Expression of 20 SCPP genes during tooth and bone mineralization in Senegal bichir.

The African bichir (Polypterus senegalus) is a living representative of Polypteriformes. P. senegalus possesses teeth composed of dentin covered by an enameloid cap and a layer of collar enamel on the tooth shaft, as in lepisosteids. A thin layer of enamel matrix can also be found covering the cap enameloid after its maturation and during the collar enamel formation. Teleosts fish do not possess enamel; teeth are protected by cap and collar enameloid, and inversely in sarcopterygians, where teeth are only covered by enamel, with the exception of the cap enameloid in teeth of larval urodeles. The presence of enameloid and enamel in the teeth of the same organism is an opportunity to solve the evolutionary history of the presence of enamel/enameloid in basal actinopterygians. In silico analyses of the jaw transcriptome of a juvenile bichir provided twenty SCPP transcripts. They included enamel, dentin, and bone-specific SCPPs known in sarcopterygians and several actinopterygian-specific SCPPs. The expression of these 20 genes was investigated by in situ hybridizations on jaw sections during tooth and dentary bone formation. A spatiotemporal expression patterns were established and compared with previous studies of SCPP gene expression during enamel/enameloid and bone formation. Similarities and differences were highlighted, and several SCPP transcripts were found specifically expressed during tooth or bone formation suggesting either conserved or new functions of these SCPPs.

Oyster hemolymph is a complex and dynamic ecosystem hosting bacteria, protists and viruses.

BACKGROUND: The impact of the microbiota on host fitness has so far mainly been demonstrated for the bacterial microbiome. We know much less about host-associated protist and viral communities, largely due to technical issues. However, all microorganisms within a microbiome potentially interact with each other as well as with the host and the environment, therefore likely affecting the host health. RESULTS: We set out to explore how environmental and host factors shape the composition and diversity of bacterial, protist and viral microbial communities in the Pacific oyster hemolymph, both in health and disease. To do so, five oyster families differing in susceptibility to the Pacific oyster mortality syndrome were reared in hatchery and transplanted into a natural environment either before or during a disease outbreak. Using metabarcoding and shotgun metagenomics, we demonstrate that hemolymph can be considered as an ecological niche hosting bacterial, protist and viral communities, each of them shaped by different factors and distinct from the corresponding communities in the surrounding seawater. Overall, we found that hemolymph microbiota is more strongly shaped by the environment than by host genetic background. Co-occurrence network analyses suggest a disruption of the microbial network after transplantation into natural environment during both non-infectious and infectious periods. Whereas we could not identify a common microbial community signature for healthy animals, OsHV-1 µVar virus dominated the hemolymph virome during the disease outbreak, without significant modifications of other microbiota components. CONCLUSION: Our study shows that oyster hemolymph is a complex ecosystem containing diverse bacteria, protists and viruses, whose composition and dynamics are primarily determined by the environment. However, all of these are also shaped by oyster genetic backgrounds, indicating they indeed interact with the oyster host and are therefore not only of transient character. Although it seems that the three microbiome components respond independently to environmental conditions, better characterization of hemolymph-associated viruses could change this picture.

[Telemedicine in thrombotic microangiopathies: A way forward in rare diseases requiring emergency care]. / L'activité de télémédecine dans les microangiopathies thrombotiques : un progrès dans les maladies rares nécessitant une prise en charge en urgence.

Thrombotic microangiopathies (TMA) represent rare diseases requiring a high skill for their management that deserved in France the identification of a dedicated National reference center. TMA are short-term life-threatening diseases; however, with an adapted management, their prognosis can be excellent. It is therefore mandatory to recognize and treat them rapidly according to standard guidelines. Telemedicine is a specialized hub consisting of highly skilled staff trained in a specific domain of medicine. The telemedicine activity of a reference center is an important representative indicator of its expertise and recourse ability. It requires to be accurately evaluated and promoted. In this work, we report the French reference center for TMA telemedicine activity since its setting-up. TMA represent an interesting model of diseases that required a specific organization of telemedicine activity to adapt to clinicians demand, which includes particularly the need to answer resorts in real time 24/7.

Epsilon-proteobacterial diversity from a deep-sea hydrothermal vent on the Mid-Atlantic Ridge.

The prokaryotic phylogenetic diversity was determined for a sample associated with an in situ growth chamber deployed for 5 days on a Mid-Atlantic Ridge hydrothermal vent (23 degrees 22'N, 44 degrees 57'W). The DNA was extracted from the sample and the 16S rDNA amplified by PCR. No Archaea were detected in the sample. Eighty-seven clones containing bacterial 16S rDNA inserts were selected. Based on restriction fragment length polymorphism analysis, 47 clones were unique, however, based on comparative sequence analysis some of these were very similar, and thus only 22 clones were selected for full sequence and phylogenetic analysis. The phylotypes were dominated by epsilon-Proteobacteria (66%). The remainder formed a novel lineage within the Proteobacteria (33%). One clone formed a distinct deeply branching lineage, and was a distant relative of the Aquificales. This report further expands the growing evidence that epsilon-Proteobacteria are important members in biogeochemical cycling at deep-sea hydrothermal ecosystems, participating as epibionts and free living bacteria.

