Immobilisation of phosphorus by iron-coated roots of submerged macrophytes

Hydrobiologia - To observe effects on the phosphorus retention mechanisms of a lake after re-colonisation by macrophytes, Potamogeton crispus L. and Elodea canadensis Michx. were planted in lab...     

Long-term effects of dietary isoflavones on uterine gene expression profiles

Isoflavones (ISOs) are bioactive food ingredients of the traditional East Asian diet and currently discussed as alternatives to classical hormone replacement therapies and for reducing the prevalence of hormone-dependent cancers. Although there are many studies on ISOs, not much is known about their long-term effects.Therefore, we performed an animal experiment analyzing the effects of three different diets: a phytoestrogen-free diet, a diet supplemented with genistein (700 μg/g diet) and an ISO-high diet (232 μg daidzein and 240 μg genistein/g) at two distinct time points, juvenile (21 days) and adult (97 days). Exposure started prior to mating of the parents and throughout the life of the offspring.We observed a stronger increase of uterine wet weights in juvenile offspring with genistein exposure (1018 ± 350 mg/kg BW) than with ISO-high diet (497 ± 133 mg/kg BW). Whereas the expression of proliferation related genes (PCNA; Ki67; IGF-1; IGF-1R), analyzed by real-time-qPCR and Western blot, were significantly down-regulated in juvenile animals exposed to genistein. Additionally, genistein exposure led to estrogenic responses, observed upon increase of complement C3 and decrease of estrogen receptors gene expressions, while the exposure to ISO-high diet did not show these effects.In conclusion, both the time point on which phytoestrogen exposure starts together with the composition of the ingested phytoestrogen containing diet are of great importance for the biological response of the offspring.     

Adhesion of canine and human uropathogenicEscherichia coli andProteus mirabilis strains to canine and human epithelial cells

Escherichia coli strains causing urinary tract infections in dogs produce fimbriae composed of fimbrial subunits closely related to the F12 and F13 fimbriae of human uropathogenic strains [4]. The adhesins carried by the fimbriae of human and canine isolates differ, however, as concluded from a different hemagglutination pattern and from the fact that the dog strains do not agglutinate latex beads coated with P-fimbriae receptor. This possible difference in adhesive specificity was confirmed by experiments in which the adhesion of human and dog isolates to dog kidney epithelial cells (MDCK cells) and human bladder epithelial cells (T24 cells) was compared. Dog uropathogenic strains, in contrast to human uropathogenicE. coli strains, adhere to MDCK cells but hardly to T24 cells. Adhesion to MDCK cells correlates with the presence of F12 or F13 fimbriae on the dog strains. These results suggest that homologous fimbrial subunits can carry different adhesin molecules and that these adhesin molecules can be responsible for species-specific adherence. On the contrary, adhesion of a number of dog uropathogenicProteus mirabilis strains to MDCK and T24 cells was not species specific; it depended on the mere presence of fimbriae.     

Über die elektronenmikroskopische Identifizierung von noradrenergen Nervenfasern durch 5-Hydroxydopamin und 5-Hydroxydopa im Pinealorgan der Eidechse (Lacerta muralis)

Zusammenfassung Durch Verwendung von 5-Hydroxydopamin und 5-Hydroxydopa, die endogenes Noradrenalin in den Speichergranula sympathischer Nerven ersetzen, gelang es, noradrenerge Nervenfasern innerhalb des Pinealorgans von Lacerta muralis zu identifizieren. Die Nerven stammen von sympathischen, autonomen Neuronen. Ihre marklosen Fortsätze können an der großen Anzahl von granulierten Vesikeln erkannt werden, deren elektronendichter Inhalt durch die Vorbehandlung eindeutig zugenommen hat. In drei Teilen des Pinealorgans wurden noradrenerge Fasern elektronenmikroskopisch gefunden: 1. Neben den Blutgefäßen im perivaskulären Bindegewebsraum, 2. zwischen den Zellen und deren Fortsätzen innerhalb des Pinealorgans, 3. frei im Lumen des Pinealorgans. In einigen Fällen wurde beobachtet, daß verdickte Endformationen Kontakt mit Teilen von Sinneszellen, besonders deren Außengliedern, aufnehmen. Bisher konnte kein synaptischer Kontakt mit sekretorischen Zellen des Pinealorgans festgestellt werden.

