Construction of an Efficient Mutant Strain of Trichosporonoides oedocephalis with HOG1 Gene Deletion for Production of Erythritol

( Liangzhi Li ),( Tianyi Yang ),( Weiqiang Guo ),( Xin Ju ),( Cuiying Hu ),( Bingyu Tang ),( Jiaolong Fu ),( Jingsheng Gu ),( Haiyang Zhang ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.4

The mitogen-activated protein kinase HOG1 (high-osmolarity glycerol response pathway) plays a crucial role in the response of yeast to hyperosmotic shock. Trichosporonoides oedocephalis produces large amounts of polyols (e.g., erythritol and glycerol) in a culture medium. However, the effects of HOG1 gene knockout and environmental stress on the production of these polyols have not yet been studied. In this study, a To-HOG1 null mutation was constructed in T. oedocephalis using the loxP-Kan-loxP/Cre system as replacement of the targeted genes, and the resultant mutants showed much smaller colonies than the wild-type controls. Interestingly, compared with the wild-type strains, the results of shake-flask culture showed that To-HOG1 null mutation increased erythritol production by 1.44-fold while decreasing glycerol production by 71.23%. In addition, this study investigated the effects of citric acid stress on the T. oedocephalis HOG1 null mutants and the wild-type strain. When the supplementation of citric acid in the fermentation medium was controlled at 0.3% (w/v), the concentration of erythritol produced from the wild-type and To-HOG1 knockout mutant strains improved by 18.21% and 21.65%, respectively.

Enhancement of Ribitol Production during Fermentation of Trichosporonoides oedocephalis ATCC 16958 by Optimizing the Medium and Altering Agitation Strategies

Liangzhi Li,Huaxing Zhang,Jiaolong Fu,Chao Hu,Yayue Zheng,Yexian Qiu 한국생물공학회 2012 Biotechnology and Bioprocess Engineering Vol.17 No.2

To maximize the productivity of ribitol, which is an important starting material for the production of one expensive rare sugar, L-ribose, the effects of culture medium and agitation speed on cell growth as well as on the productivity of ribitol were thoroughly investigated in a 7 L fermentor. The maximum volumetric productivity,0.322 g/L/h of ribitol, were obtained at an initial glucose concentration of 200 g/L in a batch culture. Based on the optimum glucose concentration, the ribitol yield conversed from glucose was up to 0.193 g/g when 1% yeast extract was used as a nitrogen source. When the agitation speed was maintained at 200 rpm, the ribitol concentration of 38.60 g/L was collected after 120 h of cultivation time. Additionally, the scheme of two-phase agitation and glucose infusion was employed. To begin, in the first 24 h of fermentation, a high agitation rate at 350 rpm and the initial glucose concentration of 50 g/L were applied, and the biomass concentration of 25.50 g/L was achieved at 36 h of incubation; whereas this value was observed until 60 h in the former batch fermentation methods. Then, in the second phase, with the agitation speed reduced to 150 rpm and the infusion amount of glucose controlled at 150 g/L,the yield of ribitol reached to 65.00 g/L in two-phase agitation fermentation and was 1.68 fold of that obtained in one-stage batch fermentation. To our knowledge, this study first demonstrates its significant effectiveness in improving ribitol production with the application of Trichosporonoides oedocephalis ATCC 16958.

Resonance Elastic Scattering and Interference Effects Treatments in Subgroup Method

Li, Yunzhao,He, Qingming,Cao, Liangzhi,Wu, Hongchun,Zu, Tiejun Korean Nuclear Society 2016 Nuclear Engineering and Technology Vol.48 No.2

Based on the resonance integral (RI) tables produced by the NJOY program, the conventional subgroup method usually ignores both the resonance elastic scattering and the resonance interference effects. In this paper, on one hand, to correct the resonance elastic scattering effect, RI tables are regenerated by using the Monte Carlo code, OpenMC, which employs the Doppler broadening rejection correction method for the resonance elastic scattering. On the other hand, a fast resonance interference factor method is proposed to efficiently handle the resonance interference effect. Encouraging conclusions have been indicated by the numerical results. (1) For a hot full power pressurized water reactor fuel pin-cell, an error of about +200 percent mille could be introduced by neglecting the resonance elastic scattering effect. By contrast, the approach employed in this paper can eliminate the error. (2) The fast resonance interference factor method possesses higher precision and higher efficiency than the conventional Bondarenko iteration method. Correspondingly, if the fast resonance interference factor method proposed in this paper is employed, the $k_{inf}$ can be improved by ~100 percent mille with a speedup of about 4.56.

