Elucidating Bottlenecks to the Efficient Preparation of AB₅-Hexamer Mucosal Adjuvant Protein LTm by Genetic Engineering

( Di Liu ),( Fabiao Hu ),( Wenpeng Wang ),( Dong Wu ),( Xiujuan He ),( Wenyun Zheng ),( Haipeng Liu ),( Xingyuan Ma ) 한국미생물생명공학회(구 한국산업미생물학회) 2017 Journal of microbiology and biotechnology Vol.27 No.8

Escherichia coli heat-labile enterotoxin (LT) and its non-toxic mutant (LTm) are well-known powerful mucosal adjuvants and immunogens. However, the yields of these adjuvants from genetically engineered strains remain at extremely low levels, thereby hindering their extensive application in fundamental and clinical research. Therefore, efficient production of these adjuvant proteins from genetically engineered microbes is a huge challenge in the field of molecular biology. In order to explore the expression bottlenecks of LTm in E. coli, we constructed a series of recombinant plasmids based on various considerations and gene expression strategies. After comparing the protein expression among strains containing different recombinant plasmids, the signal sequence was found to be critical for the expression of LTm and its subunits. When the signal sequence was present, the strong hydrophobicity and instability of this amino acid sequence greatly restricted the generation of subunits. However, when the signal sequence was removed, abundantly expressed subunits formed inactive inclusion bodies that could not be assembled into the hexameric native form, although the inclusion body subunits could be refolded and the biological activity recovered in vitro. Therefore, the dilemma choice of signal sequence formed bottlenecks in the expression of LTm. These results reveal the expression bottlenecks of LTm, provide guidance for the preparation of LTm and its subunits, and certainly help to promote efficient preparation of this mucosal adjuvant protein.

Value of Exhaled Nitric Oxide and FEF25–75 in Identifying Factors Associated With Chronic Cough in Allergic Rhinitis

Xiaofang Liu,Xiangdong Wang,Xiujuan Yao,Yuhong Wang,Yongchang Sun,Luo Zhang 대한천식알레르기학회 2019 Allergy, Asthma & Immunology Research Vol.11 No.6

Purpose: Chronic cough in allergic rhinitis (AR) patients is common with multiple etiologies including cough variant asthma (CVA), non-asthmatic eosinophilic bronchitis (NAEB), gastroesophageal reflux-related cough (GERC), and upper airway cough syndrome (UACS). Practical indicators that distinguish these categories are lacking. We aimed to explore the diagnostic value of the fraction of exhaled nitric oxide (FeNO) and forced expiratory flow at 25% and 75% of pulmonary volume (FEF25–75) in specifically identifying CVA and NAEB in these patients. Methods: Consecutive AR patients with chronic cough were screened and underwent induced sputum, FeNO, nasal nitric oxide, spirometry, and methacholine bronchial provocation testing. All patients also completed gastroesophageal reflux disease questionnaires. Results: Among 1,680 AR patients, 324 (19.3%) were identified with chronic cough, of whom 316 (97.5%) underwent etiology analyses. Overall, 87 (27.5%) patients had chronic cough caused by NAEB, 78 (24.7%) by CVA, 16 (5.1%) by GERC, and 81 (25.6%) by UACS. Patients with either NAEB or CVA (n = 165, in total) were further assigned to a common group designated as CVA/NAEB, because they both responded to corticosteroid therapy. Receiver operating characteristic curves of FeNO revealed obvious differences among CVA, NAEB, and CVA/NAEB (area under the curve = 0.855, 0.699, and 0.923, respectively). The cutoff values of FeNO at 43.5 and 32.5 ppb were shown to best differentiate CVA and CVA/NAEB, respectively. FEF25–75 was significantly lower in patients with CVA than in those with other causes. A FEF25–75 value of 74.6% showed good sensitivity and specificity for identifying patients with CVA. Conclusions: NAEB, CVA, and UACS are common causes of chronic cough in patients with AR. FeNO can first be used to discriminate patients with CVA/NAEB, then FEF25–75 (or combined with FeNO) can further discriminate patients with CVA from those with CVA/NAEB.

