Coenzyme Q10 (CoQ10) is a lipophilic antioxidant that improves human immunity, delays senility and enhances the vitality of the human body and has wide applications in pharmaceutical and cosmetic industries. Microbial fermentation is a sustainable way to produce CoQ10, and attracts increased interest. In this work, the native CoQ8 synthetic pathway of Escherichia coli was replaced by the CoQ10 synthetic pathway through integrating decaprenyl diphosphate synthase gene (dps) from Rhodobacter sphaeroides into chromosome of E. coli ATCC 8739, followed by deletion of the native octaprenyl diphosphate synthase gene (ispB). The resulting strain GD-14 produced 0.68 mg/L CoQ10 with a yield of 0.54 mg/g DCW. Modulation of dxs and idi genes of the MEP pathway and ubiCA genes in combination led to 2.46-fold increase of CoQ10 production (from 0.54 to 1.87 mg/g DCW). Recruiting glucose facilitator protein of Zymomonas mobilis to replace the native phosphoenolpyruvate: carbohydrate phosphotransferase systems (PTS) further led to a 16% increase of CoQ10 yield. Finally, fed-batch fermentation of the best strain GD-51 was performed, which produced 433 mg/L CoQ10 with a yield of 11.7 mg/g DCW. To the best of our knowledge, this was the highest CoQ10 titer and yield obtained for engineered E. coli.
Alkyl and Aryl Transferases ; genetics ; Bacterial Proteins ; genetics ; Batch Cell Culture Techniques ; Escherichia coli ; genetics ; metabolism ; Fermentation ; Gene Deletion ; Industrial Microbiology ; Metabolic Engineering ; Rhodobacter sphaeroides ; enzymology ; genetics ; Ubiquinone ; analogs & derivatives ; biosynthesis ; Zymomonas ; genetics

β-carotene belongs to carotenoids family, widely applied in pharmaceuticals, neutraceuticals, cosmetics and food industries. In this study, three key genes (dxs, idi, and crt operon) within β-carotene synthetic pathway in recombinant Escherichia coli strain CAR005 were modulated with RBS Library to improve β-carotene production. There were 7%, 11% and 17% increase of β-carotene yield respectively after modulating dxs, idi and crt operon genes with RBS Library, demonstrating that modulating gene expression with regulatory parts libraries would have more opportunities to obtain optimal production of target compound. Combined modulation of crt operon, dxs and idi genes led to 35% increase of β-carotene yield compared to parent strain CAR005. The optimal gene expression strength identified in single gene modulation would not be the optimal strength when used in combined modulation. Our study provides a new strategy for improving production of target compound through modulation of gene expression.
Escherichia coli ; metabolism ; Gene Expression ; Gene Library ; Operon ; beta Carotene ; biosynthesis

To report the clinical, imaging, and pathological feature of a rare case of central precocious puberty with primary pigmented nodular adrenocortical disease(PPNAD), and to conduct a retrospective analysis of PPNAD with relevant literatures. The pubic hair was found in the child for more than one year. Physical examination showed Cushing′s syndrome. ACTH in blood decreased, cortisol rhythm was disordered, 24-hour urine free cortisol increased and the paradoxical increase of urine free cortisol after high dose dexamethasone suppression test. Adrenal enhancement computed tomography(CT)showed multiple small nodular shadows in bilateral adrenal glands. Gonadotropin releasing hormone(GnRH)stimulation test supported central precocious puberty and GnRH analogue was used to control the sexual development. PPNAD was supported by pathology result. The symptoms of Cushing′s syndrome were relieved partially after left adrenalectomy.

Thyroid nodules in children exhibit differences in pathophysiology,clinical manifestation,and long-term outcomes compared with those in adults.Besides,the treatment which may be recommended for adults may not be suitable for children who are at low risk for death but at higher risk for long-term harm from exceedingly aggressive therapy.The evaluation of thyroid nodules includes risk factors,thyroid-related hormone,thyroid ultrasound and fineneedle aspiration biopsy,and so on.Benign lesions should be observed mainly by follow-up,however,for malignant lesions,total thyroidectomy or near is recommended,surveillance and follow-up should be maintained after thyroidectomy.

Objective:To analyze the patients′ clinical and genetic characteristics with pseudohypoparathyroidism (PHP) and investigate the correlation between clinical phenotypes and genotypes.Methods:Twenty PHP patients were ascertained at Children′s Hospital Zhejiang University School of Medicine from January 2011 to July 2020. Clinical manifestation, laboratory examination and gene test results were retrospectively analyzed.Results:In these twenty patients, eighteen cases showed resistance to parathyroid hormone (PTH) and thirteen cases had Albright′s hereditary osteodystrophy (AHO) phenotype. Gene abnormalities were found in all the twenty PHP patients, which included seven patients with GNAS gene variations (six frameshifts and one missense) and thirteen patients with GNAS gene methylation defects. Moreover, twelve children with both PTH resistance and AHO phenotype were clinically diagnosed as PHP-Ⅰa, meanwhile, seven carried GNAS variations and five had methylation abnormalities with a correct diagnosis of PHP-Ⅰb.Conclusions:Patients with AHO phenotype and PTH resistance may have a high genetic diagnosis rate. Because PHP-Ⅰb clinical phenotype may be similar to PHP-Ⅰa, early genetic detection is required for the differential diagnosis. In addition, children without PTH resistance should also be followed up regularly, which may help the early diagnosis.