Search results for "Microbe"
showing 10 items of 114 documents
Morphological and biochemical features of Borrelia burgdorferi pleomorphic forms
2015
The spirochaete bacterium Borrelia burgdorferi sensu lato is the causative agent of Lyme disease, the most common tick-borne infection in the northern hemisphere. There is a long-standing debate regarding the role of pleomorphic forms in Lyme disease pathogenesis, while very little is known about the characteristics of these morphological variants. Here, we present a comprehensive analysis of B. burgdorferi pleomorphic formation in different culturing conditions at physiological temperature. Interestingly, human serum induced the bacterium to change its morphology to round bodies (RBs). In addition, biofilm-like colonies in suspension were found to be part of B. burgdorferi’s normal in vitr…
The Microbiota Promotes Arterial Thrombosis in Low-Density Lipoprotein Receptor-Deficient Mice
2019
Our results demonstrate a functional role for the commensal microbiota in atherothrombosis. In a ferric chloride injury model of the carotid artery, GF C57BL/6J mice had increased occlusion times compared to colonized controls. Interestingly, in late atherosclerosis, HFD-fed GF Ldlr−/− mice had reduced plaque rupture-induced thrombus growth in the carotid artery and diminished ex vivo thrombus formation under arterial flow conditions.
Dectin-1 Stimulation of Hematopoietic Stem and Progenitor Cells Occurs In Vivo and Promotes Differentiation Toward Trained Macrophages via an Indirec…
2020
Invasive candidiasis is an increasingly frequent cause of serious and often fatal infections. Understanding host defense is essential to design novel therapeutic strategies to boost immune protection against Candida albicans. In this article, we delve into two new concepts that have arisen over the last years: (i) the delivery of myelopoiesis-inducing signals by microbial components directly sensed by hematopoietic stem and progenitor cells (HSPCs) and (ii) the concept of “trained innate immunity” that may also apply to HSPCs. We demonstrate that dectin-1 ligation in vivo activates HSPCs and induces their differentiation to trained macrophages by a cell-autonomous indirect mechanism. This p…
Linking Human Milk Oligosaccharides, Infant Fecal Community Types, and Later Risk To Require Antibiotics
2020
Human milk is the sole and recommended nutrition for the newborn infant and contains one of the largest constituents of diverse oligosaccharides, dubbed human milk oligosaccharides (HMOs). Preclinical and clinical association studies indicate that HMOs have multiple physiological functions largely mediated through the establishment of the gut microbiome. Until recently, HMOs were not available to investigate their role in randomized controlled intervention trials. To our knowledge, this is the first report on the effects of 2 HMOs on establishing microbiota in newborn infants. We provide a detailed description of the microbiota changes observed upon feeding a formula with 2 HMOs in comparis…
Advanced time-stamped total data acquisition control front-end for MeV ion beam microscopy and proton beam writing
2013
Many ion-matter interactions exhibit [email protected] time dependences such as, fluorophore emission quenching and ion beam induced charge (IBIC). Conventional event-mode MeV ion microbeam data acquisition systems discard the time information. Here we describe a fast time-stamping data acquisition front-end based on the concurrent processing capabilities of a Field Programmable Gate Array (FPGA). The system is intended for MeV ion microscopy and MeV ion beam lithography. The speed of the system (>240,000 events s^-^1 for four analogue to digital converters (ADC)) is limited by the ADC throughput and data handling speed of the host computer.
Effects of irradiation damage on the back-scattering of electrons: silicon-implanted silicon
2007
Radiation damage in an (initially crystalline) silicon wafer was generated by microbeam implantation with 600 keV Si+ ions (fluence 5 x 1014 ions/cm²). To produce micro-areas with different degrees of damage, 14 implantations at different temperatures (between 23 and 225 °C) were done. The structural state of irradiated areas was characterized using Raman spectroscopy and electron back-scatter diffraction. All irradiated areas showed strong structural damage in surficial regions (estimated depth <1 μm), and at implant substrate temperatures of below 130 °C, the treatment has caused complete amorphization. Back-scattered electron (BSE) images exhibited that observed BSE intensities correlate…
Editorial: Recent Advances in Symbiosis Research: Integrative Approaches
2016
Symbiosis research is being transformed by new model systems and technologies that bring forth unexpected discoveries. Technological advances such as those stemming from Next Generation Sequencing enable detailed insights into the molecular bases of symbiotic relationships, and have revolutionized the study of complex microbial communities. As new data gathers, the need grows for a conceptual framework that helps organize and make sense of the information. Here, we present some ground-breaking works pushing the boundaries of our understanding of symbiosis in a variety of systems, as well as some state-of-the-art attempts at putting forward organizing principles for the whole of symbiology.
Opportunities and Challenges to Microbial Symbiosis Research in the Microbiome Era
2020
Peer reviewed
Early Development of the Gut Microbiota and Immune Health
2014
In recent years, the increase in human microbiome research brought about by the rapidly evolving “omic” technologies has established that the balance among the microbial groups present in the human gut, and their multipronged interactions with the host, are crucial for health. On the other hand, epidemiological and experimental support has also grown for the ‘early programming hypothesis’, according to which factors that act in utero and early in life program the risks for adverse health outcomes later on. The microbiota of the gut develops during infancy, in close interaction with immune development, and with extensive variability across individuals. It follows that the specific process of…
Study of the cwaRS-ldcA Operon Coding a Two-Component System and a Putative L,D-Carboxypeptidase in Lactobacillus paracasei
2020
International audience; The cell surface is the primary recognition site between the bacterium and the host. An operon of three genes, LSEI_0219 (cwaR), LSEI_0220 (cwaS), and LSEI_0221 (ldcA), has been previously identified as required for the establishment of Lactobacillus paracasei in the gut. The genes cwaR and cwaS encode a predicted two-component system (TCS) and ldcA a predicted D-alanyl-D-alanine carboxypeptidase which is a peptidoglycan (PG) biosynthesis enzyme. We explored the functionality and the physiological role of these three genes, particularly their impact on the bacterial cell wall architecture and on the bacterial adaptation to environmental perturbations in the gut. The …