Antioxidant and detoxifying enzymes in the liver and kidney of pheasants after intoxication by herbicides MCPA and ANITEN

The activity of antioxidant and detoxifying enzymes, such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSHPx), glutathione reductase, glutathione-S-transferase (GST), the contents of thiobarbituric acid reactive substances, and the superoxide dismutase and glutathione-S-transferase isoenzyme patterns, were determined in the liver and kidney of pheasants after acute intoxication by herbicides MCPA and ANITEN I. In the liver, the activity of antioxidant enzymes was significantly decreased in the group given ANITEN I. New superoxide dismutase isoforms (pI 6.30, 6.85, 7.00) and higher intensity of isoform with pI 6.60 were observed after isoelectrofocusing in all experimental groups. In the kidney, the activity of superoxide dismutase was significantly decreased, and a higher intensity of superoxide dismutase isoforms (pI 6.00 and 6.60) was observed in all experimental groups. The contents of thiobarbituric acid reactive substances were significantly increased in the group with ANITEN I. The glutathione-S-transferase isoenzyme pattern was studied by using subunit-specific substrates and by Western blotting. The activity of glutathione-S-transferase with ethacrynic acid and cross-reactivity with rat subunit 7 was lower in all experimental groups in the kidney and liver, except in the liver of the group given a higher dose of ANITEN I. In this group, we have found a 2.10-fold higher activity to ethacrynic acid and a strong induction of subunit 7. © 1998 John Wiley & Sons, Inc. J Biochem Toxicol 12: 235–244, 1998     

Changes in Conformation,Stability and Condensation of DNA by Univalent and Divalent Cations in Methanol-Water Mixtures

Abstract

Circular dichroism spectroscopy, absorption spectroscopy, measurements of T_m values, sedimentation analysis and electron microscopy were used to study properties of calf thymus DNA in methanol-water mixtures as a function of monovalent cation (Na⁺ or Cs⁺) concentration and also in the presence of divalent cations Ca²⁺, Mg²⁺, and Mn²⁺. In the absence of divalent cations only slight conformational changes occured and no condensation and/or aggregation could be detected. The T_m values depend on the amount of methanol and on the nature and concentration of cations. In methanol-water mixtures higher thermal stability was observed in solutions containing Cs⁺ ions. Up to 40% (v/v) methanol the addition of divalent ions leads to DNA stabilization. At methanol concentration higher than 50% the presence of divalent cations causes DNA condensation and denaturation even at room temperature. The denaturation is reversible with respect to EDTA addition indicating that no separation of complementary strands occured and the resulting form of DNA is probably similar to the P form. DNA destacking appears to be a direct consequence of stronger cation binding by the condensed DNA in methanol-water mixtures.     

Necrosis ofAesculus hippocastanum L.

V práci trvající t?i léta byla sledována choroba jírovce madalu (Aesculus hippocastanum L.), u nás i jinde v st?ední Evropě v?eobecně roz?í?ená. Hlavním pracovi?těm byl zámecký park v Lu?anech u P?e?tic (Hlávkova nadace). P?íznaky a jejich vývoj byly pozorovány také na mnohých jiných místech. Podle t?ídění L. Bose (Wageningen) pat?í tyto symptomy do skupin barevné změny (II), Nekrosa (IV), Deformace (VII) a ?áste?ně i Redukce r?stu (plod?). Jde o chorobu, kterou p?ed 60 lety popisovalSorauer aThomas jako abiosu. Poněvad? některé zjevy poukazovaly na chorobu virového p?vodu, byly podniknuty diagnostické zkou?ky. Serologická byla negativní pro chemismus madalových list?, které nejsou vhodným materiálem pro tuto metodu. Zkou?ky roubovací a o?kovací na zdravých semená?ích byly positivní. Virová nekrosa madal? je choroba systémová, která není p?ená?ena mechanicky dotekem. Snadno se v?ak p?ená?í roubováním a o?kováním. Některé známky nasvěd?ují té? pravděpodobnosti, ?e do jisté míry m??e být p?ená?ena i semenem.     

Index of names of syntaxa typified in 1988

Following the “Index of new names” (Theurillat etMoravec 1990a), the present work collects the syntaxa (in the sense of the Code of Phytosociological Nomenclature,Barkman et al. 1986) above subassociation rank typified in 1988. The list comprises 27 syntaxa.     

