Objective To detect DNA damage in rat lymphocytes and brain cells induced by tetramine and study the toxicological mechanism of tetramine.Methods Lymphocytes and brain cells were separated and collected from healthy rats.DNA damages of cells which were exposed to various doses of tetramine for 60 min was detected using the single cell gel electrophoresis (SCGE) or comet assay.Results These are different degree DNA damages of lymphocytes and brain cells exposed from doses 1/20 LD 50 doses of tetramine to 1/2 LD 50 doses of tetramine.The test groups are very significantly statistical different to the control group(P

Objective To observe the change of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene expression during 3T3-L1 adipocyte differentiation as well as other reference gene expressions.Methods The mRNA expressions of several common reference genes were detected by real time-PCR on day 0,1,3,5,and 7 of 3T3-L1 adipocyte differentiation.Western blot was used to confirm the protein expressions of three common reference genes.Results (1) GAPDH and transferrin receptor(TFRC) mRNA expressions were significantly increased during adipocyte differentiation.GAPDH mRNA level was increased by 5.7,7.6,22.0,and 24.5 folds on day 1,3,5,and 7 after induction of adipocyte differentiation,but no apparent changes of β-actin,α-tubulin,peptidylprolyl isomerase A (PIPA),and 18S mRNA expressions were detected.The expression changes of key transcript factors for adipocyte differentiation such as PPARγ2,C/EBPα,and C/EBPβ were under-estimated by real time-PCR if GAPDH was chosen as the reference gene.Western blotting results showed that the GAPDH protein level increased gradually during adipocyte differentiation,especially on day 5 and 7 after adipocyte differentiation.There were no obvious changes of β-actin and α-tubulin protein expressions.(2) Berberine significantly inhibited mRNA and protein expressions of GAPDH in the process of adipocyte differentiation.GAPDH mRNA levels were reduced by 68.1％ and 66.3％ on day 5 and 7 after induction of adipocyte differentiation,but with no significant change in other reference genes.Conclusion It is not suitable for GAPDH to be used as an endogenous reference gene during 3T3-L1 adipocyte differentiation.

ObjectiveTo investigate primary and secondary transfer of exfoliated cells from human hands on non-porous substrates such as plastic steering wheel or computer mouse. MethodsDNA detection sensitivity and detection limit for mixed DNA profiling were examined to understand our laboratory’s ability to test for trace DNA. Forensic swabs were used to collect samples from volunteers’ one-hour-long unwashed hands， substrates touched by volunteers’ dominant hand 30 min after hand washing， substrates touched by volunteers 30 min after washing their hands and then immediately or 30 min following shaking hands， and individual A’s daily-use substrates touched by individual B and then by individual A again. Simulations were conducted to assess the potential for introduction of another person’s exfoliated cells from hands into routine casework samples. ResultsOur laboratory can obtain a full DNA profile from as little as 0.020 ng of DNA and detect minor components in a 1：9 mixed DNA sample. 85% of samples from unwashed hands yielded a full DNA profile. Primary transfer of a full DNA profile was found in 77% of substrates touched by volunteers’ dominant hand 30 min after hand washing， allowing differentiation between good and poor shedders， with no significant difference in genders and substrate types. 75% of substrates touched 30 min after hand washing and then immediately following handshaking yielded the other individual’s DNA profile （secondary transfer）， with the number of short tandem repeat （STR） loci detected ranging from 0 to 23； the percentage and number decreased substantially when the substrates were touched 30 minutes later. No foreign DNA was detected in routine casework samples with introduced exfoliated cells from hands. When two individuals took turns touching items with their hands， the major contributor to the DNA profile was not always the individual who made the last contact. ConclusionsPrimary and secondary DNA transfer can be detected on non-porous substrates， and based on the deposit of hand exfoliated cells， individuals can be categorized as good or poor shedders， which is an important factor affecting detection of DNA transfer. Besides considering the laboratory’s DNA detection sensitivity， if DNA is detected on substrates by hand contact， we need to take into account the potential for secondary transfer at different levels of activity when interpreting the results.

Objective: To study the etiological characteristics of an imported Chikungunya fever (CHIK) epidemic in Fujian province in 2018. Methods: Serum samples collected at different days after the onset of the two CHIK cases were detected by real-time RT-PCR and ELISA. Structural protein E1 gene was amplified by RT-PCR and sequenced for nucleotide characteristics analysis and phylogenetic tree analysis. Results: RNA of Chikungunya virus (CHIKV) was detected in the 4 serum samples collected on the first 5 days of the disease, and the earliest IgM antibodies were detected in specimens on the 5th day of the disease, however, IgG antibodies were only detected in specimen on 10th day. Compared with the S27-African prototype strain, 12 mutant points were found in the amino acids of E1 genes in this study. The E1 genes of the two CHIK cases were exactly the same, and they were closest to the evolutionary relationship with the strain isolated in the Philippines in 2014. Their genotype was Asian genotype. Conclusions This epidemic was confirmed to have been imported from the Philippines after the infection with the Asian genotype CHIKV, which suggests that Fujian province should strengthen the monitoring of persons entering from the CHIK epidemic area, so as to prevent imported cases from causing local outbreaks.