OBJECTIVETo observe the ability of triple helix-forming oligonucleotides (TFOs) modified with manganese porphyrin to combine with and cleave HBV DNA fractions.

METHODSTFO were modified with manganese porphyrin and acridines, and then reacted with the (32)P labeled HBV DNA fragments at 37 degrees C in vitro (pH 7.4). Electrophoretic mobility shift assays and DNase I footprinting tests were used to show the affinity and specificity of TFO to bind to target sequences. The ability of TFO to cleave HBV DNA fragments was tested by cleavage experiments.

RESULTSTFO modified with manganese porphyrin and acridine could bind to the target sequence in a sequence-dependent manner, with a Kd value of 3.5 x 10(-7) mol/L and a relative affinity of 0.008. In the presence of potassium monopersulfate (KHSO(5)), TFO modified with manganese porphyrin and acridine could cleave the target sequence where the triplex DNA was formed.

CONCLUSIONIn the presence of KHSO(5), TFO modified with manganese porphyrin and acridine could bind and cleave the target HBV-DNA in a sequence-dependent manner.

DNA ; drug effects ; pharmacology ; DNA, Viral ; chemistry ; drug effects ; Hepatitis B virus ; genetics ; Manganese ; pharmacology ; Metalloporphyrins ; pharmacology ; Potassium Compounds ; pharmacology ; Sulfates ; pharmacology

Objective: To reveal the crucial toxic components of ambient fine particles (PM_2.5) that affect the maturation and differentiation of megakaryocytes. Methods: Human megakaryocytes were exposed to the organic fractions, metallic fractions and water-soluble fractions of PM_2.5 at two exposure doses (i.e. actual air proportion concentration or the same concentration), respectively. The cell viability was performed to screen the non-cytotoxic levels of toxic components of PM_2.5 using the CCK-8 assay. CellTiter-Blue assay, morphological observation, flow cytometry analysis and WGA staining assay were used to evaluate the cell morphological changes, occurrence of DNA ploidy, alteration in the expressions of biomarkers and platelet formation, which were key indicators of the maturation and differentiation of megakaryocytes. Results: Compared to the control group, both metallic and organic components of PM_2.5 resulted in a lag in megakaryocytes with an increase in cell volume and the onset of DNA ploidy. Flow cytometry analysis showed that CD33 (the marker of myeloid-specific) decreased and CD41a (a megakaryocyte maturation-associated antigen) increased in metallic and organic components of PM_2.5 treatment groups. Moreover, compared to the control group, budding protrusions increased in metallic and organic components of PM_2.5 treatment groups. The water-soluble components had no effect on the maturation and differentiation of macrophages. Conclusion: Metallic and organic components of PM_2.5 are the crucial toxic components that promote the maturation and differentiation of megakaryocytes.
Biomarkers ; DNA/pharmacology* ; Humans ; Megakaryocytes/chemistry* ; Particulate Matter/toxicity* ; Sincalide/pharmacology* ; Water/pharmacology*

Aldehydes ; chemistry ; pharmacology ; Chromatography, High Pressure Liquid ; DNA Adducts

The damage to sperm DNA is one of the most important causes of male infertility. Some sperm with damaged DNA may escape from the sperm surveillance mechanism and transmit the damage to the offspring. So research on the damage to sperm DNA has become one of the hot spots in reproductive medicine. The factors that would damage sperm DNA include oxidative stress, microelements, reproductive toxic substances, radioactive rays, and so on, while the body depends on the compressed sperm DNA and anti-oxidation system for the protection of the integrity of sperm DNA. Some drugs such as anti-oxidant, black tea extract, etc, may help to improve and rebuild these protective mechanisms.
Antioxidants ; pharmacology ; DNA Damage ; DNA Repair ; physiology ; Humans ; Male ; Oxidative Stress ; Spermatozoa ; chemistry ; ultrastructure

OBJECTIVETo investigate the function of POLH(polymerase eta) through establishment of the POLH gene-blocked cell line FL-POLH(-).

METHODSA mammalian expression vector expressing antisense POLH gene fragment pMAMneo-amp-POLHA (-) was constructed by cloning the 1473 - 2131 fragment of POLH gene into the mammalian expression vector pMAMneo-amp(-) in antisense orientation. The FL cells were transfected with this antisense RNA expressing vector and selected by G418. The mutation assay was conducted using the shuttle plasmid pZ189.

RESULTThe spontaneous mutation frequency of SupF tRNA gene in the plasmid replicated in the FL-POLH(-) was 13.5 x 10(-4), while it was 4.9x10(-4) and 3.7x10(-4) in the control cells FL and FL-M, respectively. The nontargeted mutation frequency of SupF tRNA gene decreased in the plasmid replicated in these cell lines pretreated with MNNG.

CONCLUSIONPOLH plays an important role in maintenance of genetic stability and genesis of nontargeted mutation.

