Fluoreszenzmarkierung von Tumor- und Leber-DNS der Ratte

Zusammenfassung Es wird eine Methode zur Fluoreszenzmarkierung von DNS, die aus Guérin-Rattentumoren und Rattenlebern isoliert wurde, mitgeteilt. Zur Kopplung wurde 1-Dimethylamino-naphthalin-sulfochlorid-5 (DIS) verwendet. Die Ratten intravenös applizierte markierte DNS stellt sich im Gewebsschnitt durch ihre gelbe bzw. intensiv gelbgrüne Fluoreszenz dar.

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Summary This paper informs of a method of fluorescence marking of DNA isolated from Guérin rat tumors and rat livers. For coupling we used 1-dimethylaminonaphthalene-sulphochloride-5 (DIS). The marked DNA injected intravenously into rats presented itself by yellow or intense yellowish green fluorescence.

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Zum hundertjährigen Bestehen des Lehrstuhls für Pathologie der Universität Rostock.     

In vitro shoot regeneration of Populus deltoides: effect of cytokinin and genotype

Treatment differences were observed in the in vitro adventitious shoot regeneration response from internodal explants of three genotypes of Populus deltoides cultured on media supplemented with five concentrations each of the cytokinins 6-benzyladenine, 2-isopentyladenine, and zeatin. For each of the three genotypes, the greatest number of shoots were consistently regenerated on media containing the cytokinin zeatin. Tissue necrosis resulted when explants from any of the three genotypes were cultured on media supplemented with 6-benzyladenine. A zeatin concentration by genotype interaction was also observed. Genotypic differences in shoot regeneration were observed for 16 genotypes of Populus deltoides when cultured on medium supplemented with 0.5 mgL^–1 zeatin. Six genotypes were highly recalcitrant and failed to regenerate shoots. The percent of explants regenerating was greater than 50% for four genotypes.Abbreviations WNA modified Woody Plant Media - BA N⁶-benzyladenine - 2-iP 2-isopentenyladenine - 2,4-D 2,4-dichlorophenoxyacetic acid - IBA indole-3-butyric acid - MS Murashige Skoog (1962) medium - NAA 1-naphthaleneacetic acid - PAR photosynthetically active radiation Journal Series No. 8938, Agricultural Research Division, University of Nebraska     

Effects of seven different mutations in the pho1 gene on enzymatic activity, glycosylation and secretion of acid phosphatase in Schizosaccharomyces pombe

Summary Structural gene mutants of the cell-surface glycoprotein acid phosphatase of Schizosaccharomyces pombe were analysed to define structural determinants that are responsible for enzymatic activity, N-glycosylation and secretion. All seven defined mutations cause a single amino acid substitution in the mature acid phosphatase protein and destroy the enzymatic activity. The mutational lesions are distributed throughout the pho1 gene. A ser to phe substitution at position 349 abolishes enzymatic activity only and does not affect glycosylation and secretion. Two mutations create a new N-glycosylation site by substitution of pro at position 56 by phe and ser, respectively. This new site is apparently used in the mutants. Their core-glycosylated acid phosphatase is slightly larger than that of the wild type. Overglycosylation seems not to affect secretion. Four different mutations (a gly to asp substitution at position 281 and ser to phe substitutions at positions 150, 271 and 277) cause intracellular accumulation of enzymatically inactive core-glycosylated acid phosphatase precursor. These mutational lesions apparently block transport of acid phosphatase from the endoplasmic reticulum to the Golgi apparatus.     

Mivazerol, a Novel α2-Agonist and Potential Anti-Ischemic Drug, Inhibits KCl-Stimulated Neurotransmitter Release in Rat Nervous Tissue Preparations

Abstract: In this study, we have investigated the effect of mivazerol, [3-(1H-imidazol-4-yl)methyl-1]-2-hydroxy-benzamide hydrochloride, a new α₂-agonist lacking hypotensive properties and a potential anti-ischemic drug, on the evoked release of norepinephrine, aspartate, and glutamate in tissue preparations from hippocampus, spinal cord T1–T5 section, rostrolateral ventricular medulla, and nucleus tractus solitarii of the brainstem of rat. A simple and efficient in vitro procedure to study pharmacologically the release of norepinephrine and glutamate is described. Tissues were chopped into (0.3 × 0.2 × 0.2 mm³) sections and the resulting minces were used for this study. Exposure to KCl (10–75 mM) for 5 min served as a stimulus for the release response. One, S (for aspartate and for glutamate release), or two such stimuli, S₁ and S₂ (for norepinephrine release) were conducted. The release of norepinephrine (+150% above baseline) was inhibited in a dose-dependent manner by mivazerol in hippocampus (IC₅₀ = 1.5 × 10^?8M), spinal cord (IC₅₀ = 5 × 10^?8M), rostrolateral ventricular medulla (IC₅₀ = 10^?7M), and nucleus tractus solitarii (IC₅₀ = 7.5 × 10^?8M), and by clonidine in hippocampus (IC₅₀ = 5 × 10^?8M), spinal cord (IC₅₀ = 4.5 × 10^?8M), rostrolateral ventricular medulla (IC₅₀ = 2.5 × 10^?7M), and nucleus tractus solitarii (IC₅₀ = 10^?7M). This effect was counteracted by the selective α₂-antagonists yohimbine and rauwolscine. A significant glutamate and aspartate release response was also induced by KCl (35 mmol/L) in hippocampus (+250 and +135%, respectively) and spinal cord (+120 and +55%, respectively), in vitro. However, neither mivazerol nor clonidine, at doses up to 10 µM, had any significant effect on KCl-induced glutamate release in spinal cord, whereas mivazerol blocked completely the release of both amino acids in hippocampus and only the release of aspartate in spinal cord. On the other hand, clonidine (1 µM) was only effective in reducing by 40% the release of aspartate in hippocampus. These data indicate that (1) inhibition of KCl-induced norepinephrine release by mivazerol is mediated by its action on α₂-adrenergic receptors; (2) at concentrations selective for α₂-adrenergic receptors, only mivazerol was effective in blocking the KCl-induced glutamate release in hippocampal tissue; and (3) at the same concentrations, both mivazerol and clonidine were unable to inhibit glutamate release in the spinal cord. These data suggest that prevention of hyperadrenergic activity by mivazerol in perioperative patients may be mediated through its effect on the release of norepinephrine and/or the release of glutamate and aspartate in regions of the CNS that are involved in the control of cardiovascular homeostasis.     

