Cell adhesion and integrin expression are modulated by oxidative stress in EA.hy 926 cells

The effects of oxidative stress on integrin-mediated cell adhesion to the extracellular matrix (ECM) and related apoptosis were investigated using the EA.hy926 endothelial cells treated (or not) with two oxidants: the hypoxanthine/xanthine oxidase system (HX/XO) or the tert-butyl hydroperoxide (t-BHP) which both increased cell apoptosis. Cell adhesion onto vitronectin (Vn) and fibronectin (Fn) was increased at low concentrations of HX/XO (up to 5 mU/ml) or t-BHP (up to 125 μM) and prevented ROS-induced apoptosis. Flow cytometry analysis of integrin expression showed that the expression of integrin αv and α5 subunits was, respectively, increased and decreased. Cell adhesion inhibition experiments using function-blocking monoclonal antibodies against integrin subunits indicated that αvβ1 and αvβ3 integrins were involved in adhesion of cells to Vn, and αvβ3 integrin played a major role in oxidant-treated cells. For adhesion to Fn, α5β1 and αvβ1 integrins were required for oxidant-treated cells. Taken together, the results suggest that reactive oxygen species (ROS) produced either by HX/XO or t-BHP could affect expression and/or activation of specific integrins in the interaction of EA.hy926 cells with ECM.     

Consequential LCA of switching from maize silage-based to grass-based dairy systems

Purpose

This study aimed to investigate the environmental consequences (on climate change and land use) of an increase in preference for grass-based milk in France using a consequential life cycle assessment (CLCA) approach. This increase in preference was assumed to be satisfied domestically, by converting maize silage-based dairy farms (MS farm) to grass-based dairy farms (G farm) while keeping on-farm usable agricultural area and total milk production of farm constant.

Methods

The possible consequences of an increase in preference for grass-based milk were identified based on cause and effect relationships. The conversion from MS to G farm reduced the use of soybean meal, changed the on-farm cropping pattern and produced more animals but less wheat and no rapeseed. Effects on on-farm soil C were predicted with the RothC model and on global land use change (LUC) with models of global agricultural markets (Global Trade Analysis Project (GTAP) and Landbouw Economisch Instituut Trade Analysis Project (LEITAP)). System expansion using animals from a suckler beef production system was applied to estimate the impacts of milk and animal co-products from the dairy system. Land occupation and climate change impacts were estimated. The consequences of farm conversion were attributed only to the milk, as preference for grass-based milk drove the conversion process.

Results and discussion

The conversion from the MS to G farm increases land occupation and climate change impacts for the G farm, respectively, by 9 and 7 % according to GTAP and 14 and 51 % according to LEITAP. Land occupation and climate change impacts of milk produced by the G farm after conversion increased, respectively, by 82 and 13 % with GTAP and 123 and 97 % with LEITAP relative to those for the MS farm (before conversion). The production of additional wheat and rapeseed outside the G farm increased impacts of the G farm (by 29–69 % depending on impacts and model used). Results indicate that the farm conversion would probably have consequences on global LUC and that it is important to account for this in a LCA approach.

Conclusions

Land use and land use change (LULUC) contributed to the impacts of grass-based milk, and results were highly sensitive to the LULUC model used. The many possible chain-of-event pathways that follow a change in preference for a given product yield high uncertainty in CLCA results. This study only assessed one possible way to meet the increase in preference for grass-based milk; it is necessary to perform a sensitivity analysis to investigate other possible scenarios resulting from this increase in preference.     

Human skin cell stress response to GSM-900 mobile phone signals. In vitro study on isolated primary cells and reconstructed epidermis

