Apoptosis in bovine cumulus-oocyte complexes after exposure to polychlorinated biphenyl mixtures during in vitro maturation

Aroclor-1254 (A-1254) is a commercial mixture of coplanar (dioxin-like) and non-coplanar (non dioxin-like) polychlorinated biphenyls (PCBs) affecting bovine oocyte in vitro maturation (IVM) and developmental competence. In the present study, the role of cumulus cell apoptosis in mediating the toxic effects of PCBs during in vitro maturation has been investigated. Results indicate that exposure of cumulus-oocyte complexes (COCs) to A-1254 significantly induced apoptosis of cumulus cells. Furthermore, A-1254 significantly increased the expression of the pro-apoptotic gene, Bax, concomitantly reducing the level of the anti-apoptotic gene, Bcl-2, in the cumulus cell compartment. The effects of pure mixtures of coplanar (PCB 77, 126 and 169) or non-coplanar (PCB 52, 101 and 153) PCBs were examined. Exposure of COCs to coplanar PCBs affected maturation at doses as low as 100.6 pg/ml. Furthermore, a significant increase in apoptosis and in Bax mRNA expression was observed. No variations in maturation or apoptosis were observed in the non-coplanar PCB group. To further analyze the role of cumulus cells, COCs and denuded oocytes (DOs) have been exposed to A-1254 or coplanar PCBs during IVM. Exposure of COCs significantly reduced the percentage of matured oocytes after 24 h of culture in both treatments. In contrast, exposure of DOs significantly decreased the maturation rate only at the highest dose investigated (100-fold greater than that affecting COCs). Taken together, the results indicate a direct role of cumulus cell apoptosis in mediating PCB toxicity on bovine oocytes, and a direct relationship between congener planarity and toxicity in bovine oocytes is suggested.     

Opposite Modulation of Cell Migration by Distinct Subregions of Urokinase Connecting Peptide

Functional analysis of isolated protein domains may uncover cryptic activities otherwise missed. The serine protease urokinase (uPA) has a clear‐cut motogen activity that is catalytically independent and resides in its amino‐terminal growth factor domain (GFD, residues 1‐49) and connecting peptide region (CP, residues 132–158). To functionally dissect the CP region, we analysed the biological activity of two synthetic peptides corresponding to the N‐terminal [uPA‐(135–143), residues 135–143] and C‐terminal [uPA‐(144–158), residues 144–158] CP subregions. Most of the chemotactic activity of connecting peptide‐derived peptide (CPp, [uPA‐(135–158)]) for embryonic kidney HEK293/uPAR‐25 cells is retained by uPA‐(144–158) at nanomolar concentrations. In contrast, uPA‐(135–143) inhibits basal, CPp ‐, vitronectin‐ and fibronectin‐induced cell migration. Radioreceptor binding assays on intact HEK293 cells revealed that uPA‐(135–143) and uPA‐(144–158) are both able to compete with [¹²⁵I]‐CPp, albeit with different binding affinities. The consequences of phospho‐mimicking, S138E substitution, were studied using [138E]uPA‐(135–158) and [138E]uPA‐(135–143) peptides. Unlike CPp, [138E]uPA‐(135–158) and [138E]uPA‐(135–143) exhibit remarkable inhibitory properties. Finally, analysis of the conformational preferences of the peptides allowed to identify secondary structure elements exclusively characterising the stimulatory CPp and uPA‐(144–158) versus the inhibitory uPA‐(135–143), [138E]uPA‐(135–158) and [138E]uPA‐(135–143) peptides. In conclusion, these data shed light on the cryptic activities of uPA connecting peptide, revealing the occurrence of two adjacent regions, both competing for binding to cell surface but conveying opposite signalling on cell migration.     

Thin film silicon photovoltaics: Architectural perspectives and technological issues

Thin film photovoltaics is a particularly attractive technology for building integration. In this paper, we present our analysis on architectural issues and technological developments of thin film silicon photovoltaics. In particular, we focus on our activities related to transparent and conductive oxide (TCO) and thin film amorphous and microcrystalline silicon solar cells. The research on TCO films is mainly dedicated to large-area deposition of zinc oxide (ZnO) by low pressure-metallorganic chemical vapor deposition. ZnO material, with a low sheet resistance (<8 Ω/sq) and with an excellent transmittance (>82%) in the whole wavelength range of photovoltaic interest, has been obtained. “Micromorph” tandem devices, consisting of an amorphous silicon top cell and a microcrystalline silicon bottom cell, are fabricated by using the very high frequency plasma enhanced chemical vapor deposition technique. An initial efficiency of 11.1% (>10% stabilized) has been obtained.     

Up-Regulation of Cyclooxygenase-2 (COX-2) Expression by Temozolomide (TMZ) in Human Glioblastoma (GBM) Cell Lines

