477 research outputs found
[Uptake of L-(+)lactate by cell membrane (luminal and contraluminal) isolated from rat small intestine microvilli]
No full textThe role of potassium and chloride ions on the Na+/acidic amino acid cotransport system in rat intestinal brush-border membrane vesicles
No full textAnti-apoptotic effects of protein kinase C-δ and c-fos in cisplatin-treated thyroid cells
No full textBackground and purpose: We showed previously that cisplatin inititates a signalling pathway mediated by PKC-δ/extracellular signal-regulated kinase (ERK), important for maintaining viability in PC Cl3 thyroid cells. The studies described herein examined whether c-fos was associated with cisplatin resistance and the signalling link between c-fos and PKC-δ/ERK. Experimental approach: Cells were treated with various pharmacological inhibitors of PKCs and ERK, or were depleted of c-fos, PKC-δ, PKC-η and caspase-3 by small interfering RNA (siRNA), then incubated with cisplatin and cytotoxicity assessed. Key results: Cisplatin provokes the induction of c-fos and the activation of conventional PKC-β, and novel PKC-δ and -η. The cisplatin-provoked c-fos induction was decreased by Gö6976, a PKC-β inhibitor; by siRNA for PKC-δ- but not that for PKC-η or by PD98059, a mitogen-activated protein kinase/ERK kinase inhibitor. Expression of c-fos was abolished by GF109203X, an inhibitor of all PKC isoforms, or by PD98059 plus Gö6976 or by PKC-δ-siRNA plus Gö6976. When c-fos expression was blocked by siRNA, cisplatin cytotoxicity was strongly enhanced with increased caspase-3 activation. In PKC-δ-depleted cells treated with cisplatin, caspase-3 activation was increased and cell viability decreased. In these PKC-δ-depleted cells, PD98059 did not affect caspase-3 activation. Conclusions and implications: In PC Cl3 cells, in the cell signalling pathways that lead to cisplatin resistance, PKC-δ controls ERK activity and, together with PKC-β, also the induction of c-fos. Hence, the protective role of c-fos in thyroid cells has the potential to provide new opportunities for therapeutic intervention. © 2009 The British Pharmacological Society
Anti-apoptotic effects of protein kinase C-delta and c-fos in cisplatin-treated thyroid cells
No full textBackground and purpose: We showed previously that cisplatin inititates a signalling pathway mediated by PKC-delta/extracellular signal-regulated kinase (ERK), important for maintaining viability in PC Cl3 thyroid cells. The studies described herein examined whether c-fos was associated with cisplatin resistance and the signalling link between c-fos and PKC-delta/ERK. Experimental approach: Cells were treated with various pharmacological inhibitors of PKCs and ERK, or were depleted of c-fos, PKC-delta, PKC-epsilon and caspase-3 by small interfering RNA (siRNA), then incubated with cisplatin and cytotoxicity assessed. Key results: Cisplatin provokes the induction of c-fos and the activation of conventional PKC-beta, and novel PKC-delta and -epsilon. The cisplatin-provoked c-fos induction was decreased by Gö6976, a PKC-beta inhibitor; by siRNA for PKC-delta- but not that for PKC-epsilon or by PD98059, a mitogen-activated protein kinase/ERK kinase inhibitor. Expression of c-fos was abolished by GF109203X, an inhibitor of all PKC isoforms, or by PD98059 plus Gö6976 or by PKC-delta-siRNA plus Gö6976. When c-fos expression was blocked by siRNA, cisplatin cytotoxicity was strongly enhanced with increased caspase-3 activation. In PKC-delta-depleted cells treated with cisplatin, caspase-3 activation was increased and cell viability decreased. In these PKC-delta-depleted cells, PD98059 did not affect caspase-3 activation. Conclusions and implications: In PC Cl3 cells, in the cell signalling pathways that lead to cisplatin resistance, PKC-delta controls ERK activity and, together with PKC-beta, also the induction of c-fos. Hence, the protective role of c-fos in thyroid cells has the potential to provide new opportunities for therapeutic intervention
La città di Guidonia e il suo aeroporto nello sviluppo dell'Università degli Studi di Roma "La Sapienza"
No full textPotenzialità del ex Centro Studi ed Esperienze dell'Aeroporto di Guidonia in rapporto a nuovi insediamenti universitari della "Sapienza
Development of a new in vivo protocol through soil inoculation to investigate sugar beet resistance towards Ditylenchus dipsaci penetration