In recent years, possible health hazards due to radiofrequency radiation (RFR) emitted by mobile phones have been investigated. Because several publications have suggested that RFR is stressful, we explored the potential biological effects of Global System for Mobile phone communication at 900 MHz (GSM-900) exposure on cultures of isolated human skin cells and human reconstructed epidermis (hRE) using human keratinocytes. As cell stress markers, we studied Hsc70, Hsp27 and Hsp70 heat shock protein (HSP) expression and epidermis thickness, as well as cell proliferation and apoptosis. Cells were exposed to GSM-900 under optimal culture conditions, for 48 h, using a specific absorption rate (SAR) of 2 W x kg(-1). This SAR level represents the recommended limit for local exposure to a mobile phone. The various biological parameters were analysed immediately after exposure. Apoptosis was not induced in isolated cells and there was no alteration in hRE thickness or proliferation. No change in HSP expression was observed in isolated keratinocytes. By contrast, a slight but significant increase in Hsp70 expression was observed in hREs after 3 and 5 weeks of culture. Moreover, fibroblasts showed a significant decrease in Hsc70, depending on the culture conditions. These results suggest that adaptive cell behaviour in response to RFR exposure, depending on the cell type and culture conditions, is unlikely to have deleterious effects at the skin level.     

Effects of NaCl on growth, water status, N2 fixation, and ion distribution in Pterocarpus officinalis seedlings

Pterocarpus officinalis (Fabaceae) dominates in the swamp forests of the Lesser Antilles, submitted to strong variations of soil salinity (30–445 mM). This study aimed to assess the effect of salinity on growth, nodulation, N₂ fixation, water status and ions content in P. officinalis and to clarify the mechanisms involved. Seedlings inoculated or not with two strains from areas of contrasting salinity levels (< to 50 or 445 mM) were watered with 0, 171 and 342 mM solutions of NaCl in greenhouse conditions. Non-inoculated seedlings were tolerant to a salinity of 171 mM, with no significant effect on seedling biomass. Evapotranspiration per unit of leaf area (E/TLa) remained unchanged at 171 mM. Maintenance of a constant E/TLa and especially the control of ion transport to the upper parts of the plant could explain seedling salt tolerance up to intermediate salinity conditions (171 mM). The two strains have a 99.8% genetic identity in spite of differences in their original habitats, this explaining the similar response of the symbiosis to salinity. The higher salt sensitivity of inoculated seedlings was linked to the sensitivity of both Bradyrhizobium strains (reduction of free-living cells) and to that of the nodulation process (fewer nodules and inhibition of N₂-fixation) to intermediate salinity.     

Evidence of lipofuscin and melanin in the brown body of the earthworm Eisenia fetida andrei

By means of histochemical and electron-microscopic techniques, two pigments were identified in the brown body of the earthworm Eisenia fetida andrei. Lipofuscin, often called the aging pigment, was the more abundant pigment and the first to be synthesized. Melanin was also found but was only present in the mature brown body. A computer-assisted image analysis was used to quantify the relative abundance of the two pigments at different stages of the formation of the brown body. A previous study showing phenoloxidase activity in the coelomocytes and the present demonstration of the ability of these cells to produce reactive oxygen systems when agglutinated can be correlated with the simultaneous presence of the two pigments in the brown body. The physiological significance of pigment synthesis by brown bodies is discussed with respect to the immune response in earthworms.     

High fragmentation characterizes tumour-derived circulating DNA

Background

Circulating DNA (ctDNA) is acknowledged as a potential diagnostic tool for various cancers including colorectal cancer, especially when considering the detection of mutations. Certainly due to lack of normalization of the experimental conditions, previous reports present many discrepancies and contradictory data on the analysis of the concentration of total ctDNA and on the proportion of tumour-derived ctDNA fragments.

Methodology

In order to rigorously analyse ctDNA, we thoroughly investigated ctDNA size distribution. We used a highly specific Q-PCR assay and athymic nude mice xenografted with SW620 or HT29 human colon cancer cells, and we correlated our results by examining plasma from metastatic CRC patients.

Conclusion/Significance

Fragmentation and concentration of tumour-derived ctDNA is positively correlated with tumour weight. CtDNA quantification by Q-PCR depends on the amplified target length and is optimal for 60–100 bp fragments. Q-PCR analysis of plasma samples from xenografted mice and cancer patients showed that tumour-derived ctDNA exhibits a specific amount profile based on ctDNA size and significant higher ctDNA fragmentation. Metastatic colorectal patients (n = 12) showed nearly 5-fold higher mean ctDNA fragmentation than healthy individuals (n = 16).