Effects of substratum restoration on salmonid habitat quality in a subalpine stream

Stream substratum restoration is a widely applied tool to improve spawning habitat quality for salmonid fishes. However, there is a lack of studies which comprehensively assess effects of the restoration on site, as well as on downstream habitats. Our study addressed effects at both locations and compared abiotic (analyses of texture, penetration resistance, oxygen concentration, redox, nitrite, nitrate, ammonium, pH, electric conductivity, temperature) with biotic (depth-specific macroinvertrebrate abundance and diversity, brown trout hatching success) indicators before and after excavation of the substratum in a highly colmated brown trout spawning site. Strong improvements of hyporheic water conditions (increased oxygen supply and redox potential, reduced concentrations of nitrite and ammonium) as well as ~50 % reductions of substratum compaction and fine sediment content were observed 1 day after the restoration measure. Improvements of habitat quality were still detectable 3 months after treatment. Consequently, the hatching success of Salmo trutta eggs increased from 0 % to 77 % after the restoration. Short-term decrease of macroinvertebrate abundance (from 13.1 to 3.9 macroinvertebrates/kg substratum) was observed within the hyporheic zone of the restoration site, but after 3 months, the number of taxa increased from 13 to 22 taxa and abundance reached 17.9 macroinvertebrates/kg. Significantly increased fine sediment deposition was detected within 1 km downstream of the restoration site and may negatively affect these habitats. Trade-offs between positive effects at restored sites and negative effects in downstream habitats need to be considered for a comprehensive evaluation of stream substratum restoration.     

Analysis of omega-3 and omega-6 fatty acid-derived lipid metabolite formation in human and mouse blood samples

Mass spectrometry techniques have enabled the identification of different lipid metabolites and mediators derived from omega-6 and omega-3 polyunsaturated fatty acids (n-6 and n-3 PUFA) that are implicated in various biological processes. However, the broad-spectrum assessment of physiologically formed lipid metabolites and mediators in blood samples has not been presented so far. Here lipid mediators and metabolites of the n-6 PUFA arachidonic acid as well as the long-chain n-3 PUFA eicosapentaenoic acids (EPA) and docosahexaenoic acid (DHA) were measured in human blood samples as well as in mouse blood. There were detectable but mostly very low amounts of the assayed compounds in human native plasma samples, whereas in vitro activation of whole blood with the calcium ionophore A23187 led to highly significant increases of metabolite formation, with a predominance of the 12-lipoxygenase (12-LOX) products 12-hydroxyeicosatetraenoic acid (12-HETE), 12-hydroxyeicosapentaenoic acid (12-HEPE) and 14-hydroxydocosahexaenoic acid (14-HDHA). A23187 activation also led to significant increases in the formation of 5-LOX products including leukotriene B(4) (LTB(4)), leukotriene B(5) (LTB(5)) as well as of 15-LOX products and prostaglandin E(2) (PGE(2)) and thromboxane B(2) (TXB(2)). Levels were similar or even higher in A23187-activated mouse blood. The approach presented here thus provides a protocol for the comprehensive and concomitant assessment of the generation capacity of n-3 and n-6 PUFA-derived lipid metabolites as well as thromboxanes and prostaglandins in human and murine blood samples. Further studies will now have to evaluate lipid metabolite generation capacity in different physiological and pathophysiological contexts.     

Ethacrynic acid analogues lacking the α,β-unsaturated carbonyl unit—Potential anti-metastatic drugs

A series of ethacrynic acid analogues, lacking the α,β-unsaturated carbonyl unit, was synthesized and subsequently evaluated for their ability to inhibit the migration of human breast cancer cells, MCF-7/AZ. Several of the analogues were already active in the low micromolar range, whereas ethacrynic acid itself shows no potential to inhibit the migration of these cancer cells. Preliminary studies show that the presence of one or more methoxy groups at the phenyl ring of ethacrynic acid is important in order for the ethacrynic acid analogues to demonstrate an inhibitory effect on the migration.     

Shift of aberrant antigen expression at relapse or at treatment failure in acute leukemia

