Publications by authors named "Chengjia Xie"

8 Publications

  • Page 1 of 1

Pathway engineering of Saccharomyces cerevisiae for efficient lycopene production.

Bioprocess Biosyst Eng 2021 Jun 24;44(6):1033-1047. Epub 2021 Jan 24.

College of Food Science and Light Industry, Nanjing Tech University, Nanjing, 211816, Jiangsu, China.

To construct a Saccharomyces cerevisiae strain for efficient lycopene production, we used a pathway engineering strategy based on expression modules comprising fusion proteins and a strong constitutive promoter. The two recombinant plasmids pEBI encoding the fusion genes with an inducible promoter, as well as pIETB with a constitutive promoter and terminator were introduced into S. cerevisiae YPH499 and BY4741 to obtain the four recombinant strains ypEBI, ypIETB, byEBI and byIETB. The lycopene production and the transcription levels of key genes were higher in the BY4741 chassis than in YPH499. Accordingly, the content of total and unsaturated fatty acids was also higher in BY4741, which also exhibited a decrease of glucose, increase of trehalose, increase of metabolite in citrate cycle, and low levels of amino acids. These changes rerouted metabolic fluxes toward lycopene synthesis, indicating that the BY4741 chassis was more suitable for lycopene synthesis. The lycopene content of bpIETB in SG-Leu medium supplemented with 100 mg/L of linolenic acid reached 10.12 mg/g dry cell weight (DCW), which was 85.7% higher than without the addition of unsaturated fatty acids. The constitutive promoter expression strategy employed in this study achieved efficient lycopene synthesis in S. cerevisiae, and the strain bpIETB was obtained a suitable chassis host for lycopene production, which provides a basis for further optimization of lycopene production in artificial synthetic cells and a reference for the multi-enzyme synthesis of other similar complex terpenoids.
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http://dx.doi.org/10.1007/s00449-020-02503-5DOI Listing
June 2021

Design and tailoring of an artificial DNA scaffolding system for efficient lycopene synthesis using zinc-finger-guided assembly.

J Ind Microbiol Biotechnol 2020 Feb 18;47(2):209-222. Epub 2019 Dec 18.

College of Food Science and Light Industry, Nanjing Tech University, Nanjing, 211816, Jiangsu Province, China.

A highly efficient lycopene production system was constructed by assembling enzymes fused to zinc-finger motifs on DNA scaffolds in vitro and in vivo. Three key enzymes of the lycopene synthesis pathway, geranylgeranyl diphosphate synthase, phytoene synthase, and phytoene desaturase, were fused with zinc-finger proteins, expressed and purified. Recombinant plasmids of the pS series containing DNA scaffolds that the zinc-finger proteins can specifically bind to were constructed. In the in vitro system, the production efficiency of lycopene was improved greatly after the addition of the scaffold plasmid pS231. Subsequently, the plasmid pET-AEBI was constructed and introduced into recombinant Escherichia coli BL21 (DE3) for expression, together with plasmids of the pS series. The lycopene production rate and content of the recombinant strain pp231 were higher than that of all strains carrying the DNA scaffold and the control. With the addition of cofactors and substrates in the lycopene biosynthesis pathway, the lycopene yield of pp231 reached 632.49 mg/L at 40 h, representing a 4.7-fold increase compared to the original recombinant strain pA1A3. This DNA scaffold system can be used as a platform for the construction and production of many biochemicals synthesized via multi-enzyme cascade reactions.
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http://dx.doi.org/10.1007/s10295-019-02255-6DOI Listing
February 2020

Hydroxyapatite nanowires modified polylactic acid membrane plays barrier/osteoinduction dual roles and promotes bone regeneration in a rat mandible defect model.

J Biomed Mater Res A 2018 12 16;106(12):3099-3110. Epub 2018 Oct 16.

Shandong Provincial Key Laboratory of Oral Tissue Regeneration, School of Stomatology, Shandong University, Jinan, 250012, China.

Periodontitis is an inflammatory disease leading to tooth loss, alveolar bone absorption and disorder of masticatory function. Guided tissue regeneration (GTR) is one of the most common strategies for regeneration of lost periodontium. During surgical process, barrier membranes, and osteoinductive/osteoconductive materials should be placed, respectively, which may increase risks of infection, bleeding, and difficulty of operation. Here, we introduced a new kind of hydroxyapatite (HAp) nanowires modified polylactic acid (PLA) membrane to achieve barrier/osteoinduction dual functions. The physicochemical property measurements suggested the two sides of the composite membrane did not change after composition. Then a rat mandibular defect model was established to investigate barrier and osteoinductive effects of this composite membrane. After implantation, effects of functional cells engraftment and osteoinduction were detected by scanning electron microscope (SEM), histomorphometric measurement, immunohistochemical staining, and Micro-CT scanning. SEM images showed HAp side engrafted more cells than PLA side. The result of immunohistochemical staining suggested HAp/PLA promoted the expression of bone-related markers. Moreover, there were more newly formed bones with better quality in HAp/PLA group. Therefore, this composite membrane would be a promising biomaterial in tissue engineering for bone regeneration due to its barrier/osteoinduction dual functions. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 3099-3110, 2018.
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http://dx.doi.org/10.1002/jbm.a.36502DOI Listing
December 2018

Analysis and expression of the carotenoid biosynthesis genes from Deinococcus wulumuqiensis R12 in engineered Escherichia coli.

AMB Express 2018 Jun 2;8(1):94. Epub 2018 Jun 2.

School of Pharmaceutical Sciences, Nanjing Tech University, Nanjing, Jiangsu Province, China.

Deinococcus wulumuqiensis R12 is a red-pigmented extremophilic microorganism with powerful antioxidant properties that was isolated from radiation-contaminated soil in Xinjiang Uyghur Autonomous Region of China. The key carotenoid biosynthesis genes, crtE, crtB and crtI, which are related to the cells' antioxidant defense, were identified in the sequenced genome of R12 and analyzed. In order to improve the carotenoid yield in engineered Escherichia coli, the origin of carotenoid biosynthesis genes was discussed, and a strain containing the R12 carotenoid biosynthesis genes was constructed to produce lycopene, an important intermediate in carotenoid metabolism. The gene order and fermentation conditions, including the culture medium, temperature, and light, were optimized to obtain a genetically engineered strain with a high lycopene production capacity. The highest lycopene content was 688 mg L in strain IEB, which corresponds to a 2.2-fold improvement over the original recombinant strain EBI.
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http://dx.doi.org/10.1186/s13568-018-0624-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5984946PMC
June 2018

Resveratrol Suppresses Rotenone-induced Neurotoxicity Through Activation of SIRT1/Akt1 Signaling Pathway.

Anat Rec (Hoboken) 2018 06 20;301(6):1115-1125. Epub 2018 Feb 20.

Department of Anatomy, School of Basic Medical Sciences, Shandong University, Jinan, Shandong, 250012, China.

Rotenone is a common pesticide and has been reported as one of the risk factors for Parkinson disease. Rotenone can cause neuronal death or apoptosis through inducing oxidative injury and inhibiting mitochondrial function. As a natural polyphenolic compound, resveratrol possesses the antioxidant capacity and neuroprotective effect. However, the mechanism underlying the neuroprotective effect of resveratrol against rotenone-induced neurotoxicity remains elusive. Here, we treated PC12 cells with rotenone to induce neurotoxicity, and the neurotoxic cells were subjected to resveratrol treatment. The CCK8 and LDH activity assays demonstrated that resveratrol could suppress neurotoxicity induced by rotenone (P < 0.01). The DCFH-DA assay indicated that resveratrol reduced the production of reactive oxygen species (ROS). JC-1 and Hoechst 33342/PI staining revealed that resveratrol attenuated mitochondrial dysfunction and cell apoptosis. Moreover, resveratrol reversed rotenone-induced decrease in SIRT1 expression and Akt1 phosphorylation (P < 0.05). Furthermore, when the SIRT1 and Akt1 activity was inhibited by niacinamide and LY294002, respectively, the neuroprotective effect of resveratrol was remarkably attenuated, which implied that SIRT1 and Akt1 could mediate this process and may be potential molecular targets for intervening rotenone-induced neurotoxicity. In summary, our study demonstrated that resveratrol reduced rotenone-induced oxidative damage, which was partly mediated through activation of the SIRT1/Akt1 signaling pathway. Our study launched a promising avenue for the potential application of resveratrol as a neuroprotective therapeutic agent in Parkinson disease. Anat Rec, 301:1115-1125, 2018. © 2018 Wiley Periodicals, Inc.
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http://dx.doi.org/10.1002/ar.23781DOI Listing
June 2018

[Research progress in multi-enzyme regulation of genetically engineered bacteria producing lycopene].

