| the structural basis of actin filament branching by the arp2/3 complex. | the actin-related protein 2/3 (arp2/3) complex mediates the formation of branched actin filaments at the leading edge of motile cells and in the comet tails moving certain intracellular pathogens. crystal structures of the arp2/3 complex are available, but the architecture of the junction formed by the arp2/3 complex at the base of the branch was not known. in this study, we use electron tomography to reconstruct the branch junction with sufficient resolution to show how the arp2/3 complex inter ... | 2008 | 18316411 |
| effect of human tears on acanthamoeba-induced cytopathic effect. | to determine whether tears of healthy individuals provide protection against acanthamoeba-induced cytopathic effect (cpe) in vitro. | 2008 | 18332314 |
| in vitro evaluation of the amoebicidal activity of garlic (allium sativum) extract on acanthamoeba castellanii and its cytotoxic potential on corneal cells. | free-living protozoa of the genus acanthamoeba can cause one of the most severe, potentially sight-threatening infections of the eye, the so-called a. keratitis. a. keratitis is difficult to treat because, under adverse conditions, the amoeba encyst and medical therapy is often less effective against cysts than against trophozoites. the aim of this study was to investigate evaluate the in vitro effect of the nonpolar subfraction of the methanol extract of garlic (allium sativum) on the growth of ... | 2008 | 18370873 |
| computational screen for spliceosomal rna genes aids in defining the phylogenetic distribution of major and minor spliceosomal components. | the rna molecules of the spliceosome are critical for specificity and catalysis during splicing of eukaryotic pre-mrna. in order to examine the evolution and phylogenetic distribution of these rnas, we analyzed 149 eukaryotic genomes representing a broad range of phylogenetic groups. rnas were predicted using high-sensitivity local alignment methods and profile hmms in combination with covariance models. the results provide the most comprehensive view so far of the phylogenetic distribution of s ... | 2008 | 18390578 |
| redox state of quinone affects sensitivity of acanthamoeba castellanii mitochondrial uncoupling protein to purine nucleotides. | we studied ffa (free fatty acid)-induced uncoupling activity in acanthamoeba castellanii mitochondria in the non-phosphorylating state. either succinate or external nadh was used as a respiratory substrate to determine the proton conductance curves and the relationships between respiratory rate and the quinone reduction level. our determinations of the membranous quinone reduction level in non-phosphorylating mitochondria show that activation of ucp (uncoupling protein) activity leads to a pn (p ... | 2008 | 18402555 |
| significant role for ladc in initiation of legionella pneumophila infection. | previously, we identified ladc in a cohort of genes that were present in legionella pneumophila but absent in other legionella species. here we constructed a ladc mutant of l. pneumophila and assessed its ability to replicate in mammalian cell lines and acanthamoeba castellanii. the ladc mutant was recovered in significantly lower numbers than wild-type l. pneumophila at early time points, which was reversed upon transcomplementation with ladc but not ladc(n430a/r434a), encoding a putative catal ... | 2008 | 18426879 |
| [prolactin as a modulator of antiparasitic immunity]. | prolactin (prl) is a polypeptide hormone of the pituitary origin, that expresses over 300 separate biological activities, including its involvement in the regulation of immune functions. the hormone's immune capacities are related, among others, to comitogenic activity, prevention of immune cell apoptosis, stimulation of interleukins and antibodies production. prolactin acts as a potent positive modulator of immunity to some protozoan parasites. it is well established that the hormone stimulates ... | 2007 | 18441871 |
| pseudomonas aeruginosa utilises its type iii secretion system to kill the free-living amoeba acanthamoeba castellanii. | pseudomonas aeruginosa is a free-living and common environmental bacterium. it is an opportunistic and nosocomial pathogen causing serious human health problems. to overcome its predators, such as macrophages and environmental phagocytes, it utilises different survival strategies, such as the formation of microcolonies and the production of toxins mediated by a type iii secretion system (ttss). the aim of this study was to examine interaction of ttss effector proteins of p. aeruginosa pa103 with ... | 2008 | 18460161 |
| encystment of acanthamoeba during incubation in multipurpose contact lens disinfectant solutions and experimental formulations. | acanthamoeba keratitis (ak) is most commonly found in contact lens wearers with poor lens care hygiene. recent reports have indicated an increase in cases of ak in the united states associated with the use of complete moistureplus multipurpose solution. this association may not appear explainable by differences in acanthamoeba kill rates among multipurpose solutions. in this study the physiologic response of acanthamoeba trophozoites to incubation in various contact lens solutions was investigat ... | 2008 | 18463477 |
| predator or prey? chlamydophila abortus infections of a free-living amoebae, acanthamoeba castellani 9gu. | limited evidence exists to suggest that the ability to invade and escape protozoan host cell bactericidal activity extends to members of the chlamydiaceae, intracellular pathogens of humans and animals and evolutionary descendants of amoeba-resisting chlamydia-like organisms. pcr and microscopic analyses of chlamydophila abortus infections of acanthamoeba castellani revealed uptake of this chlamydial pathogen but, unlike the well-described inhabitant of a. castellani, parachlamydia acanthamoebae ... | 2008 | 18467146 |
| pseudomonas aeruginosa uses type iii secretion system to kill biofilm-associated amoebae. | bacteria and protozoa coexist in a wide range of biofilm communities of natural, technical and medical importance. generally, this interaction is characterized by the extensive grazing activity of protozoa on bacterial prey populations. we hypothesized that the close spatial coexistence in biofilms should allow opportunistic pathogenic bacteria to utilize their eukaryote-targeting arsenal to attack and exploit protozoan host cells. studying cocultures of the environmental pathogen pseudomonas ae ... | 2008 | 18480848 |
| acanthamoeba castellanii: identification and distribution of actin cytoskeleton. | the presence of the cytoskeleton of acanthamoeba castellanii was observed by means of cryo-electronmicroscopy and immunofluorescence techniques. this structure is formed largely by fibers and networks of actin located mainly in cytoplasmic locomotion structures as lamellipodia and as well as in various endocytic structures. in addition, the comparison between total actin content in whole extracts among different amoebae was made. the molecular weight of actin in a. castellanii was 44 kda, and 45 ... | 2008 | 18486940 |
