Apoptosis ; drug effects ; Arsenicals ; pharmacology ; Cell Line, Tumor ; drug effects ; Drug Resistance, Neoplasm ; drug effects ; Humans ; Oxides ; pharmacology ; Point Mutation

OBJECTIVETo determine the optimal concentration and processing time of EMS mutation for suspension cells from Pinellia ternata.

METHODUnder four EMS concentration gradients (0.1% , 0.2%, 0.4%, 0.6%) and three processing time gradients (0.5, 1.0, 2.0 h), the suspension cells of P. ternata were mutagenized.

RESULT AND CONCLUSIONThe results showed that the survival rate was significantly different under the different concentrations of EMS and the different processing time. In the same processing time, the EMS concentrations were increased, but the suspension cells survival rate decreased gradually. The optimum EMS concentration for the mutagenesis was 0.4% and the best processing time was 1 hour.

Cell Survival ; drug effects ; genetics ; Dose-Response Relationship, Drug ; Ethyl Methanesulfonate ; pharmacology ; Mutagenesis ; drug effects ; Mutation ; drug effects ; Pinellia ; cytology ; drug effects ; genetics ; physiology ; Suspensions ; Temperature ; Time Factors

Aged ; China ; Drug Resistance, Bacterial ; Humans ; L Forms ; drug effects ; Middle Aged ; Mining ; Mutation ; Mycobacterium tuberculosis ; drug effects ; Silicotuberculosis ; microbiology

Pyrazinamide (PZA) is one of the most important drugs for the treatment of Mycobacterium tuberculosis infection. However, the increasing frequency of PZA-resistant strains limits its effectiveness. In Korea, most PZA-resistant strains also exhibit both isoniazid and rifampin resistance making it essential to identify these resistant strains accurately and rapidly for effective treatment of mycobacterial infection. In this study, the characteristics and frequency of mutations of the pncA gene encoding pyrazinamidase were investigated in PZA-resistant clinical isolates from Korea. Automated DNA sequencing was used to evaluate the usefulness of DNA-based detection of PZA resistance. Among 95 PZA-resistant clinical isolates, 92 (97%) exhibited mutations potentially affecting either the production or the activity of the enzyme. Mutations were found throughout the pncA gene including the upstream region. Single nucleotide replacement appeared to be the major mutational event (69/92), although multiple substitutions as well as insertion and deletion of nucleotides were also identified. The high frequency of pncA mutations observed in this study supports the usefulness of DNA-based detection of PZA-resistant M. tuberculosis. Having verified the scattered and diverse mutational characteristics of the pncA gene, automated DNA sequencing seems to be the best strategy for rapid detection of PZA-resistant M. tuberculosis.
Amidohydrolases/*genetics ; Antitubercular Agents/*pharmacology ; Drug Resistance, Bacterial ; *Mutation ; Mycobacterium tuberculosis/*drug effects/genetics ; Pyrazinamide/*pharmacology

Drug Resistance, Viral ; genetics ; Hepatitis B virus ; drug effects ; genetics ; Mutation

Drug Resistance, Viral ; genetics ; Hepatitis B virus ; drug effects ; genetics ; Mutation ; Nucleosides ; pharmacology

OBJECTIVETo investigate the cyto-genotoxicity of cigarette smoke condensates (CSCs) in human peripheral blood lymphocytes with different assays in vitro.

METHODSHuman lymphocytes were exposed to particle matter of cigarette smoke combined with or without S9 mixtures at doses of 25, 50, 75, 100 and 125 microg/ml for 3 h. The cytotoxicity induced by CSCs was detected by CCK-8 assay. The DNA damage, DNA repair (repair time: 30, 60, 90, 120 and 240 min, respectively) and the somatic cell mutations induced by 75 microg/ml CSCs were measured by comet assay, hprt gene and TCR gene mutation tests, respectively.

RESULTSCCK-8 assay indicated that the cell viability decreased with CSCs doses. At the doses of 100, 125 microg/ml, the cell viability of CSCs +S9 group was significantly higher than that of CSCs -S9 group (P < 0.05, P < 0.01). In comet assay, DNA damage significantly increased in a dose-dependent manner, as compared with controls (P < 0.01). Moreover, there was significant difference between -S9 group and +S9 group (P < 0.05, P < 0.01). The Mf-TCR at each dose group was significantly higher than that of controls (P < 0.05, P < 0.01). The Mf-hprt at high-dose groups were significantly higher than that of controls (P < 0.01), and significant difference of Mf-TCR and Mf-hprt at high doses of CSCs between -S9 group and +S9 group (P < 0.05, P < 0.01). The DNA damage induced by CSCs +S9 or CSCs -S9 could be repaired, but DNA repair speed was different between -S9 group and +S9 group (P < 0.05, P < 0.01).

