Enhanced performance of the methylerythritol phosphate pathway by manipulation of redox reactions relevant to IspC, IspG, and IspH

Zhou, Jia,Yang, Liyang,Wang, Chonglong,Choi, Eui-Sung,Kim, Seon-Won Elsevier 2017 Journal of biotechnology Vol.248 No.-

<P>The 2C-methyl-D-erythritol 4-phosphate (MEP) pathway is a carbon-efficient route for synthesis of isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP), the building blocks of isoprenoids. However, practical application of a native or recombinant MEP pathway for the mass production of isoprenoids in Escherichia coli has been unsatisfactory. In this study, the entire recombinant MEP pathway was established with plasmids and used for the production of an isoprenoid, protoilludene. E. coli harboring the recombinant MEP pathway plasmid (ME) and a protoilludene synthesis pathway plasmid (AO) produced 10.4 mg/L of protoilludene after 48 h of culture. To determine the rate-limiting gene on plasmid ME, each constituent gene of the MEP pathway was additionally overexpressed on the plasmid AO. The additional overexpression of IPP isomerase (IDI) enhanced protoilludene production to 67.4 mg/L. Overexpression of the Fpr and FIdA protein complex, which could mediate electron transfer from NADPH to Fe-S cluster proteins such as IspG and IspH of the MEP pathway, increased protoilludene production to 318.8 mg/L. Given that it is required for IspC as well as IspG/H, the MEP pathway has high demand for NADPH. To increase the supply of NADPH, a NADH kinase from Saccharomyces cerevisiae (tPos5p) that converts NADH to NADPH was introduced along with the deletion of a promiscuous NADPH-dependent aldehyde reductase (YjgB) that consumes NADPH. This resulted in a protoilludene production of 512.7 mg/L. The results indicate that IDI, Fpr-FIdA redox proteins, and NADPH regenerators are key engineering points for boosting the metabolic flux toward a recombinant MEP pathway. (C) 2017 Elsevier B.V. All rights reserved.</P>

Combinatorial Engineering of Hybrid Mevalonate Pathways in Escherichia coli for Protoilludene Production

Liyang YANG,Chonglong WANG,Jia ZHOU,Jung-Hun KIM,Seon-Won KIM 한국생물공학회 2014 한국생물공학회 학술대회 Vol.2014 No.10

Opportunities and Challenges of in vitro Synthetic Biosystem for Terpenoids Production

Yang Liyang,Gong Qiang,Lv Jifang,Zhou Bangyuan,Li Guilan,Guo JianQuan 한국생물공학회 2022 Biotechnology and Bioprocess Engineering Vol.27 No.5

Terpenoids are a large variety of natural products with remarkable diverse biological functions, and have a wide range of applications in flavors, pharmaceuticals, biofuels, pigments, and so on. However, limited production of terpenoids from natural resources constrains their use of bulk commodity products. In vivo synthetic biosystem, harnessing living organisms to produce terpenoids, has been broadly used and in-depth reviewed for terpenoids production, which has inherent weaknesses, such as slow reaction rate, low product yield, toxic intermediates, and high separation cost. In vitro synthetic biosystem, harboring numerous enzymes and/or coenzymes assembled into an in vitro enzymatic bioreactions, can obviate part of problems associated with in vivo style. In this review, the general design of in vitro synthetic biosystem is presented with seven supporting examples: mevalonate, isoprene, limonene, pinene, farnesene, amorpha-4,11-diene and taxadiene. The efforts for the large-scale implementation of in vitro synthetic biosystem have been addressed to enzymes engineering, computational modeling and cofactors recycle. The review also discusses the challenges and solutions for the largescale implementation of in vitro synthetic biosystem around enzymes stability and cofactors recycle. This review may suggest in vitro synthetic biosystems become a realistic option for the production of diverse valuable terpenoids, even expand to other commodity chemicals.