The flow cytometric detection of aberrant antigen expression is one method proposed for the quantification of minimal residual disease (MRD) in acute leukemias. The present study was designed to investigate the stability of the aberrant antigen expression at relapse or at treatment failure of initial chemotherapy. For this purpose, multiparameter immunophenotyping with a panel of 15 monoclonal antibodies was used at diagnosis as well as at relapse (43 patients with overall 65 aberrations) and at treatment failure (35 patients with overall 66 aberrations). There was a significant decrease in the percentage of the initially described aberrant antigen expression on leukemia blasts at relapse (P = 0.001; n = 65) as well as at treatment failure (P = 0.0001; n = 66) considering all aberrations in the whole leukemia population. Concerning only patients with acute myelogenous leukemia (AML), significant decreases in the aberrant expression could be detected at relapse (P = 0.031; n = 42) and at treatment failure (P = 0.0001; n = 52). The changes in patients with acute lymphoblastic leukemia (ALL) were significant only at relapse (P = 0.006; n = 23). Initially, the most informative aberration was not detectable in four patients at relapse and in seven patients at treatment failure. A decrease of under 50% of the initial value was observed in another 8 patients at relapse and in 10 patients at treatment failure. In further studies assessing the detection of aberrant antigen expression for MRD, quantification of the relapses should be explicitly analyzed regarding the persistence of the initially described aberrant antigen expression.     

Differential expression of methyl CpG-binding domain containing factor MBD3 in the developing and adult rat brain

Using subtractive hybridization screening, the methyl CpG-binding domain containing protein MBD3 was identified as being more prevalently expressed in the embryonic brain than in the adult. In this report, we present the mRNA and protein expression patterns of MBD3 in the developing brain. MBD3 expression was detected in neuroepithelial cells of the developing forebrain, and in peripheral tissues such as liver and intestine during late embryogenesis. This is in contrast to its related family member MBD2, which displayed only minimal expression in the embryonic brain. Immunoblot analysis revealed that the levels of both MBD3 splice forms decrease in the maturing postnatal hippocampus and cortex, although the two forms do not decline at equivalent rates. Immunohistochemical analysis revealed strong MBD3 immunostaining in principal neurons of the hippocampus and cortex, but weak or nondetectable immunostaining in outer cortical layer cells. MBD3 was also selectively expressed in the adult retina, where strong immunoreactivity was detected in cells of the inner nuclear and ganglion cell layers, but no immunoreactivity was detected in cells of the outer nuclear layer. Taken together, these results illustrate that MBD3 displays a selective spatial and temporal pattern of expression in the embryonic and adult brain, thereby strengthening the possibility of MBD3 playing an important role in neuronal development.     

Expression and shedding of endothelial protein C receptor in prostate cancer cells

Background  

Increasing evidences show that beyond its role in coagulation, endothelial protein C receptor (EPCR) interferes with carcinogenesis. Pro-carcinogenic effects of EPCR were linked with a raised generation of activated protein C (aPC) and anti-apoptotic signalling. This study was carried out to analyze the expression, cell surface exposition, and shedding of EPCR in normal and malignant prostate cell lines.     

The glyoxalase system of malaria parasites--implications for cell biology and general glyoxalase research

Malaria parasites of the genus Plasmodium have developed sophisticated mechanisms to benefit from the nutrient-rich environments of their hosts. For example, by hiding in red blood cells, they found a secure way to tap into the glucose supply of vertebrates. The high-power metabolism of Plasmodium leads not only to a significantly increased glucose consumption of infected erythrocytes, but also to an elevated production of D-lactate from methylglyoxal. The latter substance is a harmful by-product from glycolysis that is detoxified by the ubiquitous glyoxalase system. This system consists of reduced glutathione and two enzymes, the glyoxalases 1 and 2. Inhibition of the glyoxalases in the host/parasite unit is expected to be highly detrimental to the parasite. Moreover, by studying Plasmodium isozymes, physiological functions of the system beyond methylglyoxal conversion became prima facie obvious: (i) the two different active sites of glyoxalase 1 as well as the existence of (insular) glyoxalases in the apicoplast point to alternative substrates and metabolic pathways. (ii) The allostery of glyoxlase 1 and the monomer-dimer equilibrium of glyoxalase 2 suggest novel regulatory features of these enzymes. Here we review the current knowledge on the glyoxalase systems of the host/parasite unit, discuss their potential as drug target and summarize new hypotheses on glyoxalases with respect to general cell biology.     

Systemic Agrobacterium tumefaciens-mediated transfection of viral replicons for efficient transient expression in plants

Plant biotechnology relies on two approaches for delivery and expression of heterologous genes in plants: stable genetic transformation and transient expression using viral vectors. Although much faster, the transient route is limited by low infectivity of viral vectors carrying average-sized or large genes. We have developed constructs for the efficient delivery of RNA viral vectors as DNA precursors and show here that Agrobacterium-mediated delivery of these constructs results in gene amplification in all mature leaves of a plant simultaneously (systemic transfection). This process, called "magnifection", can be performed on a large scale and with different plant species. This technology combines advantages of three biological systems (the transfection efficiency of A. tumefaciens, the high expression yield obtained with viral vectors, and the post-translational capabilities of a plant), does not require genetic modification of plants and is faster than other existing methods.