Antisense Elements (Genetics) ; pharmacology ; Cell Line ; DNA-Directed DNA Polymerase ; genetics ; physiology ; Methylnitronitrosoguanidine ; toxicity ; Mutagenesis

OBJECTIVETo investigate the expression and analysis of its activity of anti-bacterial peptide gloverin in COS-7 cells.

METHODSThe appearance frequency of all genetic codes in the cDNA sequence from the same species of protein Attacin A was analyzed, and its cDNA sequence was synthesized by PCR overlapping extension method in conjunction with the designation of the known protein sequence of gloverin. The genes were inserted into pCDSI, an eukaryotic vector, after being identified correctly. As a result, the vector pBZHG was constructed. Thereafter, the liposome FuGENE( trade mark ) 6 was employed as the vector, and the COS-7 cells were transfected with liposome pBZHG and blank vector pCDSI. The normal cells were taken as the control. The supernatant was collected for the detection of its bactericidal activity after 72 PBHs.

RESULTSThe gloverin cDNA sequence designed artificially was expressed in COS-7 cells. The supernatant of the cells transfected by pBZHG exhibited bactericidal activity to E. coli J5 when compared with that from normal cells and in cells transfected with blank vectors.

CONCLUSIONThe designed cDNA sequence of gloverin was proved to be genuine, and it provided the basis for future study of its antibiotic and anti-endotoxin activities.

Animals ; Anti-Bacterial Agents ; pharmacology ; COS Cells ; Cercopithecus aethiops ; Proteins ; genetics ; pharmacology ; Sequence Analysis, DNA ; Transfection

OBJECTIVETo confirm that arsenic (As) induces oxidative DNA damage in phytohemagglutinin (PHA)-stimulated and unstimulated human lymphocytes.

METHODSThe alkaline comet assay combined with specific enzyme (Formamidopyrimidine-DNA glycosylase, FPG) digestion was used to measure As-induced base damage.

RESULTSThe enzyme-sensitive sites were readily detected with the alkaline comet assay after the cells were treated with 10 micromol As for 2 hours. The repair patterns observed for FPG-created DNA single strand breaks (SSBs) in As-treated cells were comparable to those in hydrogen peroxide (H(2)O(2))-treated cells. The enzyme-created SSBs, As-induced base damage, were more significantly revealed in PHA-stimulated lymphocytes. About 63% and 68% of SSBs induced by As and H(2)O(2), respectively, were repaired in PHA-stimulated lymphocytes by 2-hour repair incubation, but about 34% and 43%, respectively, were repaired in unstimulated cells. About 40% and 49% of base damage induced by As and H(2)O(2), respectively, were repaired in PHA-stimulated lymphocytes, but about 19% and 21 %, respectively, were repaired in unstimulated cells.

CONCLUSIONSAs induces oxidative DNA damage in human lymphocytes within micromolar concentrations. Like the damage induced by H(2)O(2), As-induced DNA damage was more slowly repaired in unstimulated lymphocytes.

Adult ; Arsenic ; pharmacology ; DNA Damage ; DNA Repair ; DNA, Single-Stranded ; drug effects ; DNA-Formamidopyrimidine Glycosylase ; Electrophoresis ; methods ; Humans ; Hydrogen Peroxide ; pharmacology ; Lymphocytes ; drug effects ; N-Glycosyl Hydrolases ; Oxidation-Reduction ; Phytohemagglutinins ; pharmacology

OBJECTIVETo study the effect of triptolide (TP) on the methylation status of human promyelocytic leukemia cells (HL-60) and explore a preliminary demethylation mechanism.

METHODSNormal HL-60 cells as control group, the cell proliferation level of HL-60 cells was detected by MTT assay, being treated by different concentration TP (3.125, 6.25, 12.5, 25 nmol/L) for 24 h or 48 h respectively; Choosing the 3.125 nmol/L and the 6.25 nmol/L TP affected HL-60 cells for 48 h, the cell apoptosis rate and cell cycle were determined by flow cytometry, the expressions of death-associated protein kinase 1 (DAPK-1) and methyltransferase DNMT1, DNMT3B mRNA were measured by real time-PCR (RT-PCR), LINE-1, DAPK-1 genes'methylation variations were analyzed by methylation specific PCR (MSP).

RESULTSCompared with control group, the different concentration TP could significantly inhibit the proliferation of HL-60 in a time-dose dependent manner (P<0.05, P<0.01). After being treated by TP for 48 h, the cell early apoptosis rate of control group and 6.250 nmol/L TP group were (2.07 ± 1.91)%, (9.77 ± 3.52)%, respectively (P<0.05); When the TP concentration increased, DAPK-1mRNA expression increased (P<0.01), DNMT1, DNMT3B mRNA expression significantly dampened (P<0.01); the promoter of LINE-1, DAPK-1 genes were hypermethylation state in the control group, after being treated by TP for 48 h, the brightness of LINE-1, DAPK-1 genes'methylation strips weakened, and the non-methylation strips enhanced all in a dose-dependent manner.