The complete mitochondrial genome of parasitoid wasp Pseudoligosita yasumatsui (Hymenoptera: Trichogrammatidae) and its phylogenetic implications

Wang Liyang,Wu Hongxuan,He Wei,Zhou Qiang 한국응용곤충학회 2023 Journal of Asia-Pacific Entomology Vol.26 No.4

Pseudoligosita yasumatsui (Viggiani and Rao, 1978) (Hymenoptera: Trichogrammatidae) is an egg parasitoid wasp that preys on rice planthoppers, one of the most significant pests in Asian rice-growing regions. An enriched mitochondrial genome database of rice planthopper egg parasitoids is the basis for phylogenetic analysis. Therefore, the complete mitochondrial genome of P. yasumatsui was sequenced using NGS sequencing. The total length of the mitochondrial genome of P. yasumatsui is 16,036 bp, containing 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), two ribosomal RNA genes (rRNAs) and a control region (CR). The mitochondrial genome showed a negative AT skew (-0.09) and a positive GC skew (0.19). Thirteen PCGs all started with ATN codons and ended with TAA. All 22 tRNAs have a typical cloverleaf structure. A comparison with the presumed arthropod ancestral mitochondrial genome using CREx web serve observed a large number of tRNAs as well as PCGs inversions, rearrangements, and inversion reversals of large gene segments (trnE-rrnL). Based on the Bayesian inference (BI) and maximum likelihood (ML) phylogenetic tree of P. yasumatsui and other 14 mito chondrial genomes from the Chalcidoidea superfamily, the phylogenetic relationship of P. yasumatsui within the Trichogrammatidae family was found to be ((Pseudoligosita + Megaphragma) + Trichogamma), and the phylo genetic relationship of five families was (Mymaridae + (Trichogrammatidae + (Aphelinidae + (Eulophidae + Pteromalidae)))). The close relationship between Pseudoligosita and Megaphragma as sister groups was suggested, and the data provide support for the monophyly of Oligositini.

Influence of Wet-Dry Cycles on Uniaxial Compression Behavior of Fissured Loess Disturbed by Vibratory Loads

Jian Xu,Liyang Zhou,Ke Hu,Yanfeng Li,Xiangang Zhou,Songhe Wang 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.5

In this study, the influence of wet-dry cycles on the uniaxial compression behavior of fissured loess after vibration was investigated by small shaking table tests, wet-dry tests, and uniaxial compression tests. Results show that the initial elastic modulus and peak strength both decline after wet-dry cycles while the morphology of stress-strain curves shows insignificant changes. Except for samples with a fissure angle α = 45°, where the bimodal stress-strain curves were observed, all show softening trend. The failure mode can be classified into four main types: fracture failure (α = 0° and 15°), slip-fracture coupled failure (α = 45°), slip failure (α = 60°), and compression shear failure (α = 30° and 90°). The failure modes of samples at α = 0°, 15°, 45°, and 60° are independent of wet-dry cycles but strongly depend on fissure angle, while those at the other fissure angles are more susceptible to wet-dry cycles. The uniaxial compressive strength (UCS) of fissured loess samples before vibration are greater than those after vibration. The relationship between UCS and fissure angle before and after vibration show double-valley pattern. A binary medium model for fissured loess considering vibration and wet-dry cycles was constructed, which was verified by test data.

Electrostatic spraying of membrane electrode for proton exchange membrane fuel cell

Ruiliang Liu,Wei Zhou,Liyang Wan,Pengyang Zhang,Shuangli Li,Yu Gao,Dongsheng Xu,Congcong Zheng,Mingfeng Shang 한국물리학회 2020 Current Applied Physics Vol.20 No.1

