OBJECTIVETo study the urinary excretion pattern for of 2-thio-thiazolidine-4-carboxylic acid (TTCA) in workers exposed to CS2, so as to provide experimental basis for working out biomonitoring measures for short-term exposure to CS2.

METHODSSixty-nine subjects were divided into three groups: (1) fourteen volunteers who had not been exposed to CS2 before were exposed to CS2 for 2 hours, their urine samples were collected and analyzed at different time points; (2) The urine samples of 15 occupational exposure workers were collected on pre-shift, mid-shift, post-shift; (3) The relationship between 8 h time weighted average CS2 exposure concentrations (PC-TWA) and TTCA levels of post-shift urine was studied among 40 workers chronically exposed to CS2.

RESULTS(1) In the 1st group, urine TTCA level reached the peak [(1.03 +/- 0.72) mg/gCr] 4 h after exposure; (2) In the 2nd group, urine TTCA level on pre-shift [(0.37 +/- 0.28) mg/gCr] was lower than that on mid-shift [(1.23 +/- 0.71) mg/gCr, P<0.01] and post-shift [(1.31 +/- 0.78) mg/gCr, P<0.01]; (3) In the 3rd group, there was a linear relationship between the post-shift urine TTCA level and 8 h CS2 exposure concentrations dose (PC-TWA). The regression equation is Y(TTCA mg/gCr)=1.163 6X(CS2 mg/m3)-5.411 6.

CONCLUSIONThe post-shift urine TTCA levels may be regarded as a bio-monitoring index for workers exposed to CS2.

Adult ; Carbon Disulfide ; metabolism ; Environmental Monitoring ; Humans ; Male ; Middle Aged ; Occupational Exposure ; Thiazoles ; urine ; Thiazolidines

The present study was designed to investigate the effects of start codon of nosM on the biosynthesis of nosiheptide. Target genes were amplified by overlap PCR. After homologous recombination to construct engineered strains, nosiheptide production was analyzed by HPLC. Three mutants with different start codon of nosM were constructed, and nosiheptide production of each mutant was analyzed and compared. Replacement of the start codon of nosM significantly decreased the production of nosiheptide. In conclusion, start codon usage could greatly affect the biosynthetic efficiency in the biosynthetic gene cluster of nosiheptide.
Anti-Bacterial Agents ; biosynthesis ; Chromatography, High Pressure Liquid ; Codon, Initiator ; Escherichia coli ; Genes, Bacterial ; Mutation ; Streptomyces ; genetics ; metabolism ; Thiazoles ; metabolism

The objective of this study is to propose a more accurate and faster MTT [3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide] colorimetric assay (MCA) for quantitative measurement of polypeptide bacteriocins in solutions with nisin as an example. After an initial incubation of nisin and indicator bacterium Micrococcus luteus NCIB 8166 in tubes, MTT was added for another incubation period. After that, nisin was quantified by estimating the number of viable bacteria based on measuring the amount of purple formazan produced by cleavage of yellow tetrazolium salt MTT. Then MCA was compared to a standard agar diffusion assay (ADA). The results suggested a high correlation coefficient (r(2)=0.975+/-0.004) between optical density (OD) and the inhibitory effect of nisin on a bacterial strain Micrococcus luteus NCIB 8166 at a range of 0.125-32 IU/ml. The MCA described in this study was very quick. Quantification of nisin took only 7-8 h and the detection limit was at the level of 0.125 IU/ml when compared to 12 IU/ml and 24-28 h for ADA. The MCA provides an accurate and rapid method for quantification of nisin in solutions and is expected to be used for quantification of other antimicrobial substances.
Bacteriocins ; analysis ; metabolism ; Colorimetry ; methods ; Immunodiffusion ; Micrococcus luteus ; metabolism ; Nisin ; Regression Analysis ; Tetrazolium Salts ; analysis ; Thiazoles ; analysis ; Time Factors

