The fungus Monascus is a well-known source of secondary metabolites with interesting pharmaceutical and nutraceutical applications. In particular, Monascus pigments possess a wide range of biological activities (e.g. antimicrobial, antioxidant, anti-inflammatory or antitumoral). To broaden the scope of their possible application, this study focused on testing Monascus pigment extracts as potential photosensitizing agents efficient in antimicrobial photodynamic therapy (aPDT) against bacteria. For this purpose, eight different extracts of secondary metabolites from the liquid- and solid-state fermentation of Monascus purpureus DBM 4360 and Monascus sp. DBM 4361 were tested against Gram-positive and Gram-negative model bacteria, Bacillus subtilis and Escherichia coli and further screened for ESKAPE pathogens, Staphylococcus aureus and Pseudomonas aeruginosa. To the bacterial culture, increasing concentration of extracts was added and it was found that all extracts showed varying antimicrobial activity against Gram-positive bacteria in dark, which was further increased after irradiation. Gram-negative bacteria were tolerant to the extracts' exposure in the dark but sensitivity to almost all extracts that occurred after irradiation. The Monascus sp. DBM 4361 extracts seemed to be the best potential candidate for aPDT against Gram-positive bacteria, being efficient at low doses, i.e. the lowest total concentration of Monascus pigments exhibiting aPDT effect was 3.92 ± 1.36 mg/L for E. coli. Our results indicate that Monascus spp., forming monascuspiloin as the major yellow pigment and not-forming mycotoxin citrinin, is a promising source of antimicrobials and photoantimicrobials.

• MeSH
• antibakteriální látky * farmakologie   chemie   MeSH
• biologické pigmenty farmakologie   MeSH
• biologické přípravky farmakologie   chemie   MeSH
• fotochemoterapie MeSH
• fotosenzibilizující látky farmakologie   chemie   MeSH
• grampozitivní bakterie účinky léků   účinky záření   MeSH
• komplexní směsi farmakologie   chemie   MeSH
• mikrobiální testy citlivosti * MeSH
• Monascus * chemie   metabolismus   MeSH
• mycelium * chemie   účinky záření   účinky léků   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• red yeast rice MeSH Prohlížeč

The complexes of Fe(II), Mn(II) and Ni(II) with a combination of a Schiff base, nitrogen-donor ligand or macrocyclic ligand and trithiocyanuric acid (ttcH3) were prepared and characterized by elemental analysis and spectroscopies. Crystal and molecular structures of the iron complex of composition [Fe(L1)](ttcH2)(ClO4)·EtOH·H2O (1), where L1 is Schiff base derived from tris(2-aminoethyl)amine and 2-pyridinecarboxaldehyde, were solved. It was found that the Schiff base is coordinated to the central iron atom by six nitrogens forming deformed octahedral arrangement, whereas trithiocyanurate(1-) anion, perchlorate and solvent molecules are not coordinated. The X-ray structure of the Schiff base sodium salt is also presented and compared with the iron complex. The anticholinesterase activity of the complexes was also studied.

• MeSH
• cholinesterasové inhibitory chemická syntéza   chemie   farmakologie   MeSH
• cholinesterasy metabolismus   MeSH
• enzymatické testy MeSH
• ethylendiaminy chemie   MeSH
• komplexní sloučeniny chemická syntéza   chemie   farmakologie   MeSH
• komplexní směsi chemie   MeSH
• krysa rodu Rattus MeSH
• krystalografie rentgenová MeSH
• ligandy MeSH
• mangan chemie   MeSH
• mozek účinky léků   enzymologie   MeSH
• nikl chemie   MeSH
• pyridiny chemie   MeSH
• Schiffovy báze chemie   MeSH
• triaziny chemie   MeSH
• železo chemie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• cholinesterasové inhibitory MeSH
• cholinesterasy MeSH
• ethylendiaminy MeSH
• komplexní sloučeniny MeSH
• komplexní směsi MeSH
• ligandy MeSH
• mangan MeSH
• nikl MeSH
• picolinaldehyde MeSH Prohlížeč
• pyridiny MeSH
• Schiffovy báze MeSH
• triaziny MeSH
• tris(2-aminoethyl)amine MeSH Prohlížeč
• trithiocyanuric acid MeSH Prohlížeč
• železo MeSH

