ABSTRACT
Objective To investigate the expression of circulating microRNA (miRNA) of rats with hypobaric hypoxia‐induced pulmonary hypertension (HPH) .Methods Commercial rat miRNA microarray was employed to detect and analyze the circulating miRNA profile in the serum samples of Sprague‐Dawley rats with hypobaric hypoxia‐induced HPH and controls .Furthermore ,differentially expressed candidate circulating miRNAs between HPH and control groups were validated by Real‐time quantitative PCR based on the case‐control study ,and receiver operating characteristic curve (ROC ) analysis was used to test the performance of four differentially expressed circulating miRNAs in discriminating HPH and control groups .Results Compared with those in the control group ,13 upregulated miRNAs and 10 downregulated miRNAs were identified in hypobaric hypoxia‐induced HPH rats by using miRNA microarray . And differentially expressed miR‐451 , miR‐505 , let‐7d and miR‐214 were validated by using RT‐PCR .ROC analysis showed that the area under the curve of miR‐451 ,miR‐505 and let‐7d was 0 .979 ,0 .938 and 0 .993 in discriminating HPH and control groups ,respectively .Conclusion The aberrant expression of circulating miR‐451 ,miR‐505 and let‐7d in serum may be correlated with the pathogenesis of HPH .
ABSTRACT
β-carotene has a wide range of application in food, pharmaceutical and cosmetic industries. For microbial production of β-carotene in Saccharomyces cerevisiae, the supply of geranylgeranyl diphosphate (GGPP) was firstly increased in S. cerevisiae BY4742 to obtain strain BY4742-T2 through over-expressing truncated 3-hydroxy-3-methylglutaryl-CoA reductase (tHMGR), which is the major rate-limiting enzyme in the mevalonate (MVA) pathway, and GGPP synthase (GGPS), which is a key enzyme in the diterpenoid synthetic pathway. The β-carotene synthetic genes of Pantoea agglomerans and Xanthophyllomyces dendrorhous were further integrated into strain BY4742-T2 for comparing β-carotene production. Over-expression of tHMGR and GGPS genes led to 26.0-fold increase of β-carotene production. In addition, genes from X. dendrorhous was more efficient than those from P. agglomerans for β-carotene production in S. cerevisiae. Strain BW02 was obtained which produced 1.56 mg/g (dry cell weight) β-carotene, which could be used further for constructing cell factories for β-carotene production.