| a genomic island present along the bacterial chromosome of the parachlamydiaceae uwe25, an obligate amoebal endosymbiont, encodes a potentially functional f-like conjugative dna transfer system. | the genome of protochlamydia amoebophila uwe25, a parachlamydia-related endosymbiont of free-living amoebae, was recently published, providing the opportunity to search for genomic islands (gis). | 2004 | 15615594 |
| l,l-diaminopimelate aminotransferase, a trans-kingdom enzyme shared by chlamydia and plants for synthesis of diaminopimelate/lysine. | the synthesis of meso-diaminopimelic acid (m-dap) in bacteria is essential for both peptidoglycan and lysine biosynthesis. from genome sequencing data, it was unclear how bacteria of the chlamydiales order would synthesize m-dap in the absence of dapd, dapc, and dape, which are missing from the genome. here, we assessed the biochemical capacity of chlamydia trachomatis serovar l2 to synthesize m-dap. expression of the chlamydial asd, dapb, and dapf genes in the respective escherichia coli m-dap ... | 2006 | 17093042 |
| analyses of six homologous proteins of protochlamydia amoebophila uwe25 encoded by large gc-rich genes (lgr): a model of evolution and concatenation of leucine-rich repeats. | along the chromosome of the obligate intracellular bacteria protochlamydia amoebophila uwe25, we recently described a genomic island pam100g. it contains a tra unit likely involved in conjugative dna transfer and lgre, a 5.6-kb gene similar to five others of p. amoebophila: lgra to lgrd, lgrf. we describe here the structure, regulation and evolution of these proteins termed lgrs since encoded by "large g+c-rich" genes. | 2007 | 18021397 |
| raman microspectroscopy reveals long-term extracellular activity of chlamydiae. | the phylum chlamydiae consists exclusively of obligate intracellular bacteria. some of them are formidable pathogens of humans, while others occur as symbionts of amoebae. these genetically intractable bacteria possess a developmental cycle consisting of replicative reticulate bodies and infectious elementary bodies, which are believed to be physiologically inactive. confocal raman microspectroscopy was applied to differentiate between reticulate bodies and elementary bodies of protochlamydia am ... | 2010 | 20545842 |
| parachlamydia acanthamoebae in domestic cats with and without corneal disease. | corneal samples of cats with and without corneal diseases were screened with a pan-chlamydiales pcr and specific pcrs for parachlamydia, protochlamydia, chlamydophila felis, acanthamoeba and feline herpesviruses (fhv-1). several corneal samples tested positive for parachlamydia and related chlamydiales, indicating cat exposure to these intracellular bacteria. | 2010 | 20618801 |
| inclusion membrane proteins of protochlamydia amoebophila uwe25 reveal a conserved mechanism for host cell interaction among the chlamydiae. | chlamydiae are a group of obligate intracellular bacteria comprising several important human pathogens. inside the eukaryotic cell, chlamydiae remain within a host-derived vesicular compartment, termed the inclusion. they modify the inclusion membrane through insertion of unique proteins, which are involved in interaction with and manipulation of the host cell. among chlamydiae, inclusion membrane proteins have been exclusively found in members of the family chlamydiaceae, which predominantly in ... | 2010 | 20675479 |
| lack of effective anti-apoptotic activities restricts growth of parachlamydiaceae in insect cells. | the fundamental role of programmed cell death in host defense is highlighted by the multitude of anti-apoptotic strategies evolved by various microbes, including the well-known obligate intracellular bacterial pathogens chlamydia trachomatis and chlamydia (chlamydophila) pneumoniae. as inhibition of apoptosis is assumed to be essential for a successful infection of humans by these chlamydiae, we analyzed the anti-apoptotic capacity of close relatives that occur as symbionts of amoebae and might ... | 2012 | 22253735 |
| comprehensive in silico prediction and analysis of chlamydial outer membrane proteins reflects evolution and life style of the chlamydiae. | chlamydiae are obligate intracellular bacteria comprising some of the most important bacterial pathogens of animals and humans. although chlamydial outer membrane proteins play a key role for attachment to and entry into host cells, only few have been described so far. we developed a comprehensive, multiphasic in silico approach, including the calculation of clusters of orthologues, to predict outer membrane proteins using conservative criteria. we tested this approach using escherichia coli (po ... | 2009 | 20040079 |
