The high molecular weight (>1 MDa) of hyaluronic acid (HA) is important for its biological functions. The reported limiting factors for the production of HA with high molecular weight (MW) by microbial fermentation are the insufficient HA precursor pool and cell growth inhibition. To overcome these issues, the Xenopus laevis xhasA2 and xhasB genes encoding hyaluronan synthase 2 (xhasA2) and UDP-glucose dehydrogenase (xhasB), were expressed in Pichia pastoris widely used for production of heterologous proteins. In this study, expression vectors containing various combination cassettes of HA pathway genes including xhasA2 and xhasB from X. laevis as well as UDP-glucose pyrophosphorylase (hasC), UDP-N-acetylglucosamine pyrophosphorylase (hasD) and phosphoglucose isomerase (hasE) from P. pastoris were constructed and tested. First, HA pathway genes were overexpressed using pAO815 and pGAPZB vectors, resulting in the production of 1.2 MDa HA polymers. Second, in order to decrease hyaluronan synthase expression a strong AOX1 promoter in the xhasA2 gene was replaced by a weak AOX2 promoter which increased the mean MW of HA to 2.1 MDa. Finally, the MW of HA polymer was further increased to 2.5 MDa by low-temperature cultivation (26 °C) which reduced cell growth inhibition. The yield of HA production by the P. pastoris recombinant strains in 1L of fermentation culture was 0.8-1.7 g/L.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/j.jbiotec.2014.05.018 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Manipulating Dynamic Light-Driven Solid-Liquid Transition and Static Reversible Photochromism via Organic Cocrystal Strategy.
Angew Chem Int Ed Engl
January 2025
Henan University of Technology, School of Chemistry and Chemical Engineering, CHINA.
Developing of molecular crystalline materials with light-induced multiple dynamic deformation in space dimension and photochromism on time scales has attracted much attention for its potential applications in actuators, sensoring and information storage. Nevertheless, organic crystals capable of both photoinduced dynamic effects and static color change are rare, particularly for multi-component cocrystals system. In this study, we first report the construction of charge transfer co-crystals allows their light-induced solid-to-liquid transition and photochromic behaviors to be controlled by trans-stilbene (TSB) as an electron donor and 3,4,5,6-Tetrafluorophthalonitrile (TFP) as an electron acceptor.
View Article and Find Full Text PDFRole of the gut microbiome in psychological symptoms associated with inflammatory bowel diseases.
Semin Immunopathol
January 2025
Department of Medicine II, Medical Faculty Mannheim, University Medical Center Mannheim, Heidelberg University, Mannheim, Germany.
The brain-gut axis constitutes the basis for the bidirectional communication between the central nervous system and the gastrointestinal tract driven by neural, hormonal, metabolic, immunological, and microbial signals. Alterations in the gut microbiome composition as observed in inflammatory bowel diseases can modulate brain function and emerging empirical evidence has indicated that interactions among the brain-gut microbiome-axis seem to play a significant role in the pathogenesis of both inflammatory bowel diseases and psychiatric disorders and their comorbidity. Yet, the immunological and molecular mechanisms underlying the co-occurrence of inflammatory bowel diseases and psychological symptoms are still poorly understood.
View Article and Find Full Text PDFExposomics: a review of methodologies, applications, and future directions in molecular medicine.
EMBO Mol Med
January 2025
Department of Environmental Health, Harvard T. H. Chan School of Public Health, Boston, MA, 02115, USA.
The exposome is the measure of all the exposures of an individual in a lifetime and how those exposures relate to health. Exposomics is the emerging field of research to measure and study the totality of the exposome. Exposomics can assist with molecular medicine by furthering our understanding of how the exposome influences cellular and molecular processes such as gene expression, epigenetic modifications, metabolic pathways, and immune responses.
View Article and Find Full Text PDFA deep learning pipeline for three-dimensional brain-wide mapping of local neuronal ensembles in teravoxel light-sheet microscopy.
Nat Methods
January 2025
Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.
Teravoxel-scale, cellular-resolution images of cleared rodent brains acquired with light-sheet fluorescence microscopy have transformed the way we study the brain. Realizing the potential of this technology requires computational pipelines that generalize across experimental protocols and map neuronal activity at the laminar and subpopulation-specific levels, beyond atlas-defined regions. Here, we present artficial intelligence-based cartography of ensembles (ACE), an end-to-end pipeline that employs three-dimensional deep learning segmentation models and advanced cluster-wise statistical algorithms, to enable unbiased mapping of local neuronal activity and connectivity.
View Article and Find Full Text PDFA genome-wide atlas of human cell morphology.
Nat Methods
January 2025
Broad Institute of MIT and Harvard, Cambridge, MA, USA.
A key challenge of the modern genomics era is developing empirical data-driven representations of gene function. Here we present the first unbiased morphology-based genome-wide perturbation atlas in human cells, containing three genome-wide genotype-phenotype maps comprising CRISPR-Cas9-based knockouts of >20,000 genes in >30 million cells. Our optical pooled cell profiling platform (PERISCOPE) combines a destainable high-dimensional phenotyping panel (based on Cell Painting) with optical sequencing of molecular barcodes and a scalable open-source analysis pipeline to facilitate massively parallel screening of pooled perturbation libraries.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!