41 research outputs found
Engineered Nanogel Particles Enhance the Photoautotrophic Biosynthesis of Polyhydroxyalkanoate in Marine Photosynthetic Bacteria
Improving polyhydroxyalkanoate (PHA, a biodegradable plastic) production under photoautotrophic cultivation is challenging for sustainable bioproduction. In this study, we demonstrated the use of engineered nanogel particles to enhance PHA accumulation in the marine photosynthetic bacterium Rhodovulum sulfidophilum under photoautotrophic culture. We screened the effect of 13 engineered nanogel particles on the cell growth and PHA accumulation of R. sulfidophilum. The addition of anionic nanogel particles significantly enhanced PHA accumulation in R. sulfidophilum up to 157-fold compared to that without nanogel particles. By performing ÂčÂłC tracer experiments and gas chromatographyâmass spectrometry analysis, we confirmed that HCOââ» was assimilated throughout the central carbon metabolism and that the accumulated PHA was indeed incorporated from HCOââ». Our results indicate successful PHA production with the supplementation of engineered nanogel particles under photoautotrophic cultivation in R. sulfidophilum. Furthermore, the strategy of using engineered nanoparticles demonstrated in this study may be applicable to other microbial cell factories to produce other commodity metabolites
Effects of plasma rotating electrode process parameters on the particle size distribution and microstructure of Ti-6Al-4âŻV alloy powder
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Efficient 3âHydroxybutyrate Production by Quiescent Escherichia coli Microbial Cell Factories is Facilitated by IndoleâInduced Proteomic and Metabolomic Changes
The authors show that quiescent (QâCell) Escherichia coli cultures can maintain metabolic activity in the absence of growth for up to 24âh, leading to four times greater specific productivity of a model metabolite, 3âhydroxybutyrate (3HB), than a control. Qâcells can be created by using the proton ionophore indole to halt cell division of an hns mutant strain. This uncouples metabolism from cell growth and allows for more efficient use of carbon feedstocks because less metabolic effort is diverted to surplus biomass production. However, the reason for the increased productivity of cells in the quiescent state was previously unknown. In this study, proteome expression patterns between wildâtype and Qâcell cultures show that Qâcells overexpress stress response proteins, which prime them to tolerate the metabolic imbalances incurred through indole addition. Metabolomic data reveal the accumulation of acetylâcoenzyme A and phosphoenolpyruvate: excellent starting points for highâvalue chemical production. We demonstrate the exploitation of these accumulated metabolites by engineering a simple pathway for 3HB production from acetylâcoenzyme A. Quiescent cultures produced half the cell biomass of control cultures lacking indole, but were still able to produce 39.4âgâLâ1 of 3HB compared to 18.6âgâLâ1 in the control. Qâcells therefore have great potential as a platform technology for the efficient production of a wide range of commodity and high value chemicals
Acetylation of C/EBP alpha inhibits its granulopoietic function
CCAAT/enhancer-binding protein alpha (C/EBP alpha) is an essential transcription factor for myeloid lineage commitment. Here we demonstrate that acetylation of C/EBP alpha at lysine residues K298 and K302, mediated at least in part by general control non-derepressible 5 (GCN5), impairs C/EBP alpha DNA-binding ability and modulates C/EBP alpha transcriptional activity. Acetylated C/EBP alpha is enriched in human myeloid leukaemia cell lines and acute myeloid leukaemia (AML) samples, and downregulated upon granulocyte-colony stimulating factor (G-CSF)-mediated granulocytic differentiation of 32Dcl3 cells. C/EBP alpha mutants that mimic acetylation failed to induce granulocytic differentiation in C/EBP alpha-dependent assays, in both cell lines and in primary hematopoietic cells. Our data uncover GCN5 as a negative regulator of C/EBP alpha and demonstrate the importance of C/EBP alpha acetylation in myeloid differentiation
Lysine acetyltransferase Tip60 is required for hematopoietic stem cell maintenance.
Hematopoietic stem cells (HSCs) have the potential to replenish the blood system for the lifetime of the organism. Their 2 defining properties, self-renewal and differentiation, are tightly regulated by the epigenetic machineries. Using conditional gene-knockout models, we demonstrated a critical requirement of lysine acetyltransferase 5 (Kat5, also known as Tip60) for murine HSC maintenance in both the embryonic and adult stages, which depends on its acetyltransferase activity. Genome-wide chromatin and transcriptome profiling in murine hematopoietic stem and progenitor cells revealed that Tip60 colocalizes with c-Myc and that Tip60 deletion suppress the expression of Myc target genes, which are associated with critical biological processes for HSC maintenance, cell cycling, and DNA repair. Notably, acetylated H2A.Z (acH2A.Z) was enriched at the Tip60-bound active chromatin, and Tip60 deletion induced a robust reduction in the acH2A.Z/H2A.Z ratio. These results uncover a critical epigenetic regulatory layer for HSC maintenance, at least in part through Tip60-dependent H2A.Z acetylation to activate Myc target genes.Cancer Research UK, Wellcome Trust, National Institutes of Health, Singapore state fundin
The Ganymede Laser Altimeter (GALA) for the Jupiter Icy Moons Explorer (JUICE): Mission, science, and instrumentation of its receiver modules
The Jupiter Icy Moons Explorer (JUICE) is a science mission led by the European Space Agency, being developed for launch in 2023. The Ganymede Laser Altimeter (GALA) is an instrument onboard JUICE, whose main scientific goals are to understand ice tectonics based on topographic data, the subsurface structure by measuring tidal response, and small-scale roughness and albedo of the surface. In addition, from the perspective of astrobiology, it is imperative to study the subsurface ocean scientifically. The development of GALA has proceeded through an international collaboration between Germany (the lead), Japan, Switzerland, and Spain. Within this framework, the Japanese team (GALA-J) is responsible for developing three receiver modules: the Backend Optics (BEO), the Focal Plane Assembly (FPA), and the Analog Electronics Module (AEM). Like the German team, GALA-J also developed software to simulate the performance of the entire GALA system (performance model). In July 2020, the Proto-Flight Models of BEO, FPA, and AEM were delivered from Japan to Germany. This paper presents an overview of JUICE/GALA and its scientific objectives and describes the instrumentation, mainly focusing on Japanâs contribution