Lipid Catabolic Process Research Articles

Transcriptome analysis reveals differential gene expression in intramuscular adipose tissues of Jinhua and Landrace pigs.

Meat is a rich source of protein, fatty acids and carbohydrates for human needs. In addition to necessary nutrients, high fat contents in pork increase the tenderness and juiciness of the meat, featuring diverse application in various dishes. This study investigated the transcriptomic profiles of intramuscular adipose tissues in Jinhua and Landrace pigs by employing advanced RNA sequencing. Results showed significant interesting to note that there were significant differences in the expression of genes. 1,632 genes showed significant differential expression, 837 genes were up-regulated and 195 genes were down-regulated. Variations in genes responsible for cell aggregation, extracellular matrix formation, cellular lipid catabolic process, and fatty acid binding strongly supported that both pig breeds feature variable fat and muscle metabolism. Certain differentially expressed genes are included in the pathway of mitogen-activated protein kinase signaling pathway, Ras signaling pathway and insulin pathway. Results from real-time quantitative polymerase chain reaction also validated the differential expression of 17 mRNAs between meats of the two pig breeds. Overall, these findings reveal significant differences in fat and protein metabolism of intramuscular adipose tissues of two pig breeds at the transcriptomic level and suggest diversification at the genetic level between breeds of the same species.

A Global Transcriptome Analysis Reveals Molecular Hallmarks of Neural Stem Cell Death, Survival, and Differentiation in Response to Partial FGF-2 and EGF Deprivation

Neurosphere cell culture is a commonly used model to study the properties and potential applications of neural stem cells (NSCs). However, standard protocols to culture NSCs have yet to be established, and the mechanisms underlying NSC survival and maintenance of their undifferentiated state, in response to the growth factors FGF-2 and EGF are not fully understood. Using cultures of embryonic and adult olfactory bulb stem cells (eOBSCs and aOBSCs), we analyzed the consequences of FGF-2 and EGF addition at different intervals on proliferation, cell cycle progression, cell death and differentiation, as well as on global gene expression. As opposed to cultures supplemented daily, addition of FGF-2 and EGF every 4 days significantly reduced the neurosphere volume and the total number of cells in the spheres, mainly due to increased cell death. Moreover, partial FGF-2 and EGF deprivation produced an increase in OBSC differentiation during the proliferative phase. These changes were more evident in aOBSC than eOBSC cultures. Remarkably, these effects were accompanied by a significant upregulation in the expression of endogenous Fgf-2 and genes involved in cell death and survival (Cryab), lipid catabolic processes (Pla2g7), cell adhesion (Dscaml1), cell differentiation (Dscaml1, Gpr17, S100b, Ndrg2) and signal transduction (Gpr17, Ndrg2). These findings support that a daily supply of FGF-2 and EGF is critical to maintain the viability and the undifferentiated state of NSCs in culture, and they reveal novel molecular hallmarks of NSC death, survival and the initiation of differentiation.

MEMBRANE STRUCTURAL LIPID CHANGES IN FRESH-CUT CARROTS: REVISITING THE "WOUNDING AND AGING" PHENOMENON

Virtually no quantitative data exist for membrane lipid metabolism of fresh-cut (wound-stressed) vegetables and fruits, despite the inevitable consequences of wounding. One such result is the rupture of cell membranes and activation of membrane lipid catabolic processes. We have evaluated changes in membrane sterols and glycerolipids in shredded carrots, a popular fresh-cut commodity. 'Apache' and 'Caropak' carrots were shredded and stored under conditions similar to those used in retail markets (10°C and 95% RH). Between 0 and 10 days of storage, membrane lipid concentrations in the shredded tissue were determined using HPLC/evaporative light scattering detection. Total phospholipid and acylated sterol glycoside concentrations increase by as much as 31% and 135%, respectively, following 10 days of storage. These increases are indicative of membrane restructuring (repair) processes, are accentuated by Ca 2+ pretreatment, and appear to be cultivar-dependent. During storage, Ca 2+ pretreatment also delays onset of increases in the ratios of free sterols to phospholipids and of free stigmasterol to free sitosterol (both senescence-driven processes); and as expected, Ca 2+ pretreatment reduces cell permeability. However, Ca 2+ pretreatment does not curb the rate of accumulation of phosphatidic acid, a membrane degradation product. Coexistence of membrane degradation and repair processes appears to be a characteristic feature of wounding and long-term storage of carrots. Further, Ca 2+ pretreatment may prove to be a valuable approach for maintaining quality of fresh-cut carrots and possibly other fresh-cut products, owing to its stabilising influence on cell membrane systems.