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packaging of live legionella pneumophila into pellets expelled by tetrahymena spp. does not require bacterial replication and depends on a dot/icm-mediated survival mechanism.the freshwater ciliate tetrahymena sp. efficiently ingested, but poorly digested, virulent strains of the gram-negative intracellular pathogen legionella pneumophila. ciliates expelled live legionellae packaged in free spherical pellets. the ingested legionellae showed no ultrastructural indicators of cell division either within intracellular food vacuoles or in the expelled pellets, while the number of cfu consistently decreased as a function of time postinoculation, suggesting a lack of l. pne ...200818245233
multigenome analysis identifies a worldwide distributed epidemic legionella pneumophila clone that emerged within a highly diverse species.genomics can provide the basis for understanding the evolution of emerging, lethal human pathogens such as legionella pneumophila, the causative agent of legionnaires' disease. this bacterium replicates within amoebae and persists in the environment as a free-living microbe. among the many legionella species described, l. pneumophila is associated with 90% of human disease and within the 15 serogroups (sg), l. pneumophila sg1 causes over 84% of legionnaires' disease worldwide. why l. pneumophila ...200818256241
lgt: a family of cytotoxic glucosyltransferases produced by legionella pneumophila.legionella pneumophila is a facultative intracellular pathogen responsible for severe lung disease in humans, known as legionellosis or legionnaires' disease. previously, we reported on the approximately 60-kda glucosyltransferase (lgt1) from legionella pneumophila, which modified eukaryotic elongation factor 1a. in the present study, using l. pneumophila philadelphia-1, lens, paris, and corby genome databases, we identified several genes coding for proteins with considerable sequence homology t ...200818281405
legionnaires' disease in immunocompromised patients: a case report of legionella longbeachae pneumonia and review of the literature.in addition to legionella pneumophila, about 20 legionella species have been documented as human pathogens. the majority of infections by non-pneumophila legionella species occur in immunocompromised and splenectomized patients. here, we report a case of 'classical' lobar pneumonia caused by legionella longbeachae in a splenectomized patient receiving corticosteroids for chronic immune thrombocytopenia. tests for legionella antigen were negative. l. longbeachae was immediately detected in bronch ...200818287305
legionella pneumophila infection induces programmed cell death, caspase activation, and release of high-mobility group box 1 protein in a549 alveolar epithelial cells: inhibition by methyl prednisolone.legionella pneumophila pneumonia often exacerbates acute lung injury (ali) and acute respiratory distress syndrome (ards). apoptosis of alveolar epithelial cells is considered to play an important role in the pathogenesis of ali and ards. in this study, we investigated the precise mechanism by which a549 alveolar epithelial cells induced by l. pneumophila undergo apoptosis. we also studied the effect of methyl prednisolone on apoptosis in these cells.200818447956
evaluation of three real-time pcr assays for detection of mycoplasma pneumoniae in an outbreak investigation.we compared the performances of three recently optimized real-time pcr assays derived from distinct genomic regions of mycoplasma pneumoniae during an outbreak. comprehensive evaluation established that a newly described toxin gene represents a superior target for detecting m. pneumoniae dna in clinical specimens, although use of multiple targets may increase testing confidence.200818614663
a dot/icm-translocated ankyrin protein of legionella pneumophila is required for intracellular proliferation within human macrophages and protozoa.the dot/icm type iv secretion system of legionella pneumophila translocates numerous bacterial effectors into the host cell and is essential for bacterial proliferation within macrophages and protozoa. we have recently shown that l. pneumophila strain aa100/130b harbours 11 genes encoding eukaryotic-like ankyrin (ank) proteins, a family of proteins involved in various essential eukaryotic cellular processes. in contrast to most dot/icm-exported substrates, which have little or no detectable role ...200818811729
development of real-time multiplex nucleic acid sequence-based amplification for detection of mycoplasma pneumoniae, chlamydophila pneumoniae, and legionella spp. in respiratory specimens.real-time multiplex isothermal nucleic acid sequence-based amplification (nasba) was developed to detect mycoplasma pneumoniae, chlamydophila pneumoniae, and legionella spp. in respiratory specimens using the nuclisens basic kit (biomérieux, boxtel, the netherlands). oligonucleotide primers were derived from the m. pneumoniae, c. pneumoniae, and legionella pneumophila 16s rrna. for real-time detection, molecular beacons were used. specificity was established on a panel of bacterial strains. the ...200818032625
development of real-time multiplex nucleic acid sequence-based amplification for detection of mycoplasma pneumoniae, chlamydophila pneumoniae, and legionella spp. in respiratory specimens.real-time multiplex isothermal nucleic acid sequence-based amplification (nasba) was developed to detect mycoplasma pneumoniae, chlamydophila pneumoniae, and legionella spp. in respiratory specimens using the nuclisens basic kit (biomérieux, boxtel, the netherlands). oligonucleotide primers were derived from the m. pneumoniae, c. pneumoniae, and legionella pneumophila 16s rrna. for real-time detection, molecular beacons were used. specificity was established on a panel of bacterial strains. the ...200818032625
an economical tandem multiplex real-time pcr technique for the detection of a comprehensive range of respiratory pathogens.this study used real-time pcr assays to screen small sample volumes for a comprehensive range of 35 respiratory pathogens. initial thermocycling was limited to 20 cycles to avoid competition for reagents, followed by a secondary real-time multiplex pcr. supplementary semi-nested human metapneumovirus and picornavirus pcr assays were required to complete the acute respiratory pathogen profile. potential pathogens were detected in 85 (70%) of pernasal aspirates collected from 121 children with acu ...200921994537
the legionella pneumophila replication vacuole: making a cosy niche inside host cells.the pathogenesis of legionella pneumophila is derived from its growth within lung macrophages after aerosols are inhaled from contaminated water sources. interest in this bacterium stems from its ability to manipulate host cell vesicular-trafficking pathways and establish a membrane-bound replication vacuole, making it a model for intravacuolar pathogens. establishment of the replication compartment requires a specialized translocation system that transports a large cadre of protein substrates a ...200919011659
the legionella pneumophila replication vacuole: making a cosy niche inside host cells.the pathogenesis of legionella pneumophila is derived from its growth within lung macrophages after aerosols are inhaled from contaminated water sources. interest in this bacterium stems from its ability to manipulate host cell vesicular-trafficking pathways and establish a membrane-bound replication vacuole, making it a model for intravacuolar pathogens. establishment of the replication compartment requires a specialized translocation system that transports a large cadre of protein substrates a ...200919011659
