Heterologous expression of nrps33, a nonribosomal peptide synthetase gene, from Paecilomyces cinnamomeus BCC 9616 in Saccharomyces cerevisiae unexpectedly resulted in the accumulation of anthranilic acid, an intermediate in tryptophan biosynthesis. Based on transcriptomic and real-time quantitative polymerase chain reaction (RT-qPCR) results, expression of nrps33 affected the transcription of tryptophan biosynthesis genes especially TRP1 which is also the selectable auxotrophic marker for the expression vector used in this work. The product of nrps33 could inhibit the activity of Trp4 involved in the conversion of anthranilate to N-(5'-phosphoribosyl)anthranilate and therefore caused the accumulation of anthranilic acid. This accumulation could in turn result in down-regulation of downstream tryptophan biosynthesis genes. Anthranilic acid is typically produced by chemical synthesis and has been used as a substrate for synthesising bioactive compounds including commercial drugs; our results could provide a new biological platform for production of this compound.
Saccharomyces cerevisiae , Tryptophan , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae/metabolism , Tryptophan/metabolism , Peptide Synthases/genetics , Peptide Synthases/metabolism , ortho-Aminobenzoates/pharmacology , ortho-Aminobenzoates/metabolism
Dictyostelium intermedium is a member of dictyostelids, the unicellular eukaryotes with a unique life cycle, including a social cycle. Despite the high diversity of dictyostelids, only five species' complete mitochondrial genome sequences were reported. This study aimed to add the D. intermedium mitochondrial genome sequence to the list. The size of this genome is 58,627 bp, with 73.99% A/T, containing 62 genes located on one strand: 41 protein-coding genes, three ribosomal RNA genes, and 18 transfer RNA genes. The 41 protein-coding genes comprised 18 oxidative phosphorylation-related, 16 ribosomal, and seven hypothetical protein-coding genes. The cox1/2 and rnl gene contained introns, similar to other species of Dictyostelium. The phylogenetic tree built based on 34 protein sequences supported the monophyletic clade of Dictyostelium and the dictyostelids' ancestor's position between the two dictyostelids orders: Dictyosteliales and Acytosteliales.
