A two-dimensional electrophoresis and mass spectrometry protein analysis of the antibiotic producer Nonomuraea sp. ATCC 39727 in different growth conditions

Enhancing 2-Ketogluconate Production of Pseudomonas plecoglossicida JUIM01 by Maintaining the Carbon Catabolite Repression of 2-Ketogluconate Metabolism

2-Ketogluconate (2KGA) is an organic acid that is important for pharmaceutical, cosmetic, and environmental applications. Pseudomonas plecoglossicida JUIM01 strain is an important industrial 2KGA producer in China. In this paper, we found that P. plecoglossicida JUIM01 could convert glucose to 2KGA extracellularly, and the formed 2KGA was subsequently consumed after glucose was exhausted during the fermentation process. Experiments of glucose and 2KGA supplementation during fermentation process revealed that, only when glucose was exhausted, the strain started to consume the product 2KGA. Then, the mechanism of this phenomenon was investigated at transcription and protein levels, and the results indicated that P. plecoglossicida JUIM01 possesses carbon catabolite repression of 2KGA metabolism by glucose. Next, increasing the supply of glucose could attenuate 2KGA consumption and enhance the 2KGA yield from glucose. Finally, fed-batch fermentation of P. plecoglossicida JUIM01 resulted in 205.67 g/L of 2KGA with a productivity of 6.86 g/L/h and yield of 0.953 g/g glucose. These results can provide references for the industrial fermentation production of 2KGA and other fermentation products.

Proteomic studies on anti-tumor agent ansamitocin P-3 producer Actinosynnema pretiosum in response to ammonium and isobutanol

Our previous work showed that the biosynthesis of ansamitocin P-3 (AP-3), an anti-tumor agent, by Actinosynnema pretiosum was depressed by ammonium but enhanced by isobutanol in the medium. Here we show proteomics analyses on A. pretiosum in different fermentation conditions with and without ammonium or isobutanol using two-dimensional electrophoresis (2-DE), matrix-assisted laser desorption/ionization, and linear ion trap quadrupole mass spectrometry. Pairwise comparison of repetitive 2-DE maps was performed to find differentially expressed spots, and eight proteins were identified as functionally annotated ones. Among these proteins, D-3-phosphoglycerate dehydrogenase (PGDH) and glyceraldehyde 3-phosphate dehydrogenase showed statistically significant up-regulation in ammonium vs. basic or isobutanol medium, while fatty acid synthetase, histidine-tRNA ligase, transposase, molecular chaperone GroEL, SAM-dependent methyltransferase, and Crp/Fnr family transcriptional regulator were overexpressed in ammonium vs. basic medium. Based on the 2-DE data, exogenous L-serine which could inhibit the PGDH activity was added to the cultures with isobutanol, and a lower AP-3 production was confirmed under 2.5 mM serine addition (24 or 48 h).

The genus Nonomuraea: A review of a rare actinomycete taxon for novel metabolites

The genus Nonomuraea is a rare actinomycete taxon with a long taxonomic history, while its generic description was recently emended. The genus is less known among the rare actinomycete genera as its taxonomic position was revised several times. It can be found in diverse ecological niches, while most of its member species were isolated from soil samples. However, new trends to discover the genus in other habitats are increasing. Generic abundance of the genus was found to be dependent on geographical changes. Novel sources together with selective and invented isolation techniques might increase a chance to explore the genus and its novel candidates. Interestingly, some of its members have been revealed as a valuable source of novel metabolites for medical and industrial purposes. Broad-range of potent bioactive compounds including antimicrobial, anticancer, and antipsychotic substances, broad-spectrum antibiotics and biocatalysts can be synthesized by the genus. In order to investigate biosynthetic pathways of the bioactive compounds and self-resistant mechanisms to these compounds, the links from genes to metabolites have yet been needed for further discovery and biotechnological development of the genus Nonomuraea.