modulation of ubiquitin dynamics and suppression of dalis formation by the legionella pneumophila dot/icm system.legionella pneumophila is an intracellular pathogen that uses effector proteins translocated by the dot/icm type iv secretion system to modulate host cellular processes. here we investigate the dynamics of subcellular structures containing ubiquitin during l. pneumophila infection of phagocytic host cells. the dot/icm system mediated the formation of k48 and k63 poly-ubiquitin conjugates to proteins associated with l. pneumophila-containing vacuoles in macrophages and dendritic cells, suggesting ...200919016782
modulation of ubiquitin dynamics and suppression of dalis formation by the legionella pneumophila dot/icm system.legionella pneumophila is an intracellular pathogen that uses effector proteins translocated by the dot/icm type iv secretion system to modulate host cellular processes. here we investigate the dynamics of subcellular structures containing ubiquitin during l. pneumophila infection of phagocytic host cells. the dot/icm system mediated the formation of k48 and k63 poly-ubiquitin conjugates to proteins associated with l. pneumophila-containing vacuoles in macrophages and dendritic cells, suggesting ...200919016782
"my foot hurts": a flare of rheumatoid arthritis?a 56-year-old man with a history of rheumatoid arthritis presented with a 2-day history of worsening pain in his left foot. treatment with high-dose steroids was of no benefit, hence a diagnosis of septic arthritis was considered. however, the patient's condition deteriorated despite empirical antibiotic therapy. following persistent investigation, the cause was identified as a fastidious legionella longbeachae infection, and appropriate antibiotic therapy led to complete resolution of the sepsi ...200919351317
commercial potting soils as an alternative infection source of legionella pneumophila and other legionella species in switzerland.legionella spp. are pathogens that can cause legionnaires' disease in humans through inhalation of contaminated aerosols. the principal reservoir for these microorganisms is water, but legionella spp. have been isolated from composted vegetable and plant material, and from many potting mixes as well. in australia, there have been several cases of legionnaires' disease in which legionella longbeachae has been isolated from potting soils. in switzerland, the source of infection cannot always be id ...200919392903
experimental legionella longbeachae infection in intratracheally inoculated mice.this study established an experimental model of replicative legionella longbeachae infection in a/j mice. the animals were infected by intratracheal inoculation of 10(3)-10(9) c.f.u. l. longbeachae serogroup 1 (usa clinical isolates d4968, d4969 and d4973). the inocula of 10(9), 10(8), 10(7) and 10(6) c.f.u. of all tested l. longbeachae serogroup 1 isolates were lethal for a/j mice. inoculation of 10(5) c.f.u. l. longbeachae caused death in 90 % of the animals within 5 days, whilst inoculation o ...200919429747
potentially pathogenic bacteria in shower water and air of a stem cell transplant unit.potential pathogens from shower water and aerosolized shower mist (i.e., shower aerosol) have been suggested as an environmental source of infection for immunocompromised patients. to quantify the microbial load in shower water and aerosol samples, we used culture, microscopic, and quantitative pcr methods to investigate four shower stalls in a stem cell transplant unit at barnes-jewish hospital in st. louis, mo. we also tested membrane-integrated showerheads as a possible mitigation strategy. i ...200919581474
an unusual case of hospital-acquired infection: legionella longbeachae. 200919585301
an outbreak of pontiac fever due to legionella longbeachae serogroup 2 found in potting mix in a horticultural nursery in new zealand.previous outbreaks of pontiac fever have invariably been associated with water droplet spread of legionella spp. in january 2007 three workers from a horticultural nursery were admitted to hospital with non-pneumonic legionellosis. investigations showed that a working party of ten people had been exposed to aerosolized potting mix; nine of these workers met the case definition for pontiac fever. the presence of genetically indistinguishable legionella longbeachae serogroup 2 was demonstrated in ...201019781115
caenorhabditis is a metazoan host for legionella.we investigated whether nematodes contribute to the persistence, differentiation and amplification of legionella species in soil, an emerging source for legionnaires' disease. here we show that legionella spp. colonize the intestinal tracts of caenorhabditis nematodes leading to worm death. susceptibility to legionella is influenced by innate immune responses governed by the p38 mitogen-activated protein kinase and insulin/insulin growth factor-1 receptor signalling pathways. we also show that l ...201019863556
caenorhabditis is a metazoan host for legionella.we investigated whether nematodes contribute to the persistence, differentiation and amplification of legionella species in soil, an emerging source for legionnaires' disease. here we show that legionella spp. colonize the intestinal tracts of caenorhabditis nematodes leading to worm death. susceptibility to legionella is influenced by innate immune responses governed by the p38 mitogen-activated protein kinase and insulin/insulin growth factor-1 receptor signalling pathways. we also show that l ...201019863556
[community-acquired pneumonia caused by legionella longbeachae serogroup 1 in an immunocompetent patient]. 201019897280
legionnaires' disease caused by legionella longbeachae and legionella pneumophila: comparison of clinical features, host-related risk factors, and outcomes.legionnaires' disease remains an important cause of mortality and morbidity worldwide. disease caused by legionella pneumophila has been extensively studied, and its clinical characteristics have been well described. there is, however, little information on disease caused by legionella longbeachae, despite its importance in some countries. we undertook a retrospective review of culture-positive cases of legionnaires' disease in the canterbury region of new zealand over 10 years, in order to comp ...201019930271
temporal and spatial trigger of post-exponential virulence-associated regulatory cascades by legionella pneumophila after bacterial escape into the host cell cytosol.during late stages of infection and prior to lysis of the infected macrophages or amoeba, the legionella pneumophila-containing phagosome becomes disrupted, followed by bacterial escape into the host cell cytosol, where the last few rounds of bacterial proliferation occur prior to lysis of the plasma membrane. this coincides with growth transition into the post-exponential (pe) phase, which is controlled by regulatory cascades including rpos and the leta/s two-component regulator. whether the te ...201019958381
