RESUMEN
Recent evidence of the occurrence of atypical Chlamydiaceae strains in pigeons, different from the established Chlamydiaceae, requires the development of a specific and rapid detection tool to investigate their prevalence and significance. Here is described a new real-time PCR assay that allows specific detection of atypical Chlamydiaceae from pigeons. The assay has been used to assess the dissemination of these strains in field samples collected from Parisian pigeon populations in 2009. The results suggest a limited dissemination compared to the usually higher prevalence of Chlamydia psittaci that is the main species associated with avian chlamydiosis.
Asunto(s)
Chlamydiaceae/genética , Chlamydiaceae/aislamiento & purificación , Columbidae/microbiología , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Animales , Chlamydiaceae/clasificación , Chlamydiaceae/enzimología , ADN Bacteriano/genética , Genoma Bacteriano/genética , Fosfopiruvato Hidratasa/genética , Filogenia , Reproducibilidad de los ResultadosRESUMEN
One form of immune evasion is a developmental state called "persistence" whereby chlamydial pathogens respond to the host-mediated withdrawal of L-tryptophan (Trp). A sophisticated survival mode of reversible quiescence is implemented. A mechanism has evolved which suppresses gene products necessary for rapid pathogen proliferation but allows expression of gene products that underlie the morphological and developmental characteristics of persistence. This switch from one translational profile to an alternative translational profile of newly synthesized proteins is proposed to be accomplished by maximizing the Trp content of some proteins needed for rapid proliferation (e.g., ADP/ATP translocase, hexose-phosphate transporter, phosphoenolpyruvate [PEP] carboxykinase, the Trp transporter, the Pmp protein superfamily for cell adhesion and antigenic variation, and components of the cell division pathway) while minimizing the Trp content of other proteins supporting the state of persistence. The Trp starvation mechanism is best understood in the human-Chlamydia trachomatis relationship, but the similarity of up-Trp and down-Trp proteomic profiles in all of the pathogenic Chlamydiaceae suggests that Trp availability is an underlying cue relied upon by this family of pathogens to trigger developmental transitions. The biochemically expensive pathogen strategy of selectively increased Trp usage to guide the translational profile can be leveraged significantly with minimal overall Trp usage by (i) regional concentration of Trp residue placements, (ii) amplified Trp content of a single protein that is required for expression or maturation of multiple proteins with low Trp content, and (iii) Achilles'-heel vulnerabilities of complex pathways to high Trp content of one or a few enzymes.
Asunto(s)
Proteínas Bacterianas/biosíntesis , Chlamydiaceae/inmunología , Triptófano/metabolismo , Proteínas Bacterianas/genética , Infecciones por Chlamydia/metabolismo , Infecciones por Chlamydia/microbiología , Chlamydiaceae/enzimología , Chlamydiaceae/metabolismo , Humanos , ProteómicaRESUMEN
In Chlamydiaceae, the nucleotide sequence between the 5S rRNA gene and the gene for subunit F of the Na(+)-translocating NADH-quinone reductase (nqrF or dmpP) has varied lengths and gene contents. We analyzed this site in 45 Chlamydiaceae strains having diverse geographical and pathological origins and including members of all nine species.
Asunto(s)
Chlamydiaceae/enzimología , Genoma Bacteriano , NADH NADPH Oxidorreductasas/genética , Proteínas Bacterianas , Secuencia de Bases , Chlamydiaceae/genética , Flavoproteínas , Variación Genética , Datos de Secuencia Molecular , NADH NADPH Oxidorreductasas/químicaRESUMEN
Membrane proteins that transport ATP and ADP have been identified in mitochondria, plastids, and obligate intracellular parasites. The mitochondrial ATP/ADP transporters are derived from a broad-specificity transport family of eukaryotic origin, whereas the origin of the plastid/parasite ATP/ADP translocase is more elusive. Here we present the sequences of five genes coding for ATP/ADP translocases from four species of Rickettsia. The results are consistent with an early duplication and divergence of the five ATP/ADP translocases within the rickettsial lineage. A comparison of the phylogenetic depths of the mitochondrial and the plastid/parasite ATP/ADP translocases indicates a deep origin for both transporters. The results provide no evidence for a recent acquisition of the ATP/ADP transporters in Rickettsia via horizontal gene transfer, as previously suggested. A possible function of the two types of ATP/ADP translocases was to allow switches between glycolysis and aerobic respiration in the early eukaryotic cell and its endosymbiont.
