Genomic evolution and adaptation of arthropod-associated Rickettsia.

Rickettsia species are endosymbionts hosted by arthropods and are known to cause mild to fatal diseases in humans. Here, we analyse the evolution and diversity of 34 Rickettsia species using a pangenomic meta-analysis (80 genomes/41 plasmids). Phylogenomic trees showed that Rickettsia spp.

Culturomics revealed the bacterial constituents of the microbiota of a 10-year-old laboratory culture of planarian species S. mediterranea.

The planarian species Schmidtea mediterranea is a flatworm living in freshwater that is used in the research laboratory as a model to study developmental and regeneration mechanisms, as well as antibacterial mechanisms. However, the cultivable microbial repertoire of the microbes comprising its microbiota remains unknown. Here, we characterized the bacterial constituents of a 10-year-old laboratory culture of planarian species S.

Chryseobacterium schmidteae sp. nov. a novel bacterial species isolated from planarian Schmidtea mediterranea.

Marseille-P9602 is a Chryseobacterium-like strain that we isolated from planarian Schmidtea mediterranea and characterized by taxono-genomic approach. We found that Marseille-P9602 strain exhibits a 16S rRNA gene sequence similarity of 98.76% with Chryseobacterium scophthalmum LMG 13028 strain, the closest phylogenetic neighbor.

Artificially altered gravity elicits cell homeostasis imbalance in planarian worms, and cerium oxide nanoparticles counteract this effect.

Gravity alterations elicit complex and mostly detrimental effects on biological systems. Among these, a prominent role is occupied by oxidative stress, with consequences for tissue homeostasis and development. Studies in altered gravity are relevant for both Earth and space biomedicine, but their implementation using whole organisms is often troublesome.

The Act of Controlling Adult Stem Cell Dynamics: Insights from Animal Models.

Adult stem cells (ASCs) are the undifferentiated cells that possess self-renewal and differentiation abilities. They are present in all major organ systems of the body and are uniquely reserved there during development for tissue maintenance during homeostasis, injury, and infection. They do so by promptly modulating the dynamics of proliferation, differentiation, survival, and migration.

Planarians (Platyhelminthes)-An Emerging Model Organism for Investigating Innate Immune Mechanisms.

An organism responds to the invading pathogens such as bacteria, viruses, protozoans, and fungi by engaging innate and adaptive immune system, which functions by activating various signal transduction pathways. As invertebrate organisms (such as sponges, worms, cnidarians, molluscs, crustaceans, insects, and echinoderms) are devoid of an adaptive immune system, and their defense mechanisms solely rely on innate immune system components. Investigating the immune response in such organisms helps to elucidate the immune mechanisms that vertebrates have inherited or evolved from invertebrates.

Human dental pulp stem cells: A sanctuary for relapsing Bartonella quintana.

Bartonella quintana is a facultative intracellular bacterium responsible for relapsing fever, an example of non-sterilizing immunity. The cellular sanctuary of B. quintana in-between febrile relapses remains unknown but repeated detection of B.

Draft Genome Sequence of Herminiimonas contaminans Strain CCM 7991, a Biopharmaceutical Contaminant.

was described as a new bacterial species, a contaminant isolated from a biopharmaceutical production process in Sweden. Since the genome sequence was not available, we performed draft genome sequencing. The genome of strain CCM 7991 (=CCUG 53591 = DSM 28178 = Marseille-Q4544) was 4,038,814 bp long, with a G+C content of 53.

Draft Genome Sequence of Comamonas jiangduensis Strain YW1.

Here, we report the draft genome sequence of strain YW1 (= DSM 100319 = CSUR Q1714 = CCTCC AB 2012033  =  KACC 16697). is a new species that was isolated from agricultural soil. The genome sequence from strain YW1 has been assembled into 322 contigs for a total size of 2,758,586 bp with a G+C content of 59.

Draft Genome Sequence of Vogesella oryzae L3B39, Isolated from the Rhizosphere of Saline-Tolerant Pokkali Rice.

Here, we report the draft genome sequence of L3B39 (CSUR Q2602 = DSM 28780), which is a species isolated from the rhizosphere of saline-tolerant pokkali rice. The genome sequence was assembled into 58 contigs for a total size of 3,415,129 bp, with a G+C content of 62.3%.

Draft Genome Sequence of Comamonas aquatilis Strain LK (= CSUR P6418 = CECT 9772), Isolated from the Planarian Schmidtea mediterranea.

was defined as a new species based on its 16S rRNA sequence, but the genome from the type strain SB30-Cr27-3 (= CIP 111491 = CCM 8815) is not available. We have cultivated from the planarian a strain, LK (= CSUR P6418 = CECT 9772), that exhibits 100% 16S rRNA sequence similarity to strain SB30-Cr27-3 We have sequenced the genome of strain LK and obtained a chromosome of 4,899,818 bp, with a G+C content of 61.75%, assembled into two contigs.

Pedobacter schmidteae sp. nov., a new bacterium isolated from the microbiota of the planarian Schmidtea mediterranea.

Pedobacter schmidteae sp. nov. strain EG (Collection de Souches de l'Unité des Rickettsie CSUR P6417 = Colección Española de Cultivos Tipo CECT 9771) is a new Pedobacter species isolated from the planarian Schmidtea mediterranea.

