The goal of this study was to contribute to understanding of the mechanisms behind sensitivity differences between early and late instar larvae of Chironomus riparius and to address the influence of the differences in standard testing approaches on the toxicity evaluation. A 10-day contact sediment toxicity test was carried out to assess sensitivity to cadmium exposure in relation to different age and laboratory culture line origin of test organisms. Chironomid larvae of early (OECD 218 method) and late instar (US-EPA600/R-99/064 method) differed substantially in sensitivity of traditional endpoints (OECD: LOEC 50 and 10 μg Cd/g dry weight (dw); US-EPA: LOEC > 1000 and 100 μg Cd/g dw for survival and growth, respectively). Bioaccumulated cadmium and metallothioneins (MTs) concentrations were analyzed to investigate the role of MTs in reduced sensitivity to cadmium in late instar larvae. Metallothioneins were induced after treatment to greater Cd concentrations, but their levels in relation to cadmium body burdens did not fully explain low sensitivity of late instars to cadmium, which indicates some other effective way of detoxification in late instars. This study brings new information related to the role of MTs in age-dependent toxicant sensitivity and discusses the implications of divergence in data generated by chironomid sediment toxicity tests by standardized methods using different instars.

• Klíčová slova
• Artificial sediment, Bioaccumulation, Cadmium, Chironomus, Metallothionein,
• MeSH
• Chironomidae účinky léků   MeSH
• kadmium toxicita   MeSH
• larva účinky léků   MeSH
• metalothionein analýza   metabolismus   MeSH
• testy toxicity MeSH
• vystavení vlivu životního prostředí MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• kadmium MeSH
• metalothionein MeSH

Increasing urbanization and industrialization lead to the release of metals into the biosphere, which has become a serious issue for public health. In this paper, the direct electrochemical reduction of zinc ions is studied using electrochemically reduced graphene oxide (ERGO) modified glassy carbon electrode (GCE). The graphene oxide (GO) was fabricated using modified Hummers method and was electrochemically reduced on the surface of GCE by performing cyclic voltammograms from 0 to -1.5 V. The modification was optimized and properties of electrodes were determined using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The determination of Zn(II) was performed using differential pulse voltammetry technique, platinum wire as a counter electrode, and Ag/AgCl/3 M KCl reference electrode. Compared to the bare GCE the modified GCE/ERGO shows three times better electrocatalytic activity towards zinc ions, with an increase of reduction current along with a negative shift of reduction potential. Using GCE/ERGO detection limit 5 ng·mL-1 was obtained.

• Klíčová slova
• carbon, cyclic voltammetry, electrochemical impedance spectroscopy, electrochemistry, graphene oxide, heavy metal detection, reduced graphene oxide,
• Publikační typ
• časopisecké články MeSH

There is an arising and concerning issue in the field of bacterial resistance, which is confirmed by the number of deaths associated with drug-resistant bacterial infections. The aim of this study was to compare the effects of antibiotics on Staphylococcus aureus non-resistant strain and strains resistant to cadmium or lead ions. Metal resistant strains were created by the gradual addition of 2 mM solution of metal ions (cadmium or lead) to the S. aureus culture. An increasing antimicrobial effect of ampicillin, streptomycin, penicillin and tetracycline (0, 10, 25, 50, 75, 150, 225 and 300 µM) on the resistant strains was observed using a method of growth curves. A significant growth inhibition (compared to control) of cadmium resistant cells was observed in the presence of all the four different antibiotics. On the other hand, the addition of streptomycin and ampicillin did not inhibit the growth of lead resistant strain. Other antibiotics were still toxic to the bacterial cells. Significant differences in the morphology of cell walls were indicated by changes in the cell shape. Our data show that the presence of metal ions in the urban environment may contribute to the development of bacterial strain resistance to other substances including antibiotics, which would have an impact on public health.