Asunto(s)
Translocasas Mitocondriales de ADP y ATP/genética , Filogenia , Plastidios/enzimología , Rickettsia/enzimología , Secuencia de Aminoácidos , Proteínas Bacterianas/genética , Chlamydiaceae/enzimología , Chlamydiaceae/genética , Células Eucariotas/enzimología , Células Eucariotas/microbiología , Evolución Molecular , Transferencia de Gen Horizontal , Interacciones Huésped-Parásitos , Mitocondrias/enzimología , Mitocondrias/genética , Datos de Secuencia Molecular , Plastidios/genética , Rickettsia/genética , Rickettsia rickettsii/enzimología , Rickettsia rickettsii/genética , Rickettsia typhi , Análisis de Secuencia , Homología de Secuencia de AminoácidoRESUMEN
BACKGROUND: Complete genomic sequences of closely related organisms, such as the chlamydiae, afford the opportunity to assess significant strain differences against a background of many shared characteristics. The chlamydiae are ubiquitous intracellular parasites that are important pathogens of humans and other organisms. Tryptophan limitation caused by production of interferon-gamma by the host and subsequent induction of indoleamine dioxygenase is a key aspect of the host-parasite interaction. It appears that the chlamydiae have learned to recognize tryptophan depletion as a signal for developmental remodeling. The consequent non-cultivable state of persistence can be increasingly equated to chronic disease conditions. RESULTS: The genes encoding enzymes of tryptophan biosynthesis were the focal point of this study. Chlamydophila psittaci was found to possess a compact operon containing PRPP synthase, kynureninase, and genes encoding all but the first step of tryptophan biosynthesis. All but one of the genes exhibited translational coupling. Other chlamydiae (Chlamydia trachomatis, C. muridarum and Chlamydophila pneumoniae) lack genes encoding PRPP synthase, kynureninase, and either lack tryptophan-pathway genes altogether or exhibit various stages of reductive loss. The origin of the genes comprising the trp operon does not seem to have been from lateral gene transfer. CONCLUSIONS: The factors that accommodate the transition of different chlamydial species to the persistent (chronic) state of pathogenesis include marked differences in strategies deployed to obtain tryptophan from host resources. C. psittaci appears to have a novel mechanism for intercepting an early intermediate of tryptophan catabolism and recycling it back to tryptophan. In effect, a host-parasite metabolic mosaic has evolved for tryptophan recycling.
Asunto(s)
Chlamydiaceae/genética , Chlamydiaceae/metabolismo , Proteínas de Escherichia coli , Evolución Molecular , Variación Genética/genética , Operón/genética , Triptófano/metabolismo , Proteínas Bacterianas/genética , Toxinas Bacterianas/genética , Transporte Biológico Activo/genética , Chlamydia muridarum/enzimología , Chlamydia muridarum/genética , Chlamydia muridarum/metabolismo , Chlamydia trachomatis/enzimología , Chlamydia trachomatis/genética , Chlamydia trachomatis/metabolismo , Chlamydiaceae/enzimología , Chlamydophila pneumoniae/enzimología , Chlamydophila pneumoniae/genética , Chlamydophila pneumoniae/metabolismo , Chlamydophila psittaci/enzimología , Chlamydophila psittaci/genética , Chlamydophila psittaci/metabolismo , Transferencia de Gen Horizontal/genética , Genes Bacterianos/genética , Genes Reguladores/genética , Genes Reguladores/fisiología , Hidrolasas/genética , Quinurenina/metabolismo , Proteínas Represoras/genética , Proteínas Represoras/fisiología , Ribosa-Fosfato Pirofosfoquinasa/genética , Serina/metabolismoRESUMEN
The waaA gene encoding the essential, lipopolysaccharide (LPS)-specific 3-deoxy-Dmanno-oct-2-ulosonic acid (Kdo) transferase was inactivated in the chromosome of a heptosyltransferase I and II deficient Escherichia coli K-12 strain by insertion of gene expression cassettes encoding the waaA genes of Chlamydia trachomatis, Chlamydophila pneumoniae or Chlamydophila psittaci. The three chlamydial Kdo transferases were able to complement the knockout mutation without changing the growth or multiplication behaviour. The LPS of the mutants were serologically and structurally characterized in comparison to the LPS of the parent strain using compositional analyses, high performance anion exchange chromatography, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and specific monoclonal antibodies. The data show that chlamydial Kdo transferases can replace in E. coli K-12 the host's Kdo transferase and retain the product specificities described in their natural background. In addition, we unequivocally proved that WaaA from C. psittaci transfers predominantly four Kdo residues to lipid A, forming a branched tetrasaccharide with the structure alpha-Kdo-(2-->8)-[alpha-Kdo-(2-->4)]-alpha-Kdo-(2-->4)-alpha-Kdo.
