Search results for "SEU"

Iron acquisition from Fe-pyoverdine by Arabidopsis thaliana.

2007

Taking into account the strong iron competition in the rhizosphere and the high affinity of pyoverdines for Fe(III), these molecules are expected to interfere with the iron nutrition of plants, as they do with rhizospheric microbes. The impact of Fe-pyoverdine on iron content of Arabidopsis thaliana was compared with that of Fe-EDTA. Iron chelated to pyoverdine was incorporated in a more efficient way than when chelated to EDTA, leading to increased plant growth of the wild type. A transgenic line of A. thaliana overexpressing ferritin showed a higher iron content than the wild type when supplemented with Fe-EDTA but a lower iron content when supplemented with Fe-pyoverdine despite its inc…

2019

PIWI proteins and their guiding Piwi-interacting (pi-) RNAs direct the silencing of target nucleic acids in the animal germline and soma. Although in mammal testes fetal piRNAs are involved in extensive silencing of transposons, pachytene piRNAs have additionally been shown to act in post-transcriptional gene regulation. The bulk of pachytene piRNAs is produced from large genomic loci, named piRNA clusters. Recently, the presence of reversed pseudogenes within piRNA clusters prompted the idea that piRNAs derived from such sequences might direct regulation of their parent genes. Here, we examine primate piRNA clusters and integrated pseudogenes in a comparative approach to gain a deeper unde…

Cost-efficiency assessments of marine monitoring methods lack rigor—a systematic mapping of literature and an end-user view on optimal cost-efficienc…

2021

Global deterioration of marine ecosystems, together with increasing pressure to use them, has created a demand for new, more efficient and cost-efficient monitoring tools that enable assessing changes in the status of marine ecosystems. However, demonstrating the cost-efficiency of a monitoring method is not straightforward as there are no generally applicable guidelines. Our study provides a systematic literature mapping of methods and criteria that have been proposed or used since the year 2000 to evaluate the cost-efficiency of marine monitoring methods. We aimed to investigate these methods but discovered that examples of actual cost-efficiency assessments in literature were rare, contr…

Protist predation can select for bacteria with lowered susceptibility to infection by lytic phages

2015

Background: Consumer-resource interactions constitute one of the most common types of interspecific antagonistic interaction. In natural communities, complex species interactions are likely to affect the outcomes of reciprocal co-evolution between consumers and their resource species. Individuals face multiple enemies simultaneously, and consequently they need to adapt to several different types of enemy pressures. In this study, we assessed how protist predation affects the susceptibility of bacterial populations to infection by viral parasites, and whether there is an associated cost of defence on the competitive ability of the bacteria. As a study system we used Serratia marcescens and i…

Biogeography of Triassic ammonoids

2015

After the end-Permian mass extinction, ammonoids experienced an explosive recovery followed by episodes of radiation and extinction. These events were associated with sudden biogeographic changes often closely related to major climatic and oceanographic changes. Previous biogeographic studies of Triassic ammonoids have rarely focused on a specific time-interval and were rarely based on quantitative methods. Thus, we will first review biogeographical methods and the biogeographical signals known from Triassic ammonoids. Secondly, we will focus on quantitative approaches that improve our knowledge of ammonoid biogeographical structuring and dynamics during the Triassic, and we will discuss co…

A finding at the Natural History Museum of Florence affords the holotype designation of Orchestia stephenseni Cecchini, 1928 (Crustacea: Amphipoda: T…

2017

The beach flea Orchestia stephenseni has been originally described by Cecchini twice (1928, 1929) from the La Spezia type locality (northern Tyrrhenian Sea, Italy), and successively re-described by Karaman (1973) and Iaciofano & Lo Brutto (2016). 

Environmental impacts on wetland birds: long-term monitoring programmes in the Camargue, France.

2010

10 pages; International audience; Wetlands in the Mediterranean area have become a rare habitat due to human impact. To model the ecology and breeding biology of birds depending on that habitat, we describe long-term studies on two wetland birds (Little Egret Egretta garzetta and Greater Flamingo Phoenicopterus (ruber) roseus) in the Camargue, France. The hydrological conditions in natural Mediterranean wetlands depend largely on the pattern of rainfall (winter) and evapotranspiration (summer), but have been substantially altered by human activities. In natural conditions, these wetlands are very diverse and therefore sustain a high diversity of breeding birds. At the same time their unpred…

Reciprocal Interaction Matrix Reveals Complex Genetic and Dose-Dependent Specificity among Coinfecting Parasites

2012

Understanding genetic specificity in factors determining the outcome of host-parasite interactions is especially important as it contributes to parasite epidemiology, virulence, and maintenance of genetic variation. Such specificity, however, is still generally poorly understood. We examined genetic specificity in interactions among coinfecting parasites. In natural populations, individual hosts are often simultaneously infected by multiple parasite species and genotypes that interact. Such interactions could maintain genetic variation in parasite populations if they are genetically specific so that the relative fitness of parasite genotypes varies across host individuals depending on (1) t…

Colonization of adventitious roots ofMedicago truncatulabyPseudomonas fluorescensC7R12 as affected by arbuscular mycorrhiza

2008

Pseudomonas fluorescens C7R12 was previously shown to promote colonization of Medicago truncatula roots by Glomus mosseae BEG12. To gain more insight into the interaction between C7R12 and BEG12, the cell organization of C7R12 was characterized on adventitious roots mycorrhized or not with BEG12 and on extraradical hyphae. Bacterial cell observations were made using the immuno-fluorescence technique and confocal laser scanning microscopy. Five types of cell organization, so-called organization types (OT), were identified: small or large single cells, cells by pair and cells in microcolonies or in strings. The frequencies of each OT on the roots were expressed as the percentage of observatio…

A mycorrhiza helper bacterium enhances ectomycorrhizal and endomycorrhizal symbiosis of Australian Acacia species.

2003

The aims of this study were to test the effects of a mycorrhiza helper bacterium (MHB), Pseudomonas monteilii strain HR13 on the mycorrhization of (1) an Australian Acacia, A. holosericea, by several ectomycorrhizal fungi or one endomycorrhizal fungus Glomus intraradices, and (2) several Australian Acacia species by Pisolithus alba strain IR100 under glasshouse conditions. Bacterial inoculant HR13 significantly promoted ectomycorrhizal colonization for all the Acacia species, from 45.8% ( A. mangium) to 70.3% ( A. auriculiformis). A stimulating effect of HR13 on the ectomycorrhizal establishment was recorded with all the fungal isolates (strains of Pisolithus and Scleroderma). The same effe…