Extremely uniform lasing wavelengths of InP microdisk lasers heterogeneously integrated on SOI

A standard deviation in lasing wavelength lower than 500pm is characterized on nominally identical and optically-pumped microdisk lasers, heterogeneously integrated on the same SOI circuit. This lasing wavelength uniformity is obtained using electron-beam lithography

Diversité du phytoplancton et autres protistes le long de deux continuums estuariens (Complémentarité des approches morphologique et moléculaire)

Located at the interface between inland aquatic systems and the coastal oceans, estuaries form complex and variable habitats for planktonic microorganisms. As a transition zone linking terrestrial and marine biomes, the structure like a continuum is an essential characteristic of the estuaries. However, these ecosystems are rarely considered in their full extent, in terms of biological composition and assemblages. The objective of this work was to provide more detailed insights into the diversity of phytoplankton communities and the other protists that can develop along a whole estuarine continuum. This study also aimed to characterize the changes in biodiversity and the distribution patterns of the taxa along the gradient. In order to have an overview of the different types of structures and biodiversity that can exist in estuaries, two contrasting ecosystems, under different climatic, environmental and human pressures, were analyzed. Phytoplankton community composition was estimated along the continuum using the traditional microscopical approach, and the protistan genetic diversity was explored through the construction of 18S rRNA gene clone libraries in three contrasting zones of the estuarine gradient. The complementarity of both morphological and molecular approaches is highlighted here; thus, neither should be put aside in the overall study of communities in their natural environment. A significant part of the microbial eukaryotic diversity has not yet been discovered in such complex ecosystems.Situés à l interface entre les systèmes aquatiques continentaux et l océan, les milieux estuariens fournissent des habitats complexes et variables pour les microorganismes planctoniques d origine marine et dulcicole. En tant que transition spatiale entre biomes marins et terrestres, la structure en continuum des estuaires est une caractéristique essentielle. Pourtant, ces écosystèmes sont rarement étudiés dans toute leur étendue en termes de composition et d assemblages biologiques. L objectif de ce travail était de fournir une image plus complète de la diversité des communautés phytoplanctoniques et des autres protistes pélagiques, susceptibles d occuper et de se développer le long d un continuum estuarien total. Cette étude visait aussi à caractériser les changements de biodiversité et les motifs de répartition des taxons au sein du gradient. Afin d avoir un aperçu contrasté du type de structure et de diversité biologique estuarienne pouvant exister, deux écosystèmes aux caractéristiques différentes en termes d influences climatiques, environnementales, anthropiques etc., ont été analysés. La composition phytoplanctonique a été examinée par approche en microscopie le long du continuum, et la diversité génétique des protistes en général a été explorée dans trois zones caractéristiques du gradient estuarien par l analyse de banques de clones de l ADNr 18S. La complémentarité des deux approches morphologique et moléculaire est ici mise en évidence ; aucune d entre-elles ne devrait être omise lors de l étude globale des communautés dans leur milieu naturel. L étendue de la diversité eucaryotique microbienne dans ces écosystèmes complexes ne semble pas avoir encore été totalement appréhendée.CAEN-BU Sciences et STAPS (141182103) / SudocSudocFranceF

First Isolation and Characterization of Bacteria from the Core’s Cooling Pool of an Operating Nuclear Reactor

International audienceMicrobial life can thrive in the most inhospitable places, such as nuclear facilities with high levels of ionizing radiation. Using direct meta-analyses, we have previously highlighted the presence of bacteria belonging to twenty-five different genera in the highly radioactive water of the cooling pool of an operating nuclear reactor core. In the present study, we further characterize this specific environment by isolating and identifying some of these microorganisms and assessing their radiotolerance and their ability to decontaminate uranium. This metal is one of the major radioactive contaminants of anthropogenic origin in the environment due to the nuclear and mining industries and agricultural practices. The microorganisms isolated when sampling was performed during the reactor operation consisted mainly of Actinobacteria and Firmicutes, whereas Proteobacteria were dominant when sampling was performed during the reactor shutdown. We investigated their tolerance to gamma radiation under different conditions. Most of the bacterial strains studied were able to survive 200 Gy irradiation. Some were even able to withstand 1 kGy, with four of them showing more than 10% survival at this dose. We also assessed their uranium uptake capacity. Seven strains were able to remove almost all the uranium from a 5 µM solution. Four strains displayed high efficiency in decontaminating a 50 µM uranium solution, demonstrating promising potential for use in bioremediation processes in environments contaminated by radionuclides

Complex patterns in phytoplankton and microeukaryote diversity along the estuarine continuum

International audienceEstuaries and coastal lagoons are included within the transitional waters category, according to the Water Framework Directive. However, criteria for their differentiation and characterisation are still under discussion and require more research. In particular, detailed observations of biodiversity in more complex transitional and coastal waters are lacking. Microscopic and molecular analyses were therefore used to investigate phytoplankton diversity and spatial community structure, in early spring, along the freshwater-to-marine continuum of the Segura River (Spain), an intensively regulated semiarid basin discharging into the Mediterranean Sea. In addition to the salinity gradient as the major factor determining taxa distribution, influence of multiple anthropogenic and climatic impacting factors (drought, confined waters, irrigation canal) leads to a significant spatial heterogeneity of the aquatic habitat types associated with variations in community composition. Several shifts within the phytoplankton distribution pattern along the continuum are revealed using multivariate analyses. An impressive bloom of the cryptophyte Plagioselmis prolonga occurred in the mixing zone, associated with a typical euryhaline community indicative of eutrophication. The 18S rDNA diversity revealed a microeukaryotic richness including several little-known groups, heterotrophic representatives, and potential parasites. By combining morphological and molecular approaches we revealed the presence of a ‘hidden’ diversity often neglected in traditional surveys