Zinc has ambiguous effects on chromium (VI)-induced oxidative stress and apoptosis

Zinc is an important cellular antioxidant. We investigated its role in chromium-induced oxidative stress and apoptosis in human tumor cell line Hep-2. The measured parameters included intracellular labile zinc content (Zinquin-E fluorescence), cell viability (WST-1 assay), oxidative stress (spectrophotometry), mitochondrial potential (flow cytometry), caspase-3 activity, and PARP cleavage (immunofluorescence). We found that Hep-2 cells contain abundant labile zinc stores that may be depleted by the ionophore TPEN or increased by external zinc supplementation. Chromium (VI)-induced cytotoxicity and apoptosis were enhanced in zinc-depleted cells after 24 h, in particular at chromium (VI) concentrations of 50 and 150 micromol/l. On the other hand, elevated levels of labile zinc were able to protect against apoptosis induced by 10 micromol/l chromium (VI) but at higher chromium (VI) concentrations (50 and 150 micromol/l) acted synergistically, significantly enhancing oxidative stress and the course of apoptosis, possibly through oxidative stress and mitochondrial damage.     

Protective effects of dexrazoxane against acute ischaemia/reperfusion injury of rat hearts

Dexrazoxane (DEX), an inhibitor of topoisomerase II and intracellular iron chelator, is believed to reduce the formation of reactive oxygen species (ROS) and protects the heart from the toxicity of anthracycline antineoplastics. As ROS also play a role in the pathogenesis of cardiac ischaemia/reperfusion (I/R) injury, the aim was to find out whether DEX can improve cardiac ischaemic tolerance. DEX in a dose of 50, 150, or 450?mg·(kg body mass)(-1) was administered intravenously to rats 60?min before ischaemia. Myocardial infarct size and ventricular arrhythmias were assessed in anaesthetized open-chest animals subjected to 20?min coronary artery occlusion and 3?h reperfusion. Arrhythmias induced by I/R were also assessed in isolated perfused hearts. Only the highest dose of DEX significantly reduced infarct size from 53.9%?± 4.7% of the area at risk in controls to 37.5%?± 4.3% without affecting the myocardial markers of oxidative stress. On the other hand, the significant protective effect against reperfusion arrhythmias occurred only in perfused hearts with the dose of DEX of 150?mg·kg(-1), which also tended to limit the incidence of ischaemic arrhythmias. It is concluded that DEX in a narrow dose range can suppress arrhythmias in isolated hearts subjected to I/R, while a higher dose is needed to limit myocardial infarct size in open-chest rats.     

Washing technique for monitoring mites in apple orchards

A shake-and-wash technique for monitoring the predatory phytoseiid mitesTyphlodromus pyri, Amblyseius finlandicus, and their prey,Panonychus ulmi, Tetranychus urticae andAculus schlechtendali in commercial apple orchards was developed. The removal and recovery of mites from leaves, shoots and spurs is based on agitating the plant material by hand in alcohol and subsequently removing the mites using a separating funnel. The mites are quickly killed and easily washed off the plant material, and are thus well preserved for further study. The technique is more efficient than directly counting the mites on plant material under a dissection microscope and can be easily employed both in the laboratory and in the field.     

Systems biology of persistent infection: tuberculosis as a case study

The human immune response does an excellent job of clearing most of the pathogens that we encounter throughout our lives. However, some pathogens persist for the lifetime of the host. Despite many years of research, scientists have yet to determine the basis of persistence of most pathogens, and have therefore struggled to develop reliable prevention and treatment strategies. Systems biology provides a new and integrative tool that will help to achieve these goals. In this article, we use Mycobacterium tuberculosis as an example of how systems-biology approaches have begun to make strides in uncovering important facets of the host-pathogen interaction.     

Soft Tissue Artefacts of the Human Back: Comparison of the Sagittal Curvature of the Spine Measured Using Skin Markers and an Open Upright MRI

Soft tissue artefact affects the determination of skeletal kinematics. Thus, it is important to know the accuracy and limitations of kinematic parameters determined and modelled based on skin marker data. Here, the curvature angles, as well as the rotations of the lumbar and thoracic segments, of seven healthy subjects were determined in the sagittal plane using a skin marker set and compared to measurements taken in an open upright MRI scanner in order to understand the influence of soft tissue artefact at the back. The mean STA in the flexed compared to the extended positions were 10.2±6.1 mm (lumbar)/9.3±4.2 mm (thoracic) and 10.7±4.8 mm (lumbar)/9.2±4.9 mm (thoracic) respectively. A linear regression of the lumbar and thoracic curvatures between the marker-based measurements and MRI-based measurements resulted in coefficients of determination, R², of 0.552 and 0.385 respectively. Skin marker measurements therefore allow for the assessment of changes in the lumbar and thoracic curvature angles, but the absolute values suffer from uncertainty. Nevertheless, this marker set appears to be suitable for quantifying lumbar and thoracic spinal changes between quasi-static whole body postural changes.