Recent advances on Pestalotiopsis genus: chemistry, biological activities, structure–activity relationship, and biosynthesis

Peng Jiang,Xiujuan Fu,Hong Niu,Siwei Chen,Feifei Liu,Yu Luo,Dan Zhang,Hui Lei 대한약학회 2023 Archives of Pharmacal Research Vol.46 No.6

Strains of the fungal genus Pestalotiopsis are reported as large promising sources of structurally varied biologically active metabolites. Many bioactive secondary metabolites with diverse structural features have been derived from Pestalotiopsis. Moreover, some of these compounds can potentially be developed into lead compounds. Herein, we have systematically reviewed the chemical constituents and bioactivities of the fungal genus Pestalotiopsis, covering a period ranging from January 2016 to December 2022. As many as 307 compounds, including terpenoids, coumarins, lactones, polyketides, and alkaloids, were isolated during this period. Furthermore, for the benefit of readers, the biosynthesis and potential medicinal value of these new compounds are also discussed in this review. Finally, the perspectives and directions for future research and the potential applications of the new compounds are summarized in various tables.

Detecting Malicious Social Robots with Generative Adversarial Networks

( Bin Wu ),( Le Liu ),( Zhengge Dai ),( Xiujuan Wang ),( Kangfeng Zheng ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.11

Malicious social robots, which are disseminators of malicious information on social networks, seriously affect information security and network environments. The detection of malicious social robots is a hot topic and a significant concern for researchers. A method based on classification has been widely used for social robot detection. However, this method of classification is limited by an unbalanced data set in which legitimate, negative samples outnumber malicious robots (positive samples), which leads to unsatisfactory detection results. This paper proposes the use of generative adversarial networks (GANs) to extend the unbalanced data sets before training classifiers to improve the detection of social robots. Five popular oversampling algorithms were compared in the experiments, and the effects of imbalance degree and the expansion ratio of the original data on oversampling were studied. The experimental results showed that the proposed method achieved better detection performance compared with other algorithms in terms of the F1 measure. The GAN method also performed well when the imbalance degree was smaller than 15%.

RPK118, a PX Domain-containing Protein, Interacts with Peroxiredoxin-3 through Pseudo-Kinase Domains

Long Yu,Lingling Liu,Chenyi Yang,Jian Yuan,Xiujuan Chen,Jianing Xu,Youheng Wei,Jingchun Yang,Gang Lin 한국분자세포생물학회 2005 Molecules and cells Vol.19 No.1

RPK118 is a sphingosine kinase-1-binding protein that has been implicated in sphingosine 1 phosphate-mediated signaling. It contains a PX (phox homology) domain and two pseudo-kinase domains, and co-localizes with sphingosine kinase-1 on early endosomes. In this study we identified a novel RPK118-binding protein, PRDX3 (peroxiredoxin-3), by yeast two-hybrid screening. The interaction between these proteins was confirmed by pull-down assays and co-immunoprecipitation experi-ments. Deletion studies showed that RPK118 inter-acted with PRDX3 through its pseudokinase domains, and with early endosomes through its PX domain. Dou-ble immunofluorescence experiments demonstrated that PRDX3 co-localized with RPK118 on early endosomes in COS7 cells. PRDX3 is a member of the antioxidant family of proteins synthesized in the cytoplasm and functioning in mitochondria. Our findings indicate that RPK118 is a PRDX3-binding protein that may be involved in transporting PRDX3 from the cytoplasm to its mitochondrial site of function or to other mem-brane structures via endosome trafficking

The Benefits of Indirect Exposure to Trauma

Xiaofei Kang,Yueyan Fang,Sihan Li,Yadong Liu,Di Zhao,Xiujuan Feng,Yaqi Wang,Ping Li 대한신경정신의학회 2018 PSYCHIATRY INVESTIGATION Vol.15 No.5

Objective Ambulance personnel who witness trauma experienced by patients have been reported to experience positive changes, known as vicarious posttraumatic growth (VPTG). We examined VPTG and its relationship with social support and resilience among ambulance personnel. Methods The sample (n=227) was recruited from six emergency centers in China. The measures included the Posttraumatic Growth Inventory (PTGI), the Social Support Rating Scale (SSRS), and the 10-item Connor-Davidson Resilience Scale (CD-RISC-10). Structure Equation Modeling (SEM) and the bootstrapping procedure were used to examine indirect effects. Results The participants’ mean score for VPTG was 68.96 (SD=15.51). Social support had significant direct effects on resilience (β=0.51, p<0.001) and VPTG (β=0.25, p=0.001), and resilience (β=0.58, p<0.001) had a significant direct effect on VPTG. Furthermore, social support had a significant indirect effect (0.51×0.58=0.30, p<0.001) on VPTG through resilience. Conclusion Although the nature of the work of ambulance personnel is not expected to change, the negative effects of the trauma they encounter can be reduced by providing them with more support resources and interventions to foster their resilience, which in turn, promote VPTG.

