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1.
Am J Pathol ; 192(6): 847-861, 2022 06.
Article in English | MEDLINE | ID: mdl-35367201

ABSTRACT

Although recent reports have revealed the importance of the inactivation of both RB1 and TP53 in the transformation from lung adenocarcinoma into neuroendocrine carcinoma (NEC), the requirements for complete transformation into NEC have not been elucidated. To investigate alterations in the characteristics associated with the inactivation of RB1/TP53 and define the requirements for transformation into NEC cells, RB1/TP53 double-knockout A549 lung adenocarcinoma cells were established, and additional knockout of REST and transfection of ASCL1 and POU class 3 homeobox transcription factors (TFs) was conducted. More than 60 genes that are abundantly expressed in neural cells and several genes associated with epithelial-to-mesenchymal transition were up-regulated in RB1/TP53 double-knockout A549 cells. Although the expression of chromogranin A and synaptophysin was induced by additional knockout of REST (which mimics the status of most NECs), the expression of another neuroendocrine marker, CD56, and proneural TFs was not induced. However, coexpression of ASCL1 and POU3F4 in RB1/TP53/REST triple-knockout A549 cells induced the expression of not only CD56 but also other proneural TFs (NEUROD1 and insulinoma-associated 1) and induced NEC-like morphology. These findings suggest that the inactivation of RB1 and TP53 induces a state necessary for the transformation of lung adenocarcinoma into NEC and that further inactivation of REST and coexpression of ASCL1 and POU3F4 are the triggers for complete transformation into NEC.


Subject(s)
Adenocarcinoma of Lung , Carcinoma, Neuroendocrine , Lung Neoplasms , Neuroendocrine Cells , Small Cell Lung Carcinoma , Adenocarcinoma of Lung/pathology , Basic Helix-Loop-Helix Transcription Factors/genetics , Basic Helix-Loop-Helix Transcription Factors/metabolism , Carcinoma, Neuroendocrine/genetics , Carcinoma, Neuroendocrine/metabolism , Carcinoma, Neuroendocrine/pathology , Humans , Infant, Newborn , Lung Neoplasms/pathology , Neuroendocrine Cells/metabolism , POU Domain Factors/metabolism , Retinoblastoma Binding Proteins , Small Cell Lung Carcinoma/genetics , Small Cell Lung Carcinoma/metabolism , Small Cell Lung Carcinoma/pathology , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Protein p53/metabolism , Ubiquitin-Protein Ligases/genetics
2.
Metab Eng ; 72: 68-81, 2022 07.
Article in English | MEDLINE | ID: mdl-35257866

ABSTRACT

Escherichia coli, the most studied prokaryote, is an excellent host for producing valuable chemicals from renewable resources as it is easy to manipulate genetically. Since the periplasmic environment can be easily controlled externally, elucidating how the localization of specific proteins or small molecules in the periplasm affects metabolism may lead to bioproduction development using E. coli. We investigated metabolic changes and its mechanisms occurring when specific proteins are localized to the E. coli periplasm. We found that the periplasmic localization of ß-glucosidase promoted the shikimate pathway involved in the synthesis of aromatic chemicals. The periplasmic localization of other proteins with an affinity for glucose-6-phosphate (G6P), such as inactivated mutants of Pgi, Zwf, and PhoA, similarly accelerated the shikimate pathway. Our results indicate that G6P is transported from the cytoplasm to the periplasm by the glucose transporter protein EIICBGlc, and then captured by ß-glucosidase.


Subject(s)
Cellulases , Escherichia coli Proteins , Cellulases/metabolism , Escherichia coli/metabolism , Escherichia coli Proteins/genetics , Escherichia coli Proteins/metabolism , Glucose-6-Phosphate/metabolism , Periplasm/genetics
3.
Metab Eng ; 67: 1-10, 2021 09.
Article in English | MEDLINE | ID: mdl-34044138

ABSTRACT

Microbial metabolic pathway engineering is a potent strategy used worldwide to produce aromatic compounds. We drastically rewired the primary metabolic pathway of Escherichia coli to produce aromatics and their derivatives. The metabolic pathway of E. coli was compartmentalized into the production and energy modules. We focused on the pyruvate-forming reaction in the biosynthesis pathway of some compounds as the reaction connecting those modules. E. coli strains were engineered to show no growth unless pyruvate was synthesized along with the compounds of interest production. Production of salicylate and maleate was demonstrated to confirm our strategy's versatility. In maleate production, the production, yield against the theoretical yield, and production rate reached 12.0 g L-1, 67%, and up to fourfold compared to that in previous reports, respectively; these are the highest values of maleate production in microbes to our knowledge. The results reveal that our strategy strongly promotes the production of aromatics and their derivatives.


