35 research outputs found
ICESsuHN105, a Novel Multiple Antibiotic Resistant ICE in Streptococcus suis Serotype 5 Strain HN105
Streptococcussuis serotype 5, an emerging zoonosis bacterial pathogen, has been isolated from infections in both pigs and humans. In this study, we sequenced the first complete genome of a virulent, multidrug-resistant SS5 strain HN105. The strain HN105 displayed enhanced pathogenicity in zebrafish and BABL/c mouse infection models. Comparative genome analysis identified a novel 80K integrative conjugative element (ICE), ICESsuHN105, as required for the multidrug resistance phenotype. Six corresponding antibiotic resistance genes in this ICE were identified, namely tet (O), tet (M), erm (two copies), aph, and spc. Phylogenetic analysis classified the element as a homolog of the ICESa2603 family, containing the typical family backbone and insertion DNA. DNA hybrids mediated by natural transformation between HN105 and ZY05719 verified the antibiotic resistant genes of ICESsuHN105 that could be transferred successfully, while they were dispersedly inserted with a single gene in different genomic locations of ZY05719(HN105) transformants. To further identify the horizontal transfer of ICESsuHN105 as a whole mobile genetic element, a circular intermediate form of ICESsuHN105 was detected by PCR. However, the effective conjugation using serotype 2 S. suis as recipients was not observed in current assays in vitro. Further studies confirmed the presence of the complete lantibiotic locus encoded in ICESsuHN105 that effectively inhibits the growth of other streptococci. In summary, this study demonstrated the presence of antibiotic resistance genes in ICE that are able to transfer between different clinical isolates and adapt to a broader range of Streptococcus serotype or species
Caractérisation de la déphosphorylation de l'histone H3 induite par Streptococcus pneumoniae
Les modifications de la chromatine, au niveau des histones, sont des régulateurs fondamentaux de l'expression des gènes chez les eucaryotes car elles contrôlent l'accès de la machinerie de transcription aux régions ciblées. Des études récentes ont montré que les modifications de la chromatine induites par des agents pathogènes bactériens interfèrent avec le programme de transcription de l'hôte. Cependant, les mécanismes en jeu sont mal caractérisés et le rôle de ces modifications pour l'hôte ou pour la bactérie reste inconnu. Nous montrons pour la première fois que la bactérie colonisatrice extracellulaire Gram positive Streptococcus pneumoniae induit une modification de l'histone H3 dans les cellules épithéliales respiratoires lors d'une infection in vitro et in vivo. Les facteurs bactériens impliqués dans l'induction de cette modification, PLY et SpxB, sont communs à tous les sérotypes de S. pneumoniae. Nous montrons donc que la déphosphorylation de l'histone H3 est une modification courante induite non seulement par des bactéries pathogènes, mais également par des pneumocoques colonisateurs non virulents. De manière intéressante, l'infection à S. pneumoniae induit une modification post-traductionnelle (déphosphorylation de T320), essentielle à l'activation, de la phosphatase hôte PP1. Nos données montrent que la modification de PP1 est également induite par d'autres toxines bactériennes de la même famille que PLY, suggérant un mécanisme commun d'altération de l'hôte. Nous avons également étudié le rôle de cette modification d'histone au cours de l'infection. Nous avons constaté que, bien que la déphosphorylation de H3 soit en corrélation avec la répression transcriptionnelle des gènes inflammatoires, elle n'était pas nécessaire pour atténuer cet effet. À la place, S. pneumoniae bloque l'activation de la voie NF-KB par la déphosphorylation de P65 S536 et limite l'activation des gènes inflammatoires. Nous montrons également que l'inhibition de PP1 et la déphosphorylation de H3 qui en résulte ont une incidence sur la survie bactérienne. Par conséquent, la capacité des bactéries à induire une déphosphorylation de H3 constitue un avantage et est nécessaire pour une infection productive.Chromatin modifications, at the level of histones, are fundamental regulators of gene expression in eukaryotes as they control the access of the transcriptional machinery to the targeted regions. Recent studies have found that chromatin modifications induced by bacterial pathogens interfere with the host transcriptional program. However, the mechanisms at play are poorly characterized and the role of these modifications for the host or for the bacterium remain unknown. We show for the first time that the extracellular Gram positive colonizing