Phytoplankton Diversity and Community Composition along the Estuarine Gradient of a Temperate Macrotidal Ecosystem: Combined Morphological and Molecular Approaches

International audienc

Isolated Splenic Metastases of Her2+++ Gastroesophageal Junction Adenocarcinoma

Isolated metastases from gastric adenocarcinoma to the spleen are very infrequent. Usually, there are multiple metastases from gastric cancer, and isolated splenic metastases are very rare [Lam and Tang: Arch Pathol Lab Med 2000;124:526-530] because of certain anatomical and physiological characteristics (e.g., angulation between the splenic artery and celiac trunk, paucity of afferent lymph flow toward the spleen, contractility of the spleen and major immune content). Here, we report 2 cases of isolated splenic metastases from an adenocarcinoma of the gastroesophageal junction, both with long-term survival outcome and overexpression of Her2

Proteotyping Environmental Microorganisms by Phylopeptidomics: Case Study Screening Water from a Radioactive Material Storage Pool

International audienceThe microbial diversity encompassed by the environmental biosphere is largely unexplored, although it represents an extensive source of new knowledge and potentially of novel enzymatic catalysts for biotechnological applications. To determine the taxonomy of microorganisms, proteotyping by tandem mass spectrometry has proved its efficiency. Its latest extension, phylopeptidomics, adds a biomass quantitation perspective for mixtures of microorganisms. Here, we present an application of phylopeptidomics to rapidly and sensitively screen microorganisms sampled from an industrial environment, i.e., a pool where radioactive material is stored. The power of this methodology is demonstrated through the identification of both prokaryotes and eukaryotes, whether as pure isolates or present as mixtures or consortia. In this study, we established accurate taxonomical identification of environmental prokaryotes belonging to the Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria phyla, as well as eukaryotes from the Ascomycota phylum. The results presented illustrate the potential of tandem mass spectrometry proteotyping, in particular phylopeptidomics, to screen for and rapidly identify microorganisms

Recent advances in proteotyping pathogens and environmental microorganisms by tandem mass spectrometry

International audienceQuestion. Tandem mass spectrometry-based proteotyping of microorganisms has key advantages over other approaches. Due to a greater number of signals recorded, the methodology allows the identification of microorganisms at highly resolved taxonomic levels and can manage complex samples (Grenga et al., 2019). Here, we document its application to pathogens and environmental microorganisms, test its sensitivity and explore the possibility of high-throughput for culturomics. Methods. Peptides generated with trypsin were analyzed by means of several high resolution instruments (LTQ-Orbitrap XL, Q-Exactive HF, Exploris480 mass spectrometers) operated in data-dependent acquisition mode. MS/MS spectra were identified using a cascade of searches conceived for maximizing metaproteomics results against a giant database comprising all sequenced genomes to date. The taxonomy of the microorganisms was established on the basis of the taxon-specific peptides and the taxon-assigned MS/MS spectra. Results. The distribution of assigned Taxon-Spectrum Matches according to the taxa present in the database was modeled, leading to the discovery of the “Phylopeptidomic” signature (Pible et al., 2020). This signature makes it possible to quantify the biomass of each microorganism present in a mixture. Sample preparation for proteotyping has been improved to analyze hundreds of isolates (Hayoun et al., 2019 & 2020), making this methodology truly amenable to culturomics. The proteotyping approach can be applied to clinical pathogens as well as poorly documented environmental microorganisms, whatever the branch of the Tree of Life. We further documented the methodology showing that the sensitivity of the method is 10E4 bacterial cells required for typing at the species level. Finally, a multiplexing methodology was developed to be able to analyze dozens of isolates per analytical run, and identify their potential antibiotic resistance at the same time. Conclusions. Overall, tandem mass spectrometry-based proteotyping is an interesting application of proteomics for rapid microbiological taxonomy. The taxonomic identification without a priori and the characterization of resistance to antibiotics pave the way for a new revolution in the clinical microbiology laboratory.References.Hayoun K, Gaillard JC, Pible O, Alpha-Bazin B, Armengaud J (2020) J. Proteomics 226:103887. Gouveia D, Grenga L, Pible O, Armengaud J (2020) Environ Microbiol. 22(8):2996-3004. Pible O, Allain F, Jouffret V, Culotta K, Miotello G, Armengaud J (2020) Microbiome 8:30. Hayoun K, Gouveia D, Grenga L, Pible O, Armengaud J, Alpha-Bazin B (2019) Frontiers in Microbiol10:1985. Grenga L, Pible O, Armengaud J (2019) Clinical Mass Spectrometry 14:9-17