Subject(s)
Escherichia coli , Pyruvic Acid , Escherichia coli/genetics , Metabolic Engineering , Metabolic Networks and Pathways
4.
Biotechnol Bioeng ; 117(7): 2153-2164, 2020 07.
Article in English | MEDLINE | ID: mdl-32255505

ABSTRACT

Microbial production of mevalonate from renewable feedstock is a promising and sustainable approach for the production of value-added chemicals. We describe the metabolic engineering of Escherichia coli to enhance mevalonate production from glucose and cellobiose. First, the mevalonate-producing pathway was introduced into E. coli and the expression of the gene atoB, which encodes the gene for acetoacetyl-CoA synthetase, was increased. Then, the deletion of the pgi gene, which encodes phosphoglucose isomerase, increased the NADPH/NADP+ ratio in the cells but did not improve mevalonate production. Alternatively, to reduce flux toward the tricarboxylic acid cycle, gltA, which encodes citrate synthetase, was disrupted. The resultant strain, MGΔgltA-MV, increased levels of intracellular acetyl-CoA up to sevenfold higher than the wild-type strain. This strain produced 8.0 g/L of mevalonate from 20 g/L of glucose. We also engineered the sugar supply by displaying ß-glucosidase (BGL) on the cell surface. When cellobiose was used as carbon source, the strain lacking gnd displaying BGL efficiently consumed cellobiose and produced mevalonate at 5.7 g/L. The yield of mevalonate was 0.25 g/g glucose (1 g of cellobiose corresponds to 1.1 g of glucose). These results demonstrate the feasibility of producing mevalonate from cellobiose or cellooligosaccharides using an engineered E. coli strain.


Subject(s)
Escherichia coli/metabolism , Metabolic Engineering/methods , Mevalonic Acid/metabolism , NADP/metabolism , Escherichia coli/genetics , Industrial Microbiology/methods
5.
Microb Cell Fact ; 18(1): 124, 2019 Jul 18.
Article in English | MEDLINE | ID: mdl-31319852

ABSTRACT

BACKGROUND: The microbial production of useful fuels and chemicals has been widely studied. In several cases, glucose is used as the raw material, and almost all microbes adopt the Embden-Meyerhof (EM) pathway to degrade glucose into compounds of interest. Recently, the Entner-Doudoroff (ED) pathway has been gaining attention as an alternative strategy for microbial production. RESULTS: In the present study, we attempted to apply the ED pathway for isobutanol production in Escherichia coli because of the complete redox balance involved. First, we generated ED pathway-dependent isobutanol-producing E. coli. Thereafter, the inactivation of the genes concerning organic acids as the byproducts was performed to improve the carbon flux to isobutanol from glucose. Finally, the expression of the genes concerning the ED pathway was modified. CONCLUSIONS: The optimized isobutanol-producing E. coli produced 15.0 g/L of isobutanol as the final titer, and the yield from glucose was 0.37 g/g (g-glucose/g-isobutanol).


Subject(s)
Butanols/metabolism , Escherichia coli/metabolism , Metabolic Engineering/methods , Metabolic Networks and Pathways , Escherichia coli/genetics , Escherichia coli Proteins/genetics , Glucose/metabolism
6.
Metab Eng ; 33: 119-129, 2016 Jan.
Article in English | MEDLINE | ID: mdl-26654797

ABSTRACT

A synthetic metabolic pathway suitable for the production of chorismate derivatives was designed in Escherichia coli. An L-phenylalanine-overproducing E. coli strain was engineered to enhance the availability of phosphoenolpyruvate (PEP), which is a key precursor in the biosynthesis of aromatic compounds in microbes. Two major reactions converting PEP to pyruvate were inactivated. Using this modified E.coli as a base strain, we tested our system by carrying out the production of salicylate, a high-demand aromatic chemical. The titer of salicylate reached 11.5 g/L in batch culture after 48 h cultivation in a 2-liter jar fermentor, and the yield from glucose as the sole carbon source exceeded 40% (mol/mol). In this test case, we found that pyruvate was synthesized primarily via salicylate formation and the reaction converting oxaloacetate to pyruvate. In order to demonstrate the generality of our designed strain, we employed this platform for the production of each of 7 different chorismate derivatives. Each of these industrially important chemicals was successfully produced to levels of 1-3g/L in test tube-scale culture.


