Supercritical fluid extraction of steroids from biological samples and first experience with solid-phase microextraction-liquid chromatography

Modern extraction techniques, supercritical fluid extraction (SFE) and solid-phase microextraction (SPME) were used for isolation of four corticosteroids from biological matrices. SFE was applied for extraction from solid matrices--hydromatrix and pig muscle. The effects of various extraction conditions were studied. Good recoveries of corticosteroids from hydromatrix were obtained under moderate extraction conditions and without modification of carbon dioxide. On the contrary, the best recoveries from spiked pig muscle were obtained with modified carbon dioxide. SPME was used for extraction from liquid samples--water and urine. The eventuality of the use of this fast solvent-free technique in steroid analysis is demonstrated. Several extraction conditions were optimized. Extracted steroids were analyzed by HPLC-UV and a special SPME-HPLC interface was used for combination with SPME.     

Smallanthus sonchifolius and Lepidium meyenii - prospective Andean crops for the prevention of chronic diseases

Smallanthus sonchifolius (yacon) and Lepidium meyenii (maca) were the traditional crops of the original population of Peru where they are also still used in folk medicine. These plants are little known in Europe and Northern America although at least yacon can be cultivated in the climatic conditions of these regions. This article deals with the botany and the composition, the structure of main constituents, biological activity of these plants and the cultivation of yacon in the Czech Republic. The potential of yacon tubers to treat hyperglycemia, kidney problems and for skin rejuvenation and the antihyperglycemic and cytoprotective activity of its leaves seems to be related mostly to its oligofructan and phenolic content, respectively. Maca alkaloids, steroids, glucosinolates, isothicyanates and macamides are probably responsible for its aptitude to act as a fertility enhancer, aphrodisiac, adaptogen, immunostimulant, anabolic and to influence hormonal balance. Yacon and maca are already on the European market as prospective functional foods and dietary supplements, mainly for use in certain risk groups of the population, e.g. seniors, diabetics, postmenopausal women etc.     

Two approaches to biological decontamination of groundwater and soil polluted by aromatics-characterization of microbial populations.

As part of the EU project MULTIBARRIERS, six new endogenous aerobic bacterial isolates able to grow in the presence of BTmX (benzene, toluene, m-xylene) were characterized with respect to their growth specificities. Preliminary analysis included restriction fragment length polymorphism profiles and 16S rDNA sequencing. The diversity of these strains was confirmed by denaturing gradient gel electrophoresis. Additional aerobic bacterial strains were isolated from the rhizospheres of plants grown in polychlorinated biphenyl (PCB)-contaminated soils. Pot experiments were designed to show the beneficial effect of plants on the bacterial degradation of PCBs. The effect of PCB removal from soil was evaluated and bacteria isolated from three different plant species were examined for the presence of the bph operon.     

Differential effect of phosphatidylethanolamine depletion on raft proteins: further evidence for diversity of rafts in Saccharomyces cerevisiae

A considerable amount of evidence supports the idea that lipid rafts are involved in many cellular processes, including protein sorting and trafficking. We show that, in this process, also a non-raft lipid, phosphatidylethanolamine (PE), has an indispensable function. The depletion of this phospholipid results in an accumulation of a typical raft-resident, the arginine transporter Can1p, in the membranes of Golgi, while the trafficking of another plasma membrane transporter, Pma1p, is interrupted at the level of the ER. Both these transporters associate with a Triton (TX-100) resistant membrane fraction before their intracellular transport is arrested in the respective organelles. The Can1p undelivered to the plasma membrane is fully active when reconstituted to a PE-containing vesicle system in vitro. We further demonstrate that, in addition to the TX-100 resistance at 4 degrees C, Can1p and Pma1pa exhibit different accessibility to nonyl glucoside (NG), which points to distinct intimate lipid surroundings of these two proteins. Also, at 20 degrees C, these two proteins are extracted by TX-100 differentially. The features above suggest that Pma1p and Can1p are associated with different compartments. This is independently supported by the observations made by confocal microscopy. In addition we show that PE is involved in the stability of Can1p-raft association.     

Estrogens influence behavioral responses in a kainic acid model of neurotoxicity

The behavioral and neuroprotective effects of 17beta-estradiol (E2), on ovariectomized rats treated with a subconvulsive dose (7 mg/kg bw, ip) of kainic acid (KA), were examined. Estradiol was administered either acutely (150 mug/rat, ip) along with KA, 14 days post-ovariectomy, or chronically (sc capsules providing proestrus estrogen levels in serum) starting at ovariectomy. Exploratory behavior, as deduced by sniffing in the open field test, was reduced in KA-treated rats. Both hormonal schemes partially restored sniffing behavior in KA-lesioned subjects. Moreover, acute and chronic E2 administration in KA-treated rats resulted in increased vertical and horizontal activity of these animals in the open field test. Memory for object recognition was reduced following KA and was not restored by hormonal treatments. Acute, but not chronic, E2 coadministration with KA significantly impaired spatial performance in the water maze task, while KA alone had no effect. Both acute and chronic estradiol administration rescued hilar and CA1 neurons from KA-induced cell death. Chronic, but not acute, E2 increased neurofilament immunoreactivity in the mossy fibers of the dentate gyrus neurons, similarly to KA. Our results show that although estradiol administration in KA-treated rats has beneficial effects on cell survival, it has diverse effects on exploratory behavior, object, and spatial memory. Estradiol effects on KA-lesioned animals depended on the duration and timing of exposure to the hormone, implying different mechanisms of hormone actions.     

Non-enzymatic posttranslational modifications of bovine serum albumin by oxo-compounds investigated by chromatographic and electrophoretic methods

Non-enzymatic posttranslational modifications of bovine serum albumin (BSA) by oxo-compounds, particularly glucose, ribose, glyoxal and glutardialdehyde, have been investigated using a set of modern chromatographic and electrophoretic separation methods. High-performance liquid chromatography (HPLC) alternatively with UV spectrophotometric (diode array) or mass spectrometric (MS) detection, polyacrylamide gel electrophoresis (PAGE) with Coomassie brilliant blue staining detection, and capillary zone electrophoresis (CZE) with UV spectrophotometric detection have been employed for the investigation of the chemical and structural changes of BSA caused by its reaction with the above oxo-compounds exhibiting different degree of reactivity. The extent of modifications was found to be dependent on the nature of the oxo-compound used and progressed in the glucose相似文献   

Medfly promoters relevant to the sterile insect technique

This review summarizes structural and functional studies on medfly promoters and regulatory elements that can be used for driving sex-specific, conditional and constitutive gene expression in this species. Sex-specific and conditional promoters are important for generating transgenic sexing strains that could increase the performance of the Sterile Insect Technique while strong constitutive promoters are necessary for developing sensitive transgenic marker systems. The review focuses on the functional analysis of the promoters of two male-specific and heat shock medfly genes. A special emphasis is put on the potential utility of these promoters for developing transgenic sexing strains.