bacterium Streptococcus pneumoniae induces histone modification in respiratory epithelial cells both during in vitro and in vivo infection. The bacterial factors involved in inducing this modification, PLY and SpxB, are common to all S. pneumoniae serotypes, and therefore we reveal that histone H3 dephosphorylation is a common modification induced not only by pathogenic bacteria, but also avirulent colonizing pneumococci. Interestingly, S. pneumoniae infection induces a posttranslational modification (T320 dephosphorylation), essential for activation, of the host phosphatase PP1. Our data show that PP1 modification is also induced by other bacterial toxins in the same family as PLY, suggesting a common mechanism of host alteration. We further investigated the role of this histone modification during infection. We found that although H3 dephosphorylation correlated with transcriptional repression of inflammatory genes, it was not required for mediating this effect. Instead, S. pneumoniae blocks activation of NF-κB pathway through P65 S536 dephosphorylation, and restrict the activation of inflammatory genes. We further show that inhibition of PP1, and the ensuing H3 dephosphorylation impacts bacterial survival. Therefore, the ability of bacteria to induce H3 dephosphorylation provides an advantage and is necessary for a productive infection
Revealing eukaryotic histone-modifying mechanisms through bacterial infection
International audienceIn the long co-evolution of host-pathogen interaction, bacteria have developed sophisticated strategies to manipulate host cell mechanisms and reprogram host transcription. Targeting chromatin, mainly through post-translational modification (PTM) of histone proteins, is one strategy that has been revealed over the last decade. Indeed, histone modifications play a crucial role in regulating transcription during cell type and stimulus specific responses, making them good targets during infection. Therefore, the study of host-pathogen interactions provides breakthroughs in understanding virulence mechanisms, but also in host cell mechanisms. Although chromatin is regulated by DNA methylation, noncoding RNAs, and post-translational modifications of histones, most studies have concentrated on bacteria-induced histone modifications, which will be the focus of this review. We will discuss the different mechanisms used by bacteria to induce histone PTMs, whether it is through direct targeting of pathogen effector enzymes, or indirectly through modulation of cellular signaling cascade. We will summarize the concepts we learned in cell biology from exploring bacteria-triggered histone modifications, by focusing on the signaling cascades modified by bacteria, bacterial mimics of eukaryotic enzymes, and the novel histone marks imposed upon infection
Fault Diagnosis Method for an Underwater Thruster, Based on Load Feature Extraction
Targeting the problem of fault diagnosis in magnetic coupling underwater thrusters, a fault pattern classification method based on load feature extraction is proposed in this paper. By analyzing the output load characteristics of thrusters under typical fault patterns, the load torque model of the thrusters is established, and two characteristic parameters are constructed to describe the different fault patterns of thrusters. Then, a thruster load torque reconstruction method, based on the sliding mode observer (SMO), and the fault characteristic parameter identification method, based on the least square method (LSM), are proposed. According to the identified fault characteristic parameters, a thruster fault pattern classification method based on a support vector machine (SVM) is proposed. Finally, the feasibility and superiority of the proposed aspects are verified, through comparative simulation experiments. The results show that the diagnostic accuracy of this method is higher than 95% within 5 seconds of the thruster fault. The lowest diagnostic accuracy of thrusters with a single failure state is 96.75%, and the average diagnostic accuracy of thrusters with five fault states is 98.65%
Fault Diagnosis Method for an Underwater Thruster, Based on Load Feature Extraction