Subject(s)
Chorismic Acid/metabolism , Escherichia coli Proteins/metabolism , Escherichia coli/genetics , Escherichia coli/metabolism , Metabolic Engineering/methods , Metabolic Flux Analysis/methods , Chorismic Acid/isolation & purification , Escherichia coli/classification , Escherichia coli Proteins/genetics , Genetic Enhancement/methods , Recombinant Proteins/metabolism , Signal Transduction/physiology , Species Specificity
7.
Biotechnol Lett ; 38(9): 1543-9, 2016 Sep.
Article in English | MEDLINE | ID: mdl-27206340

ABSTRACT

OBJECTIVES: To find a novel host for the production of 4-vinylphenol (4VPh) by screening Streptomyces species. RESULTS: The conversion of p-coumaric acid (pHCA) to 4VPh in Streptomyces mobaraense was evaluated using a medium containing pHCA. S. mobaraense readily assimilated pHCA after 24 h of cultivation to produce 4VPh. A phenolic acid decarboxylase, derived from S. mobaraense (SmPAD), was purified following heterologous expression in Escherichia coli. SmPAD was evaluated under various conditions, and the enzyme's kcat/Km value was 0.54 mM (-1) s(-1). Using intergenetic conjugation, a gene from Rhodobacter sphaeroides encoding a tyrosine ammonia lyase, which catalyzes the conversion of L-tyrosine to p-coumaric acid, was introduced into S. mobaraense. The resulting S. mobaraense transformant produced 273 mg 4VPh l(-1) from 10 g glucose l(-1). CONCLUSION: A novel strain suitable for the production of 4VPh and potentially other aromatic compounds was isolated.


Subject(s)
Ammonia-Lyases/metabolism , Glucose/metabolism , Phenols/metabolism , Rhodobacter sphaeroides/enzymology , Streptomyces/enzymology , Streptomyces/metabolism , Ammonia-Lyases/genetics , Coumaric Acids/metabolism , Propionates
8.
Microb Cell Fact ; 14: 5, 2015 Jan 13.
Article in English | MEDLINE | ID: mdl-25582841

ABSTRACT

BACKGROUND: Streptavidin is a tetrameric protein derived from Streptomyces avidinii, and has tight and specific biotin binding affinity. Applications of the streptavidin-biotin system have been widely studied. Streptavidin is generally produced using protein expression in Escherichia coli. In the present study, the secretory production of streptavidin was carried out using Streptomyces lividans as a host. RESULTS: In this study, we used the gene encoding native full-length streptavidin, whereas the core region is generally used for streptavidin production in E. coli. Tetrameric streptavidin composed of native full-length streptavidin monomers was successfully secreted in the culture supernatant of S. lividans transformants, and had specific biotin binding affinity as strong as streptavidin produced by E. coli. The amount of Sav using S. lividans was about 9 times higher than using E. coli. Surprisingly, streptavidin produced by S. lividans exhibited affinity to biotin after boiling, despite the fact that tetrameric streptavidin is known to lose its biotin binding ability after brief boiling. CONCLUSION: We successfully produced a large amount of tetrameric streptavidin as a secretory-form protein with unique thermotolerance.