| temperature-dependent parasitic relationship between legionella pneumophila and a free-living amoeba (acanthamoeba castellanii). | we analyzed the effects of temperature on the interaction of legionella pneumophila with acanthamoeba castellanii. at <20 degrees c, overexpression of type 1 metacaspase, a stimulator of a. castellanii encystation, was associated with a reduced number of bacteria within amoeba. at low temperatures, a. castellanii seems to eliminate l. pneumophila by encystation and digestion. | 2008 | 18502936 |
| basic energetic parameters of acanthamoeba castellanii mitochondria and their resistance to oxidative stress. | the purpose of this study was establishing the basic energetic parameters of amoeba acanthamoeba castellanii mitochondria respiring with malate and their response to oxidative stress caused by hydrogen peroxide in the presence of fe(2+) ions. it appeared that, contrary to a previous report (trocha lk, stobienia o (2007) acta biochim polon 54: 797), h(2)o(2)-treated mitochondria of a. castellanii did not display any substantial impairment. no marked changes in cytochrome pathway activity were fou ... | 2008 | 18542832 |
| the role of proteases in the differentiation of acanthamoeba castellanii. | proteases are significant determinants of protozoan pathogenicity and cytolysis of host cells. however, there is now growing evidence of their involvement in cellular differentiation. acanthamoeba castellanii of the t4 genotype elaborates a number of proteases, which are inhibited by the serine protease inhibitor phenylmethylsulphonyl fluoride. using this and other selective protease inhibitors, in tandem with sirna primers, specific to the catalytic site of acanthamoeba serine proteases, we dem ... | 2008 | 18616591 |
| importance of type ii secretion for survival of legionella pneumophila in tap water and in amoebae at low temperatures. | legionella pneumophila type ii secretion mutants showed reduced survival in both tap water at 4 to 17 degrees c and aquatic amoebae at 22 to 25 degrees c. wild-type supernatants stimulated the growth of these mutants, indicating that secreted factors promote low-temperature survival. there was a correlation between low-temperature survival and secretion function when 12 additional legionella species were examined. | 2008 | 18621869 |
| modulation of corneal and stromal matrix metalloproteinase by the mannose-induced acanthamoeba cytolytic protein. | the involvement of the mannose-induced acanthamoeba cytopathic protein (mip-133) in tissue injury and activation of metalloproteinase of corneal and stromal cells was examined in vitro. activation of mmp-1, mmp-2, mmp-3, and mmp-9 induced by mip-133 on human corneal epithelial and stromal cell cultures was examined by reverse transcriptase polymerase chain reaction (rt-pcr) and elisa. mmp-1, mmp-2, mmp-3, and mmp-9 mrna were expressed in both cultured human corneal epithelial and stromal cells. ... | 2008 | 18627771 |
| biodiversity of amoebae and amoebae-resisting bacteria in a drinking water treatment plant. | the complex ecology of free-living amoebae (fla) and their role in spreading pathogenic microorganisms through water systems have recently raised considerable interest. in this study, we investigated the presence of fla and amoebae-resisting bacteria (arb) at various stages of a drinking water plant fed with river water. we isolated various amoebal species from the river and from several points within the plant, mostly at early steps of water treatment. echinamoeba- and hartmannella-related amoe ... | 2008 | 18637950 |
| the virophage as a unique parasite of the giant mimivirus. | viruses are obligate parasites of eukarya, archaea and bacteria. acanthamoeba polyphaga mimivirus (apmv) is the largest known virus; it grows only in amoeba and is visible under the optical microscope. mimivirus possesses a 1,185-kilobase double-stranded linear chromosome whose coding capacity is greater than that of numerous bacteria and archaea1, 2, 3. here we describe an icosahedral small virus, sputnik, 50 nm in size, found associated with a new strain of apmv. sputnik cannot multiply in aca ... | 2008 | 18690211 |
| acanthamoeba castellanii an environmental host for shigella dysenteriae and shigella sonnei. | the interaction between shigella dysenteriae or shigella sonnei and acanthamoeba castellanii was studied by viable counts, gentamicin assay and electron microscopy. the result showed that shigella dysenteriae or shigella sonnei grew and survived in the presence of amoebae for more than 3 weeks. gentamicin assay showed that the shigella were viable inside the acanthamoeba castellanii which was confirmed by electron microscopy that showed the shigella localized in the cytoplasm of the acanthamoeba ... | 2009 | 18712360 |
| phosphorylation of the arp2/3 complex is necessary to nucleate actin filaments. | the actin-related protein 2/3 (arp2/3) complex is the primary nucleator of new actin filaments in most crawling cells. nucleation-promoting factors (npfs) of the wiskott-aldrich syndrome protein (wasp)/scar family are the currently recognized activators of the arp2/3 complex. we now report that the arp2/3 complex must be phosphorylated on either threonine or tyrosine residues to be activated by npfs. phosphorylation of the arp2/3 complex is not necessary to bind npfs or the sides of actin filame ... | 2008 | 18725535 |
| in vitro evaluation of the amebicidal activity of pterocaulon polystachyum (asteraceae) against trophozoites of acanthamoeba castellanii. | the crude extract and hexane, dichloromethane, and methanol fractions obtained from the aerial parts of pterocaulon polystachyum (asteraceae) were assayed against acanthamoeba castellanii, a free-living ameba that causes acute amebic keratitis. because of its capacity to form cysts, some strains of this protozoan are excellent opportunists and therapy resistant, necessitating a search for new drugs in order to develop more dynamic therapies that make it easier for patients to maintain long-term ... | 2008 | 18795331 |
| synergistic contribution of the legionella pneumophila lqs genes to pathogen-host interactions. | the causative agent of legionnaires' disease, legionella pneumophila, is a natural parasite of environmental protozoa and employs a biphasic life style to switch between a replicative and a transmissive (virulent) phase. l. pneumophila harbors the lqs (legionella quorum sensing) cluster, which includes genes encoding the autoinducer synthase lqsa, the sensor kinase lqss, the response regulator lqsr, and a homologue of hded, which is involved in acid resistance in escherichia coli. lqsr promotes ... | 2008 | 18805977 |
| growth, encystment and survival of acanthamoeba castellanii grazing on different bacteria. | free-living amoebae of the genus acanthamoeba are widely distributed in soil and water collections, where trophozoites (vegetative, multiplicative stages) feed mainly by phagocytosis and thus control bacterial populations in the environment. here, we examined the growth, encystment and survival of acanthamoeba castellanii receiving different bacteria (escherichia coli, pseudomonas aeruginosa, enterobacter cloacae, bacillus subtilis, bacillus megaterium, micrococcus luteus, and staphylococcus aur ... | 2008 | 18811648 |
