Genetic uniformity and long‐distance clonal dispersal in the invasive androgenetic Corbicula clams

The clam genus Corbicula is an interesting model system to study the evolution of reproductive modes as it includes both sexual and asexual (androgenetic) lineages. While the sexual populations are restricted to the native Asian areas, the androgenetic lineages are widely distributed being also found in America and Europe where they form a major aquatic invasive pest. We investigated the genetic diversity of native and invasive Corbicula populations through a worldwide sampling. The use of mitochondrial and nuclear (microsatellite) markers revealed an extremely low diversity in the invasive populations with only four, undiversified, genetic lineages distributed across Europe and America. On the contrary, in the native populations, both sexual and androgenetic lineages exhibited much higher genetic diversity. Remarkably, the most abundant and widely distributed invasive forms, the so‐called form A and form R found in America and Europe respectively, are fixed for the same single COI (cytochrome c oxydase subunit I) haplotype and same multilocus genotype. This suggests that form R, observed in Europe since the 1980s, derived directly from form A found in America since the 1920s. In addition, this form shares alleles with some Japanese populations, indicating a Japanese origin for this invasive lineage. Finally, our study suggests that few androgenetic Corbicula individuals successfully invaded the non‐native range and then dispersed clonally. This is one striking case of genetic paradox raising the issue of invasive and evolutionary success of genetically undiversified populations.     

TAXONOMIC REVISION OF THE DINOFLAGELLATE AMPHIDOMA CAUDATA: TRANSFER TO THE GENUS AZADINIUM (DINOPHYCEAE) AND PROPOSAL OF TWO VARIETIES,BASED ON MORPHOLOGICAL AND MOLECULAR PHYLOGENETIC ANALYSES1

The systematic position of Amphidoma caudata Halldal within the genus Amphidoma has remained uncertain as a result of its plate formula and the absence of molecular phylogenetic data. Also, this thecate dinoflagellate taxon has been used to designate two distinct morphotypes. The present study aims to clarify the generic affiliation of Amphidoma caudata and the taxonomic value of two different morphotypes M1 and M2. The new examination of the plate formula using SEM showed that it was the same for both morphotypes and that it corresponded to the tabulation of the recent erected genus Azadinium Elbrächter et Tillmann. Morphometric analysis, using cell size, length of apical projection in conjunction with the cell length, and the ratio of horn and spine showed that M1 and M2 formed two distinct groups. These results were supported by a molecular approach, revealing notable differences in the sequences of LSU rDNA and ITS region between these two morphotypes. Phylogenetic analyses inferred either from LSU and combined SSU, ITS region and COI data positioned M1 and M2 in a sister cluster of Azadinium species while Amphidoma languida Tillmann, Salas et Elbrächter, the only species of Amphidoma for which sequence data were available, was situated in a basal position of the Azadinium clade. Thus, we propose the transfer of Amphidoma caudata to the genus Azadinium and, consequently, the rehabilitation of the original tabulation of the genus Amphidoma Stein. To discriminate the two morphotypes, we propose a rank of variety with the following designations: Azadinium caudatum var. caudatum and Azadinium caudatum var. margalefii.     

Postsecondary Education in Industrial Ecology Across the World

In recent years, industrial ecology (IE) has become increasingly integrated into formal education as a distinct body of work. The aim of this article is to describe the state of IE in postsecondary education across the world by providing an inventory of programs and courses offered from a search conducted during the summer of 2012. Although some interpretation of the results is conducted, the aim of this article is to provide a snapshot of the state of IE in higher education in 2012 and serve as a starting point for future work. Data were collected on IE courses and programs across the world by Internet search in order to determine the prevalence of IE in postsecondary curricula. Subsequently, 190 universities and colleges from 46 countries were identified as offering courses and/or programs in IE. From this research, a total of 409 courses and 78 programs were inventoried and course content was analyzed (where available). The results indicate that IE is mainly studied at the graduate level within engineering and environmental disciplines, although undergraduate‐level curricula are emerging. In terms of disciplinary departments offering said curricula, IE is presented as a topic of instruction in varied fields of study, such as business and administration, and the arts. From the course syllabi analyzed, the main subjects being taught within IE education are introductory principles and general tools. Advanced or specialized aspects of the field are also covered, however, less frequently.     