Subject(s)
Streptavidin/metabolism , Streptomyces lividans/metabolism , Amino Acid Sequence , Biotin/chemistry , Biotin/metabolism , Electrophoresis, Polyacrylamide Gel , Molecular Sequence Data , Plasmids/genetics , Plasmids/metabolism , Protein Binding , Protein Stability , Protein Structure, Quaternary , Recombinant Proteins/biosynthesis , Recombinant Proteins/chemistry , Recombinant Proteins/isolation & purification , Streptavidin/chemistry , Streptavidin/genetics , Temperature
9.
BioTech (Basel) ; 13(1)2024 Jan 14.
Article in English | MEDLINE | ID: mdl-38247732

ABSTRACT

Styrene is an important industrial chemical. Although several studies have reported microbial styrene production, the amount of styrene produced in batch cultures can be increased. In this study, styrene was produced using genetically engineered Escherichia coli. First, we evaluated five types of phenylalanine ammonia lyases (PALs) from Arabidopsis thaliana (AtPAL) and Brachypodium distachyon (BdPAL) for their ability to produce trans-cinnamic acid (Cin), a styrene precursor. AtPAL2-expressing E. coli produced approximately 700 mg/L of Cin and we found that BdPALs could convert Cin into styrene. To assess styrene production, we constructed an E. coli strain that co-expressed AtPAL2 and ferulic acid decarboxylase from Saccharomyces cerevisiae. After a biphasic culture with oleyl alcohol, styrene production and yield from glucose were 3.1 g/L and 26.7% (mol/mol), respectively, which, to the best of our knowledge, are the highest values obtained in batch cultivation. Thus, this strain can be applied to the large-scale industrial production of styrene.

10.
Bioresour Technol ; 406: 130927, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38830477

ABSTRACT

2-Phenylethanol, known for its rose-like odor and antibacterial activity, is synthesized via exogenous phenylpyruvate by the sequential reaction of phenylpyruvate decarboxylase (PDC) and aldehyde reductase. We first targeted ARO10, a phenylpyruvate decarboxylase gene from Saccharomyces cerevisiae, and identified a suitable aldehyde reductase gene. Co-expression of ARO10 and yahK in E. coli transformants yielded 1.1 g/L of 2-phenylethanol in batch culture. We hypothesized that there might be a bottleneck in PDC activity. The computer-based enzyme evolution was utilized to enhance production. The introduction of an amino acid substitution in ARO10 (ARO10 I544W) stabilized the aromatic ring of the phenylpyruvate substrate, increasing 2-phenylethanol yield 4.1-fold compared to wild-type ARO10. Cultivation of ARO10 I544W-expressing E. coli produced 2.5 g/L of 2-phenylethanol with a yield from glucose of 0.16 g/g after 72 h. This approach represents a significant advancement, achieving the highest yield of 2-phenylethanol from glucose using microbes to date.


Subject(s)
Carboxy-Lyases , Escherichia coli , Metabolic Engineering , Phenylethyl Alcohol , Saccharomyces cerevisiae , Escherichia coli/metabolism , Escherichia coli/genetics , Phenylethyl Alcohol/metabolism , Metabolic Engineering/methods , Carboxy-Lyases/metabolism , Carboxy-Lyases/genetics , Saccharomyces cerevisiae/metabolism , Saccharomyces cerevisiae/genetics , Glucose/metabolism
11.
Int J Surg Pathol ; : 10668969241271963, 2024 Sep 17.
Article in English | MEDLINE | ID: mdl-39289950

ABSTRACT

We report a patient in whom a primary high-grade serous carcinoma (HGSC) of the fallopian tube transformed into a carcinosarcoma at the site of peritoneal dissemination, and immunohistological analysis suggested the involvement of an epithelial-mesenchymal transition (EMT). The patient, a 70-year-old woman, had an abdominal mass palpated on admission, and a laparotomy was performed after a close examination. The resected right fallopian tube was cystically dilated, and a solid mass was observed in its lumen. The histological diagnosis was HGSC of the right fallopian tube with a papillary or complex tubular structure composed of tumor cells with marked nuclear irregularities. p53 was overexpressed, and no mesenchymal tumor component was observed. The resected left-sided abdominal mass of the omentum was a solid with a long diameter of 100 mm. Microscopically, the tumor exhibited a mixture of HGSC and high-grade sarcoma with nonspecific differentiation. Furthermore, a heterologous chondrosarcoma was subsequently observed from the high-grade sarcoma. The HGSC component was E-cadherin positive. The high-grade sarcoma component was positive for EMT-related proteins such as zinc finger E-box-binding homeobox 1 (ZEB1) and twist family bHLH transcription factor 1 (TWIST1). The chondrosarcoma component was ZEB1 positive and TWIST1 negative. p53 overexpression was found in all 3 components. The tumor of the omentum suggested that an EMT phenomenon was involved in the tumorigenesis. In this scenario, the primary HGSC of the fallopian tube with obvious invasion demonstrated that the conversion from carcinoma to sarcoma by EMT occurs only with peritoneal dissemination.

