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Farhan Younas, Nafiseh Soltanmohammadi, Oliver Knapp, Roland Benz
Legionella pneumophila is an aerobic and nonspore-forming pathogenic Gram-negative bacterium of the genus Legionella. It is the causative agent of Legionnaires' disease, also known as Legionellosis. The hosts of this organism are diverse, ranging from simple water borne protozoans such as amoebae to more complex hosts such as macrophages in humans. Genome analyses have shown the presence of genes coding for eukaryotic like proteins in several Legionella species. The presence of these proteins may assist L. pneumophila in its adaptation to the eukaryotic host...
May 19, 2018: Biochimica et Biophysica Acta
David Chetrit, Bo Hu, Peter J Christie, Craig R Roy, Jun Liu
Type IV secretion systems (T4SSs) are complex machines used by bacteria to deliver protein and DNA complexes into target host cells1-5 . Conserved ATPases are essential for T4SS function, but how they coordinate their activities to promote substrate transfer remains poorly understood. Here, we show that the DotB ATPase associates with the Dot-Icm T4SS at the Legionella cell pole through interactions with the DotO ATPase. The structure of the Dot-Icm apparatus was solved in situ by cryo-electron tomography at 3...
May 21, 2018: Nature Microbiology
Jordan V Price, Kallie Jiang, Abigail Galantowicz, Alana Freifeld, Russell E Vance
Toll-like receptor stimulation induces a pronounced shift to increased glycolytic metabolism in mammalian macrophages. We observed that bone marrow-derived macrophages (BMMs) increase glycolysis in response to infection with Legionella pneumophila ( L. pneumophila ), but the role of host macrophage glycolysis on intracellular L. pneumophila replication is not currently understood. Treatment with 2-deoxyglucose (2DG) blocks L. pneumophila replication in mammalian macrophages but has no effect on bacteria grown in broth...
May 21, 2018: Journal of Bacteriology
Isaac Benowitz, Robert Fitzhenry, Christopher Boyd, Michelle Dickinson, Michael Levy, Ying Lin, Elizabeth Nazarian, Belinda Ostrowsky, Teresa Passaretti, Jennifer Rakeman, Amy Saylors, Elena Shamoonian, Terry-Ann Smith, Sharon Balter
We investigated an outbreak of eight Legionnaires' disease cases among persons living in an urban residential community of 60,000 people. Possible environmental sources included two active cooling towers (air-conditioning units for large buildings) <1 km from patient residences, a market misting system, a community-wide water system used for heating and cooling, and potable water. To support a timely public health response, we used real-time polymerase chain reaction (PCR) to identify Legionella DNA in environmental samples within hours of specimen collection...
April 2018: Journal of Environmental Health
Tomoya Nishino
No abstract text is available yet for this article.
May 18, 2018: Internal Medicine
Achille De Battisti, Paolo Formaglio, Sergio Ferro, Mustafa Al Aukidy, Paola Verlicchi
Lab-scale experiments using real groundwater were carried out using the CabECO® reactor system in order to evaluate its suitability for producing safe water, acceptable for civil purposes. Trials were carried out in discontinuous and in continuous mode, analyzing the influence of electrical and hydraulic process parameters on the quality of treated water. The use of highly boron-doped diamond electrodes in the reactor allowed the electrosynthesis of considerable amounts of ozone. Because of the relatively high amount of chloride in the groundwater samples, a mixture of HOCl/ClO- was also synthesized...
May 12, 2018: Chemosphere
Akriti Prashar, María Eugenia Ortiz, Stefanie Lucarelli, Elizabeth Barker, Zohreh Tabatabeiyazdi, Feras Shamoun, Deepa Raju, Costin Antonescu, Cyril Guyard, Mauricio R Terebiznik
Legionella pneumophila (Lp) exhibits different morphologies with varying degrees of virulence. Despite their detection in environmental sources of outbreaks and in respiratory tract secretions and lung autopsies from patients, the filamentous morphotype of Lp remains poorly studied. We previously demonstrated that filamentous Lp invades lung epithelial cells (LECs) and replicates intracellularly in a Legionella containing vacuole. Filamentous Lp activates β1integrin and E-cadherin receptors at the surface of LECs leading to the formation of actin-rich cell membrane structures we termed hooks and membrane wraps...
2018: Frontiers in Cellular and Infection Microbiology
Michele C Hlavsa, Bryanna L Cikesh, Virginia A Roberts, Amy M Kahler, Marissa Vigar, Elizabeth D Hilborn, Timothy J Wade, Dawn M Roellig, Jennifer L Murphy, Lihua Xiao, Kirsten M Yates, Jasen M Kunz, Matthew J Arduino, Sujan C Reddy, Kathleen E Fullerton, Laura A Cooley, Michael J Beach, Vincent R Hill, Jonathan S Yoder
Outbreaks associated with exposure to treated recreational water can be caused by pathogens or chemicals in venues such as pools, hot tubs/spas, and interactive water play venues (i.e., water playgrounds). During 2000-2014, public health officials from 46 states and Puerto Rico reported 493 outbreaks associated with treated recreational water. These outbreaks resulted in at least 27,219 cases and eight deaths. Among the 363 outbreaks with a confirmed infectious etiology, 212 (58%) were caused by Cryptosporidium (which causes predominantly gastrointestinal illness), 57 (16%) by Legionella (which causes Legionnaires' disease, a severe pneumonia, and Pontiac fever, a milder illness with flu-like symptoms), and 47 (13%) by Pseudomonas (which causes folliculitis ["hot tub rash"] and otitis externa ["swimmers' ear"])...
May 18, 2018: MMWR. Morbidity and Mortality Weekly Report
Marie S Prevost, Gabriel Waksman
Human infections by the intracellular bacterial pathogen Legionella pneumophila result in a severe form of pneumonia, the Legionnaire's disease. L. pneumophila utilises a type IVb secretion (T4bS) system termed "dot/icm" to secrete protein effectors to the host cytoplasm. The dot/icm system is powered at least in part by a functionally critical AAA+ ATPase, a protein called DotB, thought to belong to the VirB11 family of proteins. Here we present the crystal structure of DotB at 3.19 Å resolution, in its hexameric form...
May 17, 2018: Protein Science: a Publication of the Protein Society
Samual C Allgood, M Ramona Neunuebel
Bacterial pathogens have developed a wide range of strategies to survive within human cells. A number of pathogens multiply in a vacuolar compartment, while others can rupture the vacuole and replicate in the host cytosol. A common theme among many bacterial pathogens is the use of specialized secretion systems to deliver effector proteins into the host cell. These effectors can manipulate the host's membrane trafficking pathways to remodel the vacuole into a replication-permissive niche and prevent degradation...
May 10, 2018: Cellular Microbiology
K A Hamilton, A J Prussin, W Ahmed, C N Haas
PURPOSE OF REVIEW: The global importance of Legionnaires' disease (LD) and Pontiac fever (PF) has grown in recent years. While sporadic cases of LD and PF do not always provide contextual information for evaluating causes and drivers of Legionella risks, analysis of outbreaks provides an opportunity to assess these factors. RECENT FINDINGS: A review was performed and provides a summary of LD and PF outbreaks between 2006 and 2017. Of the 136 outbreaks, 115 were LD outbreaks, 4 were PF outbreaks, and 17 were mixed outbreaks of LD and PF...
May 9, 2018: Current Environmental Health Reports
Takashi Nishida, Naho Hara, Kenta Watanabe, Takashi Shimizu, Masahiro Fujishima, Masahisa Watarai
Legionella pneumophila is a facultative intracellular Gram-negative bacterium, which is a major causative agent of Legionnaires' disease. In the environment, this bacterium survives in free-living protists such as amoebae and Tetrahymena . The association of L. pneumophila and protists leads to the replication and spread of this bacterium. Thus, from a public health perspective, their association can enhance the risk of L. pneumophila infection for humans. Paramecium spp. are candidates of natural hosts of L...
2018: Frontiers in Microbiology
Zhila Esna Ashari, Nairanjana Dasgupta, Kelly A Brayton, Shira L Broschat
Type IV secretion systems (T4SS) are multi-protein complexes in a number of bacterial pathogens that can translocate proteins and DNA to the host. Most T4SSs function in conjugation and translocate DNA; however, approximately 13% function to secrete proteins, delivering effector proteins into the cytosol of eukaryotic host cells. Upon entry, these effectors manipulate the host cell's machinery for their own benefit, which can result in serious illness or death of the host. For this reason recognition of T4SS effectors has become an important subject...
2018: PloS One
Paolo Fusaroli, Cinzia Ravaioli, Maria Caroli
In order to find the optimal value of the hot water temperature to be reached so that there is no Legionella spp. at the dispensing points, 920 samples of water at temperature between 54 and 60 Celsius degree were analyzed at the Lugo and Faenza hospitals (Ravenna). Thought the analysis of the linear trendline results indicate that the temperature required is close to 60 degrees but as it's difficult to maintain in old plants, a careful patient's risk assessment needs to be carried out and therefore install antibacterial membrane filters at the dispensers...
