Effects of temperature on the transmission of Yersinia Pestis by the flea, Xenopsylla Cheopis, in the late phase period

<p>Abstract</p> <p>Background</p> <p>Traditionally, efficient flea-borne transmission of <it>Yersinia pestis</it>, the causative agent of plague, was thought to be dependent on a process referred to as blockage in which biofilm-mediated growth of the bacteria physically blocks the flea gut, leading to the regurgitation of contaminated blood into the host. This process was previously shown to be temperature-regulated, with blockage failing at temperatures approaching 30°C; however, the abilities of fleas to transmit infections at different temperatures had not been adequately assessed. We infected colony-reared fleas of <it>Xenopsylla cheopis </it>with a wild type strain of <it>Y. pestis </it>and maintained them at 10, 23, 27, or 30°C. Naïve mice were exposed to groups of infected fleas beginning on day 7 post-infection (p.i.), and every 3-4 days thereafter until day 14 p.i. for fleas held at 10°C, or 28 days p.i. for fleas held at 23-30°C. Transmission was confirmed using <it>Y. pestis</it>-specific antigen or antibody detection assays on mouse tissues.</p> <p>Results</p> <p>Although no statistically significant differences in per flea transmission efficiencies were detected between 23 and 30°C, efficiencies were highest for fleas maintained at 23°C and they began to decline at 27 and 30°C by day 21 p.i. These declines coincided with declining median bacterial loads in fleas at 27 and 30°C. Survival and feeding rates of fleas also varied by temperature to suggest fleas at 27 and 30°C would be less likely to sustain transmission than fleas maintained at 23°C. Fleas held at 10°C transmitted <it>Y. pestis </it>infections, although flea survival was significantly reduced compared to that of uninfected fleas at this temperature. Median bacterial loads were significantly higher at 10°C than at the other temperatures.</p> <p>Conclusions</p> <p>Our results suggest that temperature does not significantly effect the per flea efficiency of <it>Y. pestis </it>transmission by <it>X. cheopis</it>, but that temperature is likely to influence the dynamics of <it>Y. pestis </it>flea-borne transmission, perhaps by affecting persistence of the bacteria in the flea gut or by influencing flea survival. Whether <it>Y. pestis </it>biofilm production is important for transmission at different temperatures remains unresolved, although our results support the hypothesis that blockage is not necessary for efficient transmission.</p

Motherhood: Female Perspectives and Experiences of Being a Parent with ASC

Little is known about the emotional pressures and practical management of daily challenges and, intra and interpersonal demands of raising a child as a parent with a diagnosis of Autistic Spectrum Conditions. The present study utilised a qualitative approach to understand perceptions of females diagnosed on the autistic spectrum of ‘being a parent’. Eight semi-structured interviews were analysed using Interpretative Phenomenological Analysis. Benefits and challenges of being a parent were highlighted alongside population-specific skill and characteristics associated with strength and resilience, love, nurture, routine and sensory considerations. Findings identify the need for population-specific specialist parenting support, provide direction for professionals in clinical settings and expand the paucity of research in this area

The effect of sauna bathing on lipid profile in young, physically active, male subjects

Objectives: The aim of the study was to evaluate effects of Finnish sauna bathing on lipid profile in healthy, young men. Material and Methods: Sixteen male subjects (20–23 years) were subjected to 10 sauna bathing sessions in a Finnish sauna every 1 or 2 days. The mean sauna temperature was 90±2°C, while humidity was 5–16%. Each session consisted of three 15-minute parts and a 2-minute cool-down between them. The following measurements were taken before and after the sauna sessions: body mass, heart rate, body skinfold thickness. The percentage fat content and then, the lean body mass were calculated. Total cholesterol, triacylglycerols, lipoprotein cholesterol LDL and HDL were measured in blood samples. Results: A statistically significant decrease of total cholesterol and LDL cholesterol was observed during 3 weeks of sauna treatment and in the week afterwards. A significant decline in triacylglycerols was found directly after the 1st and 24 h directly after the 10th sauna session. After the 10th sauna session the level of HDL cholesterol remained slightly increased, but this change was not statistically significant. A decrease in blood plasma volume was found directly after the 1st and the last sauna bathing session due to perspiration. An adaptive increase in blood plasma volume was also found after the series of 10 sauna sessions. Conclusions: Ten complete sauna bathing sessions in a Finnish sauna caused a reduction in total cholesterol and LDL cholesterol fraction levels during the sessions and a gradual return of these levels to the initial level during the 1st and the 2nd week after the experiment. A small, statistically insignificant increase in HDL-C level and a transient decline in triacylglycerols were observed after those sauna sessions. The positive effect of sauna on lipid profile is similar to the effect that can be obtained through a moderate-intensity physical exercise

Bioactive metabolites from macrofungi: ethnopharmacology, biological activities and chemistry

International audienceExploration of natural sources for novel bioactive compounds has been an emerging field of medicine over the past decades, providing drugs or lead compounds of considerable therapeutic potential. This research has provided exciting evidence on the isolation of microbe-derived metabolites having prospective biological activities. Mushrooms have been valued as traditional sources of natural bioactive compounds for many centuries and have been targeted as promising therapeutic agents. Many novel biologically active compounds have been reported as a result of research on medicinal mushrooms. In this review, we compile the information on bioactive structure-elucidated metabolites from macrofungi discovered over the last decade and highlight their unique chemical diversity and potential benefits to novel drug discovery. The main emphasis is on their anti-Alzheimer, antidiabetic, anti-malarial, anti-microbial, anti-oxidant, antitumor, anti-viral and hypocholesterolemic activities which are important medicinal targets in terms of drug discovery today. Moreover, the reader’s attention is brought to focus on mushroom products and food supplements available in the market with claimed biological activities and potential human health benefits