64 research outputs found

    Comparative analyses of transport proteins encoded within the genomes of Leptospira species

    Full text link
    Select species of the bacterial genus Leptospira are causative agents of leptospirosis, an emerging global zoonosis affecting nearly one million people worldwide annually. We examined two Leptospira pathogens, L. interrogans serovar Lai str. 56601 and L. borgpetersenii serovar Hardjo-bovis str. L550, as well as the free-living leptospiral saprophyte, L. biflexa serovar Patoc str. ā€˜Patoc 1 (Ames)ā€™. The transport proteins of these leptospires were identified and compared using bioinformatics to gain an appreciation for which proteins may be related to pathogenesis and saprophytism. L. biflexa possesses a disproportionately high number of secondary carriers for metabolite uptake and environmental adaptability as well as an increased number of inorganic cation transporters providing ionic homeostasis and effective osmoregulation in a rapidly changing environment. L. interrogans and L. borgpetersenii possess far fewer transporters, but those that they all have are remarkably similar, with near-equivalent representation in most transporter families. These two Leptospira pathogens also possess intact sphingomyelinases, holins, and virulence-related outer membrane porins. These virulence-related factors, in conjunction with decreased transporter substrate versatility, indicate that pathogenicity arose in Leptospira correlating to progressively narrowing ecological niches and the emergence of a limited set of proteins responsible for host invasion. The variability of host tropism and mortality rates by infectious leptospires suggests that small differences in individual sets of proteins play important physiological and pathological roles

    Comparative genomic analyses of transport proteins encoded within the genomes of Leptospira species

    Full text link
    Select species of the bacterial genus Leptospira are causative agents of leptospirosis, an emerging global zoonosis affecting nearly one million people worldwide annually. We examined two Leptospira pathogens, L. interrogans serovar Lai str. 56601 and L. borgpetersenii serovar Hardjo-bovis str. L550, as well as the free-living leptospiral saprophyte, L. biflexa serovar Patoc str. ā€˜Patoc 1 (Ames)ā€™. The transport proteins of these leptospires were identified and compared using bioinformatics to gain an appreciation for which proteins may be related to pathogenesis and saprophytism. L. biflexa possesses a disproportionately high number of secondary carriers for metabolite uptake and environmental adaptability as well as an increased number of inorganic cation transporters providing ionic homeostasis and effective osmoregulation in a rapidly changing environment. L. interrogans and L. borgpetersenii possess far fewer transporters, but those that they have are remarkably similar, with near-equivalent representation in most transporter families. These two Leptospira pathogens also possess intact sphingomyelinases, holins, and virulence-related outer membrane porins. These virulence-related factors, in conjunction with decreased transporter substrate versatility, indicate that pathogenicity was accompanied by progressively narrowing ecological niches and the emergence of a limited set of proteins responsible for host invasion. The variability of host tropism and mortality rates by infectious leptospires suggests that small differences in individual sets of proteins play important physiological and pathological roles

    THE ATOM-PROBE WITH A FIELD EMISSION ELECTRON SPECTROMETER

    No full text
    The basic imaging process of FIM and STM is electron tunneling. Therefore, the clarification of tunneling properties of individual surface atoms is an essential requirement for the deduction of a true topography from a depicted image. Accordingly, a field emission electron energy analyzer was mounted behind the imaging screen of an atomprobe in order to clarify the tunneling property of a surface atom. The advantage of this arrangement is the ability to mass analyze apex atoms and examine the effect of adsorbed contaminants on the tunneling property. The preliminary examination indicates that the sensitivity and energy resolution of the analyzer are high enough for the study of adsorbed hydrogen on silicon
    • ā€¦
    corecore