74 research outputs found

    18S rDNA Phylogeny of Lamproderma and Allied Genera (Stemonitales, Myxomycetes, Amoebozoa)

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    The phylogenetic position of the slime-mould genus Lamproderma (Myxomycetes, Amoebozoa) challenges traditional taxonomy: although it displays the typical characters of the order Stemonitales, it appears to be sister to Physarales. This study provides a small subunit (18S or SSU) ribosomal RNA gene-based phylogeny of Lamproderma and its allies, with new sequences from 49 specimens in 12 genera. We found that the order Stemonitales and Lamproderma were both ancestral to Physarales and that Lamproderma constitutes several clades intermingled with species of Diacheopsis, Colloderma and Elaeomyxa. We suggest that these genera may have evolved from Lamproderma by multiple losses of fruiting body stalks and that many taxonomic revisions are needed. We found such high genetic diversity within three Lamproderma species that they probably consist of clusters of sibling species. We discuss the contrasts between genetic and morphological divergence and implications for the morphospecies concept, highlighting the phylogenetically most reliable morphological characters and pointing to others that have been overestimated. In addition, we showed that the first part (∼600 bases) of the SSU rDNA gene is a valuable tool for phylogeny in Myxomycetes, since it displayed sufficient variability to distinguish closely related taxa and never failed to cluster together specimens considered of the same species

    Genetic Structure of Two Protist Species (Myxogastria, Amoebozoa) Suggests Asexual Reproduction in Sexual Amoebae

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    Plasmodial slime molds (Myxogastria or Myxomycetes) are common and widespread unicellular organisms that are commonly assumed to have a sexual life cycle culminating with the formation of often macroscopic fruiting bodies that efficiently disseminate spores. However, laboratory studies based on mating compatibility revealed the coexistence of asexual as well as sexual strains. To test this hypothesis in natural populations, we investigated the genetic variability of two species of the genus Lamproderma. Detailed ecological relevés were carried out in 2007 and 2009 in several deep ravines in the Elbsandsteingebirge (Saxony, south-eastern Germany). Morphological characters of 93 specimens of Lamproderma were recorded and genetic analyses, based on the small subunit ribosomal gene, the internal transcribed spacer 1 and partial elongation factor 1α sequences were carried out for 52 specimens. Genetic analyses showed the existence of two major clades, each composed of several discrete lineages. Most of these lineages were composed of several identical sequences (SSU, ITS 1 and EF-1α) which is explained best by an asexual mode of reproduction. Detrended Correspondence Analysis of morphological characters revealed two morphospecies that corresponded to the two major clades, except for one genotype (Lc6), thus challenging the morphospecies concept. Genetic patterns were not related to the geographical distribution: specimens belonging to the same genotype were found in distinct ravines, suggesting effective long-distance dispersal via spores, except for the Lc6 genotype which was found only in one ravine. Implications for the morphological and biological species concept are discussed

    Pro-environmental behaviors: Determinants and obstacles among italian university students

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    none31The awareness of citizens concerning the health risks caused by environmental pollution is growing, but studies on determinants of pro-environmental behaviors have rarely examined health-related aspects. In this study, we investigated these determinants using data from a large survey among Italian university students (15 Universities: 4778 filled questionnaires). Besides the health-related aspects, represented by environmental health risk perception and functional health literacy, we considered social and demographic characteristics (gender, area of residence, sources of information, trust in institutional and non-institutional subjects, and students’ capacity of positive actions, indicated as internal locus of control). The attitudes towards pro-environmental behaviors were positive for more than 70% of students and positively related with health risk perception, internal locus of control, and health literacy. The correspondence between the positive attitudes towards pro-environmental behaviors and the real adoption of such behaviors was approximately 20% for most behaviors, except for the separate collection of waste (60%). Such a discrepancy can be attributable to external obstacles (i.e., lack of time, costs, lack of support). The health-related aspects were linked to the pro-environmental attitudes, but to a lesser extent to pro-environmental behaviors, owing to the complexity of their determinants. However, they should be taken in account in planning education interventions.openCarducci A.; Fiore M.; Azara A.; Bonaccorsi G.; Bortoletto M.; Caggiano G.; Calamusa A.; De Donno A.; De Giglio O.; Dettori M.; Di Giovanni P.; Di Pietro A.; Facciola A.; Federigi I.; Grappasonni I.; Izzotti A.; Libralato G.; Lorini C.; Montagna M.T.; Nicolosi L.K.; Paladino G.; Palomba G.; Petrelli F.; Schiliro T.; Scuri S.; Serio F.; Tesauro M.; Verani M.; Vinceti M.; Violi F.; Ferrante M.Carducci, A.; Fiore, M.; Azara, A.; Bonaccorsi, G.; Bortoletto, M.; Caggiano, G.; Calamusa, A.; De Donno, A.; De Giglio, O.; Dettori, M.; Di Giovanni, P.; Di Pietro, A.; Facciola, A.; Federigi, I.; Grappasonni, I.; Izzotti, A.; Libralato, G.; Lorini, C.; Montagna, M. T.; Nicolosi, L. K.; Paladino, G.; Palomba, G.; Petrelli, F.; Schiliro, T.; Scuri, S.; Serio, F.; Tesauro, M.; Verani, M.; Vinceti, M.; Violi, F.; Ferrante, M

    Intra-Genomic Ribosomal RNA Polymorphism and Morphological Variation in Elphidium macellum Suggests Inter-Specific Hybridization in Foraminifera

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    Elphidium macellum is a benthic foraminifer commonly found in the Patagonian fjords. To test whether its highly variable morphotypes are ecophenotypes or different genotypes, we analysed 70 sequences of the SSU rRNA gene from 25 specimens. Unexpectedly, we identified 11 distinct ribotypes, with up to 5 ribotypes co-occurring within the same specimen. The ribotypes differ by varying blocks of sequence located at the end of stem-loop motifs in the three expansion segments specific to foraminifera. These changes, distinct from typical SNPs and indels, directly affect the structure of the expansion segments. Their mosaic distribution suggests that ribotypes originated by recombination of two or more clusters of ribosomal genes. We propose that this expansion segment polymorphism (ESP) could originate from hybridization of morphologically different populations of Patagonian Elphidium. We speculate that the complex geological history of Patagonia enhanced divergence of coastal foraminiferal species and contributed to increasing genetic and morphological variation
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