Search

From 1993 onwards, various policy measures aiming at reducing nitrogen (N) losses were introduced in Swiss agriculture. We studied the impact of these measures on nitrate leaching under arable land in the Fehraltorf catchment near Zurich. Because of the well-drained soils, the shallow water table and the intensive agricultural activity, the groundwater in this catchment is highly vulnerable to nitrate pollution. N fluxes and transformations on the field scale were simulated using the deterministic model LEACHMN. Following the calibration of the model with a dataset from a long-term lysimeter experiment, simulations were run for the period 1998-2003. As far as possible, field-specific management data from farmers' control sheets were used as input. Average nitrate leaching in the period 1998-2003 was estimated to amount to 39 kg N ha year. The conditions before the introduction of the policy measures were simulated in three scenarios with a higher use of both mineral N fertiliser and animal manure and 50% less or no catch crops. We found that lowering mineral N fertiliser and manure application by about 25% led to an average decrease in nitrate leaching of 10 kg N ha year. Doubling the catch crop area yielded a further decrease of 6 kg N ha year on average. Altogether, the implementation of reduced N fertiliser inputs and increased use of catch crops proved to be effective and led to a mean reduction in N leaching of 29% (16 kg ha year) for the arable land in the Fehraltorf catchment. [ABSTRACT FROM AUTHOR]

Abstract: We have introduced a heterologous coculture model between Ehrlich ascites tumor (EAT) and baby hamster kidney cells (PtK2), and we have studied the influence of PtK2 cells and their newly synthesized cholesterol on uptake and tumor cell proliferation. PtK2 cells produce about five times more cholesterol as compared to EAT cells, and they support tumor cell growth in coculture experiments. This growth stimulation is reduced by 80% when EAT cells are cultured in PtK2 cell-derived medium in the presence of a monoclonal anti-low-density lipoprotein receptor (anti-LDLr) antibody. Freshly synthesized cholesterol by PtK2 cells is taken up by EAT cells in a time-dependent manner amounting to a threefold increase after 24h. Alternatively, cholesterol transfer to EAT cells is decreased between 28% and 35%, when PtK2 cell cholesterol synthesis is inhibited in the presence of mevinolin, the specific inhibitor of the hydroxy-3-methyl-glutaryl-coenzyme A (HMG-CoA) reductase. Furthermore, lower levels of EAT cell LDL receptor induced by antisense technology reduces cholesterol uptake and cell proliferation. These data demonstrate a metabolic interaction between normal and tumor cells mediated via the exchange of cholesterol, an important membrane constituent. [Copyright &y& Elsevier]

Two-photon (TP) excitation (820–1150 nm) and emission (280–700 nm) spectra for the fluorescent proteins (FPs) ECFP, EGFPand EYFPproduced in human tumour cells were recorded. TP excitation spectra of pure and highly enriched samples were found to be more differentiated in comparison with their one-photon (OP) spectra. They exhibited more pronounced main and local maxima, which coincided among different purity grades within small limits. TP and OP emission spectra of pure and enriched samples were identical. However, in crude samples, excitation was slightly blue-shifted and emission red-shifted. The data indicate that both OP and TP excitation routes led to the same excited states of these molecules. The emission intensity is dependent on the pH of the environment for both types of excitation; the emission intensity maximum can be recorded in the alkaline range. Reconstitution of emission intensity after pH quenching was incomplete, albeit that the respective spectral profiles were identical to those prequenching. When emission data were averaged over the whole range of excitation, the resulting emission profile and maximum coincided with the data generated by optimal excitation. Therefore, out-of-maximum excitation, common practice in TP excitation microscopy, can be used for routine application. [ABSTRACT FROM AUTHOR]

Summary Two-photon absorption and emission spectra for fluorophores relevant in cell imaging were measured using a 45 fs Ti:sapphire laser, a continuously tuneable optical parametric amplifier for the excitation range 580–1150 nm and an optical multichannel analyser. The measurements included DNA stains, fluorescent dyes coupled to antibodies as well as organelle trackers, e.g. Alexa and Bodipy dyes, Cy2, Cy3, DAPI, Hoechst 33342, propidium iodide, FITC and rhodamine. In accordance with the two-photon excitation theory, the majority of the investigated fluorochromes did not reveal significant discrepancies between the two-photon and the one-photon emission spectra. However, a blue-shift of the absorption maxima ranging from a few nanometres up to considerably differing courses of the spectrum was found for most fluorochromes. The potential of non-linear laser scanning fluorescence microscopy is demonstrated here by visualizing multiple intracellular structures in living cells. Combined with 3D reconstruction techniques, this approach gives a deeper insight into the spatial relationships of subcellular organelles. [ABSTRACT FROM AUTHOR]

