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961.
Marumoto Y Terai S Urata Y Matsumoto T Mizunaga Y Yamamoto N Jin H Fujisawa K Murata T Shinoda K Nishina H Sakaida I 《Biochemical and biophysical research communications》2008,367(3):546-552
We have previously shown that infusion of bone marrow cells (BMC) improves CCl4-induced cirrhosis. However, it is unclear why the injected BMC are resistant to CCl4 damage and subsequently improve the local microenvironment in damaged liver. To analyze the cellular phenomena involved in this process, we studied the damaged liver using electron microscopy. We found that CCl4 caused rough endoplasmic reticula to swell in hepatocytes. To analyze the gene expression patterns associated with this process, we conducted PCR-selected suppressive subtractive hybridization. We found that expression levels of HSP84, HSP40, and XBP1 differed markedly between control liver and liver infused with BMC. Immunohistochemical staining revealed that expression levels of HSP84 and HSP40 were markedly higher in the early phase of differentiation immediately after BMC infusion, but decreased over time. XBP1 expression remained high during the late phase, and GRP78 expression increased with XBP1 activation. We also found that GFP-positive BMC expressed XBP1 and GRP78. XBP1 and GRP78 are associated with ER stress. Thus, continuous high XBP1 and GRP78 expression might be essential for the survival and proliferation of BMC in a CCl4-induced persistent liver damage environment. 相似文献
962.
963.
Completely deacetylated chitosan was prepared by the treatment of commercial chitosan with 50% aqueous NaOH, and then derivatized into several new chitosan phenylcarbamate derivatives having a urea and an imide moiety at the 2-position of the glucosamine ring by the reaction with isocyanate and phthalic anhydride/isocyanate, respectively. The chitosan derivatives were coated on macroporous silica gel and evaluated as chiral stationary phases (CSPs) for high-performance liquid chromatography. The chiral recognition ability of the chitosan derivative was improved using the completely deacetylated chitosan. Among the novel chitosan derivatives, the 3,5-dimethyl-, 3,5-dichloro-, and 3,4-dichlorophenylcarbamate derivatives were found to possess relatively high chiral resolution abilities. The CSPs based on the chitosan phenylcarbamate-urea and -imide derivatives were stable in the presence of chloroform and ethyl acetate as a component of the eluents, and some racemates were better resolved by such eluents. The dichlorophenylcarbamate-imide derivatives showed a high chiral recognition for metal acetylacetonate complexes. The enantiomerization of Al(acac)3 was performed on the chitosan 3,5-dichlorophenylcarbamate-imide derivative CSP and the resulting chromatogram showed a 26% (+)-isomer enrichment. 相似文献
964.
David Luther Jodi Hilty Jack Weiss Caitlin Cornwall Missy Wipf Grant Ballard 《Biodiversity and Conservation》2008,17(8):1923-1935
Large tracts of natural habitat are being replaced by agriculture and urban sprawl in Mediterranean regions worldwide. We
have limited knowledge about the effects of human activities on native species in these landscapes and which, if any, management
practices might enhance the conservation of native biodiversity within them. Through a citizen volunteer bird-monitoring project,
we compared bird abundance and species richness in northern Californian riparian zones surrounded by vineyards, urban areas,
and natural areas. We assessed both local and landscape-level variables that may enhance native bird diversity in each land
use type. We also demonstrate a new statistical approach, generalized estimating equations, to analyze highly variable data,
such as that collected by volunteers. Avian abundance was highly correlated with both landscape context and local habitat
variables, while avian richness was correlated with local habitat variables, specifically shrub richness, and percent of tree
cover. In particular, shrub species richness has a strong positive correlation with riparian-preferring bird species. This
suggests that active local management of riparian zones in human-dominated landscapes can increase our ability to retain native
bird species in these areas. 相似文献
965.
Takahashi T Fujisawa T Umeno A Kozasa T Yamamoto K Sawada T 《Microbiology and immunology》2008,52(10):469-478
The purpose of this study was to clarify the taxonomic relationship between all the serovars and species of the genus Erysipelothrix by performing DNA-DNA hybridization experiments, the customary criterion for separation of bacterial genospecies. A total of 93 strains were isolated from a wide variety of sources, including pigs affected with acute or chronic erysipelas, other diseased animals, healthy animals, fish, retail meats, and environmental materials from throughout the world during the period 1958 to 1996. The present data on phenotypic characterization and DNA relatedness values demonstrate that 24 strains (96%) of E. tonsillarum are avirulent for swine, whereas 39 strains (66%) of genomic E. rhusiopathiae induced generalized or local urticarial lesion in swine after intradermal inoculation. This observation suggests that genomic E. tonsillarum has little etiological significance. Three minor groups contained several strains which exhibited minimal association with each type strain of E. rhusiopathiae and E. tonsillarum. In conclusion, it was confirmed that members of the E. rhusiopathiae and E. tonsillarum groups resemble each other in regard to many phenotypic characteristics, but differ in their ability to produce acid from saccharose and in their pathogenicity for swine. The genus Erysipelothrix certainly contains two main species: E. rhusiopathiae and E. tonsillarum. 相似文献
966.
