Molecular classification of scrapie strains in mice using gene expression profiling

Transmissible spongiform encephalopathy strains demonstrate specific prion characteristics, each with specific incubation times, and strain-specific patterns of deposition of the misfolded isoform of prion, PrPSc, in the brains of infected individuals. Different biochemical properties, including glycosylation profiles and the degree of proteinase resistance, have been shown to be strain-specific. However, no relationship between these properties and the phenotypic differences in the subsequent diseases has as yet been determined. Here we explore the utility of gene expression profiles to identify differences in the host response to different strains of prion agent. We identify 114 genes that exhibit significantly different levels of expression in mice infected with three strains of scrapie. These genes represent a pool of genes involved in a strain-specific response to prion disease. We have identified the most discriminatory genes from this list utilizing a wrapper-based feature selection algorithm with external cross-validation.     

Localisation and measurement of VIP in the genitourinary system of man and animals

VIP is present in the genitourinary system of man and animals. In man the highest concentrations are found in the penis, the uterus and vagina and in the urinary bladder. VIP nerves heavily innervate the erectile tissue of the male external genitalia, the uterine smooth muscle and blood vessels, the seromucous glands of the cervix, and the lamina propria and vaginal epithelium. In the urinary bladder, VIP nerves are located beneath the transitional epithelium, in the lamina propria and in the smooth muscle. Other areas well innervated by VIP nerves include the prostate, seminal vesicles and vasa deferentia. Chemical (phenol- and 6-OHDA) or surgical (hypogastric or pelvic nerve section) extrinsic denervation fail to deplete the genitourinary system of its VIP content, supporting the view that VIP-containing nerves originate from local ganglion cells. Indeed, neuronal cell bodies containing VIP are seen in the paracervical ganglia of the female genitalia, the para- or intramural bladder ganglia and scattered through the base of the cavernosum body, the neck of the bladder and the prostate. The finding of elevated levels of VIP in the local circulation after induced penile erection in man and mammals and the ability of VIP to relax the detrusor muscle of the bladder suggests that the peptide may be involved in penile erection and bladder relaxation, as does the marked VIP depletion in the penis or bladder in patients suffering from diabetic impotence or bladder instability.     

Xanthomonas campestris sensor kinase HpaS co-opts the orphan response regulator VemR to form a branched two-component system that regulates motility

Xanthomonas campestris pv. campestris (Xcc) controls virulence and plant infection mechanisms via the activity of the sensor kinase and response regulator pair HpaS/hypersensitive response and pathogenicity G (HrpG). Detailed analysis of the regulatory role of HpaS has suggested the occurrence of further regulators besides HrpG. Here we used in vitro and in vivo approaches to identify the orphan response regulator VemR as another partner of HpaS and to characterize relevant interactions between components of this signalling system. Bacterial two-hybrid and protein pull-down assays revealed that HpaS physically interacts with VemR. Phos-tag SDS-PAGE analysis showed that mutation in hpaS reduced markedly the phosphorylation of VemR in vivo. Mutation analysis reveals that HpaS and VemR contribute to the regulation of motility and this relationship appears to be epistatic. Additionally, we show that VemR control of Xcc motility is due in part to its ability to interact and bind to the flagellum rotor protein FliM. Taken together, the findings describe the unrecognized regulatory role of sensor kinase HpaS and orphan response regulator VemR in the control of motility in Xcc and contribute to the understanding of the complex regulatory mechanisms used by Xcc during plant infection.     

