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.

For transcriptome analysis,it is critical to precisely define all the transcripts across the whole genome.More and more digital gene expression (DGE) scannings have indicated the presence of huge amount of novel transcripts in addition to the known gene models.However,almost all these studies still depend crucially on existing annotation.Here,we present Gene2DGE,a Perl software package for gene model renewal with DGE data.We applied Gene2DGE to the mouse blastomere transcriptome,and defined 98,532 read-enriched regions (RERs) by read clustering supported by more than four reads for each base pair.Taking advantage of this ab initio method,we refined 2,104 exonic regions (4％ of a total of 48,501 annotated transcribed regions) with remarkable extension into un-annotated regions (＞50 bp).For 5％ of uniquely mapped reads falling within intron regions,we identified 13,291 additional possible exons.As a result,we renewed 4,788 gene models,which account for 39％ of a total of 12,277 transcribed genes.Furthermore,we identified 12,613 intergenic RERs,suggesting the possible presence of novel genes outside the existing gene models.In this study,therefore,we have developed a suitable tool for renewal of known gene models by ab initio prediction in transcriptome dissection.The Gene2DGE package is freely available at http://bighapmap.big.ac.cn/.

Population genomic approaches,which take advantages of high-throughput genotyping,are powerful yet costly methods to scan for selective sweeps.DNA-pooling strategies have been widely used for association studies because it is a cost-effective alternative to large-scale individual genotyping.Here,we performed an SNP-MaP(single nucleotide polymorphism microarrays and pooling)analysis using samples from Eurasia to evaluate the efficiency of pooling strategy in genome-wide scans for selection.By conducting simulations of allelotype data,we first demonstrated that the boxplot with average heterozygosity(HET)is a promising method to detect strong selective sweeps with a moderate level of pooling error.Based on this,we used a sliding window analysis of HET to detect the large contiguous regions(LCRs)putatively under selective sweeps from Eurasia datasets.This survey identified 63 LCRs in a European population.These signals were further supported by the integrated haplotype score(iHS)test using HapMap Ⅱ data.We also confirrned the European-specific signatures of positive selection from several previously identified genes(KEL,TRPV5,TRPV6,EPHB6).In summary,our results not only revealed the high credibility of SNP-MaP strategy in scanning for selective sweeps,but also provided an insight into the population differentiation.

[Objective]To investigate primary and secondary transfer of exfoliated cells from human hands on non-porous substrates such as plastic steering wheel or computer mouse.[Methods]DNA 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'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.[Results]Our 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.[Conclusions]Primary 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.

The chromosome 17q21.31 inversion is a 900-kb common structural polymorphism found primarily in European population. Although the genetic flux within inversion region was assumed to be considerable suppressed, it is still unclear about the details of genetic exchange between the H1 (non-inverted sequence) and H2 (inverted sequence)haplotypes of this inversion. Here we describe a refined map of genetic exchanges between pairs of gene arrangements within the 17q21.31 region. Using HapMap phase Ⅱ data of 1,546 single nucleotide polymorphisms, we successfully deduced 96 H1 and 24 H2 haplotypes in European samples by neighbor-joining tree reconstruction. Furthermore, we identified 15 and 26 candidate tracts with reciprocal and non-reciprocal genetic exchanges, respectively.In all 15 regions harboring reciprocal exchange, haplotypes reconstructed by clone sequencing did not support these exchange events, suggesting that such signals of exchange between two sister chromosomes in certain heterozygous individual were caused by phasing error regions. On the other hand, the finished clone sequencing across 4 of 26 tracts with non-reciprocal genetic flux confirmed that this kind of genetic exchange was caused by gene conversion.In summary, as crossover between pairs of gene arrangements had been considerably suppressed, gene conversion might be the most important mechanism for genetic exchange at 17q21.31.

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.