temporal and spatial trigger of post-exponential virulence-associated regulatory cascades by legionella pneumophila after bacterial escape into the host cell cytosol.during late stages of infection and prior to lysis of the infected macrophages or amoeba, the legionella pneumophila-containing phagosome becomes disrupted, followed by bacterial escape into the host cell cytosol, where the last few rounds of bacterial proliferation occur prior to lysis of the plasma membrane. this coincides with growth transition into the post-exponential (pe) phase, which is controlled by regulatory cascades including rpos and the leta/s two-component regulator. whether the te ...201019958381
virulence factors encoded by legionella longbeachae identified on the basis of the genome sequence analysis of clinical isolate d-4968.legionella longbeachae causes most cases of legionellosis in australia and may be underreported worldwide due to the lack of l. longbeachae-specific diagnostic tests. l. longbeachae displays distinctive differences in intracellular trafficking, caspase 1 activation, and infection in mouse models compared to legionella pneumophila, yet these two species have indistinguishable clinical presentations in humans. unlike other legionellae, which inhabit freshwater systems, l. longbeachae is found pred ...201020008069
duplex real-time reverse transcriptase pcr assays for rapid detection and identification of pandemic (h1n1) 2009 and seasonal influenza a/h1, a/h3, and b viruses.reports of a novel influenza virus type a (h1n1), now designated by the world health organization as pandemic (h1n1) 2009, emerged from the united states and mexico in april 2009. the management of the pandemic in australia required rapid and reliable testing of large numbers of specimens for the novel influenza strain and differentiation from seasonal influenza strains. a real-time reverse transcriptase pcr (rt-pcr) assay for the detection of pandemic (h1n1) 2009 was designed and used with exis ...201020071557
update on legionnaires' disease: pathogenesis, epidemiology, detection and control.legionellosis or legionnaires' disease is an emerging and often-fatal form of pneumonia that is most severe in elderly and immunocompromised people, an ever-increasing risk group for infection. in recent years, the genomics of legionella spp. has significantly increased our knowledge of the pathogenesis of this disease by providing new insights into the evolution and genetic and physiological basis of legionella-host interactions. the seventh international conference on legionella, legionella 20 ...201020149105
analysis of the legionella longbeachae genome and transcriptome uncovers unique strategies to cause legionnaires' disease.legionella pneumophila and l. longbeachae are two species of a large genus of bacteria that are ubiquitous in nature. l. pneumophila is mainly found in natural and artificial water circuits while l. longbeachae is mainly present in soil. under the appropriate conditions both species are human pathogens, capable of causing a severe form of pneumonia termed legionnaires' disease. here we report the sequencing and analysis of four l. longbeachae genomes, one complete genome sequence of l. longbeach ...201020174605
a cluster of legionnaires' disease caused by legionella longbeachae linked to potting compost in scotland, 2008-2009.three cases of legionnaires disease caused by legionella longbeachae sg 1 associated with potting compost have been reported in scotland between 2008 and 2009. the exact method of transmission is still not fully understood as legionnaires disease is thought to be acquired by droplet inhalation. the linked cases associated with compost exposure call for an introduction of compost labelling, as is already in place in other countries where l. longbeachae outbreaks have been reported.201020197024
exploitation of conserved eukaryotic host cell farnesylation machinery by an f-box effector of legionella pneumophila.farnesylation involves covalent linkage of eukaryotic proteins to a lipid moiety to anchor them into membranes, which is essential for the biological function of ras and other proteins. a large cadre of bacterial effectors is injected into host cells by intravacuolar pathogens through elaborate type iii-vii translocation machineries, and many of these effectors are incorporated into the pathogen-containing vacuolar membrane by unknown mechanisms. the dot/icm type iv secretion system of legionell ...201020660614
distribution of legionella species from environmental water sources of public facilities and genetic diversity of l. pneumophila serogroup 1 in south korea.a total of 560 legionella species were isolated from environmental water sources from public facilities from june to september 2008 throughout south korea. the distribution of legionella isolates was investigated according to geographical region, facility type, and sample type. the genetic diversity of 104 isolates of legionella pneumophila serogroup 1 (sg 1) was analyzed by sequence-based typing (sbt). l. pneumophila was distributed broadly throughout korea, accounting for 85.0% of the isolates ...201020693456
legionella pneumophila strain 130b possesses a unique combination of type iv secretion systems and novel dot/icm secretion system effector proteins.legionella pneumophila is a ubiquitous inhabitant of environmental water reservoirs. the bacteria infect a wide variety of protozoa and, after accidental inhalation, human alveolar macrophages, which can lead to severe pneumonia. the capability to thrive in phagocytic hosts is dependent on the dot/icm type iv secretion system (t4ss), which translocates multiple effector proteins into the host cell. in this study, we determined the draft genome sequence of l. pneumophila strain 130b (wadsworth). ...201020833813
dioxygenases in burkholderia ambifaria and yersinia pestis that hydroxylate the outer kdo unit of lipopolysaccharide.several gram-negative pathogens, including yersinia pestis, burkholderia cepacia, and acinetobacter haemolyticus, synthesize an isosteric analog of 3-deoxy-d-manno-oct-2-ulosonic acid (kdo), known as d-glycero-d-talo-oct-2-ulosonic acid (ko), in which the axial hydrogen atom at the kdo 3-position is replaced with oh. here we report a unique kdo 3-hydroxylase (kdoo) from burkholderia ambifaria and yersinia pestis, encoded by the bamb_0774 (bakdoo) and the y1812 (ypkdoo) genes, respectively. when ...201021178073
specific real-time pcr for simultaneous detection and identification of legionella pneumophila serogroup 1 in water and clinical samples.legionella pneumophila, a bacterium that replicates within aquatic amoebae and persists in the environment as a free-living microbe, is the causative agent of legionnaires' disease. among the many legionella species described, l. pneumophila is associated with 90% of human disease, and within the 15 serogroups (sg), l. pneumophila sg1 causes more than 84% of legionnaires' disease worldwide. thus, rapid and specific identification of l. pneumophila sg1 is of the utmost importance for evaluation o ...201021193672
specific real-time pcr for simultaneous detection and identification of legionella pneumophila serogroup 1 in water and clinical samples.legionella pneumophila, a bacterium that replicates within aquatic amoebae and persists in the environment as a free-living microbe, is the causative agent of legionnaires' disease. among the many legionella species described, l. pneumophila is associated with 90% of human disease, and within the 15 serogroups (sg), l. pneumophila sg1 causes more than 84% of legionnaires' disease worldwide. thus, rapid and specific identification of l. pneumophila sg1 is of the utmost importance for evaluation o ...201021193672
