过多的水平性表达——论三联海边图书馆的设计意图与形式策略

本文从设计意图与形式策略一致性的角度出发,分析了北戴河新区三联海边图书馆形式生成过程中的得与失。

四环素胁迫对Shigella flexneri细菌四环素抗性基因抗性表达的影响过程

四环素(TC)抗生素在不同环境介质中已被广泛检出,为研究其对四环素抗性基因(TC-ARGs)丰度变化及表达水平的影响过程,以从活性污泥中筛选和纯化分离获得的弗氏志贺氏菌(Shigella flexneri)为研究对象,考察了不同浓度TC对其生长过程的作用影响,采用荧光定量PCR和逆转录PCR方法定量检测了不同抗性机制TC-ARGs,包括tetC、tetO和tetX基因的丰度变化及表达水平,并探讨了TC浓度与TC-ARGs丰度及其表达水平之间的相关关系.结果表明,在培养周期内(24 h),TC胁迫对Shigella flexneri细菌的生长具有抑制作用,细菌细胞浓度增长速率随TC暴露浓度的升高而降低,但对TC-ARGs丰度变化影响较小.TC胁迫能够促进Shigella flexneri细菌TC-ARGs的转录表达,tetC、tetO和tetX基因表达水平在整个培养周期内均先升高后降低.由相关性分析可知,TC浓度与TC-ARGs丰度及其表达水平之间相关关系不显著,但tetC和tetO基因丰度与其转录表达水平之间存在显著的正相关关系,表明其基因丰度一定程度上可用来衡量和评价其抗性表达水平.

Genetic and epigenetic variants influencing the development of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease （NAFLD） is common worldwide. The importance of genetic and epigen- eric changes in etiology and pathogenesis of NAFLD has been increasingly recognized. However, the ex- act mechanism is largely unknown. A large number of single nucleotide polymorphisms （SNPs） related to NAFLD has been documented by candidate gene studies （CGSs）. Among these genes, peroxisome pro- liferatoractivated receptor-γ, adiponectin, leptin and tumor necrosis factor-α were frequently reported. Since the introduction of genome-wide association studies （GWASs）, there have been significant advances in our understanding of genomic variations of NAFLD. Patatin- like phospholipase domain containing family member A3 （PNPLA3, SNP rs738409, encoding I148M）, also termed adiponutrin, has caught most attention. The evidence that PNPLA3 is associated with increased hepatic fat levels and hepatic inflammation has been validated by a series of studies. Epigenetic modification refers to phenotypic changes caused by an adaptive mechanism unrelated to alteration of primary DNA se- quences. Epigenetic regulation mainly includes microR- NAs （miRs）, DNA methylation, histone modifications and ubiquitination, among which miRs are studied most extensively, miRs are small natural single stranded RNA molecules regulating mRNA degradation or translation inhibition, subsequently altering protein expression of target genes. The miR-122, a highly abundant miR ac- counting for nearly 70% of all miRs in the liver, is sig- nificantly under-expressed in NAFLD subjects. Inhibition of miR-122 with an antisense oligonucleotide results in decreased mRNA expression of lipogenJc genes and improvement of liver steatosis. The investigation into epigenetic involvement in NAFLD pathogenesis is just at the beginning and needs to be refined. This review summarizes the roles of genetics and epigenetics in the development of NAFLD. The progress made in this field may provide novel diagnostic biomarkers and therapeu- tic targets for NAFLD management.

Tumor necrosis factor alpha increases intestinal permeability in mice with fulminant hepatic failure

