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Metabolic engineering

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https://www.readbyqxmd.com/read/28922845/pot1-mediated-%C3%AE-integration-strategy-for-high-copy-stable-expression-of-heterologous-proteins-in-saccharomyces-cerevisiae
#1
Xiaofei Song, Quanli Liu, Jiwei Mao, Yuzhen Wu, Yuanzi Li, Kai Gao, Xiuming Zhang, Yanling Bai, Haijin Xu, Mingqiang Qiao
In biotechnological industry, increased expression cassette stability and copy number serve as important means of maintaining consistently high production levels of heterologous proteins in Saccharomyces cerevisiae. In this study, we combined δ sequences for site-specific integration with TPI1 gene from Schizosaccharomyces pombe (POT1) as a selection marker to realize high-copy integration and stable expression of heterologous proteins in S. cerevisiae. With the newly developed POT1 platform, a 32-copy integration of enhanced green fluorescent protein (EGFP) expression cassette was obtained in a single round and was stably maintained after 100 generations of growth in a rich complex medium...
September 1, 2017: FEMS Yeast Research
https://www.readbyqxmd.com/read/28921510/development-of-a-formaldehyde-biosensor-with-application-to-synthetic-methylotrophy
#2
Benjamin M Woolston, Timothy Roth, Ishwar Kohale, David Liu, Gregory Stephanopoulos
Formaldehyde is a prevalent environmental toxin and a key intermediate in single carbon metabolism. The ability to monitor formaldehyde concentration is therefore of interest for both environmental monitoring and for metabolic engineering of native and synthetic methylotrophs, but current methods suffer from low sensitivity, complex workflows, or require expensive analytical equipment. Here we develop a formaldehyde biosensor based on the FrmR repressor protein and cognate promoter of E. coli. Optimization of the native repressor binding site and regulatory architecture enabled detection at levels as low as 1 µM...
September 16, 2017: Biotechnology and Bioengineering
https://www.readbyqxmd.com/read/28920402/-preparation-and-transformation-optimization-for-supercompetent-b-subtilis-sck6-cells
#3
Xinzhi Li, Zhenghui Lu, Yuling Zhou, Shiyu Li, Guimin Zhang
Bacillus subtilis is Gram-positive aerobic bacterium and widely used as a heterologous protein expression host because of its safety and high protein secretion property. However, comparing to Escherichia coli, the low transformation efficiency limits the application of B. subtilis as a host cell for directed evolution of heterologous enzymes. Therefore, we optimized the competent cell preparation conditions for conventional plasmid, including the alteration of the medium, the concentration of inducer, the plasmid type, and other parameters...
April 25, 2017: Sheng Wu Gong Cheng Xue Bao, Chinese Journal of Biotechnology
https://www.readbyqxmd.com/read/28920391/-progress-in-metabolic-engineering-of-%C3%AE-carotene-synthesis
#4
Yanyan Wang, Jianmin Xing, Hongge Chen
β-carotene is an important natural plant pigment and has various physiological functions in organisms. With the proposition of systematic biology and progress in carotenoids biosynthesis since the 1960s, metabolic engineering has played a significant role in enhancing carotenoid production. In this review, we present β-carotene's traditional production methods and metabolic engineering strategies for constructing β-carotene-producing strains. Meanwhile, main problems and corresponding solutions to improve β-carotene yield of engineered strains were further analyzed, for further efficient microbial production of β-carotene...
April 25, 2017: Sheng Wu Gong Cheng Xue Bao, Chinese Journal of Biotechnology
https://www.readbyqxmd.com/read/28920015/working-with-bacteria-and-putting-bacteria-to-work-the-biopolitics-of-synthetic-biology-for-energy-in-the-united-kingdom
#5
Carmen McLeod, Brigitte Nerlich, Alison Mohr
The UK government has made significant investment into so called 'fourth-generation' biofuel technologies. These biofuels are based on engineering the metabolic pathways of bacteria in order to create products compatible with existing infrastructure. Bacteria play an important role in what is promoted as a potentially new biological industrial revolution, which could address some of the negative environmental legacies of the last. This article presents results from ethnographic research with synthetic biologists who are challenged with balancing the curiosity-driven and intrinsically fulfilling scientific task of working with bacteria, alongside the policy-driven task of putting bacteria to work for extrinsic economic gains...
