miRTarBase 2020: updates to the experimentally validated microRNA-target interaction database.

MicroRNAs (miRNAs) are small non-coding RNAs (typically consisting of 18-25 nucleotides) that negatively control expression of target genes at the post-transcriptional level. Owing to the biological significance of miRNAs, miRTarBase was developed to provide comprehensive information on experimentally validated miRNA-target interactions (MTIs). To date, the database has accumulated >13,404 validated MTIs from 11,021 articles from manual curations. In this update, a text-mining system was incorporated to enhance the recognition of MTI-related articles by adopting a scoring system. In addition, a variety of biological databases were integrated to provide information on the regulatory network of miRNAs and its expression in blood. Not only targets of miRNAs but also regulators of miRNAs are provided to users for investigating the up- and downstream regulations of miRNAs. Moreover, the number of MTIs with high-throughput experimental evidence increased remarkably (validated by CLIP-seq technology). In conclusion, these improvements promote the miRTarBase as one of the most comprehensively annotated and experimentally validated miRNA-target interaction databases. The updated version of miRTarBase is now available at http://miRTarBase.cuhk.edu.cn/.

Medium optimization for phenazine-1-carboxylic acid production by a gacA qscR double mutant of Pseudomonas sp. M18 using response surface methodology.

Statistics based experimental designs were applied to optimize the culture medium components for enhancing phenazine-1-carboxylic acid (PCA) production by Pseudomonas sp. strain M18GQ, a gacA qscR double mutant of Pseudomonas sp. strain M18. The medium components, including soybean meal, glucose and corn steep liquor, had significant effects on PCA production based on a 2(5-1) fractional factorial design. The concentrations of these three significant factors were subsequently optimized using a central composite design. An optimum concentration of soybean meal 73.3g/L, corn steep liquor 18.1g/L, glucose 17.9g/L, and ethanol 18.0ml/L was obtained by response surface analysis. The predicted maximum PCA yield was as high as 4011.5mg/L, and was confirmed by validation experiments. The double mutant M18GQ produced 4032.2mg/L PCA, which was almost 2 to 3.3-fold that produced by either single mutant M18G and M18Q. The achieved production level is economically useful for industrial application.