Metallothionein expression in the central nervous system in response to chronic heavy metal exposure: possible neuroprotective mechanism

It has been reported that volcanoes release several tonnes of mercury per year among other heavy metals through eruptions, fumaroles, or diffuse soil degassing. Since a high percentage of the world's population lives in the vicinity of an active volcano, the aim of this study is to evaluate the accumulation of these metals in the central nervous system and the presence of cellular mechanisms of heavy metal detoxification such as metallothioneins. To carry out this study, wild mice (Mus musculus) chronically exposed to an active volcanic environment were captured in Furnas village (Azores, Portugal) and compared with those trapped in a reference area (Rabo de Peixe, Azores, Portugal). On the one hand, the heavy metal load has been evaluated by analyzing brain and cerebellum using ICP-MS and a mercury analyzer and on the other hand, the presence of metallothionein 2A has been studied by immunofluorescence assays. Our results show a higher load of metals such as mercury, cadmium and lead in the central nervous system of exposed mice compared to non-exposed individuals and, in addition, a higher immunoreactivity for metallothionein 2A in different areas of the cerebrum and cerebellum indicating a possible neuroprotection process.

Integral valorisation of tomato by-products towards bioactive compounds recovery: Human health benefits

The tomato processing industry is one of the world's most important markets. This industry aims to optimise production, minimise energy costs and waste streams while ensuring high-quality products. This sector produces substantial amounts of by-products frequently disposed of as waste rather than reintroducing them with a new intent into the supply chain. However, these by-products are rich in bioactive compounds (BC), including carotenoids, fibre, which exhibit antioxidant, anti-inflammatory and chemopreventive properties, and cardiovascular protection. Reusing these compounds is favourable to reducing the environmental impact and enables the development of added-value products with various possible uses such as food and feed additives, nutraceuticals, cosmeceuticals, etc. This review summarises relevant issues towards the recovery and valorisation of BC from industrial tomato by-products within a circular economy context.

The Complex Dynamic of Phase I Drug Metabolism in the Early Stages of Doxorubicin Resistance in Breast Cancer Cells

The altered activity of drug metabolism enzymes (DMEs) is a hallmark of chemotherapy resistance. Cytochrome P450s (CYPs), mainly CYP3A4, and several oxidoreductases are responsible for Phase I metabolism of doxorubicin (DOX), an anthracycline widely used in breast cancer (BC) treatment. This study aimed to investigate the role of Phase I DMEs involved in the first stages of acquisition of DOX-resistance in BC cells. For this purpose, the expression of 92 DME genes and specific CYP-complex enzymes activities were assessed in either sensitive (MCF-7 parental cells; MCF-7/DOX^S) or DOX-resistant (MCF-7/DOX^R) cells. The DMEs genes detected to be significantly differentially expressed in MCF-7/DOX^R cells (12 CYPs and eight oxidoreductases) were indicated previously to be involved in tumor progression and/or chemotherapy response. The analysis of CYP-mediated activities suggests a putative enhanced CYP3A4-dependent metabolism in MCF-7/DOX^R cells. A discrepancy was observed between CYP-enzyme activities and their corresponding levels of mRNA transcripts. This is indicative that the phenotype of DMEs is not linearly correlated with transcription induction responses, confirming the multifactorial complexity of this mechanism. Our results pinpoint the potential role of specific CYPs and oxidoreductases involved in the metabolism of drugs, retinoic and arachidonic acids, in the mechanisms of chemo-resistance to DOX and carcinogenesis of BC.

Epithelial morphometric alterations and mucosecretory responses in the nasal cavity of mice chronically exposed to hydrothermal emissions

Air pollutants (either of natural or anthropogenic origin) represent a considerable environmental risk to human health by affecting the respiratory system and causing respiratory disorders. In this study, we investigate the effects of chronic exposure to hydrothermal emissions on the nasal cavity of mice since it is the first and the most exposed region of the respiratory system. This study, carried in S. Miguel Island, Azores-Portugal, used Mus musculus as a bioindicator species. Mice were captured in an area with non-eruptive active volcanism (Furnas Village) and another area without volcanism (Rabo de Peixe, reference site). The hydrothermal emissions present at Furnas Village are characterized by the continuous release of several gases (CO₂, H₂S, ²²²Rn) along with metals (e.g. Hg, Cd, Zn, Al) and particulate matter into the environment. We test the hypothesis whether chronic exposure to this specific type of pollution causes epithelial morphometric, mucosecretory and neuronal alterations on the nasal cavity. Thickness measurements were taken in the squamous, respiratory and olfactory epithelia. The relative density of cell types (basal, support and neurons) was also assessed in the olfactory epithelium and the mucosecretory activity was determined in the lateral nasal glands, Bowman's gland and goblet cells. Mice chronically exposed to hydrothermal emissions presented thinner olfactory epithelia and lesser mucous production, which could result in loss of olfactory capabilities as well as a decrease in the protective function provided by the mucous to the lower respiratory tract. For the first time, it is demonstrated that, in mice, this specific type of non-eruptive active volcanism causes epithelial and mucosecretory alterations, leading to the loss of olfactory capabilities.

Treatment of fruit processing wastewater by electrochemical and activated persulfate processes: Toxicological and energetic evaluation

A fruit processing wastewater was submitted to different advanced oxidation processes, namely, electro-Fenton (EF), electrochemical oxidation (EO), activated persulfate (PS), and combined EF/PS. The performance of the treatment processes, at different experimental conditions, regarding organic load removal, biodegradability increment, toxicity reduction, and specific energy consumption (E_sp), was evaluated. At the experimental conditions studied, EO led to the treated solutions with the highest biodegradability increment, from 0.24 to 0.48, and toxicity reduction towards Daphnia magna, from 5.8 to 1.5 toxic units, without requiring the addition of chemicals. Nevertheless, the highest chemical oxygen demand (COD) removals were obtained for EF and combined EF/PS treatments. For the electrochemical processes, an increase in COD removal rate with applied current density (j) was observed. However, the increase in j substantially raised the E_sp. In PS treatment, COD removals above 80% were only achieved for high amounts of added persulfate and iron, which led to less biodegradable and more toxic solutions. Combined EF/PS attained the lowest E_sp values, mainly due to the conductivity increase originated by the persulfate and iron salts addition. Besides the disadvantage of the chemicals added, this combined treatment led to treated solutions with very acidic pH and significant iron content.

Occurrence of Volcanogenic Inorganic Mercury in Wild Mice Spinal Cord: Potential Health Implications

Mercury accumulation has been proposed as a toxic factor that causes neurodegenerative diseases. However, the hazardous health effects of gaseous elemental mercury exposure on the spinal cord in volcanic areas have not been reported previously in the literature. To evaluate the presence of volcanogenic inorganic mercury in the spinal cord, a study was carried out in São Miguel island (Azores, Portugal) by comparing the spinal cord of mice exposed chronically to an active volcanic environment (Furnas village) with individuals not exposed (Rabo de Peixe village), through the autometallographic silver enhancement histochemical method. Moreover, a morphometric and quantification analysis of the axons was carried out. Results exhibited mercury deposits at the lumbar level of the spinal cord in the specimens captured at the site with volcanic activity (Furnas village). A decrease in axon calibre and axonal atrophy was also observed in these specimens. Given that these are relevant hallmarks in the neurodegenerative pathologies, our results highlight the importance of the surveillance of the health of populations chronically exposed to active volcanic environments.

