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[Display omitted] • Synthetic amorphous silica is the authorized food additive Silicon dioxide or E551. • A 90-day oral toxicity study was performed at dose levels close to human exposure through E551. • Male reproductive system is not target showing no histophatological or genotoxic effects. • In female no histophatological/genotoxic effects in ovary and limited effects in uterus. • The study identified a limited concern only for female reproductive health. Synthetic amorphous silica (SAS) consists of agglomerates and aggregates of primary particles in the nanorange (<100 nm) and it is the E551 authorized food additive. The potential risks for human health associated to dietary exposure to SAS are not completely assessed; in particular, data on male and female reproductive systems are lacking. A 90-day oral toxicity study with pyrogenic SAS nanomaterial NM-203 was carried out on the basis of the OECD test guideline 408 in the frame of the NANoREG project. Adult Sprague-Dawley rats of both sexes were orally treated for 90 days with 0, 2, 5, 10, 20 and 50 mg SAS/kg bw per day. Dose levels were selected to be as close as possible to the expected human exposure to food additive E551. The present paper provides specific information on potential effects on male and female reproductive systems, through the evaluation of serum biomarkers, sperm count, histopathological analysis of testis, epididymis, ovary and uterus and real-time PCR on uterus; potential genotoxic alterations were evaluated by comet assay on testis, sperm and ovary. NM-203 did not induce histophatological and genotoxic effects in male reproductive system. In female rats, ovary is not target of NM-203 and only tissue-specific effects on uterus were recorded up to 10 mg/kg bw per day. To our best knowledge, this is the first study providing data on male and female reproductive systems after long-term, repeated oral exposure at dose levels close to dietary human exposure, which identifies a limited concern only for female reproductive health. [ABSTRACT FROM AUTHOR]

Aquatic angiosperms have evolved from a diverse assemblage of terrestrial lineages and exhibit broad variation in morphology, life history, and reproductive systems. This variation reflects evolutionary modifications that have occurred following transitions to aquatic habitats, and adaptation to the wealth of ecological niches that occur in wetland environments. Despite this variation, nearly all perennial aquatic plants share one important feature: propagation through both sexual and clonal reproduction. These contrasting reproductive modes involve the formation of propagules that differ in size, resource status, and genetic identity. Accordingly, the balance between sexual and clonal reproduction has important ecological and evolutionary consequences for dispersal, recruitment, and spatial patterns of genetic diversity within and among populations. Here, we review the diversity of aquatic plant life histories and reproductive modes and consider: (1) their effects on patterns of dispersal across spatial scales ranging from the local population to inter-continental transport; (2) how clonality affects sexual fitness via trade-offs and mating patterns; (3) the roles of sexual versus clonal reproduction in population establishment and in the subsequent spread of invasive aquatic plants; (4) how the contrasting properties of sexually- versus clonally-derived propagules in terms of dispersal and competition potentially influence patterns of selection on reproductive mode; (5) the roles of phenotypic plasticity, somatic mutations and epigenetic inheritance in promoting invasion success in widespread clonal aquatic species. We conclude our review by identifying profitable areas for future enquiry in an effort to provide a robust agenda for future research on the ecology and evolution of aquatic plants. [ABSTRACT FROM AUTHOR]

Abstract: Marathrum is a Neotropical genus of Podostemaceae that has been recognized for its elevated degree of vegetative polymorphism. Marathrum rubrum Novelo & Philbrick and Marathrum schiedeanum Cham. represent a clear example: are these distinct species or morphological variants determined by the environment? Three populations were analyzed where we carried out intra-population manual cross-pollinations and compared these to heterospecific pollinations and open-pollinations (control) to test for the presence of reproductive barriers between species. Pollen tube development, seed production, seed size, and germination were observed in legitimate and heterospecific crosses. Our results indicate that there are no reproductive barriers between these species, since we did not find differences in abundance and/or distribution of pollen tubes among pollination treatments. Significant differences among populations in the average number of ovules were found. Similarly, seed number differed among pollination treatments. In general, heterospecific crosses produced less seeds than manual cross-pollinations and open-pollinated flowers. Average seed size was larger for heterospecific crosses than manual cross-pollinations and open-pollinations, whereas no differences in seed germination among populations or pollination treatments were detected. The results support the hypothesis that these ‘species’ constitute morphological variants of the same species. These results are consistent with the proposal that M. rubrum and M. schiedeanum are conspecific with the more widespread Mesoamerican species Marathrum foeniculaceum Bonpl. [Copyright &y& Elsevier]

Abstract: Trypanosoma cruzi, the agent of Chagas disease, is usually subdivided into six discrete typing units (DTUs), TcI to TcVI, among which TcI and TcV are most common in human infections in Bolivia. Multilocus microsatellite typing (MLMT) was selected to further explore the structure of the natural populations belonging to these DTUs. The analysis showed that microsatellite clustering does not fully match the six DTUs, but it is relevant for the within DTUs analyses. Population genetics analysis was conducted on 11 relevant subsamples of stocks from Bolivia and Peru, belonging to TcI (6) and TcV (5), defined by four criterions: DTU, vector species, geographic origin, and date of isolation. Most TcV strains presented the same multilocus genotype over all subsamples with the puzzling characteristic that five loci were heterozygous and the other five homozygous. In TcI, four clusters were defined according to the vector species. Most of them appeared in agreement with clonal propagation (stocks isolated from Triatoma infestans and Triatoma sordida), while a few highly homozygous stocks (e.g. those isolated from Rhodnius stali) suggested that scarce sex events can occur. The poor role played by spatio-temporal factors in describing the observed genetic diversity suggested that ecology, in particular as regard to host played a significant role. These results highlight the extreme heterogeneity of T. cruzi and suggest that further population genetics surveys will need to target the most possible precise spatio-temporal and ecological scales. [Copyright &y& Elsevier]

Artificial l ight a t n ight (ALAN) is a major driver of firefly population declines, but its physiological effects are not well understood. To investigate the impact of ALAN on firefly development, we exposed larval Aquatica ficta fireflies to ALAN for two weeks. High larval mortality was observed in the periods of 1–68 days and 106–134 days post-treatment, which may represent the short- and long-term impacts of ALAN. We then profiled the transcriptome of larval Aquatica ficta fireflies following two weeks of ALAN exposure. A total of 1262 (1.67% out of 75777 unigenes) were differentially expressed in the treatment group: 1157 were down-regulated, and 105 were up-regulated. Up-regulated unigenes were related to regulation of hormone levels, ecdysteroid metabolic process, and response to stimulus; down-regulated unigenes were related to negative regulation of insulin receptor signaling, germ cell development, oogenesis, spermatid development, and regulation of neuron differentiation. Transcriptome results suggest that the endocrine, reproductive, and neural development of firefly larvae could be impaired by even relatively brief period of ALAN exposure. This report contributes a much-needed molecular perspective to the growing body of research documenting the fitness impacts of ALAN on bioluminescent fireflies. [Display omitted] • Two weeks of ALAN treatment increased the mortality rate of A. ficta larvae. • A total of 1262 unigenes (1.67%) were affected following ALAN treatment. • Regulation of hormone levels were up-regulated after ALAN treatment. • Reproductive systems were down-regulated after ALAN treatment. [ABSTRACT FROM AUTHOR]