Enhancement of transglutaminase production in Streptomyces mobaraensis DSM 40587 by non-nutritional stress conditions: Effects of heat shock, alcohols, and salt treatments

Lili Zhang,Lanwei Zhang,Huaxi Yi,Ming Du,Yingchun Zhang,Xue Han,Zhen Feng,Jingyan Li,Yuehua Jiao,Yanhe Zhang,Chunfeng Guo 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.7

Stress-mediated bioprocess is a strategy designed to enhance biological target productivity. In this study,an attempt was made to enhance transglutaminase (TGase) production by Streptomyces mobaraensis by using different stress conditions including heat shock, alcohols and salt stress. Results showed that the effects of stress on TGase production depended on the type applied. For heat shock, TGase production (1.32 U/ml) was recorded maximum in the culture treated at 48 h post inoculation in water bath at 60 oC for 1 min. For alcohols treatment, the maximum activity of TGase (1.77 and 1.75 U/ml) was obtained when 3% methanol was added into the medium at 0 or 24 h of fermentation. However, a 3.5-fold increased production of TGase (3.8 U/ml) was observed in the medium supplemented with 0.2mol/l MgCl2 compared with the basic medium at the beginning of fermentation. In conclusion, TGase production from S. mobaraensis was improved by heat shock, methanol and salt stress treatments, MgCl2 stress was the most effective.

LAMP, PCR, and real-time PCR detection of Acetobacter aceti in yogurt

Wei Zhou,Yan Zhang,Shuang Wang,Yuehua Li,Jingjing Zhang,Cuixia Zhang,Zan Wang,Zhisheng Zhang 한국식품과학회 2017 Food Science and Biotechnology Vol.26 No.1

Acetic acid bacteria (AAB) can spoil food. Acetobacter aceti as a core subgroup of AAB is usually isolated from yogurt. A. aceti should be timely and effectively detected to prevent yogurt contamination. The present study focused on A. aceti to establish an assay that can be performed to detect AAB in yogurt. LAMP, PCR, and real-time PCR were applied and compared for detecting A. aceti from pure culture and artificially contaminated yogurt samples. In pure culture, LAMP showed the highest detection sensitivity with 10−1 CFU/mL. For yogurt samples, the sensitivity limit of LAMP was 102 CFU/mL, which was lower than that of real-time PCR (101 CFU/mL). The results indicated that these methods could be quickly and efficiently applied to detect A. aceti. As LAMP technology has low cost and high detection efficiency, it can potentially be applied for detecting A. aceti in production and quality control programs of yogurt.

Prevalence of Decreased Myocardial Blood Flow in Symptomatic Patients with Patent Coronary Stents: Insights from Low-Dose Dynamic CT Myocardial Perfusion Imaging

Yuehua Li,Mingyuan Yuan,Mengmeng Yu,Zhigang Lu,Chengxing Shen,Yining Wang,Bin Lu,Jiayin Zhang 대한영상의학회 2019 Korean Journal of Radiology Vol.20 No.4

Objective: To study the prevalence and clinical characteristics of decreased myocardial blood flow (MBF) quantified by dynamic computed tomography (CT) myocardial perfusion imaging (MPI) in symptomatic patients without in-stent restenosis. Materials and Methods: Thirty-seven (mean age, 71.3 ± 10 years; age range, 48–88 years; 31 males, 6 females) consecutive symptomatic patients with patent coronary stents and without obstructive de novo lesions were prospectively enrolled to undergo dynamic CT-MPI using a third-generation dual-source CT scanner. The shuttle-mode acquisition technique was used to image the complete left ventricle. A bolus of contrast media (50 mL; iopromide, 370 mg iodine/mL) was injected into the antecubital vein at a rate of 6 mL/s, followed by a 40-mL saline flush. The mean MBF value and other quantitative parameters were measured for each segment of both stented-vessel territories and reference territories. The MBFratio was defined as the ratio of the mean MBF value of the whole stent-vessel territory to that of the whole reference territory. An MBFratio of 0.85 was used as the cut-off value to distinguish hypoperfused from non-hypoperfused segments. Results: A total of 629 segments of 37 patients were ultimately included for analysis. The mean effective dose of dynamic CT-MPI was 3.1 ± 1.2 mSv (range, 1.7–6.3 mSv). The mean MBF of stent-vessel territories was decreased in 19 lesions and 81 segments. Compared to stent-vessel territories without hypoperfusion, the mean MBF and myocardial blood volume were markedly lower in hypoperfused stent-vessel territories (77.5 ± 16.6 mL/100 mL/min vs. 140.4 ± 24.1 mL/100 mL/min [p < 0.001] and 6.4 ± 3.7 mL/100 mL vs. 11.5 ± 4 mL/100 mL [p < 0.001, respectively]). Myocardial hypoperfusion in stentvessel territories was present in 48.6% (18/37) of patients. None of clinical parameters differed statistically significantly between hypoperfusion and non-hypoperfusion subgroups. Conclusion: Decreased MBF is commonly present in patients who are symptomatic after percutaneous coronary intervention, despite patent stents and can be detected by dynamic CT-MPI using a low radiation dose.

