Clocking the Lyme Spirochete

In order to clear the body of infecting spirochetes, phagocytic cells must be able to get hold of them. In real-time phase-contrast videomicroscopy we were able to measure the speed of Borrelia burgdorferi (Bb), the Lyme spirochete, moving back and forth across a platelet to which it was tethered. Its mean crossing speed was 1,636 µm/min (N = 28), maximum, 2800 µm/min (N = 3). This is the fastest speed recorded for a spirochete, and upward of two orders of magnitude above the speed of a human neutrophil, the fastest cell in the body. This alacrity and its interpretation, in an organism with bidirectional motor capacity, may well contribute to difficulties in spirochete clearance by the host

Oporezivanje digitalnih usluga u republici Hrvatskoj : završni rad

Rad ne sadrži sažetak

The Complete Genome Sequence of ‘Candidatus Liberibacter solanacearum’, the Bacterium Associated with Potato Zebra Chip Disease

Zebra Chip (ZC) is an emerging plant disease that causes aboveground decline of potato shoots and generally results in unusable tubers. This disease has led to multi-million dollar losses for growers in the central and western United States over the past decade and impacts the livelihood of potato farmers in Mexico and New Zealand. ZC is associated with ‘Candidatus Liberibacter solanacearum’, a fastidious alpha-proteobacterium that is transmitted by a phloem-feeding psyllid vector, Bactericera cockerelli Sulc. Research on this disease has been hampered by a lack of robust culture methods and paucity of genome sequence information for ‘Ca. L. solanacearum’. Here we present the sequence of the 1.26 Mbp metagenome of ‘Ca. L. solanacearum’, based on DNA isolated from potato psyllids. The coding inventory of the ‘Ca. L. solanacearum’ genome was analyzed and compared to related Rhizobiaceae to better understand ‘Ca. L. solanacearum’ physiology and identify potential targets to develop improved treatment strategies. This analysis revealed a number of unique transporters and pathways, all potentially contributing to ZC pathogenesis. Some of these factors may have been acquired through horizontal gene transfer. Taxonomically, ‘Ca. L. solanacearum’ is related to ‘Ca. L. asiaticus’, a suspected causative agent of citrus huanglongbing, yet many genome rearrangements and several gene gains/losses are evident when comparing these two Liberibacter. species. Relative to ‘Ca. L. asiaticus’, ‘Ca. L. solanacearum’ probably has reduced capacity for nucleic acid modification, increased amino acid and vitamin biosynthesis functionalities, and gained a high-affinity iron transport system characteristic of several pathogenic microbes

Associations of Perceived Social and Physical Environmental Supports With Physical Activity and Walking Behavior

We evaluated perceived social and environmental supports for physical activity and walking using multivariable modeling. Perceptions were obtained on a sample of households in a southeastern county. Respondents were classified according to physical activity levels and walking behaviors. Respondents who had good street lighting; trusted their neighbors; and used private recreational facilities, parks, playgrounds, and sports fields were more likely to be regularly active. Perceiving neighbors as being active, having access to sidewalks, and using malls were associated with regular walking

Environmental measures of physical activity supports: Perception versus reality

Background Perceptions of the environment and physical activity have been associated using survey methods, yet little is known about the validity of environmental surveys. In this study, perceptions of the environment at neighborhood and community levels were assessed (1) to determine validity by comparing respondent perceptions to objective measures and (2) to determine test–retest reliability of the survey. Methods A telephone survey was administered to a stratified sample of Sumter County, South Carolina adults. Respondents’ home addresses were mapped using a geographic information system (GIS) (n =1112). As an indicator of validity, kappa statistics were used to measure agreement between perceptions and objective measures identified at neighborhood and community levels using GIS. A second survey in an independent sample (n=408) assessed test–retest reliability. Results When assessing perceptions of environmental and physical activity in a defined geographic area, validity and reliability for neighborhood survey items were κ=−0.02 to 0.37 and RHO=0.42 to 0.74, and for community survey items were κ=−0.07 to 0.25 and RHO=0.28 to 0.56. Conclusions Although causality between perception of access and safety and actual physical activity level cannot be assumed, those meeting national physical activity guidelines or reporting some physical activity demonstrated greatest agreement with access to recreation facilities, while those not meeting the guidelines demonstrated greater agreement with safety of recreation facilities. Factors such as distance and behavior may explain differences in perceptions at neighborhood and community levels. Using local environments with short distances in survey methods improves validity and reliability of results