• MeSH
• antibakteriální látky farmakologie   MeSH
• bakteriální léková rezistence * MeSH
• kadmium farmakologie   MeSH
• mikrobiální testy citlivosti MeSH
• olovo farmakologie   MeSH
• Staphylococcus aureus účinky léků   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antibakteriální látky MeSH
• kadmium MeSH
• olovo MeSH

Metallothioneins (MT) are low molecular weight, cysteine-rich proteins maintaining metal ions homeostasis. They play a role in carcinogenesis and may also cause chemoresistance. The aim of the study was to explore the importance of MT serum levels in children suffering from malignant tumours. This prospective study involves examination of 865 samples from 172 patients with malignant tumours treated from 2008 to 2011 at University Hospital Motol. MT serum levels were determined using differential pulse voltammetry-Brdicka reaction. Mean MT level was 2.7 ± 0.5 μM. There was no statistically significant difference between MT levels in different tumours. We also did not find any correlation between MT levels and response to therapy or clinical stages. However, we found a positive correlation between MT levels and age (p = 0.009) and a negative correlation with absolute lymphocyte number (p = 0.001). The fact that patients who had early disease recurrence had lower MT levels during the treatment (complete remission 2.67 vs. recurring 2.34, p = 0.001) seems to be important for clinical practice. Accordingly we believe that there is benefit in further studies of serum MT levels in tumours.

• MeSH
• dítě MeSH
• kojenec MeSH
• lidé MeSH
• metalothionein krev   MeSH
• mladiství MeSH
• nádorové biomarkery krev   MeSH
• nádory krev   farmakoterapie   MeSH
• předškolní dítě MeSH
• prognóza MeSH
• progrese nemoci MeSH
• Check Tag
• dítě MeSH
• kojenec MeSH
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• metalothionein MeSH
• nádorové biomarkery MeSH

Cadmium, as a hazardous pollutant commonly present in the living environment, represents an important risk to human health due to its undesirable effects (oxidative stress, changes in activities of many enzymes, interactions with biomolecules including DNA and RNA) and consequent potential risk, making its detection very important. New and unique technological and biotechnological approaches for solving this problems are intensely sought. In this study, we used the commonly occurring potential pathogenic microorganism Staphylococcus aureus for the determination of markers which could be used for sensing of cadmium(II) ions. We were focused on monitoring the effects of different cadmium(II) ion concentrations (0, 1.25, 2.5, 5, 10, 15, 25 and 50 μg mL(-1)) on the growth and energetic metabolism of Staphylococcus aureus. Highly significant changes have been detected in the metabolism of thiol compounds-specifically the protein metallothionein (0.79-26.82 mmol/mg of protein), the enzyme glutathione S-transferase (190-5,827 μmol/min/mg of protein), and sulfhydryl groups (9.6-274.3 μmol cysteine/mg of protein). The ratio of reduced and oxidized glutathione indicated marked oxidative stress. In addition, dramatic changes in urease activity, which is connected with resistance of bacteria, were determined. Further, the effects of cadmium(II) ions on the metabolic pathways of arginine, β-glucosidase, phosphatase, N-acetyl β-d-glucosamine, sucrose, trehalose, mannitol, maltose, lactose, fructose and total proteins were demonstrated. A metabolomic profile of Staphylococcus aureus under cadmium(II) ion treatment conditions was completed seeking data about the possibility of cadmium(II) ion accumulation in cells. The results demonstrate potential in the application of microorganisms as modern biosensor systems based on biological components.

• Klíčová slova
• Brdicka reaction, Staphylococcus aureus, biosensor, cadmium, electrochemistry, high performance liquid chromatography with electrochemical detection, metabolic activity, metabolome, microbiome, spectrophotometry, voltammetry,
• MeSH
• biosenzitivní techniky metody   MeSH
• disacharidy metabolismus   MeSH
• elektrochemické techniky MeSH
• fosfatasy metabolismus   MeSH
• glutathion metabolismus   MeSH
• glutathiondisulfid metabolismus   MeSH
• glutathiontransferasa metabolismus   MeSH
• hydrolasy metabolismus   MeSH
• kadmium analýza   metabolismus   farmakologie   MeSH
• látky znečišťující životní prostředí analýza   metabolismus   farmakologie   MeSH
• metabolismus účinky léků   MeSH
• metalothionein metabolismus   MeSH
• monosacharidy metabolismus   MeSH
• proliferace buněk účinky léků   MeSH
• proteiny metabolismus   MeSH
• Staphylococcus aureus cytologie   účinky léků   metabolismus   MeSH
• sulfhydrylové sloučeniny metabolismus   MeSH
• ureasa metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• arginine deiminase MeSH Prohlížeč
• disacharidy MeSH
• fosfatasy MeSH
• glutathion MeSH
• glutathiondisulfid MeSH
• glutathiontransferasa MeSH
• hydrolasy MeSH
• kadmium MeSH
• látky znečišťující životní prostředí MeSH
• metalothionein MeSH
• monosacharidy MeSH
• proteiny MeSH
• sulfhydrylové sloučeniny MeSH
• ureasa MeSH