CONCLUSIONTP could down-regulate the transcriptional expression of methyltransferase DNMT1/3B genes, indirect action to reduce the degree of DAPK-1, LINE-1 genes mathylation, thus promote DAPK-1 gene expression level and inhibit the HL 60 cell growth.

DNA (Cytosine-5-)-Methyltransferases ; DNA Methylation ; drug effects ; Death-Associated Protein Kinases ; Diterpenes ; pharmacology ; Epoxy Compounds ; pharmacology ; HL-60 Cells ; Humans ; Phenanthrenes ; pharmacology ; Promoter Regions, Genetic ; RNA, Messenger

Objective: To clarify the roles of yam polysaccharide (YPS) in improving sperm viability and protecting sperm DNA integrity in vitro and provide a new approach to the treatment of oligoasthenozoospermia. METHODS: We collected samples by masturbation from 36 normal fertile males aged 27－39 years. Each sample was divided into six groups: blank control or treated with normal saline, vitamin C solution, and YPS solution at low (0.25 mg/ml), medium (1.0 mg/ml) or high concentration (5.0 mg/ml). Using eosin-Y staining, sperm hypotonic swelling (HOS) and sperm chromatin diffusion (SCD) test, we observed the effects of different concentrations of YPS on sperm viability, membrane integrity and nuclear DNA. RESULTS: After 24 and 48 hours of treatment, sperm viability was markedly reduced in the vitamin C (［28.5 ± 3.1］ and ［6.5 ± 1.2］%), low-YPS (［31.3 ± 3.5］ and ［6.5 ± 2.2］%), medium-YPS (［37.1 ± 3.5］ and ［9.5 ± 2.8］%) and high-YPS groups (［38.3 ± 3.3］ and ［9.0 ± 3.2］%) as compared with the blank control (［17.3 ± 2.1］ and ［3.2 ± 1.3］%) (P <0.01) and normal saline groups (［13.4 ± 4.1］ and ［3.1 ± 2.0］%) (P <0.01), and it was significantly higher in the medium- and high-YPS than in the vitamin C group (P <0.05 and P <0.01). The rate of sperm DNA fragmentation was remarkably decreased at 48 hours in the vitamin C (［30.5 ± 3.1］%), low-YPS (［29.4 ± 2.6］%), medium-YPS (［28.5 ± 2.3］%) and high-YPS groups (［27.9 ± 1.9］%) in comparison with the blank control (［41.7 ± 2.2］%) (P <0.01) and normal saline groups (［42.1 ± 3.3］%), markedly lower in the medium- and high-YPS than in the blank control, normal saline and vitamin C groups (P <0.05 or P <0.01), but with no statistically significant difference between the low-YPS and vitamin C groups (P >0.05). CONCLUSIONS Yam polysaccharide can improve sperm viability and protect sperm DNA integrity in vitro.
Adult ; Ascorbic Acid ; pharmacology ; DNA ; drug effects ; DNA Fragmentation ; Dioscorea ; chemistry ; Humans ; Male ; Polysaccharides ; pharmacology ; Semen Analysis ; Sperm Motility ; Spermatozoa ; drug effects ; physiology ; Vitamins ; pharmacology

OBJECTIVETo observe the release of DNA from Pseudomonas aeruginosa (P. aeruginosa) induced by different concentrations of piperacillin/tazobactam (Piper) in vitro.

METHODSThe minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of Piper against 1244 strain (ATCC 27317) of P. aeruginosa were determined, respectively. This strain of P. aeruginosa was separately cultured with Piper in different concentrations at 37 degrees C for 4 h and 24 h. The samples of cultural supernatant were filtered and electrophoresis was conducted in 1.8% agarose with SYBR Gold stain. Then the images of the gel sheets were photographed.

RESULTSThis strain of P. aeruginosa was sensitive to Piper. The bacterial DNA was not detected in 4-h cultured P. aeruginosa either with or without Piper by this method. The bacterial DNA molecules could be detected in 24 h samples in cultures without Piper, and they were displayed in two zones of molecular weight over 2000 base pairs (bp) and lower than 100 bp. Similar results were observed when the MIC of piper (0.002, 0.004 g/L) were under the MIC measured at the 3rd time (0.008 g/L), but there was much more bacterial DNA with molecular weight lower than 100 bp. When Piper concentration was higher than its MIC, only smaller quantities of bacterial DNA in the area with molecular weight lower than 400 bp could be detected in 24-h culture samples.

CONCLUSIONA certain amount of bacterial DNA was released from P. aeruginosa under its natural growth circumstance. Different concentrations of Piper showed different effects on DNA release, in regard to its quantity and molecular weight, from P. aeruginosa cultures.

Anti-Bacterial Agents ; pharmacology ; DNA, Bacterial ; metabolism ; Penicillanic Acid ; analogs & derivatives ; pharmacology ; Piperacillin ; pharmacology ; Pseudomonas aeruginosa ; drug effects ; metabolism