the aspartate-semialdehyde dehydrogenase of edwardsiella ictaluri and its use as balanced-lethal system in fish vaccinology.asda mutants of gram-negative bacteria have an obligate requirement for diaminopimelic acid (dap), which is an essential constituent of the peptidoglycan layer of the cell wall of these organisms. in environments deprived of dap, i.e., animal tissues, they will undergo lysis. deletion of the asda gene has previously been exploited to develop antibiotic-sensitive strains of live attenuated recombinant bacterial vaccines. introduction of an asd(+) plasmid into a δasda mutant makes the bacterial st ...201021209920
dual detection of legionella pneumophila and legionella species by real-time pcr targeting the 23s-5s rrna gene spacer region.although the majority of cases of legionnaires' disease (ld) are caused by legionella pneumophila, an increasing number of other legionella species have been reported to cause human disease. there are no clinical presentations unique to ld and hence accurate laboratory tests are required for early diagnosis. therefore, we designed a real-time pcr assay that targets the 23s-5s rrna intergenic spacer region (23s-5s pcr) and allows for detection of all legionella species and discrimination of l. pn ...201019438641
exploitation of host polyubiquitination machinery through molecular mimicry by eukaryotic-like bacterial f-box effectors.microbial pathogens have evolved exquisite mechanisms to interfere and intercept host biological processes, often through molecular mimicry of specific host proteins. ubiquitination is a highly conserved eukaryotic post-translational modification essential in determining protein fate, and is often hijacked by pathogenic bacteria. the conserved skp1/cul1/f-box (scf) e3 ubiquitin ligase complex plays a key role in ubiquitination of proteins in eukaryotic cells. the f-box protein component of the s ...201021687758
circadian clock proteins in prokaryotes: hidden rhythms?circadian clock genes are vital features of eukaryotes that have evolved such that organisms can adapt to our planet's rotation in order to anticipate the coming day or night as well as unfavorable seasons. this circadian clock uses oscillation as a timekeeping element. however, circadian clock mechanisms exist also in prokaryotes. the circadian clock of cyanobacteria is well studied. it is regulated by a cluster of three genes: kaia, kaib, and kaic. in this review, we will discuss the circadian ...201021687756
predicted class-i aminoacyl trna synthetase-like proteins in non-ribosomal peptide synthesis.recent studies point to a great diversity of non-ribosomal peptide synthesis systems with major roles in amino acid and co-factor biosynthesis, secondary metabolism, and post-translational modifications of proteins by peptide tags. the least studied of these systems are those utilizing trnas or aminoacyl-trna synthetases (aatrs) in non-ribosomal peptide ligation.201020678224
Legionella longbeachae serogroup 1 infections linked to Potting Compost.Four cases of legionellosis caused by Legionella longbeachae Serogroup (Sg) 1 were identified in Scotland from 2008 to 2010. All cases had exposure to commercially manufactured growing media or potting soils, commonly known as multi-purpose compost (MPC), in greenhouse conditions, prior to disease onset. Two cases had been using the same brand of MPC, however the clinical isolates were distinct genotypically by amplified fragment length polymorphism (AFLP) analysis, but an indistinguishable AFLP ...201121940651
The N-Acylneuraminate Cytidyltransferase Gene, neuA, Is Heterogenous in Legionella pneumophila Strains but Can Be Used as a Marker for Epidemiological Typing in the Consensus Sequence-Based Typing Scheme.Sequence-based typing (SBT) is the internationally recognized standard method for genotyping Legionella pneumophila. To date all strains of serogroup 1 (SG1) and some of SGs 2 to 14 yield a seven-allele profile and can be assigned a sequence type (ST). However, for some strains belonging to SGs 2 to 14, the targeted region of the neuA gene could not be amplified using the published standard primers. We determined the DNA sequence of a neuA gene homolog located in the lipopolysaccharide synthesis ...201121956982
identification of legionella pneumophila serogroups and other legionella species by mip gene sequencing.the virulence factor known as the macrophage infectivity potentiator (mip) is responsible for the intracellular survival of legionella species. in this study, we investigated the potential of the mip gene sequence to differentiate isolates of different species of legionella and different serogroups of legionella pneumophila. we used 35 clinical l. pneumophila isolates and one clinical isolate each of legionella micdadei, legionella longbeachae, and legionella dumoffii (collected from hospitals a ...201122015397
the occurrence of legionella species other than legionella pneumophila in clinical and environmental samples in denmark identified by mip gene sequencing and matrix-assisted laser desorption ionization time-of-flight mass spectrometry.clin microbiol infect abstract: in denmark, several laboratories use pcr as a routine diagnostic method for legionnaires' disease, and almost all pcr-positive samples are investigated by culture. from 1993 to 2010, isolates of legionella species other than legionella pneumophila were obtained from respiratory samples from 33 patients, and from 1997 to 2010, 42 isolates of legionella non-pneumophila species were obtained and saved from water samples from 39 different sites in denmark. macrophage ...201122070605
acrb trimer stability and efflux activity, insight from mutagenesis studies.the multidrug transporter acrb in escherichia coli exists and functions as a homo-trimer. the assembly process of obligate membrane protein oligomers, including acrb, remains poorly understood. in a previous study, we have shown that individual acrb subunit is capable of folding independently, suggesting that trimerization of acrb follows a three-stage pathway in which monomers first fold, and then assemble. here we destabilized the acrb trimer through mutating a single pro (p223) in the protrud ...201122163011
extensive recombination events and horizontal gene transfer shaped the legionella pneumophila genomes.legionella pneumophila is an intracellular pathogen of environmental protozoa. when humans inhale contaminated aerosols this bacterium may cause a severe pneumonia called legionnaires' disease. despite the abundance of dozens of legionella species in aquatic reservoirs, the vast majority of human disease is caused by a single serogroup (sg) of a single species, namely l. pneumophila sg1. to get further insights into genome dynamics and evolution of sg1 strains, we sequenced strains lorraine and ...201122044686
Comparative and functional genomics of legionella identified eukaryotic like proteins as key players in host-pathogen interactions.Although best known for its ability to cause severe pneumonia in people whose immune defenses are weakened, Legionella pneumophila and Legionella longbeachae are two species of a large genus of bacteria that are ubiquitous in nature, where they parasitize protozoa. Adaptation to the host environment and exploitation of host cell functions are critical for the success of these intracellular pathogens. The establishment and publication of the complete genome sequences of L. pneumophila and L. long ...201122059087