August 2017: Energy Research & Social Science
https://www.readbyqxmd.com/read/28918847/engineering-approaches-to-study-cancer-metabolism
#6
EDITORIAL
Christian M Metallo, Ralph J Deberardinis
No abstract text is available yet for this article.
September 2017: Metabolic Engineering
https://www.readbyqxmd.com/read/28918508/metabolic-engineering-of-schizosaccharomyces-pombe-to-produce-punicic-acid-a-conjugated-fatty-acid-with-nutraceutic-properties
#7
Martina Garaiova, Elzbieta Mietkiewska, Randall J Weselake, Roman Holic
Punicic acid (PuA) is a conjugated linolenic acid (C18:3Δ(9c,11t,13c)) with a wide range of nutraceutic effects with the potential to reduce the incidence of a number of health disorders including diabetes, obesity, and cancer. It is the main component of seed oil from Punica granatum and Trichosanthes kirilowii. Previously, production of relatively high levels of this unusual fatty acid in the seed oil of transgenic Arabidopsis thaliana plant was accomplished by the use of A. thaliana fad3/fae1 mutant high in linoleic acid (18:2∆(9c,12c)) and by co-expression of P...
September 16, 2017: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/28917970/how-do-enzymes-meet-nanoparticles-and-nanomaterials
#8
REVIEW
Ming Chen, Guangming Zeng, Piao Xu, Cui Lai, Lin Tang
Enzymes are fundamental biological catalysts responsible for biological regulation and metabolism. The opportunity for enzymes to 'meet' nanoparticles and nanomaterials is rapidly increasing due to growing demands for applications in nanomaterial design, environmental monitoring, biochemical engineering, and biomedicine. Therefore, understanding the nature of nanomaterial-enzyme interactions is becoming important. Since 2014, enzymes have been used to modify, degrade, or make nanoparticles/nanomaterials, while numerous nanoparticles/nanomaterials have been used as materials for enzymatic immobilization and biosensors and as enzyme mimicry...
September 13, 2017: Trends in Biochemical Sciences
https://www.readbyqxmd.com/read/28917932/rewiring-neutral-lipids-production-for-the-de-novo-synthesis-of-wax-esters-in-rhodococcus-opacus-pd630
#9
Mariana P Lanfranconi, Héctor M Alvarez
Rhodococcus opacus PD630 accumulates significant amounts of triacylglycerols (TAG), but is not able to de novo synthesize wax esters (WE) from structural unrelated carbon sources, such as gluconate. In this study, strain PD630 was engineered to produce WE by heterologous expression of maqu_2220 gene, which encodes a fatty acyl-CoA reductase for the production of fatty alcohols in Marinobacter hydrocarbonoclasticus. Recombinant cells produced ca. 46% of WE and 54% of TAG (of total WE+TAG) from gluconate compared with the wild type, which produced 100% of TAG...
September 13, 2017: Journal of Biotechnology
https://www.readbyqxmd.com/read/28917797/a-rapid-and-specific-colorimetric-method-for-free-tryptophan-quantification
#10
Yinan Wu, Tianmin Wang, Chong Zhang, Xin-Hui Xing
Tryptophan is one of the eight essential amino acids and plays an important role in many biological processes. For its interaction with human health, environment and relevant commercial interest in biotechnology-based production, rapid and specific quantification method for this molecule accessible to common laboratories is badly needed. We herein reported a simple colorimetric method for free tryptophan quantification with 96-well-plate-level throughput. Our protocol firstly converted tryptophan to indole enzymatically by purified tryptophanases and then used reactivity of indole with hydroxylamine to form pink product with absorption peak at 530nm, enabling the quantification of tryptophan with simple spectrometry in just two hours...
January 1, 2018: Talanta
https://www.readbyqxmd.com/read/28916561/succinate-transport-is-not-essential-for-symbiotic-nitrogen-fixation-by-sinorhizobium-meliloti-nor-rhizobium-leguminosarum
#11
Michael J Mitsch, George C diCenzo, Alison Cowie, Turlough M Finan
Symbiotic nitrogen fixation (SNF) is an energetically expensive process performed by bacteria during endosymbiotic relationships with plants. The bacteria require the plant to provide a carbon source for generation of reductant to power SNF. While C4-dicarboxylates (succinate, fumarate, malate) appear to be the primary, if not sole, carbon source provided to the bacteria, the contribution of each C4-dicarboxylate is not known. We address this issue using a genetic and systems-level analyses. Expression of a malate specific transporter (MaeP) in Sinorhizobium meliloti Rm1021 dct mutants unable to transport C4-dicarboxylates resulted in malate import rates up to 30% that of wild type...
