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Many plant antioxidants, intaken through the daily diet or plant-derived dietary supplements, have been shown able to prevent free radical-related diseases by counteracting cell oxidative stress. However, it is now considered that the in vivo beneficial effects of these phytochemicals are unlikely to be explained just by their antioxidant capability. Several plant antioxidants exhibit hormetic properties, by acting as ‘low-dose stressors’ that may prepare cells to resist more severe stress. In fact, low doses of these phytochemicals activate cell signaling pathways (being the most prominent examples the modulation of the Nrf2/Keap1 pathway, the NF-B pathway and the Sirtuin-FOXO pathway) but high doses are cytotoxic. Herein we review the adaptive responses induced by the most known plant hormetic antioxidants, which are sulforaphane, resveratrol, curcumin, flavonoids, green tea catechins and diallylsulphides, as well as the molecular mechanisms involved in such responses. Furthermore, this review outlines that the hormetic properties of these bioactive plant antioxidants might be successfully employed for realizing health-promoting dietary interventions especially in the field of neurodegenerative diseases and cancer.

The present study was aimed at evaluating the in vitro antioxidant activity and in vivo photoprotective activity of an extract of wine obtained from Jacquez (Vitis aestivalis-cinerea × V vinifera) grapes (JW-E). The chemical profile of the JW-E was characterised by a significant level of proanthocyanidins, together with lower amounts of anthocyanins and hydroxycinnamic acids. The antioxidant activity of the JW-E was assessed by means of various in vitro tests (bleaching of the stable 1,1-diphenyl-2-picrylhydrazyl radical; peroxidation, induced by the water-soluble radical initiator 2,2′-azobis(2-amidinopropane) hydrochloride, on mixed dipalmitoylphosphatidylcholine/linoleic acid unilamellar vesicles; UV radiation-induced peroxidation in phosphatidylcholine multilamellar vesicles). In all in vitro tests employed, the JW-E proved to possess strong antioxidant/free radical-scavenging effectiveness. Furthermore, when topically applied, a gel formulation containing the JW-E afforded significant in vivo protection against UVB light-induced skin erythema (monitored by reflectance spectrophotometry) in healthy human volunteers.
© 2002 Society of Chemical Industry

We report that the heterotrimeric transcription factor NFY or "CAAT-binding factor" binds the -60 region of the human H ferritin promoter, the B site. DNA binding analysis with specific antibodies demonstrates that NFY/B/C subunits tightly bind this site and that NFY/C subunit is masked in vivo by binding with other protein(s). NFY binds the co-activator p300. Specifically, the NFY/B subunit interacts with the central segment of p300 in vivo and in vitro. cAMP substantially increases the formation of the NFY.p300 complex. Taken together these data provide a general model of cAMP induction of non-CRE-containing promoters and suggest that the NFY-B.p300 complex is located at the 5' end of the promoter and the NFY-B.C. TFIIB on the 3' end toward the transcription start site.

A human cDNA library was constructed using M13 derivative vectors. The simple and rapid procedures for sequencing single‐stranded DNA by the dideoxy chain termination method allowed a screening of individual clones directly by DNA sequence analysis. Some of these clones were identified as coding for: serum albumin, alpha1‐antitrypsin, retinol‐binding protein, prothrombin, haptoglobin, and metallothionein. Furthermore, a clone coding for aldolase B was tentatively identified on the basis of high sequence homology with rabbit muscle aldolase.

The transcription of the human H ferritin gene is regulated by a transcription factor, called Bbf, which binds an enhancer element located in the −100/+1 region of the H promoter. To evaluate a possible role of Bbf phopshorylation on the promoter efficiency, we exposed HeLa cells to the phosphatase inhibitor okadaic acid (OA). The okadaic acid treatment increased about 4-fold the transcription driven by the −100/+1 region of the H promoter. However, the DNA binding activity of Bbf was not modified by OA, as assessed by EMSA. Immunoprecipitation experiments demonstrated that the OA-treatment stimulates and/or stabilizes the complex between Bbf and the nuclear protein p300, most probably by inducing the phosphorylation state of the complex. Bbf depends on the p300 molecule to trigger RNA polymerase II and thus transcription of the H ferritin gene.