Homogenized cross-section generation for pebble-bed type high-temperature gas-cooled reactor using NECP-MCX

Qin Shuai,Li Yunzhao,He Qingming,Cao Liangzhi,Wang Yongping,Wu Yuxuan,Wu Hongchun 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.9

In the two-step analysis of Pebble-Bed type High-Temperature Gas-Cooled Reactor (PB-HTGR), the lattice physics calculation for the generation of homogenized cross-sections is based on the fuel pebble. However, the randomly-dispersed fuel particles in the fuel pebble introduce double heterogeneity and randomness. Compared to the deterministic method, the Monte Carlo method which is flexible in geometry modeling provides a high-fidelity treatment. Therefore, the Monte Carlo code NECP-MCX is extended in this study to perform the lattice physics calculation of the PB-HTGR. Firstly, the capability for the simulation of randomly-dispersed media, using the explicit modeling approach, is developed in NECP-MCX. Secondly, the capability for the generation of the homogenized cross-section is also developed in NECP-MCX. Finally, simplified PB-HTGR problems are calculated by a two-step neutronics analysis tool based on Monte Carlo homogenization. For the pebble beds mixed by fuel pebble and graphite pebble, the bias is less than 100 pcm when compared to the high-fidelity model, and the bias is increased to 269 pcm for pebble bed mixed by depleted fuel pebble. Numerical results show that the Monte Carlo lattice physics calculation for the two-step analysis of PB-HTGR is feasible.

Improvement of FK506 Production by Selection of 4-Aminobutyric Acid-tolerant Mutant and Optimization of its Fermentation Using Response Surface Methodology

Yang, Tianyi,Li, Jiaojiao,Li, Liangzhi,Zhang, Haiyang,Ma, Jing,Chen, Zhi,Hu, Cuiying,Ju, Xin,Fu, Jiaolong 한국응용생명화학회 2014 Applied Biological Chemistry (Appl Biol Chem) Vol.57 No.6

Tacrolimus (FK506), a 23-membered polyketide macrolide with immunosuppressant activity, can be produced by Streptomyces tsukubaensis. We studied a variety of mutant strains of S. tsukubaensis for the microbial production of FK506. The best strain (CZ-19) was obtained from the parent strain LLZ-1 by nitrosoguanidine mutation and 4-Aminobutyric acid (FK506 precursor structure analogs) adaption. In the shake-flask experiments, titer of FK506 by CZ-19 was 532.44 mg/L, increased by 65.13% compared to that of the parent strain. Through single factor experiments and response surface methodology, we further optimized the medium for improved FK506 production by CZ-19 in shake flask culture. The optimal medium for enhanced FK506 production was as follows: 17.19 g/L corn starch, 21.78 g/L glucose, 8.06 g/L peptone, and 18.98 mg/L 4-aminobutyric acid. The predicted FK506 titer was 906.49 mg/L, and the experimental data confirmed the validity of the model. The present study demonstrates that S. tsukubaensis CZ-19 is a promising strain for industrial production of FK506.

Epidemiologic characteristics and a prognostic nomogram for patients with vulvar cancer: results from the Surveillance, Epidemiology, and End Results (SEER) program in the United States, 1975 to 2016

Shiyuan Wei,Lu Li,Tingting Yi,Licong Su,Qi Gao,Liangzhi Wu,Zhenbo OuYang 대한부인종양학회 2023 Journal of Gynecologic Oncology Vol.34 No.6

Objective: To elucidate clinical characteristics and build a prognostic nomogram for patients with vulvar cancer. Methods: The study population was drawn from the Surveillance, Epidemiology, and End Results (SEER) database. Patients were randomly assigned to training and validation sets. Cox proportional hazards model and competing risk model were used to identify the prognostic parameters of overall survival (OS) and cancer-specific survival (CSS) to construct a nomogram. The nomogram was assessed by concordance index (C-index), area under the curve (AUC), calibration plot, and decision curve analysis (DCA). Results: A total of 20,716 patients were included in epidemiological analysis, of whom 7,025 patients were selected in survival analysis, including 4,215 and 2,810 in training and validation sets, respectively. The multivariate Cox model showed that the predictors for OS were age, marital status, histopathology, differentiation and tumor node metastasis (TNM) stages, whether to undergo surgery and chemotherapy. However, the predictors for CSS were age, race, differentiation and TNM stages, whether to undergo surgery and radiation. The C-index for OS and CSS in the training set were 0.76 and 0.80. The AUC in the training set for 1-, 3- and 5-year OS and CSS were 0.84, 0.81, 0.80 and 0.88, 0.85, 0.83, respectively, which was similar in the validation set. The calibration curves showed good agreement between prediction and actual observations. DCA revealed that the nomogram had a better discrimination than TNM stages. Conclusions: The nomogram showed accurate prognostic prediction in OS and CSS for vulvar cancer, which could provide guidance to clinical practice.

Improvement of FK506 Production by Selection of 4-Aminobutyric Acid-tolerant Mutant and Optimization of its Fermentation Using Response Surface Methodology

Tianyi Yang,Jiaojiao Li,Liangzhi Li,Haiyang Zhang,Jing Ma,Zhi Chen,Cuiying Hu,Xin Ju,Jiaolong Fu 한국응용생명화학회 2014 Applied Biological Chemistry (Appl Biol Chem) Vol.57 No.6

Tacrolimus (FK506), a 23-membered polyketidemacrolide with immunosuppressant activity, can be produced byStreptomyces tsukubaensis. We studied a variety of mutant strainsof S. tsukubaensis for the microbial production of FK506. Thebest strain (CZ-19) was obtained from the parent strain LLZ-1 bynitrosoguanidine mutation and 4-Aminobutyric acid (FK506precursor structure analogs) adaption. In the shake-flask experiments,titer of FK506 by CZ-19 was 532.44 mg/L, increased by 65.13%compared to that of the parent strain. Through single factorexperiments and response surface methodology, we furtheroptimized the medium for improved FK506 production by CZ-19in shake flask culture. The optimal medium for enhanced FK506production was as follows: 17.19 g/L corn starch, 21.78 g/Lglucose, 8.06 g/L peptone, and 18.98 mg/L 4-aminobutyric acid. The predicted FK506 titer was 906.49 mg/L, and the experimentaldata confirmed the validity of the model. The present studydemonstrates that S. tsukubaensis CZ-19 is a promising strain forindustrial production of FK506.

