[Study on genomic stability of male workers in an e-waste dismantling area in Tianjin].

Objective: To study on the genomic stability of male workers engaged in e-waste dismantling area in Tianjin. Methods: In 2016, an e-waste dismantling area in Tianjin and an area 50 km away from the e-waste dismantling area (no e-waste or other chemical, industrial and agricultural pollution nearby) were selected as the study area and the reference area. Male residents of the study area and male farmers who planted vegetables, fruits, and crops in the reference area were selected as the exposed and reference group by using the convenient sampling method. The exposed group included 146 workers who engaged in e-waste recycling work more than 1 year. The reference group included 121 farmers who never engaged in e-waste recycling work. Questionnaires were used to collect information of all subjects. The semen and peripheral blood were also collected. Trace elements and polychlorinated biphenyl concentration in blood were detected. DNA damage in peripheral blood and sperm was detected, and gene expression was analyzed. DNA damage was assessed using tail DNA% (TDNA%), tail moment (TM) and olive tail moment (OTM) of comet assay. Results: The ages of the exposed group and the reference group were (33.6±12.1) and (33.9±11.9) years old, respectively. The proportions of subjects with exposure time of ≤3, 4-6, ≥7 years were 43% (63 cases), 26% (53 cases) and 21% (30 cases), respectively. The Pb and polychlorinated biphenyl(PCB) concentrations in the exposed group [(90.4±15.3) µg/ml and (101±30) ng/ml, respectively] were higher than those in the reference group [Pb and PCB concentrations were (60.2±8.9) µg/ml, and (2.5±1.4) ng/ml, respectively (both P values <0.05)]. The TDNA%, TM and OTM of peripheral blood and sperm in the exposed group were 5.9%±0.3% and 2.6%±0.90%, 0.93±0.16 and 0.51±0.20, 0.82±0.09 and 0.56±0.07, respectively, which were all higher than those in the reference group [TDNA%, TM and OTM of peripheral blood and sperm were 1.8%±0.2% and 1.9%±0.2%, 0.21±0.04 and 0.32±0.10, 0.19±0.03 and 0.20±0.08, respectively (all P values <0.001)]. The results of gene expression showed that 20 differentially expressed genes, including 13 up-regulated genes and 7 down-regulated genes, were detected in the exposed group compared with the reference group. Conclusion: There are obvious DNA damage and DNA repair gene disorder in male workers of an e-waste dismantling area in Tianjin. The current operation mode brings potential health risks to workers.

[Study on the exposure of polychlorinated biphenyl contamination and DNA methylation in male employees in an e-waste dismantling area in Tianjin].

Objective: To study on the exposure of polychlorinated biphenyl (PCB) contamination and DNA methylation in male employees in an e-waste dismantling area in Tianjin. Methods: In 2016, an e-waste dismantling area in Tianjin and an area 50 km away from the e-waste dismantling area (no e-waste or other chemical, industrial and agricultural pollution nearby) were selected as the study area and the reference area. Male residents of the study area and male farmers who planted vegetables, fruits, and crops in the reference area were selected as the exposed and reference group by using the convenient sampling method. A total of 60 subjects (30 in each of the exposed group and the reference group) were included. The peripheral blood (5 ml) of the study subject was collected, and the PCB concentration was detected. Eight independent subjects in the exposed group and the reference group were randomly selected by random number table method to detect the methylation level of the promoter region of all gene loci, and the mRNA transcript levels. Results: The PCB concentration in peripheral blood of the exposed group was higher than that of the reference group, and the difference was statistically significant (allP values <0.001). The methylation levels of the promoter region of the exposed group and the reference group showed obvious clustering, and 994 gene loci had different degrees of methylation. Compared with the reference group, there were 391 hypomethylation sites and 553 hypermethylation sites in the exposed group. The proportion of methylation sites in the high CpG-rich region was 59.2% and 48.1%, respectively. The mRNA level of the hypomethylated gene in the exposed group was higher (FAM131A, HBM), and the transcription level of the hypermethylated gene was lower (CAPN15, NFIC, SHISA5, FGF13, GRAMD1A, CLEC3B, LILRB2, DCAF7). The mRNA transcription levels of 10 genes above in the exposed group and the reference group were statistically significant (all P values <0.001). Conclusion: The PCB concentration of peripheral blood in the exposed population of e-waste is high. PCB exposure changes the methylation level of specific genes and affects the mRNA transcription level of some genes.

Preparation and immune activity analysis of H5N1 subtype avian influenza virus recombinant protein-based vaccine.

