Pretreatment of lignocellulosic biomass produces growth inhibitory substances such as furfural which is toxic to microorganisms. Acinetobacter baylyi ADP1 cannot use furfural as a carbon source, instead it biotransforms this compound into difurfuryl ether using the reduced nicotinamide adenine dinucleotide (NADH)-dependent dehydrogenases AreB and FrmA during aerobic acetate catabolism. However, NADH consumption for furfural biotransformation compromises aerobic growth of A.
View Article and Find Full Text PDFDecoupling cell formation from recombinant protein synthesis is a potent strategy to intensify bioprocesses. Escherichia coli strains with mutations in the glucose uptake components lack catabolite repression, display low growth rate, no overflow metabolism, and high recombinant protein yields. Fast growth rates were promoted by the simultaneous consumption of glucose and glycerol, and this was followed by a phase of slow growth, when only glucose remained in the medium.
View Article and Find Full Text PDFThe demand of plasmid DNA (pDNA) as a key element for gene therapy products, as well as mRNA and DNA vaccines, is increasing together with the need for more efficient production processes. An engineered strain lacking the phosphotransferase system and the pyruvate kinase A gene has been shown to produce more pDNA than its parental strain. With the aim of improving pDNA production in the engineered strain, several strategies to increase the flux to the pentose phosphate pathway (PPP) were evaluated.
View Article and Find Full Text PDFIndustrial cultures are hindered by the physiological complexity of the host and the limited mass transfer capacity of conventional bioreactors. In this study, a minimal cell approach was combined with genetic devices to overcome such issues. A flavin mononucleotide-based fluorescent protein (FbFP) was expressed in a proteome-reduced Escherichia coli (PR).
View Article and Find Full Text PDFPlasmid DNA manufacture is an essential step to produce gene therapy agents and next-generation vaccines. However, little attention has been paid toward developing alternative replicons that can be coupled with large-scale production conditions. Our results demonstrate that the miniR1 replicon can be efficiently induced by oxygen limitation when a copy of the regulatory protein RepA under control of a microaerobic promoter is used.
View Article and Find Full Text PDFBackground: Fed-batch mode is the standard culture technology for industrial bioprocesses. Nevertheless, most of the early-stage cell and process development is carried out in batch cultures, which can bias the initial selection of expression systems. Cell engineering can provide an alternative to fed-batch cultures for high-throughput screening and host selection.
View Article and Find Full Text PDFFreezing stress is a critical environmental factor affecting survival, distribution, and evolution of plants. Although there is evidence that nitrogen (N) affects frost tolerance of juvenile conifers, the magnitude and direction of such effect can diverge among species. The influence of the N source on frost tolerance has been barely studied.
View Article and Find Full Text PDFObjectives: To determine furfural biotransformation capabilities of Acinetobacter baylyi ADP1 and Acinetobacter schindleri ACE.
Results: Acinetobacter baylyi ADP1 and A. schindleri ACE could not use furfural as sole carbon source but when acetate was used as substrate, ADP1 and ACE biotransformed 1 g furfural/l in 5 and 9 h, respectively.
The design of optimal cell factories requires engineering resource allocation for maximizing product synthesis. A recently developed method to maximize the saving in cell resources released 0.5% of the proteome of by deleting only three transcription factors.
View Article and Find Full Text PDFJ Microbiol Biotechnol
October 2020
The aerobic growth and metabolic performance of strains BL21 and W3110 were studied when the hemoglobin (VHb) was constitutively expressed in the chromosome. When VHb was expressed, acetate production decreased in both strains and was nearly eliminated in BL21. Transcriptional levels of the glyoxylate shunt genes decreased in both strains when VHb was expressed.
View Article and Find Full Text PDFDrought is a limiting factor to forest regeneration and restoration, which is likely to increase in intensity and duration under future climates. Nitrogen (N) nutrition is related to drought-resistance mechanisms in trees. However, the influence of chemical N form (inorganic and organic N) on physiological traits related to drought resistance has been sparsely studied in conifer seedlings.