| evidence that the intra-amoebal legionella drancourtii acquired a sterol reductase gene from eukaryotes. | free-living amoebae serve as a natural reservoir for some bacteria that have evolved into "amoeba-resistant" bacteria. among these, some are strictly intra-amoebal, such as candidatus "protochlamydia amoebophila" (candidatus "p. amoebophila"), whose genomic sequence is available. we sequenced the genome of legionella drancourtii (l. drancourtii), another recently described intra-amoebal bacterium. by comparing these two genomes with those of their closely related species, we were able to study t ... | 2009 | 19327142 |
| protochlamydia naegleriophila as etiologic agent of pneumonia. | using ameba coculture, we grew a naegleria endosymbiont. phenotypic, genetic, and phylogenetic analyses supported its affiliation as protochlamydia naegleriophila sp. nov. we then developed a specific diagnostic pcr for protochlamydia spp. when applied to bronchoalveolar lavages, results of this pcr were positive for 1 patient with pneumonia. further studies are needed to assess the role of protochlamydia spp. in pneumonia. | 2008 | 18258101 |
| emerging role of chlamydia and chlamydia-like organisms in adverse pregnancy outcomes. | this review considers the roles of chlamydia spp. and newly identified chlamydia-like organisms in miscarriage, stillbirths and preterm labour in both animals and humans. | 2008 | 18192789 |
| genome sequence of rickettsia bellii illuminates the role of amoebae in gene exchanges between intracellular pathogens. | the recently sequenced rickettsia felis genome revealed an unexpected plasmid carrying several genes usually associated with dna transfer, suggesting that ancestral rickettsiae might have been endowed with a conjugation apparatus. here we present the genome sequence of rickettsia bellii, the earliest diverging species of known rickettsiae. the 1,552,076 base pair-long chromosome does not exhibit the colinearity observed between other rickettsia genomes, and encodes a complete set of putative con ... | 2006 | 16703114 |
| blast screening of chlamydial genomes to identify signature proteins that are unique for the chlamydiales, chlamydiaceae, chlamydophila and chlamydia groups of species. | chlamydiae species are of much importance from a clinical viewpoint. their diversity both in terms of their numbers as well as clinical involvement are presently believed to be significantly underestimated. the obligate intracellular nature of chlamydiae has also limited their genetic and biochemical studies. thus, it is of importance to develop additional means for their identification and characterization. | 2006 | 16436211 |
| building the invisible wall: updating the chlamydial peptidoglycan anomaly. | the existence of peptidoglycan (pg) in chlamydiae has long been debated. genome sequencing of members of the chlamydiaceae family and protochlamydia amoebophila has uncovered a nearly complete pathway for pg synthesis in these organisms. the recent use of microarray and proteomic analysis methods has revealed that pg synthesis genes are expressed primarily during reticulate body development and division. furthermore, key genes in the chlamydial pg synthesis pathway encode functional pg synthesis ... | 2006 | 16413190 |
| 'candidatus protochlamydia amoebophila', an endosymbiont of acanthamoeba spp. | the obligately intracellular coccoid bacterium uwe25, a symbiont of acanthamoeba spp., was previously identified as being related to chlamydiae based upon the presence of a chlamydia-like developmental cycle and its 16s rrna gene sequence. analysis of its complete genome sequence demonstrated that uwe25 shows many characteristic features of chlamydiae, including dependency on host-derived metabolites, composition of the cell envelope and the ability to thrive as an energy parasite within the cel ... | 2005 | 16166679 |