| cytoskeletal regulation: coordinating actin and microtubule dynamics in membrane trafficking. | the arp2/3 complex is essential for actin nucleation and filament elongation in a variety of intracellular processes. this functional versatility is exerted through the regulation of its activity by nucleation-promoting factors (npfs). the discovery of a new npf, whamm, reveals unexpected connections between the actin and microtubule cytoskeletons and membrane dynamics during er-to-golgi transport. | 2008 | 18812086 |
| oxygen and the spatial structure of microbial communities. | oxygen has two faces. on one side it is the terminal electron acceptor of aerobic respiration - the most efficient engine of energy metabolism. on the other hand, oxygen is toxic because the reduction of molecular o2 creates reactive oxygen species such as the superoxide anion, peroxide, and the hydroxyl radical. probably most prokaryotes, and virtually all eukaryotes, depend on oxygen respiration, and we show that the ambiguous relation to oxygen is both an evolutionary force and a dominating f ... | 2008 | 18823390 |
| long-term survival of legionella pneumophila in the viable but nonculturable state after monochloramine treatment. | legionella pneumophila, a facultative intracellular human pathogen, can persist for long periods in natural and artificial aquatic environments. eradication of this bacterium from plumbing systems is often difficult. we tested l. pneumophila survival after monochloramine treatment. survival was monitored using the baclight bacterial viability kit (molecular probes), chemchrome v6 kit (chemunex), quantitative polymerase chain reaction and culturability on buffered charcoal-yeast extract agar. in ... | 2008 | 18839249 |
| acanthamoeba castellanii promotes the survival of vibrio parahaemolyticus. | vibrio parahaemolyticus is a food-borne pathogen that naturally inhabits both marine and estuarine environments. free-living protozoa exist in similar aquatic environments and function to control bacterial numbers by grazing on free-living bacteria. protozoa also play an important role in the survival and spread of some pathogenic species of bacteria. we investigated the interaction between the protozoan acanthamoeba castellanii and the bacterium vibrio parahaemolyticus. we found that acanthamoe ... | 2008 | 18849458 |
| induced encystment improves resistance to preservation and storage of acanthamoeba castellanii. | several conditions that allow the preservation, storage and rapid, efficient recovery of viable acanthamoeba castellanii organisms were investigated. the viability of trophozoites (as determined by time to confluence) significantly declined over a period of 12 months when stored at -70 degrees c using dimethyl sulfoxide (dmso; 5 or 10%) as cryopreservant. as a. castellanii are naturally capable of encystment, studies were undertaken to determine whether induced encystment might improve the viabi ... | 2008 | 18937883 |
| toxoplasma gondii: uptake and survival of oocysts in free-living amoebae. | waterborne transmission of the oocyst stage of toxoplasma gondii can cause outbreaks of clinical toxoplasmosis in humans and infection of marine mammals. in water-related environments and soil, free-living amoebae are considered potential carriers of various pathogens, but knowledge on interactions with parasitic protozoa remains elusive. in the present study, we assessed whether the free-living acanthamoeba castellanii, due to its phagocytic activity, can interact with t. gondii oocysts. we rep ... | 2009 | 18992742 |
| in vitro activity of acanthamoeba castellanii on human platelets and erythrocytes. | the effect of acanthamoeba on human platelets and erythrocytes has not been fully elucidated. this paper reports that cell-free supernatants prepared from a. castellanii can activate human platelets, causing both a significant increase in the cytosolic free-calcium concentration and platelet aggregation. in addition, we demonstrated that platelet activation depends on the activity of adp constitutively secreted into the medium by trophozoites. this study also showed that a. castellanii can affec ... | 2009 | 19015256 |
| free-living freshwater amoebae differ in their susceptibility to the pathogenic bacterium legionella pneumophila. | legionella pneumophila is known as a facultative intracellular parasite of free-living soil and freshwater amoebae, of which several species have been shown to support the growth of the pathogenic bacteria. we report for the first time the behaviour of two strains (c2c and z503) of the amoeba willaertia magna towards different strains of l. pneumophila serogroup 1 and compared it with acanthamoeba castellanii and hartmannella vermiformis, known to be l. pneumophila permissive. in contrast to the ... | 2009 | 19016880 |
| assessment of balamuthia mandrillaris-specific serum antibody concentrations by flow cytometry. | a flow cytometry (fluorescence-activated cell sorter)-based assay was adapted to detect and quantify antibodies to balamuthia mandrillaris, a causative agent of fatal amoebic encephalitis (bae), and to acanthamoeba species. with sera from bae patients for positive and a group of inconspicuous volunteers for negative reference, most of the 237 sera from random blood donors, patients with atypical encephalitis, atypical pneumonitis, visceral amoebiasis and toxoplasmosis and from subjects working w ... | 2009 | 19039606 |
| heterogeneity in chlorine susceptibility for legionella pneumophila released from acanthamoeba and hartmannella. | to assess chlorine susceptibility of legionella pneumophila grown from two amoebic hosts, acanthamoeba castellanii and hartmannella vermiformis. | 2009 | 19040705 |
| acanthamoeba castellanii: high antibody prevalence in racially and ethnically diverse populations. | acanthamoeba is an opportunistic protozoan pathogen that can produce keratitis and rare but fatal encephalitis. in the present study, we examined secretory iga antibody to acanthamoeba castellanii of the t4 genotype in mucosal secretions from 114 individuals of 37 countries, inhabitants and/or visitors, aged 16-65 years in london, uk. acanthamoeba antibody prevalence rate was more than 85%, without any significant differences between males (86.2%) and females (89.2%). some epidemiological factor ... | 2009 | 19071116 |
| vibrio cholerae o139 requires neither capsule nor lps o side chain to grow inside acanthamoeba castellanii. | vibrio cholerae, the causative agent of cholera, has the ability to grow and survive in the aquatic free-living amoeba acanthamoeba castellanii. the aim of the present study was to examine the ability of the clinical isolate v. cholerae o139 mo10 to grow in a. castellanii and to determine the effect of the bacterial capsule and lps o side chain on intracellular growth. results from co-cultivation, viable counts, a gentamicin assay, electron microscopy and statistical analysis showed that the ass ... | 2009 | 19074664 |
| relationships between free living amoebae and exophiala dermatitidis: a preliminary study. | free living amoebae can play a role as reservoirs for pathogens isolated from hospital water. we have investigated the potential interactions between two protozoa (acanthamoeba castellanii and hartmanella vermiformis) that may be recovered from hospital water tips and exophiala dermatitidis, a black yeast often recovered from water sources. we showed that the presence of trophozoites or supernatants of culture of h. vermiformis increased fungal growth, whereas the same phenomenon was observed on ... | 2009 | 19085458 |
