74 research outputs found

    Emerging Infectious Disease leads to Rapid Population Decline of Common British Birds

    Get PDF
    Emerging infectious diseases are increasingly cited as threats to wildlife, livestock and humans alike. They can threaten geographically isolated or critically endangered wildlife populations; however, relatively few studies have clearly demonstrated the extent to which emerging diseases can impact populations of common wildlife species. Here, we report the impact of an emerging protozoal disease on British populations of greenfinch Carduelis chloris and chaffinch Fringilla coelebs, two of the most common birds in Britain. Morphological and molecular analyses showed this to be due to Trichomonas gallinae. Trichomonosis emerged as a novel fatal disease of finches in Britain in 2005 and rapidly became epidemic within greenfinch, and to a lesser extent chaffinch, populations in 2006. By 2007, breeding populations of greenfinches and chaffinches in the geographic region of highest disease incidence had decreased by 35% and 21% respectively, representing mortality in excess of half a million birds. In contrast, declines were less pronounced or absent in these species in regions where the disease was found in intermediate or low incidence. Also, populations of dunnock Prunella modularis, which similarly feeds in gardens, but in which T. gallinae was rarely recorded, did not decline. This is the first trichomonosis epidemic reported in the scientific literature to negatively impact populations of free-ranging non-columbiform species, and such levels of mortality and decline due to an emerging infectious disease are unprecedented in British wild bird populations. This disease emergence event demonstrates the potential for a protozoan parasite to jump avian host taxonomic groups with dramatic effect over a short time period

    The Vitamin B1 Metabolism of Staphylococcus aureus Is Controlled at Enzymatic and Transcriptional Levels

    Get PDF
    Vitamin B1 is in its active form thiamine pyrophosphate (TPP), an essential cofactor for several key enzymes in the carbohydrate metabolism. Mammals must salvage this crucial nutrient from their diet in order to complement the deficiency of de novo synthesis. In the human pathogenic bacterium Staphylococcus aureus, two operons were identified which are involved in vitamin B1 metabolism. The first operon encodes for the thiaminase type II (TenA), 4-amino-5-hydroxymethyl-2-methylpyrimidine kinase (ThiD), 5-(2-hydroxyethyl)-4-methylthiazole kinase (ThiM) and thiamine phosphate synthase (ThiE). The second operon encodes a phosphatase, an epimerase and the thiamine pyrophosphokinase (TPK). The open reading frames of the individual operons were cloned, their corresponding proteins were recombinantly expressed and biochemically analysed. The kinetic properties of the enzymes as well as the binding of TPP to the in vitro transcribed RNA of the proposed operons suggest that the vitamin B1 homeostasis in S. aureus is strongly regulated at transcriptional as well as enzymatic levels

    Factors associated with parasympathetic activation following exercise in patients with rheumatoid arthritis: a cross-sectional study

    Get PDF
    Background Patients with rheumatoid arthritis (RA) have an increased risk for cardiovascular disease (CVD) with poor parasympathetic function being implicated as an underlying factor. Factors related to parasympathetic function, commonly assessed by heart rate recovery (HRR) following maximal exercise, are currently not known in RA. We aimed to explore the association between HRR with CVD risk factors, inflammatory markers, and wellbeing in patients with RA. Methods Ninety-six RA patients (54.4 ± 12.6 years, 68 % women) completed a treadmill exercise test, during which heart rate (HR) was monitored. HRR1 and HRR2 were defined as the absolute change from HR peak to HRR 1 min post HR peak and 2 min post HR peak, respectively. Cardiorespiratory fitness, CVD risk factors, and serological markers of inflammation were measured in all patients. The Framingham Risk Score (FRS) was used as an assessment of global risk for CVD events, and wellbeing was assessed by questionnaires. Results Mean HRR1 and HRR2 were 29.1 ± 13.2 bpm and 46.4 ± 15.3 bpm, respectively. CVD risk factors as well as most inflammatory markers and measures of wellbeing were inversely correlated with HRR1 and HRR2. Multivariate regression analyses revealed that 27.9 % of the variance in HRR1 and 37.9 % of the variance in HRR2 was explained collectively by CVD risk factors, measures of inflammation, and wellbeing (p = 0.009, p = 0.001 respectively), however no individual measure was independently associated with HRR1 or HRR2. Conclusion Parasympathetic activation was associated with overall CVD risk, arthritis-related burden and wellbeing in patients with RA
    • …
    corecore