The aim and novelty of this paper are found in assessing the influence of inhibitors and antibiotics on intact cell MALDI-TOF mass spectra of the cyanobacterium Synechococcus sp. UPOC S4 and to check the impact on reliability of identification. Defining the limits of this method is important for its use in biology and applied science. The compounds included inhibitors of respiration, glycolysis, citrate cycle, and proteosynthesis. They were used at 1-10 μM concentrations and different periods of up to 3 weeks. Cells were also grown without inhibitors in a microgravity because of expected strong effects. Mass spectra were evaluated using controls and interpreted in terms of differential peaks and their assignment to protein sequences by mass. Antibiotics, azide, and bromopyruvate had the greatest impact. The spectral patterns were markedly altered after a prolonged incubation at higher concentrations, which precluded identification in the database of reference spectra. The incubation in microgravity showed a similar effect. These differences were evident in dendrograms constructed from the spectral data. Enzyme inhibitors affected the spectra to a smaller extent. This study shows that only a long-term presence of antibiotics and strong metabolic inhibitors in the medium at 10-5 M concentrations hinders the correct identification of cyanobacteria by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF).

• MeSH
• Anti-Bacterial Agents toxicity   MeSH
• Antimycin A analogs & derivatives   toxicity   MeSH
• Azides toxicity   MeSH
• Cell Respiration drug effects   MeSH
• Chloramphenicol toxicity   MeSH
• Citric Acid Cycle drug effects   MeSH
• Deoxyglucose toxicity   MeSH
• Fluoroacetates toxicity   MeSH
• Glycolysis drug effects   MeSH
• Malonates toxicity   MeSH
• Protein Biosynthesis drug effects   MeSH
• Pyruvates toxicity   MeSH
• Reproducibility of Results MeSH
• Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization methods   MeSH
• Weightlessness MeSH
• Streptomycin toxicity   MeSH
• Synechococcus chemistry   drug effects   isolation & purification   metabolism   MeSH
• Publication type
• Journal Article MeSH

A compound with promising anticancer properties, 3-bromopyruvate (3-BP) is a synthetic derivative of a pyruvate molecule; however, its toxicity in non-malignant cells has not yet been fully elucidated. Therefore, we elected to study the effects of 3-BP on primary hepatocytes in monolayer cultures, permeabilized hepatocytes and isolated mitochondria. After a 1-h treatment with 100 μM 3-BP cell viability of rat hepatocytes was decreased by 30 % as measured by the WST-1 test (p < 0.001); after 3-h exposure to ≥200 μM 3-BP lactate dehydrogenase leakage was increased (p < 0.001). Reactive oxygen species production was increased in the cell cultures after a 1-h treatment at concentrations ≥100 μmol/l (p < 0.01), and caspase 3 activity was increased after a 20-h incubation with 150 μM and 200 μM 3-BP (p < 0.001). This toxic effect of 3-BP was also proved using primary mouse hepatocytes. In isolated mitochondria, 3-BP induced a dose- and time-dependent decrease of mitochondrial membrane potential during a 10-min incubation both with Complex I substrates glutamate + malate or Complex II substrate succinate, although this decrease was more pronounced with the latter. We also measured the effect of 3-BP on respiration of isolated mitochondria. ADP-activated respiration was inhibited by 20 μM 3-BP within 10 min. Similar effects were also found in permeabilized hepatocytes of both species.

• MeSH
• Time Factors MeSH
• Hepatocytes cytology   drug effects   ultrastructure   MeSH
• Mitochondria, Liver drug effects   MeSH
• Rats MeSH
• Cells, Cultured MeSH
• Membrane Potential, Mitochondrial drug effects   MeSH
• Mitochondrial Diseases chemically induced   physiopathology   MeSH
• Mice MeSH
• Pyruvates pharmacology   toxicity   MeSH
• Reactive Oxygen Species metabolism   MeSH
• Cell Survival drug effects   MeSH
• Dose-Response Relationship, Drug MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH