Objective:To prepare the bacterial outer membrane vesicles(OMV)that can express programmed death ligand 1(PD-L1)nanobody on surface,and to discuss its structural characteristics,cell compatibility,intracellular distribution,and its blocking effect on the programmed cell death protein-1(PD-1)/PD-L1 signaling axis.Methods:The pET28a-ClyA-PD-L1nb prokaryotic expression vector was constructed and transformed into Escherichia coli BL21(DE3)competent cells;the OMV was isolated from the BL21(DE3)monoclonal colonies transformed with the PD-L1nb expression vector by ultracentrifugation;the protein purification was performed using the histidine(His)tag;transmission electron microscope and nanoparticle size analyzer were used to analyze and identify the OMV;the OMV isolated from the BL21(DE3)monoclonal colonies transformed with the PD-L1nb expression vector was used as experimental group;the OMV isolated from the untransformed BL21(DE3)monoclonal colonies was used as control group;Western blotting method was used to detect the expression levels of ClyA-PD-L1nb fusion protein in the OMV in two groups;cell counting kit-8(CCK-8)assay was used to detect the activities of mouse macrophage RAW 264.7 cells,mouse triple-negative breast cancer 4T1 cells,and human embryonic kidney HEK293T cells after treated with OMV;fluorescence imaging technology was used to observe the tumor cell endocytosis of OMV;flow cytometry was used to detect the binding effect of OMV to the PD-L1 on surface of the tumor cells in PBS group,OMV-PD-L1nb group,and aPD-L1+OMV-PD-L1nb group.Results:The sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE)results showed that after induction of Escherichia coli,significantly thickened protein bands appeared near the predicted relative molecular mass(about 49 000),and after purification,no obvious impurity proteins existed in the lanes;the OMV-PD-L1nb with a size of about 120 nm was isolated by ultracentrifugation,and it presented a uniform spherical structure under transmission electron microscope;the Western blotting results showed that the specific band of ClyA-PD-L1nb was detected in the OMV in experimental group;the CCK-8 assay results showed that after treated with different concentrations of OMV,the viabilities of the RAW 264.7 cells,4T1 cells,and HEK293T cells were all close to 100％;the fluorescence imaging results showed that OMV-PD-L1nb was endocytosed by 4T1 cells and dispersed in the cytoplasm;compared with OMV-PD-L1nb group,the average fluorescence intensity in the cells in aPD-L1+OMV-PD-L1nb group was significantly decreased(P＜0.001).Conclusion:The OMV surface-displaying PD-L1nb,OMV-PD-L1nb,is successfully prepared and isolated;OMV-PD-L1nb shows good compatibility on mouse macrophage cells,tumor cells,and human embryonic kidney cells,can be endocytosed by tumor cells,and successfully blocks the PD-1/PD-L1 signaling pathway.

