Biological and biochemical characterization of mice expressing prion protein devoid of the octapeptide repeat region after infection with prions

Accumulating lines of evidence indicate that the N-terminal domain of prion protein (PrP) is involved in prion susceptibility in mice. In this study, to investigate the role of the octapeptide repeat (OR) region alone in the N-terminal domain for the susceptibility and pathogenesis of prion disease, we intracerebrally inoculated RML scrapie prions into tg(PrPΔOR)/Prnp(0/0) mice, which express mouse PrP missing only the OR region on the PrP-null background. Incubation times of these mice were not extended. Protease-resistant PrPΔOR, or PrP(Sc)ΔOR, was easily detectable but lower in the brains of these mice, compared to that in control wild-type mice. Consistently, prion titers were slightly lower and astrogliosis was milder in their brains. However, in their spinal cords, PrP(Sc)ΔOR and prion titers were abundant and astrogliosis was as strong as in control wild-type mice. These results indicate that the role of the OR region in prion susceptibility and pathogenesis of the disease is limited. We also found that the PrP(Sc)ΔOR, including the pre-OR residues 23-50, was unusually protease-resistant, indicating that deletion of the OR region could cause structural changes to the pre-OR region upon prion infection, leading to formation of a protease-resistant structure for the pre-OR region.     

Soft Sedentarization: Bedouin Tourist Stations as a Response to Drought in Egypt’s Eastern Desert

Since the late 1990s, there has been a boom in tourism focused on the Khushmaan Ma’aza Bedouin of Egypt's northern Eastern Desert. While entrepreneurship on the part of a Bedouin, along with growing numbers of potential visitors, has fuelled this growth, a natural drought has pushed large numbers of Bedouin into the tourist trade. Almost no rain fell over the Khushmaan homeland between 1997 and 2005. Historically, such severe droughts compelled households to settle permanently along the Nile Valley, or men to take up temporary jobs in Red Sea coastal cities. The response to this drought is unique. Bedouin have clustered not in towns or villages but in a dozen tourist mahattas (stations) in the desert, where tourists visit for a few hours. The station structures are made of reeds, and two other factors make this sedentarization “soft”. Most Bedouin say they would disperse into the desert if rains return. The capricious trade itself could evaporate due to political events in the region. But is also possible that sustained drought combined with tourism impacts could take Khushmaan culture beyond a tipping point, depriving youth of traditional pastoral education and channeling them toward a permanent settled existence.

TAK1 Prevents Endothelial Apoptosis and Maintains Vascular Integrity

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An Aneuploidy-Free and Structurally Defined Balancer Chromosome Toolkit for Caenorhabditis elegans

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Somatostatin-like immunoreactivity in rat thyroid

Summary Somatostatin-like immunoreactive cells of the rat thyroid gland at various ages were investigated immunohistochemically. The number of cells per lobe in 5 m sections increased with age. Immunopositive cells were evident as small clusters in the older age group (8 to 24 months old) but not clustered in the younger age group (3 to 5 months old). This type of proliferation was termed S-cell hyperplasia in a manner similar to C-cell hyperplasia observed in the aged rat thyroid.     

Enzyme reactor with knitted fabric made of poly(vinyl alcohol) superfine filaments

Various supports and bio-reactors have been proposed. Packed bed reactors with polymer material in granular shape are most often employed in both laboratory and industry. But they have a disadvantage related to an increase in pressure drop. We already developed filter paper composed of short cut pieces of superfine filaments (SFF). It shows high performance, but its hydrodynamic resistance increases when substrate solution passes through it. A new type of enzyme reactor equipped with knitted SFF has been proposed. In this reactor, substrate does not pass through the support but flows along the thin channel and parallel to the support. Therefore, it is able to maintain flow rate constant during a considerable period. The productivity of the reactor fairly increases by reducing the thickness of the channel because linear velocity increases with the reduction of the thickness and that contributes to the decrease in mass transfer resistance.     

The crowding effect in an artificially mixed population of three species

Three species of root vegetables and leaf vegetables were grown in mixed stands at various densities and mixing ratios in tow experiments. The reciprocal equation of the crowding effect for two-species mixtures was utilized for the three-species mixtures. Interactions between species in two- and three-species mixtures were compared using a density conversion factor which converts the density of one species to the density of the other species on the basis of its effect on the growth of the species. The mean plant weights in a three-species mixture could be estimated by putting the density conversion factors obtained from two-species mixtures into the reciprocal equations for a three-species mixture.     

Impaired Motor Coordination in Mice Lacking Prion Protein

1. Prion protein (PrP^C) is a host-encoded glycoprotein constitutively expressed on the neuronal cell surface. Accumulation of its protease-resistant isoform is closely related to pathologic changes and prion propagation in the brain tissue of a series of prion diseases. However, the physiological role of PrP^C remains to be elucidated.2. After long-term observation, we noted impaired motor coordination and loss of cerebellar Purkinje cells in the aged mice homozygous for a disrupted PrP gene, a finding which strongly suggests that PrP^C plays a role in the long-term survival of Purkinje cells.3. We also describe the resistance of the PrP null mice to the prion, indicating the requirement of PrP^C for both the development of prion diseases and the prion propagation.     

S-allyl cysteine attenuated CCl4-induced oxidative stress and pulmonary fibrosis in rats

This study examined effects of S-allyl cysteine (SAC) on carbon tetrachloride (CCl4)-induced interstitial pulmonary fibrosis in Wistar rats. CCl4 (0.5 ml/kg) was intraperitoneally injected into rats twice a week for 8 weeks, and SAC (50, 100, or 200 mg/kg), N-acetyl cysteine (NAC, 200 or 600 mg/kg), or L-cysteine (CYS, 600 mg/kg) were orally administrated to rats everyday for 8 weeks. SAC significantly reduced the increases of transforming growth factor beta, lipid peroxides, AST, and ALT in plasma, induced by CCl4. Although CCl4 is mainly metabolized by hepatic cytochrome P450, CCl4 induced systemic inflammation and some organ fibrosis. SAC dose-dependently and significantly attenuated CCl4-induced systemic inflammation and fibrosis of lung. SAC also inhibited the decrease of thiol levels, the increase of inducible nitric oxide synthase expression, the infiltration of leukocytes, and the generation of reactive oxygen species in lungs. Although NAC and CYS attenuated CCl4-induced pulmonary inflammation and fibrosis, the order of preventive potency was SAC > NAC > CYS according to their applied doses. These results indicate that SAC is more effective than other cysteine compounds in reducing CCl4-induced lung injury, and might be useful in prevention of interstitial pulmonary fibrosis.