Effects of chitosan and oligochitosan on development and mitochondrial function of Rhizopus stolonifer.
The antifungal activities of chitosan and oligochitosan have been used to control postharvest decay of the fruits. The effect of chitosan and oligochitosan on mycelium growth, spore germination, and mitochondrial function of Rhizopus stolonifer was evaluated in order to establish a connection between fungus development and the main organelle in charge to provide energy to the cell. The mycelium growth of R. stolonifer was significantly reduced on minimum media amended with chitosan or oligochitosan. The highest antifungal indexes were obtained on media containing chitosan or oligochitosan at 2.0 mg ml(-1). Microscopic observation showed that chitosan and oligochitosan affected the spore germination and hyphae morphology. Both polymers increased oxygen consumption of R. stolonifer. Respiratory activity was restored with NADH in permeabilized treated and untreated cells, and was inhibited with rotenone and flavones. Complex III and IV were inhibited by antimycin A and cyanide, respectively, in treated and untreated cells. Chitosan and oligochitosan increased NADH dehydrogenase activity in isolated mitochondria. However, there were not changes in the cytochrome c oxidase and ATPase activities by effect of these polymers. These results suggest that both chitosan and oligochitosan affect the development of R. stolonifer and might be implicated in the mitochondrial dysfunction.
ENCB, Instituto Politécnico Nacional México, México, D. F., Mexico.
Leobarda
L
Robles-Martínez
María Guadalupe
MG
Guerra-Sánchez
Ana Niurka
AN
Hernández-Lauzardo
Juan Pablo
JP
Pardo
Miguel Gerardo
MG
Velázquez-del Valle
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000935:Antifungal Agents / Q000378:metabolism*; D048271:Chitosan / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry; D003576:Electron Transport Complex IV / Q000378:metabolism; D008853:Microscopy; D008928:Mitochondria / Q000187:drug effects* / Q000502:physiology*; D025282:Mycelium / Q000166:cytology / Q000187:drug effects / Q000254:growth & development; D009243:NAD / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D012233:Rhizopus / Q000166:cytology / Q000187:drug effects* / Q000254:growth & development*; D013172:Spores, Fungal / Q000166:cytology / Q000187:drug effects / Q000254:growth & development
D000935:Antifungal Agents; D003470:Culture Media; D009243:NAD; D048271:Chitosan; D003576:Electron Transport Complex IV; D000251:Adenosine Triphosphatases; D010100:Oxygen
Chitosan; Mitochondrial respiration; Oligochitosan; Oxygen consumption; Rhizopus stolonifer