In order to improve the performance of proton exchange membrane fuel cell (PEMFC), the optimization of electrostatic spraying of membrane electrode was conducted. The influence of the spraying voltage on morphology, elemental composition of catalyst layer, and performance of the PEMFC were investigated. The results show that increasing spraying voltage could reduce agglomeration of the carbon-supported platinum particles, leading to more uniform pore distribution. High voltage did not accelerate oxidation of platinum catalyst. A high electrochemical active surface area of 26.18m2/gpt was obtained when the platinum-carbon catalyst layer was deposited in cone jet mode. With further increasing spraying voltage, the total ohmic resistance and catalytic activity were changed slightly, whereas the charge transfer resistance was increased. Using the optimized electrostatic spraying parameters (injection rate=100 μL min−1, spraying voltage=8.5 kV, and working distance= 12 mm), a peak power density of 1.408Wcm−2 was obtained with an output voltage of 0.451 V.

Blending of Soybean Oil with Selected Vegetable Oils: Impact on Oxidative Stability and Radical Scavenging Activity

Li, Yang,Ma, Wen-Jun,Qi, Bao-Kun,Rokayya, Sami,Li, Dan,Wang, Jing,Feng, Hong-Xia,Sui, Xiao-Nan,Jiang, Lian-Zhou Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.6

Background: Soybean oil may protect against cancer of the breast and prostate. It may also exert beneficial influence in combination with other oils. Here, blends (20%, v/v) of sea buckthorn oil (SEBO), camellia oil (CAO), rice bran oil (RBO), sesame oil (SEO) and peanut oil (PEO) with soybean oil (SBO) were formulated. Materials and Methods: Oxidative stability (OS) and radical scavenging activity (RSA) of SBO and blends stored under oxidative conditions ($60^{\circ}C$) for 24 days were studied. By blending with different kinds oils, levels of polyunsaturated fatty acids (PUFA) decreased, while monounsaturated fatty acid (MUFA) content increased. Progression of oxidation was followed by measuring peroxide value (PV), p-anisidine (PAV), conjugated dienes (CD) and conjugated trienes (CT). Results: Inverse relationships were noted between PV and OS at termination of storage. Levels of CD and CT in SBO, and blends, increased with increase in time. The impact of SEO as additives on SBO oxidation was the strongest followed by RBO, CAO, SEBO and PNO. Conclusions: Oxidative stability of oil blends was better than SBO, most likely as a consequence of changes in fatty acids and tocopherols' profile, and minor bioactive lipids found in selected oils. The results suggest that these oil blends could contribute as sources of important antioxidant related to the prevention of chronic diseases associated to oxidative stress, such as in cancer and coronary artery disease.

Shear-strain induced structural relaxation of Cu Σ3 [110](112) symmetric tilt grain boundary: The role of foreign atoms and temperature

Li Yang,Xue Hongtao,Zhou Xin,Tang Fuling,Li Xiuyan,Ren Junqiang,Lu Xuefeng 한국물리학회 2021 Current Applied Physics Vol.28 No.-

Grain boundaries (GBs) relaxation is a promising and effective strategy to improving GB stability or stabilizing nanocrystalline metals. However, previous studies mainly focused on nanocrystalline pure metals and GB behaviors therein, without considering the role of foreign atoms such as impurity or alloying atoms in GB relaxation. In this work, the shear-strain induced structural relaxation of pure Cu Σ3 [110](112) symmetric tilt GBs (STGBs), and the effects of foreign elements (Fe and Ni) and temperature on the GB relaxation were investigated in detail by molecular dynamics method. The results show that shear strain can trigger the structural relaxation of pure, Fe- and Ni-containing Cu GBs by the emission of Shockley partial dislocations from Cu GBs. Both Fe and Ni have impediment effects on the shear-strain induced GB relaxation, though the content of Fe or Ni atom (0.00165 at.%) is quite low in the GB model. The temperature cannot trigger GB relaxation independently within the considered temperature range, but play a positive role in the shear-strain induced structural relaxations of pure, Fe- and Ni-containing Cu Σ3 [110](112) STGBs. Our work might gain new insights into the mechanically induced GB relaxation in nanocrystalline copper and could be beneficial for improving the stability of Cu GBs.