Radar radiation damages sperm quality / 中华男科学杂志

<p><b>OBJECTIVE</b>To study the effects of radar radiation on sperm quality.</p><p><b>METHODS</b>A total of 348 infertile seamen were divided into 4 experimental groups according to their different lengths of exposure to radar radiation: Group 1 (n = 128) exposed for 12-36 months, Group 2 (n = 58) 37-72 m, Group 3 (n = 47) 73-108 m, Group 4 (n = 19) 109 m or more and Group 5 (n = 96) 48 m or more but free from the exposure for 6 months by then. Another 35 non-marine normal males were recruited as Control Group 1, and the first four experimental groups (n = 252) were taken as Control Group 2. Semen samples were collected from the subjects and analyzed statistically.</p><p><b>RESULTS</b>Compared with the normal control, sperm concentration, sperm motility and the percentage of grade a sperm were significantly lower (P < 0.01), and the percentages of grade d and abnormal sperm significantly higher (P < 0.01) in the experimental groups. In Group 5, obvious recovery was noted in sperm morphology (P < 0.01) and motility (P < 0.05), but significant differences were seen with the normal control group in sperm concentration (P < 0.05), sperm motility and the percentage of grade a and b sperm and that of abnormal sperm (P < 0. 01).</p><p><b>CONCLUSION</b>Radar radiation damages sperm quality, as shown in the reduction of sperm motility and elevation of sperm abnormality. Cease from the exposure may effect an easy recovery in sperm morphology.</p>

Enhancement of exogenous gene expression by artificial transcription factor in CHO cells / 生物工程学报

Using the amino acids 1-147 of the yeast transcriptional activator GAL4 as the DNA-binding domain and four tandem repeats of the 12-aa peptide (DALDDFDLDMLG) of the herpesvirus as the activation domain, an artificial transcription factor, GVP4,was constructed via the linkage of the nuclear localization signal sequence of SV40. And then, GVP4 was cloned into expression vector pcDNA3 . 1/Hygro ( + ) . Various amounts of targeting sites of artificial transcription factor were linked to the upstream of promoter CMV in exogenous gene expression vector pcDNA3.1 ( + ) that separately harbored EGFP cDNA and t-PA cDNA.The CHO cells were then co-transfected with GVP4 expression vector and EGFP or t-PA expression vector. The effect of GVP4 on exogenous gene expression was evaluated by measuring the fluorescence intensity of EGFP in CHO cells and the concentration of t-PA in the supernatant. GVP4 showed positive effect on the enhancement of exogenous gene expression in CHO cells integrated with targeting sites of artificial transcription factor. And, CHO cells integrated with 10 targeting sites of GVP4 was more favorable to foreign gene expression, which resulted in 2-3-fold increase in both EGFP and t-PA expressions. These results indicated that artificial transcription factor is potent in the enhancement of exogenous gene expression in mammalian cells.

Effects of hydrodynamic on aggregates formation, growth and metabolism of HEK293 cells in suspension culture / 生物工程学报

By using the size distribution of cell aggregates, viable cell density, cell viability, specific consumption rate of glucose (q(glc)), specific production rate of lactate (q(lac)) and lactate transform rate (Y(lac/glc)) as the evaluation indexes, the effects of hydrodynamic on aggregates formation, growth and metabolism of HEK293 cells in suspension culture were examined in 250mL spinner-flasks by setting the agitation rates at 25, 50, 75 and 100r/min, respectively. It was found that agitation plays an important role in HEK293 cell aggregates formation and cell aggregates size distribution. After 7d cultivation in spinner-flasks operated at 50r/min and 75r/min, the average diameter of HEK293 cell aggregates was 201 microm and 175 microm, respectively, with the fraction of aggregates larger than 225 microm less than 10%. The cell viability was kept above 90% with the metabolic indexes, including q(glc), q(lac) and Y(lac/glc) kept constant. These results demonstrated that hydrodynamic derived from the proper agitation play a decisive role in controlling the formation and size distribution of HEK293 cell aggregates, and provided sufficient mass transfer to support the normal growth and metabolism of HEK293 cells in suspended aggregates.

