Facultative Symbiont Infections Affect Aphid Reproduction

Some bacterial symbionts alter their hosts reproduction through various mechanisms that enhance their transmission in the host population. In addition to its obligatory symbiont Buchnera aphidicola, the pea aphid Acyrthosiphon pisum harbors several facultative symbionts influencing several aspects of host ecology. Aphids reproduce by cyclical parthenogenesis whereby clonal and sexual reproduction alternate within the annual life cycle. Many species, including the pea aphid, also show variation in their reproductive mode at the population level, with some lineages reproducing by cyclical parthenogenesis and others by permanent parthenogenesis. While the role of facultative symbionts has been well studied during the parthenogenetic phase of their aphid hosts, very little is known on their possible influence during the sexual phase. Here we investigated whether facultative symbionts modulate the capacity to produce sexual forms in various genetic backgrounds of the pea aphid with controlled symbiont composition and also in different aphid genotypes from natural populations with previously characterized infection status and reproductive mode. We found that most facultative symbionts exhibited detrimental effects on their hosts fitness under sex-inducing conditions in comparison with the reference lines. We also showed that the loss of sexual phase in permanently parthenogenetic lineages of A. pisum was not explained by facultative symbionts. Finally, we demonstrated that Spiroplasma infection annihilated the production of males in the host progeny by inducing a male-killing phenotype, an unexpected result for organisms such as aphids that reproduce primarily through clonal reproduction

Mobility, Expansion and Management of a Multi-Species Scuba Diving Fishery in East Africa

Background: Scuba diving fishing, predominantly targeting sea cucumbers, has been documented to occur in an uncontrolled manner in the Western Indian Ocean and in other tropical regions. Although this type of fishing generally indicates a destructive activity, little attention has been directed towards this category of fishery, a major knowledge gap and barrier to management. Methodology and Principal Findings: With the aim to capture geographic scales, fishing processes and social aspects the scuba diving fishery that operate out of Zanzibar was studied using interviews, discussions, participant observations and catch monitoring. The diving fishery was resilient to resource declines and had expanded to new species, new depths and new fishing grounds, sometimes operating approximately 250 km away from Zanzibar at depths down to 50 meters, as a result of depleted easy-access stock. The diving operations were embedded in a regional and global trade network, and its actors operated in a roving manner on multiple spatial levels, taking advantage of unfair patron-client relationships and of the insufficient management in Zanzibar. Conclusions and Significance: This study illustrates that roving dynamics in fisheries, which have been predominantly addressed on a global scale, also take place at a considerably smaller spatial scale. Importantly, while proposed management of the sea cucumber fishery is often generic to a simplified fishery situation, this study illustrates

Survey of Activated FLT3 Signaling in Leukemia

Activating mutations of FMS-like tyrosine kinase-3 (FLT3) are found in approximately 30% of patients with acute myeloid leukemia (AML). FLT3 is therefore an attractive drug target. However, the molecular mechanisms by which FLT3 mutations lead to cell transformation in AML remain unclear. To develop a better understanding of FLT3 signaling as well as its downstream effectors, we performed detailed phosphoproteomic analysis of FLT3 signaling in human leukemia cells. We identified over 1000 tyrosine phosphorylation sites from about 750 proteins in both AML (wild type and mutant FLT3) and B cell acute lymphoblastic leukemia (normal and amplification of FLT3) cell lines. Furthermore, using stable isotope labeling by amino acids in cell culture (SILAC), we were able to quantified over 400 phosphorylation sites (pTyr, pSer, and pThr) that were responsive to FLT3 inhibition in FLT3 driven human leukemia cell lines. We also extended this phosphoproteomic analysis on bone marrow from primary AML patient samples, and identify over 200 tyrosine and 800 serine/threonine phosphorylation sites in vivo. This study showed that oncogenic FLT3 regulates proteins involving diverse cellular processes and affects multiple signaling pathways in human leukemia that we previously appreciated, such as Fc epsilon RI-mediated signaling, BCR, and CD40 signaling pathways. It provides a valuable resource for investigation of oncogenic FLT3 signaling in human leukemia

Structure of the human ARHG locus encoding the Rho/Rac-like RhoG GTPase

Members of the Rho/Rac/Cdc42Hs family of GTPases have been shown to participate in many aspects of the signaling of cell growth and differentiation. Although the biochemical properties of these GTPases have been extensively studied, very little is known about their gene structure and regulation. RhoG, a member related to Rac and Cdc42Hs, is activated at the transcriptional level in the mid-G1 phase of stimulated fibroblasts. As a first step toward the characterization of the regulatory elements involved in serum-regulated expression, we isolated and determined the structure of the corresponding human locus (ARHG, localized in 11p15.4-p15.5). This is the first gene structure of a member of the Rho/Rac/Cdc42Hs family. At variance with Ras and Rab3A genes, ARHG contains a single intron larger than 20 kb that splits a 62-nt-long 5' noncoding first exon from the rest of the mRNA. The sequences upstream of the cap sites exhibit transcriptional activity. They are G/C-rich and devoid of TATA or CAAT boxes, as found for many housekeeping genes, including Ras genes

Characterization of late response genes sequentially expressed during renewed growth of fibroblastic cells