| a simple method for long-term storage of acanthamoeba species. | we present a novel and simple technique for storing live acanthamoeba for long periods of time. the amoebae are maintained at refrigerator temperatures in a peptone-yeast extract-glucose (pyg) medium normally used for cultivation. using this method, we obtained survival rates of at least 4 years for acanthamoeba polyphaga and 3 years for acanthamoeba castellanii and acanthamoeba rhysodes. advantages of this storage method are: (1) it is quick and simple, (2) inexpensive, (3) does not require enc ... | 2009 | 19089450 |
| a comparison of regimen methods for the removal and inactivation of bacteria, fungi and acanthamoeba from two types of silicone hydrogel lenses. | to compare the antimicrobial efficacy of commercial contact lens solutions when used according to the manufacturers' recommended regimens with two types of silicone hydrogel lenses. | 2009 | 19201251 |
| reciprocal expression of integration host factor and hu in the developmental cycle and infectivity of legionella pneumophila. | legionella pneumophila is an intracellular parasite of protozoa that differentiates late in infection into metabolically dormant cysts that are highly infectious. regulation of this process is poorly understood. here we report that the small dna binding regulatory proteins integration host factor (ihf) and hu are reciprocally expressed over the developmental cycle, with hu expressed during exponential phase and ihf expressed postexponentially. to assess the role of these regulatory proteins in d ... | 2009 | 19201975 |
| effect of free versus liposomal-complexed pentamidine isethionate on biological characteristics of acanthamoeba castellanii in vitro. | acanthamoeba is an opportunistic protozoan pathogen that can cause blinding keratitis and a rare but fatal encephalitis involving the central nervous system with a very poor prognosis. this is due to limited availability of effective anti-acanthamoebic drugs. here, we tested whether the use of liposomes can improve the potency of pentamidine isethionate, an anti-amoebic compound. the liposomes consisted of l-alpha-phosphatidylcholine and cholesterol or ergosterol in a molar ratio of 1 : 5. penta ... | 2009 | 19208882 |
| soil amoebae rapidly change bacterial community composition in the rhizosphere of arabidopsis thaliana. | we constructed an experimental model system to study the effects of grazing by a common soil amoeba, acanthamoeba castellanii, on the composition of bacterial communities in the rhizosphere of arabidopsis thaliana. amoebae showed distinct grazing preferences for specific bacterial taxa, which were rapidly replaced by grazing tolerant taxa in a highly reproducible way. the relative proportion of active bacteria increased although bacterial abundance was strongly decreased by amoebae. specific bac ... | 2009 | 19242534 |
| the role of free-living pathogenic amoeba in the transmission of leprosy: a proof of principle. | leprosy transmission remains poorly understood, though, prolonged skin contact and/or infection via nasal mucosa, are considered likely. problematic in any transmission hypothesis is the fastidious nature of mycobacterium leprae outside its host cell and the requirement for temporary survival in the environment, soil or water. experiments were carried out to test the hypothesis that free living pathogenic amoeba might serve as host cells for m. leprae, protecting them from adverse environmental ... | 2008 | 19274986 |
| predators promote defence of rhizosphere bacterial populations by selective feeding on non-toxic cheaters. | soil pseudomonads increase their competitiveness by producing toxic secondary metabolites, which inhibit competitors and repel predators. toxin production is regulated by cell-cell signalling and efficiently protects the bacterial population. however, cell communication is unstable, and natural populations often contain signal blind mutants displaying an altered phenotype defective in exoproduct synthesis. such mutants are weak competitors, and we hypothesized that their fitness depends on natur ... | 2009 | 19322247 |
| antibiotic susceptibility of waddlia chondrophila in acanthamoeba castellanii amoebae. | waddlia chondrophila is an emerging cause of miscarriage in bovines and humans. given the strict intracellular growth of this chlamydia-like organism, its antibiotic susceptibility was tested by amoebal coculture, cell culture, and real-time pcr. w. chondrophila was susceptible to doxycycline and azithromycin but resistant to beta-lactams and fluoroquinolones. | 2009 | 19332673 |
| development of a liquid chromatography-based screening methodology for proteolytic enzyme activity. | a new methodology for the detection and isolation of serine proteases in complex mixtures has been developed. it combines the characterization of crude samples by electrospray tandem mass spectrometry (esi-ms/ms) in a multi-substrate assay and the differentiated sensitive detection of the responsible enzymes by means of liquid chromatography hyphenated online to biochemical detection (bcd). first, active samples are identified in the multi-substrate assay monitoring the conversion of eight subst ... | 2009 | 19349051 |
| regulation of acanthamoeba castellanii alternative oxidase activity by mutual exclusion of purine nucleotides; atp's inhibitory effect. | the effects of different adenine and guanine nucleotides on the cyanide-resistant respiration (i.e. alternative oxidase (acaox) activity) of mitochondria from the amoeba a. castellanii mitochondria were studied. we found that guanine nucleotides activate acaox to a greater degree than adenine nucleotides, and that nucleoside monophosphates were more efficient activators than nucleoside di- or triphosphates. the extent of the nucleotides' influence on acaox was dependent on the medium's ph and wa ... | 2009 | 19366609 |
| carbohydrate analysis of acanthamoeba castellanii. | we analyzed biochemically acanthamoeba castellanii trophozoites, intact cysts and cyst walls belonging to the t4 genotype using gas chromatography combined with mass spectrometry. cyst walls were prepared by removing intracellular material from cysts by pre-treating them with sodium dodecyl sulphate (sds) containing dithiothreitol, and then subjecting these to a series of sequential enzymatic digestions using amyloglucosidase, papain, dnase, rnase and proteinase k. the resulting "cyst wall" mate ... | 2009 | 19389397 |
| two small ncrnas jointly govern virulence and transmission in legionella pneumophila. | to transit from intra- to extracellular environments, legionella pneumophila differentiates from a replicative/non-virulent to a transmissive/virulent form using the two-component system leta/lets and the global repressor protein csra. while investigating how both regulators act co-ordinately we characterized two ncrnas, rsmy and rsmz, that link the leta/lets and csra regulatory networks. we demonstrate that leta directly regulates their expression and show that rsmy and rsmz are functional in e ... | 2009 | 19400772 |