Chronic exposure to volcanic gaseous elemental mercury: using wild Mus musculus to unveil its uptake and fate

Volcanoes are a natural source of gaseous elemental mercury (GEM) (Hg⁰). Monitoring GEM releases of volcanic origin has been widely studied; however, few studies have been performed about the biomonitoring of species exposed to GEM, rendering an unknown risk to the worldwide populations living in the vicinity of an active volcano. In this pilot study, we used Mus musculus as a bioindicator species to understand to what extent lungs are the main route of mercury uptake in populations chronically exposed to active volcanic environments. Autometallographic silver protocol was used to detect mercury deposits in the histological lung slides. Abundant mercury deposits were found in the lungs of specimens captured at the site with volcanic activity (Furnas Village, S. Miguel Island-Azores). The presence of mercury in the lungs could represent not only hazardous effects to the lung itself but also to other tissues and organs, such as brain and kidneys. This study confirms that the main uptake route for GEM is the lungs and that, even at very low concentrations in the environment, a chronic exposure to Hg⁰ results in its bioaccumulation in the lung tissue. These results reinforce that biomonitoring studies should be combined with monitoring classical approaches in order to better characterize the risks of exposure to Hg⁰ in volcanic environments.

First report on the prevalence of Klossiella muris in Mus musculus for S. Miguel Island - Azores (Portugal)

Klossiella is a genus of apicomplexan coccidian parasites with a global distribution, whose members typically infect the renal tissue of a wide variety of vertebrate hosts with a high level of host specificity. The presence of this parasite has been previously associated with kidney inflammatory processes. To our knowledge, this is the first report on the prevalence of Klossiella muris in the house mouse (Mus musculus) in Portugal (São Miguel Island - Azores). The prevalence of K. muris was determined through histopathological examination of renal tissue collected during necropsy of 130 mice captured between the years of 2011-2019. K. muris was diagnosed in 45.38% (CI₉₅: 40.9-85.4) of the examined mice. Infection with this parasite was associated with mild to severe kidney inflammation, assessed by the presence of inflammatory processes in the renal cortex and medulla. CAPSULE: First record on coccidiosis caused by infection of Klossiella muris in Mus musculus in Portugal.

Reactive astrogliosis in the dentate gyrus of mice exposed to active volcanic environments

Air pollution has been associated with neuroinflammatory processes and is considered a risk factor for the development of neurodegenerative diseases. Volcanic environments are considered a natural source of air pollution. However, the effects of natural source air pollution on the central nervous system (CNS) have not been reported, despite the fact that up to 10% of the world's population lives near a historically active volcano. In order to assess the response of the CNS to such exposure, our study was conducted in the island of Sao Miguel (Azores, Portugal) in two different areas: Furnas, which is volcanically active one, and compared to Rabo de Peixe, a reference site without manifestations of active volcanism using Mus musculus as a bioindicator species. To evaluate the state of the astroglial population in the dentate gyrus in both samples, the number of astrocytes was determined using immunofluorescence methods (anti-GFAP and anti-GS). In addition, the astrocytic branches in that hippocampal area were examined. Our results showed an increase in GFAP+ astrocytes and a reduction in GS+ astrocytes in Furnas-exposed mice compared to animals from Rabo de Peixe. In addition, astrocytes in the dentate gyrus of chronically exposed animals exhibited longer branches compared to those residing at the reference site. Thus, reactive astrogliosis and astrocyte dysfunction are found in mice living in an active volcanic environment.

First record on mercury accumulation in mice brain living in active volcanic environments: a cytochemical approach

The health effects of mercury vapor exposure on the brain in volcanic areas have not been previously addressed in the literature. However, 10% of the worldwide population inhabits in the vicinity of an active volcano, which are natural sources of elemental mercury emission. To evaluate the presence of mercury compounds in the brain after chronic exposure to volcanogenic mercury vapor, a histochemical study, using autometallographic silver, was carried out to compare the brain of mice chronically exposed to an active volcanic environment (Furnas village, Azores, Portugal) with those not exposed (Rabo de Peixe village, Azores, Portugal). Results demonstrated several mercury deposits in blood vessels, white matter and some cells of the hippocampus in the brain of chronically exposed mice. Our results highlight that chronic exposure to an active volcanic environment results in brain mercury accumulation, raising an alert regarding potential human health risks. These findings support the hypothesis that mercury exposure can be a risk factor in causing neurodegenerative diseases in the inhabitants of volcanically active areas.

ABC Efflux Transporters and the Circuitry of miRNAs: Kinetics of Expression in Cancer Drug Resistance

Cancer drug resistance (CDR) is a major problem in therapeutic failure. Over 90% of patients with metastatic cancer present CDR. Several mechanisms underlie CDR, including the increased expression of efflux ABC transporters and epigenetic phenomena. Nevertheless, a topic that is not usually addressed is the mechanism underlying the loss of CDR once the challenge to these cells is withdrawn. A KCR cell line (doxorubicin-resistant, expressing ABCB1) was used to induce loss of resistance by withdrawing doxorubicin in culture medium. ABCB1 activity was analysed by fluorescence microscopy and flow cytometry through substrate (DiOC2) retention assays. The expression of 1008 microRNAs was assessed before and after doxorubicin withdrawal. After 16 weeks of doxorubicin withdrawal, a decrease of ABCB1 activity and expression occurred. Moreover, we determined a signature of 23 microRNAs, 13 underexpressed and 10 overexpressed, as a tool to assess loss of resistance. Through pathway enrichment analysis, "Pathways in cancer", "Proteoglycans in cancer" and "ECM-receptor interaction" were identified as relevant in the loss of CDR. Taken together, the data reinforce the assumption that ABCB1 plays a major role in the kinetics of CDR, and their levels of expression are in the dependence of the circuitry of cell miRNAs.