View Article and Find Full Text PDFAcinetobacter bacteria preferentially use gluconeogenic substrates instead of hexoses or pentoses. Accordingly, Acinetobacter schindleri ACE reaches a high growth rate on acetate but is unable to grow on glucose, xylose or arabinose. In this work, we compared the physiology of A.
View Article and Find Full Text PDFA pUC-derived replicon inducible by oxygen limitation was designed and tested in fed-batch cultures of Escherichia coli. It included the addition of a second inducible copy of rnaII, the positive replication control element. The rnaII gene was expressed from P and cloned into pUC18 to test the hypothesis that the ratio of the positive control molecule RNAII to the negative control element, RNAI, was the determinant of plasmid copy number per chromosome (PCN).
View Article and Find Full Text PDFAcinetobacter baylyi ADP1 is a microorganism with the potential to produce storage lipids. Here, a systematic study was carried out to evaluate growth performance and accumulation of wax esters and triacylglycerols using glycerol, xylose, glucose, acetate, ethanol, and pyruvate as carbon sources. High specific growth rates (μ) were found in gluconeogenic carbon sources (ethanol, acetate, and pyruvate: 0.
View Article and Find Full Text PDFBioprocess Biosyst Eng
September 2019
Escherichia coli strains W3110 and BL21 were engineered for the production of plasmid DNA (pDNA) under aerobic and transitions to microaerobic conditions. The gene coding for recombinase A (recA) was deleted in both strains. In addition, the Vitreoscilla hemoglobin (VHb) gene (vgb) was chromosomally inserted and constitutively expressed in each E.
View Article and Find Full Text PDFA synthetic plasmid consisting of the minimal elements for replication control of the R1 replicon and kanamycin resistance marker, which was named pminiR1, was developed. pminiR1 production was tested at 30 °C under aerobic and microaerobic conditions in Escherichia coli W3110 recA (W1). The plasmid DNA yields from biomass (Y) were only 0.
View Article and Find Full Text PDFHispanic women living on the US-Mexico border have had higher cesarean delivery rates than other Hispanic women in the US. Using birth certificate and other data, we compared cesarean rates among Hispanic women living in US border counties with rates among other Hispanic women in border states during 2015. Using linear regression, we also determined which medical, hospital, and sociodemographic characteristics accounted for intercounty variations in rates.
View Article and Find Full Text PDFBackground: Cesarean delivery occurs in one in three US births and poses risks for mothers and infants. Hispanic cesarean rates were higher than non-Hispanic white rates in the US in 2016. In 2009, cesarean rates among Hispanics on the US-Mexico border exceeded rates among US Hispanics.
View Article and Find Full Text PDFBackground: A-kinase anchor protein 4 (AKAP4) and its precursor pro-AKAP4 are two major proteins in spermatozoa of rodents and mammals. Although researchers have characterized the AKAP4 expression in various species, the protein's expression in humans has not been described in detail.
Objectives: The objective of this study was to characterize human pro-AKAP4 more precisely (notably the definition of its localization and expression levels in human spermatozoa and testes).
A lower number of metaphase II oocytes eligible for vitrification after controlled stimulation in cancer patients has recently been reported, suggesting that cancer may impair the dynamics and quality of follicular growth. In this prospective, non-interventional study, the pattern of follicular growth and oocyte cohort after ovarian stimulation in cancer patients was analysed. Ninety cancer patients, recruited before starting chemotherapy, were compared with 180 time- and age-matched healthy controls undergoing intracytoplasmic sperm injection.
View Article and Find Full Text PDFOxygen-responsive promoters can be useful for synthetic biology applications, however, information on their characteristics is still limited. Here, we characterized a group of heterologous microaerobic globin promoters in . Globin promoters from , , , , and were used to express the FMN-binding fluorescent protein (FbFP), which is a non-oxygen dependent marker.
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