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61.
Immunohistochemical characterization of cell types expressing the cellular prion protein in the small intestine of cattle and mice 总被引:3,自引:2,他引:1
Miyazawa K Kanaya T Tanaka S Takakura I Watanabe K Ohwada S Kitazawa H Rose MT Sakaguchi S Katamine S Yamaguchi T Aso H 《Histochemistry and cell biology》2007,127(3):291-301
The gastrointestinal tract is thought to be the main site of entry for the pathological isoform of the prion protein (PrPSc). Prion diseases are believed to result from a conformational change of the cellular prion protein (PrPc) to PrPSc. Therefore, PrPc expression is a prerequisite for the infection and spread of the disease to the central nervous system. However, the distribution
of PrPc in the gut is still a matter of controversy. We therefore investigated the localization of PrPc in the bovine and murine small intestine. In cattle, most PrPc positive epithelial cells were detected in the duodenum, while a few positive cells were found in the jejunum. PrPc was expressed in serotonin producing cells. In bovine Peyer’s patches, PrPc was distributed in extrafollicular areas, but not in the germinal centre of the jejunum and ileum. PrPc was expressed in myeloid lineage cells such as myeloid dendritic cells and macrophages. In mice, PrPc was expressed in some epithelial cells throughout the small intestine as well as in cells such as follicular dendritic cell
in the germinal centre of Peyer’s patches. In this study, we demonstrate that there are a number of differences in the localization
of PrPc between the murine and bovine small intestines. 相似文献
62.
The tobacco hornworm Manduca sexta, like many holometabolous insects, makes two versions of its thoracic legs. The simple legs of the larva are formed during embryogenesis, but then are transformed into the more complex adult legs at metamorphosis. To elucidate the molecular patterning mechanism underlying this biphasic development, we examined the expression patterns of five genes known to be involved in patterning the proximal-distal axis in insect legs. In the developing larval leg of Manduca, the early patterning genes Distal-less and Extradenticle are already expressed in patterns comparable to the adult legs of other insects. In contrast, Bric-a-brac and dachshund are expressed in patterns similar to transient patterns observed during early stages of leg development in Drosophila. During metamorphosis of the leg, the two genes finally develop mature expression patterns. Our results are consistent with the hypothesis that the larval leg morphology is produced by a transient arrest in the conserved adult leg patterning process in insects. In addition, we find that, during the adult leg development, some cells in the leg express the patterning genes de novo suggesting that the remodeling of the leg involves changes in the patterning gene regulation. 相似文献
63.
Although pancreatic exocrine acinar cells have the potential to transdifferentiate into pancreatic endocrine cells, the mechanisms are poorly understood. Here we report that intracellular signaling pathways, including those involving MAPK and phosphatidylinositol 3 (PI3)-kinase, are activated by enzymatic dissociation of pancreatic acinar cells and that spherical cell clusters are formed by cadherin-mediated cell-cell adhesion during transdifferentiation. Inhibition of PI3-kinase by LY294002 prevents spheroid formation by degrading E-cadherin and beta-catenin, blocking transdifferentiation into insulin-secreting cells. In addition, neutralizing antibody against E-cadherin suppresses the induction of genes characteristic of pancreatic beta-cells. We also show that loss of cadherin-mediated cell-cell adhesion induces and maintains a dedifferentiated state in isolated pancreatic acinar cells. Thus, disruption and remodeling of cadherin-mediated cell-cell adhesion is critical in pancreatic exocrine-to-endocrine transdifferentiation, in which the PI3-kinase pathway plays an essential role. 相似文献
64.
Kurusu S Matsui K Watanabe T Tsunou T Kawaminami M 《Cellular and molecular neurobiology》2008,28(8):1109-1118
This study characterized the phospholipase A2 (PLA2) activity in cerebral cortex of fetal rat brain and investigated effects of chemical inhibition of Ca2+-independent PLA2 (iPLA2) on neurite outgrowth and cell development of cortical neurons in vitro. The PLA2 activity in fetal brain was insensitive to a Ca2+-chelator EGTA and was significantly impaired by an iPLA2 inhibitor, bromoenol lactone (BEL). Following treatment with BEL, cortical neurons showed acute loss of neurites and impaired
cell body, which were clearly dose- and time-dependent. Nuclear staining revealed nuclear regression (shrinkage), but not
fragmentation, in BEL-treated cells. The cytotoxic effect of BEL was additive with arachidonic acid (AA) and AA alone also
induced neurite demise. BEL treatment resulted in increased production of prostaglandin E2. Overall data suggest that iPLA2, a primary PLA2 isoform in cerebral cortex, displays a housekeeping role in development and neurite outgrowth in cortical neurons in vitro
probably via maintaining phospholipid membrane remodeling rather than generating free fatty acids and lysophospholipids. 相似文献
65.
