|
|
Accumulation and biotransformation of nitramines in plant tissue
Šídlová, Petra ; Skálová, Lenka (advisor) ; Szotáková, Barbora (referee)
Explosives are toxic, recalcitrant to degradation and contaminate large areas of land and ground water. Remediation of these xenobiotics is difficult and an enormous logistical task. Phytoremediation is a technique that offers an environment friendly, low-cost alternative to current remediation techniques. However this approach is hindered by the low metabolic abilities of plants towards these xenobiotic compounds and the phytotoxicity of these compounds. The fate of the explosives RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) and HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) on exposure to plant was investigated in hydroponic system of sunflower (Heliantus annuus L.) and hemp (Cannabis sativa L.) approximately for more than 10 days. Exposure levels were: 10mg/l and 50mg/l RDX, respectively HMX for sunflower; 25mg/l and 50mg/l RDX , 5mg/l and 50mg/l HMX for hemp. Their ecotoxicites were characterized by the test based on the inhibition of elongation of primary roots 3days-old mustard and hemp seedlings. Extracts of plants were analyzed by HPLC (liquid chromatography). These study showed that RDX and HMX was taken up by both plant species. The accumulation of these nitramines was observed more in the roots than in the aerial parts of the plants, except for RDX in hemp, where the...
|
|
|
The assay of peroxidases activities and their comparison in various helminths
Sulanová, Lenka ; Skálová, Lenka (advisor) ; Szotáková, Barbora (referee)
Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Biochemical Sciences Candidate: Lenka Sulanová Supervisor: Doc. RNDr. Lenka Skálová, Ph.D. Title of diploma thesis: The assay of peroxidases activities and their comparison in various helminths The aim of diploma thesis was to search for simple methods for determination of peroxidases activities, to choose a suitable method, optimize it and compare it with the method used in the workplace. The 3,3′,5,5′-tetramethylbenzidine (TMB) has been used as a substrate in selected technique. I have optimized this method and compared it with the formely applied method using substrate O-phenylenediamine dihydrochloride (OPD). Method working with TMB is more precise, more comfortable but more expensive than method using OPD. I have applied both of methods for assay of peroxidases activities in the subcellular fractions of the two species of helminths: Dicrocoelicum dendriticum and Haemonchus contortus. I found out that activities of peroxidases are higher at Haemonchus contortus than at Dicrocoelicum dendriticum. Different activities of peroxidases were observed in the subcellular fractions of the Haemonchus contortus strains sensitive and resistant to anthelmintics. The ex vivo contact of Dicrocoelicum dendriticum with...
|
|
| |
|
|
Aspects of Gene Regulation of CYP3A4 in Hepatic Tissue.
Krausová, Lucie ; Štaud, František (advisor) ; Mičuda, Stanislav (referee) ; Skálová, Lenka (referee)
1 Summary CYP3A4 is an important enzyme involved in elimination of majority of metabolized xenobiotics. It plays a major role in the detoxification system of the human body, therefore it is responsible for many drug-drug interactions (DDIs). DDI present a complication of current pharmacotherapy, in the extreme they can lead in failure of therapy or in life-threatening toxic effects. DDIs are caused by changes in enzymatic activity of CYP3A4, which is highly variable among individuals. An important mechanism of modulating CAP3A4 activity is the regulation of inducible transcription by nuclear receptors, especially PXR, CAR and GR. The structure of CYP3A4 promoter and mechanisms of transcriptional regulation has been studding intensively for many years, but the research of relationship of nuclear receptors and transcriptional cofactors in CYP3A4 transactivation is still incomplete. Present work contributes to elucidation of some questions concerning the effects of azole antimycotics on CYP3A4 transcription via PXR, potency of valproic acid to activate PXR and CAR or determinants of CYP3A4 expression via GR in placental cells. The experiments were performed with up-to-date molecular biology methods and using in vitromodels of the primary human hepatocytes and hepatoma cell lines. To the aims of the doctoral...
|
|
|
Factors Affecting Metabolism of Anthelmintics
Forstová, Veronika ; Skálová, Lenka (advisor) ; Machala, Miroslav (referee) ; Chládek, Jaroslav (referee)
Nowadays, anthelmintic therapy is the main method in the fight with parasitic worms. Anthelmintics, as well as other xenobiotics, undergo structural changes by effect of biotransformation enzymes, when lipophilic substances are transformed to polar substances more easily eliminable from the organism. Generally, biological effects of metabolites and parent compound are different. Activity of biotransformation enzymes is thus the fundamental factor influencing velocity of detoxification and elimination of the compound from the body and duration of drug effect as well. Modulation of biotransformation enzymes' activities can lead to changes in pharmacokinetic parameters of drug itself as well as other xenobiotics and thus to the risk of decrease in desired effect and/or increase in adverse effects with corresponding impact on the quality of drug therapy. In addition, possible risk of drug residues' presence in animal products has to be considered in farm animals. Biotransformation of xenobiotics is affected by many physiological as well as pathological factors. These factors can be divided into inter-individual (species, gender, genetic polymorphism) and intra-individual (age, diet, medication, disease, etc.). All these factors cause wide variability in occurrence and activity of biotransformation...
|
|
| |
|
| |
|
| |
|
| |
|
| |
guest ::
RSS feed.