Isolation and partial characterization of human erythrocyte membrane NADH: (Acceptor) oxidoreductase

Gengliosides generally provide a small portion of the complex carbohydrate content of cell surfaces. An exception is the central nervous system where they comprise up to 5–10% of the total lipid of some membranes. This tissue is unique in that the quantity of lipid-bound sialic acid exceeds that of the protein-bound fraction. Over 30 different molecular species have been characterized to date. These range in complexity from sialosylgalactosyl ceramide with 2 sugars to the pentasialoganglioside of fish brain with 9 carbohydrate units. Virtually all cellular and subcellular fractions of brain that have been carefully examined contain gangliosides to one degree or another, but the majority of brain ganglioside is located in the neurons. Their mode of distribution within the neuron has not been entirely clarified by subcellular studies. Calculations based on reported values for axon terminal density and synaptosomal ganglioside concentration in the rat reveal that nerve endings contribute less than 12% of total cerebral cortical ganglioside. It is concluded that the plasma membranes of neuronal processes contain most of the neuronal ganglioside. These and other considerations suggest the possibility that gangliosides may be distributed over the entire neuronal surface.     

Role of Drosophila gene dunc-115 in nervous system

Axonal guidance signals are transduced through growth cone surface receptors to the interior leading to changes of actin dynamics and actin binding proteins, which are critical in determining the outcome of actin cytoskeleton reorganization. We report here the characterization of the Drosophila actin binding protein abLIM/Unc-115 homolog Dunc-115 and its role in the nervous system. Three Dunc-115 isoforms are identified as Dunc-115L, M and S, respectively. While Dunc-115L is a canonical homolog of Unc-115 with four LIM domains and one villin headpiece domain, Dunc-115M and S are novel isoforms without counterparts in other species. Our molecular modeling shows Dunc-115L is likely to bind to actin. Mutant analysis reveals that Dunc-115 is involved in axonal projection in both the visual and central nervous system.     

Nerve growth factor: Cellular localization and regulation of synthesis

1. The role of nerve growth factor (NGF) as a retrograde messenger between peripheral target tissues and innervating sympathetic and neural crest-derived sensory neurons is supported by the observations that (a) the interruption of retrograde axonal transport has the same effects as the neutralization of endogenous NGF by anti-NGF antibodies and (b) the close correlation between the density of innervation by fibers of NGF-responsive neurons and the levels of NGF and mRNANGF in their target organs. 2. In situ hybridization experiments have demonstrated that a great variety of cells in the projection field or NGF-responsive neurons is synthesizing NGF, among them epithelial cells, smooth muscle cells, fibroblasts, and Schwann cells. 3. The temporal correlation between the growth of trigeminal sensory fibers into the whisker pad of the mouse and the commencement of NGF synthesis initially suggested a causal relationship between these two events. However, in chick embryos rendered aneural by prior removal of the neural tube or the neural crest, it was shown that the onset of NGF synthesis in the periphery is independent of neurons, and is controlled by an endogenous "clock" whose regulatory mechanism remains to be established. 4. A comparison between NGF synthesis in the nonneuronal cells of the newborn rat sciatic nerve and that in the adult sciatic nerve after lesion provided evidence for the important regulatory role played by a secretory product of activated macrophages. The identity of this product is currently under investigation.     

The influence of spatial pulsed magnetic field application on neuropathic pain after tibial nerve transection in rat

The purpose of the study was to examine the influence of the spatial variable magnetic field (induction: 150–300?µT, 80–150?µT, 20–80?µT; frequency 40?Hz) on neuropathic pain after tibial nerve transection. The experiments were carried out on 64 male Wistar C rats. The exposure of animals to magnetic field was performed 1?d/20?min., 5?d/week, for 28?d. Behavioural tests assessing the intensity of allodynia and sensitivity to mechanical and thermal stimuli were conducted 1?d prior to surgery and 3, 7, 14, 21 and 28?d after the surgery. The extent of autotomy was examined. Histological and immunohistochemical analysis was performed. The use of extremely low-frequency magnetic fields of minimal induction values (20–80?µT/40?Hz) decreased pain in rats after nerve transection. The nociceptive sensitivity of healthy rats was not changed following the exposition to the spatial magnetic field of the low frequency. The results of histological and immunohistochemical investigations confirm those findings. Our results indicate that extremely low-frequency magnetic field may be useful in the neuropathic pain therapy.