the major facilitator superfamily-type protein lbtc promotes the utilization of the legiobactin siderophore by legionella pneumophila.the gram-negative bacterium legionella pneumophila elaborates the siderophore legiobactin. we previously showed that cytoplasmic lbta helps mediate legiobactin synthesis, inner membrane lbtb promotes export of legiobactin, and outer membrane lbtu acts as the ferrisiderophore receptor. rt-pcr analyses now identified lbtc as an iron-repressed gene that is the final gene in an operon containing lbta and lbtb. in silico analysis predicted that lbtc is an inner membrane protein that belongs to the ...201122160401
[Distribution and diversity of Legionella spp. in Lake Taihu in the winter].The Legionella spp. are ubiquitous in aquatic environment and could cause certain risks on human health. In order to investigate the distribution and diversity of Legionella spp. in Lake Taihu during winter time, water samples were collected from 32 sites of the whole lake in February 2010. The presence of Legionella spp. was screened by nested-PCR and their phylogenetic diversity was determined by denaturing gradient gel electrophorese (DGGE) and sequencing analysis of excised DGGE bands. The L ...201121922841
effector glycosyltransferases in legionella.legionella causes severe pneumonia in humans. the pathogen produces an array of effectors, which interfere with host cell functions. among them are the glucosyltransferases lgt1, lgt2 and lgt3 from l. pneumophila. lgt1 and lgt2 are produced predominately in the post-exponential phase of bacterial growth, while synthesis of lgt3 is induced mainly in the lag-phase before intracellular replication of bacteria starts. lgt glucosyltransferases are structurally similar to clostridial glucosylating tox ...201121833323
the nlrc4 inflammasome contributes to restriction of pulmonary infection by flagellated legionella spp. that trigger pyroptosis.the nlrc4 inflammasome is triggered in response to contamination of the host cell cytoplasm with bacterial flagellin, which induces pyroptosis, a form of cell death that accounts for restriction of bacterial infections. although induction of pyroptosis has been extensively investigated in response to salmonella typhimurium and legionella pneumophila, little is known regarding the role of the inflammasome for restriction of non-pneumophila legionella species. here, we used five species of the leg ...201121687424
annotation of protein domains reveals remarkable conservation in the functional make up of proteomes across superkingdoms.the functional repertoire of a cell is largely embodied in its proteome, the collection of proteins encoded in the genome of an organism. the molecular functions of proteins are the direct consequence of their structure and structure can be inferred from sequence using hidden markov models of structural recognition. here we analyze the functional annotation of protein domain structures in almost a thousand sequenced genomes, exploring the functional and structural diversity of proteomes. we find ...201124710297
legionella longbeachae and legionellosis.reported cases of legionellosis attributable to legionella longbeachae infection have increased worldwide. in australia and new zealand, l. longbeachae has been a known cause of legionellosis since the late 1980s. all cases for which a source was confirmed were associated with potting mixes and composts. unlike the situation with other legionella spp., l. longbeachae-contaminated water systems in the built environment that cause disease have not been reported. spatially and temporally linked out ...201121470444
pcr methods for the rapid detection and identification of four pathogenic legionella spp. and two legionella pneumophila subspecies based on the gene amplification of gyrb.a total of 25 gyrb gene sequences from 20 legionella pneumophila subsp. pneumophila strains and five l. pneumophila subsp. fraseri strains were obtained and analyzed, and a multiplex pcr for the simultaneous detection of legionella bozemanae, legionella longbeachae, legionella micdadei and legioenella pneumophila, and two single pcrs for the differentiation of l. pneumophila subsp. pneumophila and l. pneumophila subsp. fraseri were established. the multiplex pcr method was shown to be highly spe ...201121626022
calpain chronicle--an enzyme family under multidisciplinary characterization.calpain is an intracellular ca2+-dependent cysteine protease (ec 3.4.22.17; clan ca, family c02) discovered in 1964. it was also called canp (ca2+-activated neutral protease) as well as casf, cdp, kaf, etc. until 1990. calpains are found in almost all eukaryotes and a few bacteria, but not in archaebacteria. calpains have a limited proteolytic activity, and function to transform or modulate their substrates' structures and activities; they are therefore called, "modulator proteases." in the huma ...201121670566
the atypical two-component sensor kinase lpl0330 from legionella pneumophila controls the bifunctional diguanylate cyclase-phosphodiesterase lpl0329 to modulate c-di-gmp synthesis.a significant part of bacterial two-component system response regulators contain effector domains predicted to be involved in metabolism of c-di-gmp, a second messenger which plays a key role in many physiological processes. intracellular level of c-di-gmp is controlled by diguanylate cyclases (dgcs) and phosphodiesterases (pdes) activities associated with ggdef and eal domains, respectively. the legionella pneumophila lens genome displays 22 ggdef/eal domain-encoding genes. one of them, lpl0329 ...201121757706
type ivb secretion systems of legionella and other gram-negative bacteria.type iv secretion systems (t4sss) play a central role in the pathogenicity of many important pathogens, including agrobacterium tumefaciens, helicobacter pylori, and legionella pneumophila. the t4sss are related to bacterial conjugation systems, and are classified into two subgroups, type iva (t4ass) and type ivb (t4bss). the t4bss, which is closely related to conjugation systems of inci plasmids, was originally found in human pathogen l. pneumophila; pathogenesis by l. pneumophila infection req ...201121743810
in vitro antibacterial activity of modithromycin, a novel 6,11-bridged bicyclolide, against respiratory pathogens, including macrolide-resistant gram-positive cocci.the in vitro activities of modithromycin against gram-positive and -negative respiratory pathogens, including macrolide-resistant cocci with different resistance mechanisms, were compared with those of other macrolide and ketolide agents. mics were determined by the broth microdilution method. all 595 test strains used in this study were isolated from japanese medical facilities. the erm (ribosome methylase) and/or mef (efflux pump) gene, which correlated with resistance to erythromycin as well ...201121220534
legionella pneumophila lbtu acts as a novel, tonb-independent receptor for the legiobactin siderophore.gram-negative legionella pneumophila produces a siderophore (legiobactin) that promotes lung infection. we previously determined that lbta and lbtb are required for the synthesis and secretion of legiobactin. dna sequence and reverse transcription-pcr (rt-pcr) analyses now reveal the presence of an iron-repressed gene (lbtu) directly upstream of the lbtab-containing operon. in silico analysis predicted that lbtu is an outer membrane protein consisting of a 16-stranded transmembrane ß-barrel, mul ...201121278293
