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Fatty acid oxidation of cumulus-oocyte complex (COC) provides sufficient energy for oocyte maturation. But, the relationship between fatty acid oxidation and oxidative stress in aging follicles, as well as the effect of putrescine, is still unclear. The porcine COCs were randomly divided into four groups and cultured in in vitro maturation (IVM) medium with or without 1 mmol/L putrescine, with 50 μmol/L hydrogen peroxide (H 2 O 2) or with 50 μmol/L H 2 O 2 plus 1 mmol/L putrescine. Oocyte maturation was assessed by the first polar body extrusion. The expressions of genes involved in fatty acid oxidation were detected, and the mitochondrial function was analyzed by themembrane potential. The maturation rate of oocyte was significantly lower in the H 2 O 2 group when compared with the control group (P ＜0.001), and putrescine significantly increased this rate in the H 2 O 2 plus putrescine group when compared with the H 2 O 2 group (P ＜0.001). The expressions of LKB1, STRAD, ACC2, AMPKα1 and AMPKα2 mRNAs in cumulus cells (CCs) were significantly downregulated by H 2 O 2 treatment, and partly rescued by putrescine addition (P ＜0.05–0.001). However, the changes of LKB1, STRAD, ACC2, AMPKα1 and AMPKα2 mRNAs in oocytes were inapparent. The mitochondrial membrane potential of CCs in the H 2 O 2 group was significantly lower than that in the control group, while putrescine addition significantly increased the mitochondrial membrane potential (P ＜0.001). The decrease of oocyte maturation due to oxidative stress is related with the decreased fatty acid oxidation, and putrescine may alleviate the COCs damage via improving fatty acid oxidation. • Fatty acid oxidation of cumulus-oocyte complex provides sufficient energy for oocyte maturation. • The decrease of oocyte maturation due to oxidative stress is related with the decreased fatty acid oxidation. • Putrescine may alleviate the cumulus-oocyte complex damage via improving fatty acid oxidation. [ABSTRACT FROM AUTHOR]

Abstract: Several families of kinases work together to ensure the rate and precision of mitosis. Aurora-B is an important serine/threonine kinase required for chromosome segregation and cytokinesis. Identification of Aurora-B substrates will help to enhance our understanding of the molecular mechanism of mitosis. Through a yeast two-hybrid screen, we found a novel partner of Aurora-B, Septin1, belonging to a conserved family of GTPase proteins that localize to the cleavage furrow and are involved in cytokinesis. We confirmed this interaction using Co-immunoprecipitation experiments in mammalian cells and GST-pull-down analysis in vitro. Moreover, Aurora-B can phosphorylate Septin1 in vitro. We identified that Ser248, Ser307, and Ser315 are the main phosphorylation sites in Septin1. These two proteins partially co-localize to the midbody during cytokinesis. So, it is possible that Septin1’s role in the regulation of cytokinesis is related to its phosphorylation by Aurora-B. Unlike previous reports that Septins function in cytokinesis and localize to the cleavage furrow, we found that Septin1 localizes to the spindle pole throughout mitosis, indicating that Septin1 may function in chromosome segregation as well. [Copyright &y& Elsevier]