6 research outputs found
A tailored series of engineered yeasts for the cell-dependent treatment of inflammatory bowel disease by rational butyrate supplementation
ABSTRACTIntestinal microbiota dysbiosis and metabolic disruption are considered essential characteristics in inflammatory bowel disorders (IBD). Reasonable butyrate supplementation can help patients regulate intestinal flora structure and promote mucosal repair. Here, to restore microbiota homeostasis and butyrate levels in the patient’s intestines, we modified the genome of Saccharomyces cerevisiae to produce butyrate. We precisely regulated the relevant metabolic pathways to enable the yeast to produce sufficient butyrate in the intestine with uneven oxygen distribution. A series of engineered strains with different butyrate synthesis abilities was constructed to meet the needs of different patients, and the strongest can reach 1.8 g/L title of butyrate. Next, this series of strains was used to co-cultivate with gut microbiota collected from patients with mild-to-moderate ulcerative colitis. After receiving treatment with engineered strains, the gut microbiota and the butyrate content have been regulated to varying degrees depending on the synthetic ability of the strain. The abundance of probiotics such as Bifidobacterium and Lactobacillus increased, while the abundance of harmful bacteria like Candidatus Bacilloplasma decreased. Meanwhile, the series of butyrate-producing yeast significantly improved trinitrobenzene sulfonic acid (TNBS)-induced colitis in mice by restoring butyrate content. Among the series of engineered yeasts, the strain with the second-highest butyrate synthesis ability showed the most significant regulatory and the best therapeutic effect on the gut microbiota from IBD patients and the colitis mouse model. This study confirmed the existence of a therapeutic window for IBD treatment by supplementing butyrate, and it is necessary to restore butyrate levels according to the actual situation of patients to restore intestinal flora
High-Level Production of Hydroxytyrosol in Engineered Saccharomyces cerevisiae
Hydroxytyrosol (HT) is a valuable aromatic compound with
numerous
applications. Herein, we enabled the efficient and scalable de novo HT production in engineered Saccharomyces
cerevisiae (S. cerevisiae) from glucose. Starting from a tyrosol-overproducing strain, six
HpaB/HpaC combinations were investigated, and the best catalytic performance
was acquired with HpaB from Pseudomonas aeruginosa (PaHpaB) and HpaC from Escherichia
coli (EcHpaC), resulting in 425.7
mg/L HT in shake flasks. Next, weakening the tryptophan biosynthetic
pathway through downregulating the expression of TRP2 (encoding anthranilate synthase) further improved the HT titer by
27.2% compared to the base strain. Moreover, the cytosolic NADH supply
was improved through introducing the feedback-resistant mutant of
the TyrA (the NAD+-dependent chorismate mutase/prephenate
dehydrogenase, TyrA*) from E. coli,
which further increased the HT titer by 36.9% compared to the base
strain. The best performing strain was obtained by optimizing the
biosynthesis of HT in S. cerevisiae through a screening for an effective HpaB/HpaC combination, biosynthetic
flux rewiring, and cofactor engineering, which enabled the titer of
HT reaching 1120.0 mg/L in the shake flask. Finally, the engineered
strain produced 6.97 g/L of HT by fed-batch fermentation, which represents
the highest titer for de novo HT biosynthesis in
microorganisms reported to date
High-Level Production of Hydroxytyrosol in Engineered Saccharomyces cerevisiae
Hydroxytyrosol (HT) is a valuable aromatic compound with
numerous
applications. Herein, we enabled the efficient and scalable de novo HT production in engineered Saccharomyces
cerevisiae (S. cerevisiae) from glucose. Starting from a tyrosol-overproducing strain, six
HpaB/HpaC combinations were investigated, and the best catalytic performance
was acquired with HpaB from Pseudomonas aeruginosa (PaHpaB) and HpaC from Escherichia
coli (EcHpaC), resulting in 425.7
mg/L HT in shake flasks. Next, weakening the tryptophan biosynthetic
pathway through downregulating the expression of TRP2 (encoding anthranilate synthase) further improved the HT titer by
27.2% compared to the base strain. Moreover, the cytosolic NADH supply
was improved through introducing the feedback-resistant mutant of
the TyrA (the NAD+-dependent chorismate mutase/prephenate
dehydrogenase, TyrA*) from E. coli,
which further increased the HT titer by 36.9% compared to the base
strain. The best performing strain was obtained by optimizing the
biosynthesis of HT in S. cerevisiae through a screening for an effective HpaB/HpaC combination, biosynthetic
flux rewiring, and cofactor engineering, which enabled the titer of
HT reaching 1120.0 mg/L in the shake flask. Finally, the engineered
strain produced 6.97 g/L of HT by fed-batch fermentation, which represents
the highest titer for de novo HT biosynthesis in
microorganisms reported to date
Improving bgl1 gene expression in Saccharomyces cerevisiae through meiosis in an isogenic triploid
ET White Paper: To Find the First Earth 2.0
We propose to develop a wide-field and ultra-high-precision photometric
survey mission, temporarily named "Earth 2.0 (ET)". This mission is designed to
measure, for the first time, the occurrence rate and the orbital distributions
of Earth-sized planets. ET consists of seven 30cm telescopes, to be launched to
the Earth-Sun's L2 point. Six of these are transit telescopes with a field of
view of 500 square degrees. Staring in the direction that encompasses the
original Kepler field for four continuous years, this monitoring will return
tens of thousands of transiting planets, including the elusive Earth twins
orbiting solar-type stars. The seventh telescope is a 30cm microlensing
telescope that will monitor an area of 4 square degrees toward the galactic
bulge. This, combined with simultaneous ground-based KMTNet observations, will
measure masses for hundreds of long-period and free-floating planets. Together,
the transit and the microlensing telescopes will revolutionize our
understandings of terrestrial planets across a large swath of orbital distances
and free space. In addition, the survey data will also facilitate studies in
the fields of asteroseismology, Galactic archeology, time-domain sciences, and
black holes in binaries.Comment: 116 pages,79 figure