Light modulation of postural flexor motoneurones in the tail-fan of the squat lobsterGalathea strigosa (Crustacea,Anomura)

Summary Photosensitivity in the terminal abdominal ganglion (G5) of an anomuran, the squat lobsterGalathea strigosa (Crustacea, Decapoda, Anomura), is described. In contrast to the caudal photoreceptors (CPRs) of long-tailed natantid and macruran decapod crustaceans, the caudal photosensitive elements in G5 inG. strigosa apparently lack the conventional spiking rostral conduction pathways to the thoracic ganglia, and instead make their output connections to a bilateral pair of tonic flexor motoneurones originating within the caudal ganglion itself. These flexor motoneurones modulate the activity of two bilaterally paired uropod coxopodite tonic flexor muscles. This photomodulated motoneurone (PMMN) activity is not abolished by sectioning the abdominal nerve cord anterior to G5. The pattern of photosensitivity, while differing from that shown by other CPRs, resembles instead the pattern attributed to photosensitive interneurones (PSIs) of rostral abdominal ganglia of crayfish and other long-tailed decapod crustaceans.The caudal PSIs inG. strigosa appear to be involved in the postural control of the tail-fan as it is held flexed against the cephalothorax.     

A rearing system for colostrum-deprived neonatal piglets

A system for the artificial rearing of colostrum-deprived neonatal piglets is described. A total of 443 piglets in 6 batches was reared. Each piglet, immediately after birth was placed in a separate incubator which was ventilated with heated filtered air. Piglets were fed hourly by an automatic system and were offered a liquid milk substitute. The mean survival rate up to the time piglets were transferred out of the rearing unit at 2 weeks of age was 78 +/- 7%. The mean daily live weight gain up to 2 weeks of age was 148 +/- 16 g/day and the dry matter intake over the same period was 154 +/- 10 g/day per piglet.     

Industrial road crossings drive changes in community structure and instream habitat for freshwater fishes in the boreal forest

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A computational thrombus formation model: application to an idealized two-dimensional aneurysm treated with bare metal coils

Cardiovascular implantable devices alter the biofluid dynamics and biochemistry of the blood in which they are placed. These perturbations can lead to thrombus formation which may or may not be desired, depending on the application. In this work, a computational model is developed that couples biofluid dynamics and biochemistry to predict the clotting response of blood to such devices. The model consists of 28 advection–diffusion–reaction partial differential equations to track proteins in the blood involved in clotting and utilizes boundary flux terms to model the initiation of the intrinsic clotting pathway at thrombogenic device surfaces. We use this model to simulate the transient clot growth within a 2D idealized bifurcation aneurysm filled with various distributions of bare metal coils with similar packing densities. The clot model predicts initial clot formation to occur in areas along coil surfaces where flow is minimal and where time-averaged shear rates are the smallest. Among the six coil-filled aneurysm cases simulated, maximum thrombus occlusion ranged between 80.8 and 92.2% of the post-treatment aneurysm volume and was achieved 325–450 s after treatment. With further refinement and validation, the computational clotting model will be a valuable engineering tool for evaluating and comparing the relative performance of cardiovascular implantable devices.     

Biochemical transformation of mouse cells by fragments of herpes simplex virus DNA.

Mouse L cells lacking the enzyme thymidine kinase (LMTK-) have been converted to a TK+ phenotype by infection with fragmented HSV2 strain 333 DNA. The DNA fragments used were either unique, produced by cleavage with the restriction endonucleases Eco RI and Hild III, or randomly produced by mechanical shearing. Survival in HAT medium was used initially to establish the TK+ phenotype; clones possessing the ability to grow in selective medium were picked on the basis of differing morphology and growth rates. Cytosol extracts of these clones possessed virus-specified TK activity identical to that present in cells lytically infected with HSV2, as indicated by thermolability and mobility on polyacrylamide gel electrophoresis. The transformed cells also exhibit HSV-specific immunofluorescence. Based on these transformation studies, it is possible to assign a map location to the TK gene on the HSV genome.     

Functional genomics of hsp-90 in parasitic and free-living nematodes

Heat shock protein 90 (Hsp-90) is a highly conserved essential protein in eukaryotes. Here we describe the molecular characterisation of hsp-90 from three nematodes, the free-living Caenorhabditis elegans (Ce) and the parasitic worms Brugia pahangi (Bp) and Haemonchus contortus (Hc). These molecules were functionally characterised by rescue of a Ce-daf-21 (hsp-90) null mutant. Our results show a gradient of rescue: the C. elegans endogenous gene provided full rescue of the daf-21 mutant, while Hc-hsp-90 provided partial rescue. In contrast, no rescue could be obtained using a variety of Bp-hsp-90 constructs, despite the fact that Bp-hsp-90 was transcribed and translated in the mutant worms. daf-21 RNA interference (RNAi) experiments were carried out to determine whether knock-down of the endogenous daf-21 mRNA in N2 worms could be complemented by expression of either parasite gene. However neither parasite gene could rescue the daf-21 (RNAi) phenotypes. These results indicate that factors other than the level of sequence identity are important for determining whether parasite genes can functionally complement in C. elegans.     