12.
Biotechnol J ; 19(8): e2400210, 2024 Aug.
Article in English | MEDLINE | ID: mdl-39167552

ABSTRACT

The demand for the essential commodity chemical 1,2-propanediol (1,2-PDO) is on the rise, as its microbial production has emerged as a promising method for a sustainable chemical supply. However, the reliance of 1,2-PDO production in Escherichia coli on anaerobic conditions, as enhancing cell growth to augment precursor availability remains a substantial challenge. This study presents glucose-based aerobic production of 1,2-PDO, with xylose utilization facilitating cell growth. An engineered strain was constructed capable of exclusively producing 1,2-PDO from glucose while utilizing xylose to support cell growth. This was accomplished by deleting the gloA, eno, eda, sdaA, sdaB, and tdcG genes for 1,2-PDO production from glucose and introducing the Weimberg pathway for cell growth using xylose. Enhanced 1,2-PDO production was achieved via yagF overexpression and disruption of the ghrA gene involved in the 1,2-PDO-competing pathway. The resultant strain, PD72, produced 2.48 ± 0.15 g L-1 1,2-PDO with a 0.27 ± 0.02 g g-1-glucose yield after 72 h cultivation. Overall, this study demonstrates aerobic 1,2-PDO synthesis through the isolation of the 1,2-PDO synthetic pathway from the tricarboxylic acid cycle.


Subject(s)
Escherichia coli , Glucose , Metabolic Engineering , Metabolic Networks and Pathways , Escherichia coli/genetics , Escherichia coli/metabolism , Metabolic Engineering/methods , Glucose/metabolism , Metabolic Networks and Pathways/genetics , Propylene Glycol/metabolism , Xylose/metabolism , Aerobiosis , Escherichia coli Proteins/genetics , Escherichia coli Proteins/metabolism , Fermentation
13.
Diagn Cytopathol ; 52(6): E129-E133, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38454318

ABSTRACT

A mesonephric-like endometrial adenocarcinoma (ML-EAC) is very rare and has a worse prognosis than other endometrial carcinomas. We describe an ML-EAC and report our endometrial cytological findings. A 76-year-old woman presented with irregular genital bleeding and a uterine mass. Endometrial cytology revealed atypical cylindrical or spindle-shaped cells in the form of small aggregates or solitary cells. The cell aggregates exhibited irregularly stacked papillary structures, small glandular structures, and fenestrated structures. The atypical cells had a nucleus with fine-granular chromatin and a granular cytoplasm, and nuclear grooves and intranuclear pseudo-inclusions were present. Hyaline globules were observed in the glandular lumens and in the background. The presumptive histological type was an adenocarcinoma, but the cytological features were different from those of an endometrioid carcinoma. A histological examination of the endometrial biopsy revealed an adenocarcinoma, and a simple hysterectomy was performed. A grayish-white elevated mass measuring 90 mm × 70 mm × 40 mm was observed on the uterine corpus in the hysterectomy specimen. Histologically, the tumor proliferated as complex tubular structures containing eosinophilic colloid-like materials and trabecular structures. The tumor cells were diffuse and positive for GATA-3 and partially positive for thyroid transcription factor-1. Estrogen and progesterone receptors were negative. An ML-EAC was diagnosed. The tumor was invasive and extended beyond one-half of the muscle layer with a high degree of vascular invasion. In conclusion, we need to focus on the various shapes of the cell aggregate, nuclear grooves, and intranuclear pseudo-inclusions of tumor cells to distinguish an ML-EAC from other endometrial carcinomas in endometrial cytology.