Chronic exposure to non-eruptive volcanic activity as cause of bronchiolar histomorphological alteration and inflammation in mice

It is estimated that 10% of the worldwide population lives in the vicinity of an active volcano. However, volcanogenic air pollution studies are still outnumbered when compared with anthropogenic air pollution studies, representing an unknown risk to human populations inhabiting volcanic areas worldwide. This study was carried out in the Azorean archipelago of Portugal, in areas with active non-eruptive volcanism. The hydrothermal emissions within the volcanic complex of Furnas (São Miguel Island) are responsible for the emission of nearly 1000 tons of CO₂ per day, along with H₂S, the radioactive gas - radon, among others. Besides the gaseous emissions, metals (e.g., Hg, Cd, Al, Ni) and particulate matter are also released into the environment. We test the hypothesis that chronic exposure to volcanogenic air pollution alters the histomorphology of the bronchioles and terminal bronchioles, using the house mouse, Mus musculus, as bioindicator species. Mus musculus were live-captured at three different locations: two villages with active volcanism and a village without any type of volcanic activity (reference site). The histomorphology of the bronchioles (diameter, epithelium thickness, smooth muscle layer thickness, submucosa thickness and the histological evaluation of the peribronchiolar inflammation) and of the terminal bronchioles (epithelium thickness and classification) were evaluated. Mice chronically exposed to volcanogenic air pollution presented bronchioles with increased epithelial thickness, increased smooth muscle layer, increased submucosa thickness and increased peribronchiolar inflammation. Similarly, terminal bronchioles presented structural alterations consistent with bronchodysplasia. For the first time we demonstrate that chronic exposure to non-eruptive volcanically active environments causes inflammation and histomorphological alterations in mice lower airways consistent with asthma and chronic bronchitis. These results reveal that chronic exposure to non-eruptive volcanic activity represents a risk factor that can affect the health of the respiratory system of humans inhabiting hydrothermal areas.

A personally guided tour on some of our data with the Ames assay-A tribute to Professor Bruce Ames

In contributing to this Special Issue of Mutation Research dedicated to Professor Bruce N. Ames in recognition of his 90^th birthday in December 2018, we intend to portray the importance not only of the Ames Salmonella/mammalian-microsome mutagenicity assay in some of our studies over the years, but also the importance of the insight that Bruce Ames brought to the field of genetic toxicology.

Overproduction of TNF-α and lung structural remodelling due to chronic exposure to volcanogenic air pollution

Volcanogenic air pollution studies and their effects on the respiratory system are still outnumbered by studies regarding the effects of anthropogenic air pollution, representing an unknown risk to human population inhabiting volcanic areas worldwide (either eruptive or non-eruptive areas). This study was carried in the archipelago of the Azores- Portugal, in two areas with active volcanism (Village of Furnas and Village of Ribeira Quente) and a reference site (Rabo de Peixe). The hydrothermal volcanism of Furnas volcanic complex is responsible for the release of 1000 t d^-1 of CO₂, H₂S, the radioactive gas - radon, among others. Besides the gaseous emissions, particulate matter and metals (Hg, Cd, Zn, Al, Ni, etc.) are also released into the environment. We tested a hypothesis whether chronic exposure to volcanogenic air pollution causes lung structural remodelling, in the house mouse, Mus musculus, as a bioindicator species. Histopathological evaluations were performed to assess the amount of macrophages, mononuclear leukocyte infiltrate, pulmonary emphysema, and the production of pro-inflammatory cytokine TNF-α. Also, the percentage of collagen and elastin fibers was calculated. Mice chronically exposed to volcanogenic air pollution presented an increased score in the histopathological evaluations for the amount of macrophages, mononuclear leukocyte infiltrate, pulmonary emphysema and production of TNF-α; and also increased percentages of collagen and elastin. For the first time, we demonstrate that non-eruptive active volcanism has a high potential to cause lung structural remodelling. This study also highlights the Mus musculus as a useful bioindicator for future biomonitoring programs in these type of volcanic environments.

N-break states in a chain of nonlinear oscillators

In the present work we explore a prestretched oscillator chain where the nodes interact via a pairwise Lennard-Jones potential. In addition to a homogeneous solution, we identify solutions with one or more (so-called) "breaks," i.e., jumps. As a function of the canonical parameter of the system, namely, the precompression strain d, we find that the most fundamental one-break solution changes stability when the monotonicity of the Hamiltonian changes with d. We provide a proof for this (motivated by numerical computations) observation. This critical point separates stable and unstable segments of the one-break branch of solutions. We find similar branches for two- through five-break branches of solutions. Each of these higher "excited state" solutions possesses an additional unstable pair of eigenvalues. We thus conjecture that k-break solutions will possess at least k-1 (and at most k) pairs of unstable eigenvalues. Our stability analysis is corroborated by direct numerical computations of the evolutionary dynamics.

Hydrodynamics and two-dimensional dark lump solitons for polariton superfluids

We study a two-dimensional incoherently pumped exciton-polariton condensate described by an open-dissipative Gross-Pitaevskii equation for the polariton dynamics coupled to a rate equation for the exciton density. Adopting a hydrodynamic approach, we use multiscale expansion methods to derive several models appearing in the context of shallow water waves with viscosity. In particular, we derive a Boussinesq/Benney-Luke-type equation and its far-field expansion in terms of Kadomtsev-Petviashvili-I (KP-I) equations for right- and left-going waves. From the KP-I model, we predict the existence of vorticity-free, weakly (algebraically) localized two-dimensional dark-lump solitons. We find that, in the presence of dissipation, dark lumps exhibit a lifetime three times larger than that of planar dark solitons. Direct numerical simulations show that dark lumps do exist, and their dissipative dynamics is well captured by our analytical approximation. It is also shown that lumplike and vortexlike structures can spontaneously be formed as a result of the transverse "snaking" instability of dark soliton stripes.

Electrodegradation of naphthalenic amines: Influence of the relative position of the substituent groups, anode material and electrolyte on the degradation products and kinetics

The electrodegradation of the 4-aminonaphthalene-1-sulfonic acid (4AN1S), 5-aminonaphthalene-2-sulfonic acid (5AN2S) and 8-aminonaphthalene-2-sulfonic acid (8AN2S) was studied, using two electrode materials as anode, BDD and Ti/Pt/PbO₂, and two different electrolytes, sodium sulfate and sodium chloride. The highest COD removal rates were obtained at BDD: for 5AN2S and 8AN2S results were similar in both electrolytes; for 4AN1S, results were better in sodium chloride. The lowest COD removal rates were obtained at the system Ti/Pt/PbO₂-sodium sulfate, for all the studied amines. The dissolved organic carbon (DOC) removal was much higher at BDD for all the amines, in sulfate for 5AN2S and 8AN2S and in chloride for 4AN1S. Nitrogen removal was always almost irrelevant in sulfate medium but higher than 60%, after 6-h assays, in chloride. The highest combustion efficiencies were attained at the system BDD-sodium sulfate and were: 4AN1S-75%; 5AN2S-84%; 8AN2S-74%. HPLC results show that total degradation of the studied aminonaphthalene sulfonates is attained at both anode materials, utilizing any of the electrolytes, with a first order kinetics. However, kinetic constants obtained with the variation of the amines concentration in time are 10-40 times higher in chloride, being slightly higher at Ti/Pt/PbO₂ than at BDD. Regarding the presence of carboxylic acids during the degradation assays, it was observed that the electrolysis of the amines 5AN2S and 8AN2S always lead to higher amounts of oxalic acid and lower quantities of acetic acid than the electrolysis of the amine 4AN1S.