lcl of legionella pneumophila is an immunogenic gag binding adhesin that promotes interactions with lung epithelial cells and plays a crucial role in biofilm formation.legionellosis is mostly caused by legionella pneumophila and is defined by a severe respiratory illness with a case fatality rate ranging from 5 to 80%. in vitro and in vivo, interactions of l. pneumophila with lung epithelial cells are mediated by the sulfated glycosaminoglycans (gags) of the host extracellular matrix. in this study, we have identified several legionella heparin binding proteins. we have shown that one of these proteins, designated lcl, is a polymorphic adhesin of l. pneumophil ...201121422183
sequence, structure and functional diversity of pd-(d/e)xk phosphodiesterase superfamily.proteins belonging to pd-(d/e)xk phosphodiesterases constitute a functionally diverse superfamily with representatives involved in replication, restriction, dna repair and trna-intron splicing. their malfunction in humans triggers severe diseases, such as fanconi anemia and xeroderma pigmentosum. to date there have been several attempts to identify and classify new pd-(d/e)kk phosphodiesterases using remote homology detection methods. such efforts are complicated, because the superfamily exhibit ...201222638584
legionella pneumophila secretes a mitochondrial carrier protein during infection.the mitochondrial carrier family (mcf) is a signature group of integral membrane proteins that transport metabolites across the mitochondrial inner membrane in eukaryotes. mcf proteins are characterized by six transmembrane segments that assemble to form a highly-selective channel for metabolite transport. we discovered a novel mcf member, termed legionellanucleotide carrier protein (lncp), encoded in the genome of legionella pneumophila, the causative agent of legionnaire's disease. lncp was se ...201222241989
legionella longbeachae and endocarditis.we report a case of infectious endocarditis attributable to legionella longbeachae. l. longbeachae is usually associated with lung infections. it is commonly found in composted waste wood products. l. longbeachae should be regarded as an agent of infectious endocarditis, notably in the context of gardening involving handling of potting soils.201222261182
two cases of severe pneumonia after the 2011 great east japan earthquake.in 2011, during the great east japan earthquake and tsunami, 90% of victims died from drowning. we report on two tsunami survivors with severe pneumonia potentially caused by legionella pneumophila. both victims aspirated a large quantity of contaminated water; sand, mud and a variety of microbes were thought to have entered into their lower respiratory tracts. one patient had a mycotic intracranial aneurysm; the other patient had co-infections with several organisms, including scedosporium spec ...201223908944
identification of acquired antimicrobial resistance genes.identification of antimicrobial resistance genes is important for understanding the underlying mechanisms and the epidemiology of antimicrobial resistance. as the costs of whole-genome sequencing (wgs) continue to decline, it becomes increasingly available in routine diagnostic laboratories and is anticipated to substitute traditional methods for resistance gene identification. thus, the current challenge is to extract the relevant information from the large amount of generated data.201222782487
lateral gene exchanges shape the genomes of amoeba-resisting microorganisms.based on darwin's concept of the tree of life, vertical inheritance was thought to be dominant, and mutations, deletions, and duplication were streaming the genomes of living organisms. in the current genomic era, increasing data indicated that both vertical and lateral gene inheritance interact in space and time to trigger genome evolution, particularly among microorganisms sharing a given ecological niche. as a paradigm to their diversity and their survival in a variety of cell types, intracel ...201222919697
structural and functional insights from the metagenome of an acidic hot spring microbial planktonic community in the colombian andes.a taxonomic and annotated functional description of microbial life was deduced from 53 mb of metagenomic sequence retrieved from a planktonic fraction of the neotropical high andean (3,973 meters above sea level) acidic hot spring el coquito (ec). a classification of unassembled metagenomic reads using different databases showed a high proportion of gammaproteobacteria and alphaproteobacteria (in total read affiliation), and through taxonomic affiliation of 16s rrna gene fragments we observed th ...201223251687
detection of legionella bozemanae, a new cause of septic arthritis, by pcr followed by specific culture.legionella bozemanae is a rare isolate in clinical specimens. we describe a case of joint infection due to l. bozemanae in an immunocompromised patient with dermatomyositis. without the use of pcr screening or culture on specialized medium, the organism would not have been detected.201223052316
legionnaires' disease caused by legionella londiniensis.legionella londiniensis has been isolated from aqueous environments. however, to our knowledge, this organism has never been isolated from clinical specimens. a case of legionnaires' disease in a hematopoietic stem cell transplant recipient caused by this organism is described, which confirms that l. londiniensis can be an opportunistic pathogen.201223052303
genome analysis of legionella pneumophila strains using a mixed-genome microarray.legionella, the causative agent for legionnaires' disease, is ubiquitous in both natural and man-made aquatic environments. the distribution of legionella genotypes within clinical strains is significantly different from that found in environmental strains. developing novel genotypic methods that offer the ability to distinguish clinical from environmental strains could help to focus on more relevant (virulent) legionella species in control efforts. mixed-genome microarray data can be used to pe ...201223094048
bronchiolitis outbreak caused by respiratory syncytial virus in southwest bangladesh, 2010.during july 2010, newspapers reported a respiratory disease outbreak in southwestern bangladesh resulting in the admission of children to a secondary care hospital. we investigated this outbreak to determine the etiology and explore possible risk factors.201222938872
structural basis for substrate recognition by a unique legionella phosphoinositide phosphatase.legionella pneumophila is an opportunistic intracellular pathogen that causes sporadic and epidemic cases of legionnaires' disease. emerging data suggest that legionella infection involves the subversion of host phosphoinositide (pi) metabolism. however, how this bacterium actively manipulates pi lipids to benefit its infection is still an enigma. here, we report that the l. pneumophila virulence factor sidf is a phosphatidylinositol polyphosphate 3-phosphatase that specifically hydrolyzes the d ...201222872863
live attenuated s. typhimurium vaccine with improved safety in immuno-compromised mice.live attenuated vaccines are of great value for preventing infectious diseases. they represent a delicate compromise between sufficient colonization-mediated adaptive immunity and minimizing the risk for infection by the vaccine strain itself. immune defects can predispose to vaccine strain infections. it has remained unclear whether vaccine safety could be improved via mutations attenuating a vaccine in immune-deficient individuals without compromising the vaccine's performance in the normal ho ...201223029007
