Project description:Filamentous fungi are important factories in the production and secretion of homologous and heterologous lignocellulolytic enzymes, however the regulation of protein secretion in these organisms need to be further explored. In order to investigate this regulation, Aspergillus nidulans recombinant strains were analyzed by transcriptomics. We designed three A. nidulans recombinant strains producing the following heterologous proteins: alpha-arabinofuranosidase (AbfA), beta-glucosidase (BglC) and thermophilic mannanase (1542). The heterologous genes abfA and bglC were highly expressed, while the levels of 1542 mRNA were similar to the reference gene. An indirect relationship between mRNA and the levels of protein secretion was observed, suggesting that transcription is not a bottleneck in these systems. Based on the general analysis of RNA-seq of the recombinant strains, it was possible to observe a predominant up-regulation response. Moreover, biological processes related to metabolism, protein with binding function and cellular transport were overrepresented. We also observed the unconventional splicing of hacA for the recombinant A. nidulansAbfA and A. nidulans1542, indicating some level of unfolded protein response. The global analysis showed mild stress at 2 h induction of heterologous protein production, which was normalized after 8 h. Our results provide insights to understand how A. nidulans adapts to the overproduction of heterologous proteins.
2020-07-14 | GSE101522 | GEO
Project description:Transcriptomics profiling at norvancomycin producing strains
Project description:In this study we have employed metabolomics approaches to understand the metabolic effects of producing enhanced green fluorescent protein (eGFP) as a recombinant protein in Escherichia coli cells. This metabolic burden analysis was performed against a number of recombinant expression systems and control strains and included: (i) standard transcriptional recombinant expression control system BL21(DE3) with the expression plasmid pET-eGFP, (ii) the recently developed dual transcriptional–translational recombinant expression control strain BL21(IL3), with pET-eGFP, (iii) BL21(DE3) with an empty expression plasmid pET, (iv) BL21(IL3) with an empty expression plasmid, and (v) BL21(DE3) without an expression plasmid; all strains were cultured under various induction conditions. The growth profiles of all strains together with the results gathered by the analysis of the Fourier transform infrared (FT-IR) spectroscopy data, identified IPTG-dependent induction as the dominant factor hampering cellular growth and metabolism, which was in general agreement with the findings of GC-MS analysis of cell extracts and media samples. In addition, the exposure of host cells to the synthetic inducer ligand, pyrimido[4,5-d] pyrimidine-2,4-diamine (PPDA), of the orthogonal riboswitch containing expression system (BL21(IL3)) did not display any detrimental effects, and its detected levels in all the samples were at similar levels, emphasising the inability of the cells to metabolise PPDA. The overall results obtained in this study suggested that although the BL21(DE3)-EGFP and BL21(IL3)-EGFP strains produced comparable levels of recombinant eGFP, the presence of the orthogonal riboswitch seemed to be moderating the metabolic burden of eGFP production in the cells enabling higher biomass yield, whilst providing a greater level of control over protein expression.
Project description:The direct photosynthetic production of polyhydroxyalkanoate in cyanobacteria was improved by increasing carbon flux to biosynthetic pathway and introducing enzyme with higher activity. To understand the global transcriptional changes under photoautotrophic PHA biosynthesis conditions, RNA-seq analysis was performed. Transcriptomes of recombinant Synechocystis sp. with different PHA-producing potential (three strains, two biological replicates for each strain) were analyzed.
Project description:Although metabolic engineering approaches have benefited the development of industrial strains enormously, they are often only partially successful, such that additional rounds of modification are generally needed to ensure microbial strains meet all the requirements of a particular process. Systems biology approaches can aid in yeast design providing an integrated view of yeast physiology and helping to identify targets for modification. Among other phenotypes, the generation of wine yeasts that are able to produce wines with reduced ethanol concentrations has been the focus of extensive research. However, while producing low-alcohol wines, these strains generally produce off-flavour metabolites as metabolic by-products. We therefore used transcriptomics, proteomics and metabolomics to investigate the physiological changes of such an engineered low-ethanol wine strain during wine fermentation to determine possible strategies for by-product remediation. Integration of ‘omics data led to the identification of several processes, including reactions related to the pyruvate node and redox homeostasis, as significantly different compared to a non-engineered parent strain, with acetaldehyde and 2,4,5-trimethyl 1,3-dioxolane identified as the main off-flavour metabolites. Gene remediation strategies were applied to decrease the formation of these metabolites, while maintaining the ‘low-alcohol’ phenotype.
