Eye movements and verbal report in a single case of visual neglect

In this single case study, visuospatial neglect patient P1 demonstrated a dissociation between an intact ability to make appropriate reflexive eye movements to targets in the neglected field with latencies of <400 ms, while failing to report targets presented at such durations in a separate verbal detection task. In contrast, there was a failure to evoke the usually robust Remote Distractor Effect in P1, even though distractors in the neglected field were presented at above threshold durations. Together those data indicate that the tight coupling that is normally shown between attention and eye movements appears to be disrupted for low-level orienting in P1. A comparable disruption was also found for high-level cognitive processing tasks, namely reading and scene scanning. The findings are discussed in relation to sampling, attention and awareness in neglect.     

Leishmania mexicana: Inhibition of camptothecin-induced apoptosis of monocyte-derived dendritic cells

Macrophages (M?) and dendritic cells (DC) are the major target cell populations of the obligate intracellular parasite Leishmania. Inhibition of host cell apoptosis is a method employed by multiple pathogens to ensure their survival in the infected cell. Leishmania has been shown to protect M? and neutrophils from both natural and induced apoptosis. As shown in this study, apoptosis in monocyte-derived dendritic cells (moDC) induced by treatment with camptothecin was downregulated by coincubation with L. mexicana, as detected by morphological analysis of cell nuclei, TUNEL assay, gel electrophoresis of low molecular weight DNA fragments, and annexin V binding to phosphatidylserine. The observed antiapoptotic effect was found to be associated with a significant reduction of caspase-3 activity in moDC. The capacity of L. mexicana to delay apoptosis induction in the infected moDC may have implications for Leishmania pathogenesis by favoring the invasion of its host and the persistence of the parasite in the infected cells.     

Macrozoobenthos of two Antarctic glacial coves: a comparison with non-disturbed bottom areas

There are only few studies on shallow Antarctic benthic communities associated with habitats affected by intense mineral sedimentation inflow. The analysis of macrofaunal communities associated with two shallow, isolated glacial coves was performed in Admiralty Bay (King George Island) and compared with non-disturbed sites. Multivariate analyses (hierarchical classification, nMDS) clearly separated glacial cove communities (two assemblages) from the sites situated outside both basins (two assemblages). The community influenced by the streamflow of glacial discharge of meltwater situated in the area with sandy–clay–silt sediments had a very low species richness, diversity and abundance. It was dominated by eurytopic, motile deposit feeding polychaetes such as Mesospio moorei, Tharyx cincinnatus and Leitoscoloplos kerguelensis as well as the bivalve Yoldia eightsi. The second glacial community of the area located at a grater distance from the outlet of the stream was characterized by sandy–clay–silt and clay–silt deposits and showed also a low diversity and species richness. The most abundant here were peracarid crustaceans, with the dominant opportunistic feeder Cheirimedon femoratus. Community from the non-disturbed area with silty–clay–sand, and silty–sand sediments had higher species richness and diversity. The assemblage of fauna from the sandy bottom has values of those two indexes similar to those found in the disturbed areas.     

The Molecular Mechanism of Amyloid β42 Peptide Toxicity: The Role of Sphingosine Kinase-1 and Mitochondrial Sirtuins

Our study focused on the relationship between amyloid β 1–42 (Aβ), sphingosine kinases (SphKs) and mitochondrial sirtuins in regulating cell fate. SphK1 is a key enzyme involved in maintaining sphingolipid rheostat in the brain. Deregulation of the sphingolipid metabolism may play a crucial role in the pathogenesis of Alzheimer’s disease (AD). Mitochondrial function and mitochondrial deacetylases, i.e. sirtuins (Sirt3,-4,-5), are also important for cell viability. In this study, we evaluated the interaction between Aβ_1–42, SphKs and Sirts in cell survival/death, and we examined several compounds to indicate possible target(s) for a strategy protecting against cytotoxicity of Aβ_1–42. PC12 cells were subjected to Aβ_1–42 oligomers and SphK inhibitor SKI II for 24–96 h. Our data indicated that Aβ_1–42 enhanced SphK1 expression and activity after 24 h, but down-regulated them after 96 h and had no effect on Sphk2. Aβ_1–42 and SKI II induced free radical formation, disturbed the balance between pro- and anti-apoptotic proteins and evoked cell death. Simultaneously, up-regulation of anti-oxidative enzymes catalase and superoxide dismutase 2 was observed. Moreover, the total protein level of glycogen synthase kinase-3β was decreased. Aβ_1–42 significantly increased the level of mitochondrial proteins: apoptosis-inducing factor AIF and Sirt3, -4, -5. By using several pharmacologically active compounds we showed that p53 protein plays a significant role at very early stages of Aβ_1–42 toxicity. However, during prolonged exposure to Aβ_1–42, the activation of caspases, MEK/ERK, and alterations in mitochondrial permeability transition pores were additional factors leading to cell death. Moreover, SphK product, sphingosine-1-phosphate (S1P), and Sirt activators and antioxidants, resveratrol and quercetin, significantly enhanced viability of cells subjected to Aβ_1–42. Our data indicated that p53 protein and inhibition of SphKs may be early key events responsible for cell death evoked by Aβ_1–42. We suggest that activation of S1P-dependent signalling and Sirts may offer a promising cytoprotective strategy.     