| resistance of acanthamoeba cysts to disinfection in multiple contact lens solutions. | acanthamoebae are free-living amoebae found in the environment, including soil, freshwater, brackish water, seawater, hot tubs, and jacuzzis. acanthamoeba species can cause keratitis, a painful vision-threatening infection of the cornea, and fatal granulomatous encephalitis in humans. more than 20 species of acanthamoeba belonging to morphological groups i, ii, and iii distributed in 15 genotypes have been described. among these, acanthamoeba castellanii, a. polyphaga, and a. hatchetti are frequ ... | 2009 | 19403771 |
| bdha-patd operon as a virulence determinant, revealed by a novel large-scale approach for identification of legionella pneumophila mutants defective for amoeba infection. | legionella pneumophila, the causative agent of legionnaires' disease, is an intracellular parasite of eukaryotic cells. in the environment, it colonizes amoebae. after being inhaled into the human lung, the bacteria infect and damage alveolar cells in a way that is mechanistically similar to the amoeba infection. several l. pneumophila traits, among those the dot/icm type ivb protein secretion machinery, are essential for exploiting host cells. in our search for novel legionella virulence factor ... | 2009 | 19411431 |
| in vitro amoebicidal activity of salvia staminea and salvia caespitosa on acanthamoeba castellanii and their cytotoxic potentials on corneal cells. | amoebic keratitis is difficult to treat with total efficacy in some patients because of cysts, which are less susceptible than trophozoites to the usual treatments. we investigated the in vitro effectiveness of methanolic extract of salvia staminea and salvia caespitosa against acanthamoeba castellanii, as well as their cytotoxicity on corneal cells in vitro. | 2009 | 19450152 |
| survey of pathogenic free-living amoebae and legionella spp. in mud spring recreation area. | acanthamoeba, hartmannella, and naegleria are free-living amoebae, ubiquitous in aquatic environments. several species within these genera are recognized as potential human pathogens. these free-living amoebae may facilitate the proliferation of their parasitical bacteria, such as legionella. in this study, we identified acanthamoeba, hartmannella, naegleria, and legionella using various analytical procedures and investigated their occurrence at a mud spring recreation area in taiwan. we investi ... | 2009 | 19457534 |
| acanthamoeba alternative oxidase genes: identification, characterisation and potential as antimicrobial targets. | alternative oxidase (aox) is a mitochondrial protein that acts as an alternative terminal oxidase to the conventional cytochrome oxidases. it is present in certain prokaryotes, plants, fungi and some protozoa but absent in mammals. aox activity has previously been described in acanthamoeba, although no genetic evidence has been reported. herein, two aox (acaox) genes designated isoforms a and b, were obtained from acanthamoeba castellanii by a combination of degenerate pcr from cdna and a series ... | 2009 | 19464295 |
| ante mortem diagnosis of amoebic encephalitis in a haematopoietic stem cell transplanted patient. | acanthamoeba species are widely distributed free-living amoebae showing an increased role as human pathogens causing encephalitis, keratitis, pneumonitis and dermatitis. a haematopoietic stem cell transplanted (hsct) patient developed purulent meningitis while awaiting regrafting. the meningitis was thought to be an endogenous infection arising from the mucous membranes primarily involving the cervicofacial regions, probably due to haematogenous spread facilitated by surgery. we diagnosed a fata ... | 2009 | 19479635 |
| differential effects of alpha-helical and beta-hairpin antimicrobial peptides against acanthamoeba castellanii. | in this work we evaluated the ability of different types of antimicrobial peptides to promote permeabilization and growth inhibition of acanthamoeba castellanii trophozoites, which cause eye keratitis. we used cationic alpha-helical peptides p5 and p6, corresponding to the n-terminus of the pore-forming protein from triatoma infestans, a blood-sucking insect, and a beta-hairpin amphipathic molecule (gomesin), of the spider acanthoscurria gomesiana haemocytes. a. castellanii permeabilization was ... | 2009 | 19490729 |
| transcriptional down-regulation and rrna cleavage in dictyostelium discoideum mitochondria during legionella pneumophila infection. | bacterial pathogens employ a variety of survival strategies when they invade eukaryotic cells. the amoeba dictyostelium discoideum is used as a model host to study the pathogenic mechanisms that legionella pneumophila, the causative agent of legionnaire's disease, uses to kill eukaryotic cells. here we show that the infection of d. discoideum by l. pneumophila results in a decrease in mitochondrial messenger rnas, beginning more than 8 hours prior to detectable host cell death. these changes can ... | 2009 | 19492077 |
| tissue microarray and immunohistochemistry as tools for evaluation of antibodies against chlamydia-like bacteria. | tissue microarray technology was used to establish immunohistochemistry protocols and to determine the specificity of new antisera against various chlamydia-like bacteria for future use on formalin-fixed and paraffin-embedded tissues. the antisera exhibited strong reactivity against autologous antigen and closely related heterologous antigen, but no cross-reactivity with distantly related species. | 2009 | 19498205 |
| acanthamoeba castellanii: proteins involved in actin dynamics, glycolysis, and proteolysis are regulated during encystation. | acanthamoeba castellanii is a pathogenic free-living amoeba. cyst forms are particularly important in their pathogenicity, as they are more resistant to treatments and might protect pathogenic intracellular bacteria. however, encystation is poorly understood at the molecular level and global changes at the protein level have not been completely described. in this study, we performed two-dimensional gel electrophoresis to compare protein expression in trophozoite and cyst forms. four proteins, sp ... | 2009 | 19523468 |
| length and sequence heterogeneity in the mitochondrial internal transcribed spacer of acanthamoeba spp. | the internal transcribed spacer (its) between the mitochondrial large (23s rrna; rnl) and small (16s rrna; rns) subunit ribosomal rna genes of acanthamoeba castellanii strain neff was sequenced previously and was uniquely interesting because it contained trna genes with acceptor stem mismatches that underwent rna editing repair. our interest in this its region was to determine its phylogenetic potential in differentiating between closely related isolates. we analyzed the mitochondrial its region ... | 2009 | 19527353 |
| autophagy protein 8 mediating autophagosome in encysting acanthamoeba. | autophagy is an evolutionally conserved protein degradation pathway in eukaryotes. it plays essential roles during starvation, cellular differentiation, cell death, and aging by eliminating unwanted or unnecessary organelles and recycling the components for reuse. atg8, a member of a novel ubiquitin-like protein family, is an essential component of the autophagic machinery. the present study identified and characterized autophagy protein 8 in acanthamoeba castellanii an amphizoic amoeba causing ... | 2009 | 19560492 |
