy flavone and 3,5,6,7,4′-hydroxy flavone can be detected only in non-mycorrhizal roots of white clover, but not in mycorrhizal roots, whereas the flavonoids acacetin, quercetin and rhamnetin are only present in mycorrhizal roots. We tested the effect of several concentrations of these compounds on spore germination, hyphal growth, hyphal branching, formation of clusters of auxiliary cells and of secondary spores of the arbuscular mycorrhizal fungi Gigaspora rosea, Gigaspora margarita, Glomus mosseae and Glomus intraradices. Our results indicate that depending on the flavonoid, the tested compounds are involved at different stages in the regulation of mycorrhization. This hypothesis is strengthened by their differing effect on several AM fungal growth parameters. Furthermore, our study provides more data on the AM fungus genus/species specificity of flavonoids. © 2005 Taylor & Francis.Fil:Scervino, J.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Ponce, M.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Godeas, A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Autophagy signaling in hypertrophied muscles of diabetic and control rats

Autophagy plays a vital role in cell homeostasis by eliminating nonfunctional components and promoting cell survival. Here, we examined the levels of autophagy signaling proteins after 7 days of overload hypertrophy in the extensor digitorum longus (EDL) and soleus muscles of control and diabetic rats. We compared control and 3‐day streptozotocin‐induced diabetic rats, an experimental model for type 1 diabetes mellitus (T1DM). EDL muscles showed increased levels of basal autophagy signaling proteins. The diabetic state did not affect the extent of overload‐induced hypertrophy or the levels of autophagy signaling proteins (p‐ULK1, Beclin‐1, Atg5, Atg12‐5, Atg7, Atg3, LC3‐I and II, and p62) in either muscle. The p‐ULK‐1, Beclin‐1, and p62 protein expression levels were higher in the EDL muscle than in the soleus before the hypertrophic stimulus. On the contrary, the soleus muscle exhibited increased autophagic signaling after overload‐induced hypertrophy, with increases in Beclin‐1, Atg5, Atg12‐5, Atg7, Atg3, and LC3‐I expression in the control and diabetic groups, in addition to p‐ULK‐1 in the control groups. After hypertrophy, Beclin‐1 and Atg5 levels increased in the EDL muscle of both groups, while p‐ULK1 and LC3‐I increased in the control group. In conclusion, the baseline EDL muscle exhibited higher autophagy than the soleus muscle. Although TDM1 promotes skeletal muscle mass loss and strength reduction, it did not significantly alter the extent of overload‐induced hypertrophy and autophagy signaling proteins in EDL and soleus muscles, with the two groups exhibiting different patterns of autophagy activation