TMZ-resistance remains a main limitation in glioblastoma (GBM) treatment. TMZ is an alkylating agent whose cytotoxicity is modulated by O6-methylguanine-DNA methyltransferase (MGMT), whose expression is determined by MGMT gene promoter methylation status. The inflammatory marker COX-2 has been implicated in GBM tumorigenesis, progression, and stemness. COX-2 inhibitors are considered a GBM add-on treatment due to their ability to increase TMZ-sensitivity. We investigated the effect of TMZ on COX-2 expression in GBM cell lines showing different COX-2 levels and TMZ sensitivity (T98G and U251MG). β-catenin, MGMT, and SOX-2 expression was analyzed. The effects of NS398, COX-2 inhibitor, alone or TMZ-combined, were studied evaluating cell proliferation by the IncuCyte^® system, cell cycle/apoptosis, and clonogenic potential. COX-2, β-catenin, MGMT, and SOX-2 expression was evaluated by RT-PCR, Western blotting, and immunofluorescence and PGE2 by ELISA. Our findings, sustaining the role of COX-2/PGE2 system in TMZ-resistance of GBM, show, for the first time, a relevant, dose-dependent up-regulation of COX-2 expression and activity in TMZ-treated T98G that, in turn, correlated with chemoresistance. Similarly, all the COX-2-dependent signaling pathways involved in TMZ-resistance also resulted in being up-modulated after treatment with TMZ. NS398+TMZ was able to reduce cell proliferation and induce cell cycle arrest and apoptosis. Moreover, NS398+TMZ counteracted the resistance in T98G preventing the TMZ-induced COX-2, β-catenin, MGMT, and SOX-2 up-regulation.     

Effect of aw and CO2 level on Aspergillus flavus growth and aflatoxin production in high moisture maize post-harvest

The potential for using modified atmospheres of 25-75% CO2 (balanced with N2) and water activity (aw, 0.95, 0.92) to control Aspergillus flavus development and aflatoxin B1 production has been evaluated (a) on synthetic medium and (b) on maize grain during storage for up to 21 days at 25 degrees C. On agar medium up to 75% CO2 at both 0.95 and 0.92 aw significant inhibition of growth was obtained (P<0.05). In stored grain inoculated with spores of A. flavus there was significantly higher populations of the species at 0.95 aw than 0.92 aw. Up to 75% CO2 resulted in an inhibition of the populations of A. flavus isolated from the grain. Contrasting aflatoxin B1 production was obtained on agar and in stored maize grain. On agar, greatest amounts were produced at 0.92 aw, while more was produced at 0.95 aw on maize grain. Overall, the efficacy of controlled atmospheres x aw showed that treatment with 25% CO2 could be sufficient to efficiently reduce A. flavus development but at least 50% CO2 was required to obtain a significant reduction of aflatoxin synthesis.     

Casein phosphopeptides modulate calcium uptake and apoptosis in Caco2 cells through their interaction with the TRPV6 calcium channel

Dietary calcium intake is associated with colon cancer incidence due to its ability to modulate proliferation and apoptosis, cellular function directly linked to normal or tumour cell phenotype. In milk calcium is associated with casein whose hydrolysis produces the casein phosphopeptides (CPPs). CPPs induce calcium uptake in differentiated HT-29 and Caco2 cells. The aim of the present study was to explore: (i) the interaction between CPPs and the TRPV6 calcium channel in HT-29 and Caco2 cells; (ii) CPP effects on Caco2 cell functions. By reducing the expression of TRPV6 through small interfering RNA (siRNA), a decrease in cell response to CPPs was monitored in Caco2 cells (about 56%) but not in HT-29 cells. CPPs increased apoptosis both in undifferentiated and in transfected Caco2 cells. Based on the reported involvement of TRPV6 in cancer development, the results presented for CPPs may be helpful for their consideration as functional food ingredients.     

New Panx-1 Blockers: Synthesis,Biological Evaluation and Molecular Dynamic Studies

The channel protein Panx-1 is involved in some pathologies, such as epilepsy, ischemic stroke, cancer and Parkinson’s disease, as well as in neuropathic pain. These observations make Panx-1 an interesting biological target. We previously published some potent indole derivatives as Panx-1 blockers, and as continuation of the research in this field we report here the studies on additional chemical scaffolds, naphthalene and pyrazole, appropriately substituted with those functions that gave the best results as in our indole series (sulphonamide functions and one/two carboxylic groups) and in Panx-1 blockers reported in the literature (sulphonic acid). Compounds 4 and 13, the latter being an analogue of the drug Probenecid, are the most potent Panx-1 blockers obtained in this study, with I = 97% and I = 93.7% at 50 µM, respectively. Both compounds, tested in a mouse model of oxaliplatin-induced neuropathic pain, showed a similar anti-hypersensitivity profile and are able to significantly increase the mouse pain threshold 45 min after the injection of the doses of 1 nmol and 3 nmol. Finally, the molecular dynamic studies and the PCA analysis have made it possible to identify a discriminating factor able to separate active compounds from inactive ones.     

Bioactives Screening in Overripe Fruits and Vegetables by Liquid Chromatography Coupled to Photodiode Array and Mass Spectrometry Detection

Food waste production generated by large distribution represents an emerging issue due to the large polluting impact and, at the same time, due to the enormous increase of nutrients’ need worldwide. Overripe fruits are considered as “food wastes” despite they could be yet rich sources of food ingredients and bioactives, such as carotenoids and polyphenols. In this work, a phytochemical screening of 20 selected overripe vegetables and fruits was accomplished by liquid chromatography coupled to photodiode array and mass spectrometry detection. The obtained results showed that the low-sugar-content fruits and vegetables had a higher bioactive content compared to the high-sugar fruits; in particular, tomato, wild swiss chard, green bell pepper, and lettuce leaves were the richest in bioactive phytochemicals. Green bell peppers showed the highest pigment content (875.3 mg/kg), whereas tomato, wild swiss chard, and lettuce leaves showed the highest polyphenol contents, 4541.9, 1692.4, and 712.9 mg/kg, respectively. This is the first work where a large-scale monitoring of bioactives in overripe fruits was carried out and two mixtures of fresh and dry material for animal feed are presented.