1.Construction, Screening and Antibody Structure Homology Modeling of Phage Single Chain Variable Fragment Library Against Ofloxacin
Xiuyuan ZHANG ; Kuo HE ; Xinjun DU ; Junping WANG ; Qing YANG
Chinese Journal of Analytical Chemistry 2014;(6):829-834
To construct a library of mouse single chain variable fragment (scFv) antibody against ofloxacin using phage display and recombinant antibody technique, specific anti-ofloxacin scFv was screened and 3D structure was homology modeling. Total RNA was extracted from hybridoma cell of ofloxacin mAb, and was used to amplify VH and VL gene by RT-PCR using random primer. Then they were linked by a DNA linker encoding (G1y4 Ser) 3 as VH-linker-VL sequence forming scFv by SOE(splicing by overlap extension) PCR. These fragments were inserted into phage T7 after double digestion and transformed with host bacteria BLT5403. 3 ×105 pfu / ml single chain antibody phage libraries were successfully constructed. Four positive phage scFv clones were screened by direct competitive ELISA after four times of enriched procedure in the order of adsorption-elution-amplificatio, 3D structure of specific scFv was homology modeling finally. This research lays a foundation for further massive expression of anti-ofloxacin scFv.
2.Inhibitory effects of blocking voltage-dependent potassium channel 1.3 on human monocyte-derived macrophage differentiation into foam cells
Xinjun LEI ; Aiqun MA ; Yutao XI ; Wei ZHANG ; Yan YAO ; Yuan DU
Journal of Peking University(Health Sciences) 2006;38(3):257-261
Objective: To investigate the expression of voltage-dependent potassium channel 1.3(Kv1.3) mRNA and protein during human monocyte-derived macrophage differentiation into foam cells and its function in foam cell formation. Methods: Human peripheral blood monocytes were isolated from healthy male volunteers by density gradient centrifugation and then by adherent method. The obtained monocytes were cultured for 5 days to differentiate into macrophages. Based on establishment of the human macrophage-derived foam cell model, the expression of Kv1.3 channel was investigated by immunocytochemical staining, reverse transcription-polymerase chain raction (RT-PCR) and Western blot. Furthermore, the effects of rMargatoxin, a Kv 1.3 channel-specific inhibitor, on cholesterol metabolism in macrophages incepting oxidized low density lipoprotein (OxLDL) were studied. Results: After the macrophages co-incubated with 30 mg/L OxLDL at 37 ℃ for 60 hours, the cellular volume obviously enlarged and many red lipid granules were deposited in cytoplasm. The total amount of cholesterol (TC),free cholesterol ( FC ) and cholesterol ester ( CE ) in cells markedly increased and the ratio of CE/TC rose from ( 14.4±6.8) % to (57.9±3.5) % (n=7,P<0.05). However, the expression of Kv1.3 channel had no significant change. r Margatoxin (0.1 nmol/L and 10 nmol/L) markedly reduced the contents of TC, FC and CE in macrophages and the ratios of CE/TC decreased to (42.8±11.6) % and (22.6±8.0)% , respectively (n=7, P<0.05). Meanwhile, the red lipid granules deposited in the cytoplasm of macrophages also decreased. Conclusion: These data clearly show that the expression of Ky1.3 channel does not change obviously during human monocyte-derived macrophage differentiation into foam cells and the blocking of it would prevent foam cell formation.
3.Molecular cloning, recombinant expression and characterization of lysozyme from Chinese shrimp Fenneropenaeus chinensis.
Xingjiang BU ; Xinjun DU ; Wenjie ZHOU ; Xiaofan ZHAO ; Jinxing WANG
Chinese Journal of Biotechnology 2008;24(5):723-732
Lysozyme hydrolyses bacterial cell walls and acts as a nonspecific innate immunity molecule against the invasion of bacterial pathogens. We cloned the cDNA of lysozyme from Fenneropenaeus chinensis and named Fc-lysozyme (FcLyz in short). The full length of the gene was of 709 bp, and the open reading frame (477 bp) encoded 158 amino acids. The predicted protein had a signal peptide (-1--18 residue) and molecular weight of the mature protein (residue 1-140) was of 16.2 kD. A Lyz 1 domain (residue 1-130) in the lysozyme was found by SMART analysis. The results of semiquantity RT-PCR showed that FcLyz was constitutively expressed in tested tissues in a low level in normal shrimp, and up-regulated in hemocytes, heart, hepatopancreas and gill of bacterial challenged shrimp. The DNA fragment of mature Fc-Lys was subcloned to pET-30a (+) expression vector, the recombinant plasmid was transformed into Escherichia coli BL21 (DE3) and then induced by isopropylthio-beta-D-galactoside (IPTG). The antibacterial activity of the purified recombinant FcLys was analyzed and minimal inhibitory concentration (MIC) was assayed. The recombinant protein showed high antibacterial activity against some Gram-positive bacteria, and MIC reached 3.43 micromol/L, and relatively low activity against Gram-negative bacteria. All together, the Fc-Lys was regulated by pathogen infection and had antibacterial activity. This suggested that the FcLyz may be one of the important molecules against pathogens in innate immunity of the shrimp.