Biogenic and Risk Elements in Wines from the Slovak Market with the Estimation of Consumer Exposure

Wine consumption delivers macroelements and microelements necessary for the proper metabolism. On the other hand, wine can be an important source of toxic metals. The aim of this study was to estimate the concentrations of Ca, Cd, Cu, Fe, Hg, Mg, Ni, Pb, and Zn in the Slovak and non-Slovak wines. The concentration of metals was evaluated with respect to the type, the alcohol content, and the age of Slovak wine. The general scheme of concentrations found was as follows Ca > Mg > Fe > Zn > Pb > Cd > Ni > Cu > Hg. The type of wine and the alcohol content do not have a significant impact on metal concentrations. Also, the age of wine has no influence on the mean concentration of metals, except for Zn. Metal concentrations in Slovak and non-Slovak wines indicate similar contents of metals, except for Ni. The contribution to both dietary reference values (DRVs) and provisional tolerable weekly intake (PTWI) evaluations in the Slovak wine suggested low dietary exposure to Ca, Cu, Fe, Mg, Ni, Zn, Cd, Hg, and Pb, respectively. However, we do not suggest that the consumption of all Slovak wines is healthy. The maximum Pb concentrations in Slovak wines exceed the maximum permitted level proposed by the European Commission. This might be proved by the results of the margin of the exposure (MOE) value evaluation in the samples containing the maximum Pb concentrations, showing a high risk of CKD and SBP in high and extreme consumption groups.     

Enhanced proliferation of cultured human vascular smooth muscle cells linked to increased function of RNA-binding protein HuR

In dividing cells, the RNA-binding protein HuR associates with and stabilizes labile mRNAs encoding proliferative proteins, events that are linked to the increased cytoplasmic presence of HuR. Here, assessment of HuR levels in various vascular pathologies (intimal hyperplasia, atherosclerosis and neointimal proliferation, sclerosis of arterialized saphenous venous graft, and fibromuscular dysplasia) revealed a distinct increase in HuR expression and cytoplasmic abundance within the intima and neointima layers. On the basis of these observations, we postulated a role for HuR in promoting the proliferation of vascular smooth muscle cells. To test this hypothesis directly, we investigated the expression, subcellular localization, and proliferative influence of HuR in human vascular smooth muscle cells (hVSMCs). Treatment of hVSMCs with platelet-derived growth factor increased HuR levels in the cytoplasm, thereby influencing the expression of metabolic, proliferative, and structural genes. Importantly, knockdown of HuR expression by using RNA interference caused a reduction of hVSMC proliferation, both basally and following platelet-derived growth factor treatment. We propose that HuR contributes to regulating hVSMC growth and homeostasis in pathologies associated with vascular smooth muscle proliferation.     

Monoclonal antibody against a cell wall marker protein for embryogenic potential of <Emphasis Type="Italic">Dactylis glomerata</Emphasis> L. suspension cultures

We identified and isolated a monoclonal antibody (MAb 3G2) raised against extracellular proteins from microcluster cells of orchard grass (Dactylis glomerata L.) embryogenic suspension culture. MAb 3G2 recognized with high specificity an antigen ionically bound within the primary cell wall and in the culture medium of microcluster cells. Two-dimensional polyacrylamide gel analysis and blotting of proteins on PVDF membrane showed that MAb 3G2 detected a single polypeptide of apparent molecular mass of 48 kDa and an isoelectric point (pI) of 5.2, designated EP48. A transient expression during somatic embryogenesis was observed for EP48. Indirect immunofluorescence showed that this protein highly accumulated in the cell walls of some single cells, microclusters and partly in proembryogenic masses (PEMs), but not in globular embryos of the embryogenic cell line and microclusters from the non-embryogenic cell line. Signal intensity varied between individual cells of the same population and in successive stages of somatic embryo development. Screening of several D. glomerata L. embryogenic and non-embryogenic cell lines with MAb 3G2 indicated the presence of ECP48 in only embryogenic suspension cultures at early stages of embryo development long before morphological changes have taken place and thus it could serve as an early marker for embryogenic potential in D. glomerata L. suspension cultures.     

Growth,phenology, and biomass allocation of alien Solidago species in central Europe

Plant invasion is a major threat to the integrity of an ecosystem. Exceptionally successful invaders in Europe are the American species of Solidago genus. In this study we examined growth, reproduction, and phenology of Solidago species, of American origin, growing in central Europe (S. altissima, S. canadensis, S. gigantea, S. graminifolia). These taxa were compared with two native species: Solidago virgaurea and Tanacetum vulgare. We observed high differentiation in height, number of shoots, and biomass production between individuals within taxa. Generally, the invasive species produced substantially (two to five times) more biomass than the native ones, being statistically significant in the comparison of alien Solidago graminifolia and S. gigantea versus native S. virgaurea and T. vulgare. The ratio of biomass of reproductive parts to overall biomass varied considerably among years, but generally the lowest one was for Solidago altissima, and the highest for S. graminifolia. It shows a lack of a clear pattern of differentiation between alien and native species in terms of biomass investment in reproduction. We observed a general tendency of allocation of a major part of biomass in rhizomes by phalanx species (S. graminifolia and S. gigantea), while species with guerrilla strategy (S. altissima and S. canadensis) invested more biomass in stems and leaves. However, because of the high variability there was no clear, stable pattern of statistically significant differences between these two groups. The results suggest that S. graminifolia reveals a strong potential of invasion, in spite of its, so far limited, distribution in Europe.