The effect of air temperature, velocity and humidity on respiration rate and rectal temperature as an expression of heat stress in gestating sows.

Global warming combined with increased production (i.e. more piglets, more milk and consequently more heat) means that sows are more often challenged by heat stress. The objective was to develop an effective temperature (ET) equation to predict how air temperature, velocity and humidity affect the respiration rate (RR), rectal temperature (RT) and skin temperature (ST) as an expression of heat stress in gestating sows in order to elucidate the relationship between the thermal parameters and the sows' perception of the environment. The experimental room was equipped with a negative pressure ventilation system with diffuse air inlet through the ceiling, electrical heaters, steam generators and dehumidifiers. An air distribution unit was constructed to generate vertical air velocity. A total of 16 gestating sows were exposed to three temperatures (25°C, 29°C and 33°C), two levels of relative humidity (30% and 70%) and three levels of air velocity (0.2 ms-1, 1 ms-1 and 2.5 ms-1). The RR, RT and ST were recorded every 30 min throughout the three 2-h test periods. The estimated effects of humidity and velocity in relation to effect of temperature was nearly independent of whether it was determined from RR or RT, whereas the effect of humidity was much smaller when determined from ST. High coefficients of determination (>0.97) were found for the second order relationship between the estimated ET and RR, RT and ST. An increase in relative humidity from 50 to 70% corresponded to an increase in ET of 0.9°C, while an increase in air velocity from 0.2 to 1.0 ms-1 corresponded to a decrease in ET of 1.2°C. The applied ET equation was useful for expressing the combined effect of temperature, humidity and velocity on animals exposed to heat stress. However, multiplying the effect of velocity by the temperature gradient between the animal and the surrounding air did not improve the estimation.

Mutations in the TLR3 signaling pathway and beyond in adult patients with herpes simplex encephalitis.

Herpes simplex encephalitis (HSE) in children has previously been linked to defects in type I interferon production downstream of Toll-like receptor (TLR)3. In the present study, we used whole-exome sequencing to investigate the genetic profile of 16 adult patients with a history of HSE. We identified novel mutations in IRF3, TYK2 and MAVS, molecules involved in generating innate antiviral immune responses, which have not previously been associated with HSE. Moreover, data revealed mutations in TLR3, TRIF, TBK1 and STAT1 known to be associated with HSE in children but not previously described in adults. All discovered mutations were heterozygous missense mutations, the majority of which were associated with significantly decreased antiviral responses to HSV-1 infection and/or the TLR3 agonist poly(I:C) in patient peripheral blood mononuclear cells compared with controls. Altogether, this study demonstrates novel mutations in the TLR3 signaling pathway in molecules previously identified in children, suggesting that impaired innate immunity to HSV-1 may also increase susceptibility to HSE in adults. Importantly, the identification of mutations in innate signaling molecules not directly involved in TLR3 signaling suggests the existence of innate immunodeficiencies predisposing to HSE beyond the TLR3 pathway.

Thermodynamic and Kinetic Requirements in Anaerobic Methane Oxidizing Consortia Exclude Hydrogen, Acetate, and Methanol as Possible Electron Shuttles.

Anaerobic methane oxidation (AMO) has long remained an enigma in microbial ecology. In the process the net reaction appears to be an oxidation of methane with sulfate as electron acceptor. In order to explain experimental data such as effects of inhibitors and isotopic signals in biomarkers it has been suggested that the process is carried out by a consortium of bacteria using an unknown compound to shuttle electrons between the participants. The overall change in free energy during AMO with sulfate is very small (?22 kJ mol-1) at in situ concentrations of methane and sulfate. In order to share the available free energy between the members of the consortium, the concentration of the intermediate electron shuttle compound becomes crucial. Diffusive flux of a substrate (i.e, the electron shuttle) between bacteria requires a stable concentration gradient where the concentration is higher in the producing organism than in the consuming organism. Since changes in concentrations cause changes in reaction free energies, the diffusive flux of a catabolic product/substrate between bacteria is associated with a net loss of available energy. This restricts maximal inter-bacterial distances in consortia composed of stationary bacteria. A simple theoretical model was used to describe the relationship between inter-bacterial distances and the energy lost due to concentration differences in consortia. Key parameters turned out to be the permissible concentration range of the electron shuttle in the consortium (i.e., the concentration range that allows both participants to gain sufficient energy) and the stoichiometry of the partial reactions. The model was applied to two known consortia degrading ethanol and butyrate and to four hypothetical methane-oxidizing consortia (MOC) based on interspecies transfer of hydrogen, methanol, acetate, or formate, respectively. In the first three MOCs the permissible distances between producers and consumers of the transferred compounds were less than two times prokaryotic cell wall diameters. Consequently, it is not possible that a MOC can be based on inter-species transfer of hydrogen, methanol, or acetate. Formate, on the other hand, is a possible shuttle candidate provided the bacteria are attached to one another. In general the model predicts that members of consortia thriving on low energy such as the MOC must adhere to each other and utilize a compound for the exchange of electrons that has a high permissible concentration range and a high diffusion coefficient and transfers as many electrons as possible per molecule.