Subject(s)
Adenocarcinoma , Endometrial Neoplasms , Humans , Female , Endometrial Neoplasms/pathology , Endometrial Neoplasms/diagnosis , Aged , Adenocarcinoma/pathology , Adenocarcinoma/diagnosis , Endometrium/pathology
14.
Microb Cell Fact ; 12: 88, 2013 Oct 01.
Article in English | MEDLINE | ID: mdl-24083334

ABSTRACT

BACKGROUND: Protein production as secretory-form is a powerful tool in industrial enzyme production due to the simple purification procedure. Streptomyces lividans is a versatile host for secretory production of useful proteins. In order to expand the amount of secreted protein, signal peptide sequences, which encourage protein secretion from inside cell to extracellular environment, are one of the most significant factors. In this study, we focused on Streptomyces lividans as a host strain to secrete useful proteins, and screened for signal peptides from the biomass-degradation enzymes derived from Thermobifida fusca YX and S. lividans. RESULTS: Three candidate signal peptides were isolated and evaluated for their protein secretion ability using ß-glucosidase derived from T. fusca YX, which is a non-secreted protein, as a model protein. Using S. lividans xylanase C signal peptide, the amount of produced the ß-glucosidase reached 10 times as much as that when using Streptomyces cinnamoneus phospholipase D signal peptide, which was identified as a versatile signal peptide in our previous report. In addition, the introduction of the ß-glucosidase fused to xylanase C signal peptide using two kinds of plasmid, pUC702 and pTYM18, led to further protein secretion, and the maximal level of produced the ß-glucosidase increased up to 17 times (1.1 g/l) compared to using only pUC702 carrying the ß-glucosidase fused to S. cinnamoneus phospholipase D signal peptide. CONCLUSION: In the present study, we focused on signal peptide sequences derived from biomass degradation enzymes, which are usually secreted into the culture supernatant, and screened for signal peptides leading to effective protein secretion. Using the signal peptides, the hyper-protein secretion system was successfully demonstrated for the cytoplasmic ß-glucosidase.


Subject(s)
Bacterial Proteins/metabolism , Protein Sorting Signals/genetics , Streptomyces lividans/enzymology , beta-Glucosidase/metabolism , Amino Acid Sequence , Bacterial Proteins/genetics , Gene Products, tat/genetics , Gene Products, tat/metabolism , Molecular Sequence Data , Protein Transport , Streptomyces lividans/genetics , Streptomyces lividans/metabolism , beta-Glucosidase/genetics
15.
Microb Cell Fact ; 12: 45, 2013 May 07.
Article in English | MEDLINE | ID: mdl-23651460

ABSTRACT

BACKGROUND: p-Hydroxycinnamic acid (pHCA) is an aromatic compound that serves as a starting material for the production of many commercially valuable chemicals, such as fragrances and pharmaceuticals, and is also used in the synthesis of thermostable polymers. However, chemical synthesis of pHCA is both costly and harmful to the environment. Although pHCA production using microbes has been widely studied, there remains a need for more cost-effective methods, such as the use of biomass as a carbon source. In this study, we produced pHCA using tyrosine ammonia lyase-expressing Streptomyces lividans. In order to improve pHCA productivity from cellulose, we constructed a tyrosine ammonia lyase- and endoglucanase (EG)-expressing S. lividans transformant and used it to produce pHCA from cellulose. RESULTS: A Streptomyces lividans transformant was constructed to express tyrosine ammonia lyase derived from Rhodobacter sphaeroides (RsTAL). The transformant produced 786 or 736 mg/L of pHCA after 7 days of cultivation in medium containing 1% glucose or cellobiose as the carbon source, respectively. To enhance pHCA production from phosphoric acid swollen cellulose (PASC), we introduced the gene encoding EG into RsTAL-expressing S. lividans. After 7 days of cultivation, this transformant produced 753, 743, or 500 mg/L of pHCA from 1% glucose, cellobiose, or PASC, respectively. CONCLUSIONS: RsTAL-expressing S. lividans can produce pHCA from glucose and cellobiose. Similarly, RsTAL- and EG-expressing S. lividans can produce pHCA from glucose and cellobiose with excess EG activity remaining in the supernatant. This transformant demonstrated improved pHCA production from cellulose. Further enhancements in the cellulose degradation capability of the transformant will be necessary in order to achieve further improvements in pHCA production from cellulose.