In this paper, we examine the mechanisms that regulate the expression of the heavy (H) ferritin subunit in the colon carcinoma Caco-2 cell line allowed to differentiate spontaneously in vitro. The differentiation process of these cells in continuous culture is accompanied by an accumulation of the mRNA coding for the apoferritin H chain. The analysis of Caco-2 subclones stably transfected with an H-chain promoter-chloramphenicol acetyltransferase (CAT) construct revealed that the mRNA increase is paralleled by an enhanced transcription of the H gene, driven by the -100 to +4 region of the H promoter. The H gene transcriptional activation seems to be a specific feature of differentiated Caco-2 cells, since the activity of other promoters did not change upon differentiation. The -100 to +4 region of the H promoter binds a transcription factor called Bbf (B-box binding factor); electrophoretic-mobility-shift-assay analyses showed that the retarded complex due to Bbf-H promoter interaction is significantly increased in the differentiated cells. We propose that the activation of H-ferritin gene expression may be associated with the establishment of a differentiated phenotype in Caco-2 cells, and that the H-ferritin gene transcriptional up-regulation is accompanied by a modification in the activity of the transcription factor Bbf.

A human cDNA library was constructed using M13 derivative vectors. The simple and rapid procedures for sequencing single‐stranded DNA by the dideoxy chain termination method allowed a screening of individual clones directly by DNA sequence analysis. Some of these clones were identified as coding for: serum albumin, alpha1‐antitrypsin, retinol‐binding protein, prothrombin, haptoglobin, and metallothionein. Furthermore, a clone coding for aldolase B was tentatively identified on the basis of high sequence homology with rabbit muscle aldolase.

Incubating human cells in diethylmaleate (DEM) depletes the intracellular pool of reduced glutathione (GSH) and increases the concentration of oxidative free radicals. We found that DEM-induced oxidative stress reduced the ability of p53 to bind its consensus recognition sequence and to activate transcription of a p53-specific reporter gene. Nevertheless, DEM treatment induced expression of WAF1/CIP1 but not GADD45 mRNA. The fact that N-acetylcysteine, a precursor of GSH that blocks oxidative stress, prevented WAF1/CIP1 induction by DEM suggests that WAF1/CIP1 induction probably was a consequence of the ability of DEM to reduce intracellular GSH levels. DEM induced WAF1/CIP1 expression in Saos-2 and T98G cells, both of which lack functional p53 protein. DEM treatment did not produce an increase in membrane-associated protein kinase C, but ERK2, a mitogen-activated protein kinase, was phosphorylated in a manner consistent with ERK2 activation. DEM treatment also produced a dose-dependent delay in cell cycle progression, which at low concentrations (0.25 mM) consisted of a G2/M arrest and at higher concentrations (1 mM) also involved G1 and S phase delays. Our results indicate that oxidative stress induces WAF1/CIP1 expression and arrests cell cycle progression through a mechanism that is independent of p53. This mechanism may provide for cell cycle checkpoint control under conditions that inactivate p53.

In the present study we evaluated the occupational exposure to N2O and isoflurane during open circuit (OC) (fresh gas flow ≥ minute volume) and low flow (LF) (fresh gas flow=1.5 1/min) anaesthesia. The effects of active scavenging and of a charcoal filter positioned on the exhausting branch of the ventilator on environmental and urinary concentrations of inhalation anaesthetics were also investigated. The study was carried out in the same operating room provided with non‐recirculating air changes (10 per hour). It involved anaesthetists and nurses during routine activity. N2O and isoflurane concentrations (time‐weighted average) were measured after 3‐hour continuous exposure: 1) in the environment at the level of the personnel's breathing zone (Ci); 2) in the environment at the ventilator zone (C); 3) in urine (Cu). During OC anaesthesia without active scavenging the breathing zone concentration of both N2O and isoflurane was very high (194.6±15.2 and 5.0±0.4 ppm, respectively). The activation of the scavenging greatly reduced the breathing zone concentration of N2O (31.6±4.1 ppm) and isoflurane (1.7±0.2 ppm). LF anaesthesia (with active scavenging) significantly reduced the environmental concentration of both anaesthetics (Ci N2O and isoflurane 22.7±1.8 and 0.6±0.04 ppm, respectively). During LF anaesthesia the breathing zone concentration of N2O remained low, even without scavenging (22.7 ±1.8 ppm). Similar results were obtained by measuring N2O and isoflurane concentrations at the ventilator zone and in urine. The application of a charcoal filter to the exhausting branch of the ventilator during LF anaesthesia without active scavenging reduced the environmental concentration of isoflurane to a lower value than that obtained with OC anaesthesia with active scavenging (Ci 0.88±0.1 vs1.7±0.2 ppm). A linear correlation was found between environmental (Ci) and urinary concentrations of N2O and isoflurane. Our data show that LF anaesthesia reduces the exposure of the operating room personnel to inhalation anaesthetics. A charcoal filter positioned on the exhausting branch of the ventilator in substitution of the active scavenging is very effective in reducing isoflurane pollution. The evaluation of the urinary concentration of inhalation anaesthetics is a simple and reliable method of monitoring occupationally exposed personnel.