Long-Term Peritoneal Dialysis Experience in Portugal

Peritoneal dialysis (PD) penetration varies widely. Since the beginning of this therapy, indications have changed and outcomes have improved. In Portugal, PD still remains clearly underutilized.

The results of a 20 year PD programme were evaluated: 312 cumulative patients, 48±16 years, 27% >60 years old, 27% diabetic, 59% with prior hemodialysis (HD). The main reason for admission was vascular access failure (48.7%). Admission due to patient preference has increased significantly between first and second decades of the programme (33% vs 47% (P<0.001)); 98 patients (31.4%) were treated with automated PD but this prescription increased to 43% of the active patients.

A total of 376 Tenckhoff catheters were surgically implanted, recently by the Popovich-Moncrief technique (77 catheters): the cumulative survival was 82%, 64% and 50% at 1, 3 and 5 years, respectively. A better catheter survival was found in the last decade (85.7%, 69.6%, 54.8% versus 77.3%, 55.5%, 40.2%, at 1, 3 and 5 years, respectively (P=0.007).

The patient and technique cumulative survivals were 91, 74, 55% and 85, 67, 41%, at 1, 3, and 5 years, respectively.

The main drop-out was to hemodialysis (35.8%), followed by death (23.7%), and transplantation (21.5%). Peritonitis and access-related infections caused 35% of the transfer to HD. Cardiovascular events caused 58% of deaths. The median PD retention was 35.5 months. The rate of peritonitis has decreased to one episode /30 patient months. Hospital admission has also decreased to 4.8 days/patient year.

This is a first report on long-term PD experience in Portugal. It has been an effective modality of renal replacement therapy, reflected by the growing patient preference in our PD programme. Experience, knowledge and new technical solutions have improved the outcomes.

Down syndrome and microRNAs

In recent years numerous studies have indicated the importance of microRNAs (miRNA/miRs) in human pathology. Down syndrome (DS) is the most prevalent survivable chromosomal disorder and is attributed to trisomy 21 and the subsequent alteration of the dosage of genes located on this chromosome. A number of miRNAs are overexpressed in down syndrome, including miR-155, miR-802, miR- 125b-2, let-7c and miR-99a. This overexpression may contribute to the neuropathology, congenital heart defects, leukemia and low rate of solid tumor development observed in patients with DS. MiRNAs located on other chromosomes and with associated target genes on or off chromosome 21 may also be involved in the DS phenotype. In the present review, an overview of miRNAs and the haploinsufficiency and protein translation of specific miRNA targets in DS are discussed. This aimed to aid understanding of the pathogenesis of DS, and may contribute to the development of novel strategies for the prevention and treatment of the pathologies of DS.

Hybrid mesoporous silica nanocarriers with thermovalve-regulated controlled release

Mesoporous silica nanoparticles (MSNs) are excellent nanocarriers, featuring very high cargo capacity due to their large surface area and pore volume. The particle and pore dimensions can be accurately tuned, and both the internal and external surfaces allow versatile functionalization. We developed hybrid MSNs with diameters around 140 nm, with the external surface selectively modified with a temperature-responsive biocompatible copolymer to control cargo release. The nanoparticles feature either a polymer brush or a gel-like responsive shell, produced by grafting from RAFT polymerization of PEG-acrylate macromonomers. The hybrid nanoparticles have fluorescent molecules incorporated into the inorganic network providing excellent optical properties for traceability and imaging. The cargo release profiles are explained by a temperature-controlled "pumping" mechanism: at low temperature (ca. 20 °C) the polymer shell is hydrophilic and expanded, opposing cargo diffusion out of the shell and retaining the molecules released from the mesopores; above room temperature (ca. 40-50 °C) the polymer network becomes more hydrophobic and collapses onto the silica surface, releasing the cargo by a sponge-like squeezing effect. The release kinetics depends on the polymer shell type, with better results obtained for the gel-coated nanoparticles. Our proof-of-concept system shows that by modulating the temperature, it is possible to achieve a pumping regime that increases the release rate in a controlled way.

In vitro and in vivo biological characterization of the anti-proliferative potential of a cyclic trinuclear organotin(iv) complex

Identification of novel molecules that can selectively inhibit the growth of tumor cells, avoid causing side effects to patients and/or intrinsic or acquired resistance, usually associated with common chemotherapeutic agents, is of utmost importance. Organometallic compounds have gained importance in oncologic chemotherapy, such as organotin(iv) complexes. In this study, we assessed the anti-tumor activity of the cyclic trinuclear organotin(iv) complex with an aromatic oximehydroxamic acid group [nBu2Sn(L)]3(H2L = N,2-dihydroxy-5-[N-hydroxyethanimidoyl]benzamide) - MG85 - and provided further characterization of its biological targets. We have previously shown the high anti-proliferative activity of this complex against human colorectal and hepatocellular carcinoma cell lines and lower cytotoxicity in neonatal non-tumor fibroblasts. MG85 induces tumor cell apoptosis and down-regulation of proteins related to tubulin dynamics (TCTP and COF1). Further characterization included the: (i) evaluation of interference in the cell cycle progression, including the expression of critical genes; (ii) affinity to DNA and the corresponding mode of binding; (iii) genotoxic potential in cells with deficient DNA repair pathways; and (iv) in vivo tumor reduction efficiency using mouse colorectal carcinoma xenografts.

Assessing microbial activities in metal contaminated agricultural volcanic soils--An integrative approach

Volcanic soils are unique naturally fertile resources, extensively used for agricultural purposes and with particular physicochemical properties that may result in accumulation of toxic substances, such as trace metals. Trace metal contaminated soils have significant effects on soil microbial activities and hence on soil quality. The aim of this study is to determine the soil microbial responses to metal contamination in volcanic soils under different agricultural land use practices (conventional, traditional and organic), based on a three-tier approach: Tier 1 - assess soil microbial activities, Tier 2 - link the microbial activity to soil trace metal contamination and, Tier 3 - integrate the microbial activity in an effect-based soil index (Integrative Biological Response) to score soil health status in metal contaminated agricultural soils. Our results showed that microbial biomass C levels and soil enzymes activities were decreased in all agricultural soils. Dehydrogenase and β-glucosidase activities, soil basal respiration and microbial biomass C were the most sensitive responses to trace metal soil contamination. The Integrative Biological Response value indicated that soil health was ranked as: organic>traditional>conventional, highlighting the importance of integrative biomarker-based strategies for the development of the trace metal "footprint" in Andosols.

