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  • Author: Wenliang Zhang x
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Yang Zhang, Weimin Zhang, Huiyi Yang, Wenliang Zhou, Chaoqun Hu and Lihong Zhang

Previously, the ricefield eel (Monopterus albus) was speculated to have only one cytochrome p450 aromatase gene. In this study, however, the cDNAs encoding two distinct cytochrome p450 aromatases, cyp19a1a and cyp19a1b, were isolated. The genomic organizations of both cyp19 genes were conserved when compared with other teleosts. Northern blot detected an abundant expression of cyp19a1a in the ovary, and cyp19a1b in the hypothalamus. RT-PCR coupled with Southern blot showed that cyp19a1a was expressed predominantly in the gonads of both sexes, with higher levels in the ovary than testis, while cyp19a1b was expressed in all the tissues examined in the male, but only in the brain and pituitary in the female. The levels of cyp19a1a mRNA in the ovary were increased significantly during vitellogenesis, but decreased significantly at mature stage. The levels of cyp19a1b mRNA in the brain and pituitary did not vary significantly during vitellogenesis. As ovarian development shifted from vitellogenesis to maturation, the levels of cyp19a1b mRNA was decreased significantly in the brain, but increased significantly in the pituitary. During natural sex change from female to male, the levels of cyp19a1a mRNA in the gonad were significantly decreased. The levels of cyp19a1b mRNA in the hypothalamus were significantly increased at the early intersexual phase, whereas the expression levels in the pituitary were significantly decreased at the intersexual phases. Taken together, these results showed a novel sexual dimorphism of cyp19a1b mRNA tissue distribution, and both CYP19 genes were associated with the ovarian development and natural sex change of the ricefield eel.

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Baiyang You, Yaoshan Dun, Wenliang Zhang, Lingjun Jiang, Hui Li, Murong Xie, Yuan Liu and Suixin Liu

Mitochondrial quality control (MQC) and function are determinants for cellular energy metabolism, and their disorders are reported to play an important role in the development of insulin resistance (IR). Salidroside was reported to have beneficial effects on MQC through AMPK pathway; however, it is unknown whether salidroside exerts anti-IR effect with this action. This study sought to investigate the effects of salidroside on IR with an exploration of the mechanisms of its action. Experimental IR models were adopted in high-fat-diet (HFD)-fed mice and palmitate-treated C2C12 myotubes, respectively. Blood levels of glucose and insulin as well as cellular glucose uptake were determined, and mitochondrial function and MQC-associated parameters and reactive oxygen species (ROS) production were analyzed based on treatments with the activator (AICAR), inhibitors (compound C and EX-527) or specific siRNA of Ampk/Sirt1 and mitochondrial ROS scavenger (mito-TEMPO). Protein expression level was determined by Western blot, cellular observation by transmission electron microscope and ROS production by functional analysis kits. Salidroside reduced IR and activated insulin signaling along with the stimulation of AMPK/SIRT1 signaling and downstream regulation of MQC and ROS production. These salidroside effects were comparable to those of AICAR and could be prevented by AMPK/SIRT1 inhibitors or siRNAs, respectively. Salidroside reduces IR and regulates MQC and ROS production by activating AMPK/SIRT1 signaling pathway. Since IR is a critical issue for public health, to explore a potent agent against IR is of high interest. The anti-IR effects of salidroside warrant further experimental and clinical studies.