Residues of steroid hormones have become a cause for concern because they can affect the biological activity of non-target organisms. Steroid hormones are a potential risk for wildlife and humans through the consumption of contaminated food or water. Their determination requires extraction and clean-up steps, prior to detection, to reach low concentration levels. In recent years, a great effort has been made to develop new analytical methodologies, such as microextraction techniques, that reduce environmental pollution. Researchers have modified old methods to incorporate procedures that use less-hazardous chemicals or that use smaller amounts of them. They are able to do direct analysis using miniaturised equipment and reduced amounts of solvents and wastes. These accomplishments are the main objectives of green analytical chemistry. In this overview, we focus on microextraction techniques for the determination of steroid hormones in biological (e.g., human urine, human serum, fish, shrimp and prawn tissue and milk) and environmental (e.g., wastewaters, surface waters, tap waters, river waters, sewage sludges, marine sediments and river sediments) samples. We comment on the most recent applications in sorptive-microextraction modes, such as solid phase microextraction (SPME) with molecularly imprinted polymers (MIPs), in-tube solid-phase microextraction (IT-SPME), stir-bar sorptive extraction (SBSE) and microextraction in packed sorbent (MEPS). We also describe liquid-phase microextraction (LPME) approaches reported in the literature that are applied to the determination of steroid hormones.

• MeSH
• adsorpce MeSH
• chemické látky znečišťující vodu analýza   MeSH
• hormony analýza   chemie   MeSH
• komplexní směsi analýza   chemie   MeSH
• lidé MeSH
• mikroextrakce na pevné fázi přístrojové vybavení   metody   MeSH
• molekulový imprinting metody   MeSH
• monitorování životního prostředí přístrojové vybavení   metody   MeSH
• odpadní vody analýza   chemie   MeSH
• plynová chromatografie s hmotnostně spektrometrickou detekcí metody   MeSH
• rozpouštědla chemie   MeSH
• steroidy analýza   chemie   MeSH
• technologie zelené chemie přístrojové vybavení   metody   MeSH
• tělesné tekutiny chemie   MeSH
• znečištění životního prostředí prevence a kontrola   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• chemické látky znečišťující vodu MeSH
• hormony MeSH
• komplexní směsi MeSH
• odpadní vody MeSH
• rozpouštědla MeSH
• steroidy MeSH

Toxicity and liver tumor promotion of cyanotoxins microcystins have been extensively studied. However, recent studies document that other metabolites present in the complex cyanobacterial water blooms may also have adverse health effects. In this study we used rat liver epithelial stem-like cells (WB-F344) to examine the effects of cyanobacterial extracts on two established markers of tumor promotion, inhibition of gap-junctional intercellular communication (GJIC) and activation of mitogen-activated protein kinases (MAPKs) - ERK1/2. Extracts of cyanobacteria (laboratory cultures of Microcystis aeruginosa and Aphanizomenon flos-aquae and water blooms dominated by these species) inhibited GJIC and activated MAPKs in a dose-dependent manner (effective concentrations ranging 0.5-5mgd.w./mL). Effects were independent of the microcystin content and the strongest responses were elicited by the extracts of Aphanizomenon sp. Neither pure microcystin-LR nor cylindrospermopsin inhibited GJIC or activated MAPKs. Modulations of GJIC and MAPKs appeared to be specific to cyanobacterial extracts since extracts from green alga Chlamydomonas reinhardtii, heterotrophic bacterium Klebsiella terrigena, and isolated bacterial lipopolysaccharides had no comparable effects. Our study provides the first evidence on the existence of unknown cyanobacterial toxic metabolites that affect in vitro biomarkers of tumor promotion, i.e. inhibition of GJIC and activation of MAPKs.

• MeSH
• aktivace enzymů účinky léků   MeSH
• alkaloidy MeSH
• Aphanizomenon chemie   izolace a purifikace   MeSH
• bakteriální toxiny MeSH
• buněčné linie MeSH
• časové faktory MeSH
• extracelulárním signálem regulované MAP kinasy metabolismus   MeSH
• fosforylace účinky léků   MeSH
• karcinogeny chemie   toxicita   MeSH
• komplexní směsi chemie   toxicita   MeSH
• krysa rodu Rattus MeSH
• mezerový spoj účinky léků   MeSH
• mezibuněčná komunikace účinky léků   MeSH
• Microcystis chemie   izolace a purifikace   MeSH
• mikrocystiny analýza   toxicita   MeSH
• mitogenem aktivované proteinkinasy metabolismus   MeSH
• sinice chemie   izolace a purifikace   MeSH
• sladká voda mikrobiologie   MeSH
• toxiny kmene Cyanobacteria MeSH
• uracil analogy a deriváty   toxicita   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• srovnávací studie MeSH
• Geografické názvy
• Česká republika MeSH
• Názvy látek
• alkaloidy MeSH
• bakteriální toxiny MeSH
• cylindrospermopsin MeSH Prohlížeč
• extracelulárním signálem regulované MAP kinasy MeSH
• karcinogeny MeSH
• komplexní směsi MeSH
• mikrocystiny MeSH
• mitogenem aktivované proteinkinasy MeSH
• toxiny kmene Cyanobacteria MeSH
• uracil MeSH