Targeting the problem of fault diagnosis in magnetic coupling underwater thrusters, a fault pattern classification method based on load feature extraction is proposed in this paper. By analyzing the output load characteristics of thrusters under typical fault patterns, the load torque model of the thrusters is established, and two characteristic parameters are constructed to describe the different fault patterns of thrusters. Then, a thruster load torque reconstruction method, based on the sliding mode observer (SMO), and the fault characteristic parameter identification method, based on the least square method (LSM), are proposed. According to the identified fault characteristic parameters, a thruster fault pattern classification method based on a support vector machine (SVM) is proposed. Finally, the feasibility and superiority of the proposed aspects are verified, through comparative simulation experiments. The results show that the diagnostic accuracy of this method is higher than 95% within 5 seconds of the thruster fault. The lowest diagnostic accuracy of thrusters with a single failure state is 96.75%, and the average diagnostic accuracy of thrusters with five fault states is 98.65%
Bit Error Rate Performance Bounds of SC-FDE under Arbitrary Multipath Mobile Communication Channels in Transportation
This paper focuses on the bit error rate (BER) performance of intelligent transportation communication system under multi-path mobile frequency-selective channels. After presenting the theoretical BER performance formula of single carrier frequency domain equalization (SC-FDE) in the form of double integral, a closed-form approximate upper bound of BER performance was derivedas well as specific analytical expressions for approximate BER performance bounds under typical modulations. Analysis and simulation show that the derived approximate BER bound highly approaches the theoretical one. The bound also indicates that the research about the preferable equalization methods is still necessary
Electric Power Self-Supply Module for WSN Sensor Node Based on MEMS Vibration Energy Harvester
This paper proposes an electric power self-supply module for the wireless sensor network (WSN) sensor node. The module includes an electromagnetic vibration energy harvester based on micro-electro-mechanical system (MEMS) technology and a processing circuit. The vibration energy harvester presented in this paper is fabricated by an integrated microfabrication process and consists of four similar and relatively independent beam vibration elements. The main functions of the processing circuit are to convert the output of the harvester from unstable alternating current (AC) to stable direct current (DC), charge the super capacitor, and ensure the stable output of the super capacitor. The preliminary test results of the harvester chip show that the chip can output discontinuous pulse voltage, and the range of the voltage value is from tens to hundreds of millivolts in the vibration frequency range of 10–90 Hz. The maximum value that can be reached is 563 mV (at the vibration frequency of 18 Hz). The results of the test show that the harvester can output a relatively high voltage, which can meet the general electric power demand of a WSN sensor node
Annotating the Function of the Human Genome with Gene Ontology and Disease Ontology
Increasing evidences indicated that function annotation of human genome in molecular level and phenotype level is very important for systematic analysis of genes. In this study, we presented a framework named Gene2Function to annotate Gene Reference into Functions (GeneRIFs), in which each functional description of GeneRIFs could be annotated by a text mining tool Open Biomedical Annotator (OBA), and each Entrez gene could be mapped to Human Genome Organisation Gene Nomenclature Committee (HGNC) gene symbol. After annotating all the records about human genes of GeneRIFs, 288,869 associations between 13,148 mRNAs and 7,182 terms, 9,496 associations between 948 microRNAs and 533 terms, and 901 associations between 139 long noncoding RNAs (lncRNAs) and 297 terms were obtained as a comprehensive annotation resource of human genome. High consistency of term frequency of individual gene (Pearson correlation = 0.6401, p=2.2e-16) and gene frequency of individual term (Pearson correlation = 0.1298, p=3.686e-14) in GeneRIFs and GOA shows our annotation resource is very reliable
Novel Variant Serotype of Streptococcus suis Isolated from Piglets with Meningitis
Choir apse, general view of the upper apse; Little remains of the abbey's important and influential medieval glazing. The windows of the Rayonnant choir and nave, probably the most important 13th-century ensemble in the Paris region before the glazing of the Sainte-Chapelle, were destroyed in the Revolution. They are documented only in a sketch, one of a series (Compiègne, Mus. Mun. Vivenel) made in 1794-1795 by Charles Percier, and the reliability of even this has been challenged (Lillich). Most of the glass outside of the ambulatory was reconstructed during the 19th century. Source: Grove Art Online; http://www.groveart.com/ (accessed 2/3/2008