Ocean University of China

About: Ocean University of China is a education organization based out in Qingdao, China. It is known for research contribution in the topics: Population & Sea surface temperature. The organization has 27604 authors who have published 27886 publications receiving 440181 citations. The organization is also known as: Zhōngguó Hǎiyáng Dàxué & OUC.

Trimethylamine-N-oxide (TMAO)-induced atherosclerosis is associated with bile acid metabolism

Abstract: Recently, trimethylamine-N-oxide (TMAO) plasma levels have been proved to be associated with atherosclerosis development. Among the targets aimed to ameliorating atherosclerotic lesions, inducing bile acid synthesis to eliminate excess cholesterol in body is an effective way. Individual bile acid as endogenous ligands for the nuclear receptor has differential effects on regulating bile acid metabolism. It is unclear whether bile acid profiles are mechanistically linked to TMAO-induced development of atherosclerosis. Male apoE−/− mice were fed with control diet containing 0.3% TMAO for 8 weeks. Aortic lesion development and serum lipid profiles were determined. Bile acid profiles in bile, liver and serum were measured by liquid chromatographic separation and mass spectrometric detection (LC-MS). Real-time PCRs were performed to analyze mRNA expression of genes related to hepatic bile acid metabolism. The total plaque areas in the aortas strongly increased 2-fold (P < 0.001) in TMAO administration mice. The levels of triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c) in TMAO group were also significantly increased by 25.5% (P = 0.044), 31.2% (P = 0.006), 28.3% (P = 0.032), respectively. TMAO notably changed bile acid profiles, especially in serum, the most prominent inductions were tauromuricholic acid (TMCA), deoxycholic acid (DCA) and cholic acid (CA). Mechanically, TMAO inhibited hepatic bile acid synthesis by specifically repressing the classical bile acid synthesis pathway, which might be mediated by activation of small heterodimer partner (SHP) and farnesoid X receptor (FXR). These findings suggested that TMAO accelerated aortic lesion formation in apoE−/− mice by altering bile acid profiles, further activating nuclear receptor FXR and SHP to inhibit bile acid synthesis by reducing Cyp7a1 expression.

High-Resolution Linkage and Quantitative Trait Locus Mapping Aided by Genome Survey Sequencing: Building Up An Integrative Genomic Framework for a Bivalve Mollusc

Abstract: Genetic linkage maps are indispensable tools in genetic and genomic studies. Recent development of genotyping-by-sequencing (GBS) methods holds great promise for constructing high-resolution linkage maps in organisms lacking extensive genomic resources. In the present study, linkage mapping was conducted for a bivalve mollusc (Chlamys farreri) using a newly developed GBS method—2b-restriction site-associated DNA (2b-RAD). Genome survey sequencing was performed to generate a preliminary reference genome that was utilized to facilitate linkage and quantitative trait locus (QTL) mapping in C. farreri. A high-resolution linkage map was constructed with a marker density (3806) that has, to our knowledge, never been achieved in any other molluscs. The linkage map covered nearly the whole genome (99.5%) with a resolution of 0.41 cM. QTL mapping and association analysis congruously revealed two growth-related QTLs and one potential sex-determination region. An important candidate QTL gene named PROP1, which functions in the regulation of growth hormone production in vertebrates, was identified from the growth-related QTL region detected on the linkage group LG3. We demonstrate that this linkage map can serve as an important platform for improving genome assembly and unifying multiple genomic resources. Our study, therefore, exemplifies how to build up an integrative genomic framework in a non-model organism.