The drugs based on platinum metals represent one of the oldest, but also one of the most effective groups of chemotherapeutic agents. Thanks to many clinical studies it is known that resistance of tumor cells to drugs is a frequent cause of chemotherapy failure. With regard to platinum based drugs, multidrug resistance can also be connected with increased expression of low-molecular weight protein metallothionein (MT). This study aimed at investigating the interactions of MT with cisplatin or carboplatin, using the adsorptive transfer technique coupled with differential pulse voltammetry Brdicka reaction (AdTS DPV Brdicka reaction), and a comparison of in vitro results with results obtained in vivo. The results obtained from the in vitro study show a strong affinity between platinum based drugs and MT. Further, we analyzed extracts of neuroblastoma cell lines treated with cisplatin or carboplatin. It is clear that neuroblastoma UKF-NB-4 cisplatin-resistant and cisplatin-sensitive cell lines unlikely respond to the presence of the platinum-based cytostatics cisplatin and carboplatin. Finally, we determined the level of MT in samples from rabbits treated with carboplatin and patients with retinoblastoma treated with the same drug.

• Klíčová slova
• anticancer therapy, metallothionein, platinum based anticancer drugs, resistance, retinoblastoma, tumor disease,
• MeSH
• antitumorózní látky * farmakokinetika   farmakologie   MeSH
• biologické modely MeSH
• cisplatina * farmakokinetika   farmakologie   MeSH
• karboplatina * farmakokinetika   farmakologie   MeSH
• králíci MeSH
• lidé MeSH
• metalothionein metabolismus   MeSH
• nádorové buněčné linie MeSH
• neuroblastom * farmakoterapie   metabolismus   patologie   MeSH
• retinoblastom * farmakoterapie   metabolismus   patologie   MeSH
• zvířata MeSH
• Check Tag
• králíci MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antitumorózní látky * MeSH
• cisplatina * MeSH
• karboplatina * MeSH
• metalothionein MeSH

BACKGROUND: Thiol-rich peptides and proteins possess a large number of biological activities and may serve as markers for numerous health problems including cancer. Metallothionein (MT), a small molecular mass protein rich in cysteine, may be considered as one of the promising tumour markers. The aim of this paper was to employ chronopotentiometric stripping analysis (CPSA) for highly sensitive detection of MT. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we used adsorptive transfer stripping technique coupled with CPSA for detection of cysteine, glutathione oxidized and reduced, phytochelatin, bovine serum albumin, and metallothionein. Under the optimal conditions, we were able to estimate detection limits down to tens of fg per ml. Further, this method was applied to detect metallothioneins in blood serum obtained from patients with breast cancer and in neuroblastoma cells resistant and sensitive to cisplatin in order to show the possible role of metallothioneins in carcinogenesis. It was found that MT level in blood serum was almost twice higher as compared to the level determined in healthy individuals. CONCLUSIONS/SIGNIFICANCE: This paper brings unique results on the application of ultra-sensitive electroanalytical method for metallothionein detection. The detection limit and other analytical parameters are the best among the parameters of other techniques. In spite of the fact that the paper is mainly focused on metallothionein, it is worth mentioning that successful detection of other biologically important molecules is possible by this method. Coupling of this method with simple isolation methods such as antibody-modified paramagnetic particles may be implemented to lab-on-chip instrument.

• MeSH
• buněčné linie MeSH
• elektrochemie metody   MeSH
• elektroforéza v polyakrylamidovém gelu MeSH
• králíci MeSH
• lidé MeSH
• metalothionein krev   moč   MeSH
• potenciometrie MeSH
• reprodukovatelnost výsledků MeSH
• zvířata MeSH
• Check Tag
• králíci MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• metalothionein MeSH

Due to anthropogenic activities, heavy metals still represent a threat for various trophic levels. If aquatic animals are exposed to heavy metals, we can obviously observe considerable toxicity. It is well known that organisms treated with heavy metals synthesize low molecular mass compounds rich in cysteine. In this work the effects of cadmium chloride (2.5, 5, 7.5, 10 and 12.5 mg/L) on common carp (Cyprinus carpio) was investigated. We determined cadmium content in tissue of muscle, liver and kidney by atomic absorption spectrometry with electrothermal atomization and content of metallothionein (MT) in the same tissues by the Brdicka reaction. Electrochemical methods can be considered as suitable and sensitive tools for MT determination in carp tissues. Results of our study showed a gradually enhancing of cadmium content in muscle with time and dose of cadmium chloride in water. MT levels in liver reached both high levels (above 130 ng/g) in fish exposed to 2.5, 5 and 7.5 mg/L and low level (to 50 ng/g) in fish exposed to 10 and 12.5 mg/L of cadmium chloride. This finding confirms that the synthesis of metallothioneins and binding capacity of these proteins is restricted.