AIM:To determine the effect of tumor necrosis factor alpha(TNF-α) on intestinal permeability(IP) in mice with fulminant hepatic failure(FHF),and the expression of tight junction proteins.METHODS:We selected D-lactate as an index of IP,induced FHF using D-galactosamine/lipopolysaccharide and D-galactosamine/TNF-α,assessed the results using an enzymatic-spectrophotometric method,transmission electron microscopy,immunohistochemistry,Western blotting and real-time quantitative polymerase chain reaction.The effect of the administration of antiTNF-α immunoglobulin G(IgG) antibody,before the administration of D-galactosamine/lipopolysaccharide,on TNF-α was also assessed.RESULTS:IP was significantly increased in the mouse model of FHF 6 h after injection(13.57 ± 1.70 mg/L,13.02 ± 1.97 mg/L vs 3.76 ± 0.67 mg/L,P = 0.001).Electron microscopic analysis revealed tight junction(TJ) disruptions,epithelial cell swelling,and atrophy of intestinal villi.Expression of occludin and claudin-1 mRNA was significantly decreased in both FHF models(occludin:0.57 ± 0.159 fold vs baseline,P = 0.000;claudin-1:0.3067 ± 0.1291 fold vs baseline,P = 0.003),as were the distribution density of proteins in the intestinal mucosa and the levels of occludin and claudin-1 protein(occludin:0.61 ± 0.0473 fold vs baseline,P = 0.000;claudin-1:0.6633 ± 0.0328 fold vs baseline,P = 0.000).Prophylactic treatment with antiTNF-α IgG antibody prevented changes in IP(4.50 ± 0.97 mg/L vs 3.76 ± 0.67 mg/L,P = 0.791),intestinal tissue ultrastructure,and the mRNA levels of occludin and claudin-1 expression(occludin:0.8865 ± 0.0274 fold vs baseline,P = 0.505;claudin-1:0.85 ± 0.1437 fold vs baseline,P = 0.1),and in the protein levels(occludin:0.9467 ± 0.0285 fold vs baseline,P > 0.05;claudin-1:0.9533 ± 0.0186 fold vs baseline,P = 0.148).CONCLUSION:Increased in IP stemmed from the downregulation of the TJ proteins occludin and claudin-1,and destruction of the TJ in the colon,which were induced by TNF-α in FHF mice.

PRAME Gene Expression in Acute Leukemia and Its Clinical Significance

Objective To investigate the expression of the preferentially expressed antigen of melanoma （PRAME） gene in acute leukemia and its clinical significance. Methods The level of expressed PRAME mRNA in bone marrow mononuclear cells from 34 patients with acute leukemia （AL） and in 12 bone marrow samples from healthy volunteers was measured via RT-PCR. Correlation analyses between PRAME gene expression and the clinical characteristics （gender, age, white blood count, immunophenotype of leukemia, percentage of blast cells, and karyotype） of the patients were performed. Results The PRAME gene was expressed in 38.2% of all 34 patients, in 40.7% of the patients with acute myelogenous leukemia （AML, n=27）, and in 28.6% of the patients with acute lymphoblastic leukemia （ALL, n=7）, but was not expressed in the healthy volunteers. The difference in the expression levels between AML and ALL patients was statistically significant. The rate of gene expression was 80% in M~, 33.3% in M2, and 28.6% in M~. Gene expression was also found to be correlated with CDl5 and CD33 expression and abnormal karyotype, but not with age, gender; white blood count or percentage of blast cells. Conclusions The PRAME gene is highly expressed in acute leukemia and could be a useful marker to monitor minimal residual disease. This gene is also a candidate target for the immunotherapy of acute leukemia.

Effect of siRNA targeting Ets2 gene on chemosensitization of human acute monocytic leukemic cell line SHI-1

Objective:This study was to observe the levels of Ets2 mRNA expression in leukemia patients and investigate the effect of small interfering RNA(siRNA)targeting Ets2 gene on sensibility of human acute monocytic leukemic cell line SHI-1 cells to etoposide(VP-16).Methods:Ets2 mRNA levels were determined by reverse transcription polymerase chain reaction(RT-PCR).After the transfection of Ets2 siRNA to SHI-1 cells by electroporation method,qRT-PCR was used to detect Ets2 gene expression in these cells;VP-16-induced apoptosis was investigated by Annexin V-FITC/PI.Results:Est2 mRNA was detectable in SHI-cells.The Est2 expression rate was respectively 10%in 5 healthy volunteers,60%in 5 acute lymphocytic leukemia(ALL)patients,73.68%in 19 acute nonlymphocytic leukemia(ANLL)patients and 100%in 4 chronic myeloid leukemia(CML)patients.The expression levels of Ets2 mRNA were significantly higher in leukemia patients compared with healthy volunteers.It also showed that siRNA targeting Ets2 gene resulted in substantial loss of Ets2 mRNA of SHI-1 cells compared to the control groups.Downregulation of Ets2 gene expression increased SHI-1 cells apoptosis and VP-16-induced apoptosis of SHI-1 cells.Conclusion:The high-level expression of Ets2 transcription factor in leukemia cells were connected with proliferation and anti-apoptosis of leukemia cells.SiRNA mediated Ets2 gene silencing induced cell apoptosis and enhanced in vitro sensitivity to chemotherapy(VP-16)of SHI-1 cells.It speculated the high-level expression of Ets2 may actually be an unfavorable determinant of chemotherapy sensitivity in leukemia.

DNA Methylation Analysis of Cassava （Manihotesculenta Crantz） SC8 and Its Autotetraploid in Response to Cold Stress

DNA methylation plays a vital role in the regulation of gene expression in response to environmental stress. However, little is known about the effect of DNA methylation on the cassava polyploidy. In the present study, methylation-sensitive amplified polymorphisms （MSAP） were used to investigate DNA methylation profiles of cassava polyploidy following cold treatment to identify candidate genes involved in response to cold stress. The result showed that the genome-wide DNA methylation polymorphisms accounted for 34.02%-42.56% in SC8 and its autotetraploid exposed to 5 ~C for 2, 8, 24 and 48 h, respectively. The methylation levels of SC8 at 2 h-cold stress were the highest during 48h under cold treatments. With the time extension within 48 h under cold stress, the methylation levels gradually decreased to the same level as the control but DNA methylation levels of cassava autotetraploid were stable within 48 h. For future analysis of the methylation extent, the cold stress induced more DNA methylation than demethylation in SC8, where DNA methylation was consistent with demethylation in its autotetraploid. The expression analysis demonstrated increase in the transcription of one methylated gene and decrease in the transcription of two demethylated genes. The results revealed that gene methylations in specific sites would be a rapidly epigenetic response to cold stress, further elucidating the methylation functions in its autotetraploid.

Reproductive toxicity assessment of benzo[a]pyrene in the marine polychaete Perinereis nuntia

Benzo[a]pyrene （B[a]P） is an increasingly present marine environmental pollutant, yet our understanding of the long-term consequences of reproductive toxicity in marine benthic polychaetes remains limited. To test the reproductive toxicity of B[a]P on polychaetes, Perinereis nuntia was exposed to B[a]P-contaminated artificial seawater and sexual maturation, the sex ratio, number of eggs spawned, fertilization and hatching rated, as well as vitellogenin （VTG） mRNA expression levels were analyzed. A low concentration of B[a]P （2.5 gg/L） had no effects on the rate of sexual maturation, spawning, or fertilization but significantly increased the sex ratio （female： male） from 1.6±0.15：1 to 2.3±0.18：1, inhibited hatching rate by 27%, and significantly increased VTG mRNA expression level by 3.7-fold following a 60-day exposure, compared with those in the solvent controls. A higher concentration of B[a]P （25 μg/L） caused more serious effects; sexual maturation, fertilization success, and hatching decreased by 31%, 17% and 46%, respectively, and the sex ratio （female： male） and VTG mRNA gene expression level increased by 54% and 7.1-fold, respectively. These results demonstrate that sublethal concentrations of B[a]P negatively affect reproductive performance of the sandworm P. nuntia.

Immunogenicity and virus-like particle formation of rotavirus capsid proteins produced in transgenic plants

The human pathogen, group A rotavirus, is the most prevalent cause of acute infantile and pediatric gastroenteritis worldwide, especially in developing countries. There is an urgent demand for safer, more effective and cheaper vaccines against rotavirus infection. Plant-derived antigens may provide an exclusive way to produce economical subunit vaccines. Virus-like particles, constituting viral capsid proteins without viral nucleic acids, are considered a far safer candidate compared with live attenuated viral vaccines. In this study, the rotavirus capsid proteins VP2, VP6 and VP7 were co-expressed in transgenic tobacco plants, and their expression levels, formation of rotavirus-like particles (RV VLPs) and immunogenicity were extensively studied. Quantitative real-time RT-PCR and Western blot analysis revealed that the expression level of vp6 was the highest while vp7 was expressed at the lowest levels. The RV VLPs were purified from transgenic tobacco plants and analyzed by electron microscopy and Western blot. Results indicated that the plant-derived VP2, VP6 and VP7 proteins self-assembled into 2/6 or 2/6/7 RV VLPs with a diameter of 60-80 nm. When orally delivered into mice with cholera toxin as an adjuvant, the total soluble protein extracted from transgenic tobacco plants induced rotavirus-specific antibodies comparable with those of attenuated rotavirus vaccines, while VP 2/6/7 induced higher serum IgG and fecal IgA titers compared with VP 2/6.