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On the electron microscopic identification of noradrenergic nerves in the pineal organ of the lizard lacerta muralis by 5-hydroxydopamine and 5-hydroxydopa

Summary Using 5-hydroxydopamine and5-hydroxydopa as false sympathetic transmitters the authors identified noradrenergic nerves inside the pineal organ of the lizard. These nerves are part of sympathetic autonomic neurones; their unmyelinated processes are identified by a large number of dense core vesicles the electron dense content of which has increased significantly following pretreatment with the catechol-analogues. There are three parts of the pineal organ where noradrenergic nerves have been found electron microscopically: 1) Close to the blood vessels in the perivascular connective tissue compartment, 2) between cells and their processes inside the epithelium of the pineal organ, 3) free in the lumen of the pineal gland. In some cases club shaped terminations contact parts of sensory cells especially their outer segments. No synaptic contacts to secretory cells have been detected so far.

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Supported by USPHS Research Grant TW 00295-02.

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Mit dankenswerter Unterstützung durch die Deutsche Forschungsgemeinschaft.     

Ultrastructural immunolocalization of periodic pectin depositions in the cell wall ofNicotiana tabacum pollen tubes

Summary The monoclonal antibody (MAb) JIM5, marking acidic pectins, was used to localize ultrastructurally pectin molecules in the pollen tube wall ofNicotiana tabacum. Longitudinal sections of LR-White embedded pollen tubes were exposed to antibody treatment; accumulations of pectins were identified by counting the density of the gold particles representing the pectin epitopes along the pollen tube wall. Significant accumulations of gold grains were marked and the distances between them were measured. In many pollen tubes a more or less regular distribution of the accumulations was observed along the tube indicating a periodical deposition of pectin. The distances between the accumulations were 4–6 m. Most of the label was found in the inner part of the outer layer of the bilayered cell wall. These findings correspond to and confirm the earlier observation by our group reporting ring-shaped periodical deposits in pollen tubes after immunofluorescence labelling with the MAb JIM5 under the confocal laser scanning microscope.Abbreviations Ab antibody - MAb monoclonal antibody     

Methane oxidation by methanotrophs and its effects on the phosphate flux over the sediment-water interface in a eutrophic lake

The effect of methane oxidation in aerobic sediment on oxygen consumption and phosphate flux was investigated in diffusion chambers. The diffusion chambers consisted of two compartments separated by a Teflon membrane. In the upper chamber a thin sediment layer was present and the lower chamber was continuously flushed with gas. The hydrophobic membrane allowed for diffusion of gases from the lower chamber through the sediment layer toward the headspace of the upper chamber. In experiments with a methane oxidation rate of 9.8 mmol m^–2 day^–1, the oxygen consumption rate increased by a factor of two compared with controls without methane oxidation (8.6 vs 17.7 mmol m^–2 day^–1). Methane oxidation significantly decreased oxygen penetration depth (2.5–4.0 vs 1.0–2.0 mm). However, despite the shrinkage of the oxidized microlayer, no differences were found in phosphate flux across the sediment water interface. Batch experiments with standard additions of methane revealed that the growth of methanotrophic bacteria contributes to the phosphate uptake of aerobic sediment. From the batch experiments a molar ratio of carbon to phosphate of 45 mol:mol was calculated for the growth of methanotrophs. Results suggest that a decrease in chemical phosphate adsorption caused by a decrease in the oxygen penetration depth could be compensated for entirely by the growth of methanotrophic bacteria. Send offprint requests to: A.J.C. Sinke