Intrinsic brainstem circuits comprised of Chx10-expressing neurons contribute to reticulospinal output in mice

Glutamatergic reticulospinal neurons in the gigantocellular reticular nucleus (GRN) of the medullary reticular formation can function as command neurons, transmitting motor commands to spinal cord circuits to instruct movement. Recent advances in our understanding of this neuron-dense region have been facilitated by the discovery of expression of the transcriptional regulator, Chx10, in excitatory reticulospinal neurons. Here, we address the capacity of local circuitry in the GRN to contribute to reticulospinal output. We define two sub-populations of Chx10-expressing neurons in this region, based on distinct electrophysiological properties and somata size (small and large), and show that these populations correspond to local interneurons and reticulospinal neurons, respectively. Using focal release of caged glutamate combined with patch clamp recordings, we demonstrated that Chx10 neurons form microcircuits in which the Chx10 local interneurons project to and facilitate the firing of Chx10 reticulospinal neurons. We discuss the implications of these microcircuits in terms of movement selection

Modulation of the epithelial sodium channel (ENaC) by bacterial metalloproteases and protease inhibitors

The serralysin family of metalloproteases is associated with the virulence of multiple gram-negative human pathogens, including Pseudomonas aeruginosa and Serratia marcescens. The serralysin proteases share highly conserved catalytic domains and show evolutionary similarity to the mammalian matrix metalloproteases. Our previous studies demonstrated that alkaline protease (AP) from Pseudomonas aeruginosa is capable of activating the epithelial sodium channel (ENaC), leading to an increase in sodium absorption in airway epithelia. The serralysin proteases are often co-expressed with endogenous, intracellular or periplasmic inhibitors, which putatively protect the bacterium from unwanted or unregulated protease activities. To evaluate the potential use of these small protein inhibitors in regulating the serralysin induced activation of ENaC, proteases from Pseudomonas aeruginosa and Serratia marcescens were purified for characterization along with a high affinity inhibitor from Pseudomonas. Both proteases showed activity against in vitro substrates and could be blocked by near stoichiometric concentrations of the inhibitor. In addition, both proteases were capable of activating ENaC when added to the apical surfaces of multiple epithelial cells with similar slow activation kinetics. The high-affinity periplasmic inhibitor from Pseudomonas effectively blocked this activation. These data suggest that multiple metalloproteases are capable of activating ENaC. Further, the endogenous, periplasmic bacterial inhibitors may be useful for modulating the downstream effects of the serralysin virulence factors under physiological conditions. © 2014 Butterworth et al

Identification and characterization of the Bcl-2- associated athanogene (BAG) protein family in rice

The Bcl-2-associated athanogene (BAG) proteins are involved in the regulation of Hsp70/HSC70 in animals. There are six BAG genes in human that encode nine isoforms with different subcellular locations. Arabidopsis thaliana is reported to contain seven BAG proteins. We searched BAG proteins in Oryza sativa using profile-sequence (Pfam) and profile-profile (FFAS) algorithms and found six homologs. The BAG protein family in O. sativa can be grouped into two classes based on the presence of other conserved domains. Class I consists of four OsBAG genes (1 to 4) containing an additional ubiquitin-like domain, structurally similar to the human BAG1 proteins and might be BAG1 orthologs in plants. Class II consists of two OsBAG genes (5 and 6) containing calmodulin-binding domain. Multiple sequence alignment and structural models of O. sativa BAG proteins showed conservation of surface charge (except OsBAG5) and critical residues for the binding of BAG domain to Hsp70 nucleotide binding domain (NB). Meta analysis of microarray data showed that OsBAG genes are up or down regulated under different stresses (biotic and abiotic). Data obtained from real-time PCR of OsBAG genes under heat stress showed that maximum induction in the expression of all the genes occurred after one hour exposure to heat stress, while reduction in the expression was observed in the following time course and ultimately returned to the basal level at 24 h treatment. These results suggest that OsBAG genes might play important role at the onset of heat stress. A further detailed study may explore the exact function of the members of this gene family and help to make understanding of programmed cell death (PCD) mechanism in plants.Key words: Rice, ubiquitin-like domain, nucleotide-binding domain, real-time PCR

SL(2,R)SL(2,R) symmetry and quasi-normal modes in the BTZ black hole

With the help of two new intrinsic tensor fields associated with the $SL(2,R)$ quadratic Casimir of Killing fields, we uncover the $SL(2,R)$ symmetry satisfied by the solutions to the equations of motion for various fields in the BTZ black hole in a uniform way by performing tensor and spinor analysis without resorting to any specific coordinate system. Then with the standard algebraic method developed recently, we determine the quasi-normal modes for various fields in the BTZ black hole. As a result, the quasi-normal modes are given by the infinite tower of descendants of the chiral highest weight mode, which is in good agreement with the previous analytic result obtained by exactly solving equations of motion instead.Comment: JHEP style, 1+13 pages, version to appear in JHE

Focus estimation in academic environments using Computer Vision

In this paper we propose a system capable of monitoring students’ focus through cameras and using Computer Vision algorithms. Experimental results show that our system is capable of identifying students and tracking their focus during a class. At the end of the class, the system outputs graphical feedback to teachers regarding the average level of students’ focus. Moreover, it can identify lecture periods in which students were less watchful and the corresponding topics that potentially need extra focus. In this paper we start by presenting the architecture of the system, followed by results obtained both during a small-group workshop and a classroom with a large number of attending students. The main goal of this work is to contribute to the transformation of the classroom as a sensing environment, providing information to both teachers and students about their engagement during the class.publishe