Bean Type Modifies Larval Competition in Zabrotes subfasciatus (Chrysomelidae: Bruchinae)

Larval competition is particularly prevalent among grain beetles that remain within their mother-selected grain throughout development, and the behavioral process of competition is usually inferred by the competition outcome. The Mexican bean weevil Zabrotes subfasciatus (Boheman) is subjected to resource availability variation because of the diversity of common bean types and sizes, from small (e.g., kidney beans) to large (e.g., cranberry beans). The competition process was identified in the Mexican bean weevil reared on kidney and cranberry beans by inference from the competition outcome and by direct observation through digital X-ray imaging. Increased larval density negatively affected adult emergence in kidney beans and reduced adult body mass in both kidney and cranberry beans. Developmental time was faster in cranberry beans. The results allowed for increased larval fitness (i.e., higher larval biomass produced per grain), with larval density reaching a maximum plateau >5 hatched larvae per kidney bean, whereas in cranberry beans, larval fitness linearly increased with density to 13 hatched larvae per bean. These results, together with X-ray imaging without evidence of direct aggressive interaction among larvae, indicate scramble competition, with multiple larvae emerging per grain. However, higher reproductive output was detected for adults from lower density competition with better performance on cranberry beans. Larger populations and fitter adults are expected in intermediate larval densities primarily in cranberry beans where grain losses should be greater.

Linking trace metals and agricultural land use in volcanic soils--a multivariate approach

The concern about the environmental impacts caused by agriculture intensification is growing as large amounts of nutrients and contaminants are introduced into soil ecosystems. Volcanic soils are unique naturally fertile resources extensively used for agricultural purposes, with particular physical and chemical properties that may result in possible accumulation of toxic substances, such as metals. Within this particular geological context, the present study aims to evaluate the impact of different agricultural systems (conventional, traditional and organic) in trace metal (TM) soil pollution and define the tracers for each one. Physicochemical properties and TM contents in agricultural topsoils were determined. Enrichment Factors (EF) were calculated to distinguish geogenic and anthropogenic contribution to TM contents in agricultural soils. An ensemble of multivariate statistical analyses (PCA and FDA) was performed to reduce the multidimensional space of variables and samples, thus defining a set of TM as tracers of distinct agricultural farming systems. Results show that agricultural soils have low organic matter content (<5%) compared to reference soil (>30%); in addition, electric conductivity in conventional farming soils is higher (262.3 ± 162.6 μS cm(-1)) while pH is lower (5.8 ± 0.3). Regarding metal inputs, V, Ba and Hg soil contents are mainly of geogenic origin, while Li, P, K, Cr, Mn, Ni, Cu, Zn, As, Mo, Cd and Pb result primarily from anthropogenic inputs. Li revealed to be a tracer of agricultural pollution in conventional farming soils, whereas V allowed the discrimination of traditional farming soils. This study points to agriculture as a diffuse source of anthropogenic TM soil pollution and is the first step to identify priority chemicals affecting agricultural Andosols.

Increasing the added-value of onions as a source of antioxidant flavonoids: a critical review

Flavonoids are a large and diverse group of polyphenolic compounds with antioxidant effects. While the flavonoid content and composition profile clearly reflect the genetic background of the cultivar, environmental conditions and agronomic practices are also determinants for the composition of crops at harvest. Considerable research has been directed toward understanding the nature of polyphenols in different products and the factors influencing their accumulation. This review examines the flavonoids as a class of compounds, the role these compounds play in the plant, their contributions to product quality, and recent research on the impacts of environmental factors and cultural practices on flavonoid content in onions, highlighting how this knowledge may be used to modulate their polyphenolic composition at harvest or during post-harvest handling.

From nodeless clouds and vortices to gray ring solitons and symmetry-broken states in two-dimensional polariton condensates

We consider the existence, stability and dynamics of the nodeless state and fundamental nonlinear excitations, such as vortices, for a quasi-two-dimensional polariton condensate in the presence of pumping and nonlinear damping. We find a series of interesting features that can be directly contrasted to the case of the typically energy-conserving ultracold alkali-atom Bose-Einstein condensates (BECs). For sizeable parameter ranges, in line with earlier findings, the nodeless state becomes unstable towards the formation of stable nonlinear single or multi-vortex excitations. The potential instability of the single vortex is also examined and is found to possess similar characteristics to those of the nodeless cloud. We also report that, contrary to what is known, e.g., for the atomic BEC case, stable stationary gray ring solitons (that can be thought of as radial forms of Nozaki-Bekki holes) can be found for polariton condensates in suitable parametric regimes. In other regimes, however, these may also suffer symmetry-breaking instabilities. The dynamical, pattern-forming implications of the above instabilities are explored through direct numerical simulations and, in turn, give rise to waveforms with triangular or quadrupolar symmetry.

Evidence of DNA damage in humans inhabiting a volcanically active environment: a useful tool for biomonitoring

The present study was designed to evaluate whether chronic exposure to a volcanically active environment might result in genotoxic and cytotoxic effects in human oral epithelial cells. A study group of 120 individuals inhabiting a volcanically active environment (exposed group; Furnas village) and a reference group of 122 individuals inhabiting a village without manifestations of volcanic activity (Santo António village) were examined in this study. Individuals from Furnas village inhabit a volcanically active environment marked by several degassing manifestations, including fumarolic fields, thermal and cold CO₂ springs and soil diffuse degassing areas. For each individual, 1000 buccal epithelial cells were analyzed for the frequency of micronucleated cells (MNC) and the frequency of cells with other nuclear anomalies (ONA: pyknosis, karyolysis and karyorrhexis), by using the micronucleus assay. Information on life-style factors and an informed consent were obtained from each participant. The frequencies of MNC and of ONA per 1000 cells in the exposed group (4.3‰ and 23.5‰, respectively) were significantly higher than in the reference group (1.7‰ and 7.7‰, respectively). The risk of having a high frequency of MNC or ONA was 2.4 and 3.1-fold higher in exposed individuals compared to reference group. The analyzed confounding factors (age, gender, smoking status, alcohol consumption, and mouthwash use) did not show any significant association with the frequency of MNC or ONA. The higher risk of DNA damage in individuals inhabiting a volcanically active environment is for the first time clearly highlighted with this biomonitoring study. Given that MNC in oral epithelia are recognized as a predictive biomarker of cancer risk within a population of healthy subjects, these findings could contribute to explain the high incidence rates of lip, oral cavity and pharynx cancers previously referred for Furnas village inhabitants.

Estragole: a weak direct-acting food-borne genotoxin and potential carcinogen

We evaluated the genotoxicity of the food-flavouring agent estragole in V79 cells using the sister chromatid exchange (SCE) assay and the alkaline comet assay. Unexpectedly, we observed an increase in SCE without an exogenous biotransformation system (S9) and a decrease in its presence. Positive results were also observed in the alkaline comet assay without S9, indicating DNA strand breakage. To ascertain repair of damage, we performed the comet assay in V79 cells after two hours of recovery, and observed a reduction of the genotoxic response. Estragole did not produce strand breaks in plasmid DNA in vitro. We then evaluated the formation of DNA adducts in V79 cells by use of the (32)P-postlabelling assay and detected a dose-dependent formation of DNA adducts, which may be responsible for its genotoxicity. We then assayed estragole in the comet assay with two CHO cell lines, a parental AA8 cell line, and an XRCC1-deficient cell line, EM9. Results confirmed the genotoxicity of estragole without biotransformation in both cell lines, although the genotoxicity in EM9 cells compared with that in AA8 cells was not significantly different, suggesting that the XRCC1 protein is not involved in the repair of estragole-induced lesions. Estragole induces apoptosis, but only with high doses (2000μM), and after long treatment periods (24h). Overall, our results suggest that estragole, besides being metabolized to genotoxic metabolites, is a weak direct-acting genotoxin that forms DNA adducts.