[Planarian, an emerging animal model for toxicology studies].

Since a few decades, a new invertebrate animal model has emerged in toxicology studies: the planarian. This non-parasitic flatworm, from phylum Platyhelminthes, has an amazing regenerative capacity and has been described as "immortal under the edge of the knife" in 1814 by Dalyell. This formidable capacity is due to the abundance of stem cells called neoblasts, allowing for a tiny fragment equivalent to 1/279 of the size of the planarian to generate a whole animal.

Evaluation of a robust engineered enzyme towards organophosphorus insecticide bioremediation using planarians as biosensors.

Organophosphorus compounds (OPs) are neurotoxic molecules developed as insecticides and chemical warfare nerve agents (CWNAs). They are covalent inhibitors of acetylcholinesterase (AChE), a key enzyme in central and peripheral nervous systems and are responsible for numerous poisonings worldwide. Many animal models have been studied over the years but finding a suitable in vivo model to account for both acute toxicity and long-term exposure remains a topical issue.

Trained Immunity Carried by Non-immune Cells.

"Trained immunity" is a term proposed by Netea to describe the ability of an organism to develop an exacerbated immunological response to protect against a second infection independent of the adaptative immunity. This immunological memory can last from 1 week to several months and is only described in innate immune cells such as monocytes, macrophages, and natural killer cells. Paradoxically, the lifespan of these cells in the blood is shorter than the duration of trained immunity.

Temperature affects the biology of Schmidtea mediterranea.

Studies of tissue regeneration and host-pathogen interactions using the model planarian Schmidtea mediterranea have been performed at an experimental temperature of 19 °C. S. mediterranea planarians exposed to 19 °C-32 °C were observed for survival, mobility, feeding and regeneration for three months and elimination of the Staphylococcus aureus pathogen over six days.

Glycopeptidolipids, a Double-Edged Sword of the Complex.

is a rapidly-growing species causing a diverse panel of clinical manifestations, ranging from cutaneous infections to severe respiratory disease. Its unique cell wall, contributing largely to drug resistance and to pathogenicity, comprises a vast panoply of complex lipids, among which the glycopeptidolipids (GPLs) have been the focus of intense research. These lipids fulfill various important functions, from sliding motility or biofilm formation to interaction with host cells and intramacrophage trafficking.

In silico analysis of Schmidtea mediterranea TIR domain-containing proteins.

While genetic evidence points towards an absence of Toll-Like Receptors (TLRs) in Platyhelminthes, the Toll/IL-1 Receptor (TIR)-domains that drive the assembly of signalling complexes downstream TLR are present in these organisms. Here, we undertook the characterisation of the repertoire of TIR-domain containing proteins in Schmidtea mediterranea in order to gain valuable information on TLR evolution in metazoan. We report the presence of twenty proteins containing between one and two TIR domains.

Mechanistic and Structural Insights Into the Unique TetR-Dependent Regulation of a Drug Efflux Pump in .

is an emerging human pathogen causing severe pulmonary infections and is refractory to standard antibiotherapy, yet few drug resistance mechanisms have been reported in this organism. Recently, mutations in leading to up-regulation of the MmpS5/MmpL5 efflux pump were linked to increased resistance to thiacetazone derivatives. Herein, the DNA-binding activity of MAB_4384 was investigated by electrophoretic mobility shift assays using the palindromic sequence IR located upstream of .

Role of the immune system in regeneration and its dynamic interplay with adult stem cells.

The immune system plays an indispensable role in the process of tissue regeneration following damage as well as during homeostasis. Inflammation and immune cell recruitment are signs of early onset injury. At the wound site, immune cells not only help to clear debris but also secrete numerous signalling molecules that induce appropriate cell proliferation and differentiation programmes essential for successful regeneration.

Insight into stem cell regulation from sub-lethally irradiated worms.

Despite the significant advances in the comprehension of stem cell control network, the nature of extrinsic signals regulating their dynamic remains to be understood. In this paper, we take advantage of the stem cell repopulation process that follows low-dose X-ray treatment in planarians to identify genes, preferentially enriched in differentiated cells, whose expression is activated during the process. Genetic silencing of some of them impaired the stem cell repopulation, suggesting a tight extrinsic control of stem cell activity.

A Simple and Rapid Gene Disruption Strategy in : On the Design and Application of Glycopeptidolipid Mutants.

Little is known about the disease-causing genetic determinants that are used by , increasingly acknowledged as an important emerging pathogen, notably in cystic fibrosis. The presence or absence of surface exposed glycopeptidolipids (GPL) conditions the smooth (S) or rough (R) subsp. () variants, respectively, which are characterized by distinct infective programs.

Tailed giant Tupanvirus possesses the most complete translational apparatus of the known virosphere.

Here we report the discovery of two Tupanvirus strains, the longest tailed Mimiviridae members isolated in amoebae. Their genomes are 1.44-1.

[Trained immunity in invertebrates: what do we know?].

One of the defense mechanisms of the host is the trained immunity, an immune component of the innate immunity, also known as innate immune memory. The trained immunity is defined as an exacerbated protection of an organism to a foreign body, such as a pathogenic microorganism, upon a second contact with it. This kind of immunity does not involve the components of acquired immunity, such as the B lymphocytes or T lymphocytes.