Subject(s)
Ammonia-Lyases/genetics , Bacterial Proteins/genetics , Cellulase/genetics , Cellulose/metabolism , Coumaric Acids/metabolism , Streptomyces lividans/metabolism , Ammonia-Lyases/metabolism , Bacterial Proteins/metabolism , Cellobiose/metabolism , Cellulase/metabolism , Coumaric Acids/chemistry , Glucose/metabolism , Plasmids/genetics , Plasmids/metabolism , Propionates , Rhodobacter sphaeroides/enzymology , Rhodobacter sphaeroides/genetics
16.
Appl Microbiol Biotechnol ; 97(13): 5711-20, 2013 Jul.
Article in English | MEDLINE | ID: mdl-23604559

ABSTRACT

We screened for high-activity endoglucanase (EG) as a first step toward the creation of cellulose-assimilating Streptomyces lividans transformants. EGs derived from Thermobifida fusca YX, Tfu0901, and S. lividans, cellulase B (CelB), were successfully expressed. Genes encoding Tfu0901 or CelB were introduced into S. lividans using the integrative vector pTYM18 and the high-copy-number vector pUC702, and EG activity was detected in the supernatant of each transformant. To achieve coexpression of EG and transglutaminase, the transglutaminase gene was introduced into EG-secreting S. lividans using pUC702. S. lividans coexpressing EG and transglutaminase effectively assimilated phosphoric acid swollen cellulose. The yield of Streptomyces cinnamoneus transglutaminase in the culture supernatant was 7.2 mg/L, which was 18 times higher than that of the control strain. To demonstrate the versatility of our system, we also created an EG-producing S. lividans transformant capable of coexpressing endoxylanase. The EG-secreting S. lividans transformants constructed here can be used to produce other useful compounds through cellulose fermentation.


Subject(s)
Carbon/metabolism , Cellulase/metabolism , Cellulose/metabolism , Metabolic Engineering/methods , Streptomyces lividans/enzymology , Streptomyces lividans/metabolism , Biotechnology/methods , Cellulase/genetics , Gene Expression , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Streptomyces lividans/genetics , Streptomyces lividans/growth & development , Transglutaminases/genetics , Transglutaminases/metabolism
17.
Nat Genet ; 35(3): 238-45, 2003 Nov.
Article in English | MEDLINE | ID: mdl-14517554

ABSTRACT

Transcription factor Nrf2 (encoded by Nfe2l2) regulates a battery of detoxifying and antioxidant genes, and Keap1 represses Nrf2 function. When we ablated Keap1, Keap1-deficient mice died postnatally, probably from malnutrition resulting from hyperkeratosis in the esophagus and forestomach. Nrf2 activity affects the expression levels of several squamous epithelial genes. Biochemical data show that, without Keap1, Nrf2 constitutively accumulates in the nucleus to stimulate transcription of cytoprotective genes. Breeding to Nrf2-deficient mice reversed the phenotypic Keap1 deficiencies. These experiments show that Keap1 acts upstream of Nrf2 in the cellular response to oxidative and xenobiotic stress.


Subject(s)
Adaptor Proteins, Signal Transducing , Carrier Proteins/physiology , Cytoskeletal Proteins , DNA-Binding Proteins/metabolism , Genes, Lethal , Mutation , Trans-Activators/metabolism , Animals , Carrier Proteins/genetics , Esophageal Diseases/genetics , Kelch-Like ECH-Associated Protein 1 , Keratins/metabolism , Membrane Proteins/metabolism , Mice , Mice, Knockout , NF-E2-Related Factor 2 , Stomach Diseases/genetics , Weaning
18.
J Biol Eng ; 17(1): 3, 2023 Jan 10.
Article in English | MEDLINE | ID: mdl-36627686