ObjectiveTo investigate the changes of differential metabolites in the serum of mice at different stages of bleomycin sulfate（BLM）-induced pulmonary fibrosis modeling and administration， and the mechanism of Wenfei Huaxian granules（WHG）against idiopathic pulmonary fibrosis. MethodMice were randomly divided into control group， control group of 14 days， model group， model group of 14 days， low-dose WHG group and high-dose WHG group. BLM（0.04 U per mouse）was injected into the trachea of mice in the model group， model group of 14 days， low-dose WHG group and high-dose WHG group， and sterile normal saline was injected into the trachea of mice in the control group and control group of 14 days. Mice of low-dose WHG group and high-dose WHG group were given different doses of WHG by gavage every day after injection of BLM， and mice of control group， control group of 14 days， model group and model group of 14 days were given sterile water by gavage every day. The peripheral blood of mice in the control group of 14 days and model group of 14 days were taken to prepare serum after injection of BLM for 14 days， and the peripheral blood and other materials of mice in the other groups were taken after continuous administration for 28 days. The bronchoalveolar lavage fluid（BALF）was collected for leucocyte differential count， the pathological examination and hydroxyproline（HYP）content determination of lung tissues of mice were performed， and the small molecule metabolites in serum samples of mice in each group were determined by ultra-high performance liquid chromatography-mass spectrometry（UHPLC-MS）. Principal component analysis（PCA）and orthogonal partial least squares-discriminant analysis（OPLS-DA）were conducted to screen differential metabolites and their biological functions were analyzed. ResultCompared with the control group， a large number of continuous fibrotic foci appeared in the lung tissue of mice in the model group， the alveolitis score， fibrosis degree score and HYP content increased significantly（P<0.01）， and the total number of leukocytes， macrophages and lymphocytes in BALF increased significantly（P<0.05）. A total of 33 differential metabolites were screened between the control group of 14 days and model group of 14 days， mainly lipid metabolites， which were mainly involved in oxidative damage and inflammatory process. A total of 34 differential metabolites， mainly amino acid metabolites， were screened between the control group and model group， mainly involving nucleic acid damage and inflammatory process. Compared with the model group， the HYP content， fibrosis score and alveolitis score in the lung tissue of mice from high-dose WHG group decreased significantly（P<0.05， P<0.01）， and the total number of lymphocytes in BALF decreased significantly（P<0.05）. Compared with the model group， 27， 40 differential metabolites were identified in the serum of mice from the low-dose WHG group and high-dose WHG group separately. There were totally 9 common differential metabolites between the model group and low-dose WHG group/high-dose WHG group， which mainly involved in the metabolic pathways of inflammation related lipids metabolism， arginine and tryptophan metabolism， and the change trends in low-dose WHG group and high-dose WHG group were significantly back-regulated compared with the model group. ConclusionWHG can alleviate BLM-induced pulmonary fibrosis， collagen deposition and inflammatory reaction in mice， and its anti-fibrotic effect may be related to the adjusting of inflammatory factors， nitric oxide and oxidative stress related metabolic pathways.

OBJECTIVE: To analyze the effect of occupational stress on abnormity of serum total cholesterol and triglyceride in male steel workers. METHODS: A total of 3 957 male steel workers from an iron and steel group company were selected as study objects by judgment sampling method. Occupational stress was measured by the Chinese version of Job Content Questionnaire. The serum total cholesterol and triglyceride levels were measured using fasting venous blood. RESULTS: Among the 3 957 workers,the detection rate of occupational stress was 56. 8%,and 55. 0% of them showed high social support. The abnormal rates of total cholesterol and triglyceride were 21. 8% and 40. 9%,respectively. The multivariate logistic regression analysis showed that workers with high social support had high risk of abnormal total cholesterol and abnormal triglyceride than workers with low social support( P < 0. 05) after adjusting for confounding factors such as age,education level,marital status,body mass index,smoking and drinking alcohol,tea. The odds ratio of abnormal total cholesterol in occupational stress workers was 1. 17 times of that of non-occupational stress workers. No association was found between occupational stress and abnormal triglyceride( P > 0. 05). CONCLUSION: Occupational stress may be associated with abnormity of total cholesterol in male steel workers. Social support is an important influences factor to the abnormity of total cholesterol and triglyceride in male steel workers.

Objective To present a miniaturized nucleic acid amplification system for spot rapid detection .Methods A miniaturized nucleic acid amplification system with structured packed porous media of particles to uniform the air temperature was designed according to the working principle and heat transfer characteristics of an air -heated nucleic acid amplification system.Thermodynamic simulation and temperature cycling test were carried on to verify the feasibility of the system.Results The structured packed porous media of particles worked well in uniforming the air temperature of the system and the temperature uniformity could reach 0.8℃.The miniaturized nucleic acid amplification system with a volume parameter of 80 mm ×40 mm ×20 mm(length ×height ×width)was portable.The average rate of heating was 10℃/s while the average rate of cooling was 5℃/s.Compared with standard PCR instrument , the miniaturized nucleic acid amplification system performed well in the process of amplification and met the requirements of preliminary design .Conclusion The miniaturized nucleic acid amplification system with a rapid reaction velocity and portable volume could be applied to nucleic acid detection of unknown samples on the spot .