The Temporal Expression of Global Regulator Protein CsrA Is Dually Regulated by ClpP During the Biphasic Life Cycle of Legionella pneumophila

In conclusion, our results show that the growth-stage-specific expression level of CsrA is dually regulated by ClpP-dependent proteolysis at both the transcription and protein levels during the biphasic life cycle of L. pneumophila.
Source: Frontiers in Microbiology - Category: Microbiology Source Type: research

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It was previously determined that the type II secretion system (T2SS) promotes the ability of Legionella pneumophila to grow in coculture with amoebae. Here, we discerned the stage of intracellular infection that is potentiated by comparing the wild-type and T2SS mutant legionellae for their capacity to parasitize Acanthamoeba castellanii. Whereas the mutant behaved normally for entry into the host cells and subsequent evasion of degradative lysosomes, it was impaired in the ability to replicate, with that defect being first evident at approximately 9 h postentry. The replication defect was initially documented in three wa...
Source: Infection and Immunity - Category: Infectious Diseases Authors: Tags: Cellular Microbiology: Pathogen-Host Cell Molecular Interactions Source Type: research
In conclusion, candidate fitness factors of the new Francisella species F-W12 were identified using the scatter screen method which might also be usable for other Francisella species. PMID: 31451389 [PubMed - as supplied by publisher]
Source: International Journal of Medical Microbiology - Category: Microbiology Authors: Tags: Int J Med Microbiol Source Type: research
Abstract Legionella pneumophila resides in multispecies biofilms, where it infects and replicates in environmental protozoa such as Acanthamoeba castellanii. Studies on L. pneumophila physiology and host-pathogen interactions are frequently conducted using clonal bacterial populations and population level analysis, overlooking the remarkable differences in single cell behavior. The fastidious nutrient requirements of extracellular L. pneumophila and the extraordinary motility of Acanthamoeba castellanii hamper an analysis at single cell resolution. In this chapter, we describe a method to study L. pneumophila and ...
Source: Mol Biol Cell - Category: Molecular Biology Authors: Tags: Methods Mol Biol Source Type: research
Abstract The amoeba-resistant bacterium Legionella pneumophila infects humans through aerosols and thereby can cause a life-threatening pneumonia termed Legionnaires' disease. In the environment L. pneumophila forms and colonizes biofilms, which usually comprise complex multispecies communities. In these biofilms L. pneumophila persists and replicates intracellularly in protozoa, such as the amoeba Acanthamoeba castellanii. The interactions between sessile L. pneumophila in biofilms and their natural protozoan hosts are not understood on a molecular level. Here, we describe a method to visualize by confocal m...
Source: Mol Biol Cell - Category: Molecular Biology Authors: Tags: Methods Mol Biol Source Type: research
cute;ndez J Abstract Despite all safety efforts, drinking and wastewater can still be contaminated by Legionella and free-living amoebae (FLA) since these microorganisms are capable of resisting disinfection treatments. An amoebae cyst harboring pathogenic Legionella spp. can be a transporter of this organism, protecting it and enhancing its infection abilities. Therefore, the aim of this work is to identify by DVC-FISH viable Legionella spp and Legionella pneumophila cells inside FLA from water sources in a specific and rapid way with the aim of assessing the real risk of these waters. A total of 55 water samples...
Source: Environmental Research - Category: Environmental Health Authors: Tags: Environ Res Source Type: research
Abstract Prolific growth of pathogenic Legionella pneumophila within engineered water systems and premise plumbing, and human exposure to aerosols containing this bacterium results in the leading health burden of any water-related pathogen in developed regions. Ecologically, free-living amoebae (FLA) are an important group of the microbial community that influence biofilm bacterial diversity in the piped-water environment. Using fluorescent microscopy, we studied in-situ the colonization of L. pneumophila in the presence of two water-related FLA species, Willaertia magna and Acanthamoeba polyphaga in drinking wate...
Source: International Journal of Hygiene and Environmental health - Category: Environmental Health Authors: Tags: Int J Hyg Environ Health Source Type: research
In this study we used a ubiquitous amoeba and their bacterial endosymbiont to investigate the impact of this common association on L. pneumophila infection. We demonstrate that Acanthamoeba castellanii harboring the chlamydial symbiont Protochlamydia amoebophila were able to erase L. pneumophila and, in contrast to symbiont-free amoebae, survived the infection and were able to resume growth. Environmental amoeba isolates harboring P. amoebophila were equally well-protected, and fresh environmental isolates of L. pneumophila were equally well-erased, suggesting ecological relevance of this symbiont-mediated protection. We f...
Source: GEO: Gene Expression Omnibus - Category: Genetics & Stem Cells Tags: Expression profiling by high throughput sequencing Acanthamoeba castellanii Candidatus Protochlamydia amoebophila Legionella pneumophila Source Type: research
Authors: Inoue H, Agata K, Ohta H Abstract  Legionella spp. exist naturally in association with amoeba in water environments and are known to be the etiological agent of a severe form of pneumonia. To detect diverse Legionella populations in cooling tower water systems, amoebic coculturing was performed for 15 water samples obtained from five different kinds of facilities in six geographically different locations. The growth of Legionella in coculture with Acanthamoeba sp. cells was monitored by quantitative PCR targeting Legionella-specific 16S rRNA genes. Seven out of the 15 samples were positive for Legionella...
Source: Biocontrol Science - Category: Microbiology Tags: Biocontrol Sci Source Type: research
Authors: Nomura H, Takahashi S, Tohara Y, Isshiki Y, Sakuda K, Sakuma K, Kondo S Abstract Acanthamoeba castellanii, a ubiquitous organism in water environments, is pathogenic toward humans and also is a host for bacteria of the genus Legionella, a causative agent of legionellosis. Fragrance ingredients were investigated for their antibacterial activity against planktonic Legionella pneumophila, amoebicidal activity against A. castellanii, and inhibitory effect against L. pneumophila uptake into A. castellanii. Helional® exhibited relatively high antibacterial activity [minimum inhibitory concentration (MIC) , 3...
Source: Biocontrol Science - Category: Microbiology Tags: Biocontrol Sci Source Type: research
The gammaproteobacterium Legionella pneumophila is the causative agent of Legionnaires’ disease, an atypical pneumonia that manifests itself with severe lung damage. L. pneumophila, a common inhabitant of freshwater environments, replicates in free-living amoebae and persists in biofilms in natural and man-made water systems. Its environmental versatility is reflected in its ability to survive and grow within a broad temperature range as well as its capability to colonize and infect a wide range of hosts, including protozoa and humans. Peptidyl-prolyl-cis/trans-isomerases (PPIases) are multifunctional proteins that a...
Source: Infection and Immunity - Category: Infectious Diseases Authors: Tags: Bacterial Infections Source Type: research
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