ABSTRACT

BACKGROUND: Flux Balance Analysis (FBA) is a well-known bioinformatics tool for metabolic engineering design. Previously, we have successfully used single-level FBA to design metabolic fluxes in Bacillus subtilis to enhance (R,R)-2,3-butanediol (2,3-BD) production from glycerol. OptKnock is another powerful technique for devising gene deletion strategies to maximize microbial growth coupling with improved biochemical production. It has never been used in B. subtilis. In this study, we aimed to compare the use of single-level FBA and OptKnock for designing enhanced 2,3-BD production from glycerol in B. subtilis. RESULTS: Single-level FBA and OptKnock were used to design metabolic engineering approaches for B. subtilis to enhance 2,3-BD production from glycerol. Single-level FBA indicated that deletion of ackA, pta, lctE, and mmgA would improve the production of 2,3-BD from glycerol, while OptKnock simulation suggested the deletion of ackA, pta, mmgA, and zwf. Consequently, strains LM01 (single-level FBA-based) and MZ02 (OptKnock-based) were constructed, and their capacity to produce 2,3-BD from glycerol was investigated. The deletion of multiple genes did not negatively affect strain growth and glycerol utilization. The highest 2,3-BD production was detected in strain LM01. Strain MZ02 produced 2,3-BD at a similar level as the wild type, indicating that the OptKnock prediction was erroneous. Two-step FBA was performed to examine the reason for the erroneous OptKnock prediction. Interestingly, we newly found that zwf gene deletion in strain MZ02 improved lactate production, which has never been reported to date. The predictions of single-level FBA for strain MZ02 were in line with experimental findings. CONCLUSIONS: We showed that single-level FBA is an effective approach for metabolic design and manipulation to enhance 2,3-BD production from glycerol in B. subtilis. Further, while this approach predicted the phenotypes of generated strains with high precision, OptKnock prediction was not accurate. We suggest that OptKnock modelling predictions be evaluated by using single-level FBA to ensure the accuracy of metabolic pathway design. Furthermore, the zwf gene knockout resulted in the change of metabolic fluxes to enhance the lactate productivity.

19.
Enzyme Microb Technol ; 171: 110321, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37696175

ABSTRACT

Nitroaromatic compounds are widely used in industry, but their production is associated with issues such as the hazardousness of the process and low regioselectivity. Here, we successfully demonstrated the production of p-nitrobenzoate (PNBA) from glucose by constructing p-aminobenzoate N-oxygenase AurF-expressing E. coli. We generated this strain, which we named PN-1 by disrupting four genes involved in PNBA degradation: nfsA, nfsB, nemA, and azoR. We then expressed AurF from Streptomyces thioluteus in this strain, which resulted in the production of 945 mg/L PNBA in the presence of 1 g/L p-aminobenzoate. Direct production of PNBA from glucose was achieved by co-expressing the pabA, pabB, and pabC, as well as aurF, resulting in the production of 393 mg/L PNBA from 20 g/L glucose. To improve the PNBA titer, we disrupted genes involved in competing pathways: pheA, tyrA, trpE, pykA, and pykF. The resultant strain PN-4Ap produced 975 mg/L PNBA after 72 h of cultivation. These results highlight the potential of using microorganisms to produce other nitroaromatic compounds.

20.
Enzyme Microb Technol ; 164: 110193, 2023 Mar.
Article in English | MEDLINE | ID: mdl-36621069

ABSTRACT

Caffeic acid (3,4-dihydroxycinnamic acid) is a precursor for high-valued compounds with anticancer, antiviral activities, and anti-inflammatory making it an important substance in the food additive, cosmetics, and pharmaceutical industries. Here, we developed an engineered Escherichia coli strain capable of directly producing high levels of caffeic acid from glucose. Tyrosine ammonia-lyase from Rhodotorula glutinis (RgTAL) and p-coumaric acid 3-hydroxylase from Saccharothrix espanaensis (SeC3H) were expressed. Next, feedback-resistant chorismate mutase/prephenate dehydrogenase, was introduced to promote l-tyrosine synthesis. This engineered strain CA3 produced 1.58 g/L of caffeic acid from glucose without tyrosine supplemented to the medium. Furthermore, to reduce p-coumaric acid accumulation, 4-hydroxyphenylacetate 3-hydroxylase from Pseudomonas aeruginosa (PaHpaBC) was introduced. Finally, an engineered strain CA8 directly produced 6.17 g/L of caffeic acid from glucose using a jar fermenter. The E. coli developed in this study would be helpful as a chassis strain to produce value-added caffeic acid-derivatives.


Subject(s)
Caffeic Acids , Escherichia coli , Glucose , Metabolic Engineering , Escherichia coli/genetics , Escherichia coli/metabolism , Mixed Function Oxygenases , Caffeic Acids/metabolism
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