No full textThe stem nematode,Ditylenchus dipsaci, causes severe damage in sugar beet. To date, nematode inoculation throughthe leaf axil has been used as the standard method to investigateD. dipsaciinteraction with sugar beet underin vivoconditions. Toget as close as possible to field conditions, we established a new screening mechanism to perform soil inoculation. The most suitableinoculation time point, inoculum level and positioning on sugar beet, as well as rearing process on carrots, were determined. At a15:8°C day:night temperature regime, penetration rates ofD. dipsaciwere at maximum following soil inoculation at plant emergence.Up to 115 nematodes penetrated sugar beet seedlings 22 days post-planting with an inoculum level of 1000 nematodes into the soil atplant emergence.Ditylenchus dipsacipenetration rate was higher in plants with soil inoculation than with inoculation on to the leaf axil.High soil moisture increased nematode migration into seedlings whenD. dipsaciinoculation was carried out in four holes 1 cm fromthe plant base. Rearing the nematodes for 35 days at 20°C on carrot discs resulted in an infective inoculum containing up to 50% eggs.We recommend a soil inoculation of 1000 freshly extracted nematodes per pot at plant emergence. The nematode suspension has to bepreviously reared for 35 days on carrot discs to obtain activeD. dipsaciinoculum. This system will allow for the selection of suitablesugar beet genotypes that suppress nematode penetration, in support of breeding for resistance againstD. dipsaci
A simple and fast method for the isolation of basolateral plasma membranes from rat small-intestinal epithelial cells
No full textPCBs and PCDD/Fs in bluefin tuna: Occurrence and dietary intake
No full textPolychlorinated biphenyls (PCBs) and polychlorinated dibenzo-furans (PCDD/Fs) were measured in Mediterranean bluefin tuna (Thunnus thynnus) to verify the compliance with the EU regulations for food commercialization. The estimated intakes were also evaluated. The analyses were performed by gas chromatography-ion trap tandem mass spectrometry (GC-MS-MS). The PCBs were dominant (1132.0 ng g−1l.w.), followed by PCDFs (23.2 pg g−1l.w.) and PCDDs (8.5 pg g−1l.w.). The pollutant levels (dl-PCBs: 0.7 pg TEQ/g w.w.; PCDD/Fs: 1.9 pg TEQ/g w.w.) and their sum expressed as TEQ values (2.6 pg TEQ/g w.w.) remained below the limits for human consumption proposed by the European Union. On the contrary, the sum of the six indicator non-dioxin-like PCBs (84.2 ng g−1w.w.) was slightly above the maximum level fixed by the in-force legislation. The estimated dietary intakes for PCDD/Fs plus dl-PCBs were below the toxicological reference values (TRVs) set by various international bodies, while non-cancer and cancer risk assessment revealed a safety concern. Additionally, the estimated intake of ndl-PCBs exceeded the maximum levels set by different European countries. These findings suggest caution in tuna consumption together with an active and frequent surveillance of the chemical quality of its flesh
Na-dependent D-glucose and L-alanine transport in eel intestinal brush border membrane vesicles
No full textBrush border membrane vesicles (BBMV) were prepared from eel (Anguilla anguilla) intestine by a Mg-ethylene-glycol-bis(beta-aminoethylether)-N,N'-tetraacetic acid precipitation technique; the BBMV were enriched 16, 12, and 13 times in leucine aminopeptidase, maltase, and alkaline phosphatase activities with respect to the starting mucosal scraping. D-[3H]glucose and L-[3H]alanine transport by these vesicles was studied by a rapid filtration technique. D-Glucose uptake was stimulated by a transmembrane Na gradient but not by an identical Na gradient in the presence of phloridzin or by a choline gradient. The Na-dependent D-glucose uptake was increased by rendering the vesicle interior electrically negative, suggesting electrogenic cotransport of the sugar with Na+. Kinetic analysis gave an apparent affinity constant (Kapp) of 0.20 mM and maximal rate (Jmax) of 6.87 nmol X mg protein-1 X min-1 for glucose influx in the presence of a Na gradient. In addition, a significant apparent diffusional permeability of these membranes to glucose (1.41 microliters X mg protein-1 X min-1) was observed. L-Alanine uptake in eel BBMV was shown to occur via 1) saturable Na-dependent pathway (Kapp = 1.29 mM, Jmax = 3.61 nmol X mg protein-1 X min-1), 2) a saturable Na-independent pathway (Kapp = 0.59, Jmax = 1.49), and 3) a nonsaturable component representing apparent diffusion (permeability coefficient P = 0.57 microliter X mg protein-1 X min-1). These findings suggest that similar transport systems for glucose and alanine are found in the fish and mammalian intestinal brush border membrane
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