Historical and recent processes shaping the geographic range of a rocky intertidal gastropod: phylogeography,ecology, and habitat availability

Factors shaping the geographic range of a species can be identified when phylogeographic patterns are combined with data on contemporary and historical geographic distribution, range‐wide abundance, habitat/food availability, and through comparisons with codistributed taxa. Here, we evaluate range dynamism and phylogeography of the rocky intertidal gastropod Mexacanthina lugubris lugubris across its geographic range – the Pacific coast of the Baja peninsula and southern California. We sequenced mitochondrial DNA (CO1) from ten populations and compliment these data with museum records, habitat availability and range‐wide field surveys of the distribution and abundance of M. l. lugubris and its primary prey (the barnacle Chthamalus fissus). The geographic range of M. l. lugubris can be characterized by three different events in its history: an old sundering in the mid‐peninsular region of Baja (~ 417,000 years ago) and more recent northern range expansion and southern range contraction. The mid‐peninsular break is shared with many terrestrial and marine species, although M. l. lugubris represents the first mollusc to show it. This common break is often attributed to a hypothesized ancient seaway bisecting the peninsula, but for M. l. lugubris it may result from large habitat gaps in the southern clade. Northern clade populations, particularly near the historical northern limit (prior to the 1970s), have high local abundances and reside in a region with plentiful food and habitat – which makes its northern range conducive to expansion. The observed southern range contraction may result from the opposite scenario, with little food or habitat nearby. Our study highlights the importance of taking an integrative approach to understanding the processes that shape the geographic range of a species via combining range‐wide phylogeography data with temporal geographic distributions and spatial patterns of habitat/food availability.     

Fabrication and Characterization of Native and Oxidized Potato Starch Biodegradable Films

The need to replace conventional polymers due to environmental pollution caused by them has led to increased production of biodegradable polymers such as starch. Thus, the application possibilities of starch have increased. In this study, we produced and characterized biodegradable films derived from native and oxidized potato starch. The film-forming solution was prepared with different concentrations of extracted starch (native or oxidized) and a plasticizer (glycerol or sorbitol). Then, the mechanical, barrier, morphological, and structural properties of the films were characterized. The moisture content of the films varied from 15.35?±?1.31 to 21.78?±?0.49%. The elastic modulus of the films ranged from 219?±?14.97 to 2299?±?62.91 MPa. The film of oxidized starch plasticized with sorbitol in the lowest content was the most resistant and flexible; moreover, this film also presented lower water vapor permeability and low solubility in water. Fourier-transform infrared spectroscopic analysis of the biodegradable films indicated the presence of same functional groups as those of starch with bands in the same regions. The film thickness was lower for the films plasticized with glycerol whereas the color variation (Δ?) was lower for the ones plasticized with sorbitol. In case of both plasticizers, the increase in their content decreased the Δ? value. All the biodegradable films presented stability against water absorption owing to their low solubility in water. Morphological evaluation revealed the presence of partially gelatinized starch granules in the films. The roughness parameter (Rq) of the films varied from 3.39 to 10.9 nm, indicating that their surfaces are smooth. X-ray diffraction studies showed a B-type pattern for the starches, which is representative of tubers. Further, the films present higher relative crystallinity (RC) compared to the starches. The biodegradable starch films are uniform, transparent and with low solubility in water. The oxidation of starch and use of sorbitol as a plasticizer resulted in improved properties of the starch films, which is suitable for application.     