In order to evaluate the possible role of the proteolytic enzyme cathepsin B (cath B) in human non-small cell lung cancer (NSCLC) we examined cath B concentrations (cath B[SUBc]) and activities (cath B[SUBA]) in homogenates of 127 pairs of lung tumour tissues and corresponding non-tumourous lung parenchyma. Total cath B activity (cath B[SUBAT]) and enzymatic activity of the fraction of cath B, which is stable and active at pH 7.5 (cath B[SUBA7.5]) were determined by a fluorogenic assay using synthetic substrate Z-Arg-Arg-AMC. The immunostaining pattern of cath B was determined in 239 lung tumour tissue sections, showing the presence of the enzyme in tumour cells (cath B[SUBT-I]) and in tumour-associated histiocytes (cath B[SUBH-I]). The median levels of cath B[SUBAT], cath B[SUBA7.5] and cath B[SUBC] were 5.6-, 3.2- and 9.1-fold higher (P < 0.001), respectively, in tumour tissue than in non-tumourous lung parenchyma. Out of 131 tissue sections from patients with squamous cell carcinoma (SCC), 59.5% immunostained positively for cath B, while among the 108 adenocarcinoma (AC) patients 48.2% of tumours showed a positive reaction. There was a strong relationship between the levels of cath B[SUBAT], cath B[SUBA7.5], cath B[SUBC] and cath B[SUBT-I] in the primary tumours and the presence of lymph node metastases. Significant correlation with overall survival was observed for cath B[SUBT-I] and cath B[SUBA7.5] (P < 0.01 and P < 0.05, respectively) in patients suffering from SCC. In these patients positive cath B in tumour cells (cath B[SUBT-I]) and negative cath B in histiocytes (cath B[SUBH-I]) indicated significantly shorter survival rate compared with patients with negative cath B[SUBT-I] and positive cath B[SUBH-I] (P < 0.0001). In contrast, in AC patients, both, positive cath B[SUBT-I] and positive cath B[SUBH-I], indicated poor survival probability (P < 0.014). From these results we conclude that the proteolytic enzyme cath B is an independent prognostic factor... [ABSTRACT FROM AUTHOR]

The rat tumor cell lines BSp73AS (AS, nonmetastasizing with pronounced adherent capacities) and BSp73ASML (ASML, highly metastasizing with reduced adherent capacities) were cytogenetically investigated. The ASML cell line.is reportedly derived from the AS cell line. Both lines exhibited abnormal numerical and structural chromosomal characteristics. The metastasizing ASML cells showed a higher chromosome number (modal number: 62-63) than the nonmetastasizing AS cells (modal number: 48). The AS karyotype was characterized by the presence of a large metacentric marker chromosome resulting from a Robertsonian translocation (Rb 6.7). This chromosome is as such absent in ASML cells but perhaps it may be present in these cells with a major part of chromosome 7 being deleted. The most interesting feature of the ASML karyo-type was the presence of double minutes (DMs) and a homogeneously staining region (HSR) at the telomeric end of chromosome 6. These were peculiar to the ASML cells, being absent in the AS cells. DMs and HSR are reported to be correlated with the resistance to various drugs and with the acquired virulence of tumor cells through gene amplification. Therefore, we assume that in the metastasizing ASML cell line the DMs and HSR were established through genetic selection and that they are probably related to the acquired metastasizing capacity of these cells. [ABSTRACT FROM AUTHOR]

A new genus of marine methanogenic bacteria and two species within this genus are described. Methanogenium is the proposed genus and Methanogenium cariaci the type species. Cells of the type species are Gram-negative, peritrichously flagellated, irregular cocci with a periodic wall surface pattern. Colonies formed by these bacteria are yellow, circular and umbonate with entire edges. The DNA base composition is 52 mol% guanine plus cytosine. Formate or hydrogen and carbon dioxide serve as substrates for growth. Cells of Methanogenium marisnigri are of similar shape but smaller diameter than M. cariaci. The colonies of M. marisnigri are convex, and the DNA base composition is 61 mol % G+C. Formate or hydrogen and carbon dioxide are growth substrates. Sodium chloride is required for growth of both methanogens. [ABSTRACT FROM AUTHOR]

Overlapping spreading centers (OSCs) are a type of ridge axis discontinuity found along intermediate and fast spreading centers. The ridges at these locations overlap and curve towards each other. and are separated by an elongate overlap basin. A high resolution Deep-Tow survey was conducted over the 12°54′ N OSC (offset ≈1.6 km) on the East Pacific Rise in order to study the structure of a small OSC on a fine scale. A detailed tectonic study and Deep-Tow 3-D magnetic inversion were performed on the data. Towards the tips of both limbs, the apparent age of lava flows increases, the density of exposed faults and fissures increases, and the axial graben loses definition and disappears. No active hydrothermal vents were detected in the area. These observations suggest that the magmatic budget steadily decreases along axis approaching and OSC, even where the offset is small. In contrast with OSCs which have a large offset (>5 km), the 3-D magnetic inversion solution for this OSC produced no evidence for highly magnetized areas near the tip of either spreading center. [ABSTRACT FROM AUTHOR]

Copyright of Archiv für Mikrobiologie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Archiv für Mikrobiologie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Archiv für Mikrobiologie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)