• Klíčová slova
• Cyprinus carpio, bioaccumulation, heavy metals,
• Publikační typ
• časopisecké články MeSH

Mycotoxins are secondary metabolites produced by microfungi that are capable of causing disease and death in humans and other animals. This work was aimed at investigation of influence of mouldy wheat contaminated by pathogenic fungi producing mycotoxins on metallothionein levels in hepatic tissue of rats. The rats were administrating feed mixtures with different contents of vitamins or naturally mouldy wheat for 28 days. It was found that the wheat contained deoxynivalenol (80 +/- 5 microg per kg of mouldy wheat), zearalenone (56 +/- 3 microg/kg), T2-toxin (20 +/- 2 microg/kg) and aflatoxins as a sum of B1, B2, G1 and G2 (3.9 +/- 0.2 microg/kg). Rats were fed diets containing 0, 33, 66 and 100% naturally moulded wheat. Control group 0, 33, 66 and 100% contained vitamins according to Nutrient Requirements of Rats (NRC). Other four groups (control group with vitamins, vit33, vit66 and vit100%) were fed on the same levels of mouldy wheat, also vitamins at levels 100% higher than the previous mixtures. We determined weight, feed conversion and performed dissection to observe pathological processes. Changes between control group and experimental groups exposed to influence of mouldy wheat and experimental groups supplemented by higher concentration of vitamins and mouldy wheat were not observed. Livers were sampled and did not demonstrate significant changes in morphology compared to control either. In the following experiments the levels of metallothionein as a marker of oxidative stress was determined. We observed a quite surprising trend in metallothionein levels in animals supplemented with increased concentration of vitamins. Its level enhanced with increasing content of mouldy wheat. It was possible to determine a statistically significant decline (p<0.05) between control group and groups of animals fed with 33, 66 and 100% mouldy wheat. It is likely that some mycotoxins presented in mouldy wheat are able to block the mechanism of metallothionein synthesis.

• Klíčová slova
• Brdicka reaction, Differential pulse voltammetry, Fungi, Liver metabolism, Metallothionein, Mycotoxins, Rats, Vitamins,
• MeSH
• aflatoxiny chemie   toxicita   MeSH
• houby izolace a purifikace   metabolismus   MeSH
• játra účinky léků   metabolismus   patologie   MeSH
• krysa rodu Rattus MeSH
• metalothionein metabolismus   MeSH
• oxidační stres účinky léků   MeSH
• potkani Wistar MeSH
• pšenice mikrobiologie   MeSH
• T-2 toxin chemie   toxicita   MeSH
• tělesná hmotnost účinky léků   MeSH
• trichotheceny chemie   toxicita   MeSH
• vitaminy farmakologie   MeSH
• zearalenon chemie   toxicita   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• aflatoxiny MeSH
• deoxynivalenol MeSH Prohlížeč
• metalothionein MeSH
• T-2 toxin MeSH
• trichotheceny MeSH
• vitaminy MeSH
• zearalenon MeSH

Treatment strategies for tumour diseases are progressively focusing on personalization of medicine. However, this focus requires methods revealing the early general biological mechanisms, including the formation anti-cancer drugs' resistance. The low molecular mass protein metallothionein is thought to be the crucial for the formation of resistance in tumour treatment based on the platinum-cytostatics. The interactions between metallothionein (MT) and cisplatin were determined by the adsorptive transfer stripping technique coupled with the differential pulse votlammetry Brdickás reaction. The signals related to the MT-cisplatin complex appeared at -0.9 V. The formation of this complex depended on the time of interaction between cisplatin and MT. The complex formation was consequently confirmed by quartz crystal microbalance analyses. The formation of this complex was detectable even after a 20 s long interaction. Moreover, we detected presence of MT-cisplatin complex in the blood of male rats treated with this drug.

• Klíčová slova
• Brdickás reaction, Cancer, Cisplatin, Metallothionein, Protein-Drug Interaction, Quartz Crystal Microbalance, Voltammetry,
• Publikační typ
• časopisecké články MeSH