Antagonistic bioactivity of an endophytic bacterium H-6

An endophytic bacterium, H-6, was isolated from leaves of Huperzia serrata grown in the Lushan Mountain, China. The strain was identified as Burkholderia sp. H-6 based on morphological, physiological and biochemical methods as well as on 16S rDNA analysis. This strain inhibited mycelium growth in vitro of 6 plant pathogenic fungi, especially of Phytophthora capsici, Fusarium graminearumt and Sclerotinia libertiana. In greenhouse pot experiments, soil drenches with cell densities of 106, 108 and 1010 CFU ml-1 H-6 reduced significantly P. capsici, in pepper seedling by 51.7, 58.7 and 60.2%, respectively, compared to the inoculated control, 3 weeks after sowing. Growth parameters such as lengths and fresh weights of roots and shoots of P. capsici-inoculated control plants were significantly lower compared to P. capsici-inoculated and H-6-treated plants, which is an added advantage of the strain used as potential biocontrol agent in future.Key words: Endophytic bacterium, 16S rDNA gene, antagonistic activity, Huperzia serrata

Sign-reversal of the in-plane resistivity anisotropy in hole-doped iron pnictides

The in-plane anisotropy of the electrical resistivity across the coupled orthorhombic and magnetic transitions of the iron pnictides has been extensively studied in the parent and electron-doped compounds. All these studies universally show that the resistivity $\rho_{a}$ across the long orthorhombic axis $a_{O}$ - along which the spins couple antiferromagnetically below the magnetic transition temperature - is smaller than the resistivity $\rho_{b}$ of the short orthorhombic axis $b_{O}$, i. e. $\rho_{a}<\rho_{b}$. Here we report that in the hole-doped compounds Ba$_{1-x}$K$_{x}$Fe$_{2}$As$_{2}$, as the doping level increases, the resistivity anisotropy initially becomes vanishingly small, and eventually changes sign for sufficiently large doping, i. e. $\rho_{b}<\rho_{a}$. This observation is in agreement with a recent theoretical prediction that considers the anisotropic scattering of electrons by spin-fluctuations in the orthorhombic/nematic state.Comment: This paper has been replaced by the new version offering new explanation of the experimental results first reported her

Residence time control in micromixers with vortex shedding

Residence time control is an important indicator of micromixer design. When using vortex shedding to enhance mixing efficiency in a micromixer, the relationship between residence time and vortex shedding becomes important; if residence time is shorter than shedding time, the fluid elements flow through the channel too quickly with no contribution of vortex shedding to mixing. Both residence time and vortex shedding depend on geometrical and flow parameters and hence in order to optimize micromixer design the effect of these parameters on mixing need to be well understood. Furthermore, the onset of vortex shedding in confined flows such as those encountered in micromixers need be elucidated. In this work, the flow field past a single cylindrical pin in a microchannel is studied experimentally using a high-speed PIV system. The effects of confinement on vortex formation are examined. Vortex shedding was observed for a channel height of two pin diameters and the shedding frequency increased with increasing lateral confinement (i.e. upon decrease in channel width at the same pin diameter). Therefore, controlling residence time via wake oscillations in pin microchannels is highly dependent on confinement

Purification, crystallization and X-ray crystallographic analysis of a putative exopolyphosphatase from Zymomonas mobilis

Exopolyphosphatase (PPX) enzymes degrade inorganic polyphosphate (poly-P), which is essential for the survival of microbial cells in response to external stresses. In this study, a putative exopolyphosphatase from Zymomonas mobilis (ZmPPX) was crystallized. Crystals of the wild-type enzyme diffracted to 3.3 Å resolution and could not be optimized further. The truncation of 29 amino acids from the N-terminus resulted in crystals that diffracted to 1.8 Å resolution. The crystals belonged to space group C2, with unit-cell parameters a = 122.0, b = 47.1, c = 89.5 Å, α = γ = 90, β = 124.5°. An active-site mutant that crystallized in the same space group and with similar unit-cell parameters diffracted to 1.56 Å resolution. One molecule was identified per asymmetric unit. Analytical ultracentrifugation confirmed that ZmPPX forms a dimer in solution. It was confirmed that ZmPPX possesses exopolyphosphatase activity against a synthetic poly-P substrate.published_or_final_versio

Dual-responsive supramolecular colloidal microcapsules from cucurbit[8]uril molecular recognition in microfluidic droplets

The macrocyclic host, cucurbit[8]uril, is used to facilitate cross-linking of colloidal particles and polymers in microdroplets resulting in thermo- and photo-responsive supramolecular colloidal microcapsules. Methyl viologen-bearing colloidal particles were prepared using template polymerisation and combined with cucurbit[8]uril and an azobenzene-functionalised polymer within microfluidic droplets. The colloidal particles self-assembled at the droplet interface, whereupon polymeric cross-links formed $\textit{via}$ ternary host-guest complexation with cucurbit[8]uril. The resultant supramolecular colloidal microcapsules were uniform in size and were able to retain a macromolecular cargo. It is shown that the capsule skin porosity, and consequently the rate of release of encapsulated cargo, can be remotely controlled $\textit{via}$ either temperature or light triggers. This simple and versatile method could be extended to other polymer or colloidal derivatives for the fabrication of nano- and microcapsules with dual stimuli response for controlled release.Engineering and Physical Sciences Research Council (Grant IDs: EP/K503496/1, EP/H046593/1), CSC Cambridge Scholarshi