Structural and functional characterization of the N-terminal acetyltransferase Naa50

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Native Prey and Invasive Predator Patterns of Foraging Activity: The Case of the Yellow-Legged Hornet Predation at European Honeybee Hives

Contrary to native predators, which have co-evolved with their prey, alien predators often benefit from native prey naïveté. Vespa velutina, a honeybee predator originating from Eastern China, was introduced into France just before 2004. The present study, based on video recordings of two beehives at an early stage of the invasion process, intends to analyse the alien hornet hunting behaviour on the native prey, Apis mellifera, and to understand the interaction between the activity of the predator and the prey during the day and the season. Chasing hornets spent most of their time hovering facing the hive, to catch flying honeybees returning to the hive. The predation pressure increased during the season confirming previous study based on predator trapping. The number of honeybee captures showed a maximum peak for an intermediate number of V. velutina, unrelated to honeybee activity, suggesting the occurrence of competition between hornets. The number of honeybees caught increased during midday hours while the number of hornets did not vary, suggesting an increase in their efficacy. These results suggest that the impact of V. velutina on honeybees is limited by its own biology and behaviour and did not match the pattern of activity of its prey. Also, it could have been advantageous during the invasion, limiting resource depletion and thus favouring colonisation. This lack of synchronization may also be beneficial for honeybee colonies by giving them an opportunity to increase their activity when the hornets are less effective.     

Effect of vasectomy on gene expression in the epididymis of cynomolgus monkey

Vasectomy has been shown to affect the pattern of mRNA expression of P34H, a human sperm protein added to the acrosomal cap during epididymal transit. It has been reported that vasectomy alters the histology of the reproductive tract in various species as a result of the increased pressure in the epididymis. The aim of this study was to evaluate if other epididymis-specific mRNAs, which are expressed in different patterns along the duct, are altered by vasectomy as well. We analyzed the expression of P31m (a monkey homologue of human P34H) and three different HE-like (HE-l) mRNAs along the epididymis in the cynomolgus monkey (Macaca fascicularis). Sexually mature cynomolgus monkeys were vasectomized unilaterally; then the epididymides were surgically removed at different time points. The ipsilateral normal epididymis was used as a control. Histomorphometric measurements showed that the height of the epididymal epithelial cells started to be affected only at 14 wk postsurgery. However, Northern blot and in situ hybridization analysis showed that the expression pattern of P31m, HE1, and HE5-like mRNA along the epididymis was not affected by vasectomy. Only the HE2-like mRNA predominantly expressed in the normal corpus epididymidis was significantly lowered 14 wk after vasectomy. Thus, ductal obstruction differentially alters mRNA expression along the epididymis of the cynomolgus monkey.     

Two distinct Gb3/CD77 signaling pathways leading to apoptosis are triggered by anti-Gb3/CD77 mAb and verotoxin-1

Globotriasosylceramide (Gb3), a neutral glycosphingolipid, is the B-cell differentiation antigen CD77 and acts as the receptor for most Shiga toxins, including verotoxin-1 (VT-1). We have shown that both anti-Gb3/CD77 mAb and VT-1 induce apoptosis in Burkitt's lymphoma cells. We compared the apoptotic pathways induced by these two molecules by selecting cell lines sensitive to only one of these inducers or to both. In all these cell lines (including the apoptosis-resistant line), VT-1 was transported to the endoplasmic reticulum and inhibited protein synthesis similarly, suggesting that VT-1-induced apoptosis is dissociated from these processes. VT-1 triggered a caspase- and mitochondria-dependent pathway (rapid activation of caspases 8 and 3 associated with a loss of mitochondrial membrane potential (Deltapsim) and the release of cytochrome c from mitochondria). In contrast, the anti-Gb3/CD77 mAb-induced pathway was caspase-independent and only involved partial depolarization of mitochondria. Antioxidant compounds had only marginal effects on VT-1-induced apoptosis but strongly protected cells from anti-Gb3/CD77 mAb-induced apoptosis. VT-1- and anti-Gb3/CD77 mAb-treated cells displayed very different features on electron microscopy. These results clearly indicate that the binding of different ligands to Gb3/CD77 triggers completely different apoptotic pathways.