survey of legionella species found in thai soil.members of the gram-negative genus legionella are typically found in freshwater environments, with the exception of l. longbeachae, which is present in composts and potting mixes. when contaminated aerosols are inhaled, legionellosis may result, typically as either the more serious pneumonia legionnaires' disease or the less severe flu-like illness pontiac fever. it is presumed that all species of the genus legionella are capable of causing disease in humans. as a followup to a prior clinical st ...201222287969
metal transport across biomembranes: emerging models for a distinct chemistry.transition metals are essential components of important biomolecules, and their homeostasis is central to many life processes. transmembrane transporters are key elements controlling the distribution of metals in various compartments. however, due to their chemical properties, transition elements require transporters with different structural-functional characteristics from those of alkali and alkali earth ions. emerging structural information and functional studies have revealed distinctive fea ...201222389499
severe legionnaire's disease caused by legionella longbeachae in a long-term renal transplant patient: the importance of safe living strategies after transplantation.legionella species are intracellular gram-negative bacilli that require specific culture media for growth. transplant recipients with impaired cellular immunity are at particular risk for infection with this pathogen. most human disease is caused by legionella pneumophila; disease caused by non-l. pneumophila species is reported mainly in immunosuppressed patients with the exception of legionella longbeachae. l. longbeachae is a common cause of legionnaires' disease in australia and new zealand, ...201222686947
[molecular identification, phylogenic and virulence analysis of a legionella strain isolated from aquatic environment].cd-1 was isolated from aquatic environment, which grew with strict l-cysteine dependence. in this study, we applied molecular methods to identify cd-1, and animal test to understand its virulence.201222455131
cluster of legionnaires disease cases caused by legionella longbeachae serogroup 1, scotland, august to september 2013.we report six confirmed cases of legionnaires' disease in scotland caused by legionella longbeachae serogroup 1, identified over a four-week period in august–september 2013. all cases required admission to hospital intensive care facilities. all cases were amateur gardeners with frequent exposure to horticultural growing media throughout their incubation period. l. longbeachae was identified in five samples of growing media linked to five cases. product tracing did not identify a common product ...201324342515
prediction of the origin of french legionella pneumophila strains using a mixed-genome microarray.legionella is a water and soil bacterium that can infect humans, causing a pneumonia known as legionnaires' disease. the pneumonia is almost exclusively caused by the species l. pneumophila, of which serogroup 1 is responsible for 90% of patients. within serogroup 1, large differences in prevalence in clinical isolates have been described. a recent study, using a dutch legionella strain collection, identified five virulence associated markers. in our study, we verify whether these five dutch mar ...201323815549
osteomyelitis of the patella caused by legionella anisa.a 51-year-old man with a history of stage iv angioimmunoblastic t-cell lymphoma was diagnosed with osteomyelitis of the patella. legionella anisa was identified by 16s rrna gene sequencing and culture. the patient had pneumonia 2 months prior to this osteomyelitis episode. l. anisa was retrospectively detected in his lung tissue by 16s rrna gene sequencing and was considered the source of the l. anisa that caused his patella osteomyelitis.201323761141
draft genome sequence of the male-killing wolbachia strain wbol1 reveals recent horizontal gene transfers from diverse sources.the endosymbiont wolbachia pipientis causes diverse and sometimes dramatic phenotypes in its invertebrate hosts. four wolbachia strains sequenced to date indicate that the constitution of the genome is dynamic, but these strains are quite divergent and do not allow resolution of genome diversification over shorter time periods. we have sequenced the genome of the strain wbol1-b, found in the butterfly hypolimnas bolina, which kills the male offspring of infected hosts during embyronic developmen ...201323324387
comparison of the legionella pneumophila population structure as determined by sequence-based typing and whole genome sequencing.legionella pneumophila is an opportunistic pathogen of humans where the source of infection is usually from contaminated man-made water systems. when an outbreak of legionnaires' disease caused by l. pneumophila occurs, it is necessary to discover the source of infection. a seven allele sequence-based typing scheme (sbt) has been very successful in providing the means to attribute outbreaks of l. pneumophila to a particular source or sources. particular sequence types described by this scheme ar ...201324364868
development of a dna microarray method for detection and identification of all 15 distinct o-antigen forms of legionella pneumophila.legionella is ubiquitous in many environments. at least 50 species and 70 serogroups of the gram-negative bacterium have been identified. of the 50 species, 20 are pathogenic, and legionella pneumophila is responsible for the great majority (approximately 90%) of the legionnaires' disease cases that occur. furthermore, of the 15 l. pneumophila serogroups identified, o1 alone causes more than 84% of the legionnaires' disease cases that occur worldwide. rapid and reliable assays for the detection ...201323974134
identification and functional characterization of k(+) transporters encoded by legionella pneumophila kup genes.legionnaires' disease is an emerging, severe, pneumonia-like illness caused by the gram-negative intracellular bacteria legionella pneumophila, which are able to infect and replicate intracellularly in macrophages. little is known regarding the mechanisms used by intracellular l. pneumophila for the acquisition of specific nutrients that are essential for bacterial replication. here, we investigate three l. pneumophila genes with high similarity to the escherichia coli k(+) transporters. these t ...201323848378
identification and structural characterization of a legionella phosphoinositide phosphatase.bacterial pathogen legionella pneumophila is the causative agent of legionnaires' disease, which is associated with intracellular replication of the bacteria in macrophages of human innate immune system. recent studies indicate that pathogenic bacteria can subvert host cell phosphoinositide (pi) metabolism by translocated virulence effectors. however, in which manner legionella actively exploits pi lipids to benefit its infection is not well characterized. here we report that l. pneumophila enco ...201323843460
multiple legionella pneumophila type ii secretion substrates, including a novel protein, contribute to differential infection of the amoebae acanthamoeba castellanii, hartmannella vermiformis, and naegleria lovaniensis.type ii protein secretion (t2s) by legionella pneumophila is required for intracellular infection of host cells, including macrophages and the amoebae acanthamoeba castellanii and hartmannella vermiformis. previous proteomic analysis revealed that t2s by l. pneumophila 130b mediates the export of >25 proteins, including several that appeared to be novel. following confirmation that they are unlike known proteins, t2s substrates ntta, nttb, and legp were targeted for mutation. ntta mutants were i ...201323429532