Sheng Wu Gong Cheng Xue Bao 2017 Apr;33(4):552-564

College of Pharmacy, Nanjing Tech University, Nanjing 211816, Jiangsu, China.

Lycopene plays a crucial role in the biosynthesis pathway of 2-methyl-derythritol-4-phosphate (MEP) and mevalonic acid (MVA). It is a representative product of isoprenoid family, and a typical product of multi-enzyme catalytic reaction in organism. In this paper, we first introduced the general regulation methods in multi-enzyme synthesis reaction, including the construction of multi gene co-expression plasmid, gene order regulation, promoter and ribosome binding site regulation, gene knockout and replacement, aiming at the optimization strategies of multi-enzyme catalytic reaction in lycopene synthesis pathway. Meanwhile, we introduced several new regulation methods in multi-enzyme reaction, including multi-fragment assembly technology, artificial scaffold self-assembly methods and so on. At last, we summarized the application of these multi-enzyme regulation methods in lycopene synthesis. These methods provide a great inspiration and research foundation for the construction of lycopene-producing strains with high yield.
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http://dx.doi.org/10.13345/j.cjb.160324DOI Listing
April 2017

Cemental Tears: A Report of Four Cases and Literature Review.

Oral Health Prev Dent 2017;15(4):337-345

Purpose: To present four different cases with a diagnosed cemental tear. The differences in aetiology, clinical diagnosis and treatment of cemental tears are described and discussed in order to provide guidance for clinical practice.

Cases: Four patients of different ages presented with gingival swelling and other different complaints. Clinically, localised deep periodontal pockets and inflammation were noted on affected aspects in four cases. Radiographic examination revealed a prickly or flakey structure and bone loss on the affected side of the involved tooth. Different treatments, such as extraction, traditional periodontal initial therapy, periodontal flap surgery, or no clinical intervention were given based on different extents of tooth mobility and bone loss. In the first two cases, teeth with cemental tear were extracted due to poor prognosis. In case 3, deep pockets recovered to a normal condition, while cemental tears on the distal aspect of tooth 21 had no abnormal sensation or clinical symptoms. In case 4, a periapical radiograph showed distal bone loss was interrupted, and the tooth also recovered normal mobility. Histopathological evaluation of the specimens with H&E staining all resulted in a definitive diagnosis of cemental/cementodentinal tears.

Conclusions: Cementodentinal or cemental tears are unique, localized, tooth-related factors associated with attachment loss. Aging, trauma and occlusal overload are the main aetiological factors. Early diagnosis and appropriate treatment will avoid unnecessary tooth extraction and result in a better prognosis. Detailed clinical and radiographic examinations as well as explorative surgery may help to make a diagnosis of cemental tears, but histopathological analysis is the only method for a definitive diagnosis.
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http://dx.doi.org/10.3290/j.ohpd.a38745DOI Listing
January 2018

A lipase with broad solvent stability from Burkholderia cepacia RQ3: isolation, characteristics and application for chiral resolution of 1-phenylethanol.

Bioprocess Biosyst Eng 2016 Jan;39(1):59-66

Using both polar and low polar organic solvents (DMSO and toluene) as screening stress, a solvent-stable bacterium Burkholderia cepacia RQ3 was newly isolated. An organic solvent-stable lipase from strain RQ3 was purified in a single step with 50.1% recovery by hydrophobic chromatography. The purified lipase was homogenous on SDS-PAGE and had an apparent molecular mass of 33 kDa. The gene of lipase RQ3 with an open reading frame of 1095 bp encoding 364-amino acid residues was cloned. The optimal pH and temperature for lipase activity were 9.0 and 40 °C. The lipase was stable in a wide pH range of 6.0-10.0 and at temperature below 50 °C. Strikingly, all the tested hydrophilic and hydrophobic organic solvents significantly extended the half-life of lipase RQ3 compared with that in a solvent-free system, which indicated that lipase RQ3 showed a broad solvent tolerance to various organic solvents. The lipase demonstrated excellent enantioselective transesterification toward the (S)-1-phenylethanol with a theoretical conversion yield of 50% and ee p of 99.9%, which made it an exploitable biocatalyst for organic synthesis and pharmaceutical industries.
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http://dx.doi.org/10.1007/s00449-015-1489-1DOI Listing
January 2016
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