Study of the Non-Linearity on TiO2(0 0 1) Surface with Oxygen Defects: A First-Principles Study

Yuehua Dai,Xu Zhang,Chengzhi Ma,Zhiyong Pan,Feifei Wang,Wenjuan Lu,Jin Yang,Fei Yang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2017 NANO Vol.12 No.8

First-principles plane-wave pseudopotential calculations were performed to study the energetics and electronic structures of oxygen defects on rutile TiO2(0 0 1). The influence of the material thickness on non-linearity (NL) was studied. With the increase in the thickness, the NL became stronger. Calculating the site-projected density of states by applying an external electric field showed that the NL of the bulk is due to the exchange of electrons between O 2p orbitals and Ti 3d orbitals. Finally, the influence of oxygen defects—oxygen vacancies (Vo), oxygen interstitials (Oi), and oxygen vacancies/oxygen interstitial (Vo + Oi) pairs (Frenkel pair defects)—on the NL of TiO2 was studied. These results demonstrate that the band gap (Eg) of TiO2 became gradually narrower as the electric field increased. The Stark effect and defects can lead to the splitting of degenerate energy levels. Stronger electric fields increase the band splitting and reduce Eg. With the increase in the Vo concentration, the decrease in the splitting amplitude and width of the energy level lead to weakening of the transfer of electrons between O and Ti atoms and optimizing the NL of TiO2. Therefore, the incorporation of Vo plays a significant role in improving the NL of TiO2.

The Development and Application of Hierarchical Experimenting Platform for Embedded System Course

Kaisheng Zhang,Yuehua Li,Yao Gong 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.11

There are many disadvantages existing in the current experimenting platforms for embedded system course. Therefore, this paper has devised a hierarchical experimenting platform based on the CDIO education mode to improve both the teaching and learning experience. The experimenting platform devised in this paper is composed of a motherboard and several microprocessor plug-in boards. The motherboard can meet with various experimenting requirements by changing different plug-in boards. The demonstration source code is plug-in board independent, so the source code can be shared by different plug-in boards. The teaching practical shows that, this hierarchical experimenting platform can significantly improve the teaching and learning experience.

Preparation of b-Ca3(PO4)2 bioceramic powderfrom calcium carbonate and phosphoric acid q

Yun Zhang,Guangfu Yin,Shifu Zhu,Dali Zhou,Yuehua Wang,Yong Li,Lin Luo 한국물리학회 2005 Current Applied Physics Vol.5 No.5

When preparing b-tricalcium phosphate (b-TCP) with Ca(NO3)2 or Ca(OH)2 as the raw materials, because of the problem ofltering, it is dicult to industrialize traditional methods. In this paper,b-TCP was prepared with calcium carbonate and phospho-ric acid. According to XRD spectrum, the precursor of this system is octacalcium phosphate (OCP) [Ca8H2(PO4)6Æ5H2O] instead ofnon-stoichiometric hydroxyapatite (HA) obtained from traditional methods, and thermodynamics mechanism of the reaction wasalso studied. The crystalb-TCP powders were obtained after the precursor had been calcined at 8501150.C for 2 h. SEM imagesshowed that hardening could eliminate the reunion to a great extent, and obtain dispersiveb-TCP powders with a particle diameterbetween 0.5 and 2.0l m. The main advantages of this process over traditional methods are the fast reaction rate, the easy ltering,the ne particle size and the minimum impurity..

Calcification Remodeling Index Characterized by Cardiac CT as a Novel Parameter to Predict the Use of Rotational Atherectomy for Coronary Intervention of Lesions with Moderate to Severe Calcification

Mengmeng Yu,Yuehua Li,Wenbin Li,Zhigang Lu,Meng Wei,Jiayin Zhang 대한영상의학회 2017 Korean Journal of Radiology Vol.18 No.5

Objective: To assess the feasibility of calcification characterization by coronary computed tomography angiography (CCTA) to predict the use of rotational atherectomy (RA) for coronary intervention of lesions with moderate to severe calcification. Materials and Methods: Patients with calcified lesions treated by percutaneous coronary intervention (PCI) who underwent both CCTA and invasive coronary angiography were retrospectively included in this study. Calcification remodeling index was calculated as the ratio of the smallest vessel cross-sectional area of the lesion to the proximal reference luminal area. Other parameters such as calcium volume, regional Agatston score, calcification length, and involved calcium arc quadrant were also recorded. Results: A total of 223 patients with 241 calcified lesions were finally included. Lesions with RA tended to have larger calcium volume, higher regional Agatston score, more involved calcium arc quadrants, and significantly smaller calcification remodeling index than lesions without RA. Receiver operating characteristic curve analysis revealed that the best cutoff value of calcification remodeling index was 0.84 (area under curve = 0.847, p < 0.001). Calcification remodeling index ≤ 0.84 was the strongest independent predictor (odds ratio: 251.47, p < 0.001) for using RA. Conclusion: Calcification remodeling index was significantly correlated with the incidence of using RA to aid PCI. Calcification remodeling index ≤ 0.84 was the strongest independent predictor for using RA prior to stent implantation.