Zobellia galactanovorans gen. nov., sp. nov., a marine species of Flavobacteriaceae isolated from a red alga, and classification of [Cytophaga] uliginosa (ZoBell and Upham 1944) Reichenbach 1989 as Zobellia uliginosa gen. nov., comb. nov.

A mesophilic, aerobic, non-flagellated, gliding bacterium, forming yellow colonies and designated DsijT, was isolated from a red alga on the sea-shore of Roscoff, Brittany, France. DsijT was selected for its ability to actively degrade both agars and carrageenans. The Gram-negative cells occurred singly or in pairs as long rods. The temperature range for growth was 13-45 degrees C, with an optimum at 35 degrees C. The pH range for growth at 35 degrees C was from 6.0 to 8.5, with an optimum around pH 7.0. The NaCl concentrations required for growth at 35 degrees C and pH 7.0 ranged from 5 to 60 g l(-1), with an optimum around 25 g l(-1). The G+C content of the genomic DNA was 42-43 mol%. Phylogenetic analysis of 16S rRNA gene sequences indicated that strain DsijT is closely related to [Cytophaga] uliginosa DSM 2061T. Phenotypic features, however, allowed DsijT and [Cytophaga] uliginosa strains to be distinguished on the basis of ten traits (spreading behaviour, assimilation of eight compounds and amylase production). Their total protein profiles were also different and DNA-DNA hybridization experiments confirmed that DsijT constitutes a new species, distinct from [Cytophaga] uliginosa. Based on the phenotypic features and the phylogenetic relationships of the Flavobacteriaceae, a new genus designated Zobellia gen. nov. is proposed to include Zobellia galactanovorans gen. nov., sp. nov., while [Cytophaga] uliginosa becomes Zobellia uliginosa comb. nov. The type strain of Zobellia galactanovorans is DsijT (= DSM 12802T = CIP 106680T).

Methanococcus vulcanius sp. nov., a novel hyperthermophilic methanogen isolated from East Pacific Rise, and identification of Methanococcus sp. DSM 4213T as Methanococcus fervens sp. nov.

An autotrophic, hyperthermophilic methanogen (M7T) was isolated from a deep-sea hydrothermal chimney sample collected on the East Pacific Rise at a depth of 2600 m. The coccoid-shaped cells are flagellated and exhibit a slight tumbling motility. The temperature range for growth at pH 6.5 was 49-89 degrees C, with optimum growth at 80 degrees C. The optimum pH for growth was 6.5, and the optimum NaCl concentration for growth was around 25 g l-1. The new isolate used H2 and CO2 as the only substrates for growth and methane production. Tungsten, selenium and yeast extract stimulated growth significantly. In the presence of CO2 and H2, the organism reduced elemental sulphur to hydrogen sulphide. Growth was inhibited by chloramphenicol and rifampicin, but not by ampicillin, kanamycin, penicillin and streptomycin. The G + C content of the genomic DNA was 31 mol%. As determined by 16S rDNA gene sequence analysis, this organism was closely related to Methanococcus jannaschii strain JAL-1T. However, despite the high percentage of similarity between their 16S rDNA sequences (97.1%), the DNA-DNA hybridization levels between these strains were less than 5%. On the basis of these observations and physiological traits, it is proposed that this organism should be placed in a new species, Methanococcus vulcanius. The type strain is M7T (= DSM 12094T). During the course of this study, the 16S rDNA sequence analysis placed Methanococcus sp. strain AG86T (= DSM 4213T) as a close relative of M. jannaschii strain JAL-1T. However, the weak level of DNA-DNA hybridization with this strain (< 10%) allowed the proposal that strain AG86T also constitutes a new species, Methanococcus fervens.

Multiple patterns of mtDNA reorganization in plants regenerated from different in vitro cultured explants of a single wheat variety.

We have previously shown that tissue cultures derived from various explants of the wheat variety Chinese Spring exhibit organ/tissue-specific changes in the organization of their mitochondrial genome. The aim of this work was to study the influence of passage out of in-vitro culture, and subsequent plant regeneration, on the in vitro "induced" reorganization of this genome. In all cases but one, subgenomic configurations present in both the donor parent and the tissue culture were evident, in corresponding regenerated plants. The presence, in regenerated plants, of subgenomic configurations found in tissue culture but undetectable in the donor parent appeared to be both timeand organ/tissue-dependent. Moreover, when present, these novel organizations were not systematically found in all regenerated plants. Finally, novel subgenomic configurations were specifically detected after passage out of in-vitro culture. As these results were obtained from a single plant variety, they clearly confirm the extreme plasticity of mitochondrial genome structure in response to in-vitro culture.