Kino K Satake R Morimatsu T Kuratsu S Shimizu Y Sato M Kirimura K 《Bioscience, biotechnology, and biochemistry》2008,72(9):2415-2417
Cellobiose phosphorylase from Clostridium thermocellum catalyzed the beta-anomer-selective synthesis of alkyl glucosides from cellobiose. Synthesis of alkyl beta-glucoside from inexpensive sucrose using cellobiose phosphorylase and sucrose phosphorylase from Pseudomonas saccharophilia was investigated. By combined use of these two phosphorylases, alkyl beta-glucoside was anomer-selectively synthesized from sucrose and alkyl alcohol. 相似文献
66.
Various heterocyclic sulfur compounds such as naphtho[2,1-b]thiophene (NTH) and benzo[b]thiophene (BTH) derivatives can be detected in diesel oil, in addition to dibenzothiophene (DBT) derivatives. Mycobacterium phlei WU-0103 was newly isolated as a bacterial strain capable of growing in a medium with NTH as the sulfur source at 50°C. M. phlei WU-0103 could degrade various heterocyclic sulfur compounds, not only NTH and its derivatives but also DBT, BTH, and their derivatives at 45°C. When M. phlei WU-0103 was cultivated with the heterocyclic sulfur compounds such as NTH, NTH 3,3-dioxide, DBT, BTH, and 4,6-dialkylDBTs as sulfur sources, monohydroxy compounds and sulfone compounds corresponding to starting heterocyclic sulfur compounds were detected by gas chromatography–mass spectrometry analysis, suggesting the sulfur-specific desulfurization pathways for heterocyclic sulfur compounds. Moreover, total sulfur content in 12-fold-diluted crude straight-run light gas oil fraction was reduced from 1000 to 475 ppm S, with 52% reduction, by the biodesulfurization treatment at 45°C with growing cells of M. phlei WU-0103. Gas chromatography analysis with a flame photometric detector revealed that most of the resolvable peaks, such as those corresponding to alkylated derivatives of NTH, DBT, and BTH, disappeared after the biodesulfurization treatment. These results indicated that M. phlei WU-0103 may have a good potential as a biocatalyst for practical biodesulfurization of diesel oil. 相似文献
67.
Low efficiencies of gene targeting hamper functional genomics in industrially important strains of Aspergillus niger. To generate strains showing high gene-targeting frequencies in A. niger WU-2223L producing citric acid, disruption of kueA encoding Ku80 homolog was performed. Disruption of kueA increased gene-targeting frequencies to 70%, and had no effect on citric acid production. 相似文献
68.
69.
70.
Jiacong Chen Susumu Shimura Kohtaro Kirimura Shoji Usami 《Applied microbiology and biotechnology》1993,38(6):714-718
Lipase high-producing mutants with petroleum products as carbon sources were successfully induced from Trichosporon fermentans WU-C12 by ultraviolet (UV) light irradiation. In the first mutation step, one mutant strain, PU-30, derived from strain WU-C12 was selected. The productivity of extracellular lipase of PU-30 reached 58 units (U)/ml in the medium containing kerosene, being approximately twice the productivity of the parental strain WU-C12. In the second mutation step, the mutant strain 2PU-18 was induced from strain PU-30. In medium containing kerosene, gas oil and liquid paraffin, the 2PU-18 produced 70 U/ml, 62 U/ml and 60 U/ml of extracellular lipase, respectively. When various n-alkanes (C8-C18) were used as carbon sources, the parental strain WU-C12 produced more than 20 U/ml of lipase only from C9-C12 alkanes, but 2PU-18 could produce more than 50 U/ml of lipase from C8-C18 alkanes. When cultivated for 3 days in medium containing liquid paraffin, the activity ratios of extracellular lipase to total lipase and the values of extracellular lipase activity per dry-cell weight were 0.44 and 0.65 U/mg for WU-C12, and 0.62 and 1.82 U/mg for 2PU-18, respectively. These results indicate that the mutant strain 2PU-18 is superior in both total lipase productivity and permeability of lipase to the parental strain WU-C12 when petroleum products are used as carbon sources.
Correspondence to: S. Usami 相似文献