A method of numerical calculation of the fourth virial coefficients of the mixture of additive hard spheres is proposed. The results are compared with an exact analytical formula for the fourth partial virial coefficient B4[1] (i.e., three spheres of diameters sigma1 and one sphere of diameter sigma2) and a semiempirical expression for B4[2] (i.e., two spheres of each kind). It is shown that the first formula is nonanalytic and the implication to the equations of state for hard-sphere mixtures is discussed.

• MeSH
• algoritmy * MeSH
• chemické modely * MeSH
• komplexní směsi chemie   MeSH
• počítačová simulace MeSH
• reologie metody   MeSH
• roztoky chemie   MeSH
• statistické modely * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• komplexní směsi MeSH
• roztoky MeSH

Sorption is an important process for the transport of radionuclides through backfill materials in a radioactive waste underground repository. Within this study, sorption of Cs on selected Czech clay materials and their mixtures with sand was investigated by batch tests. The experiments were performed under oxic conditions at 25 degrees C. Synthetic groundwater as a liquid phase and unconditioned clays (as they were provided by their producer) were used to reach the natural conditions as close as possible. Distribution ratios (Rds) of Cs for all selected clays rise with increase of the clay fraction in clay/sand mixtures in agreement with previous works studying sorption behaviour of such mixtures. The rise of Rds is from 10(2) cm3 g(-1) for mixtures with 80% of sand to 10(3) cm3 g(-1) for pure clays. There are significant differences between natural and technologically modified clays.

• MeSH
• adsorpce MeSH
• difuze MeSH
• jíl MeSH
• komplexní směsi analýza   chemie   MeSH
• monitorování životního prostředí metody   MeSH
• oxid křemičitý analýza   chemie   MeSH
• radioaktivní látky znečišťující půdu analýza   MeSH
• radioizotopy cesia analýza   chemie   MeSH
• radiometrie metody   MeSH
• silikáty hliníku analýza   chemie   MeSH
• silikáty chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Geografické názvy
• Česká republika MeSH
• Názvy látek
• jíl MeSH
• komplexní směsi MeSH
• oxid křemičitý MeSH
• radioaktivní látky znečišťující půdu MeSH
• radioizotopy cesia MeSH
• silikáty hliníku MeSH
• silikáty MeSH
• Smectite MeSH Prohlížeč

Azidothymidine (AZT, 3'-azido-3'-deoxythymidine, Zidovudine, Retrovir) is an approved and widely used antiretroviral drug for the treatment of human immunodeficiency virus (HIV) infection. Dynamic electrochemical methods have been employed for the fast and inexpensive determination of this drug in natural samples. The electrochemical signal of AZT, resulting from the reduction of azido group, was studied by square wave voltammetry (SWV), linear sweep voltammetry (LSV) and elimination voltammetry with linear scan (EVLS) using a hanging mercury drop electrode (HMDE). This paper explores the possibility of determining AZT in the presence of native (dsDNA) or denatured calf thymus DNA (ssDNA), and/or some synthetic oligodeoxynucleotides (ODNs). The detection limit of AZT in the absence and in the presence of ssDNA (10 microg/ml) is 1 and 250 nM, respectively. It was found that the signal of AZT is not substantially affected by the presence of DNA. We can therefore assume that the electrons are transferred through the adsorption layer of nucleic acids. By using the elimination procedure, both irreversible reduction signals of AZT and DNA are augmented. Moreover, the elimination signal in the peak-counterpeak form may indicate the adsorption of the analytes on the electrode surface preceding an electron transfer.

• MeSH
• chromozomy chemie   MeSH
• DNA analýza   chemie   MeSH
• elektrochemie metody   MeSH
• komplexní směsi analýza   chemie   MeSH
• oligonukleotidy analýza   chemie   MeSH
• senzitivita a specificita MeSH
• zidovudin analýza   chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• validační studie MeSH
• Názvy látek
• calf thymus DNA MeSH Prohlížeč
• DNA MeSH
• komplexní směsi MeSH
• oligonukleotidy MeSH
• zidovudin MeSH