| first case of granulomatous amebic encephalitis caused by acanthamoeba castellanii in taiwan. | we report the first case of granulomatous amebic encephalitis caused by acanthamoeba in a previously healthy farmer in taiwan who fell into a ditch. the dna amplicons of amebas identified by polymerase chain reaction in the cerebrospinal fluid specimen and the ditch water specimens were identical and shared strong homology with a. castellanii . he survived after treatment with amphotericin b, rifampin, and corticosteroids. | 2009 | 19635883 |
| viability of listeria monocytogenes in co-culture with acanthamoeba spp. | listeria monocytogenes is a human pathogen, ubiquitous in the environment, and can grow and survive under a wide range of environmental conditions. it contaminates foods via raw materials or food-processing environments. however, the current knowledge of its ecology and, in particular, the mode of environmental survival and transmission of this intracellular pathogen remains limited. research has shown that several intracellular pathogens are able to survive or replicate within free-living amoeb ... | 2009 | 19645820 |
| effects of multipurpose contact lens care solutions on the adhesiveness of acanthamoeba to corneal epithelial cells. | to study the adhesion of acanthamoeba castellanii treated with multipurpose contact lens care solutions (mpss) to human corneal epithelial cells. | 2009 | 19672197 |
| acanthamoeba castellanii : growth on human cell layers reactivates attenuated properties after prolonged axenic culture. | the free-living, but potentially pathogenic, bacteriovorous amoebae of the genus acanthamoeba can be easily grown axenically in a laboratory culture. this, however, often leads to considerable losses in virulence, and encystment capacity, and to changes in drug susceptibility. we evaluated potential options for a reactivation of a number of physiological properties, attenuated by prolonged axenic laboratory culture, including encystment potential, protease activity, heat resistance, growth rates ... | 2009 | 19732153 |
| an ancient fission of mitochondrial cox1. | many genes inherited from the alpha-proteobacterial ancestor of mitochondria have undergone evolutionary transfer to the nuclear genome in eukaryotes. in some rare cases, genes have been functionally transferred in pieces, resulting in split proteins that presumably interact in trans within mitochondria, fulfilling the same role as the ancestral, intact protein. we describe a nucleus-encoded mitochondrial protein (here named cox1-c) in the amoeboid protist acanthamoeba castellanii that is homolo ... | 2010 | 19767348 |
| acanthamoeba polyphaga is a possible host for vibrio cholerae in aquatic environments. | acanthamoeba is a genus of free-living amoebae found to be able to host many bacterial species living in the environment. acanthamoebae and vibrio cholerae are found in the aquatic environments of cholera endemic areas. previously it has been shown that v. cholerae o1 and o139 can survive and grow in acanthamoeba castellanii. the aim of this study was to examine the ability of acanthamoeba polyphaga to host v. cholerae o1 and o139. the interaction between a. polyphaga and v. cholerae strains was ... | 2010 | 19815016 |
| legionella pneumophila secretes an endoglucanase that belongs to the family-5 of glycosyl hydrolases and is dependent upon type ii secretion. | examination of cell-free culture supernatants revealed that legionella pneumophila strains secrete an endoglucanase activity. legionella pneumophila lspf mutants were deficient for this activity, indicating that the endoglucanase is secreted by the bacterium's type ii protein secretion (t2s) system. inactivation of cela, encoding a member of the family-5 of glycosyl hydrolases, abolished the endoglucanase activity in l. pneumophila culture supernatants. the cloned cela gene conferred activity up ... | 2009 | 19817866 |
| francisella tularensis type a strains cause the rapid encystment of acanthamoeba castellanii and survive in amoebal cysts for three weeks postinfection. | francisella tularensis, the causative agent of the zoonotic disease tularemia, has recently gained increased attention due to the emergence of tularemia in geographical areas where the disease has been previously unknown and to the organism's potential as a bioterrorism agent. although f. tularensis has an extremely broad host range, the bacterial reservoir in nature has not been conclusively identified. in this study, the ability of virulent f. tularensis strains to survive and replicate in the ... | 2009 | 19820161 |
| [regulation of cortical cytoskeleton dynamics during migration of free-living amoebae]. | amoeba proteus and smaller by an order of magnitude (and evolutionary younger) acanthamoeba castellanii have been for many years model cells for studies of amoeboidal (crawling) type of movement, characteristic also for some of metazoan cells such as fibroblasts, granulocytes and macrophages. amoeboidal migration is indispensable of organization and dynamics of actin-based cytoskeleton. while there is a number of data on molecular mechanisms of motility of a. castellanii, there is very little kn ... | 2009 | 19824468 |
| the effect of surface treatment of silicone hydrogel contact lenses on the attachment of acanthamoeba castellanii trophozoites. | to determine if plasma surface treatment of focus night & day silicone hydrogel contact lenses affects the attachment of acanthamoeba. | 2009 | 19826253 |
| expression plasmids and production of egfp in stably transfected acanthamoeba. | new plasmids containing the tata-binding protein (tbp), tbp promoter binding factor (tpbf) or glyceraldehyde phosphate dehydrogenase (gapdh) gene promoters from acanthamoeba castellanii are described. the promoters for acanthamoeba tpbf and gapdh genes were used to drive constitutive expression of enhanced green fluorescent protein (egfp) in stably transfected acanthamoeba. based initially on fluorescence microscopy and sds-page analysis of egfp, both promoters produce robust expression of egfp, ... | 2010 | 19836453 |
| evaluation of power ultrasound for disinfection of both legionella pneumophila and its environmental host acanthamoeba castellanii. | the objectives of this study were to (1) examine the effect of power ultrasound on the viability of both legionella pneumophila and acanthamoeba castellanii trophozoites and cysts, (2) investigate if intracellular legionella replication in trophozoites positively affects bacterial resistance to ultrasound and (3) study if legionella renders viable but non-culturable (vbnc) due to ultrasound treatments. using laboratory scale experiments, microorganisms were exposed for various time periods to po ... | 2010 | 19854466 |
| acanthamoeba spp.: in vitro effects of clinical isolates on murine macrophages, osteosarcoma and hela cells. | three different cell lines (murine macrophages, hela and osteosarcoma cells) were assayed in order to check for the manifestation of the cytopathic effects of three strains of acanthamoeba recently isolated in our laboratory from contact lens cases: clc-16, clc-41.r and clc-51-l. adhesion and cytotoxicity assays were carried out with these strains and the type strain acanthamoeba castellanii neff as a control. briefly, the ability of these amoebae to bind to the three cell lines was calculated a ... | 2010 | 19857490 |