January 2018: Igiene e Sanità Pubblica
Maren Kirstin Schuhmacher, Monica Rolando, Alexander Bröhm, Sara Weirich, Srikanth Kudithipudi, Carmen Buchrieser, Albert Jeltsch
RomA is a SET-domain containing protein lysine methyltransferase encoded by the Gram-negative bacterium Legionella pneumophila. It is exported into human host cells during infection and has been previously shown to methylate histone H3 at lysine 14 (Rolando et al., 2013, Cell Host Microbe 13:395-405). Here, we investigated the substrate specificity of RomA on peptide arrays showing that it mainly recognizes a G-K-X-(PA) sequence embedded in a basic amino acid sequence context. Based on the specificity profile, we searched for possible additional RomA substrates in the human proteome and identified 34 novel peptide substrates...
May 4, 2018: Journal of Molecular Biology
Yong Wang, Miao Shi, Han Feng, Yalan Zhu, Songqing Liu, Ang Gao, Pu Gao
Ubiquitination constitutes one of the most important signaling mechanisms in eukaryotes. Conventional ubiquitination is catalyzed by the universally conserved E1-E2-E3 three-enzyme cascade in an ATP-dependent manner. The newly identified SidE family effectors of the pathogen Legionella pneumophila ubiquitinate several human proteins by a different mechanism without engaging any of the conventional ubiquitination machinery. We now report the crystal structures of SidE alone and in complex with ubiquitin, NAD, and ADP-ribose, thereby capturing different conformations of SidE before and after ubiquitin and ligand binding...
April 27, 2018: Cell
Nilmini Mendis, Peter McBride, Joseph Saoud, Thangadurai Mani, Sebastien P Faucher
Surviving the nutrient-poor aquatic environment for extended periods of time is important for the transmission of various water-borne pathogens, including Legionella pneumophila (Lp). Previous work concluded that the stringent response and the sigma factor RpoS are essential for the survival of Lp in water. In the present study, we investigated the role of the LetA/S two-component signal transduction system in the successful survival of Lp in water. In addition to cell size reduction in the post-exponential phase, LetS also contributes to cell size reduction when Lp is exposed to water...
April 30, 2018: Scientific Reports
Eva Romay-Lema, Juan Corredoira-Sánchez, Pablo Ventura-Valcárcel, Iria Iñiguez-Vázquez, María-José García Pais, Fernando García-Garrote, Ramón Rabuñal Rey
OBJECTIVE: Most of the data on Legionella pneumonia in our country come from the Mediterranean area, and there are few studies from the Northwest area. This study tries to assess the situation of this infection in this area. METHOD: Retrospective study of all patients with positive Legionella antigenuria treated at the University Hospital Lucus Augusti in Lugo (Spain) from 2001, the year in which this test was introduced in our centre, until 2015. We analysed epidemiological data, risk factors, clinical, radiological and biochemical findings, and clinical outcome...
April 25, 2018: Medicina Clínica
Cherilyn Elwell, Joanne Engel
Intracellular pathogens have developed elegant mechanisms to modulate host endosomal trafficking. The highly conserved retromer pathway has emerged as an important target of viruses and intravacuolar bacteria. Some pathogens require retromer function to survive. For others, retromer activity restricts intracellular growth; these pathogens must disrupt retromer function to survive. In this review, we discuss recent paradigm changes to the current model for retromer assembly and cargo selection. We highlight how the study of pathogen effectors has contributed to these fundamental insights, with a special focus on the biology and structure of two recently described bacterial effectors, Chlamydia trachomatis IncE and Legionella pneumophila RidL...
April 24, 2018: Trends in Microbiology
Qian Jia, Yun Lin, Xuejing Gou, Lei He, Dong Shen, Dongni Chen, Wei Xie, Yongjun Lu
The gram-negative bacterium Legionella pneumophila invades human's lung and causes Legionnaires' disease. To benefit its survival and replication in cellular milieu, L. pneumophila secrets at least 330 effector proteins into host cells. We found that the effector WipA has the protein tyrosine phosphatase (PTP) activity but does not depend on the classical CX5R motif for activity, suggesting that WipA is an unconventional PTP. Meanwhile, the presence of three other highly conserved motifs typically seen in protein serine/threonine phosphatases and the poor inhibition of WipA activity by okadaic acid led us to propose that WipA is a bacterial protein phosphatase...
April 26, 2018: Acta Biochimica et Biophysica Sinica
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