Type III flagellar protein export and flagellar assembly

AbstractBacterial flagella, unlike eukaryotic flagella, are largely external to the cell and therefore many of their subunits have to be exported. Export is ATP-driven. In Salmonella, the bacterium on which this chapter largely focuses, the apparatus responsible for flagellar protein export consists of six membrane components, three soluble components and several substrate-specific chaperones. Other flagellated eubacteria have similar systems. The membrane components of the export apparatus are housed within the flagellar basal body and deliver their substrates into a channel or lumen in the nascent structure from which point they diffuse to the far end and assemble. Both on the basis of sequence similarities of several components and structural similarities, the flagellar protein export systems clearly belong to the type III superfamily, whose other members are responsible for secretion of virulence factors by many species of pathogenic bacteria

Risk of pregnancy-related hypertension within 5 years of exposure to drinking water contaminated with Escherichia coli O157:H7

The authors evaluated the risk for pregnancy-related hypertension among previously healthy women who conceived within 5 years of exposure to drinking water contaminated with Escherichia coli O157.H7 in Walkerton, Canada (2000). Chronic hypertension was defined as systolic/diastolic blood pressure ≥140/90 mm Hg before 20 weeks gestation; gestational hypertension was defined as new onset systolic/diastolic blood pressure ≥140/90 mm Hg ≥20 weeks gestation. The incidence of hypertension was compared between women who were asymptomatic during the outbreak to those who experienced acute gastroenteritis. Blood pressure data were available for 135 of 148 eligible pregnancies. The adjusted relative risks for chronic and gestational hypertension were 1.5 (95% confidence interval [CI]: 0.3-7.7) and 1.0 (95% CI: 0.4-2.5), respectively. Mean arterial pressure before 20 weeks gestation was 2.7 mm Hg higher in women who had acute gastroenteritis (95% CI: 0.05-5.4). A trend toward higher chronic hypertension and mean arterial pressure in early pregnancy was observed among women who experienced gastroenteritis after exposure to bacterially-contaminated drinking water. © 2010 Wiley Periodicals, Inc

Ten years of major equestrian injury: are we addressing functional outcomes?

YesFunding provided by the Open Access Authors Fund

Phosphorylation of GFAP is associated with injury in the neonatal pig hypoxic-ischemic brain

Glial fibrillary acidic protein (GFAP) is an intermediate filament protein expressed in the astrocyte cytoskeleton that plays an important role in the structure and function of the cell. GFAP can be phosphorylated at six serine (Ser) or threonine (Thr) residues but little is known about the role of GFAP phosphorylation in physiological and pathophysiological states. We have generated antibodies against two phosphorylated GFAP (pGFAP) proteins: p8GFAP, where GFAP is phosphorylated at Ser-8 and p13GFAP, where GFAP is phosphorylated at Ser-13. We examined p8GFAP and p13GFAP expression in the control neonatal pig brain and at 24 and 72 h after an hypoxic-ischemic (HI) insult. Immunohistochemistry demonstrated pGFAP expression in astrocytes with an atypical cytoskeletal morphology, even in control brains. Semi-quantitative western blotting revealed that p8GFAP expression was significantly increased at 24 h post-insult in HI animals with seizures in frontal, parietal, temporal and occipital cortices. At 72 h post-insult, p8GFAP and p13GFAP expression were significantly increased in HI animals with seizures in brain regions that are vulnerable to cellular damage (cortex and basal ganglia), but no changes were observed in brain regions that are relatively spared following an HI insult (brain stem and cerebellum). Increased pGFAP expression was associated with poor neurological outcomes such as abnormal encephalography and neurobehaviour, and increased histological brain damage. Phosphorylation of GFAP may play an important role in astrocyte remodelling during development and disease and could potentially contribute to the plasticity of the central nervous system

Malaria in Africa: Vector Species' Niche Models and Relative Risk Maps

A central theoretical goal of epidemiology is the construction of spatial models of disease prevalence and risk, including maps for the potential spread of infectious disease. We provide three continent-wide maps representing the relative risk of malaria in Africa based on ecological niche models of vector species and risk analysis at a spatial resolution of 1 arc-minute (9 185 275 cells of approximately 4 sq km). Using a maximum entropy method we construct niche models for 10 malaria vector species based on species occurrence records since 1980, 19 climatic variables, altitude, and land cover data (in 14 classes). For seven vectors (Anopheles coustani, A. funestus, A. melas, A. merus, A. moucheti, A. nili, and A. paludis) these are the first published niche models. We predict that Central Africa has poor habitat for both A. arabiensis and A. gambiae, and that A. quadriannulatus and A. arabiensis have restricted habitats in Southern Africa as claimed by field experts in criticism of previous models. The results of the niche models are incorporated into three relative risk models which assume different ecological interactions between vector species. The “additive” model assumes no interaction; the “minimax” model assumes maximum relative risk due to any vector in a cell; and the “competitive exclusion” model assumes the relative risk that arises from the most suitable vector for a cell. All models include variable anthrophilicity of vectors and spatial variation in human population density. Relative risk maps are produced from these models. All models predict that human population density is the critical factor determining malaria risk. Our method of constructing relative risk maps is equally general. We discuss the limits of the relative risk maps reported here, and the additional data that are required for their improvement. The protocol developed here can be used for any other vector-borne disease

Report from the Annual Conference of the British Society of Echocardiography, November 2017, Edinburgh International Conference Centre, Edinburgh

No abstract available

The Bacterial Flagellum: Reversible Rotary Propellor and Type III Export Apparatus

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