Genotoxicity and endoreduplication inducing activity of the food flavouring eugenol

Eugenol (1-allyl-3-methoxy-4-hydroxybenzene; CAS No. 97-53-0), a compound extracted from clove oil and marjoram, is widely used as a food flavouring substance and is present in spices such as basil, cinnamon and nutmeg. It is also used in dentistry as an antiseptic and analgesic. Structural similarities with the class IIB IARC carcinogen safrole raises questions on its putative carcinogenicity. We evaluated the genotoxicity of eugenol in V79 cells using chromosomal aberrations (CAs), with and without rat liver biotransformation (S9). Eugenol induced CAs, with significant increases (3.5% aberrant cells) at 2500 microM, demonstrating cytotoxicity at higher doses. S9 increased the induction of CAs in a dose-dependent manner to 15% at 2500 microM, with a high frequency of chromatid exchanges. In particular, an increase of endoreduplicated cells was observed, from 0% at control levels to 2.3 and 5% at 2000 microM, without and with S9, respectively. Since endoreduplication has been linked to inhibition of topoisomerase II, the topoisomerase II inhibitor ICRF-193 was used as a control inducer of endoreduplication (0.1-0.5 microM), increasing the number of endoreduplicated cells from 0% (control) to 3.5% (0.5 microM). S9 did not influence endoreduplication by ICRF-193. Both eugenol and ICRF-193 were also assayed for inhibition of topoisomerase II, and both showed a dose-dependent inhibitory effect, with ICRF-193 being a more potent inhibitor. Our results confirm that eugenol is genotoxic and raises the possibility of it having topoisomerase II inhibiting activity.

Lipoperoxidation products and thiol antioxidants in chromium exposed workers

Hexavalent chromium is an established carcinogenic agent, which is not directly reactive with DNA. Its genotoxicity involves a reduction step, producing reactive oxygen species and radicals, and also lower valence forms which form stable complexes with intracellular macromolecules. The trivalent form of chromium may directly react with the genetic material and has also been shown to generate oxidative damage in vitro. To further evaluate the importance of in vivo oxidative DNA damage in the toxicity of each valence form, we conducted a comparative study on hexavalent and trivalent chromium-exposed workers (manual metal arc stainless steel welders and leather tanning workers), focusing on the total oxidative status by quantifying the level of lipoperoxidation products in urine. Thiol antioxidants are important in response to oxidative stress, and therefore, the concentration of glutathione and cysteine in peripheral blood lymphocytes was also determined. Chromium exposure was evaluated by quantifying total chromium in plasma and urine. Both groups had a significant increase in lipid peroxidation products expressed as malondialdehyde (MDA) in urine (tanners 1.42 +/- 0.61 micromol/g creatinine, welders 1.67 +/- 1.13 micromol/g creatinine versus controls 0.81 +/- 0.26 micromol/g creatinine, P < 0.005 in both cases) but only welders had a significant decrease in glutathione concentration in lymphocytes. There was a positive correlation between chromium in plasma and urinary MDA in welders, but not in tanners. This work is part of a larger study of which major results have been published previously including cytogenetics and DNA-protein cross-links in workers exposed to the two different forms of chromium. These results are compared with the results of oxidative damage from this study.

Effect of poly(ADP-ribosyl)ation inhibitors on the genotoxic effects of the boron neutron capture reaction

The boron neutron capture (BNC) reaction results from the interaction of 10B with low-energy thermal neutrons and gives rise to highly damaging lithium and alpha-particles. In this work the genotoxicity caused by the BNC reaction in V79 Chinese hamster cells was evaluated in the presence of poly(ADP-ribosyl)ation inhibitors. Poly(ADP-ribose) polymerase-1 (PARP-1), the most important member of the PARP enzyme family, is considered to be a constitutive factor of the DNA damage surveillance network present in eukaryotic cells, acting through a DNA break sensor function. Inhibition of poly(ADP-ribosyl)ation was achieved with the classical compound 3-aminobenzamide (3-AB), and with two novel and very potent inhibitors, 5-aminoisoquinolinone (5-AIQ) and PJ-34. Dose-response increases in the frequencies of aberrant cells excluding gaps (%ACEG) and chromosomal aberrations excluding gaps per cell (CAEG/cell) were observed for increasing exposures to the BNC reaction. The presence of 3-AB did not increase the %ACEG or CAEG/cell, nor did it change the pattern of the induced chromosomal aberrations. Results with 5-AIQ and PJ-34 were in agreement with the results obtained with 3-AB. We further studied the combined effect of a PARP inhibitor and a DNA-dependent protein kinase (DNA-PK) inhibitors (3-AB and wortmannin, respectively) on the genotoxicity of the BNC reaction, by use of the cytokinesis-block micronucleus assay. DNA-PK is also activated by DNA breaks and binds DNA ends, playing a role of utmost importance in the repair of double-strand breaks. Our results show that the inhibition of poly(ADP-ribosyl)ation does not particularly modify the genotoxicity of the BNC reaction, and that PARP inhibition together with a concomitant inhibition of DNA-PK revealed barely the same sensitizing effect as DNA-PK inhibition per se.

Use of cytogenetic indicators in radiobiology

The study of ionising radiation has systematically relied on cytogenetic indicators to evaluate the biological effects and has led to theoretical approaches to explain observations associated with radiation exposure. In many of the early studies on radiobiology, the induction of chromosomal aberrations was the method of choice to evaluate dose-response relationships. But progressively, this and other cytogenetic biomarkers were used to obtain mechanistic insight on the biological effects induced by radiation. This paper attempts to give a view on the use of cytogenetic indicators in the study of various radiation-related phenomena, including radiation dosimetry, mechanisms involved in the various cellular responses to radiation, such as bystander effects, chromosomal instability and adaptive response, as well as DNA repair pathways. One future direction may involve the use of cytogenetic indicators to evaluate various molecular determinants in individuals' susceptibility to radiation, using other techniques such as fluorescence in situ hybridisation (FISH) and linking them to specific gene functions and single nucleotide polymorphisms.

