José Manuel Pérez Martín

Use of space and resources in a Mediterranean population of the butterfly Euphydryas aurinia

Abstract Population parameters of a central Spanish population of the marsh fritillary butterfly, Euphydryas aurinia (Rott.), were studied between 1990 and 1991. Numbers were very similar in the two study years, but adult emergence was delayed 15 days in the second year as a consequence of variation in weather conditions. The nectar sources used by adults were different in the two years and were correlated with the most abundant plants available during the flight period. Adult abundance was correlated with the presence of the larval foodplant (Lonicera periclymenum) in open woodland and was higher where this habitat was mixed with open areas, where nectar sources abound. Estimates of male population numbers were higher than those of females, suggesting that males used wider ranges than females, or a higher residence rate for males. Nevertheless mobility did not differ significantly between the sexes. The conservation of the species in central Spain depends on maintaining patches of oak woodlands, important for the presence of larval foodplants. Large numbers of the butterfly in the Natural Park study area are favoured by traditional management including charcoal production and extensive grazing by cattle and goats.

Oxidative DNA damage contributes to the toxic activity of propylparaben in mammalian cells

Propyl p-hydroxybenzoate, commonly referred to as propylparaben, is the most frequently used preservative to inhibit microbial growth and extend shelf life of a range of consumer products. The objective of this study was to provide further insight into the toxicological profile of this compound, because of the current discrepancy in the literature with regard to the safety of parabens. The Vero cell line, derived from the kidney of the green monkey, was selected to evaluate the adverse effects of propylparaben by use of a set of mechanistically relevant endpoints for detecting cytotoxicity and genotoxic activities. Our results demonstrate that exposure to the compound for 24h causes changes in cell-proliferation rates rather than in cell viability. A significant and dose-dependent decline in the percentage of mitotic cells was observed at the lowest concentration tested, mainly due to cell-cycle arrest at the G0/G1 phase. Immunodetection techniques revealed that induction of DNA double-strand breaks and oxidative damage underlies the cytostatic effect observed in treated Vero cells. Additional studies are in progress to extend these findings, which define a novel mode of action of propylparaben in cultured mammalian cells.

AN EXPLORATORY MULTIVARIATE APPROACH TO DRUG CONSUMPTION PATTERNS IN YOUNG PEOPLE BASED ON PRIMARY SOCIALIZATION THEORY

Drug consumption patterns and their psychosocial conditioning factors are explored on the basis of Primary Socialization Theory (PST), through the application of a questionnaire to a representative sample (N = 650) of the young population (age 15 to 29 years) in the Madrid Region. Cluster analysis identifies five consumption groups. Discriminant analysis, including indicators about subjects integration in primary socialization environments, beliefs about the effects of drugs, indicators of psychosocial wellbeing, and variables related to leisure time, allows 67.45% of correct consumption group prediction. Complex associations between drug use, socialization environments and psychosocial wellbeing are found, calling into question approaches establishing cumulative or unidimensional relationships between posited “risk factors” and drug consumption.

The antioxidant butylated hydroxyanisole potentiates the toxic effects of propylparaben in cultured mammalian cells.

Butylated hydroxyanisole and propylparaben are phenolic preservatives commonly used in food, pharmaceutical and personal care products. Both chemicals have been subjected to extensive toxicological studies, due to the growing concern regarding their possible impacts on environmental and human health. However, the cytotoxicity and underlying mechanisms of co-exposure to these compounds have not been explored. In this study, a set of relevant cytotoxicity endpoints including cell viability and proliferation, oxidative stress, DNA damage and gene expression changes were analyzed to assess whether the antioxidant butylated hydroxyanisole could prevent the pro-oxidant effects caused by propylparaben in Vero cells. We demonstrated that binary mixtures of both chemicals induce greater cytotoxic effects than those reported after single exposureto each compound. Simultaneous treatment with butylated hydroxyanisole and propylparaben caused G0/G1 cell cycle arrest as a result of enhanced generation of oxidative stress and DNA double strand breaks. DNA microarray analysis revealed that a cross-talk between transforming growth factor beta (TGFβ) and ataxia-telangiectasia mutated kinase (ATM) pathways regulates the response of Vero cells to the tested compounds in binary mixture. Our findings indicate that butylated hydroxyanisole potentiates the pro-oxidant effects of propylparaben in cultured mammalian cells and provide useful information for their safety assessment.

Immature stages of Hipparchia Fabricius and the systematics of the ‘Satyrus series» (Lepidoptera: Nymphalidae: Satyrinae)

Abstract. Characters of potential use from the eggs and larvae of four species of Hipparchia (subgenera Hipparchia, Parahipparchia, Neohipparchia and Pseudotergumia) are described. These characters, together with previously published information on larval, pupal and adult morphology, are used to construct a seventy‐one character matrix for Hipparchia and four other genera of the ‘Satyrus series’ (Miller, 1968): Arethusana, Kanetisa, Chazara and Satyrus. The cladistic relationships among these genera and the relative contribution of adult and immature data sets are discussed. A list of possible synapomorphies of the immature stages of the ‘Satyrus series’ is proposed.