September 15, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28916461/metabolic-engineering-of-escherichia-coli-for-the-synthesis-of-the-quadripolymer-poly-glycolate-co-lactate-co-3-hydroxybutyrate-co-4-hydroxybutyrate-from-glucose
#12
Zheng-Jun Li, Kangjian Qiao, Xue-Mei Che, Gregory Stephanopoulos
Escherichia coli was metabolically engineered to effectively produce a series of biopolymers consisted of four types of monomers including glycolate, lactate, 3-hydroxybutyrate and 4-hydroxybutyrate from glucose as the carbon source. The biosynthetic route of novel quadripolymers was achieved by the overexpression of a range of homologous and heterologous enzymes including isocitrate lyase, isocitrate dehydrogenase kinase/phosphatase, glyoxylate/hydroxypyruvate reductase, propionyl-CoA transferase, β-ketothiolase, acetoacetyl-CoA reductase, succinate semialdehyde dehydrogenase, 4-hydroxybutyrate dehydrogenase, CoA transferase and PHA synthase...
September 12, 2017: Metabolic Engineering
https://www.readbyqxmd.com/read/28915575/hexokinase-2-promotes-tumor-growth-and-metastasis-by-regulating-lactate-production-in-pancreatic-cancer
#13
Marybeth Anderson, Raoud Marayati, Richard Moffitt, Jen Jen Yeh
Pancreatic ductal adenocarcinoma (PDAC) is a KRAS-driven cancer with a high incidence of metastasis and an overall poor prognosis. Previous work in a genetically engineered mouse model of PDAC showed glucose metabolism to be important for maintaining tumor growth. Multiple glycolytic enzymes, including hexokinase 2 (HK2), were upregulated in primary PDAC patient tumors, supporting a role for glycolysis in promoting human disease. HK2 was most highly expressed in PDAC metastases, suggesting a link between HK2 and aggressive tumor biology...
August 22, 2017: Oncotarget
https://www.readbyqxmd.com/read/28915277/a-portable-bioelectronic-sensing-system-bessy-for-environmental-deployment-incorporating-differential-microbial-sensing-in-miniaturized-reactors
#14
Alyssa Y Zhou, Moshe Baruch, Caroline M Ajo-Franklin, Michel M Maharbiz
Current technologies are lacking in the area of deployable, in situ monitoring of complex chemicals in environmental applications. Microorganisms metabolize various chemical compounds and can be engineered to be analyte-specific making them naturally suited for robust chemical sensing. However, current electrochemical microbial biosensors use large and expensive electrochemistry equipment not suitable for on-site, real-time environmental analysis. Here we demonstrate a miniaturized, autonomous bioelectronic sensing system (BESSY) suitable for deployment for instantaneous and continuous sensing applications...
2017: PloS One
https://www.readbyqxmd.com/read/28915025/structural-evidence-for-the-dopamine-first-mechanism-of-norcoclaurine-synthase
#15
Benjamin R Lichman, Altin Sula, Thomas Pesnot, Helen C Hailes, John Ward, Nicholas H Keep
Norcoclaurine synthase (NCS) is a Pictet-Spenglerase that catalyzes the first key step in plant benzylisoquinoline alkaloid metabolism, a compound family that includes bioactive natural products such as morphine. The enzyme has also shown great potential as a biocata-lyst for the formation of chiral isoquinolines. Here we present new high-resolution X-ray crystallography data describing Thalictrum flavum NCS bound to a mechanism inspired ligand. The structure supports two key features of the NCS 'dopamine-first' mechanism: the binding of dopamine catechol to Lys-122 and the position of the carbonyl substrate binding site at the active site entrance...
September 15, 2017: Biochemistry
https://www.readbyqxmd.com/read/28914771/geminiviruses-and-plant-hosts-a-closer-examination-of-the-molecular-arms-race
#16
REVIEW
Shunmugiah V Ramesh, Pranav P Sahu, Manoj Prasad, Shelly Praveen, Hanu R Pappu
Geminiviruses are plant-infecting viruses characterized by a single-stranded DNA (ssDNA) genome. Geminivirus-derived proteins are multifunctional and effective regulators in modulating the host cellular processes resulting in successful infection. Virus-host interactions result in changes in host gene expression patterns, reprogram plant signaling controls, disrupt central cellular metabolic pathways, impair plant's defense system, and effectively evade RNA silencing response leading to host susceptibility...