CONCLUSIONCSCs may induce cyto-genotoxicity in human peripheral blood lymphocytes in vitro, but S9 mix could reduce the toxicity of CSCs and impact DNA repair speed.

Cells, Cultured ; Comet Assay ; DNA Damage ; drug effects ; DNA Repair ; drug effects ; Humans ; Lymphocytes ; drug effects ; Male ; Mutation ; Tobacco Smoke Pollution ; adverse effects ; Young Adult

OBJECTIVETo assess the genetic damage of human B lymphocyte cell line induced by 14 nm and 280 nm carbon black (CB) particles with micronucleus assay (CBMN), comet assay and hprt gene mutation test in vitro.

METHODSThe genetic damage of human B lymphocyte cells exposed to 14 nm and 280 nm CB particles at the doses of 0, 128, 256, 384 and 512 microg/ml for 24 h and 48 h was detected using above three genotoxic assays. Micronucleus (MN) assay, comet assay, hprt gene mutation test were used to detect the genetic damage of human B lymphocyte cells induced by CB. Micronucleus rate (MNR), micronucleated cell rate (MCR), nuclear buds (Buds), nucleoplasmic bridges (NPBs), nuclear division index (NDI) and numbers of apoptotic cells served as indexes of CBMN assay; the percentage of DNA in the tail (% tail DNA) and the olive tail moment (OTM) were used as DNA damage indicators of comet assay; the hprt gene mutation frequency (Mf-hprt) served as the index of hprt gene mutation test.

RESULTSThe % tail DNA, OTM in 14 nm CB group at the doses of 384 and 512 microg/ml for 48 h were 8.23% +/- 0.19%, 11.23% +/- 0.42% and 3.72 +/- 0.08, 4.90 +/- 0.18, respectively, which were significantly higher than those in control (5.10% +/- 0.08% and 2.22 +/- 0.03) (P < 0.01). The apoptotic cell rates in 14 nm CB group at the doses of 384 and 512 microg/ml for 48 h were 4.67 +/- 0.33 and 5.33 +/- 0.33, respectively, which were significantly higher than in control (0.00 +/- 0.00) (P < 0.05). The results of Mf-hprt were negative.

CONCLUSIONThe genetic damage of human B lymphocyte cells exposed to 14 nm CB particles for 48 h could be detected. But the similar effects didn't appear in 280 nm CB group.

B-Lymphocytes ; drug effects ; Cell Line ; Comet Assay ; DNA Damage ; drug effects ; Humans ; Micronucleus Tests ; Mutation Rate ; Soot ; toxicity

AIMTo study the sodium nitrite induced DNA mutation by convolution spectrometry (CS).

METHODSThe spectra of sodium nitrite-induced mutative calf thymus DNA was compared with ego criteria based on Spectra of the primary DNA within the wavelength range from 200 to 340 nm. Distilled water served as blank and normal saline served as negative control. Any difference was quantitatively expressed by differential value (delta) of convolution spectra. Near-infrared spectroscopy was employed as the reference method.

RESULTSThe differential value was positively correlated with the increasing time and concentration of sodium nitrite. delta values increased to 1.37%, 2.41% and 5.44% respectively within 2-hour's reaction between calf thymus DNA and 0.5, 0.05 and 0.005 microgram.mL-1 sodium nitrite, while on the contrary, changes could be hardly observed on the corresponding UV absorption spectra. The results were also confirmed by their corresponding near-infrared spectra.

CONCLUSIONThe delta values can be used to represent the compound's strength of mutagenesis. Every convolution procedure takes less than one minute, so CS provides a fast, simple and inexpensive alternative method to determine chemical or medicinal DNA mutation.

Animals ; Cattle ; DNA ; chemistry ; drug effects ; In Vitro Techniques ; Mutation ; drug effects ; Sodium Nitrite ; pharmacology ; Spectrum Analysis ; methods ; Thymus Gland ; chemistry ; drug effects

Adult ; Carcinogens ; Epoxy Compounds ; poisoning ; Female ; Humans ; Lymphocytes ; drug effects ; metabolism ; Male ; Multivariate Analysis ; Mutation ; drug effects ; Occupational Exposure ; analysis ; Regression Analysis ; Sister Chromatid Exchange ; drug effects