Amino Acid Sequence
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Animals
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Anti-Bacterial Agents
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biosynthesis
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Base Sequence
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Cloning, Molecular
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DNA, Complementary
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genetics
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Escherichia coli
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genetics
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metabolism
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Molecular Sequence Data
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Muramidase
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biosynthesis
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genetics
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Penaeidae
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enzymology
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genetics
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Recombinant Proteins
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biosynthesis
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genetics
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pharmacology
4.Rapid screening of MT3243A>G mutation in mitochondrial diabetes with high resolution melting curve analysis and pyrosequencing.
Xinjun WEI ; ; crwang@sjtu.edu.cn. ; Xiujuan DU ; Congrong WANG ; Jingbin YAN
Chinese Journal of Medical Genetics 2016;33(4):447-451
OBJECTIVETo establish a rapid, accurate, noninvasive and low cost method for screening MT3243A>G mutation in mitochondrial diabetes.
METHODSBlood, saliva, and urine sediment samples were collected from 6 patients with confirmed mitochondrial diabetes and 50 healthy controls from Shanghai Children's Hospital and Shanghai Sixth People's Hospital. The heterozygosity levels of MT3243A>G mutation in above samples were detected with pyrosequencing, and the data were compared. MT3243A>G mutations were rapidly screened with high resolution melting curve analysis (HRM) in the urine sediment samples of 1070 diabetic patients from 4 communities in Shanghai. Furthermore, pyrosequencing was used to validate the suspected positive samples, and the heterozygosity levels were also quantified.
RESULTSComparative experiments found that heterozygosity of MT3243A>G mutation was 2 to 7 times higher in urine sediment than in saliva and blood samples from the 6 patients with confirmed mitochondrial diabetes. However, the heterozygosity was slightly higher in saliva than blood samples. MT3243A>G mutation was not detected in the 50 healthy controls. Two samples with suspected MT3243A>G mutation were identified in the 1070 urine sediment samples of diabetes patients with HRM screening, which were validated by pyrosequencing. The heterozygosity of MT3243A>G mutation were 33.32% and 14.67% in the urine sediment samples, respectively.
CONCLUSIONUrine sediment samples can be used for rapid screening of MT3243A>G mutation for its ease to collect, noninvasiveness and higher level of heterozygosity. HRM is suitable for rapid screening for mitochondrian mutations for its low cost, while such mutations could be detected with sensitivity and accuracy by pyrosequencing.
DNA, Mitochondrial ; genetics ; Diabetes Mellitus ; genetics ; Heterozygote ; Humans ; Mutation ; Sequence Analysis, DNA ; methods ; Transition Temperature
5.An optimal medicinal and edible Chinese herbal formula attenuates particulate matter-induced lung injury through its anti-oxidative, anti-inflammatory and anti-apoptosis activities.
Huan ZHANG ; Jun KANG ; Wuyan GUO ; Fujie WANG ; Mengjiao GUO ; Shanshan FENG ; Wuai ZHOU ; Jinnan LI ; Ayesha T TAHIR ; Shaoshan WANG ; Xinjun DU ; Hui ZHAO ; Weihua WANG ; Hong ZHU ; Bo ZHANG
Chinese Herbal Medicines 2023;15(3):407-420
OBJECTIVE:
Identifying novel strategies to prevent particulate matter (PM)-induced lung injury is crucial for the reduction of the morbidity of chronic respiratory diseases. The combined intervention represented by herbal formulae for simultaneously targeting multiple pathological processes can provide a more beneficial effect than the single intervention. The aim of this paper is therefore to design a safe and effective medicinal and edible Chinese herbs (MECHs) formula against PM-induced lung injury.
METHODS:
PM-induced oxidative stress, inflammatory response and apoptosis A549 cell model were used to screen anti-oxidant, anti-inflammatory and anti-apoptotic MECHs, respectively. A network pharmacology method was utilized to rationally design a novel herbal formula. Ultra performance liquid chromatography-mass spectrometer was utilized to assess the quality control of MECHs formula. The excretion of magnetic iron oxide nanospheres of the MECHs formula was estimated in zebrafish. The MECH formula against PM-induced lung injury was investigated with mice experiments.
RESULTS:
Five selected herbs were rationally designed to form a new MECH formula, including Citri Exocarpium Rubrum (Juhong), Lablab Semen Album (Baibiandou), Atractylodis Macrocephalae Rhizoma (Baizhu), Mori Folium (Sangye) and Polygonati Odorati Rhizoma (Yuzhu). The formula effectively promoted the magnetic iron oxide nanospheres excretion in zebrafish. The mid/high dose formula significantly prevented PM-induced lung damage in mice by enhancing the activity of SOD and GSH-Px, reducing the MDA and ROS level and attenuating the upregulation of pro-inflammatory cytokine (IL-6, IL-8, IL-1β and TNF-α), down regulating the protein expression of NF-κB, STAT3 and Caspase-3.
CONCLUSION
Our findings suggest that the effective MECHs formula will become a novel strategy for preventing PM-induced lung injury and provide a paradigm for the development of functional foods using MECHs.