Identification of mutations in the ALD-gene of 20 families with adrenoleukodystrophy/adrenomyeloneuropathy

Adrenoleukodystrophy (ALD), an X-linked inherited metabolic disorder, is the most frequent inborn peroxisomal disease. It leads to demyelination in the central and peripheral nervous system. Defective -oxidation of saturated very long chain fatty acids (VLCFAs; C22:0–C26:0) in peroxisomes has been shown to lead to an accumulation of VLCFAs in leukoid areas of the central nervous system, peripheral nerves, adrenal gland, and blood. The ALD gene has been recently identified and encodes a 745-amino-acid protein. We screened patients with adrenoleukodystrophy/adrenomyeloneuropathy (ALD/AMN) from 20 kindreds for mutations in the ALD gene. Eleven missense and two nonsense mutations, five deletions, and one insertion were detected by direct sequencing of eight reverse transcribed fragments of the ALD-gene mRNA. Four mutations could be shown to be de novo. All mutations could be confirmed in carriers by sequencing genomic DNA. No correlation between the type of mutation and the severity of the phenotype could be observed. The mutations were not detected in the ALD gene of 30 healthy persons.     

Water and solute transport along developing maize roots

Hydraulic and osmotic properties were measured along developing maize (Zea mays L.) roots at distances between 15 and 465 mm from the root tip to quantify the effects of changes in root structure on the radial and longitudinal movement of water and solutes (ions). Root development generated regions of different hydraulic and osmotic properties. Close to the root tip, passive solute permeability (root permeability coefficient, P_sr) was high and selectivity (root reflection coefficient, _sr) low, indicative of an imperfect semipermeable root structure. Within the apical 100–150 mm, P_sr decreased by an order of magnitude and _sr increased significantly. Root hydraulic conductivity (Lp_r) depended on the nature of the force (hydrostatic and osmotic). Osmotic Lp_r was smaller by an order of magnitude than hydrostatic Lp_r and decreased with increasing distance from the root tip. Throughout the root, responses in turgor of cortical cells and late metaxylem to step changes in xylem pressure applied to the base of excised roots were measured at high spatial resolution. The resulting profiles of radial and longitudinal propagation of pressure showed that the endodermis had become the major hydraulic barrier in older parts of the root, i.e. at distances from the apex ä 150 mm. Other than at the endodermis, no significant radial hydraulic resistance could be detected. The results permit a detailed analysis of the root's composite structure which is important for its function in collecting and translocating water and nutrients.Abbreviations and Symbols CPP cell pressure probe - IT root segments with intact tips; - Lp_r root hydraulic conductivity - Lp_rh hydrostatic hydraulic conductivity of root - Lp_ro osmotic hydraulic conductivity of root - P_app hydrostatic pressure applied to cut end of root - P_c cell turgor - P_{c, cor} turgor of cortical cell - P_c,xyl turgor of late metaxylem vessel - P_ro stationary root pressure - P_r0,seal stationary root pressure of sealed root segment - P_sr solute permeability coefficient of root - RPP root pressure probe - TR root segments with tip removed - _sr reflection coefficient of root Dedicated to Professor Andreas Sievers on the occasion of his retirement     

Hormonal regulation of iron-stress response in sunflower roots: a morphological and cytological investigation

Summary Sunflowers are known to respond to Fe deficiency (-Fe) with a typical root tip swelling and the formation of root hairs and transfer cells in the rhizodermis. The possible regulation of this process was examined by a comparative study of root morphology and cytology of intact seedlings (Helianthus annuus L. cv. Giganteus) under -Fe and hormonal treatment in nutrient solution. Longitudinal sections of -Fe roots showed root tip swelling is due to cessation of cell elongation and isodiarnetric volume increase of the cortical cells. Enhanced cell division in the pericycle leads to the formation of lateral root primordia in the swollen zone. Xylem vessel differentiation is markedly accelerated and accompanied by early differentiation of the casparian band in the endodermis. Exogenous application of IAA (10^–8-10^–7 M) via the nutrient solution to Fe sufficient plants causes symptoms which closely mimick the characteristics of Fe deficiency including root hair development. Moreover, rhizodermal cells produce peripheral protuberances reminiscent of -Fe transfer cells. Ethylene-releasing ethephon (10^–4M) also causes subapical swelling and root hair formation. However, wall protuberance development is less pronounced. ABA (10^–5 M) leads to similar root thickening and root hair formation but without any comparable transfer cell differentiation. From the striking similarities between -Fe and IAA treatment it is concluded that this hormone (possibly in cooperation with ethylene) is involved in the Fe stress response of sunflower roots. The importance of a continuous polar IAA transport for this process is discussed.Abbreviations ABA abscisic acid - ACC 1-aminocyclopropane-1-carboxylic acid - Ethephone 2-chloro-ethylphosphonic acid - Fe(III)-EDTA ethylenediaminetetraacetic ferric-sodium salt - IAA indole-acetic acid - TIBA triiodobenzoic acid