| relationships between nucleic acid synthetic patterns and encystment in aging unagitated cultures of acanthamoeba castellanii. | changes in the levels of dna and rna syntheses have been studied in unagitated cultures of acanthamoeba castellanii during the phases of logarithmic multiplication (lm) and population growth deceleration (pgd). pulse-labeling experiments show that the rate of dna synthesis decreases at the same time that dna per cell is known to drop by 50%. the drop in dna content has been explained by demonstrating with hydroxyurea that the majority of lm amebas can replicate once when dna synthesis is inhibit ... | 1971 | 19866775 |
| morphological changes and the requirements for macromolecule synthesis during excystment of acanthamoeba castellanii. | light and phase-contrast microscopic observations of excystment in acanthamoeba castellanii have been used to classify cells in excysting populations as free trophozoites, or mature, activated, or preemergent cysts. these categories have been used to describe the kinetics of excystment. a ph of 7 and a temperature of 30 degrees c have been found to be optimal for the activation of mature cysts. both activation and emergence are inhibited by cycloheximide and actinomycin d, but neither process is ... | 1971 | 19866776 |
| the tolc protein of legionella pneumophila plays a major role in multi-drug resistance and the early steps of host invasion. | pneumonia associated with iegionnaires's disease is initiated in humans after inhalation of contaminated aerosols. in the environment, legionella pneumophila is thought to survive and multiply as an intracellular parasite within free-living amoeba. in the genome of l. pneumophila lens, we identified a unique gene, tolc, encoding a protein that is highly homologous to the outer membrane protein tolc of escherichia coli. deletion of tolc by allelic exchange in l. pneumophila caused increased sensi ... | 2009 | 19888467 |
| the metal efflux island of legionella pneumophila is not required for survival in macrophages and amoebas. | legionella pneumophila is an intracellular pathogen causing pneumonia-like disease in humans. a 43-kb putative heavy metal efflux gene island was found on the l. pneumophila genome. large legionella deletion strains of the metal efflux genes were tested in human thp-1-derived macrophages and amoebal acanthamoeba castellanii cells and were able to survive and replicate similar to the wild type, suggesting that they do not play a significant role within the intracellular environment. examination o ... | 2009 | 19895645 |
| balamuthia and acanthamoeba-binding antibodies in west african human sera. | little is known about the prevalence of balamuthia mandrillaris amoebae and balamuthia amoebic encephalitis in africa. as an approach, relative concentrations of amoebae-binding serum antibodies (ab) were assessed by flow cytometry using formaldehyde-fixed b. mandrillaris, acanthamoeba lenticulata 72-2 and acanthamoeba castellanii 1bu amoebae for specific ab capture (b.m.-ab, a.l.-ab, a.c.-ab). one hundred and ninety-two sera from west african (côte d'ivoire) donors aged 11-95years (mean 38 a; 5 ... | 2010 | 19896940 |
| an epitope from acanthamoeba castellanii that cross-react with proteolipid protein 139-151-reactive t cells induces autoimmune encephalomyelitis in sjl mice. | we report here that an epitope (aa, 83-95) derived from acanthamoeba castellanii (aca) induces clinical signs of experimental autoimmune encephalomyelitis (eae) in sjl/j mice reminiscent of the disease induced with myelin proteolipid protein (plp) 139-151. by using ia(s)/tetramers, we demonstrate that both aca 83-95 and plp 139-151 generate antigen-specific cross-reactive cd4 t cells and the t cells secrete identical patterns of cytokines and induce eae with a similar severity. these results may ... | 2010 | 20005578 |
| disinfection efficacy and encystment rate of soft contact lens multipurpose solutions against acanthamoeba. | to assess the ability of commercial and experimental soft contact lens multipurpose solutions (mps) to promote acanthamoeba trophozoite encystment and their biocidal efficacy against acanthamoeba trophozoites and cysts. the effects on encystment and disinfection efficacy by the incorporation of propylene glycol (pg) in the formulation of mps were also investigated. | 2010 | 20009947 |
| uncoupling proteins in amoeboid eukaryotes, acanthamoeba castellanii, and dictyostelium discoideum. | uncoupling proteins, members of the mitochondrial carrier family, are present in the mitochondrial inner membrane, and they mediate free-fatty-acid-activated, purine nucleotide-inhibited proton reuptake. since 1999, it has been shown that uncoupling proteins are present in some eukaryotic microorganisms, including the amoeboid protozoon acanthamoeba castellanii and the amoeboid slime mold dictyostelium discoideum. in the mitochondria of these organisms, uncoupling protein activity is revealed by ... | 2004 | 20021114 |
| mitochondrial uncoupling proteins in unicellular eukaryotes. | uncoupling proteins (ucps) are members of the mitochondrial anion carrier protein family that are present in the mitochondrial inner membrane and mediate free fatty acid (ffa)-activated, purine nucleotide (pn)-inhibited proton conductance. since 1999, the presence of ucps has been demonstrated in some non-photosynthesising unicellular eukaryotes, including amoeboid and parasite protists, as well as in non-fermentative yeast and filamentous fungi. in the mitochondria of these organisms, ucp activ ... | 2010 | 20026010 |
| acanthamoeba castellanii: cellular changes induced by chlorination. | chlorination is a well-known disinfection method, used in water treatment to inactivate various microorganisms, it induces numerous cellular changes. even though acanthamoebae are frequently found in water, the cellular changes induced in acanthamoebae have not been described in the literature. acanthamoebae are pathogenic amoebae and may provide a reservoir for pathogenic bacteria such as legionellapneumophila; it is consequently important to understand the response of this amoeba to chlorinati ... | 2010 | 20034490 |
| acanthamoeba castellanii neff: in vitro activity against the trophozoite stage of a natural sesquiterpene and a synthetic cobalt(ii)-lapachol complex. | in this study, the in vitro activities of a natural sesquiterpene, alpha-cyperotundone, isolated from the root bark of maytenus retusa and a cobalt(ii)-complex of a natural occurring prenyl hydroxynaphthoquinone (lapachol) were evaluated against the trophozoite stage of acanthamoeba castellanii neff using a previously developed colorimetric 96-well microtiter plate assay, based on the oxido-reduction of alamar blue(r). the obtained activities showed that these two compounds were able to inhibit ... | 2010 | 20045692 |
| amoebae and algae can prolong the survival of campylobacter species in co-culture. | several species of free-living amoebae can cause disease in humans. however, in addition to the direct pathogenicity of e.g. acanthamoebae and naegleria species, they are recognized as environmental hosts, indirectly involved in the epidemiology of many pathogenic bacteria. although several studies have demonstrated intracellular survival of many different bacteria in these species, the extent of such interactions as well as the implications for the epidemiology of the bacterial species involved ... | 2010 | 20056117 |