| amoebal host-range, host-free survival and disinfection susceptibility of environmental chlamydiae as compared to chlamydia trachomatis. | the term "chlamydia-like organisms" encompasses obligate intra-cellular bacterial species phylogenetically close to chlamydiaceae. most are associated with free-living amoebae and several could be responsible for respiratory tract infections and abortion in human and animals. despite increasing concern about their pathogenic role, the prevalence, biodiversity, and ecology of chlamydia-related bacteria still remain largely unknown. in this study, six members of the chlamydiales were tested, inclu ... | 2011 | 22141597 |
| proteomic analysis of the outer membrane of protochlamydia amoebophila elementary bodies. | chlamydiae are obligate intracellular bacteria, comprising some of the most important bacterial pathogens of animals and humans. during their unique developmental cycle they have to attach to and enter their eukaryotic host cells, a process mediated by proteins in the chlamydial outer membrane. so far the only experimental data for chlamydial outer membrane proteins are available from members of the chlamydiaceae, a family comprising exclusively human and animal pathogens. to get further insight ... | 2010 | 21105008 |
| diversity of 16s rrna genes within individual prokaryotic genomes. | analysis of intragenomic variation of 16s rrna genes is a unique approach to examining the concept of ribosomal constraints on rrna genes; the degree of variation is an important parameter to consider for estimation of the diversity of a complex microbiome in the recently initiated human microbiome project (http://nihroadmap.nih.gov/hmp). the current genbank database has a collection of 883 prokaryotic genomes representing 568 unique species, of which 425 species contained 2 to 15 copies of 16s ... | 2010 | 20418441 |
| genome analysis of microorganisms living in amoebae reveals a melting pot of evolution. | abstract amoebae-resistant microorganisms exhibit a specific lifestyle. unlike allopatric specialized intracellular pathogens, they have not specialized because they infect the amoebae via amoebal attack and present a sympatric lifestyle with species from different phyla. in this review, we compare the genomes from bacteria (legionella pneumophila, legionella drancourtii, candidatus'protochlamydia amoebophila,'rickettsia bellii, candidatus'amoebophilus asiaticus') and a virus (mimivirus) that mu ... | 2010 | 20132312 |
| parachlamydia acanthamoebae, an emerging agent of pneumonia. | parachlamydia acanthamoebae is a chlamydia-like organism that easily grows within acanthamoeba spp. thus, it probably uses these widespread free-living amoebae as a replicative niche, a cosmopolite aquatic reservoir and a vector. a potential role of p. acanthamoebae as an agent of lower respiratory tract infection was initially suggested by its isolation within an acanthamoeba sp. recovered from the water of a humidifier during the investigation of an outbreak of fever. additional serological an ... | 2009 | 19220336 |
| chlamydiae has contributed at least 55 genes to plantae with predominantly plastid functions. | the photosynthetic organelle (plastid) originated via primary endosymbiosis in which a phagotrophic protist captured and harnessed a cyanobacterium. the plastid was inherited by the common ancestor of the red, green (including land plants), and glaucophyte algae (together, the plantae). despite the critical importance of primary plastid endosymbiosis, its ancient derivation has left behind very few "footprints" of early key events in organelle genesis. | 2008 | 18493612 |
| chlamydia-like bacteria in respiratory samples of community-acquired pneumonia patients. | chlamydia-like bacteria, obligate intracellular relatives of chlamydia trachomatis and chlamydophila pneumoniae, are widely distributed in nature. using a two-step nested and semi-nested pcr approach targeting the 16s rrna gene, we found dna of chlamydia-like bacteria in respiratory samples from patients with community-acquired pneumonia. of 387 cases tested, four (1.03%) tested positive if only sequences showing less than 99.9% 16s rrna gene sequence similarity to known chlamydiae were consider ... | 2008 | 18312573 |
| multi locus sequence typing of chlamydiales: clonal groupings within the obligate intracellular bacteria chlamydia trachomatis. | the obligate intracellular growing bacterium chlamydia trachomatis causes diseases like trachoma, urogenital infection and lymphogranuloma venereum with severe morbidity. several serovars and genotypes have been identified, but these could not be linked to clinical disease or outcome. the related chlamydophila pneumoniae, of which no subtypes are recognized, causes respiratory infections worldwide. we developed a multi locus sequence typing (mlst) scheme to understand the population genetic stru ... | 2008 | 18307777 |