regulation, integrase-dependent excision, and horizontal transfer of genomic islands in legionella pneumophila.legionella pneumophila is a gram-negative freshwater agent which multiplies in specialized nutrient-rich vacuoles of amoebae. when replicating in human alveolar macrophages, legionella can cause legionnaires' disease. recently, we identified a new type of conjugation/type iva secretion system (t4ass) in l. pneumophila corby (named trb-tra). analogous versions of trb-tra are localized on the genomic islands trb-1 and trb-2. both can exist as an episomal circular form, and trb-1 can be transferred ...201323354744
high prevalence, genetic diversity and intracellular growth ability of legionella in hot spring environments.legionella is the causative agent of legionnaires' disease, and hot springs are a major source of outbreaks of this disease. it is important from a public health perspective to survey hot spring environments for the presence of legionella.201323527075
computational modeling and experimental validation of the legionella and coxiella virulence-related type-ivb secretion signal.legionella and coxiella are intracellular pathogens that use the virulence-related icm/dot type-ivb secretion system to translocate effector proteins into host cells during infection. these effectors were previously shown to contain a c-terminal secretion signal required for their translocation. in this research, we implemented a hidden semi-markov model to characterize the amino acid composition of the signal, thus providing a comprehensive computational model for the secretion signal. this mod ...201323382224
identification of legionella spp. in environmental water samples by scanvit-legionella™ method in spain.rapid and more sensitive methods for the detection and quantification of viable legionella cells have been developed. in this paper, a comparative analysis of environmental water samples using the scanvit-legionella™ method and the traditional "gold standard" method of culturing is realised indicating the usefulness of the scanvit method. the scanvit-legionella™ method was performed on environmental water samples from different locations of huesca region (spain). legionella micro-colonies should ...201324426100
molecular diversity and high virulence of legionella pneumophila strains isolated from biofilms developed within a warm spring of a thermal spa.several cases of legionellosis have been diagnosed in the same french thermal spa in 1986, 1994 and 1997. l. pneumophila serogroup 1 (lp1) strains have been isolated from several patients, but the source of contamination was not identified despite the presence of different lp1 in water samples of the three natural springs feeding the spa at this period.201323350929
evidence of the presence of a functional dot/icm type iv-b secretion system in the fish bacterial pathogen piscirickettsia salmonis.piscirickettsia salmonis is a fish bacterial pathogen that has severely challenged the sustainability of the chilean salmon industry since its appearance in 1989. as this gram-negative bacterium has been poorly characterized, relevant aspects of its life cycle, virulence and pathogenesis must be identified in order to properly design prophylactic procedures. this report provides evidence of the functional presence in p. salmonis of four genes homologous to those described for dot/icm type iv sec ...201323383004
genome dynamics in legionella: the basis of versatility and adaptation to intracellular replication.legionella pneumophila is a bacterial pathogen present in aquatic environments that can cause a severe pneumonia called legionnaires' disease. soon after its recognition, it was shown that legionella replicates inside amoeba, suggesting that bacteria replicating in environmental protozoa are able to exploit conserved signaling pathways in human phagocytic cells. comparative, evolutionary, and functional genomics suggests that the legionella-amoeba interaction has shaped this pathogen more than p ...201323732852
the dot/icm effector sdha is necessary for virulence of legionella pneumophila in galleria mellonella and a/j mice.legionella pneumophila is an intracellular bacterium that resides within amoebae and macrophages in a specialized compartment termed the legionella-containing vacuole (lcv). as well as providing an intracellular niche for replication, the lcv helps to prevent the release of bacterial components into the cytoplasm. recognition of these components as danger signals by the host activates immune responses leading to clearance of the bacterium. here, we examined the role of two important virulence fa ...201323649096
rapid pcr detection of mycoplasma hominis, ureaplasma urealyticum, and ureaplasma parvum.objective. we compared laboratory developed real-time pcr assays for detection of mycoplasma hominis and for detection and differentiation of ureaplasma urealyticum and parvum to culture using genitourinary specimens submitted for m. hominis and ureaplasma culture. methods. 283 genitourinary specimens received in the clinical bacteriology laboratory for m. hominis and ureaplasma species culture were evaluated. nucleic acids were extracted using the total nucleic acid kit on the magna pure 2.0. 5 ...201326904723
the legionella pneumophila dot/icm-secreted effector plcc/cegc1 together with plca and plcb promotes virulence and belongs to a novel zinc metallophospholipase c family present in bacteria and fungi.legionella pneumophila is a water-borne bacterium that causes pneumonia in humans. plca and plcb are two previously defined l. pneumophila proteins with homology to the phosphatidylcholine-specific phospholipase c (pc-plc) of pseudomonas fluorescens. additionally, we found that lpg0012 shows similarity to plcs and has been shown to be a dot/icm-injected effector, cegc1, which is designated here as plcc. it remained unclear, however, whether these l. pneumophila proteins exhibit plc activity. plc ...201323457299
intra-amoeba multiplication induces chemotaxis and biofilm colonization and formation for legionella.legionella pneumophila, a facultative intracellular bacterium, is the causative agent of legionellosis. in the environment this pathogenic bacterium colonizes the biofilms as well as amoebae, which provide a rich environment for the replication of legionella. when seeded on pre-formed biofilms, l. pneumophila was able to establish and survive and was only found at the surface of the biofilms. different phenotypes were observed when the l. pneumophila, used to implement pre-formed biofilms or to ...201324205008
ppr-smrs: ancient proteins with enigmatic functions.a small subset of the large pentatricopeptide repeat (ppr) protein family in higher plants contain a c-terminal small muts-related (smr) domain. although few in number, they figure prominently in the chloroplast biogenesis and retrograde signaling literature due to their striking mutant phenotypes. in this review, we summarize current knowledge of ppr-smr proteins focusing on arabidopsis and maize proteomic and mutant studies. we also examine their occurrence in other organisms and have determin ...201324004908
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