| in vitro amoebicidal activity of s-nitrosoglutathione and s-nitroso-n-acetylcysteine against trophozoites of acanthamoeba castellanii. | | 2010 | 20085996 |
| [case report: acanthamoeba keratitis]. | acanthamoeba keratitis (ak) is an opportunistic protozoan infection caused by the pathogenic acanthamoeba and associated with soft contact lens wear. if untreated, it can cause serious visual disability. a 23 year-old female wearing soft contact lenses applied to the department of ophthalmology of the aydin adnan menderes university school of medicine, with symptoms of redness, pain and blurred vision of both eyes. she was given a diagnosis of ak on clinical and laboratory grounds. the agent iso ... | 2009 | 20101578 |
| acanthamoeba castellanii: in vitro effects of selected biological, physical and chemical factors. | trophozoites and cysts of free-living acanthamoeba castellanii present a serious risk to human health as causative agents of human diseases such as fatal granulomatous amoebic encephalitis and acanthamoeba keratitis that is reported from various part of the world, also in poland, with increasing frequency, particularly in the contact lens wearers. the amphizoic amoebae are generally extremely resistant to different chemical agents, however, several strains/isolates within a. castellanii may diff ... | 2010 | 20138870 |
| acanthamoeba castellanii: morphological analysis of the interaction with human cornea. | the present study demonstrates that when acanthamoeba castellanii trophozoites are co-cultivated with isolated human corneas, the amoeba can be invasive and cause damage to the intact corneal epithelium without the requirement of previous corneal abrasion. after adhesion, a. castellanii trophozoites migrate between cells forming bumps on the corneal cell layers and reaching bowman s membrane in 3h, although no evidence of cell damage was observed until the phagocytic process was detected. likewi ... | 2010 | 20146924 |
| the autoinducer synthase lqsa and putative sensor kinase lqss regulate phagocyte interactions, extracellular filaments and a genomic island of legionella pneumophila. | the amoebae-resistant opportunistic pathogen legionella pneumophila employs a biphasic life cycle to replicate in host cells and spread to new niches. upon entering the stationary growth phase, the bacteria switch to a transmissive (virulent) state, which involves a complex regulatory network including the lqs gene cluster (lqsa-lqsr-hded-lqss). lqsr is a putative response regulator that promotes host-pathogen interactions and represses replication. the autoinducer synthase lqsa catalyses the pr ... | 2010 | 20148929 |
| the clpp protease homologue is required for the transmission traits and cell division of the pathogen legionella pneumophila. | legionella pneumophila, the intracellular bacterial pathogen that causes legionnaires' disease, exhibit characteristic transmission traits such as elevated stress tolerance, shortened length and virulence during the transition from the replication phase to the transmission phase. clpp, the catalytic core of the clp proteolytic complex, is widely involved in many cellular processes via the regulation of intracellular protein quality. | 2010 | 20167127 |
| 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 ... | 2010 | 20174605 |
| major role for cysteine proteases during the early phase of acanthamoeba castellanii encystment. | acanthamoeba castellanii is a facultative pathogen that has a two-stage life cycle comprising the vegetatively growing trophozoite stage and the dormant cyst stage. cysts are formed when the cell encounters unfavorable conditions, such as environmental stress or food deprivation. due to their rigid double-layered wall, acanthamoeba cysts are highly resistant to antiamoebic drugs. this is problematic as cysts can survive initially successful chemotherapeutic treatment and cause relapse of the dis ... | 2010 | 20190073 |
| evaluation of real-time pcr methods for quantification of acanthamoeba in anthropogenic water and biofilms. | to assess two real-time pcr methods (the riviere and qvarnstrom assays) for environmental acanthamoeba. | 2010 | 20233260 |
| abundant 5s rrna-like transcripts encoded by the mitochondrial genome in amoebozoa. | 5s rrnas are ubiquitous components of prokaryotic, chloroplast, and eukaryotic cytosolic ribosomes but are apparently absent from mitochondrial ribosomes (mitoribosomes) of many eukaryotic groups including animals and fungi. nevertheless, a clearly identifiable, mitochondrion-encoded 5s rrna is present in acanthamoeba castellanii, a member of amoebozoa. during a search for additional mitochondrial 5s rrnas, we detected small abundant rnas in other members of amoebozoa, namely, in the lobose amoe ... | 2010 | 20304999 |
| could insect phagocytic avoidance by entomogenous fungi have evolved via selection against soil amoeboid predators? | the entomopathogenic fungi metarhizium anisopliae and beauveria bassiana are ubiquitously distributed in soils. as insect pathogens they adhere to the insect cuticle and penetrate through to the insect haemocoel using a variety of cuticle-hydrolysing enzymes. once in the insect haemocoel they are able to survive and replicate within, and/or evade, phagocytic haemocyte cells circulating in the haemolymph. the mechanism by which these soil fungi acquire virulence factors for insect infection and i ... | 2010 | 20338910 |
| the legionella pneumophila f-box protein lpp2082 (ankb) modulates ubiquitination of the host protein parvin b and promotes intracellular replication. | the environmental pathogen legionella pneumophila encodes three proteins containing f-box domains and additional protein-protein interaction domains, reminiscent of eukaryotic scf ubiquitin-protein ligases. here we show that the f-box proteins of l. pneumophila strain paris are dot/icm effectors involved in the accumulation of ubiquitinated proteins associated with the legionella-containing vacuole. single, double and triple mutants of the f-box protein encoding genes were impaired in infection ... | 2010 | 20345489 |
| mrna deep sequencing reveals 75 new genes and a complex transcriptional landscape in mimivirus. | mimivirus, a virus infecting acanthamoeba, is the prototype of the mimiviridae, the latest addition to the nucleocytoplasmic large dna viruses. the mimivirus genome encodes close to 1000 proteins, many of them never before encountered in a virus, such as four amino-acyl trna synthetases. to explore the physiology of this exceptional virus and identify the genes involved in the building of its characteristic intracytoplasmic "virion factory," we coupled electron microscopy observations with the m ... | 2010 | 20360389 |
| a legionella pneumophila collagen-like protein encoded by a gene with a variable number of tandem repeats is involved in the adherence and invasion of host cells. | legionella pneumophila is a gram-negative, facultative intracellular pathogen and the causative agent of legionnaires' disease, a severe pneumonia in humans. analysis of the legionella sequenced genomes revealed a gene with a variable number of tandem repeats (vntrs), whose number varies between strains. we examined the strain distribution of this gene among a collection of 108 clinical, environmental and hot spring serotype i strains. twelve variants were identified, but no correlation was obse ... | 2010 | 20370832 |