Synthesis of acetic acid-[(hydrazinylthioxomethyl)thio]-sodium and its application on the flotation separation of molybdenite from galena

Zhigang Yin,Wei Sun,Yuehua Hu,Runqing Liu,Wei Jiang,Chenhu Zhang,Qingjun Guan,Chenyang Zhang 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.52 No.-

A novel organic compound acetic acid-[(hydrazinylthioxomethyl)thio]-sodium was synthesized andcharacterized. Theflotation performance and adsorption mechanism of AHS to galena were investigatedby micro, benchflotation tests, UV spectra, zeta potential, FTIR and XPS measurements. The resultsdemonstrated that AHS exhibited superior depressing power to galena and could be used as selectivedepressant forflotation separation of molybdenite from galena. The results of UV spectra, FTIR, zetapotential and XPS measurements demonstrated that AHS chemisorb on galena surface by formingfivememberedcheat ring with releasing of H ions. Therefore, the possible adsorption mode of AHS on galenasurface was recommended.

Genetic Analysis and Serological Detection of Novel O-Antigen Gene Clusters of Plesiomonas shigelloides

( Xiaochen Wang ),( Daoyi Xi ),( Yuehua Li ),( Junxiang Yan ),( Jingyun Zhang ),( Xi Guo ),( Boyang Cao ) 한국미생물생명공학회(구 한국산업미생물학회) 2021 Journal of microbiology and biotechnology Vol.31 No.4

Plesiomonas shigelloides, a member of the family Vibrionaceae, is a gram-negative, rod-shaped, facultative anaerobic bacterium with flagella. P. shigelloides has been isolated from such sources as freshwater, surface water, and many wild and domestic animals. P. shigelloides contains 102 Oantigens and 51 H-antigens. The diversity of O-antigen gene clusters is relatively poorly understood. In addition to O1 and O17 reported by other laboratories, and the 12 O serogroups (O2, O10, O12, O23, O25, O26, O32, O33, O34, O66, O75, and O76) reported previously by us, in the present study, nine new P. shigelloides serogroups (O8, O17, O18, O37, O38, O39, O44, O45, and O61) were sequenced and annotated. The genes for the O-antigens of these nine groups are clustered together in the chromosome between rep and aqpZ. Only O38 possesses the wzm and wzt genes for the synthesis and translocation of O-antigens via the ATP-binding cassette (ABC) transporter pathway; the other eight use the Wzx/Wzy pathway. Phylogenetic analysis using wzx and wzy showed that both genes are diversified. Among the nine new P. shigelloides serogroups, eight use wzx/wzy genes as targets. In addition, we developed an O-antigen-specific PCR assay to detect these nine distinct serogroups with no cross reactions among them.

Natural History of Untreated Coronary Total Occlusions Revealed with Follow-Up Semi-Automated Quantitative Coronary CT Angiography: The Morphological Characteristics of Initial CT Predict Occlusion Shortening

Qian Wu,Mengmeng Yu,Yuehua Li,Wenbin Li,Zhigang Lu,Meng Wei,Jing Yan,Jiayin Zhang 대한영상의학회 2018 Korean Journal of Radiology Vol.19 No.2

Objective: To investigate the morphological changes of coronary chronic total occlusion (CTO) as determined by coronary computed tomography angiography (CCTA) follow-up using semi-automated quantitative analysis. Materials and Methods: Thirty patients with 31 CTO lesions confirmed by invasive coronary angiography and baseline/follow-up CCTA were retrospectively included. CTOs were quantitatively analyzed by a semi-automated coronary plaque analysis software (Coronary Plaque Analysis, version 2.0, Siemens) after manually determining the lesion border. Recanalized lumen was defined as the linear-like enhanced opacity traversing the non-opacified occluded segment. Other parameters, such as total occlusion length, total occlusion volume, volume with low attenuation component (< 30 Hounsfield unit [HU]), volume with middle to high attenuation component (30−190 HU) as well as the calcification volume, were also recorded. Results: Recanalized lumen was found within 48.4% (15/31) occlusions on the follow-up CCTA, compared to 45.2% (14/31) occlusions on the baseline CCTA. Eleven of 14 lesions (78.6%) with CT-visible recanalized lumen within CTOs had a shorter occlusion length on follow-up compared to only 3 of 17 lesions (17.6%) without CT-visible recanalized lumen (odds ratio, 17.1, p < 0.001). The percentage of low attenuation component of occlusions was smaller on follow-up CCTA compared to baseline value (18.1 ± 20.1% vs. 22.6 ± 19.6%, p = 0.033). Conclusion: Coronary computed tomography angiography enables non-invasive characterization of natural progression of untreated CTO lesions. Recanalized lumen within CTOs observed at baseline CCTA was associated with shortening of occlusion length on follow-up. Compared to their earlier stage, occlusions of later stage were presented with higher density of non-calcified components.