Avian influenza is a severe disease among farmed poultry and free-living birds and a constant threat to the commercial chicken industry around the world. Hemagglutinin (HA) is the major immunogen on the envelope of influenza A virus and is the predominant inducer of neutralizing antibody. To obtain the bioactive antigen proteins in large quantities, a new protein expression vector pBCX was constructed, which is based on the pET32a vector. The HA gene of the H5N1 subtype of avian influenza virus (AIV) was inserted into the pBCX vector and expressed efficiently in Escherichia coli BL21 (DE3). Fused expression of the exogenous gene and msyB produced a 97-kDa msyB-HA fusion protein. Sodium dodecyl sulfate-PAGE combined with scanning analysis demonstrated that the msyB-HA fusion protein accounted for 29.5% of the total bacterial protein, 90.5% being soluble. The msyB-HA fusion protein was purified with nondenaturing 50% Ni-NTA column chromatography, and the result showed that 24 mg of purified msyB-HA fusion protein could be obtained from 1 L of induced expression bacterial culture medium. The comparative results in the present study showed that pBCX was superior to pET32a as a protein expression vector. Western blotting showed the recombinant msyB-HA (rHA) to have better antigenic activity, which may be the result from the better posttranslation protein modification and folding in the pBCX expression system. With the rHA fusion protein as antigen, we successfully prepared and screened specific monoclonal antibodys against the H5N1 subtype AIV, which indicated that the rHA had antigen epitopes and biofunctions. The immune test confirmed that the rHA protein vaccine could also induce high neutralizing antibodies, and the AIV challenge test proved that the rHA protein-based vaccine could prevent the corresponding infection. This study demonstrates that the recombinant HA protein produced by the pBCX expression system could be used as a recombinant protein-based vaccine and has potential for further development for diagnosis.

[High efficient intergeneric chromosomal translocations between wheat (Triticum aestivum L.) and Dasypyrum villosum arising from tissue culture and irradiation].

Intergeneric chromosomal translocations were discernable both in callus cells and in regenerants arising from crosses between Triticum aestivum and T. durum-Dasypyrum villosum amphiploid c.v. TH1 and TH1W by means of fluorescence in situ hybridization. There were not only reciprocal translocations, but small fragment translocations. The results proved again the feasibility of creating intergeneric translocations via tissue culture. Irradiation facilitated numerical and structural chromosome changes in callus cells. The frequency of translocations was as high as 7.4 percent in irradiated callus cells. Callus age had an important impact on numerical and structural chromosome abnormalities. During a given time of culture, the frequency of unchanged cells was declined, while those cells with chromosome losses were inclined. The duration of culture had not significant effects on cells with chromosome gains. As structural chromosome changes is concerned, the duration of culture predominantly increased the frequency of cells with telocentric chromosomes. The chromosomal changes occurred at the initiation period of tissue culture. A number of cells which were doubled their chromosome numbers (2n = 84) were observed at a certain frequency in the period of tissue culture. These cells, however, disappeared in the successive culture.

Genetic transformation of Lycium barbarum L. via A. tumefaciens.

A system for transformation and regeneration of Lycium barbarum L., an important Chinese medical plant, has been established. Young stem segments from Lycium barbarum L. were infected with Agrobacterium tumefaciens C58cl(pGV3850::neo1103), and the transformed calli selected from the callus induction medium containing 50 micrograms/ml kanamycin could regenerate buds on differentiation medium containing 25 micrograms/ml kanamycin. 30% of the regenerated buds were normal in morphology. The normal buds could develop into whole plantlets after they were transferred to the rooting medium to induce roots. Nopaline detection, NPT-II enzyme activity assay and Southern blotting hybridization indicated that the foreign genes had been integrated into the genome of Lycium barbarum L. and expressed in the plant. In the processes of experiments, it was found that (i) after the pre-processes, the explants which formed callus quickly were easy to transform; (ii) the rate of normal regenerated plants from transgenic calli was higher than that from the untransgenic ones.

Molecular cytogenetic analysis of intergeneric chromosomal translocations between wheat (Triticum aestivum L.) and Dasypyrum villosum arising from tissue culture.

Fluorescence in situ hybridization (FISH) was applied with total genomic DNA extracted from Dasypyrum villosum (L.) Candargy as a probe to characterize chromosome translocations arising from tissue culture in hybrids of Triticum aestivum x (T. durum - D. villosum, amphiploid). Chromosome translocations between wheat and D. villosum occurred in callus cells at an average frequency of 1.9%. Translocations existed not only in callus cells but also in regenerants. Three plants with translocation chromosomes were characterized among 66 regenerants of T. aestivum 'Chinese Spring' x 'TH1W' and 'NPFP' x 'TH1'. One of them proved to be a reciprocal translocation with an exchange of about one third of a wheat chromosome arm with about one half of a chromosome arm of D. villosum. The breakpoints of the other two translocations were located at, or near centromeres. The results are similar for both callus cells and regenerants and provide further evidence that translocations take place in tissue culture. Other structural chromosomal changes, for example, fragments, telocentrics, dicentromeres, and deletions, as well as numerical alterations including aneuploidy and polyploidy were recorded both in callus cells and regenerants.

Influence of frame rate and image delay on virtual driving performance.

The control and navigation of unmanned ground vehicles (UGVs) by humans requires a thorough understanding of the limitations in human perception and performance. Images of the external world recorded by cameras mounted on the UGV are presented as a video display to the operator, who then remotely manipulates the vehicle using a standard control. Operator performance is directly proportional to the computational complexity associated with the processing of video data. This work studies the effects of frame rate and image delay (lag) on remote driving performance. Experiments were conducted with five subjects using a driving simulator with a 1 dof force feedback steering wheel control. After sufficient training on the simulator, subjects drove a virtual car on a standard track under varying settings of frame rate and lag. Performance was measured by the duration to complete the course. Comparison of performance both within and between subjects showed characteristic driving patterns at different settings. Implications of the findings are discussed in relation to video data presentation for remote driving applications.