Toxicological assessment of third generation (G3) poly (amidoamine) dendrimers using the Allium cepa test

Abstract Despite the expected increase of nanotechnology applications, limited information is currently available on the occurrence, fate and negative impact of engineered nanosized particles in the environment. Plants are an integral and essential part of the ecosystems and their response to nanomaterials exposure is therefore of great interest. In this work, different parameters including root growth, mitotic index and chromosome aberrations were used to estimate the potential ecotoxicity of low generation (G3) hydroxyl- and amine-terminated poly(amidoamine) dendrimers using the Allium cepa test. The findings of the present study indicate that both tested dendrimers produce toxic effects in a higher plant system. The analysis of macroscopic parameters, used in testing for general toxicity, revealed reduction of mean root length in bulbs exposed to high concentrations. In parallel, we observed a decrease in the mitotic activity of root meristems which was associated with severe defects in chromosome segregation. Our results may greatly contribute to characterize the toxicological profile and risk of these potentially emerging pollutants in the environment.

Morphology and morphometry of Lycaenid eggs (Lepidoptera: Lycaenidae)

A morphological study with the use of scanning electron microscope of 67 species of Iberian Lycaenidae is presented. The study covers all the genera present in the area and shows an extraordinary variation in chorionic characters that allows egg diagnosis for most species. A morphometric study showed that the eggs from the sample have sizes that are correlated with adult size, but some species showed larger egg size than expected. Species hibernating at the egg stage proved to have on average larger sizes than those overwintering at other stages, probably because this trait might be favourable to endure the adverse conditions taking place during the winter. A cladistic analysis was performed using morphologic and morphometric characters from the egg with the result of poor discriminant power. However, some formal taxonomic groups such as the genera Lycaena and Satyrium were supported by our analysis due to specific apomorphic characters.

Endoplasmic reticulum stress as a novel cellular response to di (2-ethylhexyl) phthalate exposure.

Di (2-ethylhexyl) phthalate is a high-production chemical widely used as a plasticizer for polyvinyl chloride products. Due to its ubiquitous presence in environmental compartments and the constant exposure of the general population through ingestion, inhalation, and dermal absorption, this compound has been subjected to extensive in vivo and in vitro toxicological studies. Despite the available information, research on the cytotoxicity of di (2-ethylhexyl) phthalate in mammalian cells is relatively limited.In this paper, an in vitro multi-parametric approach was used to provide further mechanistic data on the toxic activity of this chemical in Vero and HaCaT cells. Our results reveal that a 24 h exposure to di (2-ethylhexyl) phthalate causes, in both cell lines, an inhibition of cell proliferation that was linked to cell cycle delay at the G1 phase. Concomitantly, the tested compound induces mild endoplasmic reticulum stress which leads to an adaptive rather than a pro-apoptotic response in mammalian cells. These findings demonstrate that there are multiple potential cellular targets of di (2-ethylhexyl) phthalate-induced toxicity and the need to develop further experimental studies for the risk assessment of this ubiquitous plasticizer.

Disruption of the mevalonate pathway induces dNTP depletion and DNA damage

The mevalonate pathway is tightly linked to cell division. Mevalonate derived non-sterol isoprenoids and cholesterol are essential for cell cycle progression and mitosis completion respectively. In the present work, we studied the effects of fluoromevalonate, a competitive inhibitor of mevalonate diphosphate decarboxylase, on cell proliferation and cell cycle progression in both HL-60 and MOLT-4 cells. This enzyme catalyzes the synthesis of isopentenyl diphosphate, the first isoprenoid in the cholesterol biosynthesis pathway, consuming ATP at the same time. Inhibition of mevalonate diphosphate decarboxylase was followed by a rapid accumulation of mevalonate diphosphate and the reduction of ATP concentrations, while the cell content of cholesterol was barely affected. Strikingly, mevalonate diphosphate decarboxylase inhibition also resulted in the depletion of dNTP pools, which has never been reported before. These effects were accompanied by inhibition of cell proliferation and cell cycle arrest at S phase, together with the appearance of γ-H2AX foci and Chk1 activation. Inhibition of Chk1 in cells treated with fluoromevalonate resulted in premature entry into mitosis and massive cell death, indicating that the inhibition of mevalonate diphosphate decarboxylase triggered a DNA damage response. Notably, the supply of exogenously deoxyribonucleosides abolished γ-H2AX formation and prevented the effects of mevalonate diphosphate decarboxylase inhibition on DNA replication and cell growth. The results indicate that dNTP pool depletion caused by mevalonate diphosphate decarboxylase inhibition hampered DNA replication with subsequent DNA damage, which may have important consequences for replication stress and genomic instability.

Programmed Cell Death in Protozoa: An Evolutionary Point of View. The Example of Kinetoplastid Parasites

Programmed cell death (PCD) is a molecular event which plays an essential role in the development of multicellular organisms. However, recent studies indicate that PCD is a mechanism also present in protozoa and unicellular eukaryotes. For instance, it has been recently proposed that some Trypanosomatid parasites have a PCD mechanism descendant from an ancient life form that has actually evolved. Thus, two hypotheses may explain the existence of PCD in protozoa such as Trypanosomatids. First, PCD could simply be a process without a defined function inherited through cell evolution, which is triggered in response to diverse stimuli and stress conditions. Alternatively, PCD might be used by Trypanosomatids as a control mechanism to maximize their biological fitness.