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

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

Preservation of modern and MIS 5.5 erosional landforms and biological structures as sea level markers : a matter of luck?

The Mediterranean Basin is characterized by a significant variability in tectonic behaviour, ranging from subsidence to uplifting. However, those coastal areas considered to be tectonically stable show coastal landforms at elevations consistent with eustatic and isostatic sea level change models. In particular, geomorphological indicators—such as tidal notches or shore platforms—are often used to define the tectonic stability of the Mediterranean coasts. We present the results of swim surveys in nine rocky coastal sectors in the central Mediterranean Sea using the Geoswim approach. The entire route was covered in 22 days for a total distance of 158.5 km. All surveyed sites are considered to have been tectonically stable since the last interglacial (Marine Isotope Stage 5.5 [MIS 5.5]), because related sea level markers fit well with sea level rise models. The analysis of visual observations and punctual measurements highlighted that, with respect to the total length of surveyed coast, the occurrence of tidal notches, shore platforms, and other indicators accounts for 85% of the modern coastline, and only 1% of the MIS 5.5 equivalent. Therefore, only 1% of the surveyed coast showed the presence of fossil markers of paleo sea levels above the datum. This significant difference is mainly attributable to erosion processes that did not allow the preservation of the geomorphic evidence of past sea level stands. In the end, our research method showed that the feasibility of applying such markers to define long-term tectonic behaviour is much higher in areas where pre-modern indicators have not been erased, such as at sites with hard bedrock previously covered by post-MIS 5.5 continental deposits, e.g., Sardinia, the Egadi Islands, Ansedonia, Gaeta, and Circeo. In general, the chances of finding such preserved indicators are very low.peer-reviewe

Soil protistology rebooted: 30 fundamental questions to start with

Protists are the most diverse eukaryotes. These microbes are keystone organisms of soil ecosystems and regulate essential processes of soil fertility such as nutrient cycling and plant growth. Despite this, protists have received little scientific attention, especially compared to bacteria, fungi and nematodes in soil studies. Recent methodological advances, particularly in molecular biology techniques, have made the study of soil protists more accessible, and have created a resurgence of interest in soil protistology. This ongoing revolution now enables comprehensive investigations of the structure and functioning of soil protist communities, paving the way to a new era in soil biology. Instead of providing an exhaustive review, we provide a synthesis of research gaps that should be prioritized in future studies of soil protistology to guide this rapidly developing research area. Based on a synthesis of expert opinion we propose 30 key questions covering a broad range of topics including evolution, phylogenetics, functional ecology, macroecology, paleoecology, and methodologies. These questions highlight a diversity of topics that will establish soil protistology as a hub discipline connecting different fundamental and applied fields such as ecology, biogeography, evolution, plant-microbe interactions, agronomy, and conservation biology. We are convinced that soil protistology has the potential to be one of the most exciting frontiers in biology

Phytochemical study of Caulerpa racemosa (Forsk.) J. Agarth, an invading alga in the habitat of La Maddalena Archipelago

Caulerpa racemosa is a marine Chlorophyta widely distributed in tropical areas, introduced into the Mediterranean Sea since 1990. It has been invading the Mediterranean Sea causing ecological problems. This invasive event can be considered as one of the most serious in the history of species introduced into the Mediterranean Sea, even if C. racemosa has not triggered as much attention as the famous 'killer alga' Caulerpa taxifolia. The aim of this work is to analyse phytochemically C. racemosa in the northern Sardinia area for secondary metabolites. Marine algae shows the molecular pattern of bis-indole alkaloids, sesquiterpenes, diterpenes and sterols. The intention is to expand phytochemical analysis in order to understand just how significant the anti-tumour, anti-inflammatory and antinociceptive actions can be. © 2014 © 2014 Taylor & Francis.Caulerpa racemosa is a marine Chlorophyta, widely distributed in tropical areas, introduced into the Mediterranean Sea since 1990. It has been invading the Mediterranean Sea, causing ecological problems. This invasive event can be considered as one of the most serious in the history of species introduced into the Mediterranean Sea, even if C. racemosa has not triggered as much attention as the famous ‘‘killer alga’’ Caulerpa taxifolia. The aim of this work is the phytochemical analysis of C. racemosa for the first time investigated in the Northern Sardinia area for secondary metabolites. Marine algae shows the molecular pattern of bis-indole alkaloids, sesquiterpenes, diterpenes and sterols. The intention to expand phytochemical analysis in order to understand just how significant the anti-tumor, anti-inflammatory and antinociceptive actions can b

