ABSTRACT
[Objective]To investigate the effect of desuccinylase Sirtuin5 (SIRT5) on receptor-interacting protein 140 (RIP140)- mediated metabolic dysfunction in cardiomyocytes.[Methods]RIP140 was overexpressed by Adenovirus infection and SIRT5 was overexpressed by plasmid transfection. RIP140 and SIRT5 were knocked down by siRNA interference. The expression of RIP140 and SIRT5 were measured by qRT-PCR and western blot. The transcription levels of mitochondrial DNA-encoded genes were detected by qRT-PCR. Mitochondrial membrane potential was detected by tetramethylrhodamine ethyl ester(TMRE)fluorescence anl?ysis. Cellular oxygen consumption and ATP production were investigated by assay kits. All data are from at least three independent ex?periments.[Results]RIP140 overexpression significantly attenuated SIRT5 expression(P<0.05),whereas knockdown of endogenous RIP140 elevated SIRT5 expression(P<0.05)in cardiomyocytes. Superabundant RIP140 also induced hypersuccinylation of mitochon?drial proteins,suggesting RIP140 could repress the desuccinylase activity of SIRT5. Moreover,SIRT5 overexpression reversed RIP140-mediated mitochondrial dysfunction and energy metabolic impairment ,such as repression of mitochondrial DNA-encoded genes(P<0.05),decrease of mitochondrial membrane potential(P<0.05),as well as reduction of cellular oxygen consumption(P<0.05)and ATP production(P<0.05). Furthermore,the regulation of RIP140 on SIRT5 was dependent on the peroxisome proliferator-activated receptorα(PPARα)in cardiomyocytes.[Conclusion]RIP140 induces mitochondrial dysfunction and metabolic impairment through repression of SIRT5 in cardiomyocytes.
ABSTRACT
A predominant chrysene-degrading strain was isolated and screened from biological sludge sampled from a coking plant,which can use chrysene as sole carbon source for growth in the selective culture me-dium.The phylogenetic tree of the strain was produced on the basis of morphology observation by SEM,experimental results of physiology and biochemistry and analysis of 16S rDNA sequence.The strain was identified as Achromobacter xylosoxidans.The effect of initial concentration of chrysene solution,inoculat-ing dose and pH on degradation efficiencies was investigated.The results indicate that the degrading charac-teristics of the strain is fine.The optimal degrading conditions are:initial concentration of chrysene solution 40 mg/L,inoculating dose(V/V)10%,pH 7.0~7.5,respectively.Under the optimal conditions,the degrading efficiency can reach more than 80% after 5 days at 30?C.