September 15, 2017: Viruses
https://www.readbyqxmd.com/read/28910985/yeast-bacteria-competition-induced-new-metabolic-traits-through-large-scale-genomic-rearrangements-in-lachancea-kluyveri
#17
Nerve Zhou, Samuele Bottagisi, Michael Katz, Joseph Schacherer, Anne Friedrich, Zoran Gojkovic, Krishna B S Swamy, Wolfgang Knecht, Concetta Compagno, Jure Piškur
Large-scale chromosomal rearrangements are an important source of evolutionary novelty that may have reshaped the genomes of existing yeast species. They dramatically alter genome organization and gene expression fueling a phenotypic leap in response to environmental constraints. Although the emergence of such signatures of genetic diversity is thought to be associated with human exploitation of yeasts, less is known about the driving forces operating in natural habitats. Here we hypothesize that an ecological battlefield characteristic of every autumn when fruits ripen accounts for the genomic innovations in natural populations...
September 1, 2017: FEMS Yeast Research
https://www.readbyqxmd.com/read/28905106/recombinant-mouse-osteocalcin-secreted-by-lactococcus-lactis-promotes-glucagon-like-peptide-1-induction-in-stc-1-cells
#18
Fu Namai, Suguru Shigemori, Koichi Sudo, Takashi Sato, Yoshinari Yamamoto, Shireen Nigar, Tasuku Ogita, Takeshi Shimosato
An osteoblastic protein, osteocalcin (OC), exists in vivo in two forms: carboxylated OC, and uncarboxylated or low-carboxylated OC (ucOC). ucOC acts as a hormone to regulate carbon and energy metabolism. Recent studies demonstrated that ucOC exerts insulinotropic effects, mainly through the glucagon-like peptide 1 (GLP-1) pathway. GLP-1 is an insulinotropic hormone secreted by enteroendocrine L cells in the small intestine. Thus, efficient delivery of ucOC to the small intestine may be a new therapeutic option for metabolic diseases such as diabetes and obesity...
September 13, 2017: Current Microbiology
https://www.readbyqxmd.com/read/28902886/metabolic-engineering-to-simultaneously-activate-anthocyanin-and-proanthocyanidin-biosynthetic-pathways-in-nicotiana-spp
#19
Sandra Fresquet-Corrales, Edelín Roque, Alejandro Sarrión-Perdigones, Maricruz Rochina, María P López-Gresa, Huertas M Díaz-Mula, José M Bellés, Francisco Tomás-Barberán, José P Beltrán, Luis A Cañas
Proanthocyanidins (PAs), or condensed tannins, are powerful antioxidants that remove harmful free oxygen radicals from cells. To engineer the anthocyanin and proanthocyanidin biosynthetic pathways to de novo produce PAs in two Nicotiana species, we incorporated four transgenes to the plant chassis. We opted to perform a simultaneous transformation of the genes linked in a multigenic construct rather than classical breeding or retransformation approaches. We generated a GoldenBraid 2.0 multigenic construct containing two Antirrhinum majus transcription factors (AmRosea1 and AmDelila) to upregulate the anthocyanin pathway in combination with two Medicago truncatula genes (MtLAR and MtANR) to produce the enzymes that will derivate the biosynthetic pathway to PAs production...
2017: PloS One
https://www.readbyqxmd.com/read/28901274/revalorizing-lignocellulose-for-the-production-of-natural-pharmaceuticals-and-other-high-value-bioproducts
#20
Heng-Phon Too, Congqiang Zhang
Lignocellulose is the most plentiful, renewable natural resource on earth and has been successfully used for the production of biofuels. A significant challenge is to develop cost-effective, environmentally friendly and efficient processes for the conversion of lignocellulose material into suitable substrates for biotransformation. A number of approaches have been explored to convert lignocellulose into sugars, e.g. combining chemical pretreatment and enzymatic hydrolysis. In nature, there are organisms that can biotransform the complex lignocellulose efficiently, such as wood-degrading fungi (brown rot and white rot fungi), bacteria (e...
September 11, 2017: Current Medicinal Chemistry
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