A series of novel 2-amino-4-phenylthiazole derivatives were designed and synthesized, furthermore, their inhibition effect on acetylcholinesterase were investigated. 2-Amino-4-phenylthiazoles were prepared from alpha-bromoacetophenones by Hantzsch reaction, acylation reaction and substitution reaction. Moreover, their bioactivities as AChE inhibitors in vitro were measured with Ellman spectrophotometry. The results showed that most of them had a certain inhibition activity on AChE, and the compound 8a was the best of them. The IC50 of 8a to AChE is 3.54 micromol x L(-1), and the value was better than that of rivastigmine. 2-Amino-4-phenylthiazole derivatives showed a certain bioactivity in vitro, which were worth further investigation.
Acetylcholinesterase ; metabolism ; Cholinesterase Inhibitors ; chemical synthesis ; chemistry ; pharmacology ; Drug Design ; Inhibitory Concentration 50 ; Molecular Structure ; Thiazoles ; chemical synthesis ; chemistry ; pharmacology

AIMTo synthesize a series of 2-arylimino-4-thiazolidone derivatives and 2-imidazolino [2,3-b]-4-thiazolidone in order to get some novel potent compounds with nitric oxide synthases (NOS) inhibitory activity.

METHODSThe target compounds were prepared by reaction of N-chloroacetyl-1,2,3,4-tetrahydroisoquinoline or N-chloroacetylphthalimide with substituted thioureas, their NOS inhibitory activity were measured.

RESULTS AND CONCLUSIONThe 15 new compounds were synthesized and most of the reaction yields were over 65%. The structures of new compounds were identified by IR, 1H NMR, MS and elemental analyses. Bioassay indicated that, most of 15 new compounds synthesized had confirmed bioactivities inhibition against NOS.

Molecular Structure ; Nitric Oxide Synthase ; antagonists & inhibitors ; metabolism ; Structure-Activity Relationship ; Thiazoles ; chemical synthesis ; chemistry ; pharmacology ; Thiourea ; analogs & derivatives

In order to establish a new more rapid, safe and sensitive colorimetric assay for the proliferation of leukemic cells, MTS/pms has been developed. This automated colorimetric assay is based on the characteristic of viable and metabolically active leukemic cells to cleave MTS/pms into a water-soluble product whose optical density is determined at 492 nm by an automated microtiter-plate reader photometer. The results indicated that only active leukemic cells cleaved MTS/pms into product measured, and dead cells did not reduce MTS/pms. A linear relations hip were found between the viable cell number and optical density of MTS/pms cleaved by HL-60 and K562 cell (r = 0.963). Compared with MTT and INT assays, the reduced product of MTS/pms is water-soluble. It is concluded that MTS/pms colorimetric assay is more rapid, accurate and sensitive for the bioassay of proliferation of leukemic cells.
Cell Division ; Colorimetry ; methods ; Formazans ; metabolism ; HL-60 Cells ; Humans ; K562 Cells ; Leukemia ; pathology ; Methylphenazonium Methosulfate ; metabolism ; Tetrazolium Salts ; metabolism ; Thiazoles ; metabolism

OBJECTIVETo investigate the effects of cycle-dependent kinase (CDK) inhibitor SNS-032 on apoptosis in human acute myeloid leukemia (AML) HL-60 cells and its molecular mechanisms.

METHODSCultured AML HL-60 cells were treated with various concentrations of SNS-032. Cell apoptosis was determined with flow cytometry;cell viability was measured by MTT assay; the profiles of microRNA expression of HL-60 cells were analyzed by microRNA microarray;the protein expressions of JAK2/STAT3 pathway were detected by Western blotting.

RESULTSApoptosis of AML HL-60 cells was induced by SNS-032; the rate of apoptosis was (5.9±1.7)%, (12.1±3.1)% and (59.4±3.6)% when HL-60 cells were treated with 0,100 and 200 nmol/L SNS-032. MicroRNA microarray analysis revealed that the levels of miR-30a, miR-183, miR-20b, miR-26b, miR-20a, miR-589, miR-107, miR-181a, miR-106a, miR-17 and miR-378c were down-regulated by SNS-032,whereas the levels of miR-320a and miR-H7* were up-regulated. Western blotting showed that SNS-032 strongly inhibited phosphorylation of STAT3 and protein expression of JAK2,C-MYC and MCL-1.

CONCLUSIONCDK inhibitor SNS-032 can induce apoptosis of AML HL-60 cells, which is associated with the inhibition of MCL-1,C-MYC and JAK2/STAT3, and down-regulation of miR-17-92 family.

