Search results for "Symbiosi"

Phylogenetic analysis of the thiolase family. Implications for the evolutionary origin of peroxisomes

1992

The thiolase family is a widespread group of proteins present in prokaryotes and three cellular compartments of eukaryotes. This fact makes this family interesting in order to study the evolutionary process of eukaryotes. Using the sequence of peroxisomal thiolase from Saccharomyces cerevisiae recently obtained by us and the other known thiolase sequences, a phylogenetic analysis has been carried out. It shows that all these proteins derived from a primitive enzyme, present in the common ancestor of eubacteria and eukaryotes, which evolved into different specialized thiolases confined to various cell compartments. The evolutionary tree obtained is compatible with the endosymbiotic theory fo…

Potential effects of transgenic cotton on soil ecosystem processes in Vietnam.

2008

Overestimation of the strength of size-assortative pairing in taxa with cryptic diversity: a case of Simpson's paradox.

2015

5 pages; International audience; Size-assortative pairing is one of the most common pairing patterns observed in nature and it probably occurs in many taxa with cryptic diversity. Observed patterns of size-assortative pairing in natural populations may thus be influenced by the co-occurrence of noninterbreeding cryptic groups of individuals living in sympatry. To quantify this potential bias, we sampled amphipods from the Gammarus pulex/Gammarus fossarum crustacean species complex in rivers containing two sympatric and morphologically cryptic groups, i.e. molecular operational taxonomic units (MOTUs). Within each river, MOTUs did not interbreed and differed in mean body size. We measured th…

Horizon scanning the European bio‐based economy: a novel approach to the identification of barriers and key policy interventions from stakeholders in…

2016

There is international recognition that developing a climate-smart bioeconomy is essential to the continuation of economic development, reduction of greenhouse gas emissions, and adaptation to climatic change; Bio-based products have an important role in making this transition happen. Supporting policy interventions have been put forward at European and national levels to support innovation and development of bio-based products and services. This study asks whether suggested policy interventions reflect the needs of stakeholders and examines how these needs vary between European regions. This consultation was performed through an online survey of 447 experts actively involved in bio-based r…

Random Tanglegram Partitions (Random TaPas): An Alexandrian Approach to the Cophylogenetic Gordian Knot

2018

Abstract Symbiosis is a key driver of evolutionary novelty and ecological diversity, but our understanding of how macroevolutionary processes originate extant symbiotic associations is still very incomplete. Cophylogenetic tools are used to assess the congruence between the phylogenies of two groups of organisms related by extant associations. If phylogenetic congruence is higher than expected by chance, we conclude that there is cophylogenetic signal in the system under study. However, how to quantify cophylogenetic signal is still an open issue. We present a novel approach, Random Tanglegram Partitions (Random TaPas) that applies a given global-fit method to random partial tanglegrams of …

Changes of the hindgut microbiota due to high-starch diet can be associated with behavioral stress response in horses.

2015

6 pages; International audience; The digestive system of horses is adapted to a high-fiber diet consumed in small amounts over a long time. However, during training, high-starch and low-fiber diets are usually fed which may induce hindgut microbial disturbances and intestinal pain. These diets can be described as alimentary stress. The aim of the present study was to investigate to what extent changes in behavior are associated with alimentary stress and microbial composition changes of the cecal or colonic ecosystem. Six fistulated horses were used. The alimentary stress was a modification of diet from a high-fiber diet (100% hay) to a progressive low-fiber and high-starch diet (from 90% h…

Evolutionary transition to the ectomycorrhizal habit in the genomes of a hyperdiverse lineage of mushroom‐forming fungi

2022

International audience; Summary The ectomycorrhizal (ECM) symbiosis has independently evolved from diverse types of saprotrophic ancestors. In this study, we seek to identify genomic signatures of the transition to the ECM habit within the hyper-diverse Russulaceae. We present comparative analyses of the genomic architecture and the total and secreted gene repertoires of 18 species across the order Russulales of which 13 are newly sequenced, including a representative of a saprotrophic member of Russulaceae, Gloeopeniophorella convolvens. The genomes of ECM Russulaceae are characterized by a loss of genes for plant cell-wall degrading enzymes (PCWDEs), an expansion of genome size through in…

The Genome of Cardinium cBtQ1 Provides Insights into Genome Reduction, Symbiont Motility, and Its Settlement in Bemisia tabaci

2014

International audience; Many insects harbor inherited bacterial endosymbionts. Although some of them are not strictly essential and are considered facultative, they can be a key to host survival under specific environmental conditions, such as parasitoid attacks, climate changes, or insecticide pressures. The whitefly Bemisia tabaci is at the top of the list of organisms inflicting agricultural damage and outbreaks, and changes in its distribution may be associated to global warming. In this work, we have sequenced and analyzed the genome of Cardinium cBtQ1, a facultative bacterial endosymbiont of B. tabaci and propose that it belongs to a new taxonomic family, which also includes Candidatu…

Different strategies to achieve Pb-tolerance by the two Trebouxia algae coexisting in the lichen Ramalina farinacea.

2012

Lichen thalli are permeable to airborne substances, including heavy metals, which are harmful to cell metabolism. Ramalina farinacea shows a moderate tolerance to Pb. This lichen comprises two Trebouxia phycobionts, provisionally referred to as TR1 and TR9, with distinct physiological responses to acute oxidative stress. Thus, there is a more severe decay in photosynthesis and photosynthetic pigments in TR1 than in TR9. Similarly, under oxidative stress, antioxidant enzymes and HSP70 protein decrease in TR1 but increase in TR9. Since Pb toxicity is associated with increased ROS formation, we hypothesized greater Pb tolerance in this phycobiont. Accordingly, the aim of the present study was …

The genetic structure of the cosmopolitan three-partner lichenRamalina farinaceaevidences the concerted diversification of symbionts

2012

The epiphytic lichen Ramalina farinacea is distributed throughout the northern hemisphere in which the same two algal Trebouxia species (provisionally named TR1 and TR9) coexist in every thallus. Ramalina farinacea symbionts were characterized based on the two fungal nuclear loci (nrITS and rpb2 ) along with the primary and secondary structures of nrITS from each Trebouxia species in the Iberian Peninsula and Canary Islands. The results indicated a noticeable genetic differentiation between mycobionts from these two geographic areas and also suggested concerted changes in the three partners of a lichen symbiosis toward two clearly distinguishable ‘holobiont’ lineages. Modeling of ITS2 RNA s…