Elevated levels of DNA-protein crosslinks and micronuclei in peripheral lymphocytes of tannery workers exposed to trivalent chromium

DNA-protein crosslinks (DPC) are a promising biomarker of exposure to hexavalent chromium, a known human carcinogen. Although trivalent chromium is considered to have much lower toxicity, the risk involved in chronic exposure is uncertain. DPC may be a useful tool in clarifying this risk, by signaling an exposure of body tissues to biologically active forms of chromium. DPC quantification was carried out in lymphocytes of a group of tannery workers exposed to trivalent chromium, a small group of manual metal arc stainless steel welders exposed to hexavalent chromium and a control group. This biomarker was compared with the frequency of micronuclei in cytokinesis blocked peripheral lymphocytes as a biomarker of cytogenetic lesions and total plasma and urine chromium levels as an index of exposure. The results indicate a significant increase in the formation of DPC in tannery workers compared with controls (0.88 +/- 0.19 versus 0.57 +/- 0.21%, P < 0.001, Mann-Whitney test) and an even higher level of DPC in welders (2.22 +/- 1.12%, P = 0.03). Tanners showed a significant increase in micronucleated cells compared with controls (6.35 +/- 2.94 versus 3.58 +/- 1.69 per thousand, P < 0.01), whereas in welders this increase was not significant (5.40 +/- 1.67 per thousand ). Urinary chromium was increased in both groups, with a greater increase observed in tanners compared with controls (2.63 +/- 1.62 versus 0.70 +/- 0.38 microg/g creatinine, P < 0.001) than in welders (1.90 +/- 0.37 microg/g creatinine, P < 0.005). Plasma chromium was also increased in both groups (tanners 2.43 +/- 2.11 microg/l, P < 0.001, welders 1.55 +/- 0.67 microg/l, P < 0.005 versus controls 0.41 +/- 0.11 microg/l). In summary, chronic occupational exposure to trivalent chromium can lead to a detectable increase in lymphocyte DNA damage which correlates with a significant exposure of the cells to the metal.

Wortmannin enhances the induction of micronuclei by low and high LET radiation

In mammalian cells, the repair of DNA double-strand breaks (DSBs) is mainly mediated by DNA non-homologous end joining. DNA-dependent protein kinase (DNA-PK), a nuclear serine-threonine kinase and a member of the phosphaditylinositol-3 kinase-related kinase family that is activated by DSBs, is a key component of this pathway. Wortmannin (WM) is known to be an irreversible and potent inhibitor of DNA-PK and has thus been proposed as an effective sensitizer for ionizing radiation and for radiomimetic compounds. The present study, using the cytokinesis block micronucleus assay, reports on the differential effect of WM on the repair of the DNA damage induced by low LET ((60)Co gamma-radiation) and high LET radiation by the boron neutron capture reaction (alpha and Li particles) in V79 Chinese hamster cells. Significant increases in the number of micronuclei per binucleated cell as well as in the frequency of micronucleated binucleated cells were observed in the presence of different concentrations of WM for high LET radiation from the boron neutron capture reaction. The increases observed reached a maximum of approximately 2-fold in comparison with the respective controls. WM, however, had a more pronounced effect on (60)Co gamma-radiation-induced micronuclei, increasing the genotoxic damage from this radiation by approximately 3- to 4-fold. These results are in general in agreement with the concept that DSBs induced by high LET radiation are not a more suitable substrate for the end joining processes mediated by DNA-PK, yet they do not preclude a role for DNA-PK in high LET-induced damage repair.

DNA-PK inhibitor wortmannin enhances DNA damage induced by bleomycin in V79 Chinese hamster cells

The fungal metabolite wortmannin (WM) is a potent and irreversible inhibitor of the enzyme DNA-dependent protein kinase (DNA-PK), a nuclear serine-threonine kinase, member of the phosphaditylinositol-3 kinase related kinase family. WM has been used in the last few years as a promising radiosensitizer mainly throughout cell survival experiments. However, few studies have addressed the role of DNA-PK inhibition in the repair of DNA lesions generated by antitumor agents. Bleomycin (BLM) is an antitumor agent used in the treatment of various neoplasia with a unique genotoxicity profile that mimics the ionizing radiation effects. In this study, we evaluated the effect of different concentrations of WM on the DNA damage induced by BLM. The cytokinesis-block micronucleus assay (CBMN) in V79 Chinese hamster cells was used as the end-point. WM significantly increased the frequency of micronucleated cells (%MNBN) by about 2.2-fold, the number of micronuclei per binucleated cell (MN/BN) by about 2.4-fold, and also changed the pattern of the distribution of micronuclei induced by BLM. The frequency of micronucleated cells with 2 MN per cell and with > or = 3 MN per cell increased, whereas the frequency of micronucleated cells with 1 MN per cell decreased. WM was not genotoxic but decreased cell proliferation as assessed by the frequency of binucleated cells. Our results show that WM clearly enhances the efficacy of BLM in terms of DNA damage inflicted and therefore reinforces its use as a chemosensitizer.

Evaluation of the genotoxic effects of the boron neutron capture reaction in human melanoma cells using the cytokinesis block micronucleus assay

The present work reports on the genotoxicity of the boron neutron capture (BNC) reaction in human metastatic melanoma cells (A2058) assessed by the cytokinesis block micronucleus assay (CBMN) using p-borono-L-phenylalanine (BPA) as the boron delivery agent. Different concentrations of BPA (0.48, 1.2 and 2.4 mM) and different fluences of thermal neutrons were studied. Substantial genotoxic potential of alpha and lithium particles generated inside or near the malignant cell by the BNC reaction was observed in a dose-response manner as measured by the frequency of micronucleated binucleated melanoma cells and by the number of micronuclei (MN) per binucleated cell. The distribution of the number of MN per micronucleated binucleated cell was also studied. The BNC reaction clearly modifies this distribution, increasing the frequency of micronucleated cells with 2 and, especially, > or =3 MN and conversely decreasing the frequency of micronucleated cells with 1 MN. A decrease in cell proliferation was also observed which correlated with MN formation. A discrete genotoxic and anti-proliferative contribution from both thermal neutron irradiation and BPA was observed and should be considered secondary. Additionally, V79 Chinese hamster cells (chromosomal aberrations assay) and human lymphocytes (CBMN assay) incubated with different concentrations of BPA alone did not show any evidence of genotoxicity. The presented results reinforce the usefulness of the CBMN assay as an alternative method for assessment of the deleterious effects induced by high LET radiation produced by the BNC reaction in human melanoma cells.

Mature teratoma of the middle ear

OBJECTIVE

The authors report a case of mature teratoma of the middle ear in a 3-year-old girl with a 1-year history of otitis media.

METHODS AND RESULTS

Radiologic investigation revealed a partially cystic lesion of the petrous portion of the right temporal bone. It produced opacification of the middle ear as well as destruction of septal air cells. The patient underwent a subtotal petrosectomy. Histologically, the tumor was composed of an intimate admixture of mature tissues representing all three germ layers, including brain, myelinated nerve trunks, skeletal muscle, bone, immature cartilage, seromucinous glands, and respiratory epithelium. Of note within the brain tissue was choroid plexus within an ependyma-lined rudimentary ventricle. Immunohistochemical studies were also performed. Twenty months after surgery, the patient was well, with complete recovery from symptoms.

CONCLUSION

Teratomas of the middle ear are rare neoplasms. Only a few examples have been reported. As a rule, they are cured by resection and do not require adjuvant therapy.