Apoptosis ; Cell Survival ; Down-Regulation ; Flow Cytometry ; HL-60 Cells ; Humans ; Janus Kinase 2 ; metabolism ; MicroRNAs ; metabolism ; Oxazoles ; pharmacology ; Phosphorylation ; STAT3 Transcription Factor ; metabolism ; Signal Transduction ; Thiazoles ; pharmacology

Cardiac dysfunctions such as myocardial functional failure and ventricular arrhythmia have been largely attributed to intracellular Ca2+ overload. One of the mechanisms of intracellular Ca2+ overload involves a rapid influx of Ca2+ via Na(+)-Ca2+ exchange during the reperfusion which utilizes the accumulation of Na+ in myocytes during ischemic cardiac arrest. Possible sources of the intracellular Na+ accumulation include Na+ channel, Na(+)-H+ exchange, Na(+)-Ca2+ exchange, and Na+ background current. In this study, we studied the role of the Na+ background current in intracellular Na+ accumulation during the cardiac arrest by measuring the Na+ background current in guinea pig ventricular myocytes with whole cell clamp method and evaluating the effects of cardioprotective drugs on the Na+ background current. The results were as follows: (1) The Na+ background inward current at -40 mV membrane potential was larger at Ca2+ free solution than 1.8 mM Ca2+ solution. (2) The Na+ background current was not affected by verapamil. (3) 2 microM O-(N, N-hexamethylene)-amiloride (HMA) decreased the Na+ background current at negative membrane potential. (4) The new cardioprotective drug, R 56865, decreased the Na+ background current. These results suggest that the Na+ background current plays a role in increasing the intracellular Na+ activity during high K+ cardioplegia and the blocking effect of myoprotective drugs, such as R 56865, on the Na+ background current may contribute to myocardial protection after cardioplegia.
Amiloride/pharmacology ; Animal ; Guinea Pigs ; Heart/*drug effects ; Heart Arrest, Induced ; Myocardium/metabolism ; Piperidines/pharmacology ; Potassium/pharmacology ; Sodium/*metabolism ; Support, Non-U.S. Gov't ; Thiazoles/pharmacology ; Verapamil/pharmacology

BACKGROUNDTo investigate the dynamics of amyloid fiber formation of yeast (Saccharomyces cerevisiae) prion protein Sup35NM under the native condition to provide materials and clues for the elucidation of amyloid fiber formation.

METHODSThe Sup35NM gene was cloned and expressed in E. coli. The recombinant Sup35NM protein was purified under denaturing conditions through Nickel-Sepharose chromatography. Aliquots were removed at designated time points for transmission electron microscopy (TEM), circular dichroism (CD) spectra, protease K resistance assay, as well as thioflavin T (ThT) binding assay.

RESULTSThe Sup35NM expressed and purified under denaturing conditions. The morphological alteration of the Sup35NM in PBS (pH7.4) during the protein aggregation and amyloid fiber formation was visualized by TEM. The CD assay showed that the course of amyloid fiber formation underwent a conformational shift from alpha-helix to beta-sheet. The fibers had higher capacity of resistance to protease K digestion compared to the monomers. ThT fluorescence assay displayed a rapid growth phase before reaching a final equilibrium phase during the fiber formation, and the higher concentration of Sup35NM could greatly accelerate the fiber formation in vitro.

CONCLUSIONYeast prion protein Sup35NM forms amyloid readily under native conditions in vitro. The dynamics of Sup35NM amyloid formation may provide supporting evidences for the nucleating polymerization models of amyloid fiber formation.

Amyloid beta-Peptides ; genetics ; metabolism ; ultrastructure ; Electrophoresis, Polyacrylamide Gel ; Endopeptidase K ; metabolism ; Kinetics ; Microscopy, Electron ; Peptide Termination Factors ; Prions ; genetics ; metabolism ; ultrastructure ; Protein Binding ; Recombinant Proteins ; metabolism ; ultrastructure ; Saccharomyces cerevisiae ; genetics ; metabolism ; Saccharomyces cerevisiae Proteins ; genetics ; metabolism ; ultrastructure ; Thiazoles ; metabolism

Alzheimer Disease ; metabolism ; pathology ; Amyloid beta-Peptides ; metabolism ; Animals ; Brain ; metabolism ; pathology ; Cerebral Amyloid Angiopathy ; metabolism ; pathology ; Fluorescent Dyes ; chemistry ; Humans ; Mice ; Peptide Fragments ; metabolism ; Staining and Labeling ; Thiazoles ; chemistry