Hsp-90 and the biology of nematodes

Background  

Hsp-90 from the free-living nematode Caenorhabditis elegans is unique in that it fails to bind to the specific Hsp-90 inhibitor, geldanamycin (GA). Here we surveyed 24 different free-living or parasitic nematodes with the aim of determining whether C. elegans Hsp-90 was the exception or the norm amongst the nematodes. We combined these data with codon evolution models in an attempt to identify whether hsp-90 from GA-binding and non-binding species has evolved under different evolutionary constraints.     

Hepatoprotective activity of Schouwia thebica webb

Oral administration of alcoholic extracts of Schouwia thebica Webb showed that extracts are safe for human use. The studied extracts are considered safe, since they failed to induce death of mice in doses up to 4000 mg/kg body weight. Hepatoprotective activity was studied for the total alcoholic extracts. The total extract was fractionated in turn with diethyl ether, chloroform, ethyl acetate, and n-butanol, respectively. These extracts were tested for possible hepatoprotective activity. It was found that the ethyl acetate and n-butanol extracts of S. thebica Webb showed hepatoprotective activity. These extracts significantly reduced the increase in activities of ALT, AST, and GGT, and levels of glucose, triglycerides, and cholesterol in serum of CCl(4)-treated rats. The extracts showing activity were found to contain flavonoids; one new compound, chrysoeriol-7-O-xylosoide- (1,2)-arabinofuranoside (2), in addition to another known four compound chrysoeriol (1), quercetin (3), quercetin-7-O-rhamnoside (4), and kaempferol-3-O-beta-D-glucoside (5). The isolated new compound was mainly found to be responsible for this activity when tested on animals in the laboratory. The structures were established by melting point, UV spectroscopy, EI-Mass, Fab-Mass, and 1D and 2D NMR spectroscopic techniques on a 600MHz instrument.     

A Repurposing Strategy for Hsp90 Inhibitors Demonstrates Their Potency against Filarial Nematodes

Novel drugs are required for the elimination of infections caused by filarial worms, as most commonly used drugs largely target the microfilariae or first stage larvae of these infections. Previous studies, conducted in vitro, have shown that inhibition of Hsp90 kills adult Brugia pahangi. As numerous small molecule inhibitors of Hsp90 have been developed for use in cancer chemotherapy, we tested the activity of several novel Hsp90 inhibitors in a fluorescence polarization assay and against microfilariae and adult worms of Brugia in vitro. The results from all three assays correlated reasonably well and one particular compound, NVP-AUY922, was shown to be particularly active, inhibiting Mf output from female worms at concentrations as low as 5.0 nanomolar after 6 days exposure to drug. NVP-AUY922 was also active on adult worms after a short 24 h exposure to drug. Based on these in vitro data, NVP-AUY922 was tested in vivo in a mouse model and was shown to significantly reduce the recovery of both adult worms and microfilariae. These studies provide proof of principle that the repurposing of currently available Hsp90 inhibitors may have potential for the development of novel agents with macrofilaricidal properties.     

A computational model of the development of separate representations of facial identity and expression in the primate visual system

Experimental studies have provided evidence that the visual processing areas of the primate brain represent facial identity and facial expression within different subpopulations of neurons. For example, in non-human primates there is evidence that cells within the inferior temporal gyrus (TE) respond primarily to facial identity, while cells within the superior temporal sulcus (STS) respond to facial expression. More recently, it has been found that the orbitofrontal cortex (OFC) of non-human primates contains some cells that respond exclusively to changes in facial identity, while other cells respond exclusively to facial expression. How might the primate visual system develop physically separate representations of facial identity and expression given that the visual system is always exposed to simultaneous combinations of facial identity and expression during learning? In this paper, a biologically plausible neural network model, VisNet, of the ventral visual pathway is trained on a set of carefully-designed cartoon faces with different identities and expressions. The VisNet model architecture is composed of a hierarchical series of four Self-Organising Maps (SOMs), with associative learning in the feedforward synaptic connections between successive layers. During learning, the network develops separate clusters of cells that respond exclusively to either facial identity or facial expression. We interpret the performance of the network in terms of the learning properties of SOMs, which are able to exploit the statistical indendependence between facial identity and expression.