Behavioural and electrophysiological responses of female Anopheles gambiae mosquitoes to volatiles from a mango bait

Attractive Toxic Sugar Baits (ATSB) are used in a “lure-and-kill” approach for management of the malaria vector Anopheles gambiae, but the active chemicals were previously unknown. Here we collected volatiles from a mango, Mangifera indica, juice bait which is used in ATSBs in Tanzania and tested mosquito responses. In a Y-tube olfactometer, female mosquitoes were attracted to the mango volatiles collected 24–48 h, 48–72 h and 72–96 h after preparing the bait but volatiles collected at 96–120 h were no longer attractive. Volatile analysis revealed emission of 23 compounds in different chemical classes including alcohols, aldehydes, alkanes, benzenoids, monoterpenes, sesquiterpenes and oxygenated terpenes. Coupled GC-electroantennogram (GCEAG) recordings from the antennae of An. gambiae showed robust responses to 4 compounds: humulene, (E)-caryophyllene, terpinolene and myrcene. In olfactometer bioassays, mosquitoes were attracted to humulene and terpinolene. (E)-caryophyllene was marginally attractive while myrcene elicited an avoidance response with female mosquitoes. A blend of humulene, (E)- caryophyllene and terpinolene was highly attractive to females (P < 0.001) when tested against a solvent blank. Furthermore, there was no preference when this synthetic blend was offered as a choice against the natural sample. Our study has identified the key compounds from mango juice baits that attract An. gambiae and this information may help to improve the ATSBs currently used against malaria vectors

Eavesdropping and crosstalk between secreted quorum sensing peptide signals that regulate bacteriocin production in Streptococcus pneumoniae.

Quorum sensing (QS), where bacteria secrete and respond to chemical signals to coordinate population-wide behaviors, has revealed that bacteria are highly social. Here, we investigate how diversity in QS signals and receptors can modify social interactions controlled by the QS system regulating bacteriocin secretion in Streptococcus pneumoniae, encoded by the blp operon (bacteriocin-like peptide). Analysis of 4096 pneumococcal genomes detected nine blp QS signals (BlpC) and five QS receptor groups (BlpH). Imperfect concordance between signals and receptors suggested widespread social interactions between cells, specifically eavesdropping (where cells respond to signals that they do not produce) and crosstalk (where cells produce signals that non-clones detect). This was confirmed in vitro by measuring the response of reporter strains containing six different blp QS receptors to cognate and non-cognate peptides. Assays between pneumococcal colonies grown adjacent to one another provided further evidence that crosstalk and eavesdropping occur at endogenous levels of signal secretion. Finally, simulations of QS strains producing bacteriocins revealed that eavesdropping can be evolutionarily beneficial even when the affinity for non-cognate signals is very weak. Our results highlight that social interactions can mediate intraspecific competition among bacteria and reveal that competitive interactions can be modified by polymorphic QS systems

No Dynamics in the Extremal Kerr Throat

Motivated by the Kerr/CFT conjecture, we explore solutions of vacuum general relativity whose asymptotic behavior agrees with that of the extremal Kerr throat, sometimes called the Near-Horizon Extreme Kerr (NHEK) geometry. We argue that all such solutions are diffeomorphic to the NHEK geometry itself. The logic proceeds in two steps. We first argue that certain charges must vanish at all times for any solution with NHEK asymptotics. We then analyze these charges in detail for linearized solutions. Though one can choose the relevant charges to vanish at any initial time, these charges are not conserved. As a result, requiring the charges to vanish at all times is a much stronger condition. We argue that all solutions satisfying this condition are diffeomorphic to the NHEK metric.Comment: 42 pages, 3 figures. v3: minor clarifications and correction

Visual Analysis of a Cold Rolling Process Using Data-Based Modeling

International Conference on Engineering Applications of Neural Networks (13th. 2012. Coventry Univ, Otaniemi, Finland

Biodistribution of 64 Cu in Inflamed Rats Following Administration of Two Anti-Inflammatory Copper Complexes

64Cu was administered in two anti-inflammatory formulations to normal rats and to rats with 2 forms of local inflammation, namely (a) an acute paw oedema (elicited with carrageenan) or (b) a chronic granulomatous response to an implanted irritant (Mycobacterium tuberculosis in a polyurethane sponge). The copper formulations used were (i) a slow release one consisting of Cu(II) salicylate applied dermally with ethanol/DMSO and (ii) short acting hydrophilic complex (Cu(I)Cu(II)-penicillamine)5- given subcutaneously. Three types of changes in copper biodistribution with these forms of inflammation were discerned based on determination of 64Cu and copper content in the following organs: inflammatory locus (foot or sponge implant), kidney, liver, spleen, adrenals, brain, blood, thymus, heart, and skin (site of application). The most evident changes were in the kidneys, liver, spleen, adrenals, thymus and serum from animals with chronic granulomatous inflammation. In contrast, a short term acute inflammatory stress (carrageenan paw oedema) had little effect. While copper D-penicillamine (applied subcutaneously) appeared to move as a bolus through the animals, the results with the percutaneous copper salicylate formulation are consistent with it providing a slow release source of copper(II). Exogenous 64Cu from both formulations was sequestered at inflammatory sites (relative to serum). This may partly explain how applied copper complexes can be anti-inflammatory

Brain injury induces specific changes in the caecal microbiota of mice via altered autonomic activity and mucoprotein production

Intestinal microbiota are critical for health with changes associated with diverse human diseases. Research suggests that altered intestinal microbiota can profoundly affect brain function. However, whether altering brain function directly affects the microbiota is unknown. Since it is currently unclear how brain injury induces clinical complications such as infections or paralytic ileus, key contributors to prolonged hospitalization and death post-stroke, we tested in mice the hypothesis that brain damage induced changes in the intestinal microbiota. Experimental stroke altered the composition of caecal microbiota, with specific changes in Peptococcaceae and Prevotellaceae correlating with the extent of injury. These effects are mediated by noradrenaline release from the autonomic nervous system with altered caecal mucoprotein production and goblet cell numbers. Traumatic brain injury also caused changes in the gut microbiota, confirming brain injury effects gut microbiota. Changes in intestinal microbiota after brain injury may affect recovery and treatment of patients should appreciate such changes