Many proto-oncogenes are rapidly and transiently activated during the early stages of the cellular transition from a resting G0 state to the DNA synthesis (S) phase. To get better understanding of the gene complexity involved at later stages, we isolated, by cDNA cloning, and identified 17 genes that are activated sequentially during the period of time from proto-oncogene expression to the onset of DNA synthesis in the hamster CCL39 fibroblastic cell line. When protein synthesis is inhibited, induced expression of these genes is unaffected for 10 of them, enhanced for four, in a fashion similar to the immediate-early response genes, and inhibited for three, as observed for delayed early-response genes. In addition to rhoG, a new member of the ras homolog gene family (Vincent et al., 1992), cDNA sequencing indicated that six of them correspond to cytoskeletal proteins (alpha-tubulin, vascular alpha-actin and skeletal gamma-actin), extracellular matrix protein (thrombospondin), secreted protease (plasminogen activator inhibitor-1) and energy-linked transporter (mitochondrial proton/phosphate symporter). This overall survey shows that numerous differentially regulated gene activations are associated with the cell cycle progression, and suggests that proteins involved in cellular reshaping participate actively in the control of cellular growth

Consumer perspectives on coastal fisheries and product labelling in France and Italy

The term ‘coastal fisheries’ designates a form of fishing which is under heavy pressure due to competition by large-scale high sea fishing. Setting up markets for seafood from coastal fisheries might offer possibilities of product differentiation when appreciated by consumers. The aim of this research is to analyse the potential of marketing seafood from coastal fisheries by investigating consumers’ perception of coastal fisheries and their attitudes towards a label for coastal fishery products in France and Italy. This research combined qualitative (focus groups) and quantitative methods (online survey) in two different steps. ‘Coastal fisheries’ were mainly perceived positively, as they provide fresh products, and are healthy and important for coastal areas. Although opinions on labelling in general, and on coastal fisheries specifically, varied widely, about 70% of the respondents were in favour of a coastal fisheries label. The willingness to use a coastal fisheries label increased significantly when domestic origin, high-quality products, eco-friendliness, support of local/coastal communities and artisanal fishing practices were part of this kind of label. It is concluded that using a label for communicating the origin coastal fisheries appears to be promising for the two study countries: France and Italy. A prerequisite for the success of this kind of approach is that the seafood products must fully comply with consumer expectations, as they are of domestic origin, be of very high product quality and fished in an artisanal or eco-friendly manner

Chronic internal exposure to low dose 137Cs induces positive impact on the stability of atherosclerotic plaques by reducing inflammation in ApoE-/- mice

International audienceAfter Chernobyl and Fukushima Daï Chi, two major nuclear accidents, large amounts of radionuclides were released in the environment, mostly caesium 137 (137Cs). Populations living in contaminated territories are chronically exposed to radionuclides by ingestion of contaminated food. However, questions still remain regarding the effects of low dose ionizing radiation exposure on the development and progression of cardiovascular diseases. We therefore investigated the effects of a chronic internal exposure to 137Cs on atherosclerosis in predisposed ApoE-/- mice. Mice were exposed daily to 0, 4, 20 or 100 kBq/l 137Cs in drinking water, corresponding to range of concentrations found in contaminated territories, for 6 or 9 months. We evaluated plaque size and phenotype, inflammatory profile, and oxidative stress status in different experimental groups. Results did not show any differences in atherosclerosis progression between mice exposed to 137Cs and unexposed controls. However, 137Cs exposed mice developed more stable plaques with decreased macrophage content, associated with reduced aortic expression of pro-inflammatory factors (CRP, TNFα, MCP-1, IFNγ) and adhesion molecules (ICAM-1, VCAM-1 and E-selectin). Lesions of mice exposed to 137Cs were also characterized by enhanced collagen and smooth muscle cell content, concurrent with reduced matrix metalloproteinase MMP8 and MMP13 expression. These results suggest that low dose chronic exposure of 137Cs in ApoE-/- mice enhances atherosclerotic lesion stability by inhibiting pro-inflammatory cytokine and MMP production, resulting in collagen-rich plaques with greater smooth muscle cell and less macrophage content. © 2015 Le Gallic et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

France 2072 : Lifestyles at the core of carbon neutrality challenges

International audienceIn this chapter, we propose to explore the conditions under which a stringent target of 1.5°C - written into the Paris Agreement in December 2015 – may be fulfilled at a country level, France, while focusing on energy issues. The analysis horizon spans to 2072 in reference to the Club of Rome’s 1972 Limits to Growth publication, 2072 being the neutral target. To this end, we explore the impact of two contrasting lifestyles for France: the first, named digital, represents an individualistic and technological society, whereas the second, named collective, depicts a society with strong social ties and cooperation between citizens. These scenarios are assessed through different models, each one representing a particular aspect: lifestyles, economy and technologies. While technology-oriented energy models usually omit or over-simplify the lifestyle dimension, the proposed approach gives a more coherent framework for the formulation of alternative demand levels. These demands for energy services enrich the scenario-building process and influence not only the economic system, but also the energy system. The digital society involves significant growth of both GDP and the unemployment rate, and does not result in carbon neutrality, whereas the collective society leads to smaller growth of GDP and a decrease in the unemployment rate, but makes it possible to reach a nil carbon target. These results underline the leverage role of lifestyles in attaining carbon neutrality