Project description:In this study we focus on two Saccharomyces cerevisiae (CEN. PK series) strains producing either insulin precursor or amylase and we compare the transcriptional regulation at different dilution rates, in particular with the objective to identify the relationship between cell metabolism and recombinant protein production. We found that anaerobic conditions showed high amount of amylase productions when comparing to aerobic conditions and the genome-scale transcriptional analysis suggested that genes related to the endoplasmic reticulum (ER), lipid synthesis and stress responses were generally up-regulated at anaerobic conditions. Moreover, we proposed a model for the electron transfer from ER to the final electron acceptor, fumarate under anaerobic conditions. Two Saccharomyces cerevisiae strains producing either insulin precursor or amylase were selected at different dilution rates in chemostat cultivation for RNA extraction and hybridization on Affymetrix microarrays. Biological triplicates were applied.
Project description:Using genetic engineering tools available for the model organism Aspergillus nidulans, we constructed two recombinant strains; one expressing the model polyketide Penicillium griseofulvum 6-methylsalicylic acid (6-MSA) polyketide synthase gene, and one expressing the 6-MSA gene and overexpressing the native phosphoketolase (phk) for increasing the pool of polyketide precursor levels. The physiology of the recombinant strains and a reference wild type were characterized on glucose, xylose, glycerol and ethanol medium in controlled bioreactors. Glucose was found to be the preferable carbon source for 6-MSA production and 6-MSA titers up to 455 mg/L were achieved. Our findings indicate that overexpression of phk does not directly improve 6-MSA production on glucose but if the lower glycolysis is lowered, it is possible to obtain quite high conversion yields of sugar to 6-MSA. Systems biology tools were employed for in-depth analysis of the metabolic processes. Transcriptome analysis of 6-MSA producing strains on glucose and xylose in the presence and absence of phk overexpression combined with flux and physiology data enabled us to propose a model of phk/6msas interaction describing two different responses influencing 6-MSA production.
Project description:Strains: non-producing refernece strain pXMJ19 (CR099 pXMJ19; Goldbeck et al., 2021) and Pediocin-producer pxMJ19 ped (CR099 pXMJ19 Ptac pedACDCg, Goldbeck et al., 2021) Pediocin-producing and non-producing strains of Corynebacterium glutamicum were compared in a whole genome microarray analysis setup in order to identify potential strain optimization targets
Project description:Using genetic engineering tools available for the model organism Aspergillus nidulans, we constructed two recombinant strains; one expressing the model polyketide Penicillium griseofulvum 6-methylsalicylic acid (6-MSA) polyketide synthase gene, and one expressing the 6-MSA gene and overexpressing the native phosphoketolase (phk) for increasing the pool of polyketide precursor levels. The physiology of the recombinant strains and a reference wild type were characterized on glucose, xylose, glycerol and ethanol medium in controlled bioreactors. Glucose was found to be the preferable carbon source for 6-MSA production and 6-MSA titers up to 455 mg/L were achieved. Our findings indicate that overexpression of phk does not directly improve 6-MSA production on glucose but if the lower glycolysis is lowered, it is possible to obtain quite high conversion yields of sugar to 6-MSA. Systems biology tools were employed for in-depth analysis of the metabolic processes. Transcriptome analysis of 6-MSA producing strains on glucose and xylose in the presence and absence of phk overexpression combined with flux and physiology data enabled us to propose a model of phk/6msas interaction describing two different responses influencing 6-MSA production. Four strains on two carbon sources
Project description:SAM is the principal methyl group donor in all living organisms, and has attracted much interest in clinical research. We improved SAM production in engineered P. pastoris strain GS115/DS56 by overexpression of the recombinant methionine adenosyltransferase (MAT) gene DS56, and further enhanced SAM prduction in G12-CBS by downregulation of the cystathionine β-synthase (CBS) gene CYS4 with a weak promoter G12. We performed the pairwise transcriptome comparisons between high-producing (HP) and low-producing (LP) strains, in order to understand the impact of SAM accumulation on the P. pastoris physiology and to identify genome-wide targets for further improving SAM production.