| enlightening energy parasitism by analysis of an atp/adp transporter from chlamydiae. | energy parasitism by atp/adp transport proteins is an essential, common feature of intracellular bacteria such as chlamydiae and rickettsiae, which are major pathogens of humans. although several atp/adp transport proteins have so far been characterized, some fundamental questions regarding their function remained unaddressed. in this study, we focused on the detailed biochemical analysis of a representative atp/adp transporter (pamntt1), from the amoeba symbiont protochlamydia amoebophila (uwe2 ... | 2007 | 17760504 |
| did an ancient chlamydial endosymbiosis facilitate the establishment of primary plastids? | ancient endosymbioses are responsible for the origins of mitochondria and plastids, and they contribute to the divergence of several major eukaryotic groups. although chlamydiae, a group of obligate intracellular bacteria, are not found in plants, an unexpected number of chlamydial genes are most similar to plant homologs, which, interestingly, often contain a plastid-targeting signal. this observation has prompted several hypotheses, including gene transfer between chlamydiae and plant-related ... | 2007 | 17547748 |
| tapping the nucleotide pool of the host: novel nucleotide carrier proteins of protochlamydia amoebophila. | protochlamydia amoebophila uwe25 is related to the chlamydiaceae comprising major pathogens of humans, but thrives as obligate intracellular symbiont in the protozoan host acanthamoeba sp. the genome of p. amoebophila encodes five paralogous carrier proteins belonging to the nucleotide transporter (ntt) family. here we report on three p. amoebophila ntt isoforms, pamntt2, pamntt3 and pamntt5, which possess several conserved amino acid residues known to be critical for nucleotide transport. we de ... | 2006 | 16796686 |
| [Environmental Chlamydiae with medical significance]. | The molecular biological analysis of a chlamydia-like bacterium from Acanthamoeba sp., originated from the nasal mucosa of a female subject, led to the description of the new species Parachlamydia acanthamoebae. It provided the basis for establishing its own family Parachlamydiaceae, which was genetically separated from the traditional Chlamydiaceae. In the following years other chlamydia-like bacteria, replicating within different free-living amoeba species, have been observed. Due to their clo ... | 2011 | 21971886 |
| chlamydia-related bacteria in respiratory samples in finland. | chlamydiarelated bacteria, new members of the order chlamydiales, are suggested to be associated with respiratory disease. we used real-time pcr to investigate the prevalence of parachlamydia acanthamoebae, protochlamydia spp., rhabdochlamydia spp., simkania negevensis and waddlia chondrophila in samples taken from patients with suspected respiratory tract infections. of the 531 samples analyzed, the subset of 136 samples contained 16 (11.8%) samples positive for rhabdochlamydia spp. dna. p. aca ... | 2011 | 21612765 |
| proteomic analysis reveals a virtually complete set of proteins for translation and energy generation in elementary bodies of the amoeba symbiont protochlamydia amoebophila. | chlamydiae belong to the most successful intracellular bacterial pathogens. they display a complex developmental cycle and an extremely broad host spectrum ranging from vertebrates to protozoa. the family chlamydiaceae comprises exclusively well-known pathogens of humans and animals, whereas the members of its sister group, the parachlamydiaceae, naturally occur as symbionts of free-living amoebae. comparative analysis of these two groups provides valuable insights into chlamydial evolution and ... | 2011 | 21500343 |
| proteomic analysis of the outer membrane of protochlamydia amoebophila elementary bodies. | chlamydiae are obligate intracellular bacteria, comprising some of the most important bacterial pathogens of animals and humans. during their unique developmental cycle they have to attach to and enter their eukaryotic host cells, a process mediated by proteins in the chlamydial outer membrane. so far the only experimental data for chlamydial outer membrane proteins are available from members of the chlamydiaceae, a family comprising exclusively human and animal pathogens. to get further insight ... | 2010 | 21136591 |