Sources, Components, Structure, Catalytic Mechanism and Applications: a Critical Review on Nicotinate Dehydrogenase

Chen Zhi,Xu Xiangjing,Ju Xin,Yan Lishi,Li Liangzhi,Yang Lin 한국미생물·생명공학회 2023 Journal of microbiology and biotechnology Vol.33 No.6

Plant-derived insecticide-neonicotinoid insecticides (NIs) played a crucial role in the development of agriculture and food industry in recent years. Nevertheless, synthesis of these nitrogen-containing heterocyclic compounds with an effective and greener routing remains challenging especially to the notion raise of “green chemistry” and “atom economy”. While bio-catalyzed methods mediated by nicotinate dehydrogenase (NDHase) then provide an alternative. The current review mainly focuses on the introduction of sources, components, structure, catalytic mechanism and applications of NDHase. Specifically, NDHase is known as nicotinic acid hydroxylase and the sources principally derived from phylum Proteobacteria. In addition, NDHase requires the participation of the electron respiratory chain system on the cell membrane. And the most important components of the electron respiratory chain are hydrogen carrier, which is mainly composed of iron-sulfur proteins (Fe-S), flavin dehydrogenase (FAD), molybdenum binding protein and cytochromes. Heterologous expression studies were hampered by the plasmid and host with high efficiency and currently only Pseudomonas entomophila L48 as well as Comamonas testosterone was successfully utilized for the expression of NDHase. Furthermore, it is speculated that the conjugate and inductive effects of the substituent group at position 3 of the substrate pyridine ring exerts a critical role in the hydroxylation reactions at position 6 concerning about the substrate molecular recognition mechanism. Finally, applications of NDHase are addressed in terms of pesticide industry and wastewater treatment. On conclusion, this critical review would not only deepen our understanding of the theory about NDHase, but also provides the guideline for future investigation of NDHase.

SNPs in the coding region of bovine MGAT2 gene are associated with body weight and weight gain

Lian Qu,Mingjuan Yang,Jinlong Zhu,Junxia Liu,Mijie Li,Liangzhi Zhang,Xianyong Lan,Chuzhao Lei,Chunlei Zhang,Hong Chen 한국유전학회 2011 Genes & Genomics Vol.33 No.3

Monoacylglycerol acyltransferase 2 (MGAT2), as a candidate gene for quantitative traits, relates to dietary fat uptake, lipids synthesis and storage, which plays a major role in the absorption of dietary fat by catalyzing the resynthesis of triacylglycerol in enterocytes. In this study, based on DNA pool sequencing and PCR‐RFLP methods, polymorphisms of the MGAT2 gene were detected in 1145 Chinese indigenous cattle. The results revealed two novel mutations located on exon 1and exon 5 (NM_001099136.1:m.84G>T and 756A>G). Hence, we described the HaeIII forced PCR–RFLP method in exon1 and a MluI PCR–RFLP method in exon5 to detect them. In addition, the associations of these polymorphisms with growth traits were evaluated in Nanyang cattle. The results showed that only HaeIII locus was associated with body weight and average daily gain aged 6 months, and individuals with genotype TT showed significantly higher body weight and average daily gain than those with genotype GG.

Calculation of thermal neutron scattering data of MgF2 and its effect on beam shaping assembly for BNCT

Hu Jiaqi,Qiao Zhaopeng,Fan Lunhe,Tang Yongqiang,Cao Liangzhi,Zu Tiejun,He Qingming,Li Zhifeng,Wang Sheng 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.4

MgF2 as a moderator material has been extensively used in the beam shaping assembly (BSA) that plays an important role in the boron neutron capture therapy (BNCT). Regarded as important for applications, the thermal neutron scattering data of MgF2 were calculated, based on the phonon expansion model. The structural properties of MgF2 were researched by the VASP code based on the ab-initio methods. The PHONOPY code was employed to calculate the phonon density of states. Furthermore, the NJOY code was used to calculate the thermal neutron scattering data of MgF2. The calculated inelastic cross sections plus absorption cross sections are in agreement with the available experimental data. The neutron transport in the BSA has been simulated by using a hybrid Monte-Carlo-Deterministic code NECP-MCX. The results indicated that compared with the calculation of the free gas model, the thermal neutron flux and epithermal neutron flux at the BSA exit port calculated by using the thermal neutron scattering data of MgF2 were reduced by 27.7% and 8.2%, respectively.