Gehman JD O'Brien CC Shabanpoor F Wade JD Separovic F 《European biophysics journal : EBJ》2008,37(3):333-344
Aβ(1–42) peptide, found as aggregated species in Alzheimer’s disease brain, is linked to the onset of dementia. We detail
results of 31P and 2H solid-state NMR studies of model membranes with Aβ peptides and the effect of metal ions (Cu2+ and Zn2+), which are found concentrated in amyloid plaques. The effects on the lipid bilayer and the peptide structure are different
for membrane incorporated or associated peptides. Copper ions alone destabilise the lipid bilayer and induce formation of
smaller vesicles, but not when Aβ(1–42) is associated with the bilayer membrane. Aβ(25–35), a fragment from the C-terminal
end of Aβ(1–42), which lacks the metal coordinating sites found in the full length peptide, is neurotoxic to cortical cortex
cell cultures. Addition of metal ions has little effect on membrane bilayers with Aβ(25–35) peptides. 31P magic angle spinning NMR data show that Aβ(1–42) and Aβ(1–42)-Cu2+ complexes interact at the surface of anionic phospholipid membranes. Incorporated peptides, however, appear to disrupt the
membrane more severely than associated peptides. Solid-state 13C NMR was used to compare structural changes of Aβ(1–42) to those of Aβ(25–35) in model membrane systems of anionic phospholipids
and cholesterol. The Aβ peptides appeared to have an increase in β-strand structure at the C-terminus when added to phospholipid
liposomes. The inclusion of Cu2+ also influenced the observed chemical shift of residues from the C-terminal half, providing structural clues for the lipid-associated
Aβ/metal complex. The results point to the complex pathway(s) for toxicity of the full-length peptide.
Australian Society for Biophysics Special Issue: Metals and Membranes in Neuroscience. 相似文献
967.
968.
Oka H Tabara A Fujisawa K Jinnai M Nakajima R Arai S Ishihara C Tsuji M 《Experimental parasitology》2008,120(3):290-294
Despite the evidence suggesting that mouse pyruvate kinase (PK) deficiency provides protection against malaria in rodents, there has been no investigation of a parallel protective effect against babesiosis caused by Babesia rodhaini. Here, we examined whether a PK-deficient co-isogenic mouse strain (CBA-Pk-1slc) was protected against B. rodhaini infection. We demonstrated that deficiency in pyruvate kinase correlated with a significant protective effect, with survival rates of 50%, 58% and 56% in groups inoculated with 10, 103 and 105 parasitized erythrocytes, respectively. In contrast, control CBA (CBA-Pk-1+) mice exhibited 100% lethality, regardless of the infectious dose. In addition, CBA-Pk-1slc mice showed decreased levels of parasitemia when compared to CBA-Pk-1+ mice, in groups given 10, 103 or 105 parasitized erythrocytes. These results indicate that similar to PK deficiency in rodents, PK deficiency in mice affects the in vivo growth of B. rodhaini and protects the mice from lethal babesiosis. 相似文献
969.
Repulsive and attractive semaphorins cooperate to direct the navigation of cardiac neural crest cells 总被引:1,自引:0,他引:1
Toyofuku T Yoshida J Sugimoto T Yamamoto M Makino N Takamatsu H Takegahara N Suto F Hori M Fujisawa H Kumanogoh A Kikutani H 《Developmental biology》2008,321(1):251-262
The cardiac neural crest, a subpopulation of the neural crest, contributes to the cardiac outflow tract formation during development. However, how it follows the defined long-range migratory pathway remains unclear. We show here that the migrating cardiac neural crest cells (NCCs) express Plexin-A2, Plexin-D1 and Neuropilin. The membrane-bound ligands for Plexin-A2, Semaphorin (Sema)6A and Sema6B, are expressed in the dorsal neural tube and the lateral pharyngeal arch mesenchyme (the NCC “routes”). Sema3C, a ligand for Plexin-D1/neuropilin-1, is expressed in the cardiac outflow tract (the NCC “target”). Sema6A and Sema6B repel neural crest cells, while Sema3C attracts neural crest cells. Sema6A and Sema6B repulsion and Sema3C attraction are diminished either when Plexin-A2 and Neuropilin-1, or when Plexin-D1, respectively, are knocked down in NCCs. When RNAi knockdown diminishes each receptor in NCCs, the NCCs fail to migrate into the cardiac outflow tract in the developing chick embryo. Furthermore, Plexin-A2-deficient mice exhibit defects of cardiac outflow tract formation. We therefore conclude that the coordination of repulsive cues provided by Sema6A/Sema6B through Plexin-A2 paired with the attractive cue by Sema3C through Plexin-D1 is required for the precise navigation of migrating cardiac NCCs. 相似文献
970.
Takarada H Sekine M Kosugi H Matsuo Y Fujisawa T Omata S Kishi E Shimizu A Tsukatani N Tanikawa S Fujita N Harayama S 《Journal of bacteriology》2008,190(12):4139-4146