We have investigated the effect of redox changes in vivo on the differentiation of two human myeloid cell lines, HL-60 and KG-1. The glutathione-depleting agent diethyl maleate (DEM) prevented the development of differentiated features in response to phorbol esters, including adherence of the cells to plastic surfaces and repression of the myeloperoxidase and CD34 genes. Moreover, DEM abolished phorbol 12-myristate 13-acetate-induced activation of the transcription factors AP-1 and Egr-1, suggesting that inhibition of differentiation may be due, at least in part, to redox modifications of these proteins.

Transcription of the H ferritin gene in vivo is stimulated by cAMP and repressed by the E1A oncoprotein. We report here the identification of the cis-element in the human promoter responsive to both cAMP- and E1A-mediated signals. This promoter region is included between positions -62 to -45 and binds a approximate 120-kDa transcription factor called Bbf. Bbf forms a complex in vivo with the coactivator molecules p300 and CBP. Recombinant E1A protein reduces the formation of these complexes. In vivo overexpression of p300 in HeLa cells reverses the E1A-mediated inhibition of the ferritin promoter transcription driven by Bbf. These data suggest the existence of a common mechanism for the cAMP activation and the E1A-mediated repression of H ferritin transcription.

We isolated the gene encoding the brain specific snRNPassociated polypeptide "N" from a rat genomic library. Some intronless genes have previously been reported for this polypeptide in the rat. In contrast, our gene consists of at least nine exons (the last exon(s) encoding the 3′-end of the mRNA has not been isolated). The second intron of the gene is probably so long as to hamper the cloning of the complete gene into a single phage vector. Therefore, we used polymerase chain reaction amplification of the rat genome with oligonucleotides designed on the basis of known cDNA sequences that allowed us to isolate and clone the first two exons at the 5′-end of the gene. Primer extension studies revealed multiple transcription start sites, all of them contained within the first exon. The intron/exon organization coincides with the alternative splicing events suggested by the sequences of the various cDNA species isolated so far. As also reported by others, genomic Southern analysis suggests the presence of other genomic regions containing sequences strongly hybridizing to the cDNA. We isolated and characterized two of these regions. They contain sequences very similar to the cDNA, not interrupted by introns and flanked by a polyA tail at their 3′-ends; hence they are considered two different pseudogenes.

We have characterized the promoter of the human gene coding for the apoferritin L subunit. Transient transfections of 5' and 3' deletion mutants indicate that the efficiency of the L promoter depends on both negative and positive cis-elements, located upstream and downstream of the transcription start point. DNaseI footprinting analysis of this DNA region revealed the presence of five protected segments. The most upstream one (element 1) corresponds to the negative cis-element and is recognized by factor(s) sharing a GC-sequence specificity. Three positive elements are in the region upstream of the start of transcription; a fifth positive cis-element (element 5) is localized in the first exon of the L gene.Copyright 1995, 1999 Academic Press, Inc.

Summary. Familial chronic nail candidiasis (FCNC.MIM 607644) is a rare disorder characterized by early onset infections caused by different species of Candida and restricted to the nails; this disorder is genetically associated with low serum concentration of intercellular adhesion molecule 1 (ICAM-1). Herein we report the evidence of high circulating levels of malondialdehyde (MDA) and 4-hydroxy-2,3-nonenal (HNE) in seven patients of a five-generation Italian family affected by FCNC.MIM 607644. The present data evidence, in these patients, an increase in circulating MDA and HNE levels. Only some merely speculative hypotheses may be suggested to explain the mechanisms subserving the oxidative stress condition observed in these genetically ICAM-1 deficient patients; however, one has to point out that a chronic oxidative stress condition could contribute to the development of concurrent pathological alterations in which an overproduction of free radicals may play a central role.

Purified tRNA genes are expressed when microinjected into the nucleus of X.laevis oocytes. In this paper we describe a method to assay the capacity to be aminoacylated of the tRNA transcribed in the frog oocytes. The method exploits the radiochemical purity of the transcript and relies on the binding of aminoacyl-tRNA but not of uncharged tRNA to purified elongation factor EF-TU. We also present some preliminary results on several single point mutants of tRNAPro from Caenorhabditis elegans. We show that nucleotide 73 of tRNAPro can be substituted by any other nucleotide without loss of acceptor activity. A doublemutant, causing transition from G45G46 to A4546 has lost acceptor activity. Also inactive is a mutant carrying an insertion of a single base in the anticodon loop.