Heterogeneous amino acid-based tungstophosphoric acids as efficient and recyclable catalysts for selective oxidation of benzyl alcohol

Xiaoxiang Han,Yingying Kuang,Chunhua Xiong,Xiujuan Tang,Qing Chen,Chin-Te Hung,Li-Li Liu,Shang-Bin Liu 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.7

A series of organic-inorganic composite catalysts, prepared by modifying tungstophosphoric acid (TPA; H3PW12O40) with different amino acids such as phenylalanine (Phe), alanine (Ala), and glycine (Gly) were synthesized. The physicochemical and acidic properties of these (MH)xH3−xPW12O40 (M=Phe, Ala, and Gly; x=1-3) composite materials were characterized by a variety of different analytical and spectroscopic techniques, namely TGA, XRD, FTIR, XPS, and NMR, and exploited as heterogeneous catalysts for selective oxidation of benzyl alcohol (BzOH) with hydrogen peroxide (H2O2). Among them, the [PheH]H2PW12O40 catalyst exhibited the best oxidative activity with an excellent BzOH conversion of 99.0% and a desirable benzaldehyde (BzH) selectivity of 99.6%. Further kinetic studies and model analysis by response surface methodology (RSM) revealed that the oxidation of BzOH with H2O2 follows a second-order reaction with an activation energy of 56.7 kJ·mol−1 under optimized experimental variables: BzOH/H2O2 molar ratio=1 : 1.5mol/mol, amount of catalyst=6.1 wt%, reaction time (x3)=3.8 h, and amount of water (x4)=30.2mL.

An Improved Thermal Conductivity Model for Unsaturated Clay

Xinye Song,Henghui Fan,Jiawei Liu,Xiujuan Yang 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.8

The thermal properties of soils vary because of the different textures of soils; thus, it is valuable to conduct research on the development of thermal conductivity models for soils with different textures. Clay samples with different dry densities and increasing incremental water contents were prepared, their thermal conductivities were measured by the transient plane source (TPS) method. The experimental results show that the thermal conductivity of clay increases with increasing water content and dry density. The water content has a stronger influence than the dry density on the thermal conductivity. This paper presents an improved model to predict the thermal conductivity of unsaturated clay. The model considers the different contributions of minerals in the soil and the distribution of water and air in pores. The accuracy of the model is verified by soil thermal conductivity data that was previously measured and collected from ten regions. Compared with the three similar models proposed in the literature, the new model proposed in this paper has a higher degree of correlation to describe the thermal conductivity of clay.

Deep-blue organic light-emitting diodes based on multi-tert-butyl modified naphthylene

Bin Wei,Hanfei Xu,Ning Zhao,Xicun Gao,Yiteng Ye,Yingnan Wang,Dengli Yao,Xiao-Wen Zhang,Xiujuan Liu 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.102 No.-

Six tert-butyls modified naphthyl derivative (2,6-di-tert-butyl-1,5-bis-(3,5-di-tert-butyl-phenyl)-naphthalene (N(dtb)4) was synthesized and tested for host and guest materials in organic light-emittingdiodes (OLEDs). Blue OLED using N(dtb)4 as a host and an emitter DSA-PH as a guest reaches an efficiencyof 11.52 cd A 1 (maximum external quantum efficiency 7.8 % and maximum power efficiency10.33 lm W 1). In addition, for the OLED with N(dtb)4 being a guest, we find that the concentrations ofN(dtb)4 will also affect the performance of the OLED, among which ADN: 5 wt.% N(dtb)4 has higher efficiency,and the maximum current efficiency, external quantum efficiency (EQE) and power efficiency ofthe device reach 3.75 cd A 1, 3.93 % and 3.36 lm W 1, respectively. We also investigated the pure N(dtb)4-based ultraviolet OLED (UV-OLED), and achieved the maximum EQE of the device is 1.12 %. These resultsindicate that N(dtb)4, a novel synthesized fluorescent organic material, has great potential applications inOLEDs and accordingly advancing lightings and displays.