In vitro cytolysis of B-lymphoma cells mediated by an anti-CD3/anti-CD20 bispecific single-chain antibody / 生物工程学报

After having successfully constructed and expressed the gene of the anti-CD3/anti-CD20 bispecific single-chain antibody (bscCD3 x CD20), here we analyzed its in vitro bioactivity of mediating the lysis of Ramous human B-lymphoma cells in the presence of T-enriched human peripheral blood lymphocytes (PBL). Obvious opoptosis characters were observed by Annexin V/PI(AV/PI) stained and scanning electron microscope. As evaluated by non-radioactive cytotoxity assay, the bscCD3 x CD20 showed potent bioactivity of mediating human B-lymphoma cells lysis in the presence of T-enriched human PBL. The potency of cytotoxicity depended on the ratios of effect cells to target cells (E:T) used. Further, the antibody showed a dose and time-dependent effect on mediating Ramous cells lysis. The specific lysis reached about 87.3% at an antibody concentration of 5microg/mL and E:T used at 10:1. Clear changes in apoptogenes expression profiles were detected by apoptosis gene array after Ramous cells were treated with the antibody and PBL. Among the upregulated apoptogenes, ATM and P53 showed an increase of 187 times and 15 times respectively, which suggested that ATM-p53 pathway may be the main apoptosis way of Ramous cells induced by T cells in the presence of the bscCD3 x CD20.

Stirred Bioreactor Cultivation Enhances the Efficiency of Embryoid Bodies Formation and Differentiation into Cardiomyocytes / 中国生物工程杂志

Objective:To determine the optimal condition for mouse embryonic stem cells (mESC) culture with stirred bioreactor,and to develop a method for mass production of embryoid bodies (EB). Methods:The different initial cell concentrations of mESC and the initial stirring speed of bioreactor were investigated to determine the optimal condition for EB formation. Induced by ascorbic acid,the differentiation of EBs formed in stirred bioreactor into cardiomyocytes was compared with EBs formed in Petri dish. Immunofluorescence staining and RT-PCR were used to identify the cardiomyocytes derived from mESC. Results:The formation of a large number of uniform relatively EBs was achieved in stirred bioreactor when mESC were seeded initially with 1?105~3?105 cells/ml and stirring speed was set to 15~30r/min. Most of cells in the EBs formed in bioreactor were viable. EBs produced in bioreactor differentiated into cardiomyocytes more efficiently compared with EBs from Petri dish. The cardiac specific genes were expressed in ESC-derived cardiomyocytes. Conclusions:Stirred bioreactor culture could enhance the efficiency of EB formation and differentiation into cardiomyocytes,which may be a more ideal culture system for EB formation.

A High-throughput and Quantitative Assay Based on Fluorescence Intensity for Detection of Apoptosis / 中国生物工程杂志

Based on the different permeability of DNA-intercalant dyes YO-PRO-1(YP) and propidium iodide (PI) to the membrane of viable, apoptotic and necrotic cells, cell samples were stained with 4?mol/L YP and 4?g/ml PI for 10 min, and the fluorescence intensity of both YP and PI were measured by fluorometer at Ex/Em wavelength of 485/538nm and 530/590nm, respectively. The correlation between YP fluorescence intensity and the apoptotic cell number was confirmed by fluorescence microscope and linear regression(r=0.999,P

Characteristics of HEK293 Cells Growth and Metabolism under Carrier-free Immobilization Culture Mode / 中国生物工程杂志

By using the cell density, cell viability, size distribution of cell aggregates,specific consumption rate of glucose (q_ glc ), specific production rate of lactate (q_ lac ), lactate transform rate (Y_ lac/glc ) and amino acids utilization as the evaluation indexes, the growth and metabolism of HEK293 cells under carrier-free immobilization culture mode were examined and compared with those of HEK293 cells cultured in static tissue flasks. It was found that HEK293 cells grown as suspended cell aggregates in spinner flasks maintained the basic growth and metabolism characteristics of HEK293 cells in stationary anchored culture, and HEK293 cells under carrier-free immobilization culture mode as suspended aggregates in stirred bioreactor facilitate perfusion performance and increase unit productivity. Cultivation of HEK293 cells in carrier-free immobilization culture mode has potential for further improving mammalian cells culture technique.

Expression, identification and bioactivity characterization of an anti-CD3/anti-CD20 bispecific single-chain antibody / 生物工程学报

The synthetic gene with 1640bp encoding for the anti-CD3/anti-CD20 bispecific single-chain antibody was designed and obtained by SOE (splicing by overlap extension) PCR. The cDNA was cloned into Flp-In expression vector pcDNA5/FRT and transfeced into Flp-In CHO cells to generate a stable expression cell line with a capacity for expressing anti-CD3/anti-CD20 bispecific single-chain antibody at 300 microg/L. The protein, which had a molecular weight of about 70 kD,was purified by Ni-NTA affinity chromatography and identified by SDS-PAGE and Western-blot analysis. Immunofluorescence assay and cellular rosetting showed that it can react specifically on Jurkat (CD3+) and Ramous (CD20+) cells. The lysis of human PBL against CD20-positive lymphoma Ramous cells in the presence of the anti-CD3/anti-CD20 bispecific single-chain antibody can observed by microscope. All these results would lighten the further study of its biological functions in vitro and in vivo.