The Impact of commercial and recreational harvesting for <i>Paracentrotus lividus</i> on shallow rocky reef sea urchin communities in North-western Sardinia, Italy

The fishery for the edible sea urchin Paracentrotus lividus is of great importance to many European regions, although in some of them this species has shown a wide scale decline in recent years. This paper reports on direct (on P. lividus) and indirect (on the co-occurring but not fished echinoid, Arbacia lixula) effects of sea urchin harvesting in shallow rocky reefs in North-western Sardinia (Italy, central-western Mediterranean Sea), where this activity is intensively practised. Density, size (test diameter), and biomass of both species were assessed in autumn 2004 at two locations impacted by P. lividus fishery, and at two controls within an adjacent Marine Protected Area. Density of P. lividus and A. lixula was significantly greater at the controls than at the exploited locations. The average test diameter of P. lividus was also significantly larger at the controls, where large-sized specimens (i.e. &gt;5 cm) were notably more abundant. The average size of A. lixula did not significantly differ between the impacted locations and the controls. The average biomass of P. lividus was significantly greater at the controls than at the exploited locations, whereas no differences were detected for A. lixula. These results reveal the existence of a heavy fishing impact on P. lividus in North-western Sardinia and the need for regulation of its harvesting to prevent severe direct effects on its populations. Since no indirect effects on A. lixula have been detected, it could be hypothesized that this species did not benefit from P. lividus fishery due to an only moderate competition for habitat and resources between these two echinoids. Implications for management of edible sea urchin fishery are also discussed

Phytochemical study of <i>Caulerpa racemosa</i> (Forsk.) J. Agarth, an invading alga in the habitat of La Maddalena Archipelago

<div><p><i>Caulerpa racemosa</i> is a marine Chlorophyta widely distributed in tropical areas, introduced into the Mediterranean Sea since 1990. It has been invading the Mediterranean Sea causing ecological problems. This invasive event can be considered as one of the most serious in the history of species introduced into the Mediterranean Sea, even if <i>C. racemosa</i> has not triggered as much attention as the famous ‘killer alga’ <i>Caulerpa taxifolia</i>. The aim of this work is to analyse phytochemically <i>C. racemosa</i> in the northern Sardinia area for secondary metabolites. Marine algae shows the molecular pattern of bis-indole alkaloids, sesquiterpenes, diterpenes and sterols. The intention is to expand phytochemical analysis in order to understand just how significant the anti-tumour, anti-inflammatory and antinociceptive actions can be.</p></div

Essential oil composition and biological activity from Artemisia caerulescens subsp. densiflora (Viv.) Gamisans ex Kerguélen & Lambinon (Asteraceae), an endemic species in the habitat of La Maddalena Archipelago

The purpose of this study was to investigate the composition of the essential oil obtained from a population of Artemisia caerulescens subsp. densiflora growing in Razzoli, an island in the La Maddalena Archipelago (Sardinia, Italy). A. caerulescens sups. densiflora Viv. (Asteraceae), a wild herb, seldom studied in the Mediterranean, represents one of the many rare endemic species growing in North Sardinia. The essential oil composition was analysed by means of GC/MS analysis, which showed davana ethers as the major volatile components, accounting together for 17.5%, followed by (E)-nerolidol (4.5%), β-oplopenone (3.3%), cis-sabinene hydrate (5.2%) and terpinen-4-ol (4.7%). The oil was tested for antioxidant activity by means of DPPH test, inhibition of lipid oxidation test and hypochlorous acid test, which showed a quite interesting scavenger capacity. For the first time, we reported the cytotoxic activity of the essential oil of A. caerulescens subsp. densiflora, against three human tumour cell lines (A375, MDA-MB231 and HCT116), with IC50 values in the range 5.20-7.61 μg/mL, which deserved further studies to support its use as chemopreventive agent. Finally, the antimicrobial activity of the essential oil, displayed on a panel of human pathogens, was very low