No evidence of increased chromosomal aberrations and micronuclei in lymphocytes from nonfamilial thyroid cancer patients prior to radiotherapy

The relationship between the presence of high frequencies of chromosomal aberrations in peripheral lymphocytes and predisposition to cancer has been suggested for some cancer diseases. In nonfamilial thyroid cancer, the few reports available are equivocal. The aim of this study was to assess the possible chromosomal instability in peripheral blood lymphocytes from 22 patients suffering from nonfamilial thyroid cancer. For this purpose, 2 classic cytogenetic assays, the chromosomal aberrations assay and cytokinesis-blocked micronucleus assay, were chosen. The frequency of chromosomal aberrations excluding gaps (%) was 1.68 +/- 1.39 (mean value +/- SD) for the patients group versus 2.20 +/- 1.87 for the control group. The frequency of binucleated lymphocytes with micronuclei ( per thousand) was 5.41 +/- 3.51 (mean value +/- SD) for the patients group versus 5.37 +/- 3.21 for the control group. The results obtained revealed no significant differences between both groups. The present study reinforces the idea that constitutional chromosomal instability in peripheral blood lymphocytes is not visible in nonfamilial thyroid carcinomas.

Using presence-absence data to establish reserve selection procedures that are robust to temporal species turnover

Previous studies suggest that a network of nature reserves with maximum efficiency (obtained by selecting the minimum area such that each species is represented once) is likely to be insufficient to maintain species in the network over time. Here, we test the performance of three selection strategies which require presence-absence data, two of them previously proposed (multiple representations and selecting an increasing percentage of each species' range) and a novel one based on selecting the site where each species has exhibited a higher permanence rate in the past. Multiple representations appear to be a safer strategy than selecting a percentage of range because the former gives priority to rarer species while the latter favours the most widespread. The most effective strategy was the one based on the permanence rate, indicating that the robustness of reserve networks can be improved by adopting reserve selection procedures that integrate information about the relative value of sites. This strategy was also very efficient, suggesting that the investment made in the monitoring schemes may be compensated for by a lower cost in reserve acquisition.

Induction of micronuclei and chromosomal aberrations by the mycotoxin patulin in mammalian cells: role of ascorbic acid as a modulator of patulin clastogenicity

Patulin is a mycotoxin produced by several species of Penicillium, Aspergillus and BYSSOCHLAMYS: Patulin is a common contaminant of ripe apples used for the production of apple juice concentrates and is also present in other fruits, vegetables and food products. Patulin has been reported to have mutagenic, carcinogenic and teratogenic properties. Nevertheless, these properties are still a matter of debate. In this report, we further investigated the genotoxicity of patulin in mammalian cells by two different approaches. Firstly, we evaluated the induction of micronuclei in cytokinesis-blocked human lymphocytes. This approach is important because available data concerning the genetic toxicity of patulin in human cells is sparse. Secondly, we chose an established model for patulin genotoxicity, i.e. the chromosomal aberration assay in V79 Chinese hamster cells, to clarify whether concomitant exposure to ascorbic acid with the mycotoxin modulates or not the clastogenicity of patulin. The results unequivocally show induction of DNA-damaged cells by patulin as assessed by both cytogenetic assays. In addition, an almost complete abolition of patulin (0.8 microM) clastogenicity was observed in the presence of 80 microM ascorbic acid (P < 0.05), showing that although a genetic risk is present, ascorbic acid could somehow partially modulate this problem.

Robustness of reserve selection procedures under temporal species turnover

Complementarity-based algorithms for the selection of reserve networks emphasize the need to represent biodiversity features efficiently, but this may not be sufficient to maintain those features in the long term. Here, we use data from the Common Birds Census in Britain as an exemplar data set to determine guidelines for the selection of reserve networks which are more robust to temporal turnover in features. The extinction patterns found over the 1981-1991 interval suggest that two such guidelines are to represent species in the best sites where they occur (higher local abundance) and to give priority to the rarer species. We tested five reserve selection strategies, one which finds the minimum representation set and others which incorporate the first or both guidelines proposed. Strategies were tested in terms of their efficiency (inversely related to the total area selected) and effectiveness (inversely related to the percentage of species lost) using data on eight pairs of ten-year intervals. The minimum set strategy was always the most efficient, but suffered higher species loss than the others, suggesting that there is a trade-off between efficiency and effectiveness. A desirable compromise can be achieved by embedding the concerns about the long-term maintenance of the biodiversity features of interest in the complementarity-based algorithms.

Chemical features of flavonols affecting their genotoxicity. Potential implications in their use as therapeutical agents

Flavonls are natural compounds present in edible plants and possess several biological activities that can be useful in drug design. Conversely some of these compounds have been shown to be genotoxic to prokaryotic and eukaryotic cells. In this study we tried to establish the chemical features responsible for the genotoxicity of flavonols and to study the conditions that can modulate their genotoxicity namely pH, the presence of antioxidants and metabolism. We assessed the induction of revertants in Salmonella typhimurium TA98 and the induction of Chromosomal aberrations in V79 cells by eight different flavonols and one catechin in the presence and in the absence of metabolizing systems. We have also studied the generation of hydroxyl radical by these flavonoids using the deoxyribose degradation assay. The results obtained in this study suggest that flavonols having a free hydroxyl group at position 3 of the C ring, a free hydroxyl group at position 7 of the A ring and a B ring with a catechol or pyrogallol structure, or a structure that after metabolic activation is transformed into a catechol or a pyrogallol, are flavonols whose genotoxicity in eukaryotic cells depends on their autooxidation. These flavonols can autooxidize when the pH value is slightly alkaline, such as in the intestine, and therefore can induce genotoxicity in humans. Given the above mentioned considerations it is necessary to clarify the mechanisms and the conditions that mediate the biological effects of flavonols before considering them as therapeutical agents.

Assessment of the adaptive response induced by quercetin using the MNCB peripheral blood human lymphocytes assay

Over more than two decades the existence of an adaptive response (AR) has been reported in several cell types and extensively studied with low doses of radiation. Besides radiation, some chemicals [alkylating compounds, mitomycin C (MMC), bleomycin, hydrogen peroxide and metals] may also induce an adaptive response. We have recently reported that the food mutagen quercetin can also induce an adaptive response in V79 Chinese hamster cells. In this work we have studied the effect of low doses of quercetin on the genotoxicity of MMC and bleomycin assessed by the formation of micronuclei in cytokinesis-blocked (MNCB) human peripheral blood lymphocytes. Our results suggest the existence of an AR induced by quercetin in human lymphocytes. Seven of the nine donors studied showed in at least one independent experiment a significant decrease in the frequency of MNCB induced by MMC. The range of these decreases varied between 31 and 58%. In addition, we observed an AR induced by quercetin towards challenging doses of bleomycin. In accordance with other studies with ionizing radiation in which heterogeneity of the AR in the population has been extensively observed, the response here reported also showed some degree of variability between the different donors studied. In view of the